An Enhanced Photonic Quantum Finite Automaton

TL;DR

This paper improves an optical quantum finite automaton's performance by utilizing both photon polarization outputs and analyzing detector dark counts, enhancing recognition accuracy for unary periodic languages.

Contribution

It introduces strategies that leverage both orthogonal photon polarizations and considers detector dark counts to enhance automaton performance.

Findings

Performance improved by using both polarization outputs

Dark counts impact automaton accuracy

Enhanced confidence amplification techniques

Abstract

In a recent paper we have described an optical implementation of a measure-once one-way quantum finite automaton recognizing a well-known family of unary periodic languages, accepting words not in the language with a given error probability. To process input words, the automaton exploits the degree of polarization of single photons and, to reduce the acceptance error probability, a technique of confidence amplification using the photon counts is implemented. In this paper, we show that the performance of this automaton may be further improved by using strategies that suitably consider both the orthogonal output polarizations of the photon. In our analysis, we also take into account how detector dark counts may affect the performance of the automaton.