Anomalous hydrodynamics

Abstract

Our goal is to examine the role of anomalies in the hydrodynamic regime of field theories. We employ methods based on gauge/gravity duality to examine R-charge anomalies in the hydrodynamic regime of strongly t'Hooft coupled, large N , N = 4 Super Yang-Mills. We use a single particle spectrum treatment based on the familiar "level-crossing" picture of chiral anomalies to investigate thermalized massless QED. In each case we work in the presence of a homogeneous background magnetic field, and find the same result. Regardless of whether a particular current is anomalously non-conserved or not, as long as it participates in an anomalous 3-pt. correlator, its constitutive relation receives a new term: j a ∝ −d abc B b ρ c . This agrees with results found by Alekseev et.al. for QED. We include a general, symmetry based argument for the presence of such terms, and use linear response theory to determine their coefficients in a model with anomalous global charges. This last method, we apply to briefly examine baryon transport in chiral QCD in a strong magnetic field.

Axial Current Generation from Electric Field: Chiral Electric Separation Effect

“…We therefore see that its origin is not from the axial anomaly but from the conduction in a chiral manybody environment, and the CESE is different in nature from recently discussed axial current generation via anomaly in certain superfluid systems [34][35][36]. Note also that the relevant time scale, e.g., $1=ðeÞ should be long enough to justify treating A as a slowly varying external parameter [2,8].…”

Anomalous transport of Weyl fermions in Weyl semimetals

“…They have been found also via lattice QCD [48][49][50][51][52] and via holographic methods [21,24,25,38,[53][54][55][56][57][58].…”

“…More precisely a magnetic field induces a current via the chiral magnetic effect (CME) and a vortex or rotation of the fluid or gas of chiral fermions also induces a current via the chiral vortical effect (CVE) [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] (see also the recent reviews [33][34][35][36][37][38][39][40][41] ) Generalizations to arbitrary dimensions have been discussed in [42]. The hydrodynamic approach has been generalized in [43,44].…”

Topology, Magnetic Field, and Strongly Interacting Matter

“…Anomalous hydrodynamics possesses a novel gapless collective excitation-the chiral magnetic wave (74,75). It is analogous to sound, but in a strong magnetic field it propagates along the direction of the field with the velocity of light (74).…”