{"title":"Newtonian noise introduced by impellers in LIGO Voyager and Cosmic Explorer gravitational wave observatories","authors":"J A M Reis, E L Bonilla and O D Aguiar","doi":"10.1088/1361-6382/adbcf3","DOIUrl":"https://doi.org/10.1088/1361-6382/adbcf3","url":null,"abstract":"Third generation ground-based gravitational wave detectors are proposing the use of cryogenics. The low-temperature regime will require a cooling-down system capable of removing heat from test masses and maintaining its low temperature. The present study analyzes the Newtonian noise introduced by rotating impellers used in a cooling-down system with sub-cooled nitrogen circulating in a loop. In order to calculate this noise, a computational model was developed and the results were compared to the LIGO Voyager and Cosmic Explorer design sensitivity curves. For a system using two impellers having three blades each, the model shows that this Newtonian noise is always below the sensitivity curve if their distance to the test mass center is greater than 2.3 m for LIGO Voyager and 2.4 m for Cosmic Explorer. In addition, our calculations showed zero noise values for specific impeller’s locations, depending on the blade number. This revealed a new region where it is possible to minimize the noise.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"17 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841266","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}
S Soni, B K Berger, D Davis, F Di Renzo, A Effler, T A Ferreira, J Glanzer, E Goetz, G González, A Helmling-Cornell, B Hughey, R Huxford, B Mannix, G Mo, D Nandi, A Neunzert, S Nichols, K Pham, A I Renzini, R M S Schofield, A Stuver, M Trevor, S Álvarez-López, R Beda, C P L Berry, S Bhuiyan, L Blagg, R Bruntz, S Callos, M Chan, P Charlton, N Christensen, G Connolly, R Dhatri, J Ding, V Garg, K Holley-Bockelmann, S Hourihane, K Jani, K Janssens, S Jarov, A M Knee, A Lattal, Y Lecoeuche, T Littenberg, A Liyanage, B Lott, R Macas, D Malakar, K McGowan, J McIver, M Millhouse, L Nuttall, D Nykamp, I Ota, C Rawcliffe, B Scully, J Tasson, A Tejera, S Thiele, R Udall, C Winborn, Z Yarbrough, Z Zhang, Y Zheng, R Abbott, I Abouelfettouh, R X Adhikari, A Ananyeva, S Appert, K Arai, N Aritomi, S M Aston, M Ball, S W Ballmer, D Barker, L Barsotti, J Betzwieser, G Billingsley, S Biscans, N Bode, E Bonilla, V Bossilkov, A Branch, A F Brooks, D D Brown, J Bryant, C Cahillane, H Cao, E Capote..
{"title":"LIGO Detector Characterization in the first half of the fourth Observing run","authors":"S Soni, B K Berger, D Davis, F Di Renzo, A Effler, T A Ferreira, J Glanzer, E Goetz, G González, A Helmling-Cornell, B Hughey, R Huxford, B Mannix, G Mo, D Nandi, A Neunzert, S Nichols, K Pham, A I Renzini, R M S Schofield, A Stuver, M Trevor, S Álvarez-López, R Beda, C P L Berry, S Bhuiyan, L Blagg, R Bruntz, S Callos, M Chan, P Charlton, N Christensen, G Connolly, R Dhatri, J Ding, V Garg, K Holley-Bockelmann, S Hourihane, K Jani, K Janssens, S Jarov, A M Knee, A Lattal, Y Lecoeuche, T Littenberg, A Liyanage, B Lott, R Macas, D Malakar, K McGowan, J McIver, M Millhouse, L Nuttall, D Nykamp, I Ota, C Rawcliffe, B Scully, J Tasson, A Tejera, S Thiele, R Udall, C Winborn, Z Yarbrough, Z Zhang, Y Zheng, R Abbott, I Abouelfettouh, R X Adhikari, A Ananyeva, S Appert, K Arai, N Aritomi, S M Aston, M Ball, S W Ballmer, D Barker, L Barsotti, J Betzwieser, G Billingsley, S Biscans, N Bode, E Bonilla, V Bossilkov, A Branch, A F Brooks, D D Brown, J Bryant, C Cahillane, H Cao, E Capote..","doi":"10.1088/1361-6382/adc4b6","DOIUrl":"https://doi.org/10.1088/1361-6382/adc4b6","url":null,"abstract":"Progress in gravitational-wave (GW) astronomy depends upon having sensitive detectors with good data quality. Since the end of the Laser Interferometer Gravitational-Wave Observatory-Virgo-KAGRA third Observing run in March 2020, detector-characterization efforts have lead to increased sensitivity of the detectors, swifter validation of GW candidates and improved tools used for data-quality products. In this article, we discuss these efforts in detail and their impact on our ability to detect and study GWs. These include the multiple instrumental investigations that led to reduction in transient noise, along with the work to improve software tools used to examine the detectors data-quality. We end with a brief discussion on the role and requirements of detector characterization as the sensitivity of our detectors further improves in the future Observing runs.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"21 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836932","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}
Alexander F Jercher, José Diogo Simão and Sebastian Steinhaus
{"title":"( 2 + 1 ) ...","authors":"Alexander F Jercher, José Diogo Simão and Sebastian Steinhaus","doi":"10.1088/1361-6382/adc8f1","DOIUrl":"https://doi.org/10.1088/1361-6382/adc8f1","url":null,"abstract":"We construct an effective cosmological spin-foam model for a dimensional spatially flat Universe, discretized on a cubical lattice, containing both space- and time-like regions. Our starting point is the recently proposed coherent state spin-foam model for (2+1) Lorentzian quantum gravity. The full amplitude is assumed to factorize into single vertex amplitudes with boundary data corresponding to Lorentzian 3-frusta. A stationary phase approximation is performed at each vertex individually, where the inverse square root of the Hessian determinant serves as a measure for the effective path integral. Additionally, a massive scalar field is coupled to the geometry, and we show that its mass renders the partition function convergent. For a single 3-frustum with time-like struts, we compute the