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1
Kash, Michael Mason. "Rydberg atom diamagnetism." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14367.
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Ribeiro, Sofia. "Atom-surface interactions with Rydberg atoms : an application to hybrid systems." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24166.
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This thesis focuses on theoretical quantum optics, with special emphasis on developing protocols in which engineered vacuum forces enable one to construct hybrid systems. In these systems, atoms are combined with solid-state devices in order to take advantage of their unique properties such as long coherence times of atoms and flexibility, tunability, scalability, and fast response offered by solid-state systems. Special attention is given to the study of atom-surface interactions with Rydberg atoms, where exact Fano-type diagonalization of the interaction Hamiltonian is obtained showing that, not only do Rydberg atoms suffer energy shifts, the presence of a surface leads to an alteration and admixture of the unperturbed eigenstates. Of particular interest are dispersion forces on graphene systems. We investigate whether and under which circumstances the Casimir-Polder potential between an atom and a graphene-substrate system is dominated by the interaction with graphene such that the effect of the substrate does not play an important role. We also explore the possibility to create a setup where dispersion forces could be use to bend a graphene sheet. Placing an atom close, at distances of a few hundred nanometers, to a free-standing graphene membrane we show that temporal changes in the atomic state change the Casimir-Polder interaction, thereby leading to the creation of a backaction force in the graphene sheet. Finally, we look at nonlinear atom--surface coupling processes with the aim of proposing a hybrid quantum circuit device in which individual field-excitations can be transferred between atoms and surface polaritons on demand. Deeper investigations of nonlinear processes reveal the existence of a sum rule for two-photon spontaneous decay rates that can be simply understood as a redistribution of photonic modes across the frequency spectrum where the total integrated number of modes is still conserved.
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Nguyen, Thanh Long. "Study of dipole-dipole interaction between Rydberg atoms : toward quantum simulation with Rydberg atoms." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066695/document.
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La simulation quantique offre un moyen très prometteur pour comprendre les systèmes quantiques corrélés macroscopiques. De nombreuses plateformes expérimentales sont en cours d'élaboration. Les atomes de Rydberg sont particulièrement intéressants grâce à leur forte interaction dipolaire de cours portée. Dans notre manip, nous préparons et manipulons des ensembles d'atomes de Rydberg excités à partir d'un nuage atomique ultra-froid piégé magnétiquement sur une puce à atome supraconductrice. La dynamique de l'excitation est contrôlée par le processus d'excitation du laser. Le spectre d'énergie d'interaction atomique des N corps est mesuré directment par spectroscopie micro-onde. Dans cette thèse, nous développons un modèle Monte Carlo rigoureux qui nous éclaire sur le processus d'excitation. En utilisant ce modèle, nous discutons de la possibilité de réaliser des simulations quantiques du transport d'énergie sur une chaîne 1D d'atomes de Rydberg de faible moment angulaire. De plus, nous proposons une plateforme innovante pour la réalisation de simulations quantiques. Elle repose sur une approche révolutionnaire basée sur un ensemble d'atomes de Rydberg dont le temps de vie est extrêmement long, qui interagissent fortement et qui sont piégés par laser. Nous présentons les résultats de simulations numériques et nous discutons du large éventail de problèmes qui peuvent être traités avec le modèle proposéQuantum simulation offers a highly promising way to understand large correlated quantum systems, and many experimental platforms are now being developed. Rydberg atoms are especially appealing thanks to their strong and short-range dipole-dipole interaction. In our setup, we prepare and manipulate ensembles of Rydberg atoms excited from an ultracold atomic cloud magnetically trapped above a superconducting chip. The dynamics of the Rydberg excitation can be controlled through the laser excitation process. The many-body atomic interaction energy spectrum is then directly measured through microwave spectroscopy. This thesis develops a rigorous Monte Carlo model that provides an insight into the excitation process. Using this model, we discuss a possibility to explore quantum simulations of energy transport in a 1D chain of low angular momentum Rydberg atoms. Furthermore, we propose an innovative platform for quantum simulations. It relies on a groundbreaking approach, based on laser-trapped ensemble of extremely long-lived, strongly interacting circular Rydberg atoms. We present intensive numerical results as well as discuss a wide range of problems that can be addressed with the proposed model
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Schmid, Thomas [Verfasser]. "Rydberg Molecules for Ultracold Ion-Atom Scattering / Thomas Schmid." München : Verlag Dr. Hut, 2019. http://d-nb.info/1196415536/34.
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Lu, Jun. "Classical trajectory Monte Carlo simulation of ion-Rydberg atom collisions." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968439713.
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Liu, Ivan Chen-Hsiu. "Ultracold Rydberg Atoms in Structured and Disordered Environments." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1231945394343-32656.
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The properties of a Rydberg atom immersed in an ultracold environment were investigated. Two scenarios were considered, one of which involves the neighbouring ground-state atoms arranged in a spatially structured configuration, while the other involves them distributed randomly in space. To calculate the influence of the multiple ground-state atoms on the Rydberg atom, Fermi-pseudopotential was used, which simplified greatly the numerical effort. In many cases, the few-body interaction can be written down analytically which reveals the symmetry properties of the system. In the structured case, we report the first prediction of the formation of ``Rydberg Borromean trimers''. The few-body interactions and the dynamics of the linear A-B-A trimer, where A is the ground-state atom and B is the Rydberg atom, were investigated in the framework of normal mode analysis. This exotic ultralong-range triatomic bound state exists despite that the Rydberg-ground-state interaction is repulsive. Their lifetimes were estimated using both quantum scattering calculations and semi-classical approximations which are found to be typically sub-microseconds. In the disordered case, the Rydberg-excitation spectra of a frozen-gas were simulated, where the nuclear degrees of freedom can be ignored. The systematic change of the spectral shape with respect to the density of the gas and the excitation of the Rydberg atom were found and studied. Some parts of the spectral shape can be described by simple scaling laws with exponents given by the basic properties of the atomic species such as the polarizability and the zero-energy electron-atom scattering length.
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Henkel, Nils. "Rydberg-dressed Bose-Einstein condensates." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-130499.
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My dissertation treats the physics of ultracold gases, in particular of Bose-Einstein condensates with long-ranged interactions induced by admixing a small fraction of a Rydberg state to the atomic ground state. The resulting interaction leads to the emergence of supersolid states and to the self-trapping of a Bose-Einstein condensate.
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Qadiri, Rafay Hasan. "H (Rydberg) atom photofragment translational spectroscopy of unsaturated hydride molecules." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411071.
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Abdussalam, Wildan. "Dynamics of Rydberg atom lattices in the presence of noise and dissipation." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227485.
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The work presented in this dissertation concerns dynamics of Rydberg atom lattices in the presence of noise and dissipation. Rydberg atoms possess a number of exaggerated properties, such as a strong van der Waals interaction. The interplay of that interaction, coherent driving and decoherence leads to intriguing non-equilibrium phenomena.
Here, we study the non-equilibrium physics of driven atom lattices in the presence of decoherence caused by either laser phase noise or strong decay. In the first case, we compare between global and local noise and explore their effect on the number of excitations and the full counting statistics. We find that both types of noise give rise to a characteristic distribution of the Rydberg excitation number. The main method employed is the Langevin equation but for the sake of efficiency in certain regimes, we use a Markovian master equation and Monte Carlo rate equations, respectively.
In the second case, we consider dissipative systems with more general power-law interactions. We determine the phase diagram in the steady state and analyse its generation dynamics using Monte Carlo rate equations. In contrast to nearest-neighbour models, there is no transition to long-range-ordered phases for realistic interactions and resonant driving. Yet, for finite laser detunings, we show that Rydberg atom lattices can undergo a dissipative phase transition to a long-range-ordered antiferromagnetic phase. We identify the advantages of Monte Carlo rate equations over mean field predictions.
Having studied the dynamics of Rydberg atom lattices, we study an application of the strong interactions in such systems for quantum information processing. We investigate the coherent exchange of a single photon between a superconducting microwave cavity and a lattice of strongly interacting Rydberg atoms in the presence of local electric field fluctuations plaguing the cavity surface. We show that despite the increased sensitivity of Rydberg states to electric fields, as compared to ground state atoms, the Rydberg dipole-dipole interaction can be used to protect the system against the dephasing induced by the local noise. Using $1/f$ and laser phase noise models, we show that compared to the case with non-interacting atoms, our system exhibits longer coherence lifetimes and larger retrieval efficiency of the photon after storing into the atoms.
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Liu, Ivan Chen-Hsiu. "Ultracold Rydberg Atoms in Structured and Disordered Environments." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23624.
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The properties of a Rydberg atom immersed in an ultracold environment were investigated. Two scenarios were considered, one of which involves the neighbouring ground-state atoms arranged in a spatially structured configuration, while the other involves them distributed randomly in space. To calculate the influence of the multiple ground-state atoms on the Rydberg atom, Fermi-pseudopotential was used, which simplified greatly the numerical effort. In many cases, the few-body interaction can be written down analytically which reveals the symmetry properties of the system. In the structured case, we report the first prediction of the formation of ``Rydberg Borromean trimers''. The few-body interactions and the dynamics of the linear A-B-A trimer, where A is the ground-state atom and B is the Rydberg atom, were investigated in the framework of normal mode analysis. This exotic ultralong-range triatomic bound state exists despite that the Rydberg-ground-state interaction is repulsive. Their lifetimes were estimated using both quantum scattering calculations and semi-classical approximations which are found to be typically sub-microseconds. In the disordered case, the Rydberg-excitation spectra of a frozen-gas were simulated, where the nuclear degrees of freedom can be ignored. The systematic change of the spectral shape with respect to the density of the gas and the excitation of the Rydberg atom were found and studied. Some parts of the spectral shape can be described by simple scaling laws with exponents given by the basic properties of the atomic species such as the polarizability and the zero-energy electron-atom scattering length.
