Enhanced Quantum Estimation via Purification

Abstract

We analyze the estimation of a finite ensemble of quantum bits which have been sent through a depolarizing channel. Instead of using the depolarized qubits directly, we first apply a purification step and show that this improves the fidelity of subsequent quantum estimation. Even though we lose some qubits of our finite ensemble the information is concentrated in the remaining purified ones.

6 pages, including 3 figures

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Cited by in corpus (6)

• Optimal full estimation of qubit mixed states
• Local asymptotic normality for qubit states
• Optimal probabilistic cloning and purification of quantum states
• Experimental Purification of Single Qubits
• Optimal estimation of qubit states with continuous time measurements
• Quantum state identification of qutrits via a nonlinear protocol