Bose condensates at high angular momenta

Abstract

We exploit the analogy with the Quantum Hall (QH) system to study weakly interacting bosons in a harmonic trap. For a $δ$-function interaction potential the ``yrast'' states with $L\ge N(N-1)$ are degenerate, and we show how this can be understood in terms of Haldane exclusion statistics. We present spectra for 4 and 8 particles obtained by numerical and algebraic methods, and demonstrate how a more general hard-core potential lifts the degeneracies on the yrast line. The exact wavefunctions for N=4 are compared with trial states constructed from composite fermions (CF), and the possibility of using CF-states to study the low L region at high N is discussed.