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PolynomialTime Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer
 SIAM J. on Computing
, 1997
"... A digital computer is generally believed to be an efficient universal computing device; that is, it is believed able to simulate any physical computing device with an increase in computation time by at most a polynomial factor. This may not be true when quantum mechanics is taken into consideration. ..."
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Cited by 1278 (4 self)
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A digital computer is generally believed to be an efficient universal computing device; that is, it is believed able to simulate any physical computing device with an increase in computation time by at most a polynomial factor. This may not be true when quantum mechanics is taken into consideration. This paper considers factoring integers and finding discrete logarithms, two problems which are generally thought to be hard on a classical computer and which have been used as the basis of several proposed cryptosystems. Efficient randomized algorithms are given for these two problems on a hypothetical quantum computer. These algorithms take a number of steps polynomial in the input size, e.g., the number of digits of the integer to be factored.
Detrimental Decoherence
, 2007
"... We propose and discuss two conjectures on the nature of information leaks (decoherence) for quantum computers. These conjectures, if (or when) they hold, are damaging for quantum errorcorrection as required by faulttolerant quantum computation. The first conjecture asserts that information leaks f ..."
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Cited by 3 (1 self)
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We propose and discuss two conjectures on the nature of information leaks (decoherence) for quantum computers. These conjectures, if (or when) they hold, are damaging for quantum errorcorrection as required by faulttolerant quantum computation. The first conjecture asserts that information leaks for a pair of substantially entangled qubits are themselves substantially positively correlated. The second conjecture asserts that in a noisy quantum computer with highly entangled qubits there will be a strong effect of error synchronization. We present a more general conjecture for arbitrary noisy quantum systems: prescribing (or describing) noisy quantum systems at a state ρ is subject to error E which “tends to commute” with every unitary operator that stabilizes ρ.
Quantum Computers: Noise Propagation and Adversarial Noise Models
, 2009
"... In this paper we consider adversarial noise models that will fail quantum error correction and faulttolerant quantum computation. We describe known results regarding highrate noise, sequential computation, and reversible noisy computation. We continue by discussing highly correlated noise and the ..."
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Cited by 2 (1 self)
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In this paper we consider adversarial noise models that will fail quantum error correction and faulttolerant quantum computation. We describe known results regarding highrate noise, sequential computation, and reversible noisy computation. We continue by discussing highly correlated noise and the “boundary, ” in terms of correlation of errors, of the “threshold theorem. ” Next, we draw a picture of adversarial forms of noise called (collectively) “detrimental noise.” Detrimental noise is modeled after familiar properties of noise propagation. However, it can have various causes. We start by pointing out the difference between detrimental noise and standard noise models for two qubits and proceed to a discussion of highly entangled states, the rate of noise, and general noisy quantum systems. Research supported in part by an NSF grant, an ISF grant, and a BSF grant.
How quantum computers fail: quantum codes, correlations in physical systems, and noise accumulation
, 2011
"... Dedicated to the memory of Itamar Pitowsky The feasibility of computationally superior quantum computers is one of the most exciting and clearcut scientific questions of our time. The question touches on fundamental issues regarding probability, physics, and computability, as well as on exciting pr ..."
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Dedicated to the memory of Itamar Pitowsky The feasibility of computationally superior quantum computers is one of the most exciting and clearcut scientific questions of our time. The question touches on fundamental issues regarding probability, physics, and computability, as well as on exciting problems in experimental physics, engineering, computer science, and mathematics. We propose three related directions towards a negative answer. The first is a conjecture about physical realizations of quantum codes, the second has to do with correlations in stochastic physical systems, and the third proposes a model for quantum evolutions when noise accumulates. 1