Weak measurement feedback and Zeno pinning for remote entanglement generation and stabilization in superconducting qubits

Superconducting qubits are one of the most promising qubit technologies due to their balance of addressability (ability to couple to their environment) and coherence (ability to isolate from the environment). Weak measurement utilizes weak probes of a readout resonator coupled to the qubit in order to gain small amounts of information about the qubit state, leading to diffusive trajectories in Hilbert space. This is a valuable tool for state preparation and control because it allows for unitary feedback as the measurement takes place.

We present simulations of a weak measurement feedback protocol for remotely generating and stabilizing entanglement between two qubits. In particular, we simulate the role of unwanted coupling to two-level fluctuators (creating a 1/f dephasing noise spectrum), and methods for decoupling the qubit from these fluctuators during the feedback process. We explore the possibility of using strong measurement to stabilize entanglement with the quantum Zeno effect. We also highlight the role of the noise spectrum (Markovian vs. non-Markovian) in the stabilization efficacy.