Journal articles: 'Imaginary density'

1

May, Robert M. "Detecting density dependence in imaginary worlds." Nature 338, no. 6210 (1989): 16–17. http://dx.doi.org/10.1038/338016a0.

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Bornyakov, V. G., D. L. Boyda, V. A. Goy, et al. "Lattice QCD at finite baryon density using analytic continuation." EPJ Web of Conferences 182 (2018): 02017. http://dx.doi.org/10.1051/epjconf/201818202017.

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We simulate lattice QCD with two flavors of Wilson fermions at imaginary baryon chemical potential. Results for the baryon number density computed in the confining and deconfining phases at imaginary baryon chemical potential are used to determine the baryon number density and higher cumulants at the real chemical potential via analytical continuation.

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Motta, M., D. E. Galli, S. Moroni, and E. Vitali. "Imaginary time density-density correlations for two-dimensional electron gases at high density." Journal of Chemical Physics 143, no. 16 (2015): 164108. http://dx.doi.org/10.1063/1.4934666.

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LOMBARDO, M. P. "Lattice QCD at Finite Temperature and Density." Modern Physics Letters A 22, no. 07n10 (2007): 457–71. http://dx.doi.org/10.1142/s0217732307023055.

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A general introduction into the subject aimed at a general theoretical physics audience. We introduce the sign problem posed by finite density lattice QCD, and we discuss the main methods proposed to circumvent it, with emphasis on the imaginary chemical potential approach. The interrelation between Taylor expansion and analytic continuation from imaginary chemical potential is discussed in detail. The main applications to the calculation of the critical line, and to the thermodynamics of the hot and normal phase are reviewed.

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Zhi Chin, Tze, A. Saidatul, and Z. Ibrahim. "Exploring EEG based Authentication for Imaginary and Non-imaginary tasks using Power Spectral Density Method." IOP Conference Series: Materials Science and Engineering 557 (June 28, 2019): 012031. http://dx.doi.org/10.1088/1757-899x/557/1/012031.

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Andres, M. V., J. M. Quesada, M. Lozano, and G. Madurga. "A level-density-dependent imaginary potential for heavy ions." Nuclear Physics A 443, no. 2 (1985): 380–96. http://dx.doi.org/10.1016/0375-9474(85)90269-6.

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Gattringer, Christof, Michael Mandl, and Pascal Törek. "New Canonical and Grand Canonical Density of States Techniques for Finite Density Lattice QCD." Particles 3, no. 1 (2020): 87–98. http://dx.doi.org/10.3390/particles3010008.

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We discuss two new density of states approaches for finite density lattice QCD (Quantum Chromo Dynamics). The paper extends a recent presentation of the new techniques based on Wilson fermions, while here, we now discuss and test the case of finite density QCD with staggered fermions. The first of our two approaches is based on the canonical formulation where observables at a fixed net quark number N are obtained as Fourier moments of the vacuum expectation values at imaginary chemical potential θ . We treat the latter as densities that can be computed with the recently developed functional fit approach. The second method is based on a direct grand canonical evaluation after rewriting the QCD partition sum in terms of a suitable pseudo-fermion representation. In this form, the imaginary part of the pseudo-fermion action can be identified and the corresponding density may again be computed with the functional fit approach. We develop the details of the two approaches and discuss some exploratory first tests for the case of free fermions where reference results for assessing the new techniques may be obtained from Fourier transformation.

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Kravchenko, S. M., V. I. Kuprikov, and A. P. Soznik. "Semimicroscopic Optical Potential with Effective Density-Dependent Nucleon-Nucleon Interaction." International Journal of Modern Physics E 07, no. 04 (1998): 465–83. http://dx.doi.org/10.1142/s0218301398000245.

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An expression for the optical potential is obtained in the nuclear matter approximation while taking into account the rearrangement potential for the generalized two-particle density-dependent Skyrme forces. The rearrangement potential influence on the nucleon-nucleus scattering is investigated. It is shown that two- and three-particle Skyrme forces are not equivalent in calculating the imaginary part of the optical potential. The intensity of the optical potential (both its real and imaginary parts) appears to be decreased considerably when the rearrangement potential is taken into account. As a result the dependence of scattering phase shifts on the incident nucleons energy is changed markedly.

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KONDO, KEI-ICHI, and KAZUHIRO YOSHIDA. "FINITE-TEMPERATURE AND FINITE-DENSITY QED: THE SCHWINGER-DYSON EQUATION IN THE REAL-TIME FORMALISM." International Journal of Modern Physics A 10, no. 02 (1995): 199–232. http://dx.doi.org/10.1142/s0217751x95000103.

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We derive, based on the real-time formalism (especially thermo-field-dynamics), the Schwinger-Dyson gap equation for the fermion propagator in QED and the four-fermion model at finite temperature and density. We discuss some advantages of the real-time formalism in solving the self-consistent gap equation, in comparison with the ordinary imaginary-time formalism. Once we specify the vertex function, we can write down the SD equation with only continuous variables without performing the discrete sum over Matsubara frequencies which cannot be performed in advance without further approximation in the imaginary-time formalism. By solving the SD equation obtained in this way, we find the chiral-symmetry-restoring transition at finite temperature and present the associated phase diagram of strong-coupling QED. In solving the SD equation, we consider two approximations: instantaneous-exchange and p0-independent ones. The former has a direct correspondence in the imaginary-time formalism; the latter is a new approximation beyond the former, since it is able to incorporate new thermal effects which have been overlooked in the ordinary imaginary-time solution. However, the two approximations are shown to give qualitatively the same results on the finite-temperature phase transition.

