Article
Physics, Particles & Fields
Raghvendra Singh, Dawood Kothawala
Summary: By constructing a metric g<^>(ab) with Euclidean signature in a specific domain and a transition to Lorentzian regime on a hypersurface sigma orthogonal to the vector field u(a), we explore the implications of this geometry for thermal effects in curved spacetimes. The results obtained using g<^>(ab) differ from those obtained through conventional Euclidean methods, revealing additional terms in the entropy expression and a comparison between holonomy and temperature.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Caio C. Holanda Ribeiro, Sang-Shin Baak, Uwe R. Fischer
Summary: We propose a theoretical model of a finite-size quasi-one-dimensional Bose-Einstein condensate with coherent source and drain to create a stationary sonic black hole. Our analysis focuses on the condensate's resilience against quantum fluctuations and shows the occurrence of dynamical instabilities similar to black hole-white hole pairs. By exploring the instabilities' dependence on system parameters, we identify windows of potentially infinite black hole lifetimes. Using the quantum depletion of the condensate as a diagnostic tool, we validate the use of Bogoliubov theory in describing the analog Hawking process and discover novel signatures of Hawking radiation inside and outside the event horizon in the depleted cloud.
Article
Physics, Multidisciplinary
Matthew D. Horner, Andrew Hallam, Jiannis K. Pachos
Summary: The interface between different quantum phases of matter can lead to new physics, such as exotic topological phases or nonunitary conformal field theories. This study explores the interface between two spin chains in different chiral phases. Surprisingly, the mean field theory approximation of this interacting composite system can be described using Dirac fermions in a curved space-time geometry. The interface between the two phases represents a black hole horizon. Analytical and numerical methods confirm this representation, and a striking prediction emerges regarding thermalization at the interface.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
S. Banik, M. Gutierrez Galan, H. Sosa-Martinez, M. Anderson, S. Eckel, I. B. Spielman, G. K. Campbell
Summary: This study experimentally measures Hubble attenuation and amplification in toroidally shaped Bose-Einstein condensates and finds that the observed effects depend on the temporal phase of the phonon field, indicating nonadiabatic dynamics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Joshua Foo, Cemile Senem Arabaci, Magdalena Zych, Robert B. Mann
Summary: Within the framework of a unified theory of quantum gravity, this study examines the effects of quantum superpositions of different spacetimes, termed as spacetime super-positions, which cannot be related by a global coordinate transformation. By coupling quantum matter to fields on a periodic Minkowski spacetime background, the field-theoretic effects produced by such spacetimes can be measured theoretically. The results demonstrate that the detector's response exhibits discontinuous resonances at rational ratios of the superposed periodic length scale.
Article
Physics, Multidisciplinary
Sam Patrick, Harry Goodhew, Cisco Gooding, Silke Weinfurtner
Summary: Research has shown that fluid mechanical analogue black hole systems exhibit significant global mass changes in the presence of waves, leading to the possibility of studying backreaction with the presence of a dynamical metric.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Ren Tsuda, Shinya Tomizawa, Ryotaku Suzuki
Summary: We propose a new simple model of an acoustic black hole in a thin tube by utilizing the difference in gravitational potential to generate transonic flow. The analytical solution for the Euler equations can be obtained in our transonic flow model, providing an exact solution in terms of a height function for the monatomic case with gamma 1/4 5/3. By the near-sonic approximation, we find a simple form for arbitrary gamma. Additionally, two analytic solutions describing a backward wave and a forward wave are obtained, demonstrating the existence of sonic horizons.
Article
Astronomy & Astrophysics
Pratik Ghosal, Rajarshi Ray
Summary: The nonthermal correction to the emission probability of particles from black holes is significant as it helps determine the probability of complete black hole evaporation and matches the initial entropy of the black hole. The study reveals that this probability distribution resembles Wien's displacement law for blackbody radiation.
Article
Astronomy & Astrophysics
Scott L. Todd, Giacomo Pantaleoni, Valentina Baccetti, Nicolas C. Menicucci
Summary: The study investigates a simple toy model of particle scattering in the flat spacetime limit of an analogue-gravity model. By performing a sonic analogue to Compton scattering, in-universe observers can determine if they are in motion with respect to their medium and find their velocity with respect to the medium. Through the interaction between the phonon field and the external particle, the Lorentz symmetry of the speed of sound in the medium is explored.
