Pub Date : 2025-01-30DOI: 10.1088/1361-6382/ada867
Iberê Kuntz, Gregorio Paci and Omar Zanusso
It is well-known that the results by Bekenstein, Gibbons and Hawking on the thermodynamics of black holes can be reproduced quite simply in the Euclidean path integral approach to quantum gravity. The corresponding partition function is obtained semiclassically, ultimately requiring only the on-shell Einstein–Hilbert action with opportune asymptotic subtractions. We elaborate on the fact that the same expressions for the thermodynamical quantities can be obtained within teleparallel equivalent theories, based on either torsion or nonmetricity, by employing quasilocal relations. Notably, the bulk integrals of these theories do not vanish on-shell but rather result in boundary terms themselves. Asymptotic subtractions of the latter are able to cancel out the divergences, ultimately leading to Bekenstein–Gibbons–Hawking’s results. As a non-trivial cross-check, we compute the bulk integrals directly without reference to the boundary terms. While the result agrees with the previous method for the torsion-based teleparallel theory, it differs for the nonmetricity theory. Specifically, upon regularizing the bulk integral using a fiducial reference frame, we find that the semiclassical partition function vanishes. To address this problem, we propose a simple prescription for Schwarzschild black holes, which involves keeping the nonmetric connection arbitrary and imposing thermal equilibrium. Generalizations of the results to more general modified gravity theories with antisymmetric degrees of freedom are also discussed.
{"title":"Euclidean actions and static black hole entropy in teleparallel theories","authors":"Iberê Kuntz, Gregorio Paci and Omar Zanusso","doi":"10.1088/1361-6382/ada867","DOIUrl":"https://doi.org/10.1088/1361-6382/ada867","url":null,"abstract":"It is well-known that the results by Bekenstein, Gibbons and Hawking on the thermodynamics of black holes can be reproduced quite simply in the Euclidean path integral approach to quantum gravity. The corresponding partition function is obtained semiclassically, ultimately requiring only the on-shell Einstein–Hilbert action with opportune asymptotic subtractions. We elaborate on the fact that the same expressions for the thermodynamical quantities can be obtained within teleparallel equivalent theories, based on either torsion or nonmetricity, by employing quasilocal relations. Notably, the bulk integrals of these theories do not vanish on-shell but rather result in boundary terms themselves. Asymptotic subtractions of the latter are able to cancel out the divergences, ultimately leading to Bekenstein–Gibbons–Hawking’s results. As a non-trivial cross-check, we compute the bulk integrals directly without reference to the boundary terms. While the result agrees with the previous method for the torsion-based teleparallel theory, it differs for the nonmetricity theory. Specifically, upon regularizing the bulk integral using a fiducial reference frame, we find that the semiclassical partition function vanishes. To address this problem, we propose a simple prescription for Schwarzschild black holes, which involves keeping the nonmetric connection arbitrary and imposing thermal equilibrium. Generalizations of the results to more general modified gravity theories with antisymmetric degrees of freedom are also discussed.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"22 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-29DOI: 10.1088/1361-6382/ad9c0e
Ana Lorenzo-Medina and Thomas Dent
Despite the observation of nearly 100 compact binary coalescence (CBC) events up to the end of the Advanced gravitational-wave (GW) detectors’ third observing run (O3), there remain fundamental open questions regarding their astrophysical formation mechanisms and environments. Population analysis should yield insights into these questions, but requires careful control of uncertainties and biases. GW observations have a strong selection bias: this is due first to the dependence of the signal amplitude on the source’s (intrinsic and extrinsic) parameters, and second to the complicated nature of detector noise and of current detection methods. In this work, we introduce a new physically-motivated model of the sensitivity of GW searches for CBC events, aimed at enhancing the accuracy and efficiency of population reconstructions. In contrast to current methods which rely on re-weighting simulated signals (injections) via importance sampling, we model the probability of detection of binary black hole (BBH) mergers as a smooth, analytic function of source masses, orbit-aligned spins, and distance, fitted to accurately match injection results. The estimate can thus be used for population models whose signal distribution over parameter space differs significantly from the injection distribution. Our method has already been used in population studies such as reconstructing the BBH merger rate dependence on redshift.
