Pub Date : 2024-12-12DOI: 10.1088/1361-6382/ad942f
Sergiu I Vacaru
Nonassociative modifications of general relativity, GR, and quantum gravity, QG, models naturally arise as star product and R-flux deformations considered in string/M-theory. Such nonassociative and noncommutative geometric and quantum information theories were formulated on phase spaces defined as cotangent Lorentz bundles enabled with nonassociative symmetric and nonsymmetric metrics and nonlinear and linear connection structures. We outline the analytic methods and proofs that corresponding geometric flow evolution and dynamical field equations can be decoupled and integrated in certain general off-diagonal forms. New classes of solutions describing nonassociative black holes, wormholes, and locally anisotropic cosmological configurations are constructed using such methods. We develop the Batalin–Vilkovisky, BV, formalism for quantizing modified gravity theories, MGTs, involving twisted star products and semi-classical models of nonassociative gauge gravity with de Sitter/affine/ Poincaré double structure groups. Such theories can be projected on Lorentz spacetime manifolds in certain forms equivalent to GR or MGTs with torsion generalizations etc. We study the properties of the classical and quantum BV operators for nonassociative phase spaces and nonassociative gauge gravity. Recent results and methods from algebraic QFT are generalized to involve nonassociative star product deformations of the anomalous master Ward identity. Such constructions are elaborated in a nonassociative BV perspective and for developing non-perturbative methods in QG.
{"title":"Nonassociative gauge gravity theories with R-flux star products and Batalin–Vilkovisky quantization in algebraic quantum field theory","authors":"Sergiu I Vacaru","doi":"10.1088/1361-6382/ad942f","DOIUrl":"https://doi.org/10.1088/1361-6382/ad942f","url":null,"abstract":"Nonassociative modifications of general relativity, GR, and quantum gravity, QG, models naturally arise as star product and R-flux deformations considered in string/M-theory. Such nonassociative and noncommutative geometric and quantum information theories were formulated on phase spaces defined as cotangent Lorentz bundles enabled with nonassociative symmetric and nonsymmetric metrics and nonlinear and linear connection structures. We outline the analytic methods and proofs that corresponding geometric flow evolution and dynamical field equations can be decoupled and integrated in certain general off-diagonal forms. New classes of solutions describing nonassociative black holes, wormholes, and locally anisotropic cosmological configurations are constructed using such methods. We develop the Batalin–Vilkovisky, BV, formalism for quantizing modified gravity theories, MGTs, involving twisted star products and semi-classical models of nonassociative gauge gravity with de Sitter/affine/ Poincaré double structure groups. Such theories can be projected on Lorentz spacetime manifolds in certain forms equivalent to GR or MGTs with torsion generalizations etc. We study the properties of the classical and quantum BV operators for nonassociative phase spaces and nonassociative gauge gravity. Recent results and methods from algebraic QFT are generalized to involve nonassociative star product deformations of the anomalous master Ward identity. Such constructions are elaborated in a nonassociative BV perspective and for developing non-perturbative methods in QG.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"39 9 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809486","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}
Pub Date : 2024-12-12DOI: 10.1088/1361-6382/ad98e0
Carlos F S Pereira, Denis C Rodrigues, Ébano L Martins, Júlio C Fabris and Manuel E Rodrigues
In the present study, we generalize the possible ghost field configurations within the framework of k-essence theory to the Simpson–Visser metric area function . Our analysis encompasses field configurations for the region-defined metric function as well as the general solution that asymptotically behaves as Schwarzschild-de Sitter for . Specifically, we investigate two scalar field configurations and define the associated potential for each one. Through rigorous calculations, we verify that all equations of motion are satisfied. Notably, our findings indicate that even when proposing new configurations of ghost scalar fields, the energy conditions remain unchanged. This result serves to validate the wormhole solutions obtained in previous studies.
