The remote implementation of all possible generalized quantum measurement on single atomic qubit in a quantum network

To implement generalized quantum measurement (GQM) one has to extendthe original Hilbert space. Generally speaking, the additionaldimensions of the ancilla space increase as the number of theoperators of the GQM n increases. This paper presents a scheme fordeterministically implementing all possible n-operator GQMs on asingle atomic qubit by using only one 2-dimensional ancillary atomicqubit repeatedly, which remarkably reduces the complexity of therealistic physical system. Here the qubit is encoded in the internal statesof an atom trapped in an optical cavity and single-photon pulses areemployed to provide the interaction between qubits. It shows thatthe scheme can be performed remotely, and thus it is suitable forimplementing GQM in a quantum network. What is more, the number of thetotal ancilla dimensions in our scheme achieves the theoretic lowbound.