Classical and Quantum Gravity最新文献

{"title":"Gravity from thermodynamics in vacuum: Lorentz invariance and the role of Bel–Robinson tensor","authors":"Ana Alonso-Serrano and Marek Liška","doi":"10.1088/1361-6382/adecd6","DOIUrl":"https://doi.org/10.1088/1361-6382/adecd6","url":null,"abstract":"Thermodynamics of local causal horizons has been shown to encode the information necessary to derive the equations governing the gravitational dynamics. We have previously argued that, in the presence of matter, this derivation further implies quantum phenomenological corrections to gravitational dynamics. Herein, we study whether similar corrections also occur in vacuum. We show that, under the assumptions of locality and local Lorentz invariance of physics, the vacuum dynamics is prescribed by the Einstein equations. We also discuss an alternative paradigm which assumes the existence of a preferred direction of time (much like in Einstein-aether or Hořava–Lifshitz gravity). Then, we find an modified gravitational dynamics in which Ricci curvature is sourced by Bel–Robinson super-energy.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"66 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144669611","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}

{"title":"A directed continuous-wave search from Scorpius X-1 with the five-vector resampling technique","authors":"Francesco Amicucci, Paola Leaci, Pia Astone, Sabrina D’Antonio, Stefano Dal Pra, Matteo Di Giovanni, Luca D’Onofrio, Federico Muciaccia, Cristiano Palomba, Lorenzo Pierini and Akshat Singhal","doi":"10.1088/1361-6382/adecd7","DOIUrl":"https://doi.org/10.1088/1361-6382/adecd7","url":null,"abstract":"Continuous gravitational-wave signals (CWs), which are typically emitted by rapidly rotating neutron stars with non-axisymmetric deformations, represent particularly intriguing targets for the Advanced Laser Interferometer GW Observatory (LIGO)-Virgo-KAGRA detectors. These detectors operate within sensitivity bands that encompass more than half of the known pulsars in our galaxy existing in binary systems (i.e. over 417 pulsars), which are the targeted sources of this paper. However, the detection of these faint signals is especially challenged by the Doppler modulation due to the source’s orbital motion, typically described by five Keplerian parameters, which must be determined with high precision to effectively detect the signal. This modulation spreads the signal across multiple frequency bins, resulting in a notable reduction of signal-to-noise ratio and potentially hindering signal detection. To overcome this issue, a robust five-vector resampling data-analysis algorithm has been developed to conduct thorough directed/narrowband CW searches at an affordable computational cost. We employ this methodology for the first time to search for CWs from Scorpius X-1 in a selected region of the parameter space, using publicly available data from the third observing run of the Advanced LIGO-Virgo-KAGRA detectors. No statistically significant CW signals can be claimed. Hence, we proceeded setting 95% confidence-level upper limits in selected frequency bands and orbital parameter ranges, while also evaluating overall sensitivity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"17 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144652230","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}

{"title":"A Bogovskiǐ-type operator for Corvino–Schoen hyperbolic gluing","authors":"Piotr T Chruściel, Albachiara Cogo and Andrea Nützi","doi":"10.1088/1361-6382/adda88","DOIUrl":"https://doi.org/10.1088/1361-6382/adda88","url":null,"abstract":"We construct a solution operator for the linearized constant scalar curvature equation at hyperbolic space in dimension larger than or equal to two. The solution operator has good support propagation properties and gains two derivatives relative to standard norms. It can be used for Corvino–Schoen-type hyperbolic gluing, partly extending the recently introduced Mao–Oh–Tao gluing method to the hyperbolic setting.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"7 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144652165","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}

{"title":"Robust Bayesian inference with gapped LISA data using all-in-one TDI- ∞","authors":"Niklas Houba, Jean-Baptiste Bayle and Michele Vallisneri","doi":"10.1088/1361-6382/adeb3c","DOIUrl":"https://doi.org/10.1088/1361-6382/adeb3c","url":null,"abstract":"The Laser Interferometer Space Antenna (LISA), an European Space Agency L-class mission, is designed to detect gravitational waves in the millihertz frequency band, with operations expected to begin in the next decade. LISA will enable groundbreaking studies of astrophysical phenomena such as massive black hole mergers, extreme mass ratio inspirals, and compact binary systems. A key challenge in analyzing LISA’s data is the significant laser frequency noise, which must be suppressed using time-delay interferometry (TDI) during on-ground processing. Classical TDI mitigates this noise by algebraically combining phase measurements taken at different times and spacecraft. However, data gaps caused by instrumental issues or operational interruptions complicate the process. These gaps affect multiple TDI samples due to the time delays inherent to the algorithm, rendering surrounding measurements unusable for parameter inference and degrading overall data quality. In this paper, we apply the recently proposed variant of TDI known as TDI- to astrophysical parameter inference, focusing on the challenge posed by data gaps. TDI- frames the LISA likelihood numerically in terms of raw measurements, marginalizing over laser phase noises under the assumption of infinite noise variance. Additionally, TDI- is set up to incorporate and cancel other noise sources beyond laser noise, including optical bench motion, clock noise, and modulation noise, establishing it as an all-in-one TDI solution. The method gracefully handles measurement interruptions, removing the need to explicitly address discontinuities during gravitational-wave template matching. We integrate TDI- into a Bayesian framework, demonstrating its superior performance in scenarios involving data gaps. Compared to classical TDI, the method preserves signal integrity more effectively and is particularly interesting for low-latency applications, where the limited amount of available data makes data gaps particularly disruptive. The study’s results highlight the potential of TDI- to enhance LISA’s scientific capabilities, paving the way for more robust data analysis pipelines.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"208 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144652166","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}

