248 research outputs found
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
Calculating multiloop integrals using dimensional recurrence relation and D-analyticity
We review the method of the calculation of multiloop integrals recently
suggested in Ref.[Lee2010]. A simple method of derivation of the dimensional
recurrence relation suitable for automatization is given. Some new analytic
results are given.Comment: Talk presented at 10th DESY Workshop on Elementary Particle Theory:
Loops and Legs in Quantum Field Theory, Worlitz, Germany, 25-30 April 201
Chiral Vortical Effect in Fermi Liquid
In this note we consider non-relativistic rotating fermi liquid in the
presence of Berry curvature. The behavior of the system is then almost the same
as in external magnetic field. We argue that there appears an analogue of
chiral vortical effect in the liquid if Berry curvature has a non-vanishing
flux through sheets of Fermi surfaces and chemical potentials are different. We
also claim that quantum anomalies in condensed matter context provide a
theoretical and experimental testing ground for the origin of chiral effects,
their carriers etc.Comment: minor corrections, additional citation
On the Higher-Spin Spectrum in Large N Chern-Simons Vector Models
Chern-Simons gauge theories coupled to massless fundamental scalars or
fermions define interesting non-supersymmetric 3d CFTs that possess approximate
higher-spin symmetries at large N. In this paper, we compute the scaling
dimensions of the higher-spin operators in these models, to leading order in
the 1/N expansion and exactly in the 't Hooft coupling. We obtain these results
in two independent ways: by using conformal symmetry and the classical
equations of motion to fix the structure of the current non-conservation, and
by a direct Feynman diagram calculation. The full dependence on the 't Hooft
coupling can be restored by using results that follow from the weakly broken
higher-spin symmetry. This analysis also allows us to obtain some explicit
results for the non-conserved, parity-breaking structures that appear in planar
three-point functions of the higher-spin operators. At large spin, we find that
the anomalous dimensions grow logarithmically with the spin, in agreement with
general expectations. This logarithmic behavior disappears in the strong
coupling limit, where the anomalous dimensions turn into those of the critical
O(N) or Gross-Neveu models, in agreement with the conjectured 3d bosonization
duality.Comment: 52 pages, 7 figures. v3: Minor correction
- …