expectation value of the bulk strut length and show that it generically agrees with the classical solutions and that it is a discontinuous function of the scalar field mass. Allowing the struts to be space-like introduces causality violations, which drive the expectation values away from the classical solutions due to the lack of an exponential suppression of these configurations. This is a direct consequence of the semi-classical amplitude only containing the real part of deficit angles, in contrast with the Lorentzian Regge action used in effective spin-foams. We give an outlook on how to evaluate the partition function on an extended discretization including a bulk spatial slice. This serves as a foundation for future investigations of physically interesting scenarios such as a quantum bounce or the viability of massive scalar field clocks. Our results demonstrate that the effective path integral in the causally regular sector serves as a viable quantum cosmology model, but that the agreement of expectation values with classical solutions is tightly bound to the path integral measure.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"26 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836933","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}
Mariam Campbell, Sante Carloni, Peter K S Dunsby and Nolene F Naidu
{"title":"Some exact relativistic star solutions in f(R) gravity","authors":"Mariam Campbell, Sante Carloni, Peter K S Dunsby and Nolene F Naidu","doi":"10.1088/1361-6382/adc8f2","DOIUrl":"https://doi.org/10.1088/1361-6382/adc8f2","url":null,"abstract":"We present a covariant description of non-vacuum static spherically symmetric spacetimes in f(R) gravity applying the (1+1+2) covariant formalism. The propagation equations are then used to derive a covariant and dimensionless form of the Tolman–Oppenheimer–Volkoff equations. We then give a solution strategy to these equations and obtain some new exact solutions for the particular case , which have the correct thermodynamic properties for standard matter.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"67 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832355","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":"Unveiling orbital chaos: the wild heart of fuzzy dark matter structures","authors":"Iván Álvarez-Rios and Francisco S Guzmán","doi":"10.1088/1361-6382/adc9f0","DOIUrl":"https://doi.org/10.1088/1361-6382/adc9f0","url":null,"abstract":"In this paper we study the behavior of test particles on top of a galactic-type of fuzzy dark matter (FDM) structure, characterized by the core–halo density profile found in simulations. Our workhorse structure is an anisotropic, time-dependent, virialized core–tail FDM clump resulting from a multicore merger. For our analysis we allow this structure to keep evolving, which implies that the core oscillates and accretes matter from the halo, while the halo dynamics is dominated by its characteristic high kinetic energy. On top of this time-dependent structure that in turn has a time-dependent gravitational potential, we solve the motion equations of test particles with initial conditions associated to circular orbits at different radii. Our results indicate that: (1) no trajectory remains circular, (2) the trajectories are sensitive to initial conditions and (3) the departure of initially near trajectories has always a positive Lyapunov exponent. A qualitative result is that the motion of test particles is more erratic with a bigger Lyapunov exponent within and near the core than in the halo region, which can be understood in terms of the random motion of the core within the core–halo structure. We expect these results warn on the importance of the anisotropic and time-dependent nature of FDM clumps when studying the motion of test particles.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"22 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832356","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}
I P R Baranov, H A Borges, F C Sobrinho and S Carneiro
{"title":"Wormhole solutions in quantum spacetime","authors":"I P R Baranov, H A Borges, F C Sobrinho and S Carneiro","doi":"10.1088/1361-6382/adc86a","DOIUrl":"https://doi.org/10.1088/1361-6382/adc86a","url":null,"abstract":"Polymer models have been used to describe non-singular quantum black holes, where the classical singularity is replaced by a transition from a black hole to a white hole. In a previous letter, in the context of a uni-parametric model with asymptotic flat exterior metric, we fixed the radius of the transition surface through the identification of its area with the area gap of loop quantum gravity. This revealed a dependence of the polymerisation parameter on the black hole mass, where the former increases as the latter decreases. It also enabled the extension of the model to Planck-scale black holes. We have identified the existence of limiting states with masses and zero surface gravity, showing that Hawking evaporation asymptotically leads to remnant black holes of Planck size. In the present paper, we consider solutions with , again observing the presence of a minimal radius, but without formation of horizons. Unlike the previous mass range, only charged solutions are allowed in this case. We show that these non-singular solutions can be extended to static wormholes with a throat at the minimal radius, traversable by null geodesics and by test particles with high enough kinetic energy.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"40 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827711","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}
Piotr T Chruściel, Wan Cong, Théophile Quéau and Raphaela Wutte