{"title":"New sources of ghost fields in k-essence theories for black-bounce solutions","authors":"Carlos F S Pereira, Denis C Rodrigues, Ébano L Martins, Júlio C Fabris and Manuel E Rodrigues","doi":"10.1088/1361-6382/ad98e0","DOIUrl":"https://doi.org/10.1088/1361-6382/ad98e0","url":null,"abstract":"In the present study, we generalize the possible ghost field configurations within the framework of k-essence theory to the Simpson–Visser metric area function . Our analysis encompasses field configurations for the region-defined metric function as well as the general solution that asymptotically behaves as Schwarzschild-de Sitter for . Specifically, we investigate two scalar field configurations and define the associated potential for each one. Through rigorous calculations, we verify that all equations of motion are satisfied. Notably, our findings indicate that even when proposing new configurations of ghost scalar fields, the energy conditions remain unchanged. This result serves to validate the wormhole solutions obtained in previous studies.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"27 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809491","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}
Pub Date : 2024-12-12DOI: 10.1088/1361-6382/ad92d8
Hidetomo Hoshino, Takuya Tsuchiya and Gen Yoneda
In this study, we investigate the numerical stability of the covariant Baumgarte–Shapiro–Shibata–Nakamura (cBSSN) formulation against the Friedmann–Lemaitre–Robertson–Walker spacetime. To evaluate the numerical stability, we calculate the constraint amplification factor by the eigenvalue analysis of the evolution of the constraint. We propose a modification to the time evolution equations of the cBSSN formulation for higher numerical stability. Furthermore, we perform numerical simulations using the modified formulation to confirm its improved stability.
{"title":"Stability analysis and improvement of the covariant BSSN formulation against the FLRW spacetime background","authors":"Hidetomo Hoshino, Takuya Tsuchiya and Gen Yoneda","doi":"10.1088/1361-6382/ad92d8","DOIUrl":"https://doi.org/10.1088/1361-6382/ad92d8","url":null,"abstract":"In this study, we investigate the numerical stability of the covariant Baumgarte–Shapiro–Shibata–Nakamura (cBSSN) formulation against the Friedmann–Lemaitre–Robertson–Walker spacetime. To evaluate the numerical stability, we calculate the constraint amplification factor by the eigenvalue analysis of the evolution of the constraint. We propose a modification to the time evolution equations of the cBSSN formulation for higher numerical stability. Furthermore, we perform numerical simulations using the modified formulation to confirm its improved stability.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"45 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809440","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}
Pub Date : 2024-11-27DOI: 10.1088/1361-6382/ad922e
Roberto A Sussman and Sebastián Nájera
We propose a new phenomenological second order gravity theory to be denoted as ‘Schouten–Codazzi’ Gravity’ (SCG), as it is based on Schouten and Codazzi tensors. The theory is related, but is clearly distinct from Cotton gravity. By assuming as source the energy momentum of General Relativity, we form a second order system with its geometric sector given by the sum of the Schouten tensor and a generic second order symmetric tensor complying with the following properties: (i) it must satisfy the Codazzi differential condition and (ii) it must be concomitant with the invariant characterization based on the algebraic structure of curvature tensors for specific spacetimes or classes of spacetimes. We derive and briefly discuss the properties of SCG solutions for static spherical symmetry (vacuum and perfect fluid), FLRW models and spherical dust fluids. While we do recognize that SCG is ‘work in progress’ in an incipient stage that still requires significant theoretical development, we believe that the theory provides valuable guidelines in the search for alternatives to General Relativity.