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Jandura, Sven. "Optimized quantum gates for neutral atom quantum computers." Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAF027.
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Les atomes neutres sont récemment apparus comme une plate-forme compétitive pour l'informatique quantique. Le développement de portes quantiques intriquées de haute délité est la clé du succès de cette plateforme. Dans cette thèse, nous développons plusieurs protocoles nouveaux et optimisés pour l'implémentation de portes quantiques à deux et plusieurs qubits sur des atomes neutres. Nous introduisons la famille des protocoles temps-optimaux, qui implémentent une porte quantique donnée aussi rapidement que possible en appliquant une impulsion laser unique avec une phase dépendant du temps. Nous explorons également les protocoles de portes qui sont particulièrement robustes face à certaines sources d'erreurs expérimentales, et les portes qui sont optimisées pour leur utilisation dans un code de correction d'erreur quantique. En n, nous proposons deux nouveaux protocoles pour implémenter des portes multi-qubits non-locales sur des atomes neutres couplés à un mode de cavité commun qui peut être implémenté simplement par un pilotage classique de la cavité. Les résultats de cette thèse permettent d'obtenir des portes quantiques plus simples, de meilleure qualité et plus robustes sur des atomes neutres, et constituent une étape vers la réalisation de la vision d'un ordinateur quantiqueNeutral atoms have recently emerged as a competitive platform for quantum computing. The development of high delity entangling quantum gates is a key to success of this platform. In this thesis, we develop several new and optimized protocols for the implementation of two- and multi-qubit quantum gates on neutral atoms. We introduce the family of time-optimal protocols, which implement a given quantum gate as fast as possible by applying a single laser pulse with a time-dependent phase. We also explore gate protocols which are particularly robust against certain experimental error sources, and gates which are optimized for their use in a quantum error correction code. Finally, we propose two new protocols to implement non-local multi-qubit gates on neutral atoms coupled to a common cavity mode which can be implemented simply by a classical drive of the cavity. The results of this thesis allow for simpler, higher quality, and more robust quantum gates on neutral atoms, and constitute a step towards realizing the vision of a quantum computer
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Grabowski, Axel. "Aufbau einer Messapparatur zur Laserkühlung und hochauflösende Rydberg-Spektroskopie an 87 Rb-Atomen." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-25860.
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Schlagmüller, Michael [Verfasser]. "A single Rydberg Atom interacting with a Dense and Ultracold Gas / Michael Schlagmüller." München : Verlag Dr. Hut, 2016. http://d-nb.info/1115549685/34.
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Sibalic, Nikola. "Rydberg atom ensembles under dephasing and dissipation : from single- to many-body dynamics." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12224/.
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This thesis explores the effects of decoherence and dephasing on single- and many- body dynamics of spin-systems. A particular realisation of the spin systems that the work focuses on are highly excited, Rydberg states of atoms. A software library ARC (Alkali Rydberg Calculator) for calculating properties of Rydberg states in alkali metals is presented, with particular attention to the multi- atom and multi-level effects that influence many-body dynamics in realistic systems, and properties related to terahertz imaging with alkali atom Rydberg states. Dressed-state electromagnetically induced transparency (EIT) is proposed as a way of preparing uniform-phase spin-waves in ladder excitation schemes, making the collective excitation storage insensitive to motional dephasing. Proof of concept dressed state EIT experiments are presented. Strong resonant dressing is also theoretically analysed as a way of preparing velocity superposition of spin-waves. The developed theoretical model is in a good agreement with existing experimental data on single-photon many-atom quantum beats in diamond excitation schemes. By modelling the strongly driven Rydberg ensembles, many-body dynamics of driven-dissipative spin systems is analysed. Working in the limit of strong dephasing, the effects of fluctuations, the shape of interaction potential, spatial correlations and motion on non-equilibrium phase diagrams and the occurrence of bistability are examined. An ensemble averaged mean field model is introduced as an exact solution for completely uncorrelated ensembles. It is shown that the van der Waals interaction does not allow the occurrence of bistability, for which a finite dipolar core is required. The short-range interaction potential shape is found to have a profound influence on non-equilibrium phase diagrams, controlling the size of fluctuations in the dynamics. For a frozen system, several methods for identifying and quantifying bistable phases are introduced, and phase diagrams are reconstructed. It is shown that the temperature of external degrees of freedom, i.e. spin motion, can drive a non-equilibrium transition into the bistable phase.
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Sharkey, Keeper Layne. "Very Accurate Quantum Mechanical Non-Relativistic Spectra Calculations of Small Atoms & Molecules Employing All-Particle Explicitly Correlated Gaussian Basis Functions." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/560835.
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Due to the fast increasing capabilities of modern computers it is now feasible to calculate spectra of small atom and molecules with the greater level of accuracy than high-resolution measurements. The mathematical algorithms developed and implemented on high performance supercomputers for the quantum mechanical calculations are directly derived from the first principles of quantum mechanics. The codes developed are primarily used to verify, refine, and predict the energies associated within a given system and given angular momentum state of interest. The Hamiltonian operator used to determine the total energy in the approach presented is called the internal Hamiltonian and is obtained by rigorously separating out the center-of-mass motion (or the elimination of translational motion) from the laboratory-frame Hamiltonian. The methods utilized in the articles presented in this dissertation do not include relativistic corrections and quantum electrodynamic effects, nor do these articles assume the Born-Oppenheimer (BO) approximation with the exception of one publication. There is one major review article included herein which describes the major differences between the non-BO method and the BO approximation using explicitly correlated Gaussian (ECG) basis functions. The physical systems studied in this dissertation are the atomic elements with Z < 7 (although the discussion is not limited to these) and diatomic molecules such as H₂⁺ and H₂ including nuclear isotopic substitution studies with deuterium and tritium, as well as electronic substitutions with the muon particle. Preliminary testing for triatomic molecular functionals using a model potential is also included in this dissertation. It has been concluded that using all-particle ECGs with including the addition of nonzero angular momentum functions to describe nonzero angular momentum states is sufficient in determining the energies of these states for both the atomic and molecular case.
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Dietsche, Eva-Katharina. "Quantum sensing with Rydberg Schrödinger cat states." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066211/document.
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Les atomes de Rydberg sont des états très excités, dans lesquels un électron est placé sur une orbite éloignée du noyau. Leur grand dipôle électrique les rend très sensibles à leur environnement électromagnétique. En utilisant des champs microondes et radiofréquences, nous préparons des états quantiques non-classiques spécialement conçus pour exploiter au mieux cette sensibilité et mesurer des champs électriques et magnétiques avec une grande précision. Dans la première partie, nous préparons des états chats de Schrödinger, superpositions d'orbitales de polarisabilités très différentes, qui nous permettent de mesurer de petites variations du champ électrique statique avec une sensibilité bien supérieure à la limite quantique standard et proche de la limite Heisenberg fondamentale. Nous atteignons une sensibilité par atome de 30mV/m pour un temps d'interrogation de 200ns, faisant de notre système l'un des électromètres les plus sensibles à ce jour. Nous implémentons ensuite des manipulations plus complexes de l'atome. Grâce à une technique d'écho de spin qui exploite la richesse de la multiplicité Rydberg, nous mesurons les corrélations temporelles du champ électrique avec une bande passante de l'ordre du MHz. Dans la partie finale, nous préparons une superposition quantique de deux états circulaires de nombres quantiques magnétiques opposés. Cet état très non-classique correspond à un électron tournant à la fois dans des directions opposées sur la même orbite. La grande différence de moment magnétique entre les deux composantes de la superposition, de l'ordre de 100muB, ouvre la voie à la mesure de petites variations du champ magnétique avec une grande bande passanteRydberg atoms are highly excited states, in which the electron is orbiting far from the nucleus. Their large electric dipole makes them very sensitive to their electromagnetic environment. Using a combination of microwave and radio-frequency fields, we engineer non-classical quantum states specifically designed to exploit at best this sensitivity for electric and magnetic field metrology. In the first part, we prepare non-classical states, similar to Schrödinger cat states, superpositions of two orbitals with very different polarizabilities, that allow us to measure small variations of the static electric field with a sensitivity well beyond the standard quantum limit and close to the fundamental Heisenberg limit. We reach a single atom sensitivity of 30mV/m for a 200ns interrogation time. It makes our system one of the most sensitive electrometers to date. We then implement more complex manipulations of the atom. Using a spin-echo technique taking advantage of the full extent of the Rydberg manifold, we perform a correlation function measurement of the electric field with a MHz bandwidth.In the final part, we prepare a quantum superposition of two circular states with opposite magnetic quantum numbers. It corresponds to an electron rotating at the same time in opposite directions on the same orbit, a rather non-classical situation. The huge difference of magnetic moment between the two components of the superposition, in the order of 100muB, opens the way to the measurement of small variations of the magnetic field with a high bandwidth
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Hermann, Avigliano Carla. "Towards deterministic preparation of single Rydberg atoms and applications to quantum information processing." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066351/document.
