Classical and Quantum Gravity最新文献

{"title":"Binary neutron star mergers using a discontinuous Galerkin-finite difference hybrid method","authors":"Nils Deppe, Francois Foucart, Marceline S Bonilla, Michael Boyle, Nicholas J Corso, Matthew D Duez, Matthew Giesler, François Hébert, Lawrence E Kidder, Yoonsoo Kim, Prayush Kumar, Isaac Legred, Geoffrey Lovelace, Elias R Most, Jordan Moxon, Kyle C Nelli, Harald P Pfeiffer, Mark A Scheel, Saul A Teukolsky, William Throwe and Nils L Vu","doi":"10.1088/1361-6382/ad88cf","DOIUrl":"https://doi.org/10.1088/1361-6382/ad88cf","url":null,"abstract":"We present a discontinuous Galerkin-finite difference hybrid scheme that allows high-order shock capturing with the discontinuous Galerkin method for general relativistic magnetohydrodynamics in dynamical spacetimes. We present several optimizations and stability improvements to our algorithm that allow the hybrid method to successfully simulate single, rotating, and binary neutron stars. The hybrid method achieves the efficiency of discontinuous Galerkin methods throughout almost the entire spacetime during the inspiral phase, while being able to robustly capture shocks and resolve the stellar surfaces. We also use Cauchy-characteristic evolution to compute the first gravitational waveforms at future null infinity from binary neutron star mergers. The simulations presented here are the first successful binary neutron star inspiral and merger simulations using discontinuous Galerkin methods.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"153 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598036","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":"Characterizing gravitational wave detector networks: from A ♯ to cosmic explorer","authors":"Ish Gupta, Chaitanya Afle, K G Arun, Ananya Bandopadhyay, Masha Baryakhtar, Sylvia Biscoveanu, Ssohrab Borhanian, Floor Broekgaarden, Alessandra Corsi, Arnab Dhani, Matthew Evans, Evan D Hall, Otto A Hannuksela, Keisi Kacanja, Rahul Kashyap, Sanika Khadkikar, Kevin Kuns, Tjonnie G F Li, Andrew L Miller, Alexander Harvey Nitz, Benjamin J Owen, Cristiano Palomba, Anthony Pearce, Hemantakumar Phurailatpam, Binod Rajbhandari, Jocelyn Read, Joseph D Romano, Bangalore S Sathyaprakash, David H Shoemaker, Divya Singh, Salvatore Vitale, Lisa Barsotti, Emanuele Berti, Craig Cahillane, Hsin-Yu Chen, Peter Fritschel, Carl-Johan Haster, Philippe Landry, Geoffrey Lovelace, David McClelland, Bram J J Slagmolen, Joshua R Smith, Marcelle Soares-Santos, Ling Sun, David Tanner, Hiro Yamamoto, Michael Zucker","doi":"10.1088/1361-6382/ad7b99","DOIUrl":"https://doi.org/10.1088/1361-6382/ad7b99","url":null,"abstract":"Gravitational-wave observations by the laser interferometer gravitational-wave observatory (LIGO) and Virgo have provided us a new tool to explore the Universe on all scales from nuclear physics to the cosmos and have the massive potential to further impact fundamental physics, astrophysics, and cosmology for decades to come. In this paper we have studied the science capabilities of a network of LIGO detectors when they reach their best possible sensitivity, called A<inline-formula>\u0000<tex-math><?CDATA $^sharp$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mo>♯</mml:mo></mml:msup></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"cqgad7b99ieqn2.gif\"></inline-graphic></inline-formula>, given the infrastructure in which they exist and a new generation of observatories that are factor of 10 to 100 times more sensitive (depending on the frequency), in particular a pair of L-shaped cosmic explorer (CE) observatories (one 40 km and one 20 km arm length) in the US and the triangular Einstein telescope with 10 km arms in Europe. We use a set of science metrics derived from the top priorities of several funding agencies to characterize the science capabilities of different networks. The presence of one or two A<inline-formula>\u0000<tex-math><?CDATA $^sharp$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mo>♯</mml:mo></mml:msup></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"cqgad7b99ieqn3.gif\"></inline-graphic></inline-formula> observatories in a network containing two or one next generation observatories, respectively, will provide good localization capabilities for facilitating multimessenger astronomy (MMA) and precision measurement of the Hubble parameter. Two CE observatories are indispensable for achieving precise localization of binary neutron star events, facilitating detection of electromagnetic counterparts and transforming MMA. Their combined operation is even more important in the detection and localization of high-redshift sources, such as binary neutron stars, beyond the star-formation peak, and primordial black hole mergers, which may occur roughly 100 million years after the Big Bang. The addition of the Einstein Telescope to a network of two CE observatories is critical for accomplishing all the identified science metrics including the nuclear equation of state, cosmological parameters, the growth of black holes through cosmic history, but also make new discoveries such as the presence of dark matter within or around neutron stars and black holes, continuous gravitational waves from rotating neutron stars, transient signals from supernovae, and the production of stellar-mass black holes in the early Universe. For most metrics the triple network of next generation terrestrial observatories are a factor 100 better than what can be accomplished by a network of three A<inline-formula>\u0000<tex-math><?CDATA $^sharp$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:ms","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"38 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597277","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":"Towards the solution of coating loss measurements using thermoelastic-dominated substrates","authors":"L Silenzi, F