Protocol for nonlinear state discrimination in rotating condensate

Nonlinear mean field dynamics enables quantum information processing operations that are impossible in linear one-particle quantum mechanics. In this approach, a register of bosonic qubits (such as neutral atoms or polaritons) is initialized into a symmetric product state through condensation, then subsequently controlled by varying the qubit-qubit interaction. We propose an experimental implementation of quantum state discrimination, an important subroutine in quantum computation, with a toroidal Bose-Einstein condensate. The condensed bosons here are atoms, each in the same superposition of angular momenta 0 and 1, encoding a qubit. A nice feature of the protocol is that only readout of individual quantized circulation states (not superpositions) is required.