Tomography of a displacement photon counter for discrimination of single-rail optical qubits. (4th April 2018)

• Record Type: Journal Article
• Authors: Izumi, Shuro; Neergaard-Nielsen, Jonas S; Andersen, Ulrik L
• Is Part Of: Journal of physics. Volume 51:Number 8(2018:Apr. 15)
• Publication Date: 2018-04-04
• Subjects: Quantum state discrimination -- displacement photon counting -- detector tomography; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/aab5dd
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: We investigate the performance of a detection strategy composed of a displacement operation and a photon counter, which is known as a beneficial tool in optical coherent communications, to the quantum state discrimination of the two superpositions of vacuum and single photon states corresponding to the σ ̂ x eigenstates in the single-rail encoding of photonic qubits. We experimentally characterize the detection strategy in vacuum-single photon two-dimensional space using quantum detector tomography and evaluate the achievable discrimination error probability from the reconstructed measurement operators. We furthermore derive the minimum error rate obtainable with Gaussian transformations and homodyne detection. Our proof-of-principle experiment shows that the proposed scheme can achieve a discrimination error surpassing homodyne detection.