Journal articles: 'Quantum and relativistic effects'

1

Stefanovich, E. V. "Quantum effects in relativistic decays." International Journal of Theoretical Physics 35, no. 12 (1996): 2539–54. http://dx.doi.org/10.1007/bf02085762.

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Ivanov, A. Yu, P. A. Andreev, and L. S. Kuz'menkov. "Balance equations in semi-relativistic quantum hydrodynamics." International Journal of Modern Physics B 28, no. 21 (2014): 1450132. http://dx.doi.org/10.1142/s021797921450132x.

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Method of the quantum hydrodynamics has been applied in quantum plasmas studies. As the first step in our consideration, derivation of classical semi-relativistic (i.e., described by the Darwin Lagrangian on microscopic level) hydrodynamical equations is given after a brief review of method development. It provides better distinguishing between classic and quantum semi-relativistic effects. Derivation of the classical equations is interesting since it is made by a natural, but not very widespread method. This derivation contains explicit averaging of the microscopic dynamics. Derivation of corresponding quantum hydrodynamic equations is presented further. Equations are obtained in the five-momentum approximation including the continuity equation, Euler and energy balance equations. It is shown that relativistic corrections lead to presence of new quantum terms in expressions for a force field, a work field etc. The semi-relativistic generalization of the quantum Bohm potential is obtained. Quantum part of the energy current, which is an analog of the quantum Bohm potential for the energy evolution equation, is derived. The Langmuir wave dispersion in semi-relativistic quantum plasmas, corresponding to the Darwin Lagrangian, is also considered to demonstrate contribution of semi-relativistic effects on basic plasma phenomenon.

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Hirono, Yuji, Dmitri E. Kharzeev, and Yi Yin. "New quantum effects in relativistic magnetohydrodynamics." Nuclear Physics A 967 (November 2017): 840–43. http://dx.doi.org/10.1016/j.nuclphysa.2017.06.042.

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Apadula, Luca, Esteban Castro-Ruiz, and Časlav Brukner. "Quantum Reference Frames for Lorentz Symmetry." Quantum 8 (August 14, 2024): 1440. http://dx.doi.org/10.22331/q-2024-08-14-1440.

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Since their first introduction, Quantum Reference Frame (QRF) transformations have been extensively discussed, generalising the covariance of physical laws to the quantum domain. Despite important progress, a formulation of QRF transformations for Lorentz symmetry is still lacking. The present work aims to fill this gap. We first introduce a reformulation of relativistic quantum mechanics independent of any notion of preferred temporal slicing. Based on this, we define transformations that switch between the perspectives of different relativistic QRFs. We introduce a notion of &apos;&apos;quantum Lorentz transformations&apos;&apos; and &apos;&apos;superposition of Lorentz boosts&apos;&apos;, acting on the external degrees of freedom of a quantum particle. We analyse two effects, superposition of time dilations and superposition of length contractions, that arise only if the reference frames exhibit both relativistic and quantum-mechanical features. Finally, we discuss how the effects could be observed by measuring the wave-packet extensions from relativistic QRFs.

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Pakzad, Hamid Reza. "Quantum ion–acoustic shock waves in warm dissipative electron–positron–ion plasmas with relativistic ions." Canadian Journal of Physics 89, no. 9 (2011): 961–65. http://dx.doi.org/10.1139/p11-081.

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Propagation of nonlinear quantum ion–acoustic shock waves in dense quantum plasma, whose constituents are electrons, positrons, and positive ions, is investigated using a quantum hydrodynamical model. Moreover, it is assumed that ion velocity is weakly relativistic. Also, we consider the effects of kinematic viscosity among the plasma constituents. By using reductive perturbation method, the Korteweg – de Vries – Burger equation is derived. The effects of relativistic ions, ion temperature, and the quantum Bohm potential on the shock waves are reported in this paper.

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Podhorský, Michal, Lukáš Bučinský, Dylan Jayatilaka, and Simon Grabowsky. "HgH2 meets relativistic quantum crystallography. How to teach relativity to a non-relativistic wavefunction." Acta Crystallographica Section A Foundations and Advances 77, no. 1 (2021): 54–66. http://dx.doi.org/10.1107/s2053273320014837.

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The capability of X-ray constrained wavefunction (XCW) fitting to introduce relativistic effects into a non-relativistic wavefunction is tested. It is quantified how much of the reference relativistic effects can be absorbed in the non-relativistic XCW calculation when fitted against relativistic structure factors of a model HgH2 molecule. Scaling of the structure-factor sets to improve the agreement statistics is found to introduce a significant systematic error into the XCW fitting of relativistic effects.

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Ballesteros, Angel, Giulia Gubitosi, and Flavio Mercati. "Interplay between Spacetime Curvature, Speed of Light and Quantum Deformations of Relativistic Symmetries." Symmetry 13, no. 11 (2021): 2099. http://dx.doi.org/10.3390/sym13112099.