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Les atomes de Rydberg couplés à des cavités supraconductrices sont des outils remarquables pour l’exploration des phénomènes quantiques élémentaires et des protocoles d’information quantique. Ces atomes «géants» ont des propriétés uniques. Ils sont soumis à une forte interaction dipôle-Dipôle, fonction de la distance interatomique, qui est responsable du mécanisme de blocage dipolaire : dans le régime de Van der Waals, l’énergie d’interaction croît comme n11, où n est le nombre quantique principal. Si on illumine un nuage atomique avec un laser d’excitation à la fréquence de la transition de Rydberg pour un atome isolé, on s’attend à exciter au plus un atome dans un volume de blocage de ⇠ 8(μm)3. Nous avons mis en place une expérience pour préparer un atome de Rydberg de façon déterministe. Elle utilise un petit nuage d’atomes de rubidium 87 dans l’état fondamental, piégés magnétiquement sur un puce à atomes supraconductrice à 4 K, et excités à l’aide de lasers vers les états de Rydberg. L’effet de blocage dipôlaire est sensible à l’élargissement spectral de la transition par des champs électriques parasites. Une fois unatome excité dans l’état cible 60S1/2↵, nous explorons les transitions atomiques étroites, de longueur d’onde millimétrique, entre états de Rydberg pour étudier ces champs parasites. La surface de notre puce étant couverte d’une pellicule d’or, nous observons comme d’autres groupes de recherche de forts gradients de champs électriques, dus au dépôt progressif d’atomes de rubidium à la surface de la puce. Nous contournons le problème, en déposant une couche de rubidium métallique sur la puce. Les gradients sont alors réduits d’un ordre de grandeur. Cette amélioration nous permet d’observer des temps de cohérence très élevés, de l’ordre de la milliseconde, pour des atomes de Rydberg au voisinage d’une puce supraconductrice.Sur le plan théorique, nous présentons un protocole simple pour la création rapide et efficace de superpositions quantiques de deux champs cohérents d’amplitudes classiques différentes dans une cavité. Il repose sur l’interaction de deux atomes à deux niveaux avec le champ dans la cavité. Leur détection avec une grande probabilité dans un état bien défini projette le champ dans une superposition mésoscopique d’états du champ. Nous montrons que ce protocole est nettement plus efficace que ceux utilisant un seul atome. Nous réalisons cette étude dans le contexte de l’électrodynamique en cavité (CQED), où les atomes à deux niveaux sont des atomes de Rydberg de grand temps de vie interagissant avec le champ d’une cavité micro-Ondes supraconductrice. Mais ce travail peut également s’appliquer au domaine en plein essor de l’électrodynamique quantique des circuits. Dans ces deux contextes, il peut conduire à d’intéressantes études expérimentales de la décohérence à la frontière quantique-ClassiqueRydberg atoms and superconducting cavities are remarkable tools for the exploration of basic quantum phenomena and quantum information processing. These giant atoms are blessed with unique properties. They undergo a strong distance-Dependent dipole-Dipole interaction that gives rise to the dipole blockade mechanism: in the Van der Waals regime, this energy shift scales as n11, where n is the principal quantum number. If we shine an excitation laser tuned at the frequency of the isolated atomic transition on an atomic cloud, we expect to excite at most one atom within a blockade volume of ⇠ 8(μm)3. We have set up an experiment to prepare deterministically one Rydberg atom. It uses a small cloud of ground-State Rubidium 87 atoms, magnetically trapped on a superconducting atom chip at 4 K, and laser-Excited to the Rydberg states. The dipole blockade effect is sensitive to the line broadening due to the stray electric fields. Once an atom has been excited to our target state HH 60S1/2↵, we explore the narrow millimeter-Wave transitions between Rydberg states in order to assess these stray fields . With a gold-Coated front surface for the chip, we observe as other groups large field gradients due to slowly deposited Rubidium atoms. We circumvent this problem by coating the chip with a metallic Rubidium layer. This way the gradients are reduced by an order of magnitude. This improvement allows us to observe extremely high coherence times, in the millisecond range, for Rydberg atoms near a superconducting atom-Chip. Theoretically, we present a simple scheme for the fast and efficient generation of quantum superpositions of two coherent fields with different classical amplitudes in a cavity. It relies on the simultaneous interaction of two two-Level atoms with the field. Their final detection with a high probability in the proper state projects the field onto the desired mesoscopic field state superposition (MFSS). We show that the scheme is notably more efficient than those using a single atom. This work is done in the context of cavity QED, where the two-Level systems are circular Rydberg atoms whose lifetime may reach milliseconds, interacting with the field of a superconducting microwave cavity. But this scheme is also highly relevant for the thriving field of circuit-QED. In both contexts, it may lead to interesting experimental studies of decoherence at the quantum-Classical boundary
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Leonhardt, Karsten. "Interplay of excitation transport and atomic motion in flexible Rydberg aggregates." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-213759.
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Strong resonant dipole-dipole interactions in flexible Rydberg aggregates enable the formation of excitons, many-body states which collectively share excitation between atoms. Exciting the most energetic exciton of a linear Rydberg chain whose outer two atoms on one end are closely spaced causes the initiation of an exciton pulse for which electronic excitation and diatomic proximity propagate directed through the chain. The emerging transport of excitation is largely adiabatic and is enabled by the interplay between atomic motion and dynamical variation of the exciton.
Here, we demonstrate the coherent splitting of such pulses into two modes, which induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. The mechanism exploits local nonadiabatic effects at a conical intersection, turning them from a decoherence source into an asset. The conical intersection is a consequence of the exciton pulses moving along a linear Rydberg chain and approaching an additional linear, perpendicularly aligned Rydberg chain. The intersection provides a sensitive knob controlling the propagation direction and coherence properties of exciton pulses.
We demonstrate that this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains.
Initially, we demonstrate the pulse splitting on planar aggregates with atomic motion one-dimensionally constrained and employing isotropic interactions. Subsequently, we confirm the splitting mechanism for a fully realistic scenario in which all spatial restrictions are removed and the full anisotropy of the dipole-dipole interactions is taken into account. Our results enable the experimental observation of non-adiabatic electronic dynamics and entanglement transport with Rydberg atoms. The conical intersection crossings are clearly evident, both in atomic mean position information and excited state spectra of the Rydberg system. This suggests flexible Rydberg aggregates as a test-bench for quantum chemical effects in experiments on much inflated length scales. The fundamental ideas discussed here have general implications for excitons on a dynamic network.
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Labuhn, Henning. "Rydberg excitation dynamics and correlations in arbitrary 2D arrays of single atoms." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLO002/document.
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Dans cette thèse, nous mesurons la dynamique cohérente et les corrélations spatiales des excitations Rydberg dans des matrices 2D d’atomes uniques.Nous utilisons un modulateur spatial de lumière pour façonner la phase spatiale d'un faisceau laser de piégeage optique avant de le focaliser avec une lentille asphérique de grande ouverture numérique. En imprimant une phase appropriée sur le faisceau laser, nous pouvons créer des matrices 2D de pièges optiques, de forme arbitraire et facilement reconfigurables, avec jusqu'à 100 pièges séparées de quelques micromètres. Les pièges sont chargés à partir d'un nuage d'atomes froids de 87Rb, et due aux collisions assistées par la lumière, au plus un seul atome peut être présent dans chaque piège en même temps. Une caméra CCD sensible permet en temps réel l'imagerie de la fluorescence atomique émanant des pièges, ce qui nous permet de détecter individuellement la présence d'un atome dans chaque piège avec une précision presque parfaite.Pour créer des interactions importantes entre les atomes uniques, nous les excitons vers des états de Rydberg, qui sont des états électroniques avec un nombre quantique principal élevé.Un faisceau supplémentaire d'adressage permet la manipulation individuelle d'un atome sélectionné dans la matrice.La connaissance précise, de la fois de la matrice des atomes préparé et des positions des excitations Rydberg, nous a permis de mesurer l’augmentation collective de la couplage optique dans le régime de blocage Rydberg, où une seule excitation est partagée de façon symétrique entre tous les atomes de la matrice.Dans le régime où l'interaction ne s’étend que sur quelques sites, nous avons mesuré la dynamique et les corrélations spatiales des excitations Rydberg, dans des matrices d’atomes à une et deux dimensions. La comparaison à une simulation numérique d'un modèle d'Ising quantique d'un système de spin-1/2 montre un accord exceptionnel pour les matrices où l'effet de l'anisotropie de l’interaction Rydberg-Rydberg est faible. Les résultats obtenus démontrent que les atomes Rydberg uniques sont une plate-forme bien adaptée pour la simulation quantique des systèmes de spinIn this thesis, we measure the coherent dynamics and the pair correlations of Rydberg excitations in two-dimensional arrays of single atoms.We use a spatial light modulator to shape the spatial phase of a single optical dipole trap beam before focusing it with a high numerical-aperture aspheric lens. By imprinting an appropriate phase pattern on the trap beam, we can create arbitrarily shaped and easily reconfigurable 2D arrays of high-quality single-atom traps, with trap-spacings of a few micrometers for up to 100 traps. The traps are loaded from a cloud of cold 87Rb atoms, and due to fast light-assisted collisions of atoms inside the traps, at most one atom can be present in each trap at the same time. A sensitive CCD camera allows the real-time, site-resolved imaging of the atomic fluorescence from the traps, enabling us to detect the presence of an atom in each individual trap with almost perfect accuracy.In order to induce strong, tunable interactions between the atoms in the array, we coherently laser-excite them to Rydberg states, which are electronic states with a high principal quantum number.An additional addressing beam allows the individual manipulation of an atom at a selected site in the array.The precise knowledge of both the prepared atom array and the positions of the Rydberg excitations allowed us to measure the collective enhancement of the optical coupling strength in the regime of full Rydberg blockade, where one single excitation is shared symmetrically among all atoms in the array.In the regime where the strong interaction only extends over a few sites, we measured the dynamics and the spatial pair-correlations of Rydberg excitations, in one- and two-dimensional atom arrays. The comparison to a numerical simulation of a quantum Ising model of a spin-1/2 system shows an exceptional agreement for trap geometries where the effect of the anisotropy of the Rydberg-Rydberg interaction is small. The obtained results demonstrate that single Rydberg atoms are a suitable platform for the quantum simulation of spin systems
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Bornet, Guillaume. "Quantum simulation of the dipolar XY model using arrays of Rydberg atoms." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP065.
