4,913 research outputs found
Functional Renormalization for Chiral and U_A(1) Symmetries at Finite Temperature
We investigated the chiral symmetry and U_A(1) anomaly at finite temperature
by applying the functional renormalization group to the SU(3) linear sigma
model. Expanding the local potential around the classical fields, we derived
the flow equations for the renormalization parameters. In chiral limit, the
flow equation for the chiral condensate is decoupled from the others and can be
analytically solved. The Goldstone theorem is guaranteed in vacuum and at
finite temperature, and the two phase transitions for the chiral and U_A(1)
symmetry restoration happen at the same critical temperature. In general case
with explicit chiral symmetry breaking, the two symmetries are partially and
slowly restored, and the scalar and pseudoscalar meson masses are controlled by
the restoration in the limit of high temperature.Comment: 9 pages, 9figure
Complete and Consistent Chiral Transport from Wigner Function Formalism
Recently there has been significant interest in understanding the macroscopic
quantum transport in a many-body system of chiral fermions. A natural framework
for describing such a system which is generally out of equilibrium, is the
transport equation for its phase space distribution function. In this paper, we
obtain a complete solution of the covariant chiral transport for massless
fermions, by starting from the general Wigner function formalism and carrying
out a complete and consistent semiclassical expansion up to
order. In particular, we clarify certain subtle and
confusing issues surrounding the Lorentz non-invariance and frame dependence
associated with the 3D chiral kinetic theory. We prove that such frame
dependence is uniquely and completely fixed by an unambiguous definition of the
correction to the distribution function in each
reference frame
Advanced numerical modelling of caisson foundations in sand to investigate the failure envelope in the H-M-V space
International audienceThis paper focuses on the identification of the failure envelope of a caisson foundation in sand using an advanced critical state-based sand model (SIMSAND) and the Combined Lagrangian Smoothed Particle Hydrodynamics Method (CLSPH). The parameters of the SIMSAND constitutive model are first calibrated using triaxial tests on Baskarp sand. In order to validate the combined CLSPH-SIMSAND approach, a cone penetration test, model tests and a field test on a reduced scale caisson foundation are simulated. After full numerical validations with different scales from laboratory to in-situ conditions, a numerical parametrical study is then introduced considering different sand properties (density, friction angle, deformability, crushability) and caisson dimensions (soil-structure contact surface area, diameter-depth ratio) and complex combined loading paths to identify the failure envelope in the horizontal force (H), bending moment (M), vertical force (V) space. The influence of the caisson foundation contact surface area, aspect ratio and soil parameters are considered and quantified. Finally, an analytical formula is proposed for the 3D failure envelope in the H-M-V space
Bank Efficiency and Regional Economic Growth: Evidence from China
This paper examines for the first time the relationship between bank efficiency and regional economic growth in China with provincial data over 1995 - 2014. We find consistent and strong evidence that bank efficiency positively affects regional economic growth. Further, bank efficiency exerts a more pronounced impact on economic growth in inland provinces than coastal regions. The insignificant effect of the quantity of credit in our regressions suggests that a mere expansion of financial volume is not effective in promoting regional economic growth, whereas the improvement in the quality of financial intermediation plays an important role fostering provincial economic growth
Quark and Gluon Condensates in Isospin Matter
Applying the Hellmann-Feynman theorem to a charged pion gas, the quark and
gluon condensates at low isospin density are determined by precise pion
properties. At intermediate density around , from both the
estimation for the dilute pion gas and the calculation with Nambu--Jona-Lasinio
model, the quark condensate is strongly and monotonously suppressed, while the
gluon condensate is enhanced and can be larger than its vacuum value. This
unusual behavior of the gluon condensate is universal for Bose condensed matter
of mesons. Our results can be tested by lattice calculations at finite isospin
density.Comment: 4 pages, 2 figures. Published version in PR
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