Dr. Rajesh Narajanan, INT

Titel: Griffiths Phase in Unconventional Quantum Hall Effect.

Abstract:

The Integer Quantum Hall Effect (IQHE) is one of the most important discoveries in the field of condensed matter physics. Its most striking manifestation is the quantization of the Hall conductance in units of $e^2/h$. In the recent past there has been a great deal of interest in investigating analogs of the IQHE. Thus, we explore the possibility of finding systems wherein Hall coefficients for spin or heat transport can exhibit plateaus in either the spin or thermal conductivity.

The former effect is called the Spin Quantum Hall Effect (SQHE), The former effect is called the Spin Quantum Hall Effect (SQHE), and the latter the Thermal Quantum Hall Effect (TQHE).

The main focus of the talk will be on the TQHE. The TQHE finds a natural realization in two dimensional disordered superconductor with $p$-wave pairing, or in the $\nu =5/2$ state of the fractional quantum Hall effect.

We will show that the TQHE shows many interesting and peculiar properties as compared to their IQHE or SQHE counterparts. We will conclude with a brief description of non-Abelian statistics that one encounters in the $\nu = 5/2$ state. We will attempt to motivate how such a state may be used for quantum computing.