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Les matrices d'atomes de Rydberg sont des plateformes prometteuses pour la simulation quantique de modèles de spin. Cette thèse résume le travail accompli au cours de mes quatre années de doctorat, en se concentrant sur l'étude du modèle XY dipolaire. La thèse est divisée en trois parties. Dans la première partie, je décris les principes de fonctionnement de la plateforme et détaille les diverses améliorations que nous avons apportées. La deuxième partie se concentre sur l'étude de l'état fondamental du modèle XY en utilisant diverses géométries 2D. La troisième partie présente nos études sur la dynamique hors-équilibre du modèle XY.Notre simulateur quantique est basé sur le piégeage et le refroidissement d'atomes individuels de Rubidium dans un réseau de pinces optiques. Une fois piégés, ces atomes sont excités dans des états de Rydberg, permettant de fortes interactions dipôle-dipôle entre eux, ce qui permet ainsi l'implémentation de modèles de spin tels que le modèle XY. Récemment, nous avons développé une méthode combinant des impulsions micro-ondes et des faisceaux d'adressage optique pour manipuler l'état de chaque spin. Cette méthode nous permet d'effectuer des rotations locales des spins qui a pour but : soit de préparer le système dans un état spécifique, soit de mesurer les corrélations entre les spins dans des bases différentes.En combinant notre récente capacité à effectuer des rotations locales avec une procédure adiabatique, nous avons préparé les états d'énergie les plus bas et les plus élevés du modèle XY dipolaire dans des réseaux carrés bidimensionnels. Nous avons caractérisé ces états et démontré qu'ils possèdent un ordre ferromagnétique et antiferromagnétique complexe. En particulier, nous avons évalué le rôle joué par la relative longue portée des interactions dipolaires, qui décroissent en fonction du cube de la distance. Nous avons montré que ces interactions modifient les propriétés des états ferromagnétiques et antiferromagnétiques, conduisant à un ordre à longue portée dans le premier cas et introduisant de la frustration dans le second. Nous avons également poursuivi notre exploration du modèle XY dans son état fondamental en utilisant des géométries fortement frustrées telles que les réseaux de Kagome. Les travaux théoriques ont prédit que l'état fondamental de ces systèmes pourrait être une phase exotique de la matière appelée liquides de spin. Je présente nos premiers résultats vers la réalisation et la caractérisation de ces phases exotiques.Enfin, nous avons étudié la dynamique XY d'états hors-équilibre. Nous avons d'abord démontré que, comme prévu par des travaux théoriques récents, le modèle XY dipolaire peut produire des états dits de « spin squeezing ». Ces états sont particulièrement intéressants dans le contexte de la métrologie quantique, car ils peuvent améliorer la sensibilité des mesures. Nous avons caractérisé ce « squeezing », montrant que son gain métrologique augmente avec la taille du système. Nous avons également proposé différents protocoles pouvant être utilisés pour des applications métrologiques. En utilisant une méthode de spectroscopie hors équilibre appelée « quench spectroscopy experiment », nous avons mesuré la relation de dispersion du modèle XY dipolaire, révélant un comportement caractéristique prédit par les travaux théoriques. Cette méthode est relativement générale et peut donc être appliquée à d'autres plateformes de simulateurs quantiques présentant différents modèles de spinArrays of Rydberg atoms have proven to be a promising platform for the quantum simulation of spin models. This thesis summarizes the work accomplished during my four years of PhD, focusing on the study of the dipolar XY model. The thesis is divided into three parts. In the first part, I describe the working principles of the platform and detail the various upgrades we performed. The second part focuses on the study of the ground state of the XY model using various 2D geometries. The third part presents our studies of the XY quench dynamics.Our quantum simulator is based on trapping and cooling individual Rubidium atoms in an array of optical tweezers. Once trapped, these atoms are excited to the Rydberg state, allowing for strong dipole-dipole interactions between them, thus enabling the implementation of spin models such as the XY model. Recently, we developed a method combining microwave pulses and optical addressing beams to manipulate the state of each spin. This method allows us to perform local rotations of the spins, either to prepare the system in a specific state or to measure cross-basis correlations between the spins.Combining our recent ability to perform local rotations with an adiabatic procedure, we prepared the lowest and highest energy states of the dipolar XY model in 2D square arrays. We characterized these states and demonstrated that they exhibit complex ferromagnetic and antiferromagnetic order. In particular, we assessed the role played by the relatively long-range tail of the dipolar interactions, which decay as the cube of the distance. We showed that these interactions modify the properties of the ferromagnetic and antiferromagnetic states, leading to long-range order in the former and introducing frustration in the latter. We also continued our exploration of the ground state XY model using highly frustrated geometries such as Kagome arrays. Theoretical works have predicted that the ground state of these systems could be an exotic phase of matter called spin liquids. I present our initial results toward the realization and characterization of these exotic phases.Finally, we investigated quench experiments. We first demonstrated that, as predicted by recent theoretical works, the dipolar XY model can produce spin-squeezed states. These squeezed states are particularly interesting in the context of quantum metrology, as they can improve the sensitivity of measurements. We characterized this squeezing, showing that it is scalable, meaning that its metrological gain (squeezing parameter) increases with the system size. We also proposed different protocols that can be used for metrological applications. By using a quench spectroscopy method, we measured the dispersion relation of the dipolar XY model, revealing a characteristic behaviour predicted by theoretical works. This method is relatively general and can thus be applied to other quantum simulator platforms exhibiting different spin models
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Dorenkamp, Yvonne Jeannette. "Inelastic H-Atom scattering from ultra-thin films." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E49B-7.
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Kime, Leila. "Production d'une source d'ions césium monocinétique basée sur des atomes refroidis par laser en vue d'un couplage avec une colonne à faisceaux d'ions focalisés." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00781962.
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Cette thèse porte sur l'étude de la production d'une source d'ionsCes travaux de thèse ont consisté à étudier la faisabilité d'une source d'ions césium brillante et de faible dispersion énergétique à partir d'atomes froids dans le but de la coupler à une optique de faisceau d'ions focalisés (FIB).Il s'agit de produire une source ionique continue, de fort courant et de plus faible dispersion en énergie que les sources actuellement utilisées. Un schéma expérimental innovant a donc été imaginé.Un flux continu d'atomes de césium est issu d'un four à recirculation. Les atomes sont ensuite collimatés et compressés en se basant su les techniques de refroidissement d'atomes par laser. Des simulations de la mélasse optique pour la collimation et du MOT-2D pour la compression sont présentées. Issus d'un jet effusif de césium produit par un four à recirculation, la collimation grâce à une mélasse optique et la compression effectuée en en utilisant un MOT-2D des atomes de césium a été étudiée. Le schéma d'ionisation des atomes de césium passe par une excitation vers un état de Rydberg puis par une ionisation par champ électrique. Les propriétés remarquables des atomes pour ces niveaux d'énergie permettent d'obtenir une ionisation des atomes en champ électrique quasi-instantanée qui permet la minimisation de la dispersion énergétique. Nous avons développer une simulation permettant d'étudier les propriétés du champ électrique nécessaire pour l'ionisation afin de choisir le niveau de Rydberg approprié. Des simulations complémentaires ont permis de définir et de concevoir les électrodes nécessaires à la production du champ électrique d'excitation et d'ionisation. Une première étude des effets coulombiens de la source d'ions lors de l'ionisation des atomes de Rydberg est présentée. Enfin, l'étude théorique du couplage de la source obtenue avec une optique de faisceaux d'ions focalisés est réalisée.Un montage expérimental vient compléter ces diverses études et a permis d'obtenir les premiers résultats.
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Assémat, Frédéric. "Manipulation d'états quantiques de la lumière par l'intermédiaire d'un atome de Rydberg unique." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS016.