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Recent work showed that κ-deformations can describe the quantum deformation of several relativistic models that have been proposed in the context of quantum gravity phenomenology. Starting from the Poincaré algebra of special-relativistic symmetries, one can toggle the curvature parameter Λ, the Planck scale quantum deformation parameter κ and the speed of light parameter c to move to the well-studied κ-Poincaré algebra, the (quantum) (A)dS algebra, the (quantum) Galilei and Carroll algebras and their curved versions. In this review, we survey the properties and relations of these algebras of relativistic symmetries and their associated noncommutative spacetimes, emphasizing the nontrivial effects of interplay between curvature, quantum deformation and speed of light parameters.

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HAAS, F. "Wave dispersion derived from the square-root Klein–Gordon–Poisson system." Journal of Plasma Physics 79, no. 4 (2013): 371–76. http://dx.doi.org/10.1017/s0022377813000044.

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AbstractRecently, there has been great interest around quantum relativistic models for plasmas. In particular, striking advances have been obtained by means of the Klein–Gordon–Maxwell system, which provides a first-order approach to the relativistic regimes of quantum plasmas. The Klein–Gordon–Maxwell system provides a reliable model as long as the plasma spin dynamics is not a fundamental aspect, to be addressed using more refined (and heavier) models involving the Pauli–Schrödinger or Dirac equations. In this work, a further simplification is considered, tracing back to the early days of relativistic quantum theory. Namely, we revisit the square-root Klein–Gordon–Poisson system, where the positive branch of the relativistic energy–momentum relation is mapped to a quantum wave equation. The associated linear wave propagation is analyzed and compared with the results in the literature. We determine physical parameters where the simultaneous quantum and relativistic effects can be noticeable in weakly coupled electrostatic plasmas.

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Siddique, M., M. Jamil, A. Rasheed, F. Areeb, Asif Javed, and P. Sumera. "Impact of Relativistic Electron Beam on Hole Acoustic Instability in Quantum Semiconductor Plasmas." Zeitschrift für Naturforschung A 73, no. 2 (2018): 135–41. http://dx.doi.org/10.1515/zna-2017-0275.

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AbstractWe studied the influence of the classical relativistic beam of electrons on the hole acoustic wave (HAW) instability exciting in the semiconductor quantum plasmas. We conducted this study by using the quantum-hydrodynamic model of dense plasmas, incorporating the quantum effects of semiconductor plasma species which include degeneracy pressure, exchange-correlation potential and Bohm potential. Analysis of the quantum characteristics of semiconductor plasma species along with relativistic effect of beam electrons on the dispersion relation of the HAW is given in detail qualitatively and quantitatively by plotting them numerically. It is worth mentioning that the relativistic electron beam (REB) stabilises the HAWs exciting in semiconductor (GaAs) degenerate plasma.

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Kumar, H., M. Aggarwal, Richa, and T. S. Gill. "Combined effect of relativistic and ponderomotive nonlinearity on self-focusing of Gaussian laser beam in a cold quantum plasma." Laser and Particle Beams 34, no. 3 (2016): 426–32. http://dx.doi.org/10.1017/s0263034616000276.

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AbstractIn the present paper, we have investigated self-focusing of Gaussian laser beam in relativistic ponderomotive (RP) cold quantum plasma. When de Broglie wavelength of charged particles is greater than or equal to the inter particle distance or equivalently the temperature is less than or equal to the Fermi temperature, quantum nature of the plasma constituents cannot be ignored. In this context, we have reported self-focusing on account of nonlinear dielectric contribution of RP plasma by taking into consideration the impact of quantum effects. We have setup the nonlinear differential equation for the beam-width parameter by paraxial ray and Wentzel Kramers Brillouin approximation and solved it numerically by the Runge Kutta Fourth order method. Our results show that additional self-focusing is achieved in case of RP cold quantum plasma than relativistic cold quantum plasma and classical relativistic case. The pinching effect offered by quantum plasma and the combined effect of relativistic and ponderomotive nonlinearity greatly enhances laser propagation up to 20 Rayleigh lengths.

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Ziefle, Reiner Georg. "Newtonian quantum gravity." Physics Essays 33, no. 1 (2020): 99–113. http://dx.doi.org/10.4006/0836-1398-33.1.99.

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Newtonian Quantum Gravity (NQG) unifies quantum physics with Newton's theory of gravity and calculates the so-called “general relativistic” phenomena more precisely and in a much simpler way than General Relativity, whose complicated theoretical construct is no longer needed. Newton's theory of gravity is less accurate than Albert Einstein's theory of general relativity. Famous examples are the precise predictions of General Relativity at binary pulsars. This is the reason why relativistic physicists claim that there can be no doubt that Einstein's theory of relativity correctly describes our physical reality. With the example of the famous “Hulse-Taylor binary” (also known as PSR 1913 + 16 or PSR B1913 + 16), the author proves that the so-called “general relativistic phenomena” observed at this binary solar system can be calculated without having any knowledge on relativistic physics. According to philosophical and epistemological criteria, this should not be possible, if Einstein's theory of relativity indeed described our physical reality. Einstein obviously merely developed an alternative method to calculate these phenomena without quantum physics. The reason was that in those days quantum physics was not yet generally taken into account. It is not the first time that a lack of knowledge of the underlying physical phenomena has to be compensated by complicated mathematics. Einstein's theory of general relativity indirectly already includes additional quantum physical effects of gravitation. This is the reason why it cannot be possible to unite Einstein's theory of general relativity with quantum physics, unless one uses “mathematical tricks” that make the additional quantum physical effects disappear again in the end.