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10

Kashiwa, Kouji. "Imaginary Chemical Potential, NJL-Type Model and Confinement–Deconfinement Transition." Symmetry 11, no. 4 (2019): 562. http://dx.doi.org/10.3390/sym11040562.

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In this review, we present of an overview of several interesting properties of QCD at finite imaginary chemical potential and those applications to exploring the QCD phase diagram. The most important properties of QCD at a finite imaginary chemical potential are the Roberge–Weiss periodicity and the transition. We summarize how these properties play a crucial role in understanding QCD properties at finite temperature and density. This review covers several topics in the investigation of the QCD phase diagram based on the imaginary chemical potential.

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11

Almjar, Suad A., Eman O. Mafaa, Suad M. Abuzariba, and Issra M. Bunhmada. "The Effect of Rabi Frequency on the Electric Susceptibility of the Six-levels Inverted-Y Atomic Systems." International Science and Technology Journal 35, no. 1 (2024): 1–13. http://dx.doi.org/10.62341/ssei2035.

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The effect of changing the value of Rabi frequency has been studied in six level atomic system, Optical Bloch equations where used as the main tool to get the final shape of the model to treat the model. In this work we present a theoretical study of the non-linear optical properties of materials as a result of their interaction with laser radiation in resonance state. Density matrix was used in our formulation of Optical Bloch Equation. These equations were solved using Matlap program for Six-levels Inverted-Y Atomic Systems. A formula for calculation of electrical susceptibility was obtained. With increasing the real and imaginary parts of the electric susceptibility have also increased gradually which effects the index of refraction of the medium (real part), and the absorption window (described by the imaginary part). Moreover, when increasing the real and imaginary parts of the electric susceptibility decreased and we noticed that with increasing the value of the signal laser field related to transition |2⟩ ↔ |6⟩a distortion starts to appear on both real and imaginary parts. Key Words: Rabi frequency, Density matrix, electrical susceptibility, laser, Optical Bloch equations.

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12

McFarland, John, and Efstratios Manousakis. "Imaginary-time time-dependent density functional theory for periodic systems." Journal of Physics: Condensed Matter 33, no. 5 (2020): 055903. http://dx.doi.org/10.1088/1361-648x/abbe7e.

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Jung, Hwanyup. "Density of class groups of imaginary ℓ-cyclic function fields". Finite Fields and Their Applications 17, № 3 (2011): 286–93. http://dx.doi.org/10.1016/j.ffa.2010.12.005.

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14

Li, Hui, Meng He, and Ze Zhang. "Evaluating the electron density model by applying an imaginary modification." Powder Diffraction 33, no. 1 (2017): 4–10. http://dx.doi.org/10.1017/s0885715617001154.

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A function has been proposed to evaluate the electron density model constructed by inverse Fourier transform using the observed structure amplitudes and trial phase set. The strategy of this function is applying an imaginary electron density modification to the model, and then measuring how well the calculated structure amplitudes of the modified model matches the expected structure amplitudes for the modified correct model. Since the correct model is not available in advance, a method has been developed to estimate the structure amplitudes of the modified correct model. With the estimated structure amplitudes of the modified correct model, the evaluation function can be calculated approximately. Limited tests on simulated diffraction data indicate that this evaluation function may be valid at the data resolution better than 2.5 Å.

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15

G.N. Mammadova. "Optical Properties of Tlinse2<Au> Single Crystals." Journal of Electrical Systems 20, no. 7s (2024): 2237–43. http://dx.doi.org/10.52783/jes.3959.

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This paper presents the results of studying the surface microrelief in 2D and 3D models and analyzing the spectroscopy of a three-junction TlInSe2<Au> crystal. Analysis of the results obtained showed that with a change in the composition of the TlInSe2<Au> crystal, sharp changes occur in the microrelief of its surface. An X-ray optical diffraction analysis of the TlInSe2<Au> crystal was experimentally carried out. Based on ellipsometric data, optical functions were determined - the real and imaginary parts of the dielectric permittivity of crystals, the coefficients of optical absorption and reflection, the dependence of energy losses and electric field power on the effective density, the spectral dependences of the real (σr) and imaginary (σi) parts, optical electrical conductivity were experimentally studied. The fluorescence spectra of the ternary compound TlInSe2<Au> were isolated and analyzed when excited by light with a wavelength of 532 nm. X-ray studies of TlInSe2<Au> showed that this phase crystallizes into tetragonal systems. Ellipsometric measurements showed that the real (ε1) and imaginary (ε2) parts of the dielectric constant are components of the dielectric constant tensor of the uniaxial joints under consideration and do not depend on the angle. Analysis of the dependence of the real and imaginary parts of the refractive index of the TlInSe2<Au> crystal on photon energy showed that the nature of the change in the real and imaginary parts of the dielectric constant does not differ significantly. When analyzing the spectral dependences of the real (σr) and imaginary (σi) parts of the optical electrical conductivity, it was noticed that the real part of the optical electrical conductivity increases exponentially in the energy range 0.894-3.505 eV. In the energy range of 0.654-2.91 eV, the imaginary part of the optical electrical conductivity increases linearly, reaches a maximum value, and decreases at an energy of 2.91 eV. At 3.6 eV, an inversion of the imaginary part of the optical electrical conductivity of the TlInSe2<Au> compound is observed. From the graphs of the effective power density versus electric field energy losses, it is known that the effective power density increases significantly in the energy range of 0.805–3.52 eV. The fluorescence spectrum of the ternary compound TlInSe2<Au> upon excitation with light with a wavelength of 532 nm has been studied and it has been established that this phase has luminescent properties.

