International Journal of Modern Physics D最新文献_第4页

Quintessential Inflation and curvaton reheating 典型的膨胀和曲率再加热

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-21 DOI: 10.1142/s021827182350092x

Abhineet Agarwal, Sabit Bekov, Kairat Myrzakulov

引用次数: 3

Stability and pair production of scalars in the charged Einstein-ModMax black hole spacetime 带电爱因斯坦- modmax黑洞时空中标量的稳定性和对产生

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-20 DOI: 10.1142/s0218271823500992

Haryanto M. Siahaan

引用次数: 0

General formulae for the periapsis shift of a quasi-circular orbit in static spherically symmetric spacetimes and the active gravitational mass density 静态球对称时空中准圆轨道近点位移和活动重力质量密度的一般公式

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-20 DOI: 10.1142/s0218271823500980

Tomohiro Harada, Takahisa Igata, Hiromi Saida, Yohsuke Takamori

{"title":"General formulae for the periapsis shift of a quasi-circular orbit in static spherically symmetric spacetimes and the active gravitational mass density","authors":"Tomohiro Harada, Takahisa Igata, Hiromi Saida, Yohsuke Takamori","doi":"10.1142/s0218271823500980","DOIUrl":"https://doi.org/10.1142/s0218271823500980","url":null,"abstract":"We study the periapsis shift of a quasi-circular orbit in general static spherically symmetric spacetimes. We derive two formulae in full order with respect to the gravitational field, one in terms of the gravitational mass $m$ and the Einstein tensor and the other in terms of the orbital angular velocity and the Einstein tensor. These formulae reproduce the well-known ones for the forward shift in the Schwarzschild spacetime. In a general case, the shift deviates from that in the vacuum spacetime due to a particular combination of the components of the Einstein tensor at the radius $r$ of the orbit. The formulae give a backward shift due to the extended-mass effect in Newtonian gravity. In general relativity, in the weak-field and diffuse regime, the active gravitational mass density, $rho_{A}=(epsilon+p_{r}+2p_{t})/c^{2}$, plays an important role, where $epsilon$, $p_{r}$, and $p_{t}$ are the energy density, the radial stress, and the tangential stress of the matter field, respectively. We show that the shift is backward if $rho_{A}$ is beyond a critical value $rho_{c}simeq 2.8times 10^{-15} mbox{g}/mbox{cm}^{3} (m/M_{odot})^{2}(r/mbox{au})^{-4}$, while a forward shift greater than that in the vacuum spacetime instead implies $rho_{A}<0$, i.e., the violation of the strong energy condition, and thereby provides evidence for dark energy. We obtain new observational constraints on $rho_{A}$ in the Solar System and the Galactic Centre.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":"81 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135566613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Timelike Geodesic Congruence in the Simplest Solutions of General Relativity with Quantum-Improved Metric Tensor 广义相对论最简解中量子改进度量张量的类时测地线同余

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-20 DOI: 10.1142/s0218271823500979

A. Nasser Tawfik, T. F. Dabash

引用次数: 0

Shadows and photon rings of a spherically accreting Kehagias-Sfetsos black hole 球形吸积Kehagias-Sfetsos黑洞的阴影和光子环

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-18 DOI: 10.1142/s0218271823500888

Mohaddese Heydari-Fard, Malihe Heydari-Fard, Nematollah Riazi

引用次数: 1

Stability investigations of isotropic and anisotropic exponential inflation in the Starobinsky-Bel-Robinson gravity Starobinsky-Bel-Robinson重力中各向同性和各向异性指数膨胀的稳定性研究

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-17 DOI: 10.1142/s0218271823500876

Tuan Q. Do, Duy H. Nguyen, Tuyen M. Pham

引用次数: 2

Balancing multiple charge particle excess with baryon asymmetry 用重子不对称平衡多电荷粒子过剩

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-13 DOI: 10.1142/s0218271823400059

Vitaly A. Beylin, Maxim Yu. Khlopov, Danila O. Sopin

引用次数: 0

Drake equation of search for extraterrestrial intelligence: a proposal for modification in the light of Dirac's large number hypothesis 寻找地外智慧的德雷克方程:根据狄拉克大数假设修正的建议

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-13 DOI: 10.1142/s0218271823500943

Saibal Ray, Soham Ray, Issa Al-Amri, S.K. Maurya, K.P. Manith Banula

引用次数: 0

Is it time to rethink quantum gravity? 是时候重新思考量子引力了吗?

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-13 DOI: 10.1142/s0218271823420245

Jonathan Oppenheim

引用次数: 1

Normalization of the vacuum and the ultraviolet completion of Einstein gravity 真空归一化和爱因斯坦引力的紫外完成

4区物理与天体物理

International Journal of Modern Physics D Pub Date : 2023-10-13 DOI: 10.1142/s0218271823500967

Philip D. Mannheim

{"title":"Normalization of the vacuum and the ultraviolet completion of Einstein gravity","authors":"Philip D. Mannheim","doi":"10.1142/s0218271823500967","DOIUrl":"https://doi.org/10.1142/s0218271823500967","url":null,"abstract":"Second-order-derivative plus fourth-order-derivative gravity is the ultraviolet completion of second-order-derivative quantum Einstein gravity. While it achieves renormalizability through states of negative Dirac norm, the unitarity violation that this would entail can be postponed to Planck energies. As we show in this paper the theory has a different problem, one that occurs at all energy scales, namely that the Dirac norm of the vacuum of the theory is not finite. To establish this we present a procedure for determining the norm of the vacuum in any quantum field theory. With the Dirac norm of the vacuum of the second-order-derivative plus fourth-order-derivative theory not being finite, the Feynman rules that are used to establish renormalizability are not valid, as is the assumption that the theory can be used as an effective theory at energies well below the Planck scale. This lack of finiteness is also manifested in the fact that the Minkowski path integral for the theory is divergent. Because the vacuum Dirac norm is not finite, the Hamiltonian of the theory is not Hermitian. However, it turns out to be $PT$ symmetric. And when one continues the theory into the complex plane and uses the $PT$ symmetry inner product, viz. the overlap of the left-eigenstate of the Hamiltonian with its right-eigenstate, one then finds that for the vacuum this norm is both finite and positive, the Feynman rules now are valid, the Minkowski path integral now is well behaved, and the theory now can serve as a low energy effective theory. Consequently, the theory can now be offered as a fully consistent, unitary and renormalizable theory of quantum gravity.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135918169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0