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Loriani, Sina, Alexander Friedrich, Christian Ufrecht, et al. "Interference of clocks: A quantum twin paradox." Science Advances 5, no. 10 (2019): eaax8966. http://dx.doi.org/10.1126/sciadv.aax8966.

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The phase of matter waves depends on proper time and is therefore susceptible to special-relativistic (kinematic) and gravitational (redshift) time dilation. Hence, it is conceivable that atom interferometers measure general-relativistic time-dilation effects. In contrast to this intuition, we show that (i) closed light-pulse interferometers without clock transitions during the pulse sequence are not sensitive to gravitational time dilation in a linear potential. (ii) They can constitute a quantum version of the special-relativistic twin paradox. (iii) Our proposed experimental geometry for a quantum-clock interferometer isolates this effect.

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Kumar, Punit, and Nisha Singh Rathore. "Laser beam guiding in partially stripped magnetized quantum plasma." Laser Physics 32, no. 1 (2021): 016002. http://dx.doi.org/10.1088/1555-6611/ac3ee7.

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Abstract Relativistic and ponderomotive nonlinearities arising by the passage of a linearly polarized laser beam through a partially stripped magnetized quantum plasma are analyzed. The interaction formalism has been developed using the recently developed quantum hydrodynamic model. The effects associated with the Fermi pressure, quantum Bohm potential and electron spin have been incorporated. A nonparaxial, non-linear wave equation has been obtained by the use of source dependent expansion technique and spot size has been evaluated. The nonlinear relativistic self-focusing tends to focus the beam while the ponderomotive nonlinearity tends to defocus. The effect of magnetization and quantum effects on the spot size and the beam power have been studied.

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Ziefle, Reiner Georg. "Newtonian quantum gravity and the derivation of the gravitational constant G and its fluctuations." Physics Essays 33, no. 4 (2020): 387–94. http://dx.doi.org/10.4006/0836-1398-33.4.387.

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The theory of gravity “Newtonian quantum gravity” (NQG) is an ingeniously simple theory, because it precisely predicts so-called “general relativistic phenomena,” as, for example, that observed at the binary pulsar PSR B1913 + 16, by just applying Kepler’s second law on quantized gravitational fields. It is an irony of fate that the unsuspecting relativistic physicists still have to effort with the tensor calculations of an imaginary four-dimensional space-time. Everybody can understand that a mass that moves through space must meet more “gravitational quanta” emitted by a certain mass, if it moves faster than if it moves slower or rests against a certain mass, which must cause additional gravitational effects that must be added to the results of Newton's theory of gravity. However, today's physicists cannot recognize this because they are caught in Einstein's relativistic thinking and as general relativity can coincidentally also predict these quantum effects by a mathematically defined four-dimensional curvature of space-time. Advanced NQG is also able to derive the gravitational constant G and explains why G must fluctuate. The “string theory” tries to unify quantum physics with general relativity, but as the so-called “general relativistic” phenomena are quantum physical effects, it cannot be a realistic theory. The “energy wave theory” is lead to absurdity by the author.

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15

Foo, Joshua, and Magdalena Zych. "Superpositions of thermalisations in relativistic quantum field theory." Quantum 9 (February 11, 2025): 1629. https://doi.org/10.22331/q-2025-02-11-1629.

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Recent results in relativistic quantum information and quantum thermodynamics have independently shown that in the quantum regime, a system may fail to thermalise when subject to quantum-controlled application of the same, single thermalisation channel. For example, an accelerating system with fixed proper acceleration is known to thermalise to an acceleration-dependent temperature, known as the Unruh temperature. However, the same system in a superposition of spatially translated trajectories that share the same proper acceleration fails to thermalise. Here, we provide an explanation of these results using the framework of quantum field theory in relativistic noninertial reference frames. We show how a probe that accelerates in a superposition of spatial translations interacts with incommensurate sets of field modes. In special cases where the modes are orthogonal (for example, when the Rindler wedges are translated in a direction orthogonal to the plane of motion), thermalisation does indeed result, corroborating the here provided explanation. We then discuss how this description relates to an information-theoretic approach aimed at studying quantum aspects of temperature through quantum-controlled thermalisations. The present work draws a connection between research in quantum information, relativistic physics, and quantum thermodynamics, in particular showing that relativistic quantum effects can provide a natural realisation of quantum thermodynamical scenarios.

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Sobhani, Hadi, Won Sang Chung, and Hassan Hassanabadi. "q-Deformed Relativistic Fermion Scattering." Advances in High Energy Physics 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/9530874.

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In this article, after introducing a kind ofq-deformation in quantum mechanics, first,q-deformed form of Dirac equation in relativistic quantum mechanics is derived. Then, three important scattering problems in physics are studied. All results have satisfied what we had expected before. Furthermore, effects of all parameters in the problems on the reflection and transmission coefficients are calculated and shown graphically.

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Mahajan, Ranju, Richa, Tarsem Singh Gill, Ravinder Kaur, and Munish Aggarwal. "Stability and dynamics of a cosh-Gaussian laser beam in relativistic thermal quantum plasma." Laser and Particle Beams 36, no. 3 (2018): 341–52. http://dx.doi.org/10.1017/s0263034618000277.

