197 research outputs found
Chiral Vortical Effect in Superfluid
We consider rotating superfluid pionic liquid, with superfluidity being
induced by isospin chemical potential. The rotation is known to result in a
chiral current flowing along the axis of the rotation. We argue that in case of
superfluidity the chiral current is realized on fermionic zero modes
propagating along vortices. The current evaluated in this way differs by a
factor of two from the standard one. The reason is that the chiral charge is
carried by zero modes which propagate with speed of light, and thus the liquid
cannot be described by a single (local) velocity, like it is assumed in
standard derivations.Comment: 10 pages. To be published in PRD. Minor changes added; typos fixe
Anomalous Transport and Generalized Axial Charge
In this paper we continue studying the modification of the axial charge in
chiral media by macroscopic helicities. Recently it was shown that magnetic
reconnections result in a persistent current of zero mode along flux tubes.
Here we argue that in general a change in the helical part of the generalized
axial charge results in the same phenomenon. Thus one may say that there is a
novel realization of chiral effects requiring no initial chiral asymmetry. The
transfer of flow helicity to zero modes is analyzed in a toy model based on a
vortex reconnection in a chiral superfluid. Then, we discuss the balance
between the two competing processes effect of reconnections and the chiral
instability on the example of magnetic helicity. We argue that in the general
case there is a possibility for the distribution of the axial charge between
the magnetic and fermionic forms at the end of the instability.Comment: 19 pages, version accepted in PR
Chiral Magnetic Effect in Hydrodynamic Approximation
We review derivations of the chiral magnetic effect (ChME) in hydrodynamic
approximation. The reader is assumed to be familiar with the basics of the
effect. The main challenge now is to account for the strong interactions
between the constituents of the fluid. The main result is that the ChME is not
renormalized: in the hydrodynamic approximation it remains the same as for
non-interacting chiral fermions moving in an external magnetic field. The key
ingredients in the proof are general laws of thermodynamics and the
Adler-Bardeen theorem for the chiral anomaly in external electromagnetic
fields. The chiral magnetic effect in hydrodynamics represents a macroscopic
manifestation of a quantum phenomenon (chiral anomaly). Moreover, one can argue
that the current induced by the magnetic field is dissipation free and talk
about a kind of "chiral superconductivity". More precise description is a
ballistic transport along magnetic field taking place in equilibrium and in
absence of a driving force. The basic limitation is exact chiral limit while
the temperature--excitingly enough- does not seemingly matter. What is still
lacking, is a detailed quantum microscopic picture for the ChME in
hydrodynamics. Probably, the chiral currents propagate through
lower-dimensional defects, like vortices in superfluid. In case of superfluid,
the prediction for the chiral magnetic effect remains unmodified although the
emerging dynamical picture differs from the standard one.Comment: 35 pages, prepared for a volume of the Springer Lecture Notes in
Physics "Strongly interacting matter in magnetic fields" edited by D.
Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye
Chiral vortical effect generated by chiral anomaly in vortex-skyrmions
We discuss the type of the general macroscopic parity-violating effects, when
there is the current along the vortex, which is concentrated in the vortex
core. We consider vortices in superfluids, which contain the Weyl points. In
the vortex core the positions of the Weyl points form the skyrmion structure.
We show that the mass current concentrated in such a core is provided by the
spectral flow through the Weyl points according to the Adler-Bell-Jackiw
equation for chiral anomaly.Comment: 5 pages, 2 figures, version accepted in JETP Letter
Triangle anomaly in Weyl semi-metals
Weyl semimetals possess massless chiral quasi-particles, and are thus
affected by the triangle anomalies. We discuss the features of the chiral
magnetic and chiral vortical effects specific to Weyl semimetals, and then
propose three novel phenomena caused by the triangle anomalies in this
material: 1) anomaly cooling; 2) charge transport by soliton waves as described
by the Burgers' equation, and 3) the shift of the BKT phase transition of
superfluid vortices coupled to Weyl fermions. In addition, we establish the
conditions under which the chiral magnetic current exists in real materials.Comment: v3. Improved figures, minor changes in the text, 24 pages, 3 figure
An anomalous hydrodynamics for chiral superfluid
Starting from low energy effective chiral Lagrangian with gauged Wess-Zumino
Witten term, we have derived a hydrodynamic theory for chiral superfluid. It is
a non-abelian hydrodynamics at zero temperature with only superfluid
components. With an external electromagnetic field and baryonic and axial
baryonic chemical potentials turned on, we are able to identify analogs of
various anomaly induced term in normal hydrodynamics, including chiral vortical
effect, chiral magnetic effect and chiral electric effect. As an example, we
solved the hydrodynamic equations for the ground state and observed the chiral
magnetic effect and chiral separation in the confined phase.Comment: 21 page
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