  Parity measurement is a key step in many entanglement generation and quantum
error correction schemes. We propose a protocol for non-destructive parity
measurement of two remote qubits, i.e., macroscopically separated qubits with
no direct interaction. The qubits are instead dispersively coupled to separate
resonators that radiate to shared photodetectors. The scheme is deterministic
in the sense that there is no fundamental bound on the success probability.
Compared to previous proposals, our protocol addresses the scenario where
number resolving photodetectors are available but the qubit-resonator coupling
is time-independent and only dispersive.

Quantum Physics