scholarly journals Covariant chiral kinetic equation in non-Abelian gauge field from “covariant gradient expansion”

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Xiao-Li Luo ◽  
Jian-Hua Gao

Abstract We derive the chiral kinetic equation in 8 dimensional phase space in non- Abelian SU(N) gauge field within the Wigner function formalism. By using the “covariant gradient expansion”, we disentangle the Wigner equations in four-vector space up to the first order and find that only the time-like component of the chiral Wigner function is independent while other components can be explicit derivative. After further decomposing the Wigner function or equations in color space, we present the non-Abelian covariant chiral kinetic equation for the color singlet and multiplet phase-space distribution functions. These phase-space distribution functions have non-trivial Lorentz transformation rules when we define them in different reference frames. The chiral anomaly from non-Abelian gauge field arises naturally from the Berry monopole in Euclidian momentum space in the vacuum or Dirac sea contribution. The anomalous currents as non-Abelian counterparts of chiral magnetic effect and chiral vortical effect have also been derived from the non-Abelian chiral kinetic equation.

2016 ◽  
Vol 40 ◽  
pp. 1660055
Author(s):  
Asmita Mukherjee ◽  
Sreeraj Nair ◽  
Vikash Kumar Ojha

Wigner distribution functions are the quantum analogue of the classical phase space distribution and being quantum implies that they are not genuine phase space distribution and thus lack any probabilistic interpretation. Nevertheless, Wigner distributions are still interesting since they can be related to both generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs) under some limit. We study the Wigner distribution of quarks and also the orbital angular momentum (OAM) of quarks in the dressed quark model.


1987 ◽  
Vol 120 (4) ◽  
pp. 161-164 ◽  
Author(s):  
R. Jagannathan ◽  
R. Simon ◽  
E.C.G. Sudarshan ◽  
R. Vasudevan

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
Pierfrancesco Di Cintio ◽  
L. Ciotti ◽  
C. Nipoti

We continue the study of collisionless systems governed by additive$r^{-{\it\alpha}}$interparticle forces by focusing on the influence of the force exponent${\it\alpha}$on radial orbital anisotropy. In this preparatory work, we construct the radially anisotropic Osipkov–Merritt phase-space distribution functions for self-consistent spherical Hernquist models with$r^{-{\it\alpha}}$forces and$1\leqslant {\it\alpha}<3$. The resulting systems are isotropic at the centre and increasingly dominated by radial orbits at radii larger than the anisotropy radius$r_{a}$. For radially anisotropic models we determine the minimum value of the anisotropy radius$r_{ac}$as a function of${\it\alpha}$for phase-space consistency (such that the phase-space distribution function is nowhere negative for$r_{a}\geqslant r_{ac}$). We find that$r_{ac}$decreases for decreasing${\it\alpha}$, and that the amount of kinetic energy that can be stored in the radial direction relative to that stored in the tangential directions for marginally consistent models increases for decreasing${\it\alpha}$. In particular, we find that isotropic systems are consistent in the explored range of${\it\alpha}$. By means of direct$N$-body simulations, we finally verify that the isotropic systems are also stable.


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