Spontaneous Collapse by Entanglement Suppression

A modified Schrödinger equation having an added nonlinear term, which gives rise to disentanglement, has been recently proposed. The process of quantum measurement is explored for the case of a pair of coupled spins. It is found that the deterministic time evolution generated by the modified Schrödinger equation mimics the process of wavefunction collapse. Added noise gives rise to stochasticity in the measurement process. Conflict with both principles of causality and separability can be avoided by postulating that the nonlinear term is active only during the time when subsystems interact. Moreover, in the absence of entanglement, all predictions of standard quantum mechanics are unaffected by the added nonlinear term.