Fabrizi, M Granata, L Mereni, M Montani, F Piergiovanni, A Trapananti, F Travasso and G Cagnoli","doi":"10.1088/1361-6382/ad8543","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8543","url":null,"abstract":"The characterization of thin film parameters derives from the measurement difference between the coated and bare substrate. This method of comparison is based on the stationarity of the substrate: the characteristics of the substrate do not depend on the presence of the film. However, the thermoelastic loss of a coated substrate depends on the thermo-mechanical parameters of the film as well, which are generally unknown. When thermoelastic loss is dominant, the coating loss measurements are completely altered. In this paper, we propose a model that helps to understand the role of each material property in the thermoelasticity of layered plates, and with this we identified three possible cases in which any coating-substrate combination could be classified. In particular, we analyzed the IBS silica film deposited on silicon. Using the model, we were able to explain the experimental results and also selected a thinner substrate for future coating loss measurements. With this choice, cryogenic loss measurements on bare substrate confirm that thermoelastic loss becomes irrelevant for temperatures below 130 K–180 K, depending on the mode.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"13 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594643","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":"Dynamical system analysis in modified Galileon cosmology","authors":"L K Duchaniya, B Mishra, I V Fomin and S V Chervon","doi":"10.1088/1361-6382/ad8a13","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8a13","url":null,"abstract":"In this paper, we have investigated the phase space analysis in modified Galileon cosmology, where the Galileon term is considered a coupled scalar field, . We focus on the exponential type function of and the three well-motivated potential functions . We obtain the critical points of the autonomous system, along with their stability conditions and cosmological properties. The critical points of the autonomous system describe different phases of the Universe. The scaling solution for critical points was found in our analysis to determine the matter-dark energy and radiation-dark energy-dominated eras of the Universe. In these scaling solutions, dark energy is typically introduced alongside another component, such as radiation or matter, and helps explain the transition between cosmological eras. The dark energy dominated critical points show stable behavior and indicate the late-time cosmic acceleration phase of the Universe. Further, the results are examined with the Hubble rate H(z) and the Supernovae Ia cosmological data sets.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"95 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594644","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":"On the convergence of cosmographic expansions in Lemaître–Tolman–Bondi models","authors":"Asha B Modan and S M Koksbang","doi":"10.1088/1361-6382/ad8abc","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8abc","url":null,"abstract":"We study cosmographic expansions of the luminosity distance for a variety of Lemaître–Tolman–Bondi (LTB) models which we specify inspired by local large-scale structures of the Universe. We consider cosmographic expansions valid for general spacetimes and compare to the Friedmann–Lemaître–Robertson–Walker (FLRW) limit of the expansions as well as to its naive isotropic extrapolation to an inhomogeneous Universe. The FLRW expansions are often poor near the observer but become better at higher redshifts, where the light rays have reached the FLRW background. In line with this we find that the effective Hubble, deceleration and jerk parameters of the general cosmographic expansion are often very different from the global ΛCDM values, with deviations up to several orders of magnitude. By comparing with the naive isotropic extrapolation of the FLRW expansion, we assess that these large deviations are mainly due to gradients of the shear. Very close to the observer, the general cosmographic expansion is always best and becomes more precise when more expansion terms are included. However, we find that the convergence radius of the general cosmographic expansion is small for all studied models and observers and the general cosmographic expansion becomes poor for most of the studied observers already before a single LTB structure has been traversed. The small radius of convergence of the general cosmographic expansion has also been indicated by earlier work and may need careful attention before we can safely apply the general cosmographic expansion to real data.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"18 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594646","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":"The model of the local Universe in the framework of the second-order perturbation theory","authors":"Szymon Sikora and Jan J Ostrowski","doi":"10.1088/1361-6382/ad8a10","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8a10","url":null,"abstract":"Recently, we constructed the specific solution to the second-order cosmological perturbation theory, around any Friedmann–Lemaître–Robertson–Walker background filled with dust matter and a positive cosmological constant. In this paper, we use the Cosmicflows-4 sample of galaxies from the Extragalactic Distance Database to constrain this metric tensor. We obtain an approximation to the local matter distribution and geometry. We numerically solve for null geodesics for randomly distributed mock sources and compare this model with the Lemaître–Hubble constant inferred from the observations under the assumption of perfect isotropy and homogeneity. We conclude on effects of realistic inhomogeneities on the luminosity distance in the context of the Hubble tension and discuss limitations of our approach.