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DRABLIA, S., H. MERADJI, S. GHEMID, N. BOUKHRIS, B. BOUHAFS, and G. NOUET. "ELECTRONIC AND OPTICAL PROPERTIES OF BaO, BaS, BaSe, BaTe AND BaPo COMPOUNDS UNDER HYDROSTATIC PRESSURE." Modern Physics Letters B 23, no. 26 (2009): 3065–79. http://dx.doi.org/10.1142/s0217984909021235.

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We have performed first-principle full-potential (linear) augmented plane wave plus local orbital calculations (FP-L/APW + l0) with density functional theory (DFT) in local density approximation (LDA) and generalized gradient approximation (GGA), with the aim to determine and predict the electronic and optical properties of rocksalt BaO , BaS , BaSe , BaTe and BaPo compounds. First we present the main features of the electronic properties of these compounds, where the electronic band structure shows that the fundamental energy gap is indirect (Γ–X) for all compounds except for BaO which is direct (X–X). The different interband transitions have been determined from the imaginary part of the dielectric function. The real and imaginary parts of the dielectric function and the reflectivity are calculated. We have presented the assignment of the different optical transitions existing in these compounds from the imaginary part of the dielectric function spectra with respect to their correspondence in the electronic band. We have also calculated the pressure and volume dependence of the optical properties for these compounds.

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17

Landsman, N. P., and Ch G. van Weert. "Real- and imaginary-time field theory at finite temperature and density." Physics Reports 145, no. 3-4 (1987): 141–249. http://dx.doi.org/10.1016/0370-1573(87)90121-9.

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18

Yakubovsky, E. G. "INCREASED LIFE EXPECTANCY BASED ON PHYSICAL FORMULAS." Globus 7, no. 1(58) (2021): 4–6. http://dx.doi.org/10.52013/2658-5197-58-1-1.

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Life expectancy is due to the frequency of processes occurring in the body. The lower the frequency, the longer the lifespan. The frequency is influenced by the fraction of vacuum particles in a free, unbound state. Elementary particles are connected, grouped particles of vacuum. But in a free state, a large proportion of them affect the frequency of oscillations, increasing it, therefore, reducing the lifetime. The connection between a living organism and an inanimate body has been drawn. Dislocations are analogous to vacuum particles. Their low density and low fraction of vacuum particles describe the theoretical ultimate strength and lifetime. The increase in density and the formation of crystalline elementary particles cause the average lifetime and average strength, orders of magnitude smaller than the theoretical one. A further increase in the dislocation density causes cracks and ruptures, and partly chaotic formation — tumors, partly crystalline. Chaos and order are described by a complex unified field that causes tumors. This unified field is described by the hydrodynamic, acoustic, complex Reynolds number with a small imaginary part. But the formation of a small imaginary Reynolds number is an inevitable process with increasing time, as is the formation of tumors. But how to deal with them. It is necessary for the tumors to pass from a partially chaotic state to a crystalline one, forming elementary particles. This requires a periodic unified field with a wavelength equal to a constant period, which is formed by vacuum particles in elementary, crystalline particles. In addition, an imaginary magnetic field is required, which has a sign opposite to the Reynolds number. Just irradiating the tumor will not help, you need a certain wavelength and a certain sign of the imaginary magnetic

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Ulucay, T., and M. Aygun. "A comprehensive description of elastic scattering angular distributions for eight different density distribution of 32S nucleus." Revista Mexicana de Física 66, no. 3 May-Jun (2020): 336. http://dx.doi.org/10.31349/revmexfis.66.336.

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The elastic scattering angular distributions of 32S projectile by 12C, 27Al, 40Ca, 48Ca, 48Ti, 58Ni, 63Cu, 64Ni, 76Ge, 96Mo and 100Mo targets over the energy range 83.3 - 180 MeV are analyzed in the framework of the double folding model based on the optical model. The real part of the optical model potential is obtained by using double folding model for eight different density distributions of 32S which consist of Ngo, SP, 2pF, G1, G2, S, 3pF, and HFB. The imaginary part of the optical model potential is accepted as the Woods-Saxon (WS) potential. The theoretical results successfully reproduce the experimental data over both a wide energy and a wide target nucleus. Finally, simple and useful formulas which predict imaginary potential depths of each density are derived based on the elastic scattering results.

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20

Amo Usanos, Carlos, Luciano Boquete, Luis de Santiago, Rafael Barea Navarro, and Carlo Cavaliere. "Induced Gamma-Band Activity during Actual and Imaginary Movements: EEG Analysis." Sensors 20, no. 6 (2020): 1545. http://dx.doi.org/10.3390/s20061545.

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The purpose of this paper is to record and analyze induced gamma-band activity (GBA) (30–60 Hz) in cerebral motor areas during imaginary movement and to compare it quantitatively with activity recorded in the same areas during actual movement using a simplified electroencephalogram (EEG). Brain activity (basal activity, imaginary motor task and actual motor task) is obtained from 12 healthy volunteer subjects using an EEG (Cz channel). GBA is analyzed using the mean power spectral density (PSD) value. Event-related synchronization (ERS) is calculated from the PSD values of the basal GBA (GBAb), the GBA of the imaginary movement (GBAim) and the GBA of the actual movement (GBAac). The mean GBAim and GBAac values for the right and left hands are significantly higher than the GBAb value (p = 0.007). No significant difference is detected between mean GBA values during the imaginary and actual movement (p = 0.242). The mean ERS values for the imaginary movement (ERSimM (%) = 23.52) and for the actual movement (ERSacM = 27.47) do not present any significant difference (p = 0.117). We demonstrated that ERS could provide a useful way of indirectly checking the function of neuronal motor circuits activated by voluntary movement, both imaginary and actual. These results, as a proof of concept, could be applied to physiology studies, brain–computer interfaces, and diagnosis of cognitive or motor pathologies.

