Quantum State Discrimination Circuits Inspired by Deutschian Closed Timelike Curves

Abstract

It is known that a party with access to a Deutschian closed timelike curve (D-CTC) can perfectly distinguish multiple non-orthogonal quantum states. In this paper, we propose a practical method for discriminating multiple non-orthogonal states, by using a previously known quantum circuit designed to simulate D-CTCs. This method relies on multiple copies of an input state, multiple iterations of the circuit, and a fixed set of unitary operations. We first characterize the performance of this circuit and study its asymptotic behavior. We also show how it can be equivalently recast as a local, adaptive circuit that may be implemented simply in an experiment. Finally, we prove that our state discrimination strategy achieves the multiple Chernoff bound when discriminating an arbitrary set of pure qubit states.

arXiv commentv2: 13 pages, 3 figures, accepted for publication in Physical Review A

References in corpus (20)

• The quantum mechanics of time travel through post-selected teleportation
• Minimum-error discrimination between three mirror-symmetric states
• Multiple copy 2-state discrimination with individual measurements
• Can closed timelike curves or nonlinear quantum mechanics improve quantum state discrimination or help solve hard problems?
• Localized closed timelike curves can perfectly distinguish quantum states
• Discriminating quantum states: the multiple Chernoff distance
• Optimal Discrimination of Qubit States - Methods, Solutions, and Properties
• Experimental Simulation of Closed Timelike Curves
• Effective Quantum Time Travel
• Complete analysis for three-qubit mixed-state discrimination
• Multiple-copy state discrimination: Thinking globally, acting locally
• Quantum state cloning using Deutschian closed timelike curves
• Treating Time Travel Quantum Mechanically
• Quantum State Discrimination Using the Minimum Average Number of Copies
• Optimal discrimination of single-qubit mixed states
• Closed Timelike Curves Make Quantum and Classical Computing Equivalent
• Verifiable nonlinear quantum evolution implies failure of density matrices to represent proper mixtures
• Simulations of closed timelike curves
• Multiple-copy state discrimination of noisy qubits
• Closed timelike curves and the second law of thermodynamics

Cited by in corpus (2)

• Nonclassical advantage in metrology established via quantum simulations of hypothetical closed timelike curves
• On the role of closed timelike curves and confinement structure around Kerr-Newman singularity