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The macroscopic properties of compact stars in modified gravity theories can be significantly different from the general relativistic (GR) predictions. Within the gravitational context of scalar-tensor theories, with a scalar field $\phi$…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Juan M. Z. Pretel , Sergio E. Jorás , Ribamar R. R. Reis , Sergio B. Duarte , José D. V. Arbañil

Motivated by a recent experiment [L.Chomaz et al., Nature Physics 14, 442 (2018)], we perform numerical simulations of a dipolar Bose-Einstein Condensate (BEC) in a tubular confinement at T=0 within Density Functional Theory, where the…

Quantum Gases · Physics 2019-04-10 Santo Maria Roccuzzo , Francesco Ancilotto

We investigate static, spherically symmetric solutions in Einstein-scalar-Gauss-Bonnet gravity non-minimally coupled to a massless real scalar field, both in vacuum and in the presence of fermionic matter. Focusing on a specific quadratic…

General Relativity and Quantum Cosmology · Physics 2025-11-03 Roberto D. Alba Q. , Javier Chagoya , Armando A. Roque

First, the present work is concerned with generalising constructions and results in quantum field theory on curved spacetimes from the well-known case of the Klein-Gordon field to Dirac fields. To this end, the enlarged algebra of…

General Relativity and Quantum Cosmology · Physics 2010-10-22 Thomas-Paul Hack

In this work, we investigated a most general isotropic charged fluid solution for the Buchdahl model via a two-step method in $\mathscr{F}(Q)$-gravity framework for the first time. In this context, a linear function of the form…

General Relativity and Quantum Cosmology · Physics 2024-06-28 Sourav Chaudharya , Sunil Kumar Maurya , Jitendra Kumara , Ghulam Mustafa

The so-called Buchdahl limit is not yet fully understood in the context of theories of gravity beyond the Einsteinian framework. In this investigation, we generalize this limit for the case of static, spherically-symmetric, relativistic…

General Relativity and Quantum Cosmology · Physics 2025-04-14 Raul Carpio Fernandez , Alvaro de la Cruz-Dombriz

We consider a quasi two-dimensional atomic Bose Einstein condensate interacting with a near-resonant laser field that is back-reflected onto the condensate by a planar mirror. We show that this single-mirror optical feedback leads to an…

Atomic Physics · Physics 2018-08-22 Yong-Chang Zhang , Valentin Walther , Thomas Pohl

In this paper, we study the stellar structure in terms of alternative theory of gravity specially by f (R;T) gravity theory. Here, we consider the function f (R;T) = R+2VT where R is the Ricci scalar, T is the stress-energy momentum and V…

General Relativity and Quantum Cosmology · Physics 2021-06-24 J. Kumar , H. D. Singh , A. K. Prasad

We complete here a three-part study (see also arXiv:1506.08095 and 1508.00856) of how codimension-two objects back-react gravitationally with their environment, with particular interest in situations where the transverse `bulk' is…

High Energy Physics - Theory · Physics 2016-08-30 C. P. Burgess , Ross Diener , M. Williams

We compute the renormalised energy momentum tensor of a free scalar field coupled to gravity on an (n+1)-dimensional Einstein Static Universe (ESU), RxS^n, with arbitrary low energy effective operators (up to mass dimension n+1). A generic…

High Energy Physics - Theory · Physics 2008-11-26 Carlos A. R. Herdeiro , Raquel H. Ribeiro , Marco Sampaio

As a neutron star spins down, the gradual decrease of the centrifugal force produces a progressive increase of the density of any given fluid element in its interior. Since the ``chemical'' (or ``beta'') equilibrium state is determined by…

Astrophysics · Physics 2009-10-28 Andreas Reisenegger

Quantum stress-energy tensors of fields renormalized on a Schwarzschild background violate the classical energy conditions near the black hole. Nevertheless, the associated equilibrium thermodynamical entropy $\Delta S$ by which such fields…

General Relativity and Quantum Cosmology · Physics 2009-12-30 David Hochberg , Thomas Kephart , James W. York

While binary atomic Bose-Einstein condensates are typically prone to collapse under strong interspecies attraction, it has been shown that higher-order fluctuation corrections, known as Lee-Huang-Yang corrections, can stabilize the mixture.…

Quantum Gases · Physics 2025-08-25 Wen-Bin He , Su Yi , Thomas Busch

We compute the vacuum polarization associated with quantum massless fields around stars with spherical symmetry. The nonlocal contribution to the vacuum polarization is dominant in the weak field limit, and induces quantum corrections to…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Alejandro Satz , Francisco D. Mazzitelli , Ezequiel Alvarez

We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is…

Quantum Gases · Physics 2014-12-17 Serena Cenatiempo , Alessandro Giuliani

de Sitter spacetime and Bunch-Davies vacuum are a solution to the semiclassical Einstein-Schroedinger equations describing the evolution of spacetime geometry and a massive scalar quantum field with arbitrary coupling to curvature. The…

General Relativity and Quantum Cosmology · Physics 2008-03-24 C. Busch

In this work, we demonstrate that the Bochner integral representation of the Algebraic Riccati Equations (ARE) are well-posed without any compactness assumptions on the coefficient and semigroup operators. From this result, we then are able…

Numerical Analysis · Mathematics 2024-02-05 James Cheung

We aim to search for the connection between the spacetime with an invariant minimum speed so-called Symmetrical Special Relativity (SSR) with Lorentz violation and the Gravitational Bose Einstein Condensate (GBEC) as the central core of a…

General Physics · Physics 2020-10-20 Claudio Nassif Cruz , Rodrigo Francisco dos Santos , A. C. Amaro de Faria

The existence of both a minimum mass and a minimum density in nature, in the presence of a positive cosmological constant, is one of the most intriguing results in classical general relativity. These results follow rigorously from the…

General Relativity and Quantum Cosmology · Physics 2015-11-30 Piyabut Burikham , Krai Cheamsawat , Tiberiu Harko , Matthew J. Lake

Among the different methods to derive particle creation, finding the quantum stress tensor expectation value gives a covariant quantity which can be used for examining the back-reaction issue. However this tensor also includes vacuum…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Javad T. Firouzjaee , George F. R. Ellis