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Nakano, Masayoshi, Harunori Fujita, Masahiro Takahata та Kizashi Yamaguchi. "Density analysis of imaginary part of γ related to two-photon absorption". Chemical Physics Letters 356, № 5-6 (2002): 462–68. http://dx.doi.org/10.1016/s0009-2614(02)00353-6.

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Guo, Ye, Xin Huang, and Bao Lin Zhu. "A Calculation Method for Packing Density of Powder in Paste with Continuous Grain Size Distribution." Key Engineering Materials 477 (April 2011): 125–31. http://dx.doi.org/10.4028/www.scientific.net/kem.477.125.

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By regarding the powder particles warpped with water film as compounded particles, the packing density of powder particles in actual paste system is transformed into the packing density of compounded partcles in imaginary dry-particle system. Based on Stovall Model, a calculation method for packing density of powder with continuous particle size distribution in paste is developed, and the parameters in the method are dentified by experiment. This calculation method could be used to simulate the packing density of cementitious materials such as cement, fine slag, and fly ashes.

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23

Szymański, Michał. "Deconfinement of heavy quarks at finite density and strong magnetic field." European Physical Journal Special Topics 229, no. 22-23 (2020): 3387–94. http://dx.doi.org/10.1140/epjst/e2020-000115-3.

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AbstractWe study the simultaneous effect of the external magnetic field and finite chemical potential on deconfinement of heavy quarks, probed by the Polyakov loop and its fluctuations. We calculate the Polyakov loop, its real and imaginary susceptibilities, their ratio, as well as the heavy quark and anti-quark entropies. We find that these quantities are sensitive probes of deconfinement. Especially, the real Polyakov loop susceptibility and heavy quark and anti-quark entropies diverge at the critical point.

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Zhao, Xuean, and Zheng-Quan Pan. "Low Frequency AC Nonlinear Dynamic Admittance in Quantum Dot Structure." International Journal of Modern Physics B 17, no. 22n24 (2003): 4402–6. http://dx.doi.org/10.1142/s0217979203022520.

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In the framework of scattering theory and in terms of the notion of local partial density of states(LPDOS), we derived the expressions of the linear and the second order nonlinear emittance, which is the imaginary part of admittance, for the quantum dot structure. With the help of discrete Hamiltonian model we obtained the linear and the second nonlinear partial density of states. By using the linear and the nonlinear emittance we could obtain expressions which can be used to detect the density of state(DOS) of the sample.

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JAHANGIRLI, Z. A., I. R. AMIRASLANOV, A. B. RAHIMLI, R. G. SEIDOV, and T. O. BAYRAMOVA. "AB INITIO AND EXPERIMENTAL STUDY OF ELECTRONIC AND OPTICAL PROPERTIES OF GAINS3." Izvestiya vysshikh uchebnykh zavedenii. Fizika 67, no. 6 (2024): 57–62. https://doi.org/10.17223/00213411/67/6/9.

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The electronic and optical properties of GaInS3 were studied experimentally by spectral ellipsometry, as well as theoretically using Density Functional Theory (DFT). The real and imaginary parts of the dielectric function were determined in the energy range 0.7-6.5 eV. From the calculated electronic spectrum and density of energy states, the band gap was estimated. Based on the analysis of partial densities of electronic states projected onto atoms (PDOS), the nature of the chemical bond in GaInS3 was determined.

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Jung, Hwanyup. "DENSITY OF IMAGINARY CUBIC FUNCTION FIELDS HAVING INFINITE HILBERT 3-CLASS FIELD TOWER." Honam Mathematical Journal 34, no. 4 (2012): 597–601. http://dx.doi.org/10.5831/hmj.2012.34.4.597.

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27

Davgiikhorol, Naranchimeg, Munkhsaikhan Gonchigsuren, Khenmedekh Lochin, Sukh Ochir, and Tsogbadrakh Namsrai. "Imaginary Time Density Functional Calculation of Ground States of Atoms Using CWDVR Approach." Journal of Modern Physics 10, no. 09 (2019): 1134–43. http://dx.doi.org/10.4236/jmp.2019.109073.

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Wang, Ting, Jie Zhou null, and Guanghui Hu. "An SAV Method for Imaginary Time Gradient Flow Model in Density Functional Theory." Advances in Applied Mathematics and Mechanics 15, no. 3 (2023): 719–36. http://dx.doi.org/10.4208/aamm.oa-2021-0363.

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Arya, Aditya Kumar, Varsha Yadav, et al. "An Ab Initio Analysis of Structural, optical, Electronic, and Thermal Properties of Cubic SrSnO3 using Wein2k." East European Journal of Physics, no. 4 (December 6, 2022): 164–70. http://dx.doi.org/10.26565/2312-4334-2022-4-16.

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This paper investigated the structural, optical, electronic and thermal characteristics of SrSnO3 perovskites that were calculated using the density functional theory. Software called WEIN2K is used to perform the calculation. According to our calculations, the band gap energy of the SrSnO3 is roughly 4.00 eV and it adopts a distorted cubic shape in the space group Pm3-m. The band structure and partial density of state reflects the major contribution of O 2p in the valence band while 5s orbital from Sn in the conduction band. The electron density plot significantly shows the contribution different clusters SrO12 and SnO6 that plays crucial role in electronic and optical properties. The creation of covalent bonds between the atoms of Sn and O as well as the ionic interaction between the atoms of Sr and O are both demonstrated by the electron density graphs and SCF calculation. The refractive index and extinction coefficient directly correlated with the real and imaginary part of complex dielectric function. Real part of dielectric function shows higher values at two major point of energy 3.54 eV and 9.78 eV associated with the absorption and optical activity of SrSnO3. Negative part of imaginary dielectric function part suggests metallic behavior also supported by -grep lapw method. Thermoelectric and thermal conductivity properties suggest the power factor need to be improved for the device application.