{"title":"A physically modelled selection function for compact binary mergers in the LIGO-Virgo O3 run and beyond","authors":"Ana Lorenzo-Medina and Thomas Dent","doi":"10.1088/1361-6382/ad9c0e","DOIUrl":"https://doi.org/10.1088/1361-6382/ad9c0e","url":null,"abstract":"Despite the observation of nearly 100 compact binary coalescence (CBC) events up to the end of the Advanced gravitational-wave (GW) detectors’ third observing run (O3), there remain fundamental open questions regarding their astrophysical formation mechanisms and environments. Population analysis should yield insights into these questions, but requires careful control of uncertainties and biases. GW observations have a strong selection bias: this is due first to the dependence of the signal amplitude on the source’s (intrinsic and extrinsic) parameters, and second to the complicated nature of detector noise and of current detection methods. In this work, we introduce a new physically-motivated model of the sensitivity of GW searches for CBC events, aimed at enhancing the accuracy and efficiency of population reconstructions. In contrast to current methods which rely on re-weighting simulated signals (injections) via importance sampling, we model the probability of detection of binary black hole (BBH) mergers as a smooth, analytic function of source masses, orbit-aligned spins, and distance, fitted to accurately match injection results. The estimate can thus be used for population models whose signal distribution over parameter space differs significantly from the injection distribution. Our method has already been used in population studies such as reconstructing the BBH merger rate dependence on redshift.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"56 3 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-29DOI: 10.1088/1361-6382/ad9a48
Chiara Caprini, Oriol Pujolàs, Hippolyte Quelquejay-Leclere, Fabrizio Rompineve and Danièle A Steer
Third generation ground-based gravitational wave (GW) detectors, such as Einstein Telescope and Cosmic Explorer, will operate in the Hz frequency band, with a boost in sensitivity providing an unprecedented reach into primordial cosmology. Working concurrently with pulsar timing arrays in the nHz band, and LISA in the mHz band, these 3G detectors will be powerful probes of beyond the standard model particle physics on scales GeV. Here we focus on their ability to probe phase transitions (PTs) in the early Universe. We first overview the landscape of detectors across frequencies, discuss the relevance of astrophysical foregrounds, and provide convenient and up-to-date power-law integrated sensitivity curves for these detectors. We then present the constraints expected from GW observations on first order PTs and on topological defects (strings and domain walls), which may be formed when a symmetry is broken irrespective of the order of the phase transition. These constraints can then be applied to specific models leading to first order PTs and/or topological defects. In particular we discuss the implications for axion models, which solve the strong CP problem by introducing a spontaneously broken Peccei-Quinn (PQ) symmetry. For post-inflationary breaking, the PQ scale must lie in the GeV range, and so the signal from a first order PQ PT falls within reach of ground based 3G detectors. A scan in parameter space of signal-to-noise ratio in a representative model reveals their large potential to probe the nature of the PQ transition. Additionally, in heavy axion type models domain walls form, which can lead to a detectable GW background. We discuss their spectrum and summarise the expected constraints on these models from 3G detectors, together with SKA and LISA7.
