Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 18: Poster II

QI 18.22: Poster

Wednesday, March 20, 2024, 11:00–14:30, Poster A

Variational Quantum Quasi-Particle Operators — •Gary Schmiedinghoff¹ and Benedikt Fauseweh² — ¹German Aerospace Center, Cologne — ²TU Dortmund, Dortmund

Quantum simulations are the most promising area for finding quantum advantage on near-term devices. Variational methods are powerful tools to approximate the ground state of a quantum system, but finding excited states, such as done in quantum deflation algorithms, is costly due to the repetitive optimization and accumulation of errors. We propose an ansatz for excitation operators on periodic systems that are optimized once to create a single excitation of tunable momentum. This operator can then be used to prepare various excited states by being applied to the, for instance variationally obtained, ground state. The ansatz is constructed perturbatively, such that the accuracy can be improved depending on the computational capacities, while fulfilling fundamental commutation conditions.

Keywords: Variational Quantum Algorithm; Condensed Matter Systems; Periodic Systems; Excited States; Method Development