Quantum algorithm for obtaining the energy spectrum of a physical system

Hefeng Wang, Sahel Ashhab, Franco Nori

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We present a polynomial-time quantum algorithm for obtaining the energy spectrum of a physical system, i.e., the differences between the eigenvalues of the system's Hamiltonian, provided that the spectrum of interest contains at most a polynomially increasing number of energy levels. A probe qubit is coupled to a quantum register that represents the system of interest such that the probe exhibits a dynamical response only when it is resonant with a transition in the system. By varying the probe's frequency and the system-probe coupling operator, any desired part of the energy spectrum can be obtained. The algorithm can also be used to deterministically prepare any energy eigenstate. As an example, we have simulated running the algorithm and obtained the energy spectrum of the water molecule.

Original languageEnglish
Article number062304
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume85
Issue number6
DOIs
Publication statusPublished - 5 Jun 2012
Externally publishedYes

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energy spectra
probes
registers
eigenvectors
polynomials
eigenvalues
energy levels
operators
water
molecules
energy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Quantum algorithm for obtaining the energy spectrum of a physical system. / Wang, Hefeng; Ashhab, Sahel; Nori, Franco.

In: Physical Review A - Atomic, Molecular, and Optical Physics, Vol. 85, No. 6, 062304, 05.06.2012.

Research output: Contribution to journalArticle

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