pΞ−p\Xi^- Correlation in Relativistic Heavy Ion Collisions with Nucleon-Hyperon Interaction from Lattice QCD

On the basis of the $p\Xi^-$ interaction extracted from (2+1)-flavor lattice QCD simulations at the physical point, the momentum correlation of $p$ and $\Xi^-$ produced in relativistic heavy ion collisions is evaluated. $C_{\rm SL}(Q)$ defined by a ratio of the momentum correlations between the systems with different source sizes is shown to be largely enhanced at low momentum due to the strong attraction between $p$ and $\Xi^-$ in the $I=J=0$ channel. Thus, measuring this ratio at RHIC and LHC and its comparison to the theoretical analysis will give a useful constraint on the $p\Xi^-$ interaction.Comment: 4 pages, 2 figures; proceedings contribution for Quark Matter 201

Stationary distributions for a class of generalized Fleming-Viot processes

We identify stationary distributions of generalized Fleming-Viot processes with jump mechanisms specified by certain beta laws together with a parameter measure. Each of these distributions is obtained from normalized stable random measures after a suitable biased transformation followed by mixing by the law of a Dirichlet random measure with the same parameter measure. The calculations are based primarily on the well-known relationship to measure-valued branching processes with immigration.Comment: Published in at http://dx.doi.org/10.1214/12-AOP829 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Entanglement branching operator

We introduce an entanglement branching operator to split a composite entanglement flow in a tensor network which is a promising theoretical tool for many-body systems. We can optimize an entanglement branching operator by solving a minimization problem based on squeezing operators. The entanglement branching is a new useful operation to manipulate a tensor network. For example, finding a particular entanglement structure by an entanglement branching operator, we can improve a higher-order tensor renormalization group method to catch a proper renormalization flow in a tensor network space. This new method yields a new type of tensor network states. The second example is a many-body decomposition of a tensor by using an entanglement branching operator. We can use it for a perfect disentangling among tensors. Applying a many-body decomposition recursively, we conceptually derive projected entangled pair states from quantum states that satisfy the area law of entanglement entropy.Comment: 11 pages, 13 figure

Distances and lensing in cosmological void models

We study the distances and gravitational lensing in spherically symmetric inhomogeneous cosmological models consisting of inner and outer homogeneous regions which are connected by a single shell or double shells at the redshift $z_1 \sim 0.067$. The density and Hubble parameters in the inner region are assumed to be smaller and larger, respectively, than those in the outer region. It is found that at the stage $z_1 < z < 1.5$ the distances from an observer in the inner void-like region are larger than the counterparts (with equal $z$) in the corresponding homogeneous Friedmann models, and hence the magnitudes for the sources at this stage are larger. This effect of the void-like low-density region may explain the deviations of the observed [magnitude-redshift] relation of SNIa from the relation in homogeneous models, independently of the cosmological constant. When the position of the observer deviates from the center, moreover, it is shown that the distances are anisotropic and the images of remote sources are systematically deformed. The above relation at $z \geq 1.0$ and this anisotropy will observationally distinguish the role of the above void-like region from that of the positive cosmological constant. The influence on the time-delay measurement is also discussed.Comment: 14 pages, 11 postscript figures Equation numbers were corrected, Apj 529(2000) No.1 in pres

The two-parameter Poisson--Dirichlet point process

The two-parameter Poisson--Dirichlet distribution is a probability distribution on the totality of positive decreasing sequences with sum 1 and hence considered to govern masses of a random discrete distribution. A characterization of the associated point process (that is, the random point process obtained by regarding the masses as points in the positive real line) is given in terms of the correlation functions. Using this, we apply the theory of point processes to reveal the mathematical structure of the two-parameter Poisson--Dirichlet distribution. Also, developing the Laplace transform approach due to Pitman and Yor, we are able to extend several results previously known for the one-parameter case. The Markov--Krein identity for the generalized Dirichlet process is discussed from the point of view of functional analysis based on the two-parameter Poisson--Dirichlet distribution.Comment: Published in at http://dx.doi.org/10.3150/08-BEJ180 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Polarization of GRB Prompt Emission

We review the recent observational results of the gamma-ray linear polarization of Gamma-Ray Bursts (GRBs), and discuss some theoretical implications for the prompt emission mechanism and the magnetic composition of GRB jets. We also report a strict observational verification of CPT invariance in the photon sector as a result of the GRB polarization measurements.Comment: 13 pages, 5 figures, 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 45 in eConf Proceedings C130414

Rapidity Dependence of HBT radii based on a hydrodynamical model

We calculate two-pion correlation functions at finite rapidities based on a hydrodynamical model which does not assume explicit boost invariance along the collision axis. Extracting the HBT radii through $\chi^2$ fits in both Cartesian and Yano-Koonin-Podgoretski\u{\i} parametrizations, we compare them with the experimental results obtained by the PHOBOS. Based on the results, we discuss longitudinal expansion dynamics.Comment: 8 pages, 10 figures, talk given at II Workshop on Particle Correlation and Femtoscopy (WPCF 2006), Sep 9-11, Sao Paulo, Brazil. Revised version to be published in Braz.J.Phy

Cosmological models with the energy density of random fluctuations and the Hubble-constant problem

First the fluctuation energy is derived from the adiabatic random fluctuations due to the second-order perturbation theory, and the evolutionary relation for it is expressed in the form of rho_f = rho_f (rho), where rho and rho_f are the densities of ordinary dust and the fluctuation energy, respectively. The pressureless matter as a constituent of the universe at the later stage is assumed to consist of ordinary dust and the fluctuation energy. Next, cosmological models including the fluctuation energy as a kind of dark matter are derived using the above relation, and it is found that the Hubble parameter and the other model parameters in the derived models can be consistent with the recent observational values. Moreover, the perturbations of rho and rho_f are studied.Comment: 14 pages, 7 figure

Bounded Optimal Exploration in MDP

Within the framework of probably approximately correct Markov decision processes (PAC-MDP), much theoretical work has focused on methods to attain near optimality after a relatively long period of learning and exploration. However, practical concerns require the attainment of satisfactory behavior within a short period of time. In this paper, we relax the PAC-MDP conditions to reconcile theoretically driven exploration methods and practical needs. We propose simple algorithms for discrete and continuous state spaces, and illustrate the benefits of our proposed relaxation via theoretical analyses and numerical examples. Our algorithms also maintain anytime error bounds and average loss bounds. Our approach accommodates both Bayesian and non-Bayesian methods.Comment: In Proceedings of the 30th AAAI Conference on Artificial Intelligence (AAAI), 201