{"title":"Primordial gravitational wave backgrounds from phase transitions with next generation ground based detectors","authors":"Chiara Caprini, Oriol Pujolàs, Hippolyte Quelquejay-Leclere, Fabrizio Rompineve and Danièle A Steer","doi":"10.1088/1361-6382/ad9a48","DOIUrl":"https://doi.org/10.1088/1361-6382/ad9a48","url":null,"abstract":"Third generation ground-based gravitational wave (GW) detectors, such as Einstein Telescope and Cosmic Explorer, will operate in the Hz frequency band, with a boost in sensitivity providing an unprecedented reach into primordial cosmology. Working concurrently with pulsar timing arrays in the nHz band, and LISA in the mHz band, these 3G detectors will be powerful probes of beyond the standard model particle physics on scales GeV. Here we focus on their ability to probe phase transitions (PTs) in the early Universe. We first overview the landscape of detectors across frequencies, discuss the relevance of astrophysical foregrounds, and provide convenient and up-to-date power-law integrated sensitivity curves for these detectors. We then present the constraints expected from GW observations on first order PTs and on topological defects (strings and domain walls), which may be formed when a symmetry is broken irrespective of the order of the phase transition. These constraints can then be applied to specific models leading to first order PTs and/or topological defects. In particular we discuss the implications for axion models, which solve the strong CP problem by introducing a spontaneously broken Peccei-Quinn (PQ) symmetry. For post-inflationary breaking, the PQ scale must lie in the GeV range, and so the signal from a first order PQ PT falls within reach of ground based 3G detectors. A scan in parameter space of signal-to-noise ratio in a representative model reveals their large potential to probe the nature of the PQ transition. Additionally, in heavy axion type models domain walls form, which can lead to a detectable GW background. We discuss their spectrum and summarise the expected constraints on these models from 3G detectors, together with SKA and LISA7.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"34 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-29DOI: 10.1088/1361-6382/ad9b67
João Baptista
Geodesics in general relativity describe the behaviour of test particles in a gravitational field. In 5D Kaluza–Klein, geodesics reproduce the Lorentz force motion of particles in an electromagnetic field. This paper studies geodesic motion on a higher-dimensional with background metrics encoding general 4D gauge fields and Higgs-like scalars. It shows that the classical mass and charge of a test particle become variable quantities when the geodesic traverses regions of spacetime with massive gauge fields, such as the weak force field, or with non-constant Higgs scalars. This agrees with the physical fact that interactions mediated by massive bosons can change the mass and charge of particles. The variation rates of mass and charge along a geodesic are given by natural geometric formulae. In regions where mass is preserved, there are additional constants of motion, one for every abelian or simple summand in the Killing algebra of K. The last part of the paper discusses traditional difficulties of Kaluza–Klein models, such as the low ratios in the 5D model. It suggests possible ways to circumvent them. It also remarks the naturalness of a model in which elementary particles always travel at the speed of light in higher dimensions.
{"title":"Test particles in Kaluza–Klein models","authors":"João Baptista","doi":"10.1088/1361-6382/ad9b67","DOIUrl":"https://doi.org/10.1088/1361-6382/ad9b67","url":null,"abstract":"Geodesics in general relativity describe the behaviour of test particles in a gravitational field. In 5D Kaluza–Klein, geodesics reproduce the Lorentz force motion of particles in an electromagnetic field. This paper studies geodesic motion on a higher-dimensional with background metrics encoding general 4D gauge fields and Higgs-like scalars. It shows that the classical mass and charge of a test particle become variable quantities when the geodesic traverses regions of spacetime with massive gauge fields, such as the weak force field, or with non-constant Higgs scalars. This agrees with the physical fact that interactions mediated by massive bosons can change the mass and charge of particles. The variation rates of mass and charge along a geodesic are given by natural geometric formulae. In regions where mass is preserved, there are additional constants of motion, one for every abelian or simple summand in the Killing algebra of K. The last part of the paper discusses traditional difficulties of Kaluza–Klein models, such as the low ratios in the 5D model. It suggests possible ways to circumvent them. It also remarks the naturalness of a model in which elementary particles always travel at the speed of light in higher dimensions.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"62 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-24DOI: 10.1088/1361-6382/ada865
Z Nekouee, S K Narasimhamurthy, B R Yashwanth and T Sanjay
The study of hairy black holes within Finsler space-time is performed based on a fundamental set of criteria. These requirements include the presence of a clearly defined event horizon and compliance with the strong energy condition for the characteristics outside the horizon. This examination is conducted through the gravitational decoupling method to describe the deformation of a Finslerian Schwarzschild (FSch) black hole due to the inclusion of additional arbitrary sources (scalar field, tensor field, fluidlike dark matter, etc). So, it is characterized by the primary hair ( ) where the parameter is linked to gauge transformations of the seed FSch metric and α is the deformation factor apart from flag curvature (λ) and mass (M). This study focuses on determining the black hole's temperature and heat capacity, which are crucial for understanding its thermodynamic properties. Additionally, we examine how the hairy parameters influence these thermodynamic characteristics, providing a deeper understanding of the interplay between the black hole's structure and its thermal behavior. Moreover, this paper investigates the null geodesics around the Finslerian hairy Schwarzschild black hole, where we obtain the physical parameters associated with these geodesics, including the effective potential, the photon sphere radius, and the impact parameter and investigate the effects of Finslerian parameter ε and hairy parameters ( ) on these values. This study aims to enhance our understanding of the structure of space-time and the behavior of light in proximity to black holes.