{"title":"Schouten–Codazzi gravity","authors":"Roberto A Sussman and Sebastián Nájera","doi":"10.1088/1361-6382/ad922e","DOIUrl":"https://doi.org/10.1088/1361-6382/ad922e","url":null,"abstract":"We propose a new phenomenological second order gravity theory to be denoted as ‘Schouten–Codazzi’ Gravity’ (SCG), as it is based on Schouten and Codazzi tensors. The theory is related, but is clearly distinct from Cotton gravity. By assuming as source the energy momentum of General Relativity, we form a second order system with its geometric sector given by the sum of the Schouten tensor and a generic second order symmetric tensor complying with the following properties: (i) it must satisfy the Codazzi differential condition and (ii) it must be concomitant with the invariant characterization based on the algebraic structure of curvature tensors for specific spacetimes or classes of spacetimes. We derive and briefly discuss the properties of SCG solutions for static spherical symmetry (vacuum and perfect fluid), FLRW models and spherical dust fluids. While we do recognize that SCG is ‘work in progress’ in an incipient stage that still requires significant theoretical development, we believe that the theory provides valuable guidelines in the search for alternatives to General Relativity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718428","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}
Pub Date : 2024-11-25DOI: 10.1088/1361-6382/ad9132
Xinyu Gong and Changhua Wei
The validity of the cosmic no-hair theorem for polytropic perfect fluids has been established by (Brauer et al 1994 Class. Quantum Grav. 11 2283) within the context of Newtonian cosmology, specifically under conditions of exponential expansion. This paper extends the investigation to assess the nonlinear stability of homogeneous Newtonian cosmological models under general accelerated expansion for perfect fluids. With appropriate assumptions regarding the expansion rate and decay properties of the homogeneous solution, our results demonstrate that the Euler–Poisson system admits a globally classical solution for initial data that are small perturbations to the homogeneous solution. Additionally, we establish that the solution asymptotically approaches the homogeneous solution as time tends to infinity. The theoretical framework is then applied to various types of perfect fluids, including isothermal gases, Chaplygin gases, and polytropic gases.
在牛顿宇宙学的背景下，特别是在指数膨胀的条件下，布劳尔等人 (Brauer et al 1994 Class. Quantum Grav. 11 2283) 确立了多向性完美流体的宇宙无毛定理的有效性。本文扩展了这一研究，以评估完全流体在一般加速膨胀条件下均质牛顿宇宙学模型的非线性稳定性。在对同质解的膨胀率和衰变特性做出适当假设的情况下，我们的结果表明，对于同质解的小扰动初始数据，欧拉-泊松系统具有全局经典解。此外，我们还确定，随着时间趋于无穷大，该解会渐近地接近同质解。理论框架随后被应用于各种类型的完全流体，包括等温气体、查普利金气体和多向气体。
{"title":"Stabilizing effect of the spacetime expansion on the Euler–Poisson equations in Newtonian cosmology","authors":"Xinyu Gong and Changhua Wei","doi":"10.1088/1361-6382/ad9132","DOIUrl":"https://doi.org/10.1088/1361-6382/ad9132","url":null,"abstract":"The validity of the cosmic no-hair theorem for polytropic perfect fluids has been established by (Brauer et al 1994 Class. Quantum Grav. 11 2283) within the context of Newtonian cosmology, specifically under conditions of exponential expansion. This paper extends the investigation to assess the nonlinear stability of homogeneous Newtonian cosmological models under general accelerated expansion for perfect fluids. With appropriate assumptions regarding the expansion rate and decay properties of the homogeneous solution, our results demonstrate that the Euler–Poisson system admits a globally classical solution for initial data that are small perturbations to the homogeneous solution. Additionally, we establish that the solution asymptotically approaches the homogeneous solution as time tends to infinity. The theoretical framework is then applied to various types of perfect fluids, including isothermal gases, Chaplygin gases, and polytropic gases.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"66 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697061","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}
Pub Date : 2024-11-25DOI: 10.1088/1361-6382/ad8f27
William Delplanque and Evgeny Skvortsov
Massive higher spin fields are notoriously difficult to introduce interactions when they are described by symmetric (spin)-tensors. An alternative approach is to use chiral description that does not have unphysical longitudinal modes. For low spin fields we show that chiral and symmetric approaches can be related via a family of invertible change of variables (equivalent to parent actions), which should facilitate introduction of consistent interactions in the symmetric approach and help to control parity in the chiral one. We consider some examples of electromagnetic and gravitational interactions and their transmutations when going to the chiral formulation. An interesting feature of the relation is how second class constraints get eliminated while preserving Lorentz invariance.
