Article
Astronomy & Astrophysics
Ankur Srivastav, Sunandan Gangopadhyay
Summary: In this study, novel vortex solutions in a rotating holographic superfluid were analytically devised, showing a correlation between vortices and quantized rotation of the superfluid. It was observed that an imaginary chemical potential leads to a decrease in the winding number of vortices in such holographic superfluids, indicating less dissipation.
Article
Astronomy & Astrophysics
Ankur Srivastav, Sunandan Gangopadhyay
Summary: We have extended our previous work on rotating holographic superfluids to include Lifshitz scaling, which breaks relativistic invariance and indicates the existence of a Lifshitz fixed point. We analytically showed that we still obtain the same vortex solutions as before. However, for z ≠ 1, our study revealed surprising results regarding dissipation in the holographic superfluid, showing that higher winding number vortices increase with higher imaginary chemical potential in the open interval (1, 2).
Article
Astronomy & Astrophysics
Jhony A. Herrera-Mendoza, Daniel F. Higuita-Borja, Julio A. Mendez-Zavaleta, Alfredo Herrera-Aguilar, Felipe Perez-Rodriguez
Summary: We constructed a type-II holographic superconductor using an anisotropic rotating background metric. We investigated the influence of the magnetic field on the vortex structure, observing continuous deformations from triangular to square lattices or vice versa. Our holographic model accurately reproduces known experimental vortex lattice deformations and the increment of vortex population with increasing external magnetic field.
Article
Physics, Particles & Fields
Ankur Srivastav, Sunandan Gangopadhyay, Ashis Saha
Summary: In this study, we analytically computed the holographic transport coefficients for (2 + 1)-dimensional strongly coupled field theories subjected to a spatially modulated chemical potential along the x-direction, considering the presence of Born-Infeld electrodynamics. The coefficients were obtained solely in terms of the black hole horizon data. It was observed that the Born-Infeld parameter has a non-trivial impact on these coefficients. These results were then used to investigate a holographic model for ultra-clean graphene near the Dirac point, which involved a two current model with an inhomogeneous holographic lattice.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Chuan-Yin Xia, Hua-Bi Zeng, Yu Tian, Chiang-Mei Chen, Jan Zaanen
Summary: The AdS/CFT correspondence provides a unique method to study vortex matter phases in superconductors. By solving the dynamical evolution of a 2+1-dimensional superconductor at finite temperature and subjected to a magnetic field quench in terms of a gravitational hairy black hole in an asymptotic AdS 4 space, we can determine the nature of equilibrium states after the quench. Our results show the existence of Meissner phase and Abrikosov lattices under different external magnetic field conditions, consistent with the expectations of Ginzburg-Landau theory.
Article
Multidisciplinary Sciences
Giacomo Mazza, Marco Gandolfi, Massimo Capone, Francesco Banfi, Claudio Giannetti
Summary: This study explores unconventional electronic heat transfer phenomena in layered strongly correlated materials, demonstrating the ability of these systems to sustain a wide spectrum of electronic heat transport regimes, ranging from ballistic to hydrodynamic to diffusive. The interaction strength can be controlled to manipulate the dynamics of temperature waves and the onset of different thermal transport regimes. Quantum correlated materials offer a promising platform for the study of unconventional heat transfer.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Particles & Fields
Weiping Yao, Qiong Yang, Xiaobao Liu, Jiliang Jing
Summary: Through studying the behavior of the HEE in holographic superconductor models, we found that the slope of the HEE exhibits discontinuous behavior at the phase transition point for different parameters, and the stronger nonlinearity of the LNE results in smaller HEE in metal/superconductor models. Additionally, the behavior of the HEE also suggests a confinement/deconfinement phase transition in the insulator/superconductor models.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Materials Science, Multidisciplinary
Z. Y. Tian, Q. Y. Zhang, Y. W. Xiao, G. A. Gamage, F. Tian, S. Yue, V. G. Hadjiev, Jiming Bao, Zhifeng Ren, Erjun Liang, Jimin Zhao
Summary: We investigated the ultrafast quasiparticle dynamics of cubic boron arsenide and identified the interactions between electrons and phonons that contribute to its high thermal conductivity. The weak electron-phonon coupling strength and the importance of preserving this weak coupling for achieving ultrahigh thermal conductivity were demonstrated. Our findings offer insights for the search and design of materials with high thermal conductivity.
