Shuo Cao - Beijing Normal University

Shuo Cao
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Name
Shuo Cao
Affiliation
Beijing Normal University
City
Beijing
Country
China

Pubs By Year

Pub Categories

 
Cosmology and Nongalactic Astrophysics (28)
 
General Relativity and Quantum Cosmology (4)
 
Physics - Mesoscopic Systems and Quantum Hall Effect (3)
 
Quantum Physics (2)
 
Physics - Optics (2)
 
High Energy Physics - Theory (2)
 
Astrophysics of Galaxies (1)

Publications Authored By Shuo Cao

A new compilation of $120$ angular-size/redshift data for compact radio quasars from very-long-baseline interferometry (VLBI) surveys motivates us to revisit the interaction between dark energy and dark matter with these probes reaching high redshifts $z\sim 3.0$. In this paper, we investigate observational constraints on different phenomenological interacting dark energy (IDE) models with the intermediate-luminosity radio quasars acting as individual standard rulers, combined with the newest BAO and CMB observation from Planck results acting as statistical rulers. Read More

Based on a mass-selected sample of galaxy-scale strong gravitational lenses from the SLACS, BELLS, LSD and SL2S surveys and using a well-motivated fiducial set of lens-galaxy parameters we tested the weak-field metric on kiloparsec scales and found a constraint on the post-Newtonian parameter $\gamma = 0.995^{+0.037}_{-0. Read More

In this paper, by analyzing the thermodynamic properties of charged AdS black hole and asymptotically flat space-time charged black hole in the vicinity of the critical point, we establish the correspondence between the thermodynamic parameters of asymptotically flat space-time and nonasymptotically flat space-time, based on the equality of black hole horizon area in the two different space-time. The relationship between the cavity radius (which is introduced in the study of asymptotically flat space-time charged black holes) and the cosmological constant (which is introduced in the study of nonasymptotically flat space-time) is determined. The establishment of the correspondence between the thermodynamics parameters in two different space-time is beneficial to the mutual promotion of different time-space black hole research, which is helpful to understand the thermodynamics and quantumproperties of black hole in space-time. Read More

In this paper we use a recently compiled data set, which comprises 118 galactic-scale strong gravitational lensing (SGL) systems to constrain the statistic property of SGL system, as well as the curvature of universe without assuming any fiducial cosmological model. Based on the singular isothermal ellipsoid (SIE) model of SGL system, we obtain that the constrained curvature parameter $\Omega_{\rm k}$ is close to zero from the SGL data, which is consistent with the latest result of planck measurement. More interestingly, we find that the parameter $f$ in the SIE model is strongly correlated with the curvature $\Omega_{\rm k}$. Read More

In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with $0.0035Read More

In order to achieve a deeper understanding of gravity theories, it is important to further investigate the thermodynamic properties of black hole at the critical point, besides the phase transition and critical behaviors. In this paper, by using Maxwell's equal area law, we choose $T,Q,\Phi$ as the state parameters and study the phase equilibrium problem of general $(n+1)$-dimensional RN-AdS black holes thermodynamic system. The boundary of the two-phase coexistence region and its isotherm and isopotential lines are presented, which may provide theoretical foundation for studying the phase transition and phase structure of black hole systems. Read More

Two-point diagnostics $Om(z_i,z_j)$ and $Omh^2(z_i,z_j)$ have been introduced as an interesting tool for testing the validity of the $\Lambda$CDM model. Quite recently, Sahni, Shafieloo $\&$ Starobinsky (2014) combined two independent measurements of $H(z)$ from BAO data with the value of the Hubble constant $H_0$, and used the second of these diagnostics to test the $\Lambda$CDM model. Their result indicated a considerable tension between observations and predictions of the $\Lambda$CDM model. Read More

We use 118 strong gravitational lenses observed by the SLACS, BELLS, LSD and SL2S surveys to constrain the total mass profile and the profile of luminosity density of stars (light-tracers) in elliptical galaxies up to redshift $z \sim 1$. Assuming power-law density profiles for the total mass density, $\rho=\rho_0(r/r_0)^{-\alpha}$, and luminosity density, $\nu=\nu_0(r/r_0)^{-\delta}$, we investigate the power law index and its first derivative with respect to the redshift. Using Monte Carlo simulations of the posterior likelihood taking the Planck's best-fitted cosmology as a prior, we find $\gamma= 2. Read More

In this paper, assuming the validity of distance duality relation, $\eta=D_L(z)(1+z)^{-2}/D_A(z)=1$, where $D_A(z)$ and $D_L(z)$ are the angular and the luminosity distance respectively, we explore two kinds of gas mass density profiles of clusters: the isothermal $\beta$ model and the non-isothermal double-$\beta$ model. In our analysis, performed on 38 massive galaxy clusters observed by \textit{Chandra} (within the redshift range of $0.14Read More

