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Issue 35, 2008
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Quantum algorithm for obtaining the energy spectrum of molecular systems

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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.

Graphical abstract: Quantum algorithm for obtaining the energy spectrum of molecular systems

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Publication details

The article was received on 20 Mar 2008, accepted on 10 Jun 2008 and first published on 22 Jul 2008


Article type: Paper
DOI: 10.1039/B804804E
Citation: Phys. Chem. Chem. Phys., 2008,10, 5388-5393
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    Quantum algorithm for obtaining the energy spectrum of molecular systems

    H. Wang, S. Kais, A. Aspuru-Guzik and M. R. Hoffmann, Phys. Chem. Chem. Phys., 2008, 10, 5388
    DOI: 10.1039/B804804E

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