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Non-trivial gravitational saddles have played a key role in the island proposal for the black hole information paradox. It is worth asking if non-trivial saddles exist in microscopic descriptions of black holes. We show this to be the case…

High Energy Physics - Theory · Physics 2024-08-09 Pranav Kumar , Swapnamay Mondal

In this work, we explore the connection between Casimir energy and an Absurdly Benign Traversable Wormhole, which in the literature has been considered only in the pioneering paper of Morris and Thorne. To have consistency with the Casimir…

General Relativity and Quantum Cosmology · Physics 2021-02-03 Remo Garattini

Firstly, we review the pointwise and averaged energy conditions, the quantum inequality and the notion of the ``volume integral quantifier'', which provides a measure of the ``total amount'' of energy condition violating matter. Secondly,…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Francisco S. N. Lobo

At first glance, thermodynamic properties of gravity with asymptotically AdS conditions and those with box boundary conditions, where the spatial section of the boundary is a sphere of finite radius, appear similar. Both exhibit a similar…

General Relativity and Quantum Cosmology · Physics 2024-05-13 Shoichiro Miyashita

Recently, a modified theory of gravity was presented, which consists of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini. The theory possesses extremely interesting features…

General Relativity and Quantum Cosmology · Physics 2012-12-20 Salvatore Capozziello , Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo

In gravitational thermodynamics, the entropy of a black hole with distinct surface gravities can be evaluated in a microcanonical ensemble. At the $WKB$ level, the entropy becomes the negative of the Euclidean action of the constrained…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Zhong Chao Wu

We reformulate the construction of wormhole solutions as perturbations around near-horizon geometries of near-extremal Reissner-Nordstr\"{o}m black holes in four dimensions and equal-angular-momenta Myers-Perry black holes in five…

General Relativity and Quantum Cosmology · Physics 2025-11-27 Takamasa Kanai , Kengo Maeda , Daisuke Yoshida

In this note we calculate the Casimir effect of free thermal gravitons in Einstein universe and discuss how it changes the entropy bound condition proposed recently by Verlinde [hep-th/0008140] as a higher dimensional generalization of…

High Energy Physics - Theory · Physics 2009-10-31 Feng-Li Lin

We investigate the connection between the entanglement system in Minkowski spacetime and the black hole using the scaling analysis. Here we show that the entanglement system satisfies the Bekenstein entropy bound. Even though the entropies…

General Relativity and Quantum Cosmology · Physics 2010-04-05 Yun Soo Myung

The statistical mechanics of a gas of Einstein-Kalb-Ramond wormholes is studied in this paper. The wormholes studied are the result of sewing together two Reissner-Nordstrom-type black hole metrics at their horizons. By requiring the…

General Relativity and Quantum Cosmology · Physics 2011-10-10 Paul H. Cox , Benjamin C. Harms , Shaoqi Hou

New results for scalar Casimir self-energies arising from interior modes are presented for the three integrable tetrahedral cavities. Since the eigenmodes are all known, the energies can be directly evaluated by mode summation, with a…

High Energy Physics - Theory · Physics 2012-10-12 E. K. Abalo , K. A. Milton , L. Kaplan

The Casimir force due to a massless scalar field satisfying Dirichlet boundary conditions may attract or repel a piston in the neck of a flask-like container. Using the world-line formalism this behavior is related to the competing…

Quantum Physics · Physics 2009-02-11 Martin Schaden

We derive analytic expressions for the Helmholtz free energy, Casimir force, and Casimir entropy for both one-dimensional and three-dimensional scalar fields with Dirichlet boundary conditions at finite temperature. We investigate the…

High Energy Physics - Theory · Physics 2025-05-27 Liang Chen , Yu-Jing Wang , Sheng-Yan Li

We study the Casimir vacuum energy density and the Casimir pressure for a massless scalar field confined between two nearby parallel plates in a slightly curved, static spacetime background, employing the weak field approximation in the…

General Relativity and Quantum Cosmology · Physics 2017-04-19 G. Lambiase , A. Stabile , An. Stabile

New results for scalar Casimir self-energies arising from interior modes are presented for the three integrable tetrahedral cavities. Since the eigenmodes are all known, the energies can be directly evaluated by mode summation, with a…

High Energy Physics - Theory · Physics 2015-06-03 E. K. Abalo , K. A. Milton , L. Kaplan

Traversable wormholes have traditionally been viewed as intrinsically topological entities in some multiply connected spacetime. Here, we show that topology is too limited a tool to accurately characterize a generic traversable wormhole: in…

General Relativity and Quantum Cosmology · Physics 2011-09-30 David Hochberg , Matt Visser

The Casimir energy is evaluated for massless scalar fields under Dirichlet or Neumann boundary conditions, and for the electromagnetic field with perfect conductor boundary conditions on one and two infinite parallel plates moving by…

High Energy Physics - Theory · Physics 2009-11-10 A. A. Saharian , R. S. Davtyan , A. H. Yeranyan

We assume a flat brane located at y=0, surrounded by an AdS space, and consider the 5D Einstein equations when the energy flux component of the energy-momentum tensor is related to the Hubble parameter through a constant Q. We calculate the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Iver Brevik , Jon-Mattis Borven , Sebastian Ng

A traversable wormhole generally violates the averaged null energy condition, usually requiring exotic matter. Recently, it has been found that the traversable wormhole can be realized by non-exotic matter in Einstein-Dirac-Maxwell theories…

High Energy Physics - Theory · Physics 2025-03-06 Hua-Chao Liu , Rong-Xin Miao

We analyze the Casimir densities and forces associated with a massive scalar quantum field confined between two parallel plates in a D-dimensional cosmic string spacetime. The plates are placed orthogonal to the string and the field obeys…

High Energy Physics - Theory · Physics 2018-05-03 E. R. Bezerra de Mello , A. A. Saharian , S. V. Abajyan