Compact quantum circuits for variational calculations of ro-vibrational
energy levels of molecules on a quantum computer
- URL: http://arxiv.org/abs/2303.09822v1
- Date: Fri, 17 Mar 2023 08:02:38 GMT
- Title: Compact quantum circuits for variational calculations of ro-vibrational
energy levels of molecules on a quantum computer
- Authors: K. Asnaashari, R. V. Krems
- Abstract summary: We show a general approach to computing the ro-vibrational energy levels of molecules by combining the discrete variable representation of molecular Hamiltonians with variational quantum eigensolvers and a greedy search of gate permutations.
To illustrate the generality and adaptability of this approach, we compute the vibrational energy levels of Cr-NH in seven electronic states as well as the vibrational energy levels of van der Waals ArHCl and Mg-HCl.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: While quantum computing algorithms have been successfully applied to
electronic structure of molecules, applications of quantum computing to
molecular dynamics remain scarce. The variability of intra-molecular
interaction potentials gives rise to vibrational states with a wide range of
properties. It is therefore challenging to obtain a general representation of
molecular ro-vibrational states by states of a quantum computer with a limited
number of qubits and quantum gates. We demonstrate a general approach to
computing the ro-vibrational energy levels of molecules by combining the
discrete variable representation of molecular Hamiltonians with variational
quantum eigensolvers and a greedy search of gate permutations, yielding
accurate representations of both ground and excited vibrational states by
compact quantum circuits with a small number of gates. To illustrate the
generality and adaptability of this approach, we compute the vibrational energy
levels of Cr$_2$ in seven electronic states as well as the vibrational energy
levels of van der Waals complexes Ar-HCl and Mg-NH, illustrating that accuracy
of 1 cm$^{-1}$ can be achieved with between 2 and 9 entangling gates.
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