Seminar by Bertrand Halperin – University of Copenhagen

Seminar by Bertrand Halperin

The Search for Majorana Entropy in the f=5/2 Fractional Quantized Hall State

If a two-dimensional electron system lying in the regime of the
5/2 fractional quantized Hall state contains a finite number of localized,
well isolated quasiparticles, and if the state falls in the universality
class of  the Pfaffian or anti-Pfaffian wave function, then the system
should have an anomalous  residual entropy of (1/2) log 2 per
quasiparticle, arising from the zero-energy Majorana degrees of freedom.
The talk will review some of the schemes that have been proposed in the
past for observing this entropy, which include macroscopic thermodynamic
measurements and indirect methods, which look for effects of the Majorana
entropy on thermo-electric transport measurements at low temperatures.  We
shall also discuss a recent proposal to look for temperature-dependent
shifts in the charging spectrum near an individual local minimum or
maximum of the spatially varying electrostatic potential, which can be
measured with a scanned single-electron-transistor device. [1]

1.  G. Ben-Schach, C. R. Laumann, I. Neder, A. Yacoby, and B. I. Halperin,
Phys. Rev. Lett. 110, 106805 (2013).