Quantum remote control: remotely and conclusively changing the overlap between two qubit states

Abstract

We propose a scheme for Alice to change remotely and conclusively the overlap between Bob’s two nonorthogonal qubit states with a finite probability of success. The remote nonunitary evolution of Bob’s primary system could be generated by performing a proper nonlocal unitary transformation on Bob’s primary system and Alice’s auxiliary system, followed by a local von Neumann projective measurement on Alice’s ancilla. The various desired inner product modifications between Bob’s primary states can be efficiently and fully controlled by Alice’s auxiliary states. We build a quantum network for implementing rapidly the remote nonunitary transformation, and thus provide a feasible physical means to realize the remote and controllable inner product modification. This scheme is feasible for current experimental technology.