Article
Physics, Multidisciplinary
Mahya Mohammadi, Ahmad Sheykhi
Summary: In this study, we investigate the effects of Gauss-Bonnet gravity on the properties of holographic s-wave and p-wave superconductors in lower-dimensional spacetime. The results reveal that increasing mass, nonlinear gauge field, and Gauss-Bonnet parameters leads to lower critical temperature and higher condensation. The behavior of electrical conductivity in different dimensions is also explored.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Materials Science, Multidisciplinary
Kouki Nakata, Yuichi Ohnuma
Summary: We present a formula for thermal transport in the bulk of Bose systems based on the quantum Boltzmann equation (QBE). By applying the formula to magnons and using a relaxation time approximation, we find that the thermal conductivity of the QBE exhibits different behavior from the conventional Boltzmann equation. The thermal conductivity of the QBE reduces to the Drude type in the limit of the quasiparticle approximation, showing enhancement beyond the conventional thermal transport property.
Article
Physics, Multidisciplinary
Qian Xiang, Li Zhao, Yong-Qiang Wang
Summary: In this paper, we generalize the study of holographic superconductors in excited states to the framework of massive gravity at the probe limit. We numerically present a family of solutions for holographic superconductors in excited states, taking into account the effect of a massive graviton. The critical temperatures of these solutions can be higher due to the effect of the massive graviton compared to superconductors in Einstein gravity. We also investigate the condensates and conductivities in the ground state and excited states by studying various parameters determining the gravity background framework.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Anita Kumari, Rakhi Sharma, Radhika Chauhan, B. D. Indu
Summary: This study analyzes the thermal conductivity of rare earth substituted high temperature superconductors and investigates the role of various scattering processes in thermal transport. The study finds that boundary scattering is the main contributor to thermal resistance at very low temperatures and explores the anisotropic nature of thermal conductivity in single-crystal YBCO.
Article
Optics
Suyeon Choi, Jonghyun Kim, Yifan Peng, Gordon Wetzstein
Summary: Michelson holography (MH) is a holographic display technology that optimizes image quality for emerging holographic near-eye displays by using two SLMs to cancel out undiffracted light. The system is calibrated using camera-in-the-loop holography techniques and demonstrates state-of-the-art 2D and multi-plane holographic image quality.
Article
Physics, Particles & Fields
Ting Zhang, Ya-Bo Wu, Cheng-Yuan Zhang
Summary: By using the numerical method, the properties of holographic paramagnetism/ferromagnetism phase transition for the Power-Maxwell field in the background of a Schwarzschild-AdS black hole are investigated. It is found that a larger power parameter q decreases the critical temperature and hinders the formation of magnetic moment. Moreover, in the presence of an external magnetic field, the magnetic susceptibility density with different q values satisfies the Curie-Weiss law, and hysteresis loops appear for different q values.
Article
Physics, Multidisciplinary
Grigoris Panotopoulos
Summary: In the framework of the gauge/gravity duality, we study one-dimensional superconductors by analyzing the dual (1+2)-dimensional gravity with Einstein-power-Maxwell non-linear Electrodynamics. We compute the critical temperature of the transition as a function of the mass of the scalar field in the probe limit and perform the computation analytically using the Rayleigh-Ritz variational principle. Comparison with higher dimensional power Maxwell field and (1+3)-dimensional Einstein-Maxwell theory for two-dimensional superconductors is also made.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
R. A. Konoplya
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: The study reveals stable circular orbits in D-dimensional asymptotically anti-de Sitter black holes, unlike the flat case, indicating the presence of stable orbits for any higher curvature Lovelock corrections, with a universal scaling relationship with temperature.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: Recent research has found an exact solution describing a black hole immersed in a galactic-like distribution of matter. This study continues the analysis of the properties of this geometry through consideration of electromagnetic radiation. The influence of the environment on classical and quantum radiation around such black holes is estimated to be relatively small.
