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Spotting Stasis in Cosmological Perturbations

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arXiv 2025年

作者： Dienes, Keith R. Heurtier, Lucien Hoover, Daniel Huang, Fei Paulsen, Anna Thomas, Brooks Department of Physics University of Arizona TucsonAZ85721 United States Department of Physics University of Maryland College ParkMD20742 United States Theoretical Particle Physics and Cosmology Group Physics Department King’s College London Strand LondonWC2R 2LS United Kingdom Department of Physics Lafayette College EastonPA18042 United States Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot7610001 Israel Brown Theoretical Physics Center Brown University ProvidenceRI02912 United States

As discussed in a number of recent papers, cosmological stasis is a phenomenon wherein the abundances of multiple cosmological energy components with different equations of state remain constant for an extended period despite the expansion of the universe. One of the most intriguing aspects of the stasis phenomenon is that it can give rise to cosmological epochs in which the effective equation-of-state parameter 〈w〉 for the universe is constant, but differs from the canonical values associated with matter, radiation, vacuum energy, etc. Indeed, during such a stasis epoch, the spatial average of the energy density of the universe evolves in precisely the same manner as it would have evolved if the universe were instead dominated by a perfect fluid with an equation-of-state parameter equal to 〈w〉. However, as we shall demonstrate, this equivalence is broken at the level of the perturbations of the energy density. To illustrate this point, we consider a stasis epoch involving matter and radiation and demonstrate that within this stasis background the density perturbations associated with a spectator matter component with exceedingly small energy density exhibit a power-law growth that persists across the entire duration of the stasis epoch. This growth can potentially lead to significant enhancements of structure at small scales. Such enhancements are not only interesting in their own right, but may also provide a way of observationally distinguishing between a stasis epoch and an epoch of perfect-fluid domination — even if the universe has the same equation of state in both cases. Copyright © 2025, The Authors. All rights reserved.

关键词： cosmology

The trace distance between density matrices, a nifty tool in new-physics searches

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arXiv 2025年

作者： Fabbrichesi, Marco Low, Matthew Marzola, Luca INFN Sezione di Trieste Via Valerio 2 TriesteI-34127 Italy Pittsburgh Particle Physics Astrophysics and Cosmology Center Department of Physics and Astronomy University of Pittsburgh Pittsburgh United States Laboratory of High-Energy and Computational Physics NICPB Rävala pst 10 Tallinn10143 Estonia Institute of Computer Science University of Tartu Narva mnt 18 Tartu51009 Estonia

Quantum information methods have been brought to bear on high-energy physics, including the study of entanglement and Bell nonlocality in collider experiments. Quantum information observables have also been employed to constrain possible new physics effects. We improve on this point by introducing quantum information tools routinely used to compare quantum states: the trace distance and the fidelity. We find that the former outperforms other quantum information observables considered in the literature and, together with the cross section, yields the strongest bounds on possible departures from the Standard Model. The power of the proposed methodology is demonstrated with three examples of new physics searches. The first concerns the chromomagnetic dipole moment of the top quark and yields the first bound computed by means of quantum tomography and actual experimental data. The other two examples use Monte Carlo simulations and set the projected limits on the anomalous couplings of the τ leptons at Belle and at a future collider-which is taken to be LEP3. For these new physics searches we also compare the sensitivity of the trace distance to those of other quantum information quantities like concurrence, magic, and the fidelity distance. In passing, we provide the first determinations of magic in colliders data by analyzing the top-quark pair production at the LHC and the charmonium decays. The significance is well above the 5σ level in both the cases. © 2025, CC BY.