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La manipulation d’états non-classiques suscite depuis quelques années un engouement important de la part de la communauté scientifique. Que ce soit sur un plan fondamental ou en vue de potentielles applications par exemple dans les domaines de la métrologie, de la communication, ou de l’information quantique, il est essentiel de préparer des systèmes quantiques dans des états non-classiques et de contrôler leur évolution. Le champ de l’électrodynamique quantique en cavité apparaît comme un cadre expérimental idéal pour étudier l’ingénierie de tels états de la lumière. Il repose sur le couplage fort entre un système à deux niveaux d’une part et un mode du champ électromagnétique d’autre part. Cette thèse présente une nouvelle expérience d’électrodynamique quantique en cavité combinant un jet d’atomes lents préparés dans des états de Rydberg dits « circulaires » et le mode électromagnétique d’une cavité supraconductrice. Ce nouveau dispositif permet une augmentation considérable du temps d’interaction entre l’atome et le champ. Nous présentons dans ce manuscrit les premiers résultats expérimentaux qui en découlent. Premièrement, en exploitant le régime d’interaction résonant entre l’atome et le champ nous avons pu générer un état superposé de type chat de Schrödinger que nous avons caractérisé par ses oscillations de Rabi. Deuxièmement, en se plaçant dans le régime d’interaction dispersif, le long temps d’interaction permet de résoudre le spectre des états habillés du système pour des états du champ contenant jusqu’à 8 photons. Cette résolution a alors pu être exploitée afin de générer des états quantiques du champ comme une superposition de 0 et de 2 photonsThe manipulation of non-classical states is of great interest both from a fundamental perspective but also for their potential applications in domains such as quantum information, quantum communication or metrology. It is then essential to be able to prepare quantum systems in such states and control their evolution. The field of cavity quantum electrodynamics is very well suited to study non-classical states of light. It relies on the strong coupling of a two-level system on one side and one mode of the electromagnetic field on the other side. This thesis introduces a new experiment of cavity quantum electrodynamics combining a beam of slow atoms prepared in Rydberg circular states and the electromagnetic mode of a superconducting cavity. This new set-up allows us to improve significantly the interaction time between the atom and the field. Thanks to this, we obtained our first experimental results that we are presenting in this manuscript. Firstly, we use the resonant interaction between the atom and the field to generate a Schrödinger cat state, superposition of two coherent field of opposite phases. This field is then characterized thanks to its Rabi oscillation signal. Secondly, we make use of the long interaction time in the dispersive regime to achieve a resolution of the dressed state spectrum of the system up to 8 photons. Thanks to this resolution we were finally able to engineer quantum states such as the superposition of 0 and 2 photons
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Ohl, de Mello Daniel [Verfasser], Gerhard [Akademischer Betreuer] Birkl, and Thomas [Akademischer Betreuer] Walther. "Rydberg interactions in a defect-free array of single-atom quantum systems / Daniel Ohl de Mello ; Gerhard Birkl, Thomas Walther." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2020. http://d-nb.info/1207075485/34.
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Giorgi, Javier B. "Surface-aligned photochemistry, photolysis of HX (X = Cl, Br, I, SH) adsorbed on LiF(001), studied by Rydberg-atom time-of-flight spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0016/NQ45656.pdf.
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Abdussalam, Wildan [Verfasser], Jan Michael [Akademischer Betreuer] [Gutachter] Rost, and Walter [Gutachter] Strunz. "Dynamics of Rydberg atom lattices in the presence of noise and dissipation / Wildan Abdussalam ; Gutachter: Jan Michael Rost, Walter Strunz ; Betreuer: Jan Michael Rost." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1139977393/34.
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Abdussalam, Wildan [Verfasser], Jan-Michael [Akademischer Betreuer] Rost, and Walter [Gutachter] Strunz. "Dynamics of Rydberg atom lattices in the presence of noise and dissipation / Wildan Abdussalam ; Gutachter: Jan Michael Rost, Walter Strunz ; Betreuer: Jan Michael Rost." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227485.
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Piotrowicz, Michal J. "Ultracold Rydberg atoms." Thesis, Open University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530495.
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Flynn, Emma L. "Reactive scattering of Rydberg atoms." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2503/.
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A state-of-the-art crossed molecular beam experiment to study the dynamics of bimolecular reactions of electronically highly excited atoms and molecules has been developed. This was primarily designed to investigate the reaction of highly excited Rydberg hydrogen atoms with D(_2) molecules. This reaction is of special interest as it can be compared to the ion-molecule reaction H(^+) + D(_2), using the free electron model and this reaction acts as a benchmark to theoreticians in the quest to understand more complex reactions. The equipment has been calibrated and tested using the well known photodissociation of HI. The initial reactive scattering ion images for H* + D(_2) reaction have been recorded. It was hoped that it would be possible to extract state-to-state differential cross sections; however, to date sufficient resolution has not been achieved, and reasons for this are explored in this study. An overview of the suitability of the prototype molecular wire 1, 4- bis(phenylethynyl)benzene is also included. In this study UV spectra resolving the torsional motion of the benzene rings have been produced using the technique of cavity ring-down spectroscopy.
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Mazurenko, Anton. "Optical imaging of Rydberg atoms." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78519.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 109-111).
We present an experiment exploring electromagnetically induced transparency (EIT) in Rydberg atoms in order to observe optical nonlinearities at the single photon level. ⁸⁷Rb atoms are trapped and cooled using a magneto-optical trap (MOT) and a far off resonance dipole trap (FORT). Once the system is prepared, a ladder EIT scheme with Rydberg atoms is used to map the photon field onto the ensemble. The powerful dipole interaction between Rydberg atoms allows the system to exhibit many-body quantum mechanical effects. We also describe an imaging method to observe the Rydberg blockade. Last of all, we present a preliminary measurement of EIT in a Rydberg system. In this measurement, the transmission shows sensitivity to the applied photon flux, and exhibits temporal correlations in the photons exiting the EIT medium.
by Anton Mazurenko.
S.B.
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Thwaite, Simon James. "Simulations of systems of cold Rydberg atoms." Thesis, University of Oxford, 2012. https://ora.ox.ac.uk/objects/uuid:454e438d-2a3c-4c91-b1d4-2c594cbab2ce.
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The past three decades have seen extraordinary progress in the manipulation of neutral atoms with laser light, to the point where it is now routine to trap and cool both individual atoms and entire atomic clouds to temperatures of only a few tens of nanoKelvin in a controlled and repeatable fashion. In this thesis we study several applications of Rydberg atoms - atoms with an electron in a highly excited state - within such ultracold atomic systems. Due to their highly-excited electron, Rydberg atoms have a number of exaggerated properties: in addition to being physically large, they have long radiative lifetimes, and interact strongly both with one another and with applied external fields. Rydberg atoms consequently find many interesting applications within ultracold atomic physics. We begin this thesis by analysing the way in which a rubidium atom prepared in an excited Rydberg state decays to the ground state. Using quantum defect theory to model the wavefunction of the excited electron, we compute branching ratios for the various decay channels that lead out of the Rydberg states of rubidium. By using these results to carry out detailed simulations of the radiative cascade process, we show that the dynamics of spontaneous emission from Rydberg states cannot be adequately described by a truncated atomic level structure. We then investigate the stability of ultra-large diatomic molecules formed by pairs of Rydberg atoms. Using quantum defect theory to model the electronic wavefunctions, we apply molecular integral techniques to calculate the equilibrium distance and binding energy of these molecular Rydberg states. Our results indicate that these Ryberg macro-dimers are predicted to show a potential minimum, with equilibrium distances of up to several hundred nanometres. In the second half of this thesis, we present a new method of symbolically evaluating functions of matrices. This method, which we term the method of path-sums, has applications to the simulation of strongly-correlated many-body Rydberg systems, and is based on the combination of a mapping between matrix multiplications and walks on weighted directed graphs with a universal result on the structure of such walks. After presenting and proving this universal graph theoretic result, we develop the path-sum approach to matrix functions. We discuss the application of path-sums to the simulation of strongly-correlated many-body quantum systems, and indicate future directions for the method.
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Faoro, Riccardo. "Few-body interactions in cold Rydberg atoms." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS180/document.
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L’objectif de cette thèse est l’étude des différents aspects de l’interaction à quelques corps entre des atomes de Rydberg froids. Cette thèse a été réalisée dans le cadre d’une cotutelle entre l’Université Paris-Saclay et l’Université de Pise en travaillant sur deux différents montages expérimentaux sur des atomes de Rydberg froids : respectivement sur le Cs au Laboratoire Aimé Cotton et sur le Rb au département de Physique de l’Université de Pise. Au Laboratoire Aimé Cotton nous avons démontré l’existence des nouvelles interactions à quelques corps dans un gas gelé d’atomes de Rydberg. Ces nouvelles résonances sont la généralisation des résonances de Förster bien connues dans le domaine des atomes de Rydberg. Ces résonances agissent sur les degrés de liberté interne des atomes de Rydberg et ont l’effet d’un transfert résonant d’énergie et de population comme dans le cas des FRET (Fluorescence Resonance Energy Transfer). Comme dans le cas de la résonance de Förster à deux corps, les résonances FRET à trois corps sont accordées à la résonance avec un champ électrique externe et peuvent être observées pour différents nombres quantique principaux. Les effets à trois corps sont observés en absence de tout effet à deux corps et sont qualifiés de Borroméens. La présence d’un champ externe peut générer d’autres résonances entre atomes de Rydberg qui sont interdites en absence de champ électrique. Ces résonances, qu’on peut qualifier des résonances quasi-interdites, sont dues à un couplage dipole-dipole de type Förster. Nous avons identifié toutes ces résonances liées au couplage entre les niveaux de multiplicité de n différents.Dans le montage expérimental à Pise on a étudié les effets mécaniques liés à la répulsion van der Waals entre atomes de Rydberg. Nous avons étudié l’expansion due à l’interaction van der Waals dans une chaîne 1D des atomes de Rydberg de Rb qui ont étés excités avec une excitation laser hors résonance. La comparaison entre les différents désaccords de l’excitation laser démontre le rôle central joué par l’interaction van der WaalsThe aim of this thesis is to investigate different aspects of few-body interactions in cold Rydberg atoms. It has been realized in a co-tutelle program between the University of Paris-Saclay and the University of Pisa working on two different experimental set ups: one at Laboratoire Aimé Cotton on cold Cs Rydberg atoms and a second at Physics Department of Pisa on cold Rb Rydberg atoms. In Laboratoire Aimé Cotton we demonstrated the existence of new few-body interactions we observed in a frozen Rydberg gas of Cs atoms. These new resonances are a generalization of already known two-body Förster resonances. They act on the internal degrees of freedom of the Rydberg atoms leading to a resonant energy transfer analogous to the one in FRET (Fluorescence Resonance Energy Transfer). In analogy with Förster resonance, three-body FRETs are tuned with an external electric field and can be observed for different principal quantum number. The three-body interaction appeared in the absence of any two-body ones and for this reasons it has a Borromean character. The presence of this external electric field leads to additional resonances between Rydberg atoms supposedly forbidden. These resonances, we call quasi-forbidden Förster resonances, are due to dipole-dipole interaction as in the case of Förster resonance. We investigated these resonances finding a large number close to the allowed two-body and three-body FRET. A precise study was necessary in order to identify and discriminate these resonances from the allowed ones.In the experiment in Pisa we instead focus our attention on the mechanical effect of van der Waals repulsion between Rydberg atoms. We studied the spatial expansion due to a van der Waals interaction in a 1D chain of Rb Rydberg atoms excited with an off-resonant laser excitation. The comparison of the spatial expansion for different detuning of the laser excitation reveals the central role of the van der Waals interaction whose strength is equal to the detuning of the laser excitation
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Caliri, Lucas Larcher. "Processos binários em átomos de Rydberg." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-18062008-113214/.
