12,131 research outputs found
A Note on Complex-Hyperbolic Kleinian Groups
Let Γ be a discrete group of isometries acting on the complex hyperbolic n-space HCn. In this note, we prove that if Γ is convex-cocompact, torsion-free, and the critical exponent δ(Γ) is strictly lesser than 2, then the complex manifold HCn/Γ is Stein. We also discuss several related conjectures
Mean field baryon magnetic moments and sumrules
New developments have spurred interest in magnetic moments (-s) of
baryons. The measurement of some of the decuplet -s and the findings of
new sumrules from various methods are partly responsible for this renewed
interest. Our model, inspired by large colour approximation, is a relativistic
self consistent mean field description with a modified Richardson potential and
is used to describe the -s and masses of all baryons with up (u), down (d)
and strange (s) quarks. We have also checked the validity of the Franklin
sumrule (referred to as CGSR in the literature) and sumrules of Luty,
March-Russell and White. We found that our result for sumrules matches better
with experiment than the non-relativistic quark model prediction. We have also
seen that quark magnetic moments depend on the baryon in which they belong
while the naive quark model expects them to be constant.Comment: 7 pages, no figure, uses epl.cl
Strange stars at finite temperature
We calculate strange star properties, using large N_c approximation with
built-in chiral symmetry restoration (CSM). We used a relativistic Hartree Fock
mean field approximation method, using a modified Richardson potential with two
scale parameters \Lambda and \Lambda^\prime, to find a new set of equation of
states for strange quark matter. We take the effect of temperature (T) on gluon
mass, in addition to the usual density dependence, and find that the transition
T from hadronic matter to strange matter is 80 MeV. Therefore formation of
strange stars may be the only signal for formation of QGP with asymptotic
freedom and CSM.Comment: To be published in the proceedings of The Third 21COE Symposium, held
at Department of Physics, Waseda University, Tokyo, Japan, September 1-3,
200
An Equilibrium Model of Health Insurance Provision and Wage Determination
We investigate the e_ect of employer-provided health insurance on job mobility rates and economic welfare. In particular, we develop and estimate an equilibrium model of wage and health insurance determination that yields implications that are empirically observed. Namely, not all jobs provide health insurance and jobs with insurance pay higher wages than those without insurance. Using data from the 1990 to 1993 panels of the Survey of Income and Program Participation, we find that jobs that do provide health insurance last almost five times longer than jobs that do not. While this implies that the mobility rate for jobs without insurance is significantly higher than the mobility rate for jobs with insurance, this di_erence is welfare enhancing since jobs with health insurance are more productive jobs. Furthermore, simulations reveal that decreasing the health insurance premium paid by employers increases the steady state health insurance coverage rate, decreases the unemployment rate, but may or may not lead to productivity gains in the economy.HEALTH INSURANCE; EQUILIBRIUM MODELS; WAGE BARGAINING; JOB MOBILITY
Maximum mass of a cold compact star
We calculate the maximum mass of the class of compact stars described by
Vaidya-Tikekar \cite{VT01} model. The model permits a simple method of
systematically fixing bounds on the maximum possible mass of cold compact stars
with a given value of radius or central density or surface density. The
relevant equations of state are also determined. Although simple, the model is
capable of describing the general features of the recently observed very
compact stars. For the calculation, no prior knowledge of the equation of state
(EOS) is required. This is in contrast to the earlier calculations for maximum
mass which were done by choosing first the relevant EOSs and using those to
solve the TOV equation with appropriate boundary conditions. The bounds
obtained by us are comparable and, in some cases, more restrictive than the
earlier results.Comment: 18 pages including 4 *.eps figures. Submitted for publicatio
Geometric Prequantization of the Moduli Space of the Vortex equations on a Riemann surface
The moduli space of solutions to the vortex equations on a Riemann surface
are well known to have a symplectic (in fact K\"{a}hler) structure. We show
this symplectic structure explictly and proceed to show a family of symplectic
(in fact, K\"{a}hler) structures on the moduli space,
parametrised by , a section of a line bundle on the Riemann surface.
Next we show that corresponding to these there is a family of prequantum line
bundles on the moduli space whose curvature is
proportional to the symplectic forms .Comment: 8 page
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