关键词： Quantum entanglement

Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits

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science (New York, N.Y.) 2025年第6745期388卷 400-404页

作者： Zang, Weicheng Jung, Youn Kil Yee, Jennifer C. Hwang, Kyu-Ha Yang, Hongjing Udalski, Andrzej Sumi, Takahiro Gould, Andrew Mao, Shude Albrow, Michael D. Chung, Sun-Ju Han, Cheongho Ryu, Yoon-Hyun Shin, In-Gu Shvartzvald, Yossi Cha, Sang-Mok Kim, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Lee, Chung-Uk Lee, Dong-Joo Lee, Yongseok Park, Byeong-Gon Pogge, Richard W. Zhang, Xiangyu Kuang, Renkun Wang, Hanyue Zhang, Jiyuan Hu, Zhecheng Zhu, Wei Mróz, Przemek Skowron, Jan Poleski, Radosław Szymański, Michał K Soszyński, Igor Pietrukowicz, Paweł Kozłowski, Szymon Ulaczyk, Krzysztof Rybicki, Krzysztof A. Iwanek, Patryk Wrona, Marcin Gromadzki, Mariusz Abe, Fumio Barry, Richard Bennett, David P. Bhattacharya, Aparna Bond, Ian A. Fujii, Hirosane Fukui, Akihiko Hamada, Ryusei Hirao, Yuki Silva, Stela Ishitani Itow, Yoshitaka Kirikawa, Rintaro Koshimoto, Naoki Matsubara, Yutaka Miyazaki, Shota Muraki, Yasushi Olmschenk, Greg Ranc, Clément Rattenbury, Nicholas J. Satoh, Yuki Suzuki, Daisuke Tomoyoshi, Mio Tristram, Paul J. Vandorou, Aikaterini Yama, Hibiki Yamashita, Kansuke Department of Astronomy Tsinghua University Beijing China Solar Stellar and Planetary Physics Division Center for Astrophysics Harvard and Smithsonian Cambridge MA USA Optical Astronomy Division Korea Astronomy and Space Science Institute Daejeon South Korea Department of Astronomy and Space Science National University of Science and Technology Daejeon South Korea Department of Astronomy Westlake University Hangzhou China Astronomical Observatory University of Warsaw Warszawa Poland Department of Earth and Space Science Graduate School of Science Osaka University Osaka Japan Galaxies and Cosmology Max-Planck-Institute for Astronomy Heidelberg Germany Department of Astronomy Ohio State University Columbus OH United States Department of Physics and Astronomy University of Canterbury Christchurch New Zealand Department of Physics Chungbuk National University Cheongju South Korea Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot Israel School of Space Research Kyung Hee University South Korea Center for Large Telescopes Korea Astronomy and Space Science Institute Daejeon South Korea Center for Cosmology and AstroParticle Physics Ohio State University Columbus OH United States Department of Engineering Physics Tsinghua University Beijing China Astronomy Department Harvard University Cambridge MA United States Department of Physics University of Warwick Coventry United Kingdom Department of Astrophysics and Planetary Sciences Villanova University Villanova PA United States Institute for Space-Earth Environmental Research Nagoya University Nagoya Japan Exoplanets and Stellar Astrophysics Laboratory NASA Goddard Space Flight Center Greenbelt MD United States Department of Astronomy University of Maryland College Park MD United States Institute of Natural and Mathematical Sciences Massey University Auckland New Zealand Department of Earth and Planetary Science Graduate School of Science University of Tokyo

Exoplanets classified as super-Earths are commonly observed on short-period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to exoplanets on wide orbits. We observed the microlensing event OGLE-2016-BLG-0007, which indicates an exoplanet with a planet-to-star mass ratio roughly double the Earth-Sun mass ratio, on an orbit longer than Saturn's. We combined this event with a larger sample from a microlensing survey to determine the distribution of mass ratios for planets on wide orbits. We infer that there are ~0.35 super-Earth planets per star on Jupiter-like orbits. The observations are most consistent with a bimodal distribution, with separate peaks for super-Earths and gas giants. We suggest that this reflects differences in their formation processes.