{"title":"All-loop effective potential for arbitrary scalar models in curved space-time","authors":"V A Filippov, R M Iakhibbaev and D M Tolkachev","doi":"10.1088/1361-6382/adecd8","DOIUrl":"https://doi.org/10.1088/1361-6382/adecd8","url":null,"abstract":"In this paper we calculate the leading divergences of the effective potential for an arbitrary scalar theory on a curved spacetime background. Based on the recurrence relation between the leading poles following from the locality condition, we obtain a system of generalised renormalisation-group equations that can be studied numerically or analytically in some special cases. We study the simplest effective potentials for power-like models and give a comparison of them in the framework of cosmological phenomenology.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"12 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144652231","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}

{"title":"Dark energy due to quantum corrections to effective potential","authors":"V A Filippov, R M Iakhibbaev, D I Kazakov and D M Tolkachev","doi":"10.1088/1361-6382/adec34","DOIUrl":"https://doi.org/10.1088/1361-6382/adec34","url":null,"abstract":"In this paper we calculate quantum corrections to the effective potential in different models of inflationary cosmology. We show that quantum corrections lead to a modification of the initial potential uplifting its value at the minimum, which can be interpreted as a cosmological constant/dark energy. We concentrate on the models of α-attractors and show that one can naturally get small values of the cosmological constant. In the model of quintessence, the same mechanism modifies the value of dark energy at the present time.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"12 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144645252","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}

{"title":"Aspects of warped AdS3 geometries","authors":"Pierre Bieliavsky, Philippe Spindel and Raphaela Wutte","doi":"10.1088/1361-6382/ade7eb","DOIUrl":"https://doi.org/10.1088/1361-6382/ade7eb","url":null,"abstract":"We discuss the geometry of three-dimensional warped Anti-de Sitter spaces and quotients thereof, paying special attention to their underlying group manifold nature. We perform a systematic analysis of warped Anti-de Sitter geometries, focusing on their global properties and illustrating their occurrence as special solutions of various three-dimensional gravity theories.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"24 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639994","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}

{"title":"Fractional Schwarzschild–Tangherlini black hole with a fractal event horizon","authors":"S Jalalzadeh, H Moradpour, G R Jafari and P V Moniz","doi":"10.1088/1361-6382/adec32","DOIUrl":"https://doi.org/10.1088/1361-6382/adec32","url":null,"abstract":"We demonstrate that the implementation of the fractional and non-local Wheeler–DeWitt equation within the context of Schwarzschild geometry leads to the emergence of a Schwarzschild–Tangherlini black hole (BH), which is uniquely characterized by an event horizon that exhibits fractal properties and is defined by a non-integer dimension that lies in the continuum between the values of 1 and 2. Our calculations further reveal that this intriguing fractional BH may potentially possess a temperature that is substantially lower than that of a conventional BH, thereby suggesting a significant deviation from the expected thermodynamic properties of standard BHs. These remarkable characteristics, which are intrinsically linked to the non-integer dimensionality of the event horizon, likely arise from applying the Riesz fractional derivative as a sophisticated non-local operator, thus introducing fascinating dynamics into the theoretical framework of BH physics.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"669 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639995","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}

{"title":"Gravitational wave tails from soft theorem: a short review","authors":"Ashoke Sen","doi":"10.1088/1361-6382/adec33","DOIUrl":"https://doi.org/10.1088/1361-6382/adec33","url":null,"abstract":"If a set of massive objects collide in space and the fragments disperse, possibly forming black holes, then this process will emit gravitational waves. Computing the detailed gravitational wave-form associated with this process is a complicated problem, not only due to the non-linearity of gravity but also due to the fact that during the collision and subsequent fragmentation the objects could undergo complicated non-gravitational interactions. Nevertheless the classical soft graviton theorem determines the power law fall-off of the wave-form at late and early times, including logarithmic corrections, in terms of only the momenta of the incoming and outgoing objects without any reference to what transpired during the collision. In this short review I shall explain the results and very briefly outline the derivation of these results.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"5 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144645596","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}

{"title":"Beyond ΛCDM: how the Hubble tension challenges early Universe physics","authors":"Gawain Simpson, Krzysztof Bolejko and Stephen Walters","doi":"10.1088/1361-6382/adec35","DOIUrl":"https://doi.org/10.1088/1361-6382/adec35","url":null,"abstract":"Differences in the values of the Hubble constant obtained from the local Universe and the early Universe have resulted in a significant tension. This tension signifies that our understanding of cosmology (physical processes and/or cosmological data) is incomplete. Some of the suggested solutions include physics of the early Universe. In this paper we aim to investigate common features of various early-Universe solutions to the Hubble constant tension. The physics of the early Universe affects the size of the sound horizon which is probed with the Cosmic Microwave Background data. Within the standard model, the size of the horizon (within limits of current measurements) is affected by processes that could occur between (approximately) 1 d after the Big Bang and the last scattering instant. We focus on simple extensions incorporating Early Dark Energy (EDE) and show how such a model affects the inferred values of the Hubble constant. We compare this model to ΛCDM models using MCMC analysis, likelihoods over the parameter space and Bayesian evidence. The MCMC analysis shows that EDE leads to a decrease in the size of the sound horizon that is consistent with km s−1 Mpc−1 but we also show that MCMC analysis favours increasing redshift and proportion of EDE. The Bayesian evidence favours our EDE model for very narrow, finely-tuned parameter space. The ΛCDM model used for comparison has good evidence across a wide parameter space. We interpret this as an indication that more sophisticated models are required. We conclude that if the Hubble tension were to be related to the physics of the early Universe, EDE could be used as a window to explore conditions of the early Universe and extend our understanding of that era.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"8 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639999","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}