Two definitions of fractional statistics in condensed matter physics

Abstract

I discuss recent developments in the application of fractional statistics to condensed matter physics. I emphasize Haldane’s recent and novel definition of fractional statistics, partly in order to discuss some very recent work involving this concept, and partly in order to highlight a promising direction for future work. The applicability of both the conventional definition (in terms of exchange phase) and Haldane’s ‘‘fractional exclusion principle’’ are examined for the charged excitations (quasiparticles) of the fractional quantum Hall effect (FQHE). Subsequently, the viability of ‘‘anyon superconductivity’’ (which is defined solely in terms of the former definition) is critically examined in the light of recent experiments. The possible utility of Haldane’s definition for the HTSC is briefly discussed.