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Higher-order chiral scalar from boundary reduction of 3d higher-spin gravity

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arXiv 2025年

作者： Chen, Calvin Yi-Ren Joung, Euihun Mkrtchyan, Karapet Yoon, Junggi Blackett Laboratory Imperial College LondonSW7 2AZ United Kingdom Leung Center for Cosmology and Particle Astrophysics Taipei10617 Taiwan Center for Theoretical Physics National Taiwan University Taipei10617 Taiwan Department of Physics College of Science Kyung Hee University Seoul02447 Korea Republic of Asia Pacific Center for Theoretical Physics POSTECH 77 Cheongam-ro Nam-gu Gyeongsangbuk-do Pohang- si37673 Korea Republic of School of Physics Korea Institute for Advanced Study 85 Hoegiro Dongdaemun-gu Seoul02455 Korea Republic of

We use a recently proposed covariant procedure to reduce the Chern-Simons action of three-dimensional higher-spin gravity to the boundary, resulting in a Lorentz covariant action for higher-order chiral scalars. After gauge-fixing, we obtain a higher-derivative action generalizing the s = 1 Floreanini-Jackiw and s = 2 Alekseev-Shatashvili actions to arbitrary spin s. For simplicity, we treat the case of general spin at the linearized level, while the full non-linear asymptotic boundary conditions are presented in component form for the SL(3, ) case. Finally, we extend the spin-3 linearized analysis to a background with non-trivial higher-spin charge and show that it has a richer structure of zero modes. © 2025, CC BY.

关键词： Asymptotic analysis

Search for Solar Boosted Dark Matter particles at the PandaX-4T Experiment

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Physical Review Letters 2025年第16期134卷 161003-161003页

作者： Guofang Shen Zihao Bo Wei Chen Xun Chen Yunhua Chen Zhaokan Cheng Xiangyi Cui Yingjie Fan Deqing Fang Zhixing Gao Lisheng Geng Karl Giboni Xunan Guo Xuyuan Guo Zichao Guo Chencheng Han Ke Han Changda He Jinrong He Di Huang Houqi Huang Junting Huang Ruquan Hou Yu Hou Xiangdong Ji Xiangpan Ji Yonglin Ju Chenxiang Li Jiafu Li Mingchuan Li Shuaijie Li Tao Li Zhiyuan Li Qing Lin Jianglai Liu Congcong Lu Xiaoying Lu Lingyin Luo Yunyang Luo Wenbo Ma Yugang Ma Yajun Mao Yue Meng Xuyang Ning Binyu Pang Ningchun Qi Zhicheng Qian Xiangxiang Ren Dong Shan Xiaofeng Shang Xiyuan Shao Manbin Shen Wenliang Sun Yi Tao Anqing Wang Guanbo Wang Hao Wang Jiamin Wang Lei Wang Meng Wang Qiuhong Wang Shaobo Wang Siguang Wang Wei Wang Xiuli Wang Xu Wang Zhou Wang Yuehuan Wei Weihao Wu Yuan Wu Mengjiao Xiao Xiang Xiao Kaizhi Xiong Yifan Xu Shunyu Yao Binbin Yan Xiyu Yan Yong Yang Peihua Ye Chunxu Yu Ying Yuan Zhe Yuan Youhui Yun Xinning Zeng Minzhen Zhang Peng Zhang Shibo Zhang Shu Zhang Tao Zhang Wei Zhang Yang Zhang Yingxin Zhang Yuanyuan Zhang Li Zhao Jifang Zhou Jiaxu Zhou Jiayi Zhou Ning Zhou Xiaopeng Zhou Yubo Zhou Zhizhen Zhou Haipeng An Haoming Nie School of Physics Beihang University Beijing 102206 China School of Physics and Astronomy Shanghai Jiao Tong University Key Laboratory for Particle Astrophysics and Cosmology (MoE) Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240 China New Cornerstone Science Laboratory Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 201210 China Shanghai Jiao Tong University Sichuan Research Institute Chengdu 610213 China Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province China Yalong River Hydropower Development Company Ltd. 288 Shuanglin Road Chengdu 610051 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University Zhuhai 519082 China Department of Physics Yantai University Yantai 264005 China Key Laboratory of Nuclear Physics and Ion-beam Application (MoE) Institute of Modern Physics Fudan University Shanghai 200433 China Peng Huanwu Collaborative Center for Research and Education Beihang University Beijing 100191 China International Research Center for Nuclei and Particles in the Cosmos and Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing 100191 China Southern Center for Nuclear-Science Theory (SCNT) Institute of Modern Physics Chinese Academy of Sciences Huizhou 516000 China SJTU Paris Elite Institute of Technology Shanghai Jiao Tong University Shanghai 200240 China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Physics University of Maryland College Park Maryland 20742 USA School of Physics Nankai University Tianjin 300071 China School of Physics Sun Yat-Sen University Guangzhou 510275 China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Hefei 230026 China Department of Modern Physics University of Science and Technology of China Hefei 230026 China Research Center for Particle Science and Technology

