Adaptive quantum circuit construction for ground state preparation of multiorbital impurity models

eg impurity-bath model and ground state energy convergence graph
(a) Schematic illustration of the 𝑒𝑔eg impurity-bath model.
(b) Ground state energy convergence as a function of the number of variational parameters in the adaptive variational quantum eigensolver simulations in the presence of quantum noise. The simulation uses three different operator pools of size 56, 16 and 10, and 2162^16 shots for circuit measurements.

Scientific Achievement

Different variational quantum eigensolvers for ground state preparation of multiorbital embedding impurity models were benchmarked in the presence of hardware noise.

Significance and Impact

Identifying optimal simulation parameters is an important step towards realizing correlated material simulations via quantum embedding approaches on quantum computers.

Research Details

  • Devising and benchmarking a new operator pool composed of pairwise commutators of Hamiltonian terms. Optimal choice of operators results in compact circuits for ground state preparation.
  • Ground state fidelity 𝑓>99.9% is obtained using a modest 214 shots in the presence of quantum noise.
  • Discovery of a dichotomy that pool size reduction can make the classical optimization more challenging.

A. Mukherjee, N. F. Berthusen, J. C. Getelina, P. P. Orth, and Y.-X. Yao, Comparative Study of Adaptive Variational Quantum Eigensolvers for Multi-Orbital Impurity Models, Communications Physics (2022).