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Updated: Dec 31, 2025
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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
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Exact parameterization of fermionic wave functions via unitary coupled cluster theory
Francesco A Evangelista1, Garnet Kin-Lic Chan2, Gustavo E Scuseria3
1Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA.
The Journal of Chemical Physics
|January 3, 2020
Summary
This study analyzes unitary coupled cluster (UCC) theory, finding that disentangled UCC wave functions can exactly parameterize any quantum state. This enables Trotter-error-free quantum computing applications using UCC.
Area of Science:
- Quantum chemistry
- Computational physics
- Quantum computing
Background:
- Unitary Coupled Cluster (UCC) theory is a powerful quantum chemistry method.
- Conventional UCC parameterization has limitations in representing all quantum states exactly.
Purpose of the Study:
- To formally analyze the exactness of different unitary coupled cluster (UCC) theories.
- To develop Trotter-error-free UCC parameterizations for quantum computing.
Main Methods:
- Formal analysis of particle-hole excitation and de-excitation operators.
- Differential cluster analysis to determine UCC amplitudes.
- Numerical exploration of conventional UCC exactness.
- Proof of exact parameterization for disentangled UCC wave functions.
Main Results:
- Conventional UCC exactness is linked to critical points of the UCC exponential mapping.
- A family of disentangled UCC wave functions is proven to exactly parameterize any quantum state.
- An exact disentangled UCC parameterization using substitution operators is constructed.
Conclusions:
- Disentangled UCC provides a pathway to exact quantum state representation.
- This work enables the development of Trotter-error-free UCC algorithms for quantum computation.
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