منابع مشابه
Lower bounds on the size of semi-quantum finite automata
In the literature, there exist several interesting hybrid models of finite automata which have both quantum and classical states. We call them semi-quantum automata. In this paper, we compare the descriptional power of these models with that of DFA. Specifically, we present a uniform method that gives a lower bound on the size of the three existing main models of semi-quantum automata, and this...
متن کاملLower Bounds for Generalized Quantum Finite Automata
We obtain several lower bounds on the language recognition power of Nayak’s [12] generalized quantum finite automata (GQFA). Techniques for proving lower bounds on Kondacs and Watrous’ one-way quantum finite automata (KWQFA) were introduced by Ambainis and Freivalds [2], and were expanded in a series of papers. We show that many of these techniques can be adapted to prove lower bounds for GQFAs...
متن کاملOptimal Lower Bounds for Quantum Automata and Random Access Codes
Consider the finite regular language Ln = {w0 | w ∈ {0, 1}, |w| ≤ n}. In [3] it was shown that while this language is accepted by a deterministic finite automaton of size O(n), any one-way quantum finite automaton (QFA) for it has size 2 . This was based on the fact that the evolution of a QFA is required to be reversible. When arbitrary intermediate measurements are allowed, this intuition bre...
متن کاملFormula Size Lower Bounds and Quantum States
Everyone agrees that building a quantum computer is hard. But some people think it must be impossible for a fundamental physical reason. Two computer scientists who think this are Leonid Levin and Oded Goldreich. Levin, for example, says that the exponentially small amplitudes that arise in Shor’s factoring algorithm are absurd—that they take us far beyond quantum mechanics’ regime of demonstra...
متن کاملAlgorithms and lower bounds in finite automata size complexity
In this thesis we investigate the relative succinctness of several types of finite automata, focusing mainly on the following four basic models: one-way deterministic (1dfas), one-way nondeterministic (1nfas), two-way deterministic (2dfas), and two-way nondeterministic (2nfas). We first establish the exact values of the trade-offs for all conversions from two-way to one-way automata. Specifical...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2014
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2014.07.004