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BERG, PETER, and GREGORY KOZLOWSKI. "NUMERICAL CALCULATIONS OF IMAGINARY SUSCEPTIBILITY IN THE INTERGRAIN REGION OF GRANULAR SUPERCONDUCTORS." Modern Physics Letters B 03, no. 15 (1989): 1163–70. http://dx.doi.org/10.1142/s0217984989001783.

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Using a critical state model for the intergrain critical current density (J c ) of a granular superconductor in which the grains are separated by Josephson junction type weak links, numerical calculations of the imaginary part of the complex susceptibility (χ″) and the ac losses (W) are performed. The dependences of the imaginary susceptibility on the amplitude of the external magnetic field (Hac), grain size (R g ), barrier width (d), lower critical field (H cl ), normal resistivity of the junction (ρj) and temperature (T) are discussed. We also comment on a minimum in the hysteretic ac losses when a constant magnetic field (Hdc) is superimposed on the alternating field. Some comparison with experimental data is made.

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Zhang, Huai-Yong, Zhao-Yi Zeng, Ying-Qin Zhao, Qing Lu, and Yan Cheng. "First-Principles Study of Lattice Dynamics, Structural Phase Transition, and Thermodynamic Properties of Barium Titanate." Zeitschrift für Naturforschung A 71, no. 8 (2016): 759–68. http://dx.doi.org/10.1515/zna-2016-0149.

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AbstractLattice dynamics, structural phase transition, and the thermodynamic properties of barium titanate (BaTiO3) are investigated by using first-principles calculations within the density functional theory (DFT). It is found that the GGA-WC exchange-correlation functional can produce better results. The imaginary frequencies that indicate structural instability are observed for the cubic, tetragonal, and orthorhombic phases of BaTiO3 and no imaginary frequencies emerge in the rhombohedral phase. By examining the partial phonon density of states (PDOSs), we find that the main contribution to the imaginary frequencies is the distortions of the perovskite cage (Ti-O). On the basis of the site-symmetry consideration and group theory, we give the comparative phonon symmetry analysis in four phases, which is useful to analyze the role of different atomic displacements in the vibrational modes of different symmetry. The calculated optical phonon frequencies at Γ point for the four phases are in good agreement with other theoretical and experimental data. The pressure-induced phase transition of BaTiO3 among four phases and the thermodynamic properties of BaTiO3 in rhombohedral phase have been investigated within the quasi-harmonic approximation (QHA). The sequence of the pressure-induced phase transition is rhombohedral→orthorhombic→tetragonal→cubic, and the corresponding transition pressure is 5.17, 5.92, 6.65 GPa, respectively. At zero pressure, the thermal expansion coefficient αV, heat capacity CV, Grüneisen parameter γ, and bulk modulus B of the rhombohedral phase BaTiO3 are estimated from 0 K to 200 K.

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Narimani, M., and Z. Nourbakhsh. "Topological band order, structural, electronic and optical properties of XPdBi (X = Lu, Sc) compounds." Modern Physics Letters B 30, no. 14 (2016): 1650159. http://dx.doi.org/10.1142/s0217984916501591.

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In this paper, the structural, electronic and optical properties of LuPdBi and ScPdBi compounds are investigated using the density functional theory by WIEN2K package within the generalized gradient approximation, local density approximation, Engel–Vosco generalized gradient approximations and modified Becke–Johnson potential approaches. The topological phases and band orders of these compounds are studied. The effect of pressure on band inversion strength, electron density of states and the linear coefficient of the electronic specific heat of these compounds is investigated. Furthermore, the effect of pressure on real and imaginary parts of dielectric function, absorption and reflectivity coefficients of these compounds is studied.

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Najat A. Dahham, Abdul-Samee Fawzi Abdul-Aziz, and Atyaf Sabah Khalaf Jasim. "Fabrication And Studies Of structural, Dielectrical Properties Of (Ni0.95-xCoxCu0.05Fe2O4) Composites by Powder Technology Method." Tikrit Journal of Pure Science 22, no. 11 (2023): 48–54. http://dx.doi.org/10.25130/tjps.v22i11.913.

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In this paper, the preparation of compounds, Ni0.95CoxCu0.05Fe2O4) by using powder technology method where (X = 0, 0.01, 0.02, 0.03, 0.04,and 0.05) annealing at 1100 C temperature for four hours. A series of samples were carried out for the study of structural properties by measuring x-ray diffraction (XRD). It included the study of the lattice constant (a), the particle size (D), the porosity (P) and the virtual density by x-ray diffraction, (x-ray density) as well as the study of Dielectric properties using the LCR , the study of the loss of dielectric meter tand and the electric conductivity (Ϭac). The results of X-ray diffraction showed that all samples had a crystalline,) and also showed that the Lattice constant (a) increases as the content of cobalt increases the density of the particles calculated by X-ray diffraction increases with the cobalt content, while the porosity and particles size decreases as the cobalt content increases, and the electrical show that the real and imaginary dielectric and electrical conductivity using current decreases as frequency increases, the real electrical dielectric constant increases as the cobalt content increases, while the imaginary part of dielectric constant and electrical conductivity decreases as the cobalt content increases.

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GÓMEZ NICOLA, A., and R. F. ALVAREZ-ESTRADA. "ANOMALIES AT FINITE TEMPERATURE AND DENSITY." International Journal of Modern Physics A 09, no. 09 (1994): 1423–42. http://dx.doi.org/10.1142/s0217751x94000637.