{"title":"Exploring null geodesic of Finslerian hairy black hole","authors":"Z Nekouee, S K Narasimhamurthy, B R Yashwanth and T Sanjay","doi":"10.1088/1361-6382/ada865","DOIUrl":"https://doi.org/10.1088/1361-6382/ada865","url":null,"abstract":"The study of hairy black holes within Finsler space-time is performed based on a fundamental set of criteria. These requirements include the presence of a clearly defined event horizon and compliance with the strong energy condition for the characteristics outside the horizon. This examination is conducted through the gravitational decoupling method to describe the deformation of a Finslerian Schwarzschild (FSch) black hole due to the inclusion of additional arbitrary sources (scalar field, tensor field, fluidlike dark matter, etc). So, it is characterized by the primary hair ( ) where the parameter is linked to gauge transformations of the seed FSch metric and α is the deformation factor apart from flag curvature (λ) and mass (M). This study focuses on determining the black hole's temperature and heat capacity, which are crucial for understanding its thermodynamic properties. Additionally, we examine how the hairy parameters influence these thermodynamic characteristics, providing a deeper understanding of the interplay between the black hole's structure and its thermal behavior. Moreover, this paper investigates the null geodesics around the Finslerian hairy Schwarzschild black hole, where we obtain the physical parameters associated with these geodesics, including the effective potential, the photon sphere radius, and the impact parameter and investigate the effects of Finslerian parameter ε and hairy parameters ( ) on these values. This study aims to enhance our understanding of the structure of space-time and the behavior of light in proximity to black holes.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"124 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Optimised alignment is important in optical systems, particularly in high-precision instrumentation such as gravitational wave detectors, in order to maximise the sensitivity. During operations, high performing optical wave-front sensing and feedback systems are used to maintain optical cavity performance. However, the need for an automated initial alignment process arises after maintenance or large environmental disturbances such as earthquakes, as it can be challenging to manually achieve optimised as well as consistent optical alignments. In this study, a machine learning control system is presented to determine the optimal input beam alignment of an optical cavity based on a digital camera stream of the transmitted cavity mode. We use convolutional neural networks to classify the cavity mode from its image, with 100% prediction accuracy for the desired mode. A genetic algorithm is applied to find experimental parameters that maximise the transmitted power of a chosen cavity mode. The system demonstrates consistent alignment outcomes that the median intensity over multiple trials exceeds 95% by the sixth generation of the algorithm. These results show that machine learning techniques can be implemented to automate the alignment process that is compatible for a broad range of optical resonator platforms.
