An iterative quantum-annealing eigensolver with an adaptive trust region; [적응형신뢰영역을이용한반복적양자어닐링고유값해법]

초록

We propose the Adaptive Trust-Region Quantum Annealing Eigensolver (ATR-QAE) for computing the ground states of Hermitian matrices using quantum-annealing measurements. A local quadratic surrogate model is cast as a binary quadratic optimization, from which sign vectors are obtained via the annealer. These are combined with a trust-region update rule to iteratively refine the continuous solution. For the t1 −t2 tight-binding model over the range t2/t1 = 0.1–1.0, the maximum absolute error was 1.41 × 10−3/t1, with errors below 10−4/t1 for many parameter values. For the H4 molecular chain across bond lengths R = 0.4–2.5 Å, chemical accuracy (1.6 × 10−3 Hartree) was reached at all points, with a maximum absolute error of 3.25 × 10−4 Hartree. Furthermore, tests on the LiH molecule over R = 1.0–3.5 Å demonstrated chemical accuracy at all bond lengths, with the exception of R = 3.5 Å, where the error was 4.30 × 10−3 Hartree. These results indicate that ATR-QAE can accurately approximate ground-state energies for diverse physical systems, even with limited quantum resources. © (2025), (Korean Physical Society). All rights reserved.

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