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Chiral anomalies for Abelian and non-Abelian quantum field theories at finite temperature and density (FTFD) are analyzed in detail in both imaginary and real time (IT and RT) formalisms. IT and RT triangle diagrams and IT functional methods (à la Fujikawa) are used at FTFD. The vector anomaly (the one regarding the lepton and baryon numbers) in the Weinberg–Salam theory, for an arbitrary number of fermion families, is also treated using IT functional methods at FTFD. In all cases, the expressions for the FTFD anomalies (as functions of the corresponding quantities) turn out to be identical to those at zero temperature and density, thereby extending previous results by various authors for the finite temperature and zero density case. Moreover, the independence of anomalies from temperature and density is shown to be consistent, at least in the Abelian case, with the analytic continuation from the IT formulation to the RT one.

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Cai, Xue Mei, and Yuan Luo. "Electronic and Optical Properties of the Zn and Mg Doped AlN." Materials Science Forum 663-665 (November 2010): 195–98. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.195.

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The electronic and optical properties of hexagonal wurtzite AlN doped with Zn and Mg are studied based on the density functional theory. The density of states, dielectric function and absorption spectra are calculated using plane-wave ultrasoft pseudo-potential and the generalized gradient approximation (GGA). The absorption peaks are found during 0-13 eV and 43-48 eV in Mg doped AlN, while in Zn doped AlN, only during 0-15eV. The absorption peak about 43-48 eV found in Mg doped AlN is due to the transition of the deep 2p energy level in Mg to conduction band. The first peak of the dielectric imaginary part is related to the transition of the doped atoms. The peak of the dielectric imaginary part and absorption peak appears about 8 eV is due to the transition of N 2p to Al 3p state. Results show that the electronic and the optical properties of hexagonal wurtzite AlN are directly related to the electronic structure of the impurities in the crystal.

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Doi, Takahiro M., and Kouji Kashiwa. "Dirac-mode analysis for quark number density and its application for deconfinement transition." EPJ Web of Conferences 175 (2018): 12003. http://dx.doi.org/10.1051/epjconf/201817512003.

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The quark number density at finite imaginary chemical potential is investigated in the lattice QCD using the Dirac-mode expansion. We find the analytical formula of the quark number density in terms of the Polyakov loop in the large quark mass regime. On the other hand, in the small quark mass region, the quark number density is investigated by using the quenched lattice QCD simulation. The quark number density is found to strongly depend on the low-lying Dirac modes while its sign does not change. This result leads to that the quark number holonomy is not sensitive to the low-lying Dirac modes. We discuss the confinement-deconfinement transition from the property of the quark number density and the quark number holonomy.

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Nuralieva, N. F., A. A. Lavrenyuk, M. Zh Adjiasanova, et al. "Syndrome of imaginary excess of mineralocorticoids: a clinical case." FOCUS. Endocrinology 5, no. 1 (2024): 74–80. http://dx.doi.org/10.62751/2713-0177-2024-5-1-10.

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The syndrome of apparent mineralocorticoid excess (AME) is a rare genetic disease characterized by juvenile hypertension, hypokalemia, suppression of renin and aldosterone. AME syndrome is caused by a mutation in the HSD11B2 gene, which encodes 11ß-hydroxysteroid dehydrogenase type 2, that converts cortisol into cortisone.The purpose of the article is to describe a clinical case of genetically confirmed (mutation C.911A>G of the HSD11B2 gene) AME syndrome. The disease manifested in the first years of life; the patient was prescribed mineralocorticoid receptor antagonists, potassium preparations, potassium-sparing diuretics, and other antihypertensive therapy. Due to the absence of normotonia and normokalemia, dexamethasone has been prescribed since the age of 12. Due to uncontrolled arterial hypertension and hypokalemia, complications developed (medullary nephrocalcinosis, myocardial remodeling), and prolonged dexamethasone intake led to a slowdown in puberty and a decrease in bone mineral density.

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38

Emerson, D. W., and H. K. Welsh. "Low‐frequency permittivities of skarns and associated rocks." GEOPHYSICS 53, no. 9 (1988): 1233–40. http://dx.doi.org/10.1190/1.1442564.

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The lossy dielectric properties of dry heterogeneous skarns and associated rocks vary significantly when the real (ε′) and quadrature (ε″) permittivity responses are measured between 1 Hz and 160 kHz. Ores containing iron oxides and/or sulfides show very large permittivity values and high loss tangents with some dc conductivity. Unmineralized skarns manifest large ε′ and moderate ε″ values. Country rock, limestones, and granitoids show relatively low permittivities. The dielectric responses are ascribed generally to Maxwell‐Wagner mechanisms. No clear, convincing correlations are apparent between petrological characteristics and dielectric properties, but as iron and titanium content increases, so does the imaginary permittivity. Both real and imaginary permittivities are strongly influenced by density, and this effect must be removed before the effects of mineralogy can be observed.

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SBÂRCIOG, C., R. T. REDAC, I. GR. DEAC, and I. POP. "INTERGRANULAR PROPERTIES OF Zr-SUBSTITUTED Y123 COMPOUNDS." Modern Physics Letters B 20, no. 19 (2006): 1191–98. http://dx.doi.org/10.1142/s0217984906011554.

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AC susceptibility measurements have been done to determine the intergranular properties for some 123-superconducting ceramics. From the imaginary part of the complex susceptibility, χ″(T), the temperature dependence of the critical current density was determined by using Bean's model. The intergranular current density was experimentally determined from AC susceptibility data by varying the field amplitude. All intragrain critical parameters are gradually degraded with increasing the concentration of the dopant substituting on the rare-earth side and with decreasing the sintering temperature during the sample preparation.

