Equation of State of an Anyon Gas in a Strong Magnetic Field

The statistical mechanics of an anyon gas in a magnetic field is addressed. An harmonic regulator is used to define a proper thermodynamic limit. When the magnetic field is sufficiently strong, only exact $N$-anyon groundstates, where anyons occupy the lowest Landau level, contribute to the equation of state. Particular attention is paid to the interval of definition of the statistical parameter $\alpha\in[-1,0]$ where a gap exists. Interestingly enough, one finds that at the critical filling $\nu=-{1/\alpha}$ where the pressure diverges, the external magnetic field is entirely screened by the flux tubes carried by the anyons.Comment: 14 pages, PACS numbers: 03.65.-w, 05.30.-d, 05.70.Ce, IPNO/TH 93-16 (MAY 1993), e-mail: OUVRY@FRCPN1