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International Journal of Modern Physics D最新文献

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Thermodynamics as a tool for (quantum) gravitational dynamics 热力学作为(量子)引力动力学的工具
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-19 DOI: 10.1142/s021827182342018x
A. Alonso-Serrano, Marek Liška
{"title":"Thermodynamics as a tool for (quantum) gravitational dynamics","authors":"A. Alonso-Serrano, Marek Liška","doi":"10.1142/s021827182342018x","DOIUrl":"https://doi.org/10.1142/s021827182342018x","url":null,"abstract":"The thermodynamics of local causal horizons has been shown to imply gravitational dynamics. In this essay, we discuss the principles underlying this observation, and its significance in our understanding of (quantum) gravity. We also show why the local thermodynamic methods cannot by themselves recover general relativity. Instead, they lead to the so-called Weyl transverse gravity. Because of this, local thermodynamic approaches avoid huge vacuum energy contributions to the cosmological constant. They even suggest a possible source for its small observed value. We also outline a way in which thermodynamics allows us to study low energy quantum gravitational effects. We arrive at quantum corrections to the gravitational equations which are suppressed by the Planck length squared.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45141288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Matter-Gravity Entanglement Entropy and the Second law for Black Holes 黑洞的物质引力纠缠熵和第二定律
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-19 DOI: 10.1142/s0218271823420026
B. S. Kay
{"title":"Matter-Gravity Entanglement Entropy and the Second law for Black Holes","authors":"B. S. Kay","doi":"10.1142/s0218271823420026","DOIUrl":"https://doi.org/10.1142/s0218271823420026","url":null,"abstract":"Hawking showed that a black hole formed by collapse will emit radiation and eventually disappear. We address the challenge to define an objective notion of physical entropy which increases throughout this process in a way consistent with unitarity. We have suggested that (instead of coarse-grained entropy) physical entropy is matter-gravity entanglement entropy and that this may offer an explanation of entropy increase both for the black hole collapse and evaporation system and also for other closed unitarily evolving systems. For this to work, the matter-gravity entanglement entropy of the late-time state of black hole evaporation would have to be larger than the entropy of the freshly formed black hole. We argue that this may possibly be the case due to (usually neglected) photon-graviton interactions.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47784949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The universality of black hole thermodynamics 黑洞热力学的普遍性
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-19 DOI: 10.1142/s0218271823410031
S. Mathur, Madhur Mehta
{"title":"The universality of black hole thermodynamics","authors":"S. Mathur, Madhur Mehta","doi":"10.1142/s0218271823410031","DOIUrl":"https://doi.org/10.1142/s0218271823410031","url":null,"abstract":"The thermodynamic properties of black holes — temperature, entropy and radiation rates — are usually associated with the presence of a horizon. We argue that any extremely compact object (ECO) must have the same thermodynamic properties. Quantum fields just outside the surface of an ECO have a large negative Casimir energy similar to the Boulware vacuum of black holes. If the thermal radiation emanating from the ECO does not fill the near-surface region at the local Unruh temperature, then we find that no solution of gravity equations is possible. In string theory, black holes microstates are horizonless quantum objects called fuzzballs that are expected to have a surface [Formula: see text] outside [Formula: see text]; thus the information puzzle is resolved while preserving the semiclassical thermodynamics of black holes.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42070221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Dynamical analysis of the Tsallis holographic dark energy models with event horizon as cut-off and interaction with matter 以视界为截止点和物质相互作用的Tsallis全息暗能量模型的动力学分析
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-17 DOI: 10.1142/s021827182350058x
A. Astashenok, A. Tepliakov
{"title":"Dynamical analysis of the Tsallis holographic dark energy models with event horizon as cut-off and interaction with matter","authors":"A. Astashenok, A. Tepliakov","doi":"10.1142/s021827182350058x","DOIUrl":"https://doi.org/10.1142/s021827182350058x","url":null,"abstract":"The model of generalized Tsallis holographic dark energy (which is known to be particular representative of Nojiri-Odintsov HDE) with event horizon as cut-off is investigated using methods of dynamical analysis. We take into consideration possible interaction with dark energy and matter in various forms. Critical points are determined. Cosmological evolution of the Universe depends from interaction parameters. If we use event horizon scale as cutoff quasi-de Sitter expansion is possible only for interaction of type $sim H(alpharho_{de}+betarho_{m})$ (where $H$ is the Hubble parameter). For interactions $sim rho_m rho_{de} /H$ and $sim H rho_{m}^{alpha}rho_{de}^{1-alpha}$ Universe eventually stops ($Hrightarrow 0$) or ends its existence in final singularity ($Hrightarrowinfty$). In first case fraction of dark energy tends to $1$ or constant value lesser than 1 because dynamical equilibrium between matter and dark energy is established on late times.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43267138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
BMS symmetry in gravity: Front form versus Instant form 重力中的BMS对称:正面形式与即时形式
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-16 DOI: 10.1142/s0218271823420014
S. Ananth, Sucheta Majumdar
{"title":"BMS symmetry in gravity: Front form versus Instant form","authors":"S. Ananth, Sucheta Majumdar","doi":"10.1142/s0218271823420014","DOIUrl":"https://doi.org/10.1142/s0218271823420014","url":null,"abstract":"In General Relativity, the allowed set of diffeomorphisms or gauge transformations at asymptotic infinity forms the BMS group, an infinite-dimensional extension of the Poincar'e group. We focus on the structure of the BMS group in two distinct forms of Hamiltonian dynamics - the instant and front forms. Both similarities and differences in these two forms are examined while emphasising the role of non-covariant approaches to symmetries in gravity.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63903076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Limits of a non-local quantum spacetime 非局域量子时空的极限