{"title":"Symmetric vs. chiral approaches to massive fields with spin","authors":"William Delplanque and Evgeny Skvortsov","doi":"10.1088/1361-6382/ad8f27","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8f27","url":null,"abstract":"Massive higher spin fields are notoriously difficult to introduce interactions when they are described by symmetric (spin)-tensors. An alternative approach is to use chiral description that does not have unphysical longitudinal modes. For low spin fields we show that chiral and symmetric approaches can be related via a family of invertible change of variables (equivalent to parent actions), which should facilitate introduction of consistent interactions in the symmetric approach and help to control parity in the chiral one. We consider some examples of electromagnetic and gravitational interactions and their transmutations when going to the chiral formulation. An interesting feature of the relation is how second class constraints get eliminated while preserving Lorentz invariance.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"71 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697134","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}
Pub Date : 2024-11-21DOI: 10.1088/1361-6382/ad8f8c
Samarth Chawla, Kwinten Fransen and Cynthia Keeler
We embed the Penrose limit into the Weyl classical double copy. Thereby, we provide a lift of the double copy properties of plane wave spacetimes into black hole geometries and we open a novel avenue towards taking the classical double copy beyond statements about algebraically special backgrounds. In particular, the Penrose limit, viewed as the leading order Fermi coordinate expansion around a null geodesic, complements approaches leveraging asymptotic flatness such as the asymptotic Weyl double copy. Along the way, we show how our embedding of the Penrose limit within the Weyl double copy naturally fixes the functional ambiguity in the double copy for Petrov type N spacetimes. We also highlight the utility of a spinorial approach to the Penrose limit. In particular, we use this spinorial approach to derive a simple analytical expression for arbitrary Penrose limits of four-dimensional, vacuum type D spacetimes.
我们将彭罗斯极限嵌入韦尔经典双副本中。因此，我们将平面波时空的双副本特性提升到了黑洞几何中，并为经典双副本超越代数特殊背景的声明开辟了一条新途径。特别是，彭罗斯极限被视为围绕空大地线的前阶费米坐标展开，补充了利用渐近平坦性（如渐近韦尔双副本）的方法。同时，我们还展示了我们如何将彭罗斯极限嵌入韦尔双副本中，自然地解决了彼得罗夫 N 型空间双副本中的函数模糊性问题。我们还强调了彭罗斯极限自旋方法的实用性。特别是，我们利用这种自旋方法推导出了四维真空 D 型空间的任意彭罗斯极限的简单分析表达式。
{"title":"The Penrose limit of the Weyl double copy","authors":"Samarth Chawla, Kwinten Fransen and Cynthia Keeler","doi":"10.1088/1361-6382/ad8f8c","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8f8c","url":null,"abstract":"We embed the Penrose limit into the Weyl classical double copy. Thereby, we provide a lift of the double copy properties of plane wave spacetimes into black hole geometries and we open a novel avenue towards taking the classical double copy beyond statements about algebraically special backgrounds. In particular, the Penrose limit, viewed as the leading order Fermi coordinate expansion around a null geodesic, complements approaches leveraging asymptotic flatness such as the asymptotic Weyl double copy. Along the way, we show how our embedding of the Penrose limit within the Weyl double copy naturally fixes the functional ambiguity in the double copy for Petrov type N spacetimes. We also highlight the utility of a spinorial approach to the Penrose limit. In particular, we use this spinorial approach to derive a simple analytical expression for arbitrary Penrose limits of four-dimensional, vacuum type D spacetimes.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"71 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678311","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}
Pub Date : 2024-11-21DOI: 10.1088/1361-6382/ad7cb7
Bernard Hall, Sudhagar Suyamprakasam, Nairwita Mazumder, Anupreeta More and Sukanta Bose
Noise in various interferometer systems can sometimes couple non-linearly to create excess noise in the gravitational wave (GW) strain data. Third-order statistics, such as bicoherence and biphase, can identify these couplings and help discriminate those occurrences from astrophysical GW signals. However, the conventional analysis can yield large bicoherence values even when no phase-coupling is present, thereby, resulting in false identifications. Introducing artificial phase randomization in computing the bicoherence reduces such occurrences with negligible impact on its effectiveness for detecting true phase-coupled disturbances. We demonstrate this property with simulated disturbances—focusing only on short-duration ones (lasting up to a few seconds) and employing mainly the auto-bicoherence in this work. Statistical hypothesis testing is used for distinguishing phase-coupled disturbances from non-phase coupled ones when employing the phase-randomized bicoherence. We also obtain an expression for the bicoherence value that minimizes the sum of the probabilities of false positives and false negatives. This can be chosen as a threshold for shortlisting bicoherence triggers for further scrutiny for the presence of non-linear coupling. Finally, the utility of the phase-randomized bicoherence analysis in GW time-series data is demonstrated for the following three scenarios: (1) Finding third-order statistical similarities within categories of noise transients, such as blips and koi fish. If these non-Gaussian noise transients, or glitches, have a common source, their bicoherence maps can have similarities arising from common bifrequencies related to that source. (2) Differentiating linear or non-linear phase-coupled glitches from compact binary coalescence signals through their bicoherence maps. This is explained with a simulated signal. (3) Identifying repeated bifrequencies in the second and third observation runs (i.e. O2 and O3) of LIGO and Virgo.