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AbstractThis paper presents an investigation on the self-focusing of a cosh-Gaussian laser beam in the thermal quantum plasma (TQP) by taking into account the effects of relativistic nonlinearity. An appropriate nonlinear Schrödinger equation has been solved analytically by applying the variational approach. The self-focusing and the self-phase modulation are examined under a variety of parameters. The self-trapping of a cosh-Gaussian laser beam is further studied at various values of the decentered parameter, b with different absorption levels, ${k}^{\prime}_i$. Numerical analysis shows that these parameters play a vital role in propagation characteristics. The significant contribution of the quantum effects to enhance the self-focusing and minimize the longitudinal phase has been observed. Further, a comparison has been made with the classical relativistic (CR), the relativistic cold quantum (RCQ), and the thermal quantum (TQ) regimes. The self-focusing is found to occur earlier and is strongest for the case of TQP in the present analysis.

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TANJIA, FATEMA, RENATO FEDELE, SERGIO DE NICOLA, DUSAN JOVANOVIĆ, and ABDUL MANNAN. "The quantum plasma lens concept: A preliminary investigation." Journal of Plasma Physics 79, no. 4 (2013): 421–27. http://dx.doi.org/10.1017/s0022377813000469.

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AbstractRecently, a theoretical investigation of the collective and nonlocal quantum effects has been carried out within the framework of a quantum approach to the relativistic charged particle beam travelling in a cold, collisionless, strongly magnetized plasma. This has been done taking into account both the plasma wake field excitation and the quantum paraxial approximation. On the basis of this theory, here we carry out a preliminary study of the transverse effects experienced by a cold relativistic beam through a thin plasma slab (plasma lens). In the strongly nonlocal regime, in which the beam experiences a very strong focusing effect, the scheme of plasma lens is reviewed in terms of the wave description provided by the above quantum theory.

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JOSHI, PANKAJ S., and SONAL S. JOSHI. "QUANTUM EFFECTS NEAR SPACETIME SINGULARITIES." Modern Physics Letters A 02, no. 12 (1987): 913–20. http://dx.doi.org/10.1142/s0217732387001166.

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We incorporate quantum effects into the gravitational dynamics in the vicinity of singularity in the case of three important general relativistic spacetimes, namely the spherically symmetric dust-ball collapse, standard Friedmann models and a general cosmological scenario given by Belinskii et al. The quantum state of the universe is represented by a general wave function where the conformal degree of freedom is quantised. It is seen in each case that the spread around the classical state diverges in the limit of approach to the classically singular epoch. Thus, non-classical, non-singular states can occur with finite probability. Our results show that including quantum effects radically changes the usual singularity scenario.

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Fiscaletti, D. "The Geometrodynamic Nature of the Quantum Potential." Ukrainian Journal of Physics 57, no. 5 (2012): 560. http://dx.doi.org/10.15407/ujpe57.5.560.

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The de Broglie–Bohm theory allows us to have got a satisfactory geometrodynamic interpretation of quantum mechanics. The fundamental element, which creates a geometrodynamic picture of the quantum world in the non-relativistic domain, a relativistic curved space-time background, and the quantum gravity domain, is the quantum potential. It is shown that, in the non-relativistic domain, the geometrodynamic nature of the quantum potential followsfrom the fact that it is an information potential containing a space-like active information on the environment; the geometric properties of the space expressed by the quantum potential determine non-local correlations between subatomic particles. Moreover, in the de Broglie–Bohm theory in a curved space-time, it is shown that the quantum, as well as the gravitational, effects of matter have geometric nature and are highly related: the quantum potential can be interpreted as the conformal degree of freedom of the space-time metric, and its presence is equivalent to the curved space-time. It is shown on the basis of some recent research that, in quantum gravity, we have a generalized geometric unification of gravitational and quantum effects of matter; Bohm's interpretation shows that the form of a quantum potential and its relation to the conformal degree of freedom of the space-time metric can be derived from the equations of motion.

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Bakke, K., and H. Belich. "Relativistic geometric quantum phases from the Lorentz symmetry violation effects in the CPT-even gauge sector of Standard Model Extension." International Journal of Modern Physics A 30, no. 33 (2015): 1550197. http://dx.doi.org/10.1142/s0217751x15501973.

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We discuss the appearance of geometric quantum phases for a Dirac neutral particle in the context of relativistic quantum mechanics based on possible scenarios of the Lorentz symmetry violation tensor background in the CPT-even gauge sector of Standard Model Extension. We assume that the Lorentz symmetry breaking is determined by a tensor background given by [Formula: see text], then, relativistic analogues of the Anandan quantum phase [J. Anandan, Phys. Lett. A 138, 347 (1989)] are obtained based on the parity-even and parity-odd sectors of the tensor [Formula: see text].

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Belich, H., and K. Bakke. "Geometric relativistic phase from Lorentz symmetry breaking effects in the cosmic string spacetime." International Journal of Modern Physics D 25, no. 09 (2016): 1641003. http://dx.doi.org/10.1142/s0218271816410030.

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In this paper, we have investigated the arising of geometric quantum phases in a relativistic quantum dynamics of a Dirac neutral particle from the spontaneous Lorentz symmetry violation effects in the cosmic string spacetime. We started by the Dirac equation in an effective metric, and we have observed a relativistic geometric phase which stems from the topology of the cosmic string spacetime and an intrinsic Lorentz symmetry breaking effects. It is shown that both Lorentz symmetry breaking effects and the topology of the defect yields a phase shift in the wave function of the nonrelativistic spin-[Formula: see text] particle.

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Zych, M., I. Pikovski, F. Costa, and Č. Brukner. "General relativistic effects in quantum interference of “clocks”." Journal of Physics: Conference Series 723 (June 2016): 012044. http://dx.doi.org/10.1088/1742-6596/723/1/012044.

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Schwerdtfeger, Peter, Lukáš F. Pašteka, Andrew Punnett, and Patrick O. Bowman. "Relativistic and quantum electrodynamic effects in superheavy elements." Nuclear Physics A 944 (December 2015): 551–77. http://dx.doi.org/10.1016/j.nuclphysa.2015.02.005.

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Zych, Magdalena, Fabio Costa, Igor Pikovski, Timothy C. Ralph, and Časlav Brukner. "General relativistic effects in quantum interference of photons." Classical and Quantum Gravity 29, no. 22 (2012): 224010. http://dx.doi.org/10.1088/0264-9381/29/22/224010.

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Bellini, Mauricio. "Inflationary back-reaction effects from Relativistic Quantum Geometry." Physics of the Dark Universe 11 (March 2016): 64–67. http://dx.doi.org/10.1016/j.dark.2015.12.003.

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Andreev, Pavel A. "NLSE for quantum plasmas with the radiation damping." Modern Physics Letters B 30, no. 13 (2016): 1650180. http://dx.doi.org/10.1142/s0217984916501803.

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We consider contribution of the radiation damping in the quantum hydrodynamic (QHD) equations for spinless particles. We discuss possibility of obtaining corresponding nonlinear Schrödinger equation (NLSE) for the macroscopic wave function. We compare contribution of the radiation damping with weakly (or semi-) relativistic effects appearing in the second-order on [Formula: see text]. The radiation damping appears in the third-order on [Formula: see text]. So it might be smaller than weakly relativistic effects, but it gives damping of the Langmuir waves which can be considerable.

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Loret, Niccoló, Stjepan Meljanac, Flavio Mercati, and Danijel Pikutić. "Vectorlike deformations of relativistic quantum phase-space and relativistic kinematics." International Journal of Modern Physics D 26, no. 11 (2017): 1750123. http://dx.doi.org/10.1142/s0218271817501231.

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We study a family of noncommutative spacetimes constructed by one four-vector. The large set of coordinate commutation relations described in this way includes many cases that are widely studied in the literature. The Hopf-algebra symmetries of these noncommutative spacetimes, as well as the structures of star product and twist are introduced and considered at first order in the deformation, described by four parameters. We also study the deformations to relativistic kinematics implied by this framework, and calculate the most general expression for the momentum dependence of the Lorentz transformations on momenta, which is an effect that is required by consistency. At the end of the paper we analyse the phenomenological consequences of this large family of vectorlike deformations on particles propagation in spacetime. This leads to a set of characteristic phenomenological effects.

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Rusakova, Irina L., and Yuriy Yu Rusakov. "Relativistic Effects from Heavy Main Group p-Elements on the NMR Chemical Shifts of Light Atoms: From Pioneering Studies to Recent Advances." Magnetochemistry 9, no. 1 (2023): 24. http://dx.doi.org/10.3390/magnetochemistry9010024.

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This review represents a compendium of computational studies of relativistic effects on the NMR chemical shifts of light nuclei caused by the presence of heavy main group p-block elements in molecules. The narration starts from a brief discussion of the relativistic theories and quantum chemical methods for the calculation of NMR chemical shifts at the relativistic level of the electronic theory. The main part of the review contains a survey on the relativistic calculations of NMR shielding constants of the most popular NMR-active light nuclei such as 1H, 13C, 19F, 29Si, 15N, and 31P of compounds containing heavy p-elements. A special focus is placed on the relativistic effects initiated by the 16th and 17th group elements. Different factors governing the behavior of the relativistic effects on the chemical shifts of light atoms are discussed. In particular, the stereochemistry of the relativistic “heavy atom on the light atom” effect and the influence of the spin–orbit relativistic effects on the vibrational contributions to the shielding constants of light nuclei are considered.

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YAMAMOTO, KUNIO. "DIFFICULTY OF BOUND STATE PROBLEMS IN RELATIVISTIC QUANTUM FIELD THEORY." Modern Physics Letters A 13, no. 02 (1998): 87–89. http://dx.doi.org/10.1142/s0217732398000127.

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In the previous paper, it has been pointed out that, for any model with real bound state in relativistic quantum field theory, Feynman rules do not give the physical amplitude in which the effects of real bound state are considered. By investigating this fact, it is found that an important guiding principle indispensable to discuss real bound state problems is unknown. The way to investigate this principle is not within the framework of relativistic quantum field theory.