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Gerasimeniuk, Nikolai, Vitaly Bornyakov, Vladimir Goy, et al. "Lee–Yang Zeroes in the Baryon Fugacity Plane: The Role of High Densities." Particles 6, no. 3 (2023): 834–46. http://dx.doi.org/10.3390/particles6030053.

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We compute the canonical partition functions and the Lee–Yang zeros in Nf=2 lattice QCD at temperature T=1.20Tc lying above the Roberge–Weiss phase transition temperature TRW. The phase transition is characterized by the discontinuities in the baryon number density at specific values of imaginary baryon chemical potential. We further develop our method to compute the canonical partition functions using the asymptotic expression for respective integral. Then, we compute the Lee–Yang zeros and study their behavior in the limit of high baryon density.

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Belonenko, Mikhail B., Natalia N. Konobeeva, Dmitry V. Smovzh, Alexander V. Zhukov, and Roland Bouffanais. "Tunneling characteristics of a contact between a superlattice and non-Fermi liquid using the AdS/CFT correspondence." Modern Physics Letters B 28, no. 21 (2014): 1450170. http://dx.doi.org/10.1142/s021798491450170x.

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In this paper, we investigate the peculiar features of the tunneling contact between a superlattice and a non-Fermi quantum liquid. The imaginary part of the Green functions are responsible for the non-Fermi liquid density of states. The Green functions have been derived within the framework of the anti-de Sitter/conformal field theory correspondence.

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42

Gilani, Zaheer Abbas, Siraj Ul Islam, H. M. Noor ul Huda Khan Asghar, Rafaqat Hussain, and Furhaj Ahmad Shaikh. "Impact of Lanthanum Doping on the Structural, Electrical, and Magnetic Properties of BaFe12O19 Nano Particles." Journal of Materials and Physical Sciences 2, no. 1 (2021): 22–32. http://dx.doi.org/10.52131/jmps.2021.0201.0013.

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These ferrites had been considered very highly valuable electronic materials for many decades. The ferrite compounds have a hexagonal structure. Nano structural and dielectric features for BaFe12-xLaxO19 (0.00, 0.25.0.50, 0.75, 1.00) nano Hexaferrite (NHFs) was studied present research. The Ba NHF prepared via sol-gel technique. The single phase of barium Nano Hexaferrites of various sample was confirmed by XRD, the average crystalline size calculated in the range of 5 to 13 nm.The lattice parameter lattice constant, X-ray density, bulk density, micro strain and lattice strain are the parameters of XRD which are also calculated. The different parameters of XRD also show the decreasing and increasing trend which is totally depend on the concentration. The hexagonal structure also confirmed by FTIR. There are two frequency band are investigated which are ?1 and ?2 which are associated with tetrahedral stretching band and octahedral stretching band respectively. The different frequency band are calculated at different frequency like ?1=500 to 540 and also ?2 = 413. The dielectric properties also measured in the frequency range from 1 MHz to 3 GHz. There are many others parameters are calculated in dielectric properties such as real and imaginary electric modulus, real and imaginary impedance, dielectric constant, dielectric loss and tangent loss. The parameters of dielectric also showing decreasing and increasing in trend. The real and imaginary impedance plot changes as when the frequency increases, the all the specimens converge on one another, and at a higher frequency, the impedance exhibits coherent nature, which is due to the discharge of space charges.

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Sutinjo, A. T., M. Kovaleva, and Y. Xu. "System Equivalent Flux Density of a Polarimetric Tripole Radio Interferometer." Publications of the Astronomical Society of the Pacific 134, no. 1031 (2022): 014502. http://dx.doi.org/10.1088/1538-3873/ac4383.

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Abstract Electromagnetic and information properties of tripole antennas have been studied since the 1980s. In radio astronomy, tripole antennas find an application in space telescopes. More recently, a radio interferometer with satellite-borne tripole antennas is being considered for a lunar orbiting radio telescope to observe very long wavelengths. System equivalent flux density (SEFD) is an important figure of merit of a radio telescope. This paper aims to derive a general expression for SEFD of a polarimetric tripole interferometer. The derivation makes only two basic and reasonable assumptions. First, the noise under consideration is zero mean and when expressed in complex phasor domain, has independent and identically distributed (iid) real and imaginary components. Correlated and non-identically distributed noise sources are allowed as long as the real and imaginary components remain iid. Second, the system noise is uncorrelated between the elements separated by a baseline distance. The SEFD expression is derived from first principles, that is the standard deviation of the noisy flux estimate in a target direction due to system noise. The resulting SEFD expression is expressed as a simple matrix operation that involves a mixture of the system temperatures of each antenna and the Jones matrix elements. It is not limited to tripoles, but rather, fully extensible to multipole antennas; it is not limited to mutually orthogonal antennas. To illustrate the usefulness of the expression and how the formula is applied, we discuss an example calculation based on a tripole interferometer on lunar orbit for ultra-long wavelengths observation. We compared the SEFD results based on a formula assuming short dipoles and the general expression. As expected, the SEFDs converge at the ultra-long wavelengths where the dipoles are well-approximated as short dipoles. The general SEFD expression can be applied to any multipole antenna systems with arbitrary shapes.

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44

Soni, K., V. Jain, and N. Lakshmi. "First-principles calculations of electronic and optical properties in the bulk and on the (001) surface of CsPbCl₃." Journal of Physics: Conference Series 2070, no. 1 (2021): 012014. http://dx.doi.org/10.1088/1742-6596/2070/1/012014.

