Quantum diagonalization of Hermitean matrices

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Abstract

To measure an observable of a quantum mechanical system leaves it in one of its eigenstates and the result of the measurement is one of its eigenvalues. This process is shown to be a computational resource: Hermitean (N ×N) matrices can be diagonalized, in principle, by performing appropriate quantum mechanical measurements. To do so, one considers the given matrix as an observable of a single spin with appropriate length s which can be measured using a generalized Stern-Gerlach apparatus. Then, each run provides one eigenvalue of the observable. As the underlying working principle is the `collapse of the wavefunction' associated with a measurement, the procedure is neither a digital nor an analogue calculation - it defines thus a new example of a quantum mechanical method of computation.
Original languageEnglish
Pages (from-to)5619-5624
Number of pages5
JournalJournal of Physics A: Mathematical and General
Volume34
Issue number27
DOIs
Publication statusPublished - 13 Jul 2001

Bibliographical note

© 2001 IOP Publishing Ltd. This is an author produced version of a paper published in Journal of Physics A: Mathematical and General.

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