Quenching the Chiral Magnetic Effect via the Gravitational Anomaly and Holography.

In the presence of a gravitational contribution to the chiral anomaly, the chiral magnetic effect induces an energy current proportional to the square of the temperature in equilibrium. In holography the thermal state corresponds to a black hole. We numerically study holographic quenches in which a planar shell of scalar matter falls into a black hole and raises its temperature.

Experimental signatures of the mixed axial-gravitational anomaly in the Weyl semimetal NbP.

The conservation laws, such as those of charge, energy and momentum, have a central role in physics. In some special cases, classical conservation laws are broken at the quantum level by quantum fluctuations, in which case the theory is said to have quantum anomalies. One of the most prominent examples is the chiral anomaly, which involves massless chiral fermions.

Odd Viscosity in the Quantum Critical Region of a Holographic Weyl Semimetal.

We study odd viscosity in a holographic model of a Weyl semimetal. The model is characterized by a quantum phase transition from a topological semimetal to a trivial semimetal state. Since the model is axisymmetric in three spatial dimensions there are two independent odd viscosities.

Quantum Phase Transition between a Topological and a Trivial Semimetal from Holography.

We present a holographic model of a topological Weyl semimetal. A key ingredient is a time-reversal breaking parameter and a mass deformation. Upon varying the ratio of mass to time-reversal breaking parameter the model undergoes a quantum phase transition from a topologically nontrivial semimetal to a trivial one.

Elastic Gauge Fields in Weyl Semimetals.

We show that, as happens in graphene, elastic deformations couple to the electronic degrees of freedom as pseudogauge fields in Weyl semimetals. We derive the form of the elastic gauge fields in a tight-binding model hosting Weyl nodes and see that this vector electron-phonon coupling is chiral, providing an example of axial gauge fields in three dimensions. As an example of the new response functions that arise associated with these elastic gauge fields, we derive a nonzero phonon Hall viscosity for the neutral system at zero temperature.

Gravitational anomaly and transport phenomena.

Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas.