Null Values and Quantum State Discrimination

Abstract

We present a measurement protocol for discriminating between two different quantum states of a qubit with high fidelity. The protocol, called null value, is comprised of a projective measurement performed on the system with a small probability (also known as partial-collapse), followed by a tuned postselection. We report on an optical experimental implementation of the scheme. We show that our protocol leads to an amplified signal-to-noise ratio (as compared with a straightforward strong measurement) when discerning between the two quantum states.

11 pages, 6 figures, 5 appendices

References in corpus (5)

• Ultrasensitive Beam Deflection Measurement via Interferometric Weak Value Amplification
• Optimizing the Signal to Noise Ratio of a Beam Deflection Measurement with Interferometric Weak Values
• Measurement efficiency and n-shot read out of spin qubits
• Coherence of a Josephson phase qubit under partial-collapse measurement
• Null weak values in multi-level systems

Cited by in corpus (2)

• Heisenberg scaling with weak measurement: A quantum state discrimination point of view
• On the Power of Weak Measurements in Separating Quantum States