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 ${|\psi ⟩}^{\otimes n}$ through condensation, then subsequently controlled by varying the qubit-qubit interaction. An experimental implementation of quantum state discrimination, an important subroutine in quantum computation, with a toroidal Bose–Einstein condensate is proposed. The condensed bosons here are atoms, each in the same superposition of angular momenta 0 and $\hslash$, encoding a qubit. A nice feature of the protocol is that only a readout of individual quantized circulation states (not superpositions) is required.