{"title":"Cauchy problems for Einstein equations in three-dimensional spacetimes","authors":"Piotr T Chruściel, Wan Cong, Théophile Quéau and Raphaela Wutte","doi":"10.1088/1361-6382/adc4b7","DOIUrl":"https://doi.org/10.1088/1361-6382/adc4b7","url":null,"abstract":"We analyze existence and properties of solutions of two-dimensional general relativistic initial data sets with a negative cosmological constant, both on spacelike and characteristic surfaces. A new family of such vacuum spacelike data parameterised by poles at the conformal boundary at infinity is constructed. We review the notions of global Hamiltonian charges, emphasizing the difficulties arising in this dimension, both in a spacelike and characteristic setting. One or two, depending upon the topology, lower bounds for energy in terms of angular momentum, linear momentum, and center of mass are established.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"4 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143819443","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":"Renormalisation in maximally symmetric spaces and semiclassical gravity in Anti-de Sitter spacetime","authors":"Benito A Juárez-Aubry and Milton C Mamani-Leqque","doi":"10.1088/1361-6382/adc535","DOIUrl":"https://doi.org/10.1088/1361-6382/adc535","url":null,"abstract":"We obtain semiclassical gravity solutions in the Poincaré fundamental domain of -dimensional Anti-de Sitter spacetime, PAdS4, with a (massive or massless) Klein–Gordon field (with possibly non-trivial curvature coupling) with Dirichlet or Neumann boundary. Some results are explicitly and graphically presented for special values of the mass and curvature coupling (e.g. minimal or conformal coupling). In order to achieve this, we study in some generality how to perform the Hadamard renormalisation procedure for non-linear observables in maximally symmetric spacetimes in arbitrary dimensions, with emphasis on the stress-energy tensor. We show that, in this maximally symmetric setting, the Hadamard bi-distribution is invariant under the isometries of the spacetime, and can be seen as a ‘single-argument’ distribution depending only on the geodesic distance, which significantly simplifies the Hadamard recursion relations and renormalisation computations.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"108 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143819728","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":"Symmetry-reduced loop quantum gravity: plane waves, flat space and the Hamiltonian constraint","authors":"F Hinterleitner","doi":"10.1088/1361-6382/adc5d4","DOIUrl":"https://doi.org/10.1088/1361-6382/adc5d4","url":null,"abstract":"Loop quantum gravity (LQG) methods are applied to a symmetry-reduced model with homogeneity in two dimensions, derived from a Gowdy model. The conditions for the propagation of unidirectional plane gravitational waves at exactly the speed of light are set up in the form of two null Killing equations in terms of Ashtekar variables and imposed as operators on the quantum states of the system. Owing to symmetry reduction the gauge group of the system reduces formally from SU(2) to U(1). Under the assumption of equal spacing of the holonomy eigenvalues, the solutions are not normalizable in the sense of the usual inner product on U(1). Taking over the inner product from the genuine gauge group SU(2) of LQG renders the obtained states normalizable, nevertheless fluctuations of geometrical quantities remain divergent. In consequence, the solutions of the (non-commuting) Killing conditions have to be renormalized. Two kinds of renormalization are presented. The combination of the occurrence of non-commuting Killing operators and the necessity of renormalization indicates fluctuations of the propagation speed, i. e. dispersion of gravitational waves. Finally the same methods are applied to the Hamiltonian constraint with the same result concerning normalizability. After renormalization the constraint is not exactly satisfied any more, which suggests the presence of some kind of interacting matter.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"74 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143819734","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}
Lang Ding, Qingbin Luo, Yi Lv, Yuanmeng Zheng, Haoyu Liao and Zhuoyan Chen
{"title":"Quantum circuit implementation and security analysis of IVLBC","authors":"Lang Ding, Qingbin Luo, Yi Lv, Yuanmeng Zheng, Haoyu Liao and Zhuoyan Chen","doi":"10.1088/1361-6382/adc6eb","DOIUrl":"https://doi.org/10.1088/1361-6382/adc6eb","url":null,"abstract":"Grover’s algorithm reduces the security level of the target cipher from n-bit to n/2-bit. To implement Grover’s algorithm, a quantum circuit capable of performing the target cipher operations must be constructed. In this paper, we propose a quantum circuit implementation scheme for the involutive lightweight block cipher (IVLBC) block cipher. We utilized the DORCIS tool to implement the quantum circuit for the S-box and applied Gaussian elimination to construct the quantum circuit for matrix multiplication. Subsequently, we evaluated the overall quantum resource consumption required for the implementation. Based on this, we performed a quantum attack on IVLBC using Grover’s algorithm, calculating the attack cost using the NCT gate library, and further analyzed its security. Finally, we conducted a comparative analysis of the classical attack complexity and quantum attack complexity of IVLBC, highlighting the potential of using quantum complexity as a standard for future security assessments.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805864","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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