Quantum algorithm for obtaining the energy spectrum of molecular systems

Hefeng Wang, Sabre Kais, Alán Aspuru-Guzik, Mark R. Hoffmann

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Simulating a quantum system is more efficient on a quantum computer than on a classical computer. The time required for solving the Schrödinger equation to obtain molecular energies has been demonstrated to scale polynomially with system size on a quantum computer, in contrast to the well-known result of exponential scaling on a classical computer. In this paper, we present a quantum algorithm to obtain the energy spectrum of molecular systems based on the multiconfigurational self-consistent field (MCSCF) wave function. By using a MCSCF wave function as the initial guess, the excited states are accessible. Entire potential energy surfaces of molecules can be studied more efficiently than if the simpler Hartree-Fock guess was employed. We show that a small increase of the MCSCF space can dramatically increase the success probability of the quantum algorithm, even in regions of the potential energy surface that are far from the equilibrium geometry. For the treatment of larger systems, a multi-reference configuration interaction approach is suggested. We demonstrate that such an algorithm can be used to obtain the energy spectrum of the water molecule.

Original languageEnglish
Pages (from-to)5388-5393
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume10
Issue number35
DOIs
Publication statusPublished - 8 Sep 2008
Externally publishedYes

Fingerprint

self consistent fields
Quantum computers
Potential energy surfaces
energy spectra
quantum computers
Wave functions
potential energy
wave functions
Molecules
Excited states
configuration interaction
molecules
scaling
Geometry
Water
geometry
water
excitation
energy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Atomic and Molecular Physics, and Optics

Cite this

Quantum algorithm for obtaining the energy spectrum of molecular systems. / Wang, Hefeng; Kais, Sabre; Aspuru-Guzik, Alán; Hoffmann, Mark R.

In: Physical Chemistry Chemical Physics, Vol. 10, No. 35, 08.09.2008, p. 5388-5393.

Research output: Contribution to journalArticle

Wang, Hefeng ; Kais, Sabre ; Aspuru-Guzik, Alán ; Hoffmann, Mark R. / Quantum algorithm for obtaining the energy spectrum of molecular systems. In: Physical Chemistry Chemical Physics. 2008 ; Vol. 10, No. 35. pp. 5388-5393.
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