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O presente trabalho procura investigar alguns dos processos colisionais de átomos de Rydberg ultrafrios. Utilizando uma armadilha magneto-óptica (MOT), foi possível aprisionar átomos de 85Rb, um elemento alcalino metálico, numa região da ordem de lmn a temperaturas da ordem de poucas centenas de ?K, regime chamado de \"ultrafrio\" na literatura. Os átomos de 85Rb são então excitados para estados de alto número quântico principal, também chamados de estados de Rydberg, através de um laser pulsado. Nesses estados, os átomos apresentam propriedades exageradas devido ao tamanho da órbita do elétron de valência, sendo uma delas os potenciais de longo-alcance. Em nossos experimentos, após a excitação, são detectados átomos em estados vizinhos ao originalmente excitado, evidenciando a existência de transições. Como esses estados são muito próximos em energia, a presença de potenciais de longo alcance pode fazer a energia de um par de átomos de Rydberg no seu estado inicial ficar ressonante com a energia do mesmo par numa combinação de outros estados, tornando então possível transições para esses estados. Nosso estudo visa quantificar de certa forma essas observações, assim como estimar a importância do movimento desses átomos nas transições observadas.This dissertation seeks to address some of the characteristics of collisional processes in ultracold Rydberg atoms. With a Maqneto-Optical Trap (MOT), we trapped a sample of 85Rb, an alkaline metal element, in a region of about lmm at a temperature of a few hundreds of ?K, known in the literature as the \"ultracold\" regime. The 85Rb atoms are then excited to high principal quantum number states, also known as Rydberg states, with a pulsed laser. In these states, the atoms present exaggerated properties due to the large valence electron orbit, such as long-range potentials in our experiments, after excitation, we have detected atoms in neighboring states to the originally excited state, an evidence of atomic transitions. Since these states have similar energy, the presence of long-range potentials can make the energy of a pair of atoms in the initial state be resonant with the energy of the same pair in a combination of different states, making it possible to have transitions to these nearby states. Our work tries to quantify these observations, as well as to gauge the role of atomic movement in these transitions.
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Baluktsian, Thomas [Verfasser]. "Rydberg interaction between thermal atoms: Van der Waals-type Rydberg-Rydberg interaction in a vapor cell experiment / Thomas Baluktsian." München : Verlag Dr. Hut, 2014. http://d-nb.info/1047994690/34.
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Paskauskas, Rytis. "Chaotic Scattering in Rydberg Atoms, Trapping in Molecules." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19809.
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We investigate chaotic ionization of highly excited hydrogen atom in crossed electric and magnetic fields (Rydberg atom) and intra-molecular relaxation in planar carbonyl sulfide (OCS) molecule. The underlying theoretical framework of our studies is dynamical systems theory and periodic orbit theory. These theories offer formulae to compute expectation values of observables in chaotic systems with best accuracy available in given circumstances, however they require to have a good control and reliable numerical tools to compute unstable periodic orbits. We have developed such methods of computation and partitioning of the phase space of hydrogen atom in crossed at right angles electric and magnetic fields, represented by a two degree of freedom (dof) Hamiltonian system. We discuss extensions to a 3-dof setting by developing the methodology to compute unstable invariant tori, and applying it to the planar OCS, represented by a 3-dof Hamiltonian. We find such tori important in explaining anomalous relaxation rates in chemical reactions. Their potential application in Transition State Theory is discussed.
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So, Eric. "Interaction of Rydberg hydrogen atoms with metal surfaces." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:53984973-1766-45cc-8bcf-055be714ed73.
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This thesis presents a theoretical and experimental investigation of the interaction of electronically excited Rydberg hydrogen atoms with metal surfaces and the associated charge-transfer process. As a Rydberg atom approaches a metal surface, the energies of the Rydberg states are perturbed by the surface potential generated by the image charges of the Rydberg electron and core. At small atom-surface separations, the Rydberg atom may be ionised by resonant charge transfer of the Rydberg electron to the continuum of delocalised unoccupied metal states, with which the Rydberg electron is degenerate in energy. Typically, this ‘surface ionisation’ can be measured by extracting the remaining positively charged ion-cores with externally applied electric fields. By applying various levels of theory, from classical to fully time-dependent quantum calculations, this thesis explores various experimentally relevant effects on the charge-transfer process, such as the magnitude and direction of the externally applied electric field, the atom collisional velocity, the presence of local surface stray fields and electronically structured surfaces. The theoretical results give insight into the previous experimental work carried out for the xenon atom and hydrogen molecule, and point out some of the fundamental differences from the hydrogen atom system. Experiments involving Rydberg hydrogen atoms incident on an atomically flat gold surface, a rough machined aluminium surface and a single crystal copper (100) surface are presented, providing for the first time the opportunity to make a quantitative comparison of theory and experiments. The ability to control the critical distance at which charge-transfer occurs is demonstrated by using Rydberg states of varying dimensions and collisional velocities. By changing the collisional angle of the incident Rydberg beam, the effect of Rydberg trajectory is also investigated. By manipulating the polarisation of the Rydberg electron with electric fields, genuine control over the orientation of the electron density distribution in the charge-transfer process is demonstrated. This property was predicted by the theory and should be unique to the hydrogen atom due to its intrinsic symmetry. By reversing the direction of the electric field with respect to the metal surface, electrons rather than positive ions are detected, with ionisation dynamics that appear to be very different, as predicted by quantum calculations. Experiments involving the single crystal Cu(100) surface also suggests possible resonance effects from image states embedded in the projected bandgap which are shown from quantum calculations to play an important role in the surface charge transfer of electronically structured metal substrates. The experimental technique developed in this work provides some exciting future applications to study quantum confinement effects with thin films, nanoparticles and other bandgap surfaces. The ability to control the Rydberg orbital size, electronic energy, collisional velocity and orientation in the charge-transfer process will provide novel ways of probing the surface’s electronic and physical structure, as well as being a valuable feature in offering new opportunities for controlling reactive processes at metallic surfaces.
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Waterland, Robert Leonard. "Rydberg atoms in parallel electric and magnetic fields." W&M ScholarWorks, 1986. https://scholarworks.wm.edu/etd/1539623768.
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I have calculated the energy spectrum of a highly excited atom which lies in parallel, static electric and magnetic fields. In parallel fields the Coulomb quantum numbers n and m are still "good" quantum numbers but 1 is not: the calculation is for n = 30, m = 1 atoms.;The eigenvalues were obtained by semi-classical quantisation of first-order classical perturbation theory and have been calculated for a large range of electric and magnetic field strengths. The results are in good agreement with those found from first-order degenerate quantum perturbation theory.;The semi-classical analysis provides a correlation diagram connecting the Stark effect states to those of the diamagnetic effect.
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Zuliani, Alexandre. "Vers la manipulation optique d'atomes ultra-froids d'ytterbium excités dans des états de Rydberg." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS141/document.
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Les propriétés exacerbées des atomes de Rydberg ont permis d'étendre les possibilités offertes par les atomes froids dans la création de gaz d'atomes en très forte interaction, avec des applications notamment en simulations quantiques, dans la physique à N corps ou dans la réalisation de portes quantiques grâce au phénomène de blocage dipolaire. L'utilisation des atomes de Rydberg froids est cependant actuellement limitée par le fait qu'il n'est pas possible de continuer d'appliquer les techniques expérimentales de manipulation optique avec les atomes à un électron actif. L’attention de la communauté des atomes de Rydberg froids s’est donc récemment portée sur les atomes à deux électrons actifs qui offrent la possibilités, une fois l’un des deux électrons excité vers un état de Rydberg, de disposer d’un second électron optiquement actif qu’il va être possible de manipuler par laser. L’objectif de cette thèse est d’étendre les techniques de manipulation optique aux atomes à deux électrons actifs excités dans des états de Rydberg, dans le cas de l’atome d’ytterbium. Elle présente d’une part la conception et l’assemblage du dispositif expérimental permettant l’obtention d’une source d’atomes de Rydberg froids d’ytterbium. A terme, ce montage permettra la manipulation optique de ces atomes de Rydberg. D’autre part, elle présente le développement d’un modèle numérique implémentant la théorie du défaut quantique à plusieurs voies pour permettre la détermination théorique du spectre énergétique de l’ytterbium ainsi que son comportement sous l’effet de perturbations extérieuresThe exacerbated properties of Rydberg atoms have extended the possibilities offered by cold atoms in creating atomic gases in very strong interaction with applications including quantum simulations in many-body physics or in achieving of quantum gates with the dipole blocking phenomenon. The use of cold Rydberg atoms is however currently limited by the fact that it is not possible to continue to apply the experimental techniques of optical manipulation with the atoms to an active electron. The attention of the Rydberg atoms cold community is recently focused on the two active electron atoms offering possibilities, once one of the two electrons excited to a Rydberg state, to provide a second optically active electron that it will be possible to manipulate with laser light.The objective of this thesis is to extend the optical manipulation techniques to atoms with two active electrons excited in Rydberg states, in the case of the ytterbium atom. It has on the one hand the design and assembly of the experimental apparatus for obtaining a source of cold Rydberg ytterbium atoms. Ultimately, this device will allow the optical manipulation of these Rydberg atoms. Furthermore, it presents the development of a numerical model that implements the multichannel quantum defect theory to the theoretical determination of the energy spectrum of ytterbium and its behavior under the influence of external perturbations
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Thoumany, Pierre. "Optical Spectroscopy and Cavity QED Experiments with Rydberg Atoms." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-130845.
