23,548 research outputs found
Constantin and Iyer's representation formula for the Navier--Stokes equations on manifolds
The purpose of this paper is to establish a probabilistic representation
formula for the Navier--Stokes equations on compact Riemannian manifolds. Such
a formula has been provided by Constantin and Iyer in the flat case of or of . On a Riemannian manifold, however, there are several
different choices of Laplacian operators acting on vector fields. In this
paper, we shall use the de Rham--Hodge Laplacian operator which seems more
relevant to the probabilistic setting, and adopt Elworthy--Le Jan--Li's idea to
decompose it as a sum of the square of Lie derivatives.Comment: 26 pages. We add Section 4 discussing the Killing vector fields on
Riemannian symmetric spaces which satisfy the conditions in Section
Method for Extracting the Glueball Wave Function
We describe a nonperturbative method for calculating the QCD vacuum and
glueball wave functions, based on an eigenvalue equation approach to
Hamiltonian lattice gauge theory. Therefore, one can obtain more physical
information than the conventional simulation methods. For simplicity, we take
the 2+1 dimensional U(1) model as an example. The generalization of this method
to 3+1 dimensional QCD is straightforward.Comment: 3 pages, Latex. Presented at Lattice 97: 15th International Symposium
on Lattice Field Theory, Edinburgh, Scotland, 22-26 Jul 1997, to appear in
Nucl. Phys. B(Proc. Suppl.
QCD at Finite temperature and density with staggered and Wilson quarks
One of the most challenging issues in particle physics is to study QCD in
extreme conditions. Precise determination of the QCD phase diagram on
temperature and chemical potential plane will provide valuable
information for quark-gluon plasma (QGP) and neutron star physics. We present
results for phase structure on the plane for lattice QCD with Wilson
fermions from strong coupling Hamiltonian analysis and Kogut-Susskind Fermions
from Lagrangian Monte Carlo simulations at intermediate coupling.Comment: Lattice 2004 (nonzero
The Effects of Outdoor Air Pollutants on the Costs of Stroke Hospitalizations in China
Stroke, the most frequent cause of severe disability and the second cause of death among adults in the world, brings tremendous mental and economic burden to patients and their families. Emerging evidence indicates that the air pollution mixture contributes to strokes. Knowing the relationship between the air pollution and the hospital costs of stroke can help us predict the costs due to air pollution, provide grounds for the allocation of medical insurance funds, and provide better working arrangements for CDC. However, few studies have examined this connection. We used time series analysis with a generalized additive model to estimate the associations between ambient air pollutions and hospital costs between the period of 2015–2017. We were surprised to find that although same-day air pollutions were positively associated with stroke mortality hospital costs were found to have a negatively association. Suggestive evidence of an association between fine particles and the costs of stroke were found: more serious air pollution increases the risk of stroke, but has a dampening effect on hospital costs. This study is the first step in optimizing medical resources, which is essential for policy making, service planning, and cost-effectiveness analysis of new therapeutic strategies
Hamiltonian lattice quantum chromodynamics at finite density with Wilson fermions
Quantum chromodynamics (QCD) at sufficiently high density is expected to
undergo a chiral phase transition. Understanding such a transition is of
particular importance for neutron star or quark star physics. In Lagrangian
SU(3) lattice gauge theory, the standard approach breaks down at large chemical
potential , due to the complex action problem. The Hamiltonian formulation
of lattice QCD doesn't encounter such a problem. In a previous work, we
developed a Hamiltonian approach at finite chemical potential and
obtained reasonable results in the strong coupling regime. In this paper, we
extend the previous work to Wilson fermions. We study the chiral behavior and
calculate the vacuum energy, chiral condensate and quark number density, as
well as the masses of light hadrons. There is a first order chiral phase
transition at zero temperature.Comment: 23 pages. Version accepted for publication in Physical Review
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