Article
Physics, Multidisciplinary
R. A. Konoplya, A. Zhidenko
Summary: Blazquez-Salcedo et al. obtained asymptotically flat traversable wormhole solutions in the Einstein-Dirac-Maxwell theory without phantom matter. The previously found solutions had issues, whereas the new solutions are asymmetric and endowed with smooth gravitational and matter fields, making them more realistic.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: This study considers various profiles of matter distribution in galactic halos as the source term for the Einstein equations and finds exact solutions that represent the metric of a central black hole immersed in a galactic halo. Very accurate general analytical metrics, including all the particular models, are found in the astrophysically relevant regime.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: This article discusses the correspondence between quasinormal modes and parameters of circular null geodesics. The correspondence was initially proposed for gravitational and test field perturbations, but it was later found that it only holds for test fields and may be broken for gravitational and other non-minimally coupled fields. The article further specifies the correspondence and shows that even when it is guaranteed, it may not represent the full spectrum of quasinormal modes.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: During the ringdown phase, the least damped quasinormal frequency dominates the gravitational signal emitted by a black hole. Modifications near the event horizon can impact the overtones, providing insights into the geometry of the event horizon. Overtones are stable against deformations of spacetime, distinguishing the event horizon from the surrounding environment. The larger energy contribution of overtones compared to echoes opens up new avenues for future observations.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2023)
Article
Astronomy & Astrophysics
R. A. Konoplya, Z. Stuchlik, A. Zhidenko, A. F. Zinhailo
Summary: We calculate the accurate quasinormal frequencies for a corrected quantum black hole using the coordinate-independent iterative procedure in the renormalization group theory, resulting in the Dymnikova regular black hole. We observe that the quantum correction has a minimal effect on the fundamental mode, but significantly impacts the overtones. This is due to the geometry deformation of the Schwarzschild black hole near the event horizon. In order to find precise values of overtones, we develop a general procedure to apply the Leaver method to metrics that are initially not expressed as rational functions.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: The fundamental quasinormal modes of black holes in higher-derivative gravity are moderately corrected by the Weyl term. The first several overtones are highly sensitive to even a relatively small Weyl correction, which might be important when representing the earlier stage of the black hole ringdown. In addition, a problem related to the analytical parametrized approximation of the numerical black hole solution in the Einstein-Weyl theory has been solved by extending the parametrization of the metric to higher orders.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: We present an improved Mathematica code that uses the Bernstein spectral method to compute quasinormal frequencies for a general class of black holes. The code can handle asymptotically flat, de Sitter, or anti-de Sitter asymptotic. The method is particularly efficient in searching for purely imaginary and unstable modes, and we demonstrate its effectiveness in detecting the instability region of a charged scalar field in the background of a charged asymptotically de Sitter dilatonic black hole. We show that the instability has a superradiant nature and is significantly influenced by the dilaton field.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: This paper investigates the quasinormal spectrum of gravitational perturbations of Schwarzschild-de Sitter black holes and finds a new branch of purely imaginary modes. When the ratio of the event horizon radius to the cosmological horizon approaches zero, these quasinormal modes approach modes of empty de Sitter spacetime.
Article
Astronomy & Astrophysics
M. S. Churilova, R. A. Konoplya, A. Zhidenko
Summary: This article studies the quasinormal modes of fields in the extreme Schwarzschild-de Sitter background. It is found that perturbations of fermionic fields do not satisfy the Pöschl-Teller effective potential, but quasinormal modes are still obtained analytically using the Frobenius method. An analytical formula for the quasinormal frequencies of near-extreme Schwarzschild-de Sitter black holes is derived, which is valid for both bosonic and fermionic fields. The analysis is further extended to the case of charged rotating black holes, resulting in a general analytical formula for quasinormal modes of fields with different spins in the near extreme Kerr-Newman-de Sitter spacetime.
Article
Astronomy & Astrophysics
Kirill A. Bronnikov, Roman A. Konoplya, Thomas D. Pappas
Summary: The study presents a general parametrization method for describing spacetimes of spherically symmetric Lorentzian, traversable wormholes, with validity that extends beyond the weak field region. Experimental results show that the parametrization provides high accuracy at the first order in most cases.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: The black hole solution in conformal Weyl gravity describes the evolution of gravitational field in different stages including Schwarzschild-like ringing, effective dark matter ringing, and de Sitter phase. The late-time behavior of the electromagnetic field is also different, as exponential tails appear even without the effective de Sitter term.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: The study explores asymptotically flat black holes in a general metric theory by constraining the metric class with additional symmetries, leading to the separation of variables in the Hamilton-Jacobi and Klein-Gordon equations. It is found that the black-hole shadow depends on a few deformation parameters if the metric functions change moderately near the black hole. Additionally, the shadow of a rotating black hole in the Einstein-dilaton-Gauss-Bonnet theory is well approximated when terms violating the separation of variables are neglected in the metric.
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.