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Ismail-Sutton, Sara, Markus Scholle, and Philip H. Gaskell. "Non-Relativistic and Relativistic Lagrangian Pairing in Fluid Mechanics Inspired by Quantum Theory." Symmetry 17, no. 3 (2025): 315. https://doi.org/10.3390/sym17030315.

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The pairing of non-relativistic and relativistic Lagrangians within the context of fluid mechanics, advancing methodologies for constructing Poincare-invariant Lagrangians, is explored. Through leveraging symmetries and Noether’s theorem in an inverse framework, three primary cases are investigated: potential flow, barotropic flow expressed in terms of Clebsch variables, and an extended Clebsch Lagrangian incorporating thermodynamic effects. To ensure physical correctness, the eigenvalue relation of the energy–momentum tensor, together with velocity normalisation, are applied as key criteria. The findings confirm that the relativistic Lagrangians successfully reduce to their non-relativistic counterparts in the limit c→∞. These results demonstrate a systematic approach that enhances the relationship between symmetries and variational formulations, providing the advantage of deriving Lagrangians that unify non-relativistic and relativistic theories.

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CAMELIA, GIOVANNI AMELINO. "ON LOCAL OBSERVATIONS IN QUANTUM GRAVITY." Modern Physics Letters A 11, no. 17 (1996): 1411–16. http://dx.doi.org/10.1142/s0217732396001417.

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By taking into account both quantum mechanical and general relativistic effects, we derive an equation that describes limitations on the measurability of spacetime distances as defined by a material reference system.

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KIM, Kyung Taec. "Relativistic Laser-Plasma Interaction and Nonlinear Quantum Electrodynamics Research Using Ultra-Intense Laser." Physics and High Technology 34, no. 4 (2025): 2–6. https://doi.org/10.3938/phit.34.008.

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We introduce recent research trends in relativistic laser-plasma interactions and nonlinear quantum electrodynamics (QED) research and the research plan of the Center for Relativistic Laser Science (CoReLS) of the Institute for Basic Science (IBS). We aim to experimentally demonstrate relativistic laser-plasma interactions and strong-field QED effects using the CoReLS 4 PW laser. These efforts are expected to deepen our understanding of extreme physical conditions and open new frontiers in high-field science and fundamental physics.

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BEHERA, HARIHAR, and P. C. NAIK. "GRAVITOMAGNETIC MOMENTS AND DYNAMICS OF DIRAC (SPIN ½) FERMIONS IN FLAT SPACE–TIME MAXWELLIAN GRAVITY." International Journal of Modern Physics A 19, no. 25 (2004): 4207–29. http://dx.doi.org/10.1142/s0217751x04017768.

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The gravitational effects in the relativistic quantum mechanics are investigated in a relativistically derived version of Heaviside's speculative gravity (in flat space–time) named here as "Maxwellian gravity." The standard Dirac's approach to the intrinsic spin in the fields of Maxwellian gravity yields the gravitomagnetic moment of a Dirac (spin ½) particle exactly equal to its intrinsic spin. Violation of the Equivalence Principle (both at classical and quantum-mechanical level) in the relativistic domain has also been reported in this work.

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Eser, Selda, and Leyla Özdemir. "Electric dipole transitions between low-lying levels in doubly ionized krypton, xenon, and radon." Canadian Journal of Physics 96, no. 6 (2018): 664–71. http://dx.doi.org/10.1139/cjp-2017-0238.

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Using the general-purpose relativistic atomic structure package (GRASP) based on a fully relativistic multiconfiguration Dirac–Fock (MCDF) method, the transition parameters, such as transition rates (probabilities), oscillator strengths, and line strengths for the electric dipole transitions between low-lying levels are evaluated for doubly ionized krypton, xenon, and radon. Breit interactions for relativistic effects and quantum electrodynamical (QED) contributions besides valence and valence–core correlation effects are taken into account in calculations. We compare the results obtained with the available data in the literature and discuss them, when possible.

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Oleynichenko, Alexander V., Andréi Zaitsevskii, Nikolai S. Mosyagin, Alexander N. Petrov, Ephraim Eliav, and Anatoly V. Titov. "LIBGRPP: A Library for the Evaluation of Molecular Integrals of the Generalized Relativistic Pseudopotential Operator over Gaussian Functions." Symmetry 15, no. 1 (2023): 197. http://dx.doi.org/10.3390/sym15010197.

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Generalized relativistic pseudopotentials (GRPP) of atomic cores implying the use of different potentials for atomic electronic shells with different principal quantum numbers give rise to accurate and reliable relativistic electronic structure models of atoms, molecules, clusters, and solids. These models readily incorporate the effects of Breit electron–electron interactions and one-loop quantum electrodynamics effects. Here, we report the computational procedure for evaluating one-electron integrals of GRPP over contracted Gaussian functions. This procedure was implemented in a library of routines named LIBGRPP, which can be integrated into existing quantum chemistry software, thus enabling the application of various methods to solve the many-electron problem with GRPPs. Pilot applications to electronic transitions in the ThO and UO2 molecules using the new library and intermediate-Hamiltonian Fock space relativistic coupled cluster method are presented. Deviations of excitation energies obtained within the GRPP approach from their all-electron Dirac–Coulomb–Gaunt counterparts do not exceed 50 cm−1 for the 31 lowest-energy states of ThO and 110 cm−1 for the 79 states of UO2. The results clearly demonstrate that rather economical tiny-core GRPP models can exceed in accuracy relativistic all-electron models defined by Dirac–Coulomb and Dirac–Coulomb–Gaunt Hamiltonians.

