arXiv: General Relativity and Quantum Cosmology最新文献_第4页

Path integral renormalization in loop quantum cosmology 环量子宇宙学中的路径积分重整化

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-12-03 DOI: 10.1103/PhysRevD.103.126021

N. Bodendorfer, Muxin Han, Fabian Haneder, Hongguang Liu

{"title":"Path integral renormalization in loop quantum cosmology","authors":"N. Bodendorfer, Muxin Han, Fabian Haneder, Hongguang Liu","doi":"10.1103/PhysRevD.103.126021","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.126021","url":null,"abstract":"A coarse graining technique akin to block spin transformations that groups together fiducial cells in a homogeneous and isotropic universe has been recently developed in the context of loop quantum cosmology. The key technical ingredient was an SU(1, 1) group and Lie algebra structure of the physical observables as well as the use of Perelomov coherent states for SU(1, 1). It was shown that the coarse graining operation is completely captured by changing group representations. Based on this result, it was subsequently shown that one can extract an explicit renormalisation group flow of the loop quantum cosmology Hamiltonian operator in a simple model with dust-clock. In this paper, we continue this line of investigation and derive a coherent state path integral formulation of this quantum theory and extract an explicit expression for the renormalisation-scale dependent classical Hamiltonian entering the path integral for a coarse grained description at that scale. We find corrections to the non-renormalised Hamiltonian that are qualitatively similar to those previously investigated via canonical quantisation. In particular, they are again most sensitive to small quantum numbers, showing that the large quantum number (spin) description captured by so called \"effective equations\" in loop quantum cosmology does not reproduce the physics of many small quantum numbers (spins). Our results have direct impact on path integral quantisation in loop quantum gravity, showing that the usually taken large spin limit should be expected not to capture (without renormalisation, as mostly done) the physics of many small spins that is usually assumed to be present in physically reasonable quantum states.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79373152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

New effective precession spin for modeling multimodal gravitational waveforms in the strong-field regime 模拟强场下多模态引力波的新有效旋进

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-12-03 DOI: 10.1103/PHYSREVD.103.083022

L. Thomas, P. Schmidt, G. Pratten

{"title":"New effective precession spin for modeling multimodal gravitational waveforms in the strong-field regime","authors":"L. Thomas, P. Schmidt, G. Pratten","doi":"10.1103/PHYSREVD.103.083022","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.083022","url":null,"abstract":"Accurately modelling the complete gravitational-wave signal from precessing binary black holes through the late inspiral, merger and ringdown remains a challenging problem. The lack of analytic solutions for the precession dynamics of generic double-spin systems, and the high dimensionality of the problem, obfuscate the incorporation of strong-field spin-precession information into semi-analytic waveform models used in gravitational-wave data analysis. Previously, an effective precession spin, $chi_p$, was introduced to reduce the number of spin degrees of freedom. Here, we show that $chi_p$ alone does not accurately reproduce higher-order multipolar modes, in particular the ones that carry strong imprints due to precession such as the $(2,1)$-mode. To improve the higher-mode content, and in particular to facilitate an accurate incorporation of precession effects in the strong-field regime into waveform models, we introduce a new dimensional reduction through an effective precession spin vector, $vec{chi}_perp$, which takes into account precessing spin information from both black holes. We show that this adapted effective precession spin (i) mimics the precession dynamics of the fully precessing configuration remarkably well, (ii) captures the signature features of precession in higher-order modes, and (iii) reproduces the final state of the remnant black hole with high accuracy for the overwhelming majority of configurations. We demonstrate the efficacy of this two-dimensional precession spin in the strong-field regime, paving the path for meaningful calibration of the precessing sector of semi-analytic waveform models with a faithful representation of higher-order modes through merger and the remnant black hole spin.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90952126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Scalarized Einstein-Born-Infeld black holes 缩放爱因斯坦-因菲尔德黑洞

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-12-02 DOI: 10.1103/PhysRevD.103.104012

Peng Wang, Houwen Wu, Haitang Yang

{"title":"Scalarized Einstein-Born-Infeld black holes","authors":"Peng Wang, Houwen Wu, Haitang Yang","doi":"10.1103/PhysRevD.103.104012","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.104012","url":null,"abstract":"The phenomenon of spontaneous scalarization of Reissner-Nordstr\"{o}m (RN) black holes has recently been found in an Einstein-Maxwell-scalar (EMS) model due to a non-minimal coupling between the scalar and Maxwell fields. Non-linear electrodynamics, e.g., Born-Infeld (BI) electrodynamics, generalizes Maxwell's theory in the strong field regime. Non-minimally coupling the BI field to the scalar field, we study spontaneous scalarization of an Einstein-Born-Infeld-scalar (EBIS) model in this paper. It shows that there are two types of scalarized black hole solutions, i.e., scalarized RN-like and Schwarzschild-like solutions. Although the behavior of scalarized RN-like solutions in the EBIS model is quite similar to that of scalarize solutions in the EMS model, we find that there exist significant differences between scalarized Schwarzschild-like solutions in the EBIS model and scalarized solutions in the EMS model. In particular, the domain of existence of scalarized Schwarzschild-like solutions possesses a certain region, which is composed of two branches. The branch of larger horizon area is a family of disconnected scalarized solutions, which do not bifurcate from scalar-free black holes. However, the branch of smaller horizon area may or may not bifurcate from scalar-free black holes depending on the parameters. Additionally, these two branches of scalarized solutions can be both entropically disfavored over comparable scalar-free black holes in some parameter region.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83721414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Compact objects in entangled relativity 纠缠相对论中的紧致物体

