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Jing-Yi Zhang

Publications and source records attributed to Jing-Yi Zhang.

7 recordsLinked to original sources
arXiv2023

Corrections to the thermodynamic quantities of Bose system by the generalized uncertainty principle

This paper investigated the Bose system in a spherical shell close to the black hole horizon. Several thermodynamic quantities of the Bose system are derived, which are different from those in the flat spacetime, by introducing the generalized uncertainty principle (GUP) into the grand partition function of statistical mechanics. The internal energy and the pressure of the Bose system appear to have a correction term of $T^6$, while the entropy has a $T^5$ correction term where both the coefficients are functions of the spacetime component $g_{00}$ and the brick-wall model parameter $ε$. Taking the Schwarzschild black hole as an example, the physical quantities of the shell such as temperature, pressure and entropy are calculated for the final stage of black hole radiation.

gr-qc↗
arXiv2022

Photometric redshift estimation of galaxies in the DESI Legacy Imaging Surveys

The accurate estimation of photometric redshifts plays a crucial role in accomplishing science objectives of the large survey projects. The template-fitting and machine learning are the two main types of methods applied currently. Based on the training set obtained by cross-correlating the DESI Legacy Imaging Surveys DR9 galaxy catalogue and SDSS DR16 galaxy catalogue, the two kinds of methods are used and optimized, such as EAZY for template-fitting approach and CATBOOST for machine learning. Then the created models are tested by the cross-matched samples of the DESI Legacy Imaging SurveysDR9 galaxy catalogue with LAMOST DR7, GAMA DR3 and WiggleZ galaxy catalogues. Moreover three machine learning methods (CATBOOST, Multi-Layer Perceptron and Random Forest) are compared, CATBOOST shows its superiority for our case. By feature selection and optimization of model parameters, CATBOOST can obtain higher accuracy with optical and infrared photometric information, the best performance ($MSE=0.0032$, $σ_{NMAD}=0.0156$ and $O=0.88$ per cent) with $g \le 24.0$, $r \le 23.4$ and $z \le 22.5$ is achieved. But EAZY can provide more accurate photometric redshift estimation for high redshift galaxies, especially beyond the redhisft range of training sample. Finally, we finish the redshift estimation of all DESI DR9 galaxies with CATBOOST and EAZY, which will contribute to the further study of galaxies and their properties.

astro-ph.IM↗
arXiv2022

Thermodynamic geometric analysis of conventional black holes under f(R) gravity

In this article, we consider a conventional black hole under f(R) gravity. Due to the small fluctuations around the equilibrium state, we have summarized the expression of the modified thermodynamic entropy of this black hole. At the same time, we also studied the geometric thermodynamics (GTD) of black holes, and studied the adaptability of the curvature scalar of the geometric thermodynamics method to the phase transition point of the black hole. In addition, we also studied the influence of the modified parameters on the thermodynamic behavior of black holes.

gr-qc↗
arXiv2021

Photometric Redshift Estimation of BASS DR3 Quasars by Machine Learning

Correlating BASS DR3 catalogue with ALLWISE database, the data from optical and infrared information are obtained. The quasars from SDSS are taken as training and test samples while those from LAMOST are considered as external test sample. We propose two schemes to construct the redshift estimation models with XGBoost, CatBoost and Random forest. One scheme (namely one-step model) is to predict photometric redshifts directly based on the optimal models created by these three algorithms; the other scheme (namely two-step model) is to firstly classify the data into low- and high- redshift datasets, and then predict photometric redshifts of these two datasets separately. For one-step model, the performance of these three algorithms on photometric redshift estimation is compared with different training samples, and CatBoost is superior to XGBoost and Random forest. For two-step model, the performance of these three algorithms on the classification of low- and high-redshift subsamples are compared, and CatBoost still shows the best performance. Therefore CatBoost is regard as the core algorithm of classification and regression in two-step model. By contrast with one-step model, two-step model is optimal when predicting photometric redshift of quasars, especially for high redshift quasars. Finally the two models are applied to predict photometric redshifts of all quasar candidates of BASS DR3. The number of high redshift quasar candidates is 3938 (redshift $\ge 3.5$) and 121 (redshift $\ge 4.5$) by two-step model. The predicted result will be helpful for quasar research and follow up observation of high redshift quasars.

astro-ph.IM↗
arXiv2016

A modified thermodynamics method to generate exact solutions of the Einstein equations

We modify the method to generate the exact solutions of the Einstein equations basing on the laws of thermodynamics. Firstly, the Komar mass is used to take the place of the Misner-Sharp energy which is used in the original methods, and then several exact solutions of Einstein equations are obtained, including the black hole solution which surrounded by quintessence. Moreover, the geometry surface gravity defined by Komar mass is obtained. Secondly, we use both the Komar mass and the ADM mass to modify such method, and the similar results are obtained. Moreover, with some generalize added to the definition of the ADM mass, our method can be generalized to global monopole sapcetime.

gr-qc↗
arXiv2010

A note on the Hawking radiation calculated by the quasi-classical tunneling method

Since Parikh and Wilczek's tunneling method was proposed, there have been many generalizations, such as its application to massive charged particles' tunneling and other spacetimes. Moreover, a variant tunneling method was also recently proposed by Angheben et al that it was independent of coordinates. However, there are some subtleties in the calculation of Hawking radiation, and particularly is the so-called factor of 2 problem during calculating the Hawking temperature. The most popular opinion on this problem is that it is just a problem of the choice of coordinates. However, following other treatments we show that we can also consider this problem as a problem that we do not consider the contribution from P(absorption). Moreover, we also give some subtleties in the balance method and some comparisons with other treatments. In addition, as Parikh and Wilczek's original works have showed that if one takes the tunneling particles' back-reaction into account, the Hawking radiation would be modified, and this modification is underlying consistent with the unitary theory, we further find that this modification is also underlying correlated with the laws of black hole thermodynamics. Furthermore, we show that this tunneling method may be valid just when the tunneling process is reversible.

gr-qc↗