%0 Journal Article
%A Jattana, Manpreet Singh
%A Jin, Fengping
%A De Raedt, Hans
%A Michielsen, Kristel
%T Improved Variational Quantum Eigensolver Via Quasidynamical Evolution
%J Physical review applied
%V 19
%N 2
%@ 2331-7019
%C College Park, Md. [u.a.]
%I American Physical Society
%M FZJ-2023-01121
%P 024047
%D 2023
%X The variational quantum eigensolver (VQE) is a hybrid quantum classical algorithm designed for current and near-term quantum devices. Despite its initial success, there is a lack of understanding involving several of its key aspects. There are problems with VQE that forbid a favorable scaling towards quantum advantage. In order to alleviate the problems, we propose and extensively test a quantum annealing inspired heuristic that supplements VQE. The improved VQE enables an efficient initial state-preparation mechanism, in a recursive manner, for a quasidynamical unitary evolution. We conduct an in-depth scaling analysis of finding the ground-state energies with increasing lattice sizes of the Heisenberg model, employing simulations of up to 40 qubits that manipulate the complete state vector. In addition to systematically finding the ground-state energy, we observe that it avoids barren plateaus, escapes local minima, and works with low-depth circuits. For the current devices, we further propose a benchmarking toolkit using a mean-field model and test it on IBM Q devices. Realistic gate execution times estimate a longer computational time to complete the same computation on a fully functional error-free quantum computer than on a quantum computer emulator implemented on a classical computer. However, our proposal can be expected to help accurate estimations of the ground-state energies beyond 50 qubits when the complete state vector can no longer be stored on a classical computer, thus enabling quantum advantage.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000936544700002
%R 10.1103/PhysRevApplied.19.024047
%U https://juser.fz-juelich.de/record/996121