44,473 research outputs found

### QCD color interactions between two quarks

We study the QCD color interactions between static two heavy quarks at zero
temperature in a quenched SU(3) lattice gauge simulation: in addition to the
standard singlet $q\bar{q}$ potentials, we calculate octet $q\bar{q}$
potentials, symmetric and antisymmetric $qq$ potentials. It is shown that the
antisymmetric $qq$ channel behaves as a linearly rising potential at large
quark separations. We further find that the $q\bar{q}$ octet and $qq$ symmetric
channels have the complex dependence on the distance; at short distances they
are repulsive forces, while at large distances, they show linearly rising
feature. Ratio of string tensions between $q\bar{q}$ singlet and $qq$
antisymmetric potentials is described in terms of the Casimir factor

### Gluon Propagators and Confinement

We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at
beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16
(deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to
avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon
propagators show quite different behavior from those of massless gauge fields:
(1) In the confinement phase, G(t) shows massless behavior at small and large
t, while around 5<t<15 it behaves as massive particle, and (2) effective mass
observed in G(z) becomes larger as z increases. (3) In the deconfinement phase,
G(z) shows also massive behavior but effective mass is less than in the
confinement case. In all cases, slope masses are increasing functions of t or
z, which can not be understood as addtional physical poles.Comment: 6 pages in Postscrip

### A Case Report of Folie\u27a Deux: Husband-and-Wife

Shared paranoid disorder is a relatively rare psychiatric disorder in which paranoid delusions are transferred from one individual to one or more other susceptible person(s) in close association. Folie a deux describes a shared paranoid disorder involving two people and is characterized by a complex dependant relationship between the involved individuals. Provided there is no additional underlying psychopathology, there is a good prognosis for the submissive partner. Here we present a case report and discussion off folie a deux involving a husband and wife. Although folie a deux is a relatively uncommon disorder, it is important to recognize such cases due to the potential for recovery in the submissive partner

### Determining the Equation of State of the Expanding Universe Using a New Independent Variable

To determine the equation of state of the universe, we propose to use a new
independent variable $R\equiv (H_0/c)(d_L(z)/(1+z))$, where $H_0$ and $d_L(z)$
are the present Hubble parameter and the luminosity distance, respectively. For
the flat universe suggested from the observation of the anisotropy of cosmic
microwave background, the density and the pressure are expressed as
$\rho/\rho_0=4(df/dR)^2/f^6$ and $p/\rho_0=-4/3(d^2f/dR^2)/f^5$ where $\rho_0$
is the present density and $f(R)=1/\sqrt{1+z(R)}$. In $(R, f)$ plane the sign
as well as the strength of the pressure is in proportion to the curvature of
the curve $f(R)$. We propose to adopt a Pade-like expression of
$f(R)=1/\sqrt{u}$ with $u\equiv 1+\sum\limits_{n=1}^{N}u_nR^n$. For flat
$\Lambda$ model the expansion up to N=7 has at most an error $< 0.2%$ for $z <
1.7$ and any value of $\Lambda$. We also propose a general method to determine
the equation of state of the universe which has $N-1$ free parameters. If the
number of parameters are smaller than $N-1$, there is a consistency check of
the equation of state so that we may confirm or refute each model.Comment: 12 pages, to be published in the Astrophysical Journa

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