We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. Read More

Under very general assumptions of metric theory of spacetime, photons traveling along null geodesics and photon number conservation, two observable concepts of cosmic distance, i.e. the angular diameter and the luminosity distances are related to each other by the so-called distance duality relation (DDR) $D^L=D^A(1+z)^2$. Read More

In this paper, we used standard rulers and standard candles (separately and jointly) to explore five popular dark energy models under assumption of spatial flatness of the Universe. As standard rulers, we used a data set comprising 118 galactic-scale strong lensing systems (individual standard rulers if properly calibrated for the mass density profile) combined with BAO diagnostics (statistical standard ruler). Supernovae Ia served asstandard candles. Read More

In this paper, we assemble a catalog of 118 strong gravitational lensing systems from SLACS, BELLS, LSD and SL2S surveys and use them to constrain the cosmic equation of state. In particular we consider two cases of dark energy phenomenology: $XCDM$ model where dark energy is modeled by a fluid with constant $w$ equation of state parameter and in Chevalier - Polarski - Linder (CPL) parametrization where $w$ is allowed to evolve with redshift: $w(z) = w_0 + w_1 \frac{z}{1+z}$. We assume spherically symmetric mass distribution in lensing galaxies, but relax the rigid assumption of SIS model in favor to more general power-law index $\gamma$, also allowing it to evolve with redshifts $\gamma(z)$. Read More

In quantum theory of gravity, we expect the Lorentz Invariance Violation (LIV) and the modification of the dispersion relation between energy and momentum for photons. The effect of the energy-dependent velocity due to the modified dispersion relation for photons was studied in the standard cosmological context by using a sample of Gamma Ray Bursts (GRBs). In this paper we mainly discuss the possible LIV effect by using different cosmological models for the accelerating universe. Read More

Cosmological applications of the "redshift - angular size" test require knowledge of the linear size of the "standard rod" used. In this paper, we study the properties of a large sample of 140 milliarcsecond compact radio sources with flux densities measured at 6 cm and 20 cm, compiled by Gurvits et al.(1999). Read More

Recently, Sahni, Shafielo o & Starobinsky (2014) combined two independent measurements of $H(z)$ from BAO data with the value of the Hubble constant $H_0 = H(z=0)$, in order to test the cosmological constant hypothesis by means of an improved version of the $Om$ diagnostic. Their result indicated a considerable tension between observations and predictions of the $\Lambda$CDM model. However, such strong conclusion was based only on three measurements of $H(z)$. Read More

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. Read More

Using a relatively complete observational data concerning four angular diameter distance (ADD) measurements and %synthetic combined SN+GRB observations representing current luminosity distance (LD) data, this paper investigates the %tension between compatibility of these two cosmological distances considering three classes of dark energy equation of state (EoS) reconstruction. In particular, we use strongly gravitationally lensed systems from various large systematic gravitational lens surveys and galaxy clusters, which yield the Hubble constant independent ratio between two angular diameter distances $D_{ls}/D_s$ data. Our results demonstrate that, with more general categories of standard ruler data, ADD and LD data are compatible at $1\sigma$ level. Read More

We present a new analysis of HST, Spitzer telescope imaging and VLT imaging and spectroscopic data of a bright lensed galaxy at $z$=1.0334 in the lensing cluster Abell~2667. Using this high-resolution imaging we present an updated lens model that allows us to fully understand the lensing geometry and reconstruct the lensed galaxy in the source plane. Read More

We report a photoluminescence (PL) spectroscopy study of charge state control in single self-assembled InAs/GaAs quantum dots by applying electric and/or magnetic fields at 4.2 K. Neutral and charged exciton complexes were observed under applied bias voltages from -0. Read More

We constrain the scalar field dark energy model with an inverse power-law potential, i.e., $V(\phi)\propto {\phi}^{-\alpha}$ ($\alpha>0$), from a set of recent cosmological observations by compiling an updated sample of Hubble parameter measurements including 30 independent data points. Read More

2012Nov
Affiliations: 1Beijing Normal University, 2University of Naples "Federico II", 3University of Naples "Federico II", 4Beijing Normal University

We present a multi-wavelength study of the gravitational lens COSMOS J095930+023427 (z=0.89), together with the associated galaxy group located at $z\sim0.7$ along the line of sight and the lensed background galaxy. Read More

We use the new gamma-ray bursts (GRBs) data, combined with the baryon acoustic oscillation(BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release, the newly obtained $A$ parameter at $z=0.6$ from the WiggleZ Dark Energy Survey, the cosmic microwave background (CMB) observations from the 7-Year Wilkinson Microwave Anisotropy Probe (WMAP7) results, and the type Ia supernovae (SNeIa) from Union2 set, to constrain a phenomenological model describing possible interactions between dark energy and dark matter, which was proposed to alleviate the coincidence problem of the standard $\Lambda$CDM model. By using the Markov Chain Monte Carlo (MCMC) method, we obtain the marginalized $1\sigma$ constraints $\Omega_{m}=0. Read More