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-16 DOI: 10.1142/s021827182342021x
Dawood Kothawala
{"title":"Limits of a non-local quantum spacetime","authors":"Dawood Kothawala","doi":"10.1142/s021827182342021x","DOIUrl":"https://doi.org/10.1142/s021827182342021x","url":null,"abstract":"A generic implication of incorporating gravitational effects in the analysis of quantum measurements is the existence of a zero-point length of spacetime. This requires an inherently non-local description of spacetime, beyond the usual one based on metric $g_{ab}(x)$ etc. The quantum spacetime should instead be reconstructed from non-local bi-tensors of the form $mathscr{G}_{ab ldots i'j' ldots}(x,x')$. A deeper look then reveals a subtle interplay interplay between non-locality and the limit $Ghbar/c^3 to 0$. In particular, the so called emergent gravity paradigm -- in which gravitational dynamics/action/spacetime are emergent and characterised by an *entropy functional* -- arises as the Cheshire grin of a fundamentally non-local quantum spacetime. This essay describes the flow of metric with respect to Planck length, and proposes a novel action for the same.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47547806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The semiclassical limit of quantum gravity and the problem of time 量子引力的半经典极限和时间问题
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-16 DOI: 10.1142/S0218271823400035
R. I. A. Ona, M. B. Kalmykov, D. P. Kislyakova, T. P. Shestakova
{"title":"The semiclassical limit of quantum gravity and the problem of time","authors":"R. I. A. Ona, M. B. Kalmykov, D. P. Kislyakova, T. P. Shestakova","doi":"10.1142/S0218271823400035","DOIUrl":"https://doi.org/10.1142/S0218271823400035","url":null,"abstract":"The question about the appearance of time in the semiclassical limit of quantum gravity continues to be discussed in the literature. It is believed that a temporal Schrodinger equation for matter fields on the background of a classical gravitational field must be true. To obtain this equation, the Born - Oppenheimer approximation for gravity is used. However, the origin of time in this equation is different in works of various authors. For example, in the papers of Kiefer and his collaborators, time is a parameter along a classical trajectory of gravitational field; in the works of Montani and his collaborators the origin of time is introducing the Kuchar - Torre reference fluid; in the extended phase space approach the origin of time is the consequence of existing of the observer in a fixed reference frame. We discuss and compare these approaches. To make the calculations transparent, we illustrate them with a model of a closed isotropic universe. In each approach, one obtains some Schrodinger equation for matter fields with quantum gravitational corrections, but the form of the equation and the corrections depend on additional assumptions which are rather arbitrary. None of the approaches can explain how time had appeared in the Early Universe, since it is supposed that classical gravity and, therefore, classical spacetime had already come into being.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45338123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Conformal motions of anisotropic exact Bianchi type II models admitting energy conditions in f(T) gravity 承认f(T)重力能量条件的各向异性精确Bianchi II型模型的共形运动
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-16 DOI: 10.1142/s0218271823500578
S. Qazi, F. Hussain, M. Ramzan, S. Haq
{"title":"Conformal motions of anisotropic exact Bianchi type II models admitting energy conditions in f(T) gravity","authors":"S. Qazi, F. Hussain, M. Ramzan, S. Haq","doi":"10.1142/s0218271823500578","DOIUrl":"https://doi.org/10.1142/s0218271823500578","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41611877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pancakification and negative Hawking temperatures 煎饼化和负霍金温度
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-15 DOI: 10.1142/s0218271823420178
T. McMaken
{"title":"Pancakification and negative Hawking temperatures","authors":"T. McMaken","doi":"10.1142/s0218271823420178","DOIUrl":"https://doi.org/10.1142/s0218271823420178","url":null,"abstract":"Vacuum models of charged or spinning black holes possess two horizons, the inner of which has the oft-overlooked property that gravitational tidal forces initially spaghettifying a freely falling observer will eventually change signs and flatten the observer like a pancake. Inner horizons also induce a classical blueshift instability known as mass inflation, and a number of recent studies have found that inner horizons exhibit even stronger quantum singular behavior. In this essay we explore the quantum effect of Hawking radiation, which in the presence of compressive tidal forces seems to predict negative temperatures. By analyzing the interaction of quantum fields with black hole geometries, we can come to a closer semiclassical understanding of what really happens near a black hole's inner horizon.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43790984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Universality in Binary Black Hole Dynamics: An Integrability Conjecture 双黑洞动力学中的普适性:一个可积性猜想
IF 2.2 4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-05-15 DOI: 10.1142/s0218271823420051
J. Jaramillo, B. Krishnan, C. Sopuerta
{"title":"Universality in Binary Black Hole Dynamics: An Integrability Conjecture","authors":"J. Jaramillo, B. Krishnan, C. Sopuerta","doi":"10.1142/s0218271823420051","DOIUrl":"https://doi.org/10.1142/s0218271823420051","url":null,"abstract":"The waveform of a binary black hole coalescence appears to be both simple and universal. In this essay we argue that the dynamics should admit a separation into 'fast and slow' degrees of freedom, such that the latter are described by an integrable system of equations, accounting for the simplicity and universality of the waveform. Given that Painlev'e transcendents are a smoking gun of integrable structures, we propose the Painlev'e-II transcendent as the key structural element threading a hierarchy of asymptotic models aiming at capturing different (effective) layers in the dynamics. Ward's conjecture relating integrable and (anti)self-dual solutions can provide the avenue to encode background binary black hole data in (non-local) twistor structures.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42696753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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