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Abstract We perform density functional theory using first-principles calculations in order to investigate the band structure, density of states, the real and imaginary part of dielectric function, refractive index and optical absorption of CsPbCl3 in the bulk and (001) surface structure. Energy bands exhibits wide and direct bandgap. When CsPbCl3 is extended to (001) surface a decrease of band gap is observed with increasing thickness. The optical constants observed exhibits optimal properties in the ultraviolet and visible range indicating its usefulness in photonic, optoelectronic, photovoltaic and optomagnetic devices.

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Shao, Ting Ting, Fu Chun Zhang, and Wei Hu Zhang. "First Principles Studies on Structural, Electronic and Optical Properties of SnO₂." Advanced Materials Research 900 (February 2014): 203–8. http://dx.doi.org/10.4028/www.scientific.net/amr.900.203.

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The structural, electronic, and optical properties of rutile-type SnO2 are studied by plane-wave pseudopotential density functional theory (DFT) with GGA, LDA, B3LYP and PBE0 respectively. The computing results show that the band gap getting from PBE0 and B3LYP is much more consistent with the available experimental data than that from GGA and LDA, no matter what the latter use ultra-soft pseudopotential or norm conserving pseudopotential. However, the density of state, real part and imaginary part of dielectric function calculating from every type is basically similar in qualitative analysis.

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Goswami, Jishnu, D. A. Clarke, P. Dimopoulos, et al. "Exploring the critical points in QCD with multi-point Padé and machine learning techniques in (2+1)-flavor QCD." EPJ Web of Conferences 296 (2024): 06007. http://dx.doi.org/10.1051/epjconf/202429606007.

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Using simulations at multiple imaginary chemical potentials for (2 + 1)-flavor QCD, we construct multi-point Padé approximants. We determine the singularties of the Padé approximants and demonstrate that they are consistent with the expected universal scaling behaviour of the Lee-Yang edge singularities. We also use a machine learning model, Masked Autoregressive Density Estimator (MADE), to estimate the density of the Lee-Yang edge singularities at each temperature. This ML model allows us to interpolate between the temperatures. Finally, we extrapolate to the QCD critical point using an appropriate scaling ansatz.

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Wang, Xiaolu, Lin Mei, Zhenduo Wang, and Naitong Zhang. "On the probability density function of the real and imaginary parts in WFRFT signals." China Communications 13, no. 9 (2016): 44–52. http://dx.doi.org/10.1109/cc.2016.7582295.

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KHANAL, U. "FURTHER COMMENTS ON THE DYNAMICS OF EXTENDED OBJECTS." Modern Physics Letters A 13, no. 34 (1998): 2757–61. http://dx.doi.org/10.1142/s0217732398002928.

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The equation of motion of the internal coordinates of a p-brane, arising from the stationarity of the world space Einstein–Hilbert action, is discussed. Assuming the Einstein equation of general relativity, with the energy–momentum tensor of a perfect fluid having positive energy density, it is shown that the governing equation, in matter dominated regions with positive pressure is a (p+1)-dimensional elliptic differential equation which reduces to the (p+1)-dimensional Laplace equation for constant density and pressure. The EOM becomes a hyperbolic p-dimensional wave equation in conducto-dispersive medium only in regions of world space, like those dominated by vacuum, where the total pressure is negative. The Green's function of the matter dominated, elliptic potential problem presented here for p=3, can be analytically continued into the complexified time domain to make contact on the imaginary axis with the Green's function of the wave equation for vacuum domination. Such considerations will allow the study of the matter–vacuum interface using complex time, whence matter domination with positive pressure would be represented on the real axis, vacuum domination with negative pressure on the imaginary axis, and the transition represented by the complex region.

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Shanshal, Muthana, and Rehab M. Kubba. "Bonding, Electron Densities and Vibration Frequencies of [3]-, [4]-, [5]- and [6]-Radialenes; a B3LYP Density Functional Study." Zeitschrift für Naturforschung A 61, no. 1-2 (2006): 95–98. http://dx.doi.org/10.1515/zna-2006-1-216.

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B3LYP density functional treatment is reported for the [3]- to [6]-radialene. For the first two molecules the corresponding Dnh symmetry resulted from the treatment. For the [5]-radialene, the completely planar D5h structure was found energetically a non-minimal configuration showing two imaginary vibrations. An almost planar C1 structure of [5]-radialene emerged as the stable species. As for [6]-radialene, the planar D6h structure proved to be a non-minimal structure too, showing three imaginary vibrations. The D3d chair form was most stable, followed by a twisted boat form of the molecule. The chair form of [6]-radialene was more stable than the twist boat form by 0.9 kcal/mol. Variation of the bond lengths, of A1g (νCC and νCH) vibration frequencies as well as of the total (ρtot) and σ (ρσ ) electron densities for the four molecules, compared with those of ethylene, is discussed. To explain the results, a bonding model for the radialene rings is suggested, which assumes an sp hybridization of the ring atoms in [3]- and [4]-radialenes going over to sp2 hybridization in [5]- and [6]-radialenes.

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Iakovlev, Serguei I. "Description of the structure of singular spectrum for Friedrichs model operator near singular point." International Journal of Mathematics and Mathematical Sciences 28, no. 1 (2001): 25–40. http://dx.doi.org/10.1155/s0161171201011668.

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The study of the point spectrum and the singular continuous one is reduced to investigating the structure of the real roots set of an analytic function with positive imaginary partM(λ). We prove a uniqueness theorem for such a class of analytic functions. Combining this theorem with a lemma on smoothness ofM(λ)near its real roots permits us to describe the density of the singular spectrum.

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Journal articles on the topic 'Imaginary density'

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