Article
Astronomy & Astrophysics
Jun Feng, Jing-Jun Zhang
Summary: In this Letter, the authors use quantum Fisher information (QFI) to explore the thermal nature of the Unruh effect from both local and global perspectives. They find that the QFI is a time-evolving function of the detector's energy gap, Unruh temperature, and particularities of the background field. The results demonstrate the global side of Unruh's thermality and show that the different ways for the detector to approach the same thermal equilibrium are encoded in the corresponding time-evolution of the QFI. The authors also investigate the robustness of the QFI against Unruh decoherence and its potential applications in practical quantum estimation tasks.
Article
Physics, Particles & Fields
Sareh Eslamzadeh, Javad T. Firouzjaee, Kourosh Nozari
Summary: In this paper, we investigate the 4D Einstein-Gauss-Bonnet black hole and its thermodynamics. The study includes the analysis of three different asymptotic spacetimes and the correlation between emission modes and temperature. The results show interesting behaviors of temperature and emission in different spacetime backgrounds.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Satadal Datta, Uwe R. Fischer
Summary: This article discusses the propagation of nonlinear sound waves in a perfect fluid at rest and proposes an experimental protocol for observing acoustic gravitational wave memory.
Article
Physics, Multidisciplinary
Stephen Eckel, Ted Jacobson
Summary: The theoretical analysis of an expanding ring-shaped Bose-Einstein condensate reveals that expansion causes the phonon frequency to cool and the amplitude to weaken. This behavior is analogous to the redshifting and Hubble friction for quantum fields in the expanding universe, and is consistent with recent experimental and theoretical results. This study demonstrates the applicability of action-based dimensional reduction methods in various settings and perturbation expansions.
Article
Physics, Particles & Fields
Bei Sha, Zhi-E Liu
Summary: In this study, the tunneling radiation characteristics of fermions and bosons in Vaidya-Bonner de Sitter black hole space-time were corrected by considering Lorentz symmetry breaking theory. The new modified forms of Dirac equation for fermions with spin 1/2 and Klein-Gordon equation for bosons in the curved space-time of the black hole were obtained. Through solving these equations, new and corrected expressions for surface gravity, Hawking temperature, and tunneling rate of the black hole were obtained and discussed.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Jingbo Wang
Summary: Hawking radiation is a crucial feature of quantum black holes, leading to the information loss paradox and offering a significant clue for the unification of quantum mechanics and general relativity. Previous research used boundary scalar fields to determine the microstates of BTZ and Kerr black holes, contributing to the explanation of Bekenstein-Hawking entropy. This study demonstrates that Hawking radiation can also be derived from these scalar fields. It is a mixture of thermal radiation from right- and left-moving sectors at different temperatures. Based on this finding, a straightforward solution is proposed for the information loss paradox in static BTZ and Schwarzschild black holes, suggesting that Hawking radiation is pure due to entanglement between the left-moving sector and the right-moving sector. This entanglement might be detectable in an analogue black hole in the near future.
Article
Astronomy & Astrophysics
Shailesh Kulkarni
CLASSICAL AND QUANTUM GRAVITY
(2008)
Article
Physics, Particles & Fields
Wontae Kim, Shailesh Kulkarni
EUROPEAN PHYSICAL JOURNAL C
(2013)
Article
Astronomy & Astrophysics
Rabin Banerjee, Sunandan Gangopadhyay, Shailesh Kulkarni
GENERAL RELATIVITY AND GRAVITATION
(2010)
Article
Astronomy & Astrophysics
Rabin Banerjee, Shailesh Kulkarni
Article
Astronomy & Astrophysics
Rabin Banerjee, Shailesh Kulkarni
Article
Astronomy & Astrophysics
Sashideep Gutti, Shailesh Kulkarni, L. Sriramkumar
Article
Physics, Particles & Fields
Shailesh Kulkarni, Bum-Hoon Lee, Chanyong Park, Raju Roychowdhury
JOURNAL OF HIGH ENERGY PHYSICS
(2012)
Article
Physics, Particles & Fields
Shailesh Kulkarni, Bum-Hoon Lee, Jae-Hyuk Oh, Chanyong Park, Raju Roychowdhury
JOURNAL OF HIGH ENERGY PHYSICS
(2013)
Article
Physics, Particles & Fields
Wontae Kim, Shailesh Kulkarni, Sang-Heon Yi
JOURNAL OF HIGH ENERGY PHYSICS
(2013)
Article
Astronomy & Astrophysics
Rabin Banerjee, Subir Ghosh, Shailesh Kulkarni
Article
Physics, Particles & Fields
Rabin Banerjee, Shailesh Kulkarni, Saurav Samanta
JOURNAL OF HIGH ENERGY PHYSICS
(2006)
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.
