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ЖУРНАЛЫ // Письма в Журнал экспериментальной и теоретической физики // Архив

Письма в ЖЭТФ, 2002, том 76, выпуск 11, страницы 799–804 (Mi jetpl2996)

Эта публикация цитируется в 1 статье

РАЗНОЕ

How behavior of systems with sparse spectrum can be predicted on a quantum computer

Yu. I. Ozhigov

Insitute of Physics and Technology, Russian Academy of Sciences, Moscow

Аннотация: Call a spectrum of Hamiltonian $H$ sparse if each eigenvalue can be quickly restored within $\varepsilon$ from its rough approximation within $\varepsilon_1$ by means of some classical algorithm. It is shown how a behavior of system with sparse spectrum up to time $T={(1-\rho)}/{14\varepsilon}$ can be predicted on a quantum computer with the time complexity $t={4}/{(1-\rho)\varepsilon_1}$ plus the time of classical algorithm, where $\rho$ is the fidelity. The quantum knowledge of Hamiltonian eigenvalues is considered as the new Hamiltonian $W_H$ whose action on each eigenvector of $H$ gives the corresponding eigenvalue. Speedup of an evolution for systems with the sparse spectrum is possible because for such systems the Hamiltonian $W_H$ can be quickly simulated on the quantum computer. For an arbitrary system (even in the classical case) its behavior cannot be predicted on a quantum computer even for one step ahead. By this method we can also restore the history with the same efficiency.

PACS: 03.67.Lx

Поступила в редакцию: 01.04.2002
Исправленный вариант: 30.10.2002

Язык публикации: английский


 Англоязычная версия: Journal of Experimental and Theoretical Physics Letters, 2002, 76:11, 675–680

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