{"title":"Identifying noise transients in gravitational-wave data arising from nonlinear couplings","authors":"Bernard Hall, Sudhagar Suyamprakasam, Nairwita Mazumder, Anupreeta More and Sukanta Bose","doi":"10.1088/1361-6382/ad7cb7","DOIUrl":"https://doi.org/10.1088/1361-6382/ad7cb7","url":null,"abstract":"Noise in various interferometer systems can sometimes couple non-linearly to create excess noise in the gravitational wave (GW) strain data. Third-order statistics, such as bicoherence and biphase, can identify these couplings and help discriminate those occurrences from astrophysical GW signals. However, the conventional analysis can yield large bicoherence values even when no phase-coupling is present, thereby, resulting in false identifications. Introducing artificial phase randomization in computing the bicoherence reduces such occurrences with negligible impact on its effectiveness for detecting true phase-coupled disturbances. We demonstrate this property with simulated disturbances—focusing only on short-duration ones (lasting up to a few seconds) and employing mainly the auto-bicoherence in this work. Statistical hypothesis testing is used for distinguishing phase-coupled disturbances from non-phase coupled ones when employing the phase-randomized bicoherence. We also obtain an expression for the bicoherence value that minimizes the sum of the probabilities of false positives and false negatives. This can be chosen as a threshold for shortlisting bicoherence triggers for further scrutiny for the presence of non-linear coupling. Finally, the utility of the phase-randomized bicoherence analysis in GW time-series data is demonstrated for the following three scenarios: (1) Finding third-order statistical similarities within categories of noise transients, such as blips and koi fish. If these non-Gaussian noise transients, or glitches, have a common source, their bicoherence maps can have similarities arising from common bifrequencies related to that source. (2) Differentiating linear or non-linear phase-coupled glitches from compact binary coalescence signals through their bicoherence maps. This is explained with a simulated signal. (3) Identifying repeated bifrequencies in the second and third observation runs (i.e. O2 and O3) of LIGO and Virgo.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"197 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678310","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}
Pub Date : 2024-11-20DOI: 10.1088/1361-6382/ad8f8a
Jacek Aleksander Gruca, Ankit Kumar, Ray Ganardi, Paramasivan Arumugam, Karolina Kropielnicka and Tomasz Paterek
The Schrödinger–Newton (SN) model is a semi-classical theory in which, in addition to mutual attraction, massive quantum particles interact with their own gravitational fields. While there are many studies on the phenomenology of single particles, correlation dynamics in multipartite systems is largely unexplored. Here, we show that the SN interactions preserve the product form of the initial state of a many-body system, yet on average agreeing with classical mechanics of continuous mass distributions. This leads to a simple test of the model, based on verifying bipartite gravitational evolution towards non-product states. We show using standard quantum mechanics that, with currently accessible single-particle parameters, two masses released from harmonic traps get correlated well before any observable entanglement is accumulated. Therefore, the SN model can be tested with setups aimed at observation of gravitational entanglement with significantly relaxed requirements on coherence time. We also present a mixed-state extension of the model that avoids superluminal signaling.
