Quantum branching programs and space-bounded nonuniform quantum complexity
نویسندگان
چکیده
منابع مشابه
Quantum branching programs and space-bounded nonuniform quantum complexity
In this paper, the space complexity of nonuniform quantum computations is investigated. The model chosen for this are quantum branching programs (QBPs), which provide a graphic description of sequential quantum algorithms. In the first part of the paper, simulations between QBPs and nonuniform quantum Turing machines are presented, which allow to transfer lower and upper bound results between t...
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This paper investigates the computational power of space-bounded quantum Turing machines. The following facts are proved for space-constructible space bounds s satisfying s(n) = Ω(log n). 1. Any quantum Turing machine (QTM) running in space s can be simulated by an unbounded error probabilistic Turing machine (PTM) running in space O(s). No assumptions on the probability of error or running tim...
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We present classical simulation techniques for measure once quantum branching programs. For bounded error syntactic quantum branching program of width w that computes a function with error δ we present a classical deterministic branching program of the same length and width at most (1 + 2/(1− 2δ)) that computes the same function. Second technique is a classical stochastic simulation technique f...
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In this paper we show that one qubit polynomial time computations are at least as powerful as NC circuits. More precisely, we define syntactic models for quantum and stochastic branching programs of bounded width and prove upper and lower bounds on their power. We show any NC language can be accepted exactly by a width-2 quantum branching program of polynomial length, in contrast to the classic...
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We present classical simulation techniques for measure once quantum branching programs. For bounded error syntactic quantum branching program of width w that computes a function with error δ we present a classical deterministic branching program of the same length and width at most (1 + 2/(1− 2δ)) that computes the same function. Second technique is a classical stochastic simulation technique f...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2005
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2004.12.031