arXiv subjects

Sen Guo

Publications and source records attributed to Sen Guo.

41 records · Page 3Linked to original sources

arXiv2022

The feature of shadow images and observed luminosity of the Bardeen black hole surrounded by different accretions

In this paper, by exploring the photon motion in the region near the Bardeen black hole, the shadow and observation properties of the black hole surrounded by various accretion models are studied. We analyzed the changes in shadow imaging and observation luminosity when the relevant physical parameters are changed. For the different spherical accretions background, one can find that the radius of shadow and the position of photon sphere do not change, but the observation intensity of shadow in the infalling accretion model is significantly lower than that of the static case. When the black hole is surrounded by an optically and thin disk accretion, the contribution of the photon rings, lensing rings and direct emission to the total observed flux has also been studied. Under the different forms of the emission modes, the result shows that the observed brightness is mainly determined by direct emission, while the lensing rings will provide a small part of the observation flux and the photon ring can provide a negligible observation flux. By comparing our results with the Schwarzschild spacetime, it is found that the existence or change of relevant status parameters will greatly affect the shape and observation intensity of black hole shadow. These results support that the change of state parameter will affect the spacetime structure, thus affecting the observation feature of black hole shadows.

hep-th↗

arXiv2021

Cooling-heating phase transition and critical behavior of the charged accelerating AdS black hole

We study the cooling-heating phase transition of the charged accelerating anti-de Sitter black hole in extended phase space, and investigate the critical behavior of this black hole in extended phase space. By calculating the thermodynamic quantities and state equation, we found that the charged accelerating AdS black hole as thermodynamic system is similar to the van der Waals system. The inversion temperature of this black hole is obtained, and cooling-heating and isenthalpic curves are plotted in T-P plane. Our results indicate that the inversion temperature for a given pressure increases with e, and the acceleration parameter has the opposite effect, which the cooling-heating curves decreases gradually with the the increases of a. We also analyse the influence of acceleration parameter on isenthalpic curves, implying that the phase transition point decreases with the increase of acceleration factor under constant pressure.

hep-th↗

arXiv2021

Hayward black hole heat engine efficiency in anti-de Sitter space

In this paper, we attempt to further study the heat engine efficiency for the regular black hole (BH) with an anti-de Sitter (AdS) background where the working material is the Hayward-AdS (HAdS) BH. In the extended phase space, we investigate the heat engine efficiency of the HAdS BH by defining the cosmological constant as the thermodynamic pressure $P$ and deriving the mechanical work from the $PdV$ terms. Then, we obtain the relation between the efficiency and the entropy/pressure and plot these function figures. Meanwhile, we compare the relation between the HAdS BH with that of the Bardeen-AdS (BAdS) BH, which is found that the efficiency of the HAdS BH increase with increase the magnetic charge $q$ in contrast to that of the BAdS BH decrease with increase the magnetic charge $q$. We found that the HAdS BH is more efficient than the BAdS BH, and guess that is related to the BH structure.

gr-qc↗

arXiv2019

Joule-Thomson expansion for the regular(Bardeen)-AdS black hole

In this paper, we attempt to study the Joule-Thomson expansion for the regular black hole in an anti-de Sitter background, and obtain the inversion temperature and curve for the Bardeen-AdS black hole in the extended phase space. We investigate the isenthalpic and inversion curves for the Bardeen-AdS black hole in the T-P plane to find the intersection points between them are exactly the inversion points discriminating the heating process from the cooling one. And, the inversion curve for the regular(Bardeen)-AdS black hole is not closed and there is only a lower inversion curve in contrast with that of the Van der Walls fluid. Most importantly, we find the ratio between the minimum inversion and critical temperature for the regular(Bardeen)-AdS black hole is 0.536622, which is always larger than all the already-known ratios for the singular black hole. This larger ratio for the Bardeen-AdS black hole in contrast with the singular black hole may stem from the fact that there is a repulsive de Sitter core near the origin of the regular black hole.

gr-qc↗

arXiv2019

Joule-Thomson Expansion of Hayward-AdS black hole

In this paper, we study Joule-Thomson expansion for Hayward-AdS black hole in the extended phase space, and obtain a Joule-Thomson expansion formula for the black hole. We plot the inversion and isenthalpic curves in the T-P plane, and determine the cooling-heating regions. The intersection points of the isenthalpic and inversion curves are exactly the inversion points discriminating the heating process from the cooling one.

gr-qc↗