薛定谔-牛顿（SN）模型是一种半经典理论，其中除了相互吸引之外，大质量量子粒子还与自身的引力场相互作用。关于单粒子现象学的研究很多，但多粒子系统中的相关动力学在很大程度上尚未被探索。在这里，我们证明了SN相互作用保留了多体系统初始状态的乘积形式，但平均而言与质量连续分布的经典力学一致。由此，我们可以对模型进行一个简单的检验，即验证向非积态的双向引力演化。我们用标准量子力学证明，利用目前可获得的单粒子参数，从谐波陷阱释放的两个质量在积累任何可观测到的纠缠之前就会发生关联。因此，可以用旨在观测引力纠缠的设置来测试 SN 模型，同时大大放宽对相干时间的要求。我们还提出了该模型的混合态扩展，避免了超光速信号传递。
{"title":"Correlations and signaling in the Schrödinger–Newton model","authors":"Jacek Aleksander Gruca, Ankit Kumar, Ray Ganardi, Paramasivan Arumugam, Karolina Kropielnicka and Tomasz Paterek","doi":"10.1088/1361-6382/ad8f8a","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8f8a","url":null,"abstract":"The Schrödinger–Newton (SN) model is a semi-classical theory in which, in addition to mutual attraction, massive quantum particles interact with their own gravitational fields. While there are many studies on the phenomenology of single particles, correlation dynamics in multipartite systems is largely unexplored. Here, we show that the SN interactions preserve the product form of the initial state of a many-body system, yet on average agreeing with classical mechanics of continuous mass distributions. This leads to a simple test of the model, based on verifying bipartite gravitational evolution towards non-product states. We show using standard quantum mechanics that, with currently accessible single-particle parameters, two masses released from harmonic traps get correlated well before any observable entanglement is accumulated. Therefore, the SN model can be tested with setups aimed at observation of gravitational entanglement with significantly relaxed requirements on coherence time. We also present a mixed-state extension of the model that avoids superluminal signaling.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"80 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673448","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}
Pub Date : 2024-11-19DOI: 10.1088/1361-6382/ad8ea4
Hideki Maeda and Cristián Martínez
Without specifying a matter field nor imposing energy conditions, we study Killing horizons in -dimensional static solutions in general relativity with an -dimensional Einstein base manifold. Assuming linear relations and near a Killing horizon between the energy density ρ, radial pressure , and tangential pressure p2 of the matter field, we prove that any non-vacuum solution satisfying ( ) or does not admit a horizon as it becomes a curvature singularity. For and , non-vacuum solutions admit Killing horizons, on which there exists a matter field only for and , which are of the Hawking–Ellis type I and type II, respectively. Differentiability of the metric on the horizon depends on the value of , and non-analytic extensions beyond the horizon are allowed for . In particular, solutions can be attached to the Schwarzschild–Tangherlini-type vacuum solution at the Killing horizon in at least a regular manner without a lightlike thin shell. We generalize some of those results in Lovelock gravity with a maximally symmetric base manifold.
{"title":"Existence and absence of Killing horizons in static solutions with symmetries","authors":"Hideki Maeda and Cristián Martínez","doi":"10.1088/1361-6382/ad8ea4","DOIUrl":"https://doi.org/10.1088/1361-6382/ad8ea4","url":null,"abstract":"Without specifying a matter field nor imposing energy conditions, we study Killing horizons in -dimensional static solutions in general relativity with an -dimensional Einstein base manifold. Assuming linear relations and near a Killing horizon between the energy density ρ, radial pressure , and tangential pressure p2 of the matter field, we prove that any non-vacuum solution satisfying ( ) or does not admit a horizon as it becomes a curvature singularity. For and , non-vacuum solutions admit Killing horizons, on which there exists a matter field only for and , which are of the Hawking–Ellis type I and type II, respectively. Differentiability of the metric on the horizon depends on the value of , and non-analytic extensions beyond the horizon are allowed for . In particular, solutions can be attached to the Schwarzschild–Tangherlini-type vacuum solution at the Killing horizon in at least a regular manner without a lightlike thin shell. We generalize some of those results in Lovelock gravity with a maximally symmetric base manifold.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"54 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670908","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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