Scalable entanglement of remote material qubits produced by single photons via a no-energy-exchange process
Gang Li, Pengfei Zhang, Tiancai Zhang
We propose a proposal to generate scalable entanglement of remote material qubits via no-energy-exchange interactions with single photons. A strongly-coupled cavity quantum electrodynamics (CQED) system is arranged as a single-photon-level quantum router, which routes incoming photons to different outports based on the state of the involved material qubit. Two of the routers with qubits in their maximum superposition state are coupled together with a Mach-Zehnder-interferometer-like configuration. As a single photon transits through the system, we find the maximum entangled state between qubits is produced by finding a photon in the output mode. Remarkably, there is no energy exchanged between material qubits and photons. This ensures the possibility of purifying entangled states by using more photons in a physical situation, where loss and imperfections are inevitable. It also guarantees scalability in order to produce entanglement among multiple qubits without inducing incoherence caused by energy exchange. We analyzed the fidelity and probability of success for the proposed strongly-coupled CQED system. The expected maximum fidelity could reach over 0.9997 using only two photons in a technologically-feasible experiment. We also analyzed the scalability by providing examples for the generation of N-qubit entanglement and 3-qubit Greenberger-Horne-Zeilinger states based on the proposed technique. Our proposed method could be applied to create entanglement between multiple-node systems in a quantum network, or to generate special entangled state between remote material qubits, thereby testing the fundamentals of quantum mechanics.
•Aug 12, 2016•0 citations