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Arzano, Michele. "Decoherence and discrete symmetries in deformed relativistic kinematics." EPJ Web of Conferences 166 (2018): 00008. http://dx.doi.org/10.1051/epjconf/201816600008.

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Models of deformed Poincaré symmetries based on group valued momenta have long been studied as effective modifications of relativistic kinematics possibly capturing quantum gravity effects. In this contribution we show how they naturally lead to a generalized quantum time evolution of the type proposed to model fundamental decoherence for quantum systems in the presence of an evaporating black hole. The same structures which determine such generalized evolution also lead to a modification of the action of discrete symmetries and of the CPT operator. These features can in principle be used to put phenomenological constraints on models of deformed relativistic symmetries using precision measurements of neutral kaons.

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AMELINO-CAMELIA, GIOVANNI. "LIMITS ON THE MEASURABILITY OF SPACE-TIME DISTANCES IN (THE SEMICLASSICAL APPROXIMATION OF) QUANTUM GRAVITY." Modern Physics Letters A 09, no. 37 (1994): 3415–22. http://dx.doi.org/10.1142/s0217732394003245.

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By taking into account both quantum mechanical and general relativistic effects, an equation that describes some limitations on the measurability of space-time distances can be derived. We then discuss possible features of quantum gravity which are suggested by this equation.

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Bučinský, Lukáš, Dylan Jayatilaka, and Simon Grabowsky. "Relativistic quantum crystallography of diphenyl- and dicyanomercury. Theoretical structure factors and Hirshfeld atom refinement." Acta Crystallographica Section A Foundations and Advances 75, no. 5 (2019): 705–17. http://dx.doi.org/10.1107/s2053273319008027.

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Quantum crystallographic refinement of heavy-element-containing compounds is a challenge, because many physical effects have to be accounted for adequately. Here, the impact and magnitude of relativistic effects are compared with those of electron correlation, polarization through the environment, choice of basis set and treatment of thermal motion effects on the structure factors of diphenylmercury(II) [Hg(Ph)2] and dicyanomercury(II) [Hg(CN)2]. Furthermore, the individual atomic contributions to the structure factors are explored in detail (using Mulliken population analysis and the exponential decay of atomic displacement parameters) to compare the contributions of lighter atoms, especially hydrogen atoms, against mercury. Subsequently, relativistic Hirshfeld atom refinement (HAR) is validated against theoretical structure factors of Hg(Ph)2 and Hg(CN)2, starting from perturbed geometries, to test if the relativistic variant of HAR leads to multiple solutions. Generally, relativistic HAR is successful, leading to a perfect match with the reference geometries, but some limitations are pointed out.

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Ho, Chiu Man, and Stephen D. H. Hsu. "Locality and nonlinear quantum mechanics." International Journal of Modern Physics A 30, no. 04n05 (2015): 1550029. http://dx.doi.org/10.1142/s0217751x15500293.

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Nonlinear modifications of quantum mechanics generically lead to nonlocal effects which violate relativistic causality. We study these effects using the functional Schrödinger equation for quantum fields and identify a type of nonlocality which causes nearly instantaneous entanglement of spacelike separated systems. We describe a simple example involving widely separated wave packet (coherent) states, showing that nonlinearity in the Schrödinger evolution causes spacelike entanglement, even in free field theory.

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Prokhorov, Georgy, Oleg Teryaev, and Valentin Zakharov. "Calculation of Acceleration Effects Using the Zubarev Density Operator." Particles 3, no. 1 (2020): 1–14. http://dx.doi.org/10.3390/particles3010001.

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The relativistic form of the Zubarev density operator can be used to study quantum effects associated with acceleration of the medium. In particular, it was recently shown that the calculation of perturbative corrections in acceleration based on the Zubarev density operator makes it possible to show the existence of the Unruh effect. In this paper, we present the details of the calculation of quantum correlators arising in the fourth order of the perturbation theory needed to demonstrate the Unruh effect. Expressions for the quantum corrections for massive fermions are also obtained.

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Orlik, Marek. "NOWOCZESNE SPOJRZENIE NA KONFIGURACJE ELEKTRONOWE I UKŁAD OKRESOWY PIERWIASTKÓW, CZYLI O EFEKTACH RELATYWISTYCZNYCH W CHEMII." Wiadomości Chemiczne 77, no. 9 (2023): 833–71. https://doi.org/10.53584/wiadchem.2023.09.2.