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Tignone, Edoardo. "Cavity quantum electrodynamics : from photonic crystals to Rydberg atoms." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF008/document.
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Dans le premier chapitre de la thèse, nous étudions la possibilité d’améliorer le couplage opto- mechanique photon-phonon entre le mode de résonance d’une cavité Fabry-Pérot de haute finesse et les vibrations mécaniques des éléments diélectriques (membranes) à l’intérieur de la cavité. En introduisant un défaut quadratique dans la disposition des membranes, nous montrons que le deux couplages (linéaire et quadratique) augmentent. Enfin, nous proposons un modèle très simple avec lequel on cherche à simuler un cristal photonique quasipériodique. Dans le deuxième chapitre de cette thèse, nous présentons nos résultats de recherche sur le transport d’excitons à travers une cavité visant à augmenter l’efficacité du transport. Le modèle que l’on étudie est une chaîne unidimensionnelle d’atomes froids comprenant chacun deux niveaux énergétiques. Grâce au couplage entre exciton et photon, ces deux quanta s’hybrident et forment deux branches de polariton à l’intérieur de la cavité. Nous avons observé qu’à résonance avec un des deux modes de polariton, on peut transmettre l’exciton via le mode polaritonique dans un temps très court. En outre, le désordre n’affecte la propagation excitonique que de façon algébrique. Dans le troisième chapitre de cette thèse, nous présentons nos résultats de recherche sur la réalisa- tion d’interactions entre photons grâce à la médiation d’atomes ultrafroids piégés dans un réseaux optique unidimensionnelle et placés à l’intérieur d’une fibre à cristaux photoniques. Nous avons détecté un régime dans lequel on peut réaliser le “bunching” photon-photon.Dans le quatrième et dernière chapitre de cette thèse, nous étendons les résultats du chapitre précédent aux atomes de RydbergIn the first chapter of this thesis, we study a quasiperiodic array of dielectric membranes inside a high-finesse Fabry-Pérot cavity. We work within the framework of the transfer matrix formal- ism. We show that, in a transmissive regime, the introduction of a quadratic spatial defect in the membrane positions enhances both the linear and quadratic optomechanical couplings between optical and mechanical degrees of freedom. Finally, we propose a theoretical model to simulate a one-dimensional quasiperiodic photonic crystal. In the second chapter of this thesis, we consider the problem of the transport of an exciton through a one-dimensional chain of two-level systems. We embed the chain of emitters in a transverse optical cavity and we show that, in the strong coupling regime, a ultrafast ballistic transport of the exciton is possible via the polaritonic modes rather than ordinary hopping. Due to the hybrid nature of polaritons, the transport efficiency is particularly robust against disorder and imperfections in the system. In the third chapter of this thesis, we consider an ordered array of cold atoms trapped in an optical lattice inside a hollow-core photonic crystal fiber. We study photon-photon interactions mediated by hard-core repulsion between excitons. We show that, in spite of underlying repulsive interac- tion, photons in the scattering states demonstrate bunching, which can be controlled by tuning the interatomic separation. We interpret this bunching as the result of scattering due to the mismatch of the quantization volumes for excitons and photons, and discuss the dependence of the effect on experimentally relevant parameters. In the fourth chapter of the thesis, we extend the results of the previous chapter to Rydberg atoms
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Busche, Hannes. "Contactless quantum non-linear optics with cold Rydberg atoms." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12238/.
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Rydberg quantum optics achieves optical non-linearities at the single-photon level by mapping the strong dipolar interactions between Rydberg atoms in cold atomic gases onto light fields using electromagnetically-induced transparency and photon storage. The non-linearities are a direct consequence of the long-range character of the interaction which allows a single photon to modify the optical response in a volume containing many atoms. In this thesis, the long-range character of the resulting effective photon-photon interaction is directly observed as photons propagating in non-overlapping optical modes are stored as collective Rydberg excitations in adjacent and non-overlapping microscopic clouds of 87Rb atoms. While stored, van-der-Waals interactions imprint spatially non-uniform phase shifts in the collective excitations. These distort the photons' retrieval modes resulting in anti-correlated retrieval between the original modes. In this first demonstration of contactless effective interactions between photons, these effects are observed between photons separated by more than 15 times their wavelength, well above the optical diffraction limit. This represents a promising step towards the implementation of scalable, multichannel quantum optical devices such as quantum gates. The experiments are enabled by a new, specialised experimental setup centred around a pair of in-vacuo aspheric lenses. These provide optical resolution of order 1 µm to optically trap and address the ensembles separated by distances well below the range of Rydberg interactions. The ensembles are prepared in approximately 100 ms thanks to efficient loading of a magneto-optical trap (MOT) from an atomic beam produced by a 2D MOT. Combined with the ability to recycle the ensembles > 20000 times, effective cycle times exceeding 100 kHz enable the acquisition of large datasets for the analysis of photon statistics within a matter of minutes.
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Fletcher, Robert S. "Three-body recombination and Rydberg atoms in ultracold plasmas." College Park, Md. : University of Maryland, 2008. http://hdl.handle.net/1903/8086.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Butscher, Björn [Verfasser], and Tilman [Akademischer Betreuer] Pfau. "A Rydberg interferometer : from coherent formation of ultralong-range Rydberg molecules to state tomography of Rydberg atoms / Björn Butscher. Betreuer: Tilman Pfau." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2011. http://d-nb.info/1014277388/34.
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Signoles, Adrien. "Manipulations cohérentes d'états de Rydberg elliptiques par dynamique Zénon quantique." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066614/document.
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Dans ce mémoire, nous décrivons la réalisation d'un nouveau montage expérimental permettant de manipuler, à l'aide d'un champ radiofréquence de polarisation bien définie, l'état interne d'un atome de Rydberg à l'intérieur de la multiplicité Stark. Nous avons utilisé ce dispositif pour transférer, avec une efficacité proche de 1, les atomes depuis un niveau de faible moment angulaire, accessible par excitation optique depuis le fondamental, vers le niveau de Rydberg circulaire, de moment angulaire maximal. Nous avons ensuite cherché à induire des dynamiques quantiques nouvelles de l'état de l'atome et mis en évidence la dynamique Zénon quantique dans un système de grande dimension. En appliquant un champ micro-onde bien choisi, on peut restreindre l'évolution atomique induite par le champ radiofréquence à un sous-ensemble des niveaux Stark de la multiplicité. Cette dynamique confinée est très différente d'une dynamique classique, le système évoluant périodiquement vers un état " chat de Schrödinger ". Nous avons expérimentalement observé cette évolution dans l'espace des phases et mesuré la fonction de Wigner de l'atome au moment de l'apparition du chat, démontrant pour la première fois les aspects non-classiques de la dynamique Zénon quantique dans un espace de Hilbert non-trivialIn this manuscript, we describe the realization of a new experimental setupto manipulate with a well-polarized radiofrequency electric field the internal state of aRydberg atom inside the Stark manifold. We used this setup to transfer with a nearly 1efficiency the atoms from a optically-accessible low-m state to the high angular momentumcircular Rydberg state. We then tried to induce new quantum dynamics of the atomicstate and we showed the quantum Zeno dynamics in a large Hilbert space. By applying awell-choose microwave field, one can restrict the atomic evolution induced by the radiofrequencyfield to a subspace of the Stark manifold. This confined dynamics is very differentfrom a classical dynamics. The system periodically evolves to a « Schrödinger cat state ».We experimentally observed this evolution in the phase space and mesured the atomicWigner function at the cat state . This is the first demonstration of the non-classicalaspect of the quantum Zeno dynamics in a non-trivial Hilbert space
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Mukherjee, Rick. "Strong interactions in alkaline-earth Rydberg ensembles." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-157228.
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Ultra-cold atoms in optical lattices provide a versatile and robust platform to study fundamental condensed-matter physics problems and have applications in quantum optics as well as quantum information processing. For many of these applications, Rydberg atoms (atoms excited to large principal quantum numbers) are ideal due to its long coherence times and strong interactions.
However, one of the pre-requisite for such applications is identical confinement of ground state atoms with Rydberg atoms. This is challenging for conventionally used alkali atoms. In this thesis, I discuss the potential of using alkaline-earth Rydberg atoms for many-body physics by implementing simultaneous trapping for the relevant internal states. In particular, I consider a scheme for generating multi-particle entanglement and explore charge transport in a one dimensional atomic lattice.
