Zobrazeno 1 - 10
of 462
pro vyhledávání: '"Gong, Yungui"'
The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a stellar-mass object s
Externí odkaz:
http://arxiv.org/abs/2408.15064
Autor:
Zhang, Chao, Gong, Yungui
We examine extreme mass ratio inspirals (EMRIs), where a charged compact object spirals into a supermassive black hole, in modified gravity theories with additional scalar or vector fields. Using the Teukolsky and generalized Sasaki-Nakamura formalis
Externí odkaz:
http://arxiv.org/abs/2407.07449
There is a duality in the observables $n_s$, $r$ and the inflaton potential between large and small $\eta_H$ for the constant-roll inflation if the slow-roll parameter $\epsilon_H$ is negligible. In general, the duality between $\eta_H$ and $\bar{\et
Externí odkaz:
http://arxiv.org/abs/2404.18548
Publikováno v:
Commun. Theor. Phys. 76 (2024) 095401
We investigate the constant-roll inflation with non-minimally kinetic coupling to the Einstein tensor. With the slow-roll parameter $\eta_\phi = -\ddot{\phi}/(H\dot{\phi})$ being a constant, we calculate the power spectra for scalar and tensor pertur
Externí odkaz:
http://arxiv.org/abs/2404.04978
Publikováno v:
Phys. Rev. D 109 (2024) 103532
Primordial black holes (PBHs) generated in the early Universe are considered as one of the candidates for dark matter. To produce PBHs with sufficient abundance, the primordial scalar power spectrum needs to be enhanced to the order of 0.01. Consider
Externí odkaz:
http://arxiv.org/abs/2401.16069
Publikováno v:
Phys. Rev. D 109, 104015 (2024)
In higher-dimensional theories, a graviton propagating in the bulk can follow a shorter path, known as a shortcut, compared to a photon propagating in a four-dimensional spacetime. Thus by combining the observations of gravitational waves and their e
Externí odkaz:
http://arxiv.org/abs/2312.17549
Publikováno v:
Eur. Phys. J. C 84, 738 (2024)
In this paper, we propose an approach to derive the brane cosmology in the $D$-dimensional braneworld model. We generalize the "bulk-based" approach by treating the 4-brane as a small perturbation to the $D$-dimensional spherically symmetric spacetim
Externí odkaz:
http://arxiv.org/abs/2312.17542
Publikováno v:
Phys. Lett. B 855 (2024) 138797
In this Letter, we present five analytical models in closed forms, each representing a supermassive black hole (SMBH) located at the center of a galaxy surrounded by dark matter (DM) halo. The density profile of the halo vanishes inside twice the Sch
Externí odkaz:
http://arxiv.org/abs/2311.12259
Publikováno v:
Commun. Theor. Phys. 76 (2024) 035401
In this paper, we consider the B\"ohmer-Vandersloot (BV) model of loop quantum black holes obtained from the improved dynamics approach. We adopt the Saini-Singh gauge, in which it was found analytically that the BV spacetime is geodesically complete
Externí odkaz:
http://arxiv.org/abs/2308.15574
Publikováno v:
Sci. China-Phys. Mech. Astron. 66, 120404 (2023)
The power-law parametrization for the energy density spectrum of gravitational wave (GW) background is a useful tool to study its physics and origin. While scalar induced secondary gravitational waves (SIGWs) from some particular models fit the signa
Externí odkaz:
http://arxiv.org/abs/2307.02467