Quantum teleportation with continuous measurements

TL;DR

This paper presents a quantum teleportation scheme using continuous measurements on a cavity field, demonstrating how past quantum state formalism can optimize fidelity in realistic, leaky quantum systems.

Contribution

It introduces a teleportation protocol relying on continuous measurements instead of projective Bell measurements, with analysis applicable to superconducting qubits and resonators.

Findings

Successful application of past quantum state formalism for measurement outcome estimation

Optimization of teleportation fidelity through continuous signal analysis

Highlighting the importance of measurement detail in non-ideal quantum systems

Abstract

We propose a scheme for quantum teleportation between two qubits, coupled sequentially to a cavity field. An implementation of the scheme is analyzed with superconducting qubits and a transmission line resonator, where measurements are restricted to continuous probing of the field leaking from the resonator rather than instantaneous projective Bell state measurement. We show that the past quantum state formalism [S. Gammelmark et al, Phys. Rev. 111, 160401] can be successfully applied to estimate what would have been the most likely Bell measurement outcome conditioned on our continuous signal record. This information determines which local operation on the target qubit yields the optimal teleportation fidelity. Our results emphasize the significance of applying a detailed analysis of quantum measurements in feed-forward protocols in non-ideal leaky quantum systems.