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Related papers: A small 1-way quantum finite automaton

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This paper establishes a lower bound on the number of states necessary in the worst case to simulate an $n$-state two-way nondeterministic finite automaton (2NFA) by a one-way unambiguous finite automaton (UFA). It is proved that for every…

Formal Languages and Automata Theory · Computer Science 2024-12-10 Semyon Petrov , Alexander Okhotin

Time-space tradeoff has been studied in a variety of models, such as Turing machines, branching programs, and finite automata, etc. While communication complexity as a technique has been applied to study finite automata, it seems it has not…

Computational Complexity · Computer Science 2023-12-01 Shenggen Zheng , Yaqiao Li , Minghua Pan , Jozef Gruska , Lvzhou Li

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

This research describes a three dimensional quantum cellular automaton (QCA) which can simulate all other 3D QCA. This intrinsically universal QCA belongs to the simplest subclass of QCA: Partitioned QCA (PQCA). PQCA are QCA of a particular…

Quantum Physics · Physics 2017-08-29 Pablo Arrighi , Jonathan Grattage

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

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

We construct a probabilistic finite automaton (PFA) with 7 states and an input alphabet of 5 symbols for which the PFA Emptiness Problem is undecidable. The only input for the decision problem is the starting distribution. For the proof, we…

Formal Languages and Automata Theory · Computer Science 2024-12-09 Günter Rote

Generalized finite automata (GFAs), probabilistic finite automata (PFAs), and one-way general quantum finite automata (1gQFA) recognize the same strict-cutpoint languages, but the state complexity of exact probabilistic simulation has…

Formal Languages and Automata Theory · Computer Science 2026-04-09 Zeyu Chen , Junde Wu

A two-way deterministic finite state automaton with one counter (2D1CA) is a fundamental computational model that has been examined in many different aspects since sixties, but we know little about its power in the case of unary languages.…

Formal Languages and Automata Theory · Computer Science 2014-07-09 Marzio De Biasi , Abuzer Yakaryilmaz

Finite automata (FA) are a fundamental computational abstraction that is widely used in practice for various tasks in computer science, linguistics, biology, electrical engineering, and artificial intelligence. Given an input word, an FA…

Artificial Intelligence · Computer Science 2026-04-22 Jaime Cuartas Granada , Alexey Ignatiev , Peter J. Stuckey

We present a simple construction of quantum automata which achieve an exponential advantage over classical finite automata. Our automata use \frac{4}{\epsilon} \log 2p + O(1) states to recognize a language that requires p states…

Quantum Physics · Physics 2008-05-13 Andris Ambainis , Nikolajs Nahimovs

The 2-way quantum finite automaton introduced by Kondacs and Watrous can accept non-regular languages with bounded error in polynomial time. If we restrict the head of the automaton to moving classically and to moving only in one direction,…

Quantum Physics · Physics 2007-05-23 Alex Brodsky , Nicholas Pippenger

Quantum cellular automata (QCA) constitute space and time homogeneous discrete models for quantum field theories (QFTs). Although QFTs are defined without reference to particles, computations are done in terms of Feynman diagrams, which are…

Quantum Physics · Physics 2016-01-27 David A. Meyer , Asif Shakeel

Consider the finite regular language L_n = {w0 : w \in {0,1}^*, |w| \le n}. It was shown by Ambainis, Nayak, Ta-Shma and Vazirani that while this language is accepted by a deterministic finite automaton of size O(n), any one-way quantum…

Quantum Physics · Physics 2007-05-23 Ashwin Nayak

We construct zero-error quantum finite automata (QFAs) for promise problems which cannot be solved by bounded-error probabilistic finite automata (PFAs). Here is a summary of our results: - There is a promise problem solvable by an exact…

Quantum Physics · Physics 2014-04-11 Jibran Rashid , Abuzer Yakaryilmaz

The work presents some new algorithms realized recently in the package TESTAS. They decide whether or not deterministic finite automaton (DFA) is synchronizing, several procedures find relatively short synchronizing words and a…

Formal Languages and Automata Theory · Computer Science 2020-11-12 Avraham N. Trahtman

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…

Quantum computation based on quantum cellular automata (QCA) can greatly reduce the control and precision necessary for experimental implementations of quantum information processing. A QCA system consists of a few species of qubits in…

Quantum Physics · Physics 2009-11-10 Yaakov S. Weinstein , C. Stephen Hellberg

We examine the characteristic features of reversible and quantum computations in the presence of supplementary external information, known as advice. In particular, we present a simple, algebraic characterization of languages recognized by…

Quantum Physics · Physics 2015-08-25 Tomoyuki Yamakami

We prove that, paying a polynomial increase in size only, every unrestricted two-way nondeterministic finite automaton (2NFA) can be complemented by a 1-limited automaton (1-LA), a nondeterministic extension of 2NFAs still characterizing…

Formal Languages and Automata Theory · Computer Science 2025-07-16 Bruno Guillon , Luca Prigioniero , Javad Taheri