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Related papers: Implications of quantum automata for contextuality

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This paper deals with the size complexity of minimal {\it two-way quantum finite automata} (2qfa's) necessary for operations to perform on all inputs of each fixed length. Such a complexity measure, known as state complexity of operations,…

Discrete Mathematics · Computer Science 2008-07-04 Daowen Qiu

Quantum finite automata have been studied intensively since their introduction in late 1990s as a natural model of a quantum computer with finite-dimensional quantum memory space. This paper seeks their direct application to interactive…

Quantum Physics · Physics 2016-05-26 Harumichi Nishimura , Tomoyuki Yamakami

Quantum finite automata (QFAs) have been extensively studied in the literature. In this paper, we define and systematically study quantum B\"uchi automata (QBAs) over infinite words to model the long-term behavior of quantum systems, which…

Logic in Computer Science · Computer Science 2024-07-29 Qisheng Wang , Mingsheng Ying

In this paper we explore the power of AM for the case that verifiers are {\em two-way finite automata with quantum and classical states} (2QCFA)--introduced by Ambainis and Watrous in 2002--and the communications are classical. It is of…

Computational Complexity · Computer Science 2015-05-05 Shenggen Zheng , Daowen Qiu , Jozef Gruska

The nondeterministic quantum finite automaton (NQFA) is the only known case where a one-way quantum finite automaton (QFA) model has been shown to be strictly superior in terms of language recognition power to its probabilistic counterpart.…

Computational Complexity · Computer Science 2014-01-29 Abuzer Yakaryilmaz , A. C. Cem Say

Quantum finite automata (QFA) are basic computational devices that make binary decisions using quantum operations. They are known to be exponentially memory efficient compared to their classical counterparts. Here, we demonstrate an…

Quantum Physics · Physics 2022-07-06 Stephen Z. D. Plachta , Markus Hiekkamäki , Abuzer Yakaryılmaz , Robert Fickler

We study 1-way quantum finite automata (QFAs) and compare them with their classical counterparts. We show that 1-way QFAs can be very space efficient. We construct a 1-way QFAs that are quadratically smaller than any equivalent…

Quantum Physics · Physics 2007-05-23 Arnolds Kikusts

This paper identifies exact probabilistic simulation cost as the natural quantitative measure of quantum advantage for finite automata under strict cutpoints. It gives sharp simulation laws for two representative models. A one-way finite…

Quantum Physics · Physics 2026-05-12 Zeyu Chen , Junde Wu

Given a Probabilistic Finite Automata (PFA), a set of states S, and an error threshold e > 0, our algorithm approximates the infimum probability (quantifying over all infinite words) that the automata reaches S. Our result contrasts with…

Logic in Computer Science · Computer Science 2010-09-21 Sergio Giro

We study the recognition of R-trivial idempotent (R1) languages by various models of "decide-and-halt" quantum finite automata (QFA) and probabilistic reversible automata (DH-PRA). We introduce bistochastic QFA (MM-BQFA), a model which…

Formal Languages and Automata Theory · Computer Science 2011-09-07 Marats Golovkins , Maksim Kravtsev , Vasilijs Kravcevs

The study of quantum finite automata (QFAs) is one of the possible approaches in exploring quantum computers with finite memory. Despite being one of the most restricted models, Moore-Crutchfield quantum finite automaton (MCQFA) is proven…

Quantum Physics · Physics 2022-12-13 Özlem Salehi , Abuzer Yakaryılmaz

One of the properties of Kondacs-Watrous model of quantum finite automata (QFA) is that the probability of the correct answer for a QFA cannot be amplified arbitrarily. In this paper, we determine the maximum probabilities achieved by QFAs…

Quantum Physics · Physics 2007-05-23 Andris Ambainis , Arnolds Kikusts

Quantum finite automata can be used for pattern recognition. Present implementations on actual quantum devices face decoherence issues, which compromise the quality of long strings computation. In this work, we focus on the Measure Once…

It is known that for some languages quantum finite automata are more efficient than classical counterparts. Particularly, a QFA recognizing the language $MOD_p$ has an exponential advantage over the classical finite automata. However, the…

Quantum Physics · Physics 2023-01-02 Aliya Khadieva , Mansur Ziatdinov

One-way quantum finite automata together with classical states (1QFAC) proposed in [Journal of Computer and System Sciences 81(2) (2015) 359--375] is a new one-way quantum finite automata (1QFA) model that integrates quantum finite automata…

Quantum Physics · Physics 2021-12-09 Ligang Xiao , Daowen Qiu

In the field of computational logic, two classes of finite automata are considered fundamental: deterministic and nondeterministic automata (DFAs and NFAs). In a more fine-grained approach three natural intermediate classes were introduced,…

Formal Languages and Automata Theory · Computer Science 2025-07-22 Karolina Drabik , Anita Dürr , Fabian Frei , Filip Mazowiecki , Karol Węgrzycki

Quantum computing is concerned with computer technology based on the principles of quantum mechanics, with operations performed at the quantum level. Quantum computational models make it possible to analyze the resources required for…

Formal Languages and Automata Theory · Computer Science 2019-01-24 Amandeep Singh Bhatia , Ajay Kumar

We reinvestigate known lower bounds for the Intersection Non-Emptiness Problem for Deterministic Finite Automata (DFA's). We first strengthen conditional time complexity lower bounds from T. Kasai and S. Iwata (1985) which showed that…

Formal Languages and Automata Theory · Computer Science 2026-03-24 Michael Wehar

We define a new subclass of nondeterministic finite automata for prefix-closed languages called Flanked Finite Automata (FFA). We show that this class enjoys good complexity properties while preserving the succinctness of nondeterministic…

Formal Languages and Automata Theory · Computer Science 2015-09-23 Florent Avellaneda , Silvano Dal Zilio , Jean-Baptiste Raclet

Quantum finite automata, as well as quantum pushdown automata (QPA) were first introduced by C. Moore and J. P. Crutchfield. In this paper we introduce the notion of QPA in a non-equivalent way, including unitarity criteria, by using the…

Quantum Physics · Physics 2011-06-14 Marats Golovkins