Many-Body Excited States with a Contracted Quantum Eigensolver
- URL: http://arxiv.org/abs/2305.09653v1
- Date: Tue, 16 May 2023 17:53:07 GMT
- Title: Many-Body Excited States with a Contracted Quantum Eigensolver
- Authors: Scott E. Smart, Davis M. Welakuh, Prineha Narang
- Abstract summary: We develop an excited state approach based on the contracted quantum eigensolver (ES-CQE)
We show the ES-CQE near-exact accuracy across the majority of states, covering regions of strong and weak electron correlation.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Calculating ground and excited states is an exciting prospect for near-term
quantum computing applications, and accurate and efficient algorithms are
needed to assess viable directions. We develop an excited state approach based
on the contracted quantum eigensolver (ES-CQE), which iteratively attempts to
find a solution to a contraction of the Schr{\"o}dinger equation projected onto
a subspace, and does not require a priori information on the system. We focus
on the anti-Hermitian portion of the equation, leading to a two-body unitary
ansatz. We investigate the role of symmetries, initial states, constraints, and
overall performance within the context of the model rectangular ${\rm H}_4$
system. We show the ES-CQE achieves near-exact accuracy across the majority of
states, covering regions of strong and weak electron correlation, while also
elucidating challenging instances for two-body unitary ansatz.
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