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"68 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588505","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":"The pseudospectrum and transient of Kaluza–Klein black holes in Einstein–Gauss–Bonnet gravity","authors":"Jia-Ning Chen, Liang-Bi Wu and Zong-Kuan Guo","doi":"10.1088/1361-6382/ad89a1","DOIUrl":"https://doi.org/10.1088/1361-6382/ad89a1","url":null,"abstract":"The spectrum and dynamical instability, as well as the transient effect of the tensor perturbation for the so-called Maeda–Dadhich black hole, a type of Kaluza–Klein black hole, in Einstein–Gauss–Bonnet gravity have been investigated in framework of pseudospectrum. We cast the problem of solving quasinormal modes (QNMs) in AdS-like spacetime as the linear evolution problem of the non-normal operator in null slicing by using ingoing Eddington–Finkelstein coordinates. In terms of spectrum instability, based on the generalized eigenvalue problem, the QNM spectrum and ε-pseudospectrum has been studied, while the open structure of ε-pseudospectrum caused by the non-normality of operator indicates the spectrum instability. In terms of dynamical instability, we introduce the concept of the distance to dynamical instability, which plays a crucial role in bridging the spectrum instability and the dynamical instability. We calculate such distance, named the complex stability radius, as parameters vary. Finally, we show the behavior of the energy norm of the evolution operator, which can be roughly reflected by the three kinds of abscissas in context of pseudospectrum, and find the transient growth of the energy norm of the evolution operator.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"38 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588535","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":"Dynamical friction in rotating ultralight dark matter galactic cores","authors":"V M Gorkavenko, O V Barabash, T V Gorkavenko, O M Teslyk, A O Zaporozhchenko, Junji Jia, A I Yakimenko and E V Gorbar","doi":"10.1088/1361-6382/ad8a11","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8a11","url":null,"abstract":"Dynamical friction and stellar orbital motion in spiral galaxies with dark matter composed of ultralight bosons in the state of rotating Bose–Einstein condensate (BEC) are studied. It is found that the dynamical friction force is significantly affected by the topological charge of the vortex structure of the BEC core with the strongest effect at distances near the galactic center. It is also shown that the ultralight dark matter self-interaction plays an important role in studying the dynamical friction.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"146 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588500","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":"Gauge invariant perturbations of static spatially compact LRS II spacetimes","authors":"Paulo Luz and Sante Carloni","doi":"10.1088/1361-6382/ad8a14","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8a14","url":null,"abstract":"We present a framework to describe completely general first-order perturbations of static, spatially compact, and locally rotationally symmetric class II spacetimes within the theory of general relativity. The perturbation variables are by construction covariant and identification gauge invariant and encompass the geometry and the thermodynamics of the fluid sources. The new equations are then applied to the study of isotropic, adiabatic perturbations. We discuss how the choice of frame in which perturbations are described can significantly simplify the mathematical analysis of the problem and show that it is possible to change frames directly from the linear level equations. We find explicitly that the case of isotropic, adiabatic perturbations can be reduced to a singular Sturm–Liouville eigenvalue problem, and lower bounds for the values of the eigenfrequencies can be derived. These results lay the theoretical groundwork to analytically describe linear, isotropic, and adiabatic perturbations of static, spherically symmetric spacetimes.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"8 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588501","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":"The universal thermodynamic properties of extremely compact objects","authors":"Samir D Mathur and Madhur Mehta","doi":"10.1088/1361-6382/ad869e","DOIUrl":"https://doi.org/10.1088/1361-6382/ad869e","url":null,"abstract":"An extremely compact object (ECO) is defined as a quantum object without horizon, whose radius is just a small distance s outside its Schwarzschild radius. We show that any ECO of mass M in d + 1 dimensions with must have (at leading order) the same thermodynamic properties—temperature, entropy and radiation rates—as the corresponding semiclassical black hole of mass M. An essential aspect of the argument involves showing that the Tolman–Oppenheimer–Volkoff equation has no consistent solution in the region just outside the ECO surface, unless this region is filled with radiation at the (appropriately blueshifted) Hawking temperature. In string theory it has been found that black hole microstates are fuzzballs—objects with no horizon—which are expected to have a radius that is only a little larger than the horizon radius. Thus the arguments of this paper provide a nice closure to the fuzzball paradigm: the absence of a horizon removes the information paradox, and the thermodynamic properties of the semiclassical hole are nonetheless recovered to an excellent approximation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"242 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579929","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}