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The article describes in an accessible, conceptual way various types of relativistic effects, which are an important part of modern chemical education, practically absent in textbooks, however allowing for a better understanding of the properties of chemical elements and their compounds. This description was preceded by a concise non-relativistic characterization of electrons in multi-electron atoms, in terms of radial probability densities, in order to explain the dependence of electron energies on the principal (n) and orbital (l) quantum numbers. The results of recent quantum chemical calculations are discussed, which show the improved energy sequence of ns and (n-1)d orbitals in transition elements and explain the electron configurations of both neutral atoms and cations of the 3d and 4d block elements. The description of the relativistic effects begins with early Dirac concept of spin- orbit coupling as causing the splitting of the degenerate p, d and f orbitals for two sets of spinors. The role of this splitting in the stability of the respective oxidation states of the cations is discussed. Another important type of relativistic effects, confirmed only in the 1970s, operates in atoms of high nuclear charge (starting from 6. period) in which electrons move at a speed close to the speed of light. The resulting relativistic increase in the mass of the moving electron causes the stabilization of s and p orbitals, and destabilization of d and f orbitals. Representative examples of the influence of all relativistic effects on the properties of elements and their compounds are given (including mercury liquidity or the color of gold). In particular, relativistic effects specific for blocks 5d, 6p, 4f, 5f, 6d, and 7p were discussed. The possibilities of predicting further expansion of the periodic table with elements up to the atomic number of about 170 are outlined, based on taking into account both the relativistic effects for electrons and the stability of superheavy atomic nuclei. The article is addressed to chemists of all branches of this discipline.

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Asenjo, Felipe A., Jens Zamanian, Mattias Marklund, Gert Brodin, and Petter Johansson. "Semi-relativistic effects in spin-1/2 quantum plasmas." New Journal of Physics 14, no. 7 (2012): 073042. http://dx.doi.org/10.1088/1367-2630/14/7/073042.

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Mota, H. F., K. Bakke, and H. Belich. "Relativistic quantum scattering yielded by Lorentz symmetry breaking effects." International Journal of Modern Physics A 32, no. 23n24 (2017): 1750140. http://dx.doi.org/10.1142/s0217751x17501408.

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We investigate the scattering of a relativistic scalar quantum particle induced by a scattering-like potential that arises from the effects of the violation of the Lorentz symmetry. We then obtain the scattering phase shift caused by the influence of such a potential and use it to calculate the exact expressions for the scattering amplitude as well as for the total scattering cross-section through the optical theorem. In addition, we estimate an upper bound for the Lorentz symmetry violation parameters.

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Kurzyński, Paweł. "Relativistic effects in quantum walks: Klein's paradox and zitterbewegung." Physics Letters A 372, no. 40 (2008): 6125–29. http://dx.doi.org/10.1016/j.physleta.2008.08.017.

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Zülicke, U., R. Winkler, and J. Bolte. "Nanospintronics meets relativistic quantum physics: Ubiquity of Zitterbewegung effects." Physica E: Low-dimensional Systems and Nanostructures 40, no. 5 (2008): 1434–35. http://dx.doi.org/10.1016/j.physe.2007.09.035.

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Kuroiwa, Josuke, Masumi Kasai, and Futamase Toshifumi. "A treatment of general relativistic effects in quantum interference." Physics Letters A 182, no. 4-6 (1993): 330–34. http://dx.doi.org/10.1016/0375-9601(93)90403-m.

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Yamamoto, Kunio. "Perturbation Expansion: Is it Asymptotic?" Modern Physics Letters A 12, no. 32 (1997): 2399–406. http://dx.doi.org/10.1142/s0217732397002491.

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It is pointed out that, for any model with bound state, contrary to the case of nonrelativistic quantum mechanics, perturbation expansion based on Feynman rules in relativistic quantum field theory is not asymptotic of physical amplitude in which the effects of bound state are considered.

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Peres, Asher, and Daniel R. Terno. "Quantum Information and Special Relativity." International Journal of Quantum Information 01, no. 02 (2003): 225–35. http://dx.doi.org/10.1142/s0219749903000127.

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Relativistic effects affect nearly all notions of quantum information theory. The vacuum behaves as a noisy channel, even if the detectors are perfect. The standard definition of a reduced density matrix fails for photon polarization because the transversality condition behaves like a superselection rule. We can however define an effective reduced density matrix which corresponds to a restricted class of positive operator-valued measures. There are no pure photon qubits, and no exactly orthogonal qubit states. Reduced density matrices for the spin of massive particles are well-defined, but are not covariant under Lorentz transformations. The spin entropy is not a relativistic scalar and has no invariant meaning. The distinguishability of quantum signals and their entanglement depends on the relative motion of observers.

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Dorokhov, A. E., A. E. Radzhabov, and A. S. Zhevlakov. "Past, present and future of the muon g-2." International Journal of Modern Physics: Conference Series 39 (January 2015): 1560107. http://dx.doi.org/10.1142/s2010194515601076.

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The electron and muon anomalous magnetic moments (AMM) are measured in experiments and studied in the Standard Model (SM) with the highest precision accessible in particle physics. The comparison of the measured quantity with the SM prediction for the electron AMM provides the best determination of the fine structure constant. The muon AMM is more sensitive to the appearance of New Physics effects and, at present, there appears to be a three- to four-standard deviation between the SM and experiment. The lepton AMMs are pure relativistic quantum correction effects and therefore test the foundations of relativistic quantum field theory in general, and of quantum electrodynamics (QED) and SM in particular, with highest sensitivity. Special attention is paid to the studies of the hadronic contributions to the muon AMM which constitute the main source of theoretical uncertainties of the SM.

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Journal articles on the topic 'Quantum and relativistic effects'

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