{"title":"Automated alignment of an optical cavity using machine learning","authors":"Jiayi Qin, Katherine Kinder, Shreejit Jadhav, Praneel Chugh and Bram J J Slagmolen","doi":"10.1088/1361-6382/ada864","DOIUrl":"https://doi.org/10.1088/1361-6382/ada864","url":null,"abstract":"Optimised alignment is important in optical systems, particularly in high-precision instrumentation such as gravitational wave detectors, in order to maximise the sensitivity. During operations, high performing optical wave-front sensing and feedback systems are used to maintain optical cavity performance. However, the need for an automated initial alignment process arises after maintenance or large environmental disturbances such as earthquakes, as it can be challenging to manually achieve optimised as well as consistent optical alignments. In this study, a machine learning control system is presented to determine the optimal input beam alignment of an optical cavity based on a digital camera stream of the transmitted cavity mode. We use convolutional neural networks to classify the cavity mode from its image, with 100% prediction accuracy for the desired mode. A genetic algorithm is applied to find experimental parameters that maximise the transmitted power of a chosen cavity mode. The system demonstrates consistent alignment outcomes that the median intensity over multiple trials exceeds 95% by the sixth generation of the algorithm. These results show that machine learning techniques can be implemented to automate the alignment process that is compatible for a broad range of optical resonator platforms.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"61 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-24DOI: 10.1088/1361-6382/ada866
M-S Hartig, J Marmor, D George, S Paczkowski and J Sanjuan
The coupling of the angular jitter of the spacecraft and their sub-assemblies with the optical bench and the telescope into the interferometric length readout will be a major noise source in the LISA mission. We refer to this noise as tilt-to-length (TTL) coupling. It will be reduced directly by realignments, and the residual noise will then be subtracted in post-processing. The success of these mitigation strategies depends on an accurate computation of the TTL coupling coefficients. We present here a thorough analysis of the accuracy of the coefficient estimation under different jitter characteristics, angular readout noise levels, and gravitational wave sources. We analyze in which cases the estimates degrade using two estimators, the common least squares estimator and the instrumental variables estimator. Our investigations show that angular readout noise leads to a systematic bias of the least squares estimator, depending on the TTL coupling coefficients, jitter and readout noise level, while the instrumental variable estimator converges to an unbiased result as the data set length increases. We present an equation that predicts the estimation bias of the least squares method due to angular readout noise.
{"title":"Tilt-to-length coupling in LISA—uncertainty and biases","authors":"M-S Hartig, J Marmor, D George, S Paczkowski and J Sanjuan","doi":"10.1088/1361-6382/ada866","DOIUrl":"https://doi.org/10.1088/1361-6382/ada866","url":null,"abstract":"The coupling of the angular jitter of the spacecraft and their sub-assemblies with the optical bench and the telescope into the interferometric length readout will be a major noise source in the LISA mission. We refer to this noise as tilt-to-length (TTL) coupling. It will be reduced directly by realignments, and the residual noise will then be subtracted in post-processing. The success of these mitigation strategies depends on an accurate computation of the TTL coupling coefficients. We present here a thorough analysis of the accuracy of the coefficient estimation under different jitter characteristics, angular readout noise levels, and gravitational wave sources. We analyze in which cases the estimates degrade using two estimators, the common least squares estimator and the instrumental variables estimator. Our investigations show that angular readout noise leads to a systematic bias of the least squares estimator, depending on the TTL coupling coefficients, jitter and readout noise level, while the instrumental variable estimator converges to an unbiased result as the data set length increases. We present an equation that predicts the estimation bias of the least squares method due to angular readout noise.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"40 11 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-22DOI: 10.1088/1361-6382/ada90c
Samuel Blitz and Shahn Majid
Understanding the microscopic behavior of spacetime, in particular quantum uncertainty in the Ricci scalar, is critical for developing a theory of quantum gravity and perhaps solving the cosmological constant problem. To test this, we compute this quantity for a simple but exact discrete quantum gravity model based on a single plaquette of spacetime. Our results confirm initial speculations of Wheeler from 1955 in finding a UV divergence in the quantum uncertainty. We further show that this behavior is stable under renormalization, but potentially unstable with the introduction of a cosmological constant, suggesting that a bare cosmological constant is ruled out.