We present a novel constraint on light dark matter utilizing 1.54 metric ton/year of data acquired from the PandaX-4T dual-phase xenon time projection chamber. This constraint is derived through detecting electronic recoil signals resulting from the interaction with solar-enhanced dark matter flux. Low-mass dark matter particles, lighter than a few MeV/c2, can scatter with the thermal electrons in the Sun. Consequently, with higher kinetic energy, the boosted dark matter component becomes detectable via contact scattering with xenon electrons, resulting in a few keV energy deposition that exceeds the threshold of PandaX-4T. We calculate the expected recoil energy in PandaX-4T considering the Sun’s acceleration with heavy mediators and the detection capabilities of the xenon detector. The first experimental search results using the xenon detector yield the most stringent upper limits cross section of 3.51×10−39 cm2 at 0.08 MeV/c2 for a solar boosted dark matter mass ranging from 0.02 to 10 MeV/c2, achieving a 23-fold improvement compared with earlier experimental studies.

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Searching for Nearby Diffuse Dwarf Galaxies in the COSMOS Field

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arXiv 2025年

作者： Shi, DongDong Zheng, XianZhong Pan, Zhizheng Luo, Yu Deng, Hongxia Hua, Qunzhi Luo, Xinyu Wu, Qiming Center for Fundamental Physics School of Mechanics and Optoelectronic Physics Anhui University of Science and Technology Huainan232001 China Tsung-Dao Lee Institute Key Laboratory for Particle Physics Astrophysics and Cosmology Ministry of Education Shanghai Jiao Tong University Shanghai201210 China Purple Mountain Observatory Chinese Academy of Sciences 10 Yuan Hua Road Jiangsu Nanjing210023 China Department of Physics School of Physics and Electronics Hunan Normal University Changsha410081 China

It remains challenging to systematically survey nearby diffuse dwarf galaxies and address the formation mechanism of this population distinguishing from regular ones. We carry out a pilot search for these galaxies in the COSMOS field using the deep HST/F814W imaging data. We report three diffuse dwarf galaxies satisfying the criteria: (1) redshift z e > 1′′ . 0, and (3) central surface brightness µ0 > 24 mag arcsec−2. Two of the three galaxies, COSMOS-UDG1 and COSMOS-UDG2, are recognized as ultra-diffuse galaxies (UDGs) with redshift z = 0.130 and 0.049, respectively. The third galaxy, COSMOS-dw1, is spectroscopically confirmed as a dwarf galaxy at z = 0.004. We derive the physical properties through fitting their spectral energy distributions (SEDs) extracted from deep multiwavelength observations. COSMOS-dw1 has a stellar mass of 5.6+2−2.57 × 106 M☉, harboring neutral hydrogen gas of mass 4.90 ± 0.90 × 106 M☉, hinting that this galaxy may be in the nascent stages of quenching. The estimated dynamical mass of 3.4 × 107 M☉ further suggests that COSMOS-dw1 is predominantly of dark matter. COSMOS-UDG1 and COSMOS-UDG2 exhibit comparable stellar masses of ∼ 2 × 108 M☉. Notably, COSMOS-UDG1 is younger and more metal-rich than COSMOS-UDG2 and COSMOS-dw1. Conversely, COSMOS-UDG2 and COSMOS-dw1 have similar stellar metallicities, yet COSMOS-UDG2 is older than COSMOS-dw1. All three galaxies adhere to the stellar mass-metallicity relation (MZR) for dwarf galaxies in the local Universe, implying they belong to the dwarf galaxy population. © 2025, CC BY.

