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Modified gravity and generalized second law (GSL) of thermodynamics are interesting topics in the modern cosmology. In this regard, we investigate the GSL of gravitational thermodynamics in the framework of modified Gauss-Bonnet gravity or…

General Relativity and Quantum Cosmology · Physics 2016-11-22 A. Abdolmaleki , T. Najafi

We investigate the validity of the generalized second law of thermodynamics, applying Barrow entropy for the horizon entropy. The former arises from the fact that the black-hole surface may be deformed due to quantum-gravitational effects,…

General Relativity and Quantum Cosmology · Physics 2021-09-16 Emmanuel N. Saridakis , Spyros Basilakos

We here propose a covariant entropy conjecture on cosmological dynamical horizon. After the formulation of our conjecture, we test its validity in adiabatically expanding universes with open, flat and closed spatial geometry, where our…

High Energy Physics - Theory · Physics 2008-11-26 Song He , Hongbao Zhang

Ten attempts to prove the Generalized Second Law of Thermodyanmics (GSL) are described and critiqued. Each proof provides valuable insights which should be useful for constructing future, more complete proofs. Rather than merely summarizing…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Aron C. Wall

This paper is concerned with necessary and sufficient second-order conditions for finite-dimensional and infinite-dimensional constrained optimization problems. Using a suitably defined directional curvature functional for the admissible…

Optimization and Control · Mathematics 2021-01-26 Constantin Christof , Gerd Wachsmuth

In this work, we have discussed the Maxwell's electrodynamics in non-linear forms in FRW universe. The energy density and pressure for non-linear electrodynamics have been written in the electro-magnetic universe. The Einstein's field…

General Physics · Physics 2012-08-29 Tanwi Bandyopadhyay , Ujjal Debnath

The propagation of general electronic quantum states provides information of the interaction of molecular systems with external driving fields. These can also offer understandings regarding non-adiabatic quantum phenomena. Well established…

Quantum Physics · Physics 2023-09-08 Martín A. Mosquera

We introduce a technique for applying quantum expanders in a distributed fashion, and use it to solve two basic questions: testing whether a bipartite quantum state shared by two parties is the maximally entangled state and disproving a…

Quantum Physics · Physics 2015-01-26 Dorit Aharonov , Aram W. Harrow , Zeph Landau , Daniel Nagaj , Mario Szegedy , Umesh Vazirani

We investigate the laws of thermodynamics in an accelerating universe driven by dark energy with a time-dependent equation of state. In the case we consider that the physically relevant part of the Universe is that envelopped by the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Bin Wang , Yungui Gong , Elcio Abdalla

The work deals with universal thermodynamics for flat FRW model, considering interacting $n-$fluid system. By introducing the state finder parameters, the feasible regions in the $\{r,s\}-$plane has been examined for the validity of the…

General Physics · Physics 2011-10-28 Nairwita Mazumder , Ritabrata Biswas , Subenoy Chakraborty

We present a game-theoretic perspective on the problems of quantum state estimation and quantum cloning. This enables us to show why the focus on universal machines and the different measures of success, as employed in previous works, are…

Quantum Physics · Physics 2007-05-23 Chiu Fan Lee , Neil F. Johnson

The present work deals with a detailed study of universal thermodynamics in different modified gravity theories. The validity of the generalized second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) of the Universe…

General Relativity and Quantum Cosmology · Physics 2016-11-02 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

Boundary conditions defining a generic isolated horizon are introduced. They generalize the notion available in the existing literature by allowing the horizon to have distortion and angular momentum. Space-times containing a black hole,…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Abhay Ashtekar , Christopher Beetle , Olaf Dreyer , Stephen Fairhurst , Badri Krishnan , Jerzy Lewandowski , Jacek Wisniewski

We address the question of why particular laws were selected for the universe, by proposing a mechanism for laws to evolve. Normally in physical theories, timeless laws act on time-evolving states. We propose that this is an approximation,…

High Energy Physics - Theory · Physics 2012-01-13 Lee Smolin

As a sequel to (Berman, 2008a), we show that the rotation of the Universe can be dealt by generalised Gaussian metrics, defined in this paper. Robertson-Walker's metric has been employed with proper-time, in its standard applications; the…

General Physics · Physics 2009-11-13 Marcelo Samuel Berman

In this article we propose a `second quantization' scheme especially suitable to deal with non-trivial, highly symmetric phase spaces, implemented within a more general Group Approach to Quantization, which recovers the standard Quantum…

High Energy Physics - Theory · Physics 2016-12-28 M. Calixto , V. Aldaya , M. Navarro

We outline the basic questions that are being studied in the theory of entanglement. Following a brief review of some of the main achievements of entanglement theory for finite-dimensional quantum systems such as qubits, we will consider…

Quantum Physics · Physics 2009-09-29 J. Eisert , M. B. Plenio

We explore a cyclic universe due to phantom and quintessence fields. We find that, in every cycle of the evolution of the universe, the phantom dominates the cosmic early history and quintessence dominates the cosmic far future. In this…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-02 Changjun Gao , Youjun Lu , You-Gen Shen

We investigate the generalized second law for two-dimensional black holes in equilibrium (Hartle-Hawking) and nonequilibrium (Unruh) with the heat bath surrounding the black holes. We obtain a simple expression for the change of total…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Jeongwon Ho

In our previous work, a relation between Tsukiyama problem about self homotopy equivalence was found by using a generalization of phantom map. In this note, fundamental result is established for such a generalization. This is the first time…

Algebraic Topology · Mathematics 2007-05-23 Jianzhong Pan , Moo Ha Woo
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