Two Coupled Harmonic Oscillators on Non-commutative Plane
Jellal, A, El Hassan El Kinani, Schreiber, M
Abstract
We investigate a system of two coupled harmonic oscillators on the non-commutative plane \\RR^2_{\\theta} by requiring that the spatial coordinates do not commute. We show that the system can be diagonalized by a suitable transformation, i.e. a rotation with a mixing angle \\alpha. The obtained eigenstates as well as the eigenvalues depend on the non-commutativity parameter \\theta. Focusing on the ground state wave function before the transformation, we calculate the density matrix \\rho_0(\\theta) and find that its traces {\\rm Tr}(\\rho_{0}(\\theta)) and {\\rm Tr}(\\rho_0^2(\\theta)) are not affected by the non-commutativity. Evaluating the Wigner function on \\RR^2_{\\theta} confirms this. The uncertainty relation is explicitly determined and found to depend on \\theta. For small values of \\theta, the relation is shifted by a \\theta^2 term, which can be interpreted as a quantum correction. The calculated entropy does not change with respect to the normal case. We consider the limits \\alpha=1 and \\alpha={\\pi\\over 2}. In first case, by identifying \\theta to the squared magnetic length, one can recover basic features of the Hall system.