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Wintermantel, Tobias Martin. "Complex systems dynamics in laser excited ensembles of Rydberg atoms." Thesis, Strasbourg, 2021. http://www.theses.fr/2021STRAE001.
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Dans cette thèse, je présente des résultats expérimentaux et théoriques montrant qu’un gaz ultra-froid sous excitation laser aux états de Rydberg offre une plateforme contrôlable pour l’étude d’une intéressante dynamique complexe qui peut émerger dans les systèmes drivés-dissipatifs. Les conclusions peuvent être résumées selon les trois idées principales suivantes : (i) La découverte de la criticité auto-organisée dans notre système de Rydberg sous excitation facilitée peut aider à répondre à la question suivante : Pourquoi le comportement invariant d’échelle est si répandu dans la nature ? (ii) Un lien frappant est établi entre la croissance de la loi de puissance du nombre d’excitation de Rydberg et la propagation des épidémies. L’importance de l’hétérogénéité dans le réseau Rydberg émergeant et les effets Griffith associés permettent d’expliquer l’observation de lois de puissance non universelles. (iii) Une nouvelle mise en oeuvre d’automates cellulaires quantiques est proposée en utilisant des réseaux atomiques associés à des champs laser multifréquences. Cela fournit un cadre naturel pour étudier la relation entre les processus microscopiques et la dynamique globale, où des règles spéciales sont trouvées pour générer des états enchevêtrés pour des applications en métrologie et en informatique quantiqueIn this thesis I present experimental and theoretical results showing that an ultracold gas under laser excitation to Rydberg states offers a controllable platform for studying the interesting complex dynamics that can emerge in driven-dissipative systems. The findings can be summarized according to the following three main insights: (i) The discovery of self-organized criticality (SOC) in our Rydberg system under facilitated excitation via three signatures: self-organization of the density to a stationary state; scale invariant behavior; and a critical response in terms of power-law distributed excitation avalanches. Additionally, we explore a mechanism inherent to our system which stabilizes the SOC state. We further investigate this stabilization via a controlled, variable driving of the system. These analyses can help answer the question of why scale invariant behavior is so prevalent in nature. (ii) A striking connection between the power-law growth of the Rydberg excitation number and epidemic spreading is found. Based on this, an epidemic network model is devised which efficiently describes the collective excitation dynamics. The importance of heterogeneity in the emergent Rydberg network and associated Griffiths effects provide a way to explain the observation of non-universal power laws.(iii) A novel quantum cellular automata implementation is proposed using atomic arrays together with multifrequency laser fields. This provides a natural framework to study the relation between microscopic processes and global dynamics, where special rules are found to generate entangled states with applications in quantum metrology and computing
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Cantat-Moltrecht, Tigrane. "Atomes de Rydberg en interaction : des nuages denses d'atomes de Rydberg à la simulation quantique avec des atomes circulaires." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEE001/document.
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Les systèmes quantiques à N corps en interaction sont au cœur des problèmes actuels de la recherche en physique quantique. La compréhension de tels systèmes est un enjeu crucial pour le développement des connaissances en physique de la matière condensée. De nombreux efforts de recherche visent à la construction d'un « simulateur quantique » : une plateforme permettant de modéliser, grâce à un système quantique bien contrôlé, un système quantique dont l'accès expérimental est difficile. Les fortes interactions dipolaires entre atomes de Rydberg représentent un objet d'étude choix pour ce type de problème. Nous présentons dans le présent manuscrit une étude des conditions d'excitation d'un nuage dense d'atomes de Rydberg en interaction, permise par le dispositif expérimental dont nous disposons, qui mêle les techniques de piégeage et de refroidissement d’atomes sur puce avec les techniques de manipulation des niveaux de Rydberg. Les résultats de cette étude nous permettent de formuler une proposition expérimentale complète de développement d'un simulateur quantique fondé sur le piégeage d'atomes de Rydberg circulaires. Le simulateur que nous proposons est très prometteur, grâce à sa flexibilité et aux longs temps de simulation qu’il permettrait. Nous terminons ce manuscrit par la description détaillée de la première étape sur le chemin vers ce simulateur : l'excitation d’atomes de Rydberg circulaires sur puceInteracting many-body quantum systems are at the heart of contemporary research in quantum physics. The understanding of such systems is crucial to the development of condensed-matter physics. Many research efforts aim at building a "quantum simulator": a platform which allows to model a hard-to-access quantum system with a more controllable one. Ensembles of Rydberg atoms, thanks to their strong dipolar interactions, make for an excellent system to study many-body quantum physics. We present here a study of the excitation of a dense cloud of interacting Rydberg atoms. This study was conducted on an experimental setup mixing on-chip cold atoms techniques with Rydberg atoms manipulation techniques. The result of this study leads us to make a full-fledged proposal for the realisation of a quantum simulator, based on trapped circular Rydberg atoms. The proposed simulator is particularly promising due to its flexibility and to the long simulation times for which it would allow. We conclude this manuscript with a detailed description of the first experimental step towards building such a simulator: the on-chip excitation of circular Rydberg atoms
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Topçu, Türker. "Time dependent studies of fundamental atomic processes in Rydberg atoms /." Auburn, Ala., 2007. http://repo.lib.auburn.edu/07M%20Dissertations/TOPCU_TURKER_31.pdf.
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Abel, Richard Philip. "Coherent excitation of ultracold atoms between ground and Rydberg states." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/1405/.
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This thesis describes the development of an experiment to study coherent population transfer between ground states, and between ground and Rydberg states, in ultracold atoms. In order to study coherent transfer between hyperfine ground states a pair of phase stable Raman beams is required. Both beams are derived from a single master laser before being spatially separated into individual components using a novel Faraday filtering technique. The frequency dependent Faraday effect in an isotopically pure thermal vapour is exploited to rotate the plane of polarisation of each Raman component such that they may be separated using a polarising beam splitter. The Raman beams are applied to a sample of ultracold atoms and evidence of coherent population transfer is observed. Rydberg states offer an ideal tool for electrometry; the electric field induced Rydberg energy level shift scales with the seventh power of the principle quantum number. Electromagnetically induced transparency (EIT) is used to map Rydberg energy level shifts onto a ground state transition. EIT in a thermal vapour cell also provides a novel method of stabilising the Rydberg coupling laser. The Rydberg energy level shift is highly sensitive to the electric field produced by adsorbates bonded to a nearby dielectric surface. These effects are found to be time dependent and can be eliminated if the electric field is applied transiently. The measured electric field is compared to that calculated by numerical solution of Laplace's equation; the bulk dielectric is found to have a strong effect on the local electric field experienced by the atoms. The exaggerated properties of Rydberg states make these systems ideal for quantum information processing and precision electrometry.
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Hamadeh, Lama. "Ultracold gases of Rydberg-dressed atoms in multi-well traps." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/55953/.
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Rydberg-dressed ground state atoms are atoms with an electron off-resonantly excited to a very high energy state, i.e., a state of high principal quantum number n ≫ 1. This thesis investigates the quantum dynamics of interacting Rydberg-dressed ground state atoms trapped in several multi-well potential traps. Rydberg atoms are atoms with exaggerated properties. One of their most interesting properties is that they exhibit a strong and long-ranged interaction that can be tuned leading to a variety of different quantum behaviours. My work focuses on studying the effects of these interacting atoms when loaded in multi-well potential traps. Generally, multi-well systems are considered as the simplest example of a finite optical lattice structure. For this reason, this thesis covers three research topics that examine the effects of long-range interaction on Rydberg-dressed atoms trapped in several potential confinements. I begin, in the introduction, by discussing the theoretical background of relevance to this work. It starts with presenting the physics of Bose-Einstein condensate. Then, the fundamentals of the interaction between two-level atom and light are analytically studied. This study has the purpose of understanding both; the dressed interacting atoms and optical lattices. The definition, characteristics, and the nature of the interaction between Rydberg atoms are analysed afterwards. The second chapter examines the dynamics of an ensemble of interacting Rydberg- dressed atoms trapped in static, i.e., time-independent, multi-well potentials using a mean-field theoretical approach. I choose one-dimensional double- and triple-well in addition to a two-dimensional quadruple-well potentials. The time-dependent non-linear Gross-Pitaevskii equation is used to numerically explore the ensemble's quantum dynamics. Solving the dynamical differential equations along with tuning the strength of the applied long-range interaction shows that the behaviour of non-interacting Rydberg-dressed atoms does not differ conceptually according to the geometry of the trapping potential. However, this changes when the interactions are switched on where the shape of the confinement leads to interesting outcomes especially in the non-linear interacting limit, such as macroscopic quantum self-trapping. After investigating an ensemble of interacting Rydberg-dressed atoms in static multi-well potential traps, the second research topic examines the dynamical evolution of these atoms when loaded in a finite optical lattice using the extended Bose-Hubbard model. In this chapter, the atoms ensemble is assumed to be in a superfluid state where I investigate both, the order parameter when the Rydberg excitation laser is applied and the interference pattern of the condensates in different dimensions. The study shows the emerging long-range interactions lead to a rapid collapse of the superfluid order parameter and in general allow only for partial revivals. In addition, the interference experiments can directly reveal the interaction between Rydberg-dressed atoms. In the fourth chapter, the dynamics of Rydberg-dressed atoms trapped in a dynamical, i.e., time-dependent, potential confinement is presented. The dynamical trap is constructed such that it begins as a harmonic oscillator and ends as a double- well potential. The analysis investigates an ensemble of contact-interacting atoms via the time-dependent non-linear GP equation.