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-30 DOI: 10.1103/PHYSREVD.103.024034

Denis Arruga, O. Rousselle, O. Minazzoli

引用次数: 6

Perturbations of the almost Killing equation and their implications 近似杀戮方程的微扰及其意义

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-27 DOI: 10.1103/PHYSREVD.103.084020

S. Chakraborty, Justin C. Feng

引用次数: 1

Bonnor-Vaidya charged point mass in an external Maxwell field 外部麦克斯韦场中的Bonnor-Vaidya带电质点

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-27 DOI: 10.1103/PHYSREVD.103.044039

P. A. Hogan, D. Puetzfeld

引用次数: 0

Reliability of parameter estimates in the first observing run of Advanced LIGO 先进LIGO首次观测运行中参数估计的可靠性

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-27 DOI: 10.1103/PHYSREVD.103.104002

S. Kulkarni, C. Capano

{"title":"Reliability of parameter estimates in the first observing run of Advanced LIGO","authors":"S. Kulkarni, C. Capano","doi":"10.1103/PHYSREVD.103.104002","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.104002","url":null,"abstract":"Accurate parameter estimation is key to maximizing the scientific impact of gravitational-wave astronomy. Parameters of a binary merger are typically estimated using Bayesian inference. It is necessary to make several assumptions when doing so, one of which is that the the detectors output stationary Gaussian noise. We test the validity of these assumptions by performing percentile-percentile tests in both simulated Gaussian noise and real detector data in the first observing run of Advanced LIGO (O1). We add simulated signals to 512s of data centered on each of the three events detected in O1 -- GW150914, GW151012, and GW151226 -- and check that the recovered credible intervals match statistical expectations. We find that we are able to recover unbiased parameter estimates in the real detector data, indicating that the assumption of Gaussian noise does not adversely effect parameter estimates. However, we also find that both the parallel-tempered emcee sampler emcee_pt and the nested sampler dynesty struggle to produced unbiased parameter estimates for GW151226-like signals, even in simulated Gaussian noise. The emcee_pt sampler does produce unbiased estimates for GW150914-like signals. This highlights the importance of performing percentile-percentile tests in different targeted areas of parameter space.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85567173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Use of an excess power method and a convolutional neural network in an all-sky search for continuous gravitational waves 使用超功率法和卷积神经网络在全天搜索连续引力波

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-25 DOI: 10.1103/physrevd.103.084049

Takahiro Yamamoto, Takahiro Tanaka

{"title":"Use of an excess power method and a convolutional neural network in an all-sky search for continuous gravitational waves","authors":"Takahiro Yamamoto, Takahiro Tanaka","doi":"10.1103/physrevd.103.084049","DOIUrl":"https://doi.org/10.1103/physrevd.103.084049","url":null,"abstract":"The signal of continuous gravitational waves has a longer duration than the observation period. Even if the waveform in the source frame is monochromatic, we will observe the waveform with modulated frequencies due to the motion of the detector. If the source location is unknown, a lot of templates having different sky positions are required to demodulate the frequency and the required large computational cost restricts the applicable parameter region of coherent search. In this work, we propose and examine a new method to select candidates, which reduces the cost of coherent search by following-up only the selected candidates. As a first step, we consider a slightly idealized situation in which only a single-detector having 100% duty cycle is available and its detector noise is approximated by the stationary Gaussian noise. We combine several methods: 1) the short-time Fourier transform with the re-sampled data such that the Earth motion for the source is canceled in some reference direction, 2) the excess power search in the Fourier transform of the time series obtained by picking up the amplitude in a particular frequency bin from the short-time Fourier transform data, and 3) the deep learning method to further constrain the source sky position. We compare the computational cost and the minimum amplitude of the detectable signal with the coherent matched filtering analysis. With a reasonable computational cost, we find that our method can detect the signal having only 32% larger amplitude than that of the coherent search with 95% detection efficiency.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75433526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Brans-Dicke analogue of the Roberts geometry 罗伯茨几何的Brans-Dicke类比

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-24 DOI: 10.1103/PHYSREVD.103.084004

Bardia H. Fahim, V. Faraoni, A. Giusti

引用次数: 1

Growth of perturbations using Lambert W equation of state 利用Lambert W状态方程的微扰生长

arXiv: General Relativity and Quantum Cosmology Pub Date : 2020-11-24 DOI: 10.1142/S0219887821501395

Manisha Banerjee, Sudipta Das, Abdulla Al Mamon, S. Saha, K. Bamba

引用次数: 2