2012Jun
Affiliations: 1Beijing Normal University, 2University of Naples "Federico II", 3Beijing Normal University

We study the redshift distribution of two samples of early-type gravitational lenses, extracted from a larger collection of 122 systems, to constrain the cosmological constant in the LCDM model and the parameters of a set of alternative dark energy models (XCDM, Dvali-Gabadadze-Porrati and Ricci dark energy models), under a spatially flat universe. The likelihood is maximized for $\Omega_\Lambda= 0.70 \pm 0. Read More

We constrain a unified dark matter (UDM) model from the latest observational data. This model assumes that the dark sector is degenerate. Dark energy and dark matter are the same component. Read More

Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structures, formations, and evolutions). Now several hundreds of strong lens systems produced by massive galaxies have been discovered, which may form well-defined samples useful for statistical analyses. To collect a relatively complete lens redshift data from various large systematic surveys of gravitationally lensed quasars and check the possibility to use it as a future complementarity to other cosmological probes. Read More

Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances $D_{ds}/D_s$ from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). Read More

In order to test if there is energy transfer between dark energy and dark matter, we investigate cosmological constraints on two forms of nontrivial interaction between the dark matter sector and the sector responsible for the acceleration of the universe, in light of the newly revised observations including OHD, CMB, BAO and SNe Ia. More precisely, we find the same tendencies for both phenomenological forms of the interaction term $Q=3\gamma H\rho$, i.e. Read More

In this paper, we propose an accurate test of the distance-duality (DD) relation, $\eta=D_{L}(z)(1+z)^{-2}/D_{A}(z)=1$ (where $D_{L}$ and $D_{A}$ are the luminosity distances and angular diameter distances, respectively), with a combination of cosmological observational data of Type Ia Supernave (SNe Ia) from Union2 set and the galaxy cluster sample under an assumption of spherical model. In order to avoid bias brought by redshift incoincidence between observational data and to consider redshift error bars of both clusters and SNe Ia in analysis, we carefully choose the SNe Ia points which have the minimum acceptable redshift difference of the galaxy cluster sample ($|\Delta z|_{\rm min} =\sigma_{z, \rm SN}+\sigma_{z, \rm cluster}$). By assuming $\eta$ a constant and functions of the redshift parameterized by six different expressions, we find that there exists no conceivable evidence for variations in the DD relation concerning with observational data, since it is well satisfied within $1\sigma$ confidence level for most cases. Read More

We propose a new consistent method to test of the distance-duality (DD) relation which related angular diameter distances (DA) to the luminosity distances (DL) in a cosmology-independent way. In order to avoid any bias brought by redshift incoincidence between galaxy clusters and Type Ia Supernave (SNe Ia), as well as to ensure the integrity of the galaxy clusters samples, we obtain the luminosity distance of a certain SN Ia point at the same redshift of the corresponding galaxy cluster by interpolating from the nearby SNe Ia. With the observational data at the same redshifts of the angular diameter distances from the complete 38 galaxy cluster sample for the spherical model and the corrected luminosity distances interpolated from the Union2 set, we find that $\eta \equiv {D_L}{(1+z)}^{-2}/{D_A}=1$ is satisfied within $2\sigma$ confidence level for various parameterizations of $\eta(z)$, which are more stringent than previous testing results without considering redshift bias. Read More

The validity of distance duality relation, $\eta=D_L(z)(1+z)^{-2}/D_A(z)=1$, an exact result required by the Etherington reciprocity theorem, where $D_A(z)$ and $D_L(z)$ are the angular and luminosity distances, plays an essential part in cosmological observations and model constraints. In this paper, we investigate some consequences of such a relation by assuming $\eta$ a constant or a function of the redshift. In order to constrain the parameters concerning $\eta$, we consider two groups of cluster gas mass fraction data including 52 X-ray luminous galaxy clusters observed by Chandra in the redshift range $0. Read More

In order to test the possible interaction between dark energy and dark matter, we investigate observational constraints on a phenomenological scenario, in which the ratio between the dark energy and matter densities is proportional to the power law case of the scale factor, $r\equiv (\rho_X/\rho_m)\propto a^{\xi}$. By using the Markov chain Monte Carlo method, we constrain the phenomenological interacting dark energy model with the newly revised $H(z)$ data, as well as the cosmic microwave background (CMB) observation from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) results, the baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample and the type Ia supernovae (SNe Ia) from Union2 set. The best-fit values of the model parameters are $\Omega_{m0}=0. Read More

The interacting dark matter (IDM) scenario allows for the acceleration of the Universe without Dark Energy. We constrain the IDM model by using the newly revised observational data including $H(z)$ data and Union2 SNe Ia via the Markov chain Monte Carlo method. When mimicking the $\Lambda$CDM model, we obtain a more stringent upper limit to the effective annihilation term at $\kappa C_1\approx 10^{-3. Read More