Optical-Nanomechanical Quantum Interface Quantum Interface

A quantum interface, which can interconvert stationary qubits and flying qubits, is the key component of a quantum computer. If every node with a quantum interface can be combined, we can realize operations such as quantum state transfer, entanglement swapping and deterministic entanglement creation in a quantum work.The very quantum interface we have studied is an optical—mechanical quantum interface, which includes a fiber、a microtoroidal cavity and a nanomechanical resonator. In this interface, a nanomechanical qubit play the role of a stationary qubit. Here we can deal with the match between the pulse shape of the driving pulse and the waveform of the incoming single photon, in case the single photon qubit can be reflected by the cavity, which previous approaches have not solved.All of our work consists of theoretical analysis and numerical simulation. In theoretical analysis, we first fabricated the Hamilton of the system, then solved the Schrodinger equation in the interaction picture, as a result of which, we had known how the amplitudes of the OM system evolved. Furthermore, we attained the equations which describe the operations such as transferring and distributing quantum entanglement between two remote nanomechanical qubits. Next, we analyzed the source of decoherence, and then did numerical simulations in the realistic conditions. The situations we dealt with included a single photon generation and absorption, the entanglement between the mechanical and photon qubits and the process of transferring an unknown state. The results show that near unity operation fidelities may be obtainable under experimental circumstances. Both the theoretical analysis and the numerial simulation prove that it is valuable for us to study this quantum interface, and we can expect some applications in the future.