关键词： Stars

Constraining cosmological parameters using the pairwise kinematic Sunyaev-Zel’dovich effect with CMB-S4 and future galaxy cluster surveys

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Physical Review D 2025年第6期111卷 063541-063541页

作者： E. Schiappucci S. Raghunathan C. To F. Bianchini C. L. Reichardt N. Battaglia B. Hadzhiyska S. Kim J. B. Melin School of Physics University of Melbourne Parkville Victoria 3010 Australia Center for AstroPhysical Surveys National Center for Supercomputing Applications Urbana Illinois 61801 USA Center for Cosmology and Astro-Particle Physics The Ohio State University Columbus Ohio 43210 USA Kavli Institute for Particle Astrophysics and Cosmology Stanford University 452 Lomita Mall Stanford California 94305 USA Department of Physics Stanford University 382 Via Pueblo Mall Stanford California 94305 USA SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park California 94025 USA Department of Astronomy Cornell University Ithaca New York 14853 USA Physics Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Berkeley Center for Cosmological Physics Department of Physics University of California Berkeley California 94720 USA Department of Astronomy and Space Science Sejong University 209 Neungdong-ro Gwangjin-gu Seoul 05006 Republic of Korea Department of Physics and Astronomy Sejong University 209 Neungdong-ro Gwangjin-gu Seoul 05006 Republic of Korea Université Paris-Saclay CEA Département de Physique des Particules 91191 Gif-sur-Yvette France

We present a forecast of the pairwise kinematic Sunyaev-Zel’dovich (kSZ) measurement that will be achievable with the future CMB-S4 experiment. CMB-S4 is the next stage for ground-based cosmic microwave background experiments, with a planned wide-area survey that will observe approximately 50% of the sky. We construct a simulated sample of galaxy clusters that have been optically selected in a Legacy Survey of Space and Time–like survey and have spectroscopic redshifts. For this cluster sample, assuming the likelihood is Gaussian, we predict that CMB-S4 will reject the null hypothesis of zero pairwise kSZ signal at 36σ. We estimate the effects of systematic uncertainties such as scatter in the mass-richness scaling relation and cluster miscentering. We find that these effects can reduce the signal-to-noise ratio of the CMB-S4 pairwise kSZ measurement by 20%. We explore the constraining power of the measured kSZ signal in combination with measurements of the galaxy clusters’ thermal SZ emission on two extensions to the standard cosmological model. The first extension allows the dark energy equation of state w to vary. We find the CMB-S4 pairwise kSZ measurement yields a modest reduction in the uncertainty on w by a factor of 1.36 over the Planck’s 2018 uncertainty. The second extension tests general relativity by varying the growth index γ. We find that CMB-S4’s pairwise kSZ measurement will yield a 28σ constraint on γ and strongly constrain alternative theories of gravity.