{"title":"Quantum curvature fluctuations and the cosmological constant in a single plaquette quantum gravity model","authors":"Samuel Blitz and Shahn Majid","doi":"10.1088/1361-6382/ada90c","DOIUrl":"https://doi.org/10.1088/1361-6382/ada90c","url":null,"abstract":"Understanding the microscopic behavior of spacetime, in particular quantum uncertainty in the Ricci scalar, is critical for developing a theory of quantum gravity and perhaps solving the cosmological constant problem. To test this, we compute this quantity for a simple but exact discrete quantum gravity model based on a single plaquette of spacetime. Our results confirm initial speculations of Wheeler from 1955 in finding a UV divergence in the quantum uncertainty. We further show that this behavior is stable under renormalization, but potentially unstable with the introduction of a cosmological constant, suggesting that a bare cosmological constant is ruled out.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"18 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-22DOI: 10.1088/1361-6382/ada714
David Sloan
In previous work I have shown that Herglotz actions reproduce the dynamics of classical mechanical theories which exhibit dynamical similarities. Recent work has shown how to extend field theories in both the Lagrangian and de Donder-Weyl formalism to contact geometry (Gaset et al 2020 Ann. Phys., NY414 168092; 2021 Rep. Math. Phys.87 347–68; 2022 arXiv:2211.17058). In this article I show how dynamical similarity applies in field theory. This is applied in both the Lagrangian and Hamiltonian frameworks, producing the contact equivalents. The result can be applied to general relativity where I demonstrate how to construct a complete description of the dynamics, equivalent to those derived from the Einstein–Hilbert action, without reference to the conformal factor.
在以前的工作中，我已经表明，赫格洛茨动作再现了经典力学理论的动力学，这些力学理论表现出动力学相似性。最近的工作展示了如何将拉格朗日和德·多德-魏尔形式论中的场论扩展到接触几何（Gaset et al . 2020）。理论物理。， ny414 168092；2021众议员数学。Phys.87 347 - 68;2022 arXiv: 2211.17058)。在这篇文章中，我将展示动力学相似性在场论中的应用。这适用于拉格朗日和哈密顿框架，产生接触当量。这个结果可以应用于广义相对论，在广义相对论中，我演示了如何构建一个完整的动力学描述，等同于那些从爱因斯坦-希尔伯特作用中推导出来的动力学描述，而不涉及保形因子。
{"title":"Dynamical similarity in field theories","authors":"David Sloan","doi":"10.1088/1361-6382/ada714","DOIUrl":"https://doi.org/10.1088/1361-6382/ada714","url":null,"abstract":"In previous work I have shown that Herglotz actions reproduce the dynamics of classical mechanical theories which exhibit dynamical similarities. Recent work has shown how to extend field theories in both the Lagrangian and de Donder-Weyl formalism to contact geometry (Gaset et al 2020 Ann. Phys., NY414 168092; 2021 Rep. Math. Phys.87 347–68; 2022 arXiv:2211.17058). In this article I show how dynamical similarity applies in field theory. This is applied in both the Lagrangian and Hamiltonian frameworks, producing the contact equivalents. The result can be applied to general relativity where I demonstrate how to construct a complete description of the dynamics, equivalent to those derived from the Einstein–Hilbert action, without reference to the conformal factor.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"105 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-01-20DOI: 10.1088/1361-6382/ada2d7
Batoul Banihashemi, Edgar Shaghoulian and Sanjit Shashi
We study the thermodynamics of Einstein gravity with vanishing cosmological constant subjected to conformal boundary conditions. Our focus is on comparing the series of subextensive terms to predictions from thermal effective field theory, with which we find agreement for the boundary theory on a spatial sphere, hyperbolic space, and flat space. We calculate the leading Wilson coefficients and observe that the first subextensive correction to the free energy is negative. This violates a conjectured bound on this coefficient in quantum field theory, which we interpret as a signal that gravity does not fully decouple in the putative boundary dual.
{"title":"Flat space gravity at finite cutoff","authors":"Batoul Banihashemi, Edgar Shaghoulian and Sanjit Shashi","doi":"10.1088/1361-6382/ada2d7","DOIUrl":"https://doi.org/10.1088/1361-6382/ada2d7","url":null,"abstract":"We study the thermodynamics of Einstein gravity with vanishing cosmological constant subjected to conformal boundary conditions. Our focus is on comparing the series of subextensive terms to predictions from thermal effective field theory, with which we find agreement for the boundary theory on a spatial sphere, hyperbolic space, and flat space. We calculate the leading Wilson coefficients and observe that the first subextensive correction to the free energy is negative. This violates a conjectured bound on this coefficient in quantum field theory, which we interpret as a signal that gravity does not fully decouple in the putative boundary dual.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"56 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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