2001/10/02 by Tomohiro Yamasaki, Yamasaki, Tomohiro, Hirotada Kobayashi +3
Computer Science · Physics and Astronomy · #Machine Learning and Algorithms #Quantum Computing Algorithms and Architecture #Quantum-Dot Cellular Automata #cs.CC #quant-ph
paper · pdf · doi:10.48550/arxiv.cs/0110005
LaTeX2e, 14 pages, 3 figures
arxiv created 2001/10/02 · arxiv updated 2009/11/30
After the first treatments of quantum finite state automata by Moore and Crutchfield and by Kondacs and Watrous, a number of papers study the power of quantum finite state automata and their variants. This paper introduces a model of two-way quantum one-counter automata (2Q1CAs), combining the model of two-way quantum finite state automata (2QFAs) by Kondacs and Watrous and the model of one-way quantum one-counter automata (1Q1CAs) by Kravtsev. We give the definition of 2Q1CAs with well-formedness conditions. It is proved that 2Q1CAs are at least as powerful as classical two-way deterministic one-counter automata (2D1CAs), that is, every language L recognizable by 2D1CAs is recognized by 2Q1CAs with no error. It is also shown that several non-context-free languages including an bn2 and an b2n are recognizable by 2Q1CAs with bounded error.