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Light cone distribution amplitude for the Λ baryon from lattice QCD

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Physical Review D 2025年第3期111卷 034510-034510页

作者： Min-Huan Chu Haoyang Bai Jun Hua Jian Liang Xiangdong Ji Andreas Schäfer Yushan Su Wei Wang Xiaonu Xiong INPAC Key Laboratory for Particle Astrophysics and Cosmology (MOE) Shanghai Key Laboratory for Particle Physics and Cosmology School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Yang Yuanqing Scientific Computering Center Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240 China Faculty of Physics Adam Mickiewicz University ulica Uniwersytetu Poznańskiego 2 61-614 Poznań Poland Institute of High Energy Physics CAS Beijing 100049 China School of Physics University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter Institute of Quantum Matter South China Normal University Guangzhou 510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Guangdong Provincial Key Laboratory of Nuclear Science Southern Nuclear Science Computing Center South China Normal University Guangzhou 510006 China Department of Physics University of Maryland College Park Maryland 20742 USA Institut für Theoretische Physik Universität Regensburg D-93040 Regensburg Germany Southern Center for Nuclear-Science Theory (SCNT) Institute of Modern Physics Chinese Academy of Sciences Huizhou 516000 Guangdong Province China School of Physics Central South University Changsha 418003 China

We calculate the leading-twist light cone distribution amplitudes of the Λ(uds) baryon using lattice QCD methods within the framework of large-momentum effective theory. Our numerical computations are carried out with Nf=2+1 stout smeared clover fermions and a Symanzik gauge action on a lattice with spacing a=0.077 fm and a pion mass of 303 MeV. To approach the large-momentum region, we simulate the equal-time correlations with the hadron momentum Pz={2.52,3.02,3.52} GeV. We investigate the analytic properties of the baryon quasidistribution amplitude in coordinate space and validate them through our lattice calculations. After renormalization and extrapolation, we present results for the three-dimensional distribution in momentum fractions of the two light quarks. Based on these findings, we briefly discuss the phenomenological impact on weak decays of Λb and outline potential systematic uncertainties that can be improved in the future. This work lays the theoretical foundation for accessing baryon light cone distribution amplitudes from lattice QCD.

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Constraining parity and Lorentz violations in gravity with future ground- and space-based gravitational wave detectors

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Physical Review D 2025年第10期111卷 104012-104012页

作者： Bo-Yang Zhang Tao Zhu Jian-Ming Yan Jing-Fei Zhang Xin Zhang Key Laboratory of Cosmology and Astrophysics (Liaoning) College of Sciences Northeastern University Shenyang 110819 China Institute for Theoretical Physics and Cosmology Zhejiang University of Technology Hangzhou 310032 China United Center for Gravitational Wave Physics (UCGWP) Zhejiang University of Technology Hangzhou 310032 China Key Laboratory of Data Analytics and Optimization for Smart Industry (Ministry of Education) Northeastern University Shenyang 110819 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang 110819 China

The future ground- and space-based gravitational wave (GW) detectors offer unprecedented opportunities to test general relativity (GR) with greater precision. In this work, we investigate the capability of future ground-based GW detectors, the Einstein Telescope (ET) and the Cosmic Explorer (CE), and space-based GW detectors, LISA, Taiji, and TianQin, for constraining parity and Lorentz violations in gravity. We inject several typical GW signals from compact binary systems into GW detectors and perform Bayesian inferences with the modified waveforms with parity and Lorentz-violating effects. These effects are modeled in the amplitude and phase corrections to the GW waveforms with their frequency-dependence described by factors βν, βμ, βν¯, and βμ¯. Our results show that the combined observations of ET and CE will impose significantly tighter bounds on the energy scale of parity and Lorentz violations (MPV and MLV) compared to those given by LIGO-Virgo-KAGRA (LVK) detectors. For cases with positive values of βν, βμ, βν¯, and βμ¯, the constraints on MPV and MLV from ground-based detectors are tighter than those from the space-based detectors. For the case of βμ=−1 space-based GW detectors provide constraints on MPV that are better than current LVK observations and comparable to those from ET and CE. Additionally, space-based detectors exhibit superior sensitivity in constraining MLV for βμ¯=−2 case, which is approximately 3 orders of magnitude tighter than those from ground-based GW detectors. This scenario also enables bounds on the graviton mass at mg≲10−35 GeV. These findings highlight the promising role of future GW observatories in probing fundamental physics beyond GR.

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