We propose an extension of the variational quantum eigensolver (VQE) that leads to more accurate energy estimations and can be used to study excited states. The method is based on the introduction of a sequence of increasing penalties in the cost function. This approach does not require circuit modifications and thus can be applied with no additional depth cost. Through numerical simulations, we show that we are able to produce variational states with desired physical properties, such as total spin and charge. We assess its performance both on classical simulators and on currently available quantum devices, calculating the potential energy curves of small molecular systems in different physical configurations. Finally, we compare our method to the original VQE and to another extension, obtaining a better agreement with exact simulations for both energy and targeted physical quantities.

Carobene, R., Barison, S., Giachero, A. (2023). Sequence of penalties method to study excited states using VQE. QUANTUM SCIENCE AND TECHNOLOGY, 8(3) [10.1088/2058-9565/acd1a9].

Sequence of penalties method to study excited states using VQE

Giachero, A
2023

Abstract

We propose an extension of the variational quantum eigensolver (VQE) that leads to more accurate energy estimations and can be used to study excited states. The method is based on the introduction of a sequence of increasing penalties in the cost function. This approach does not require circuit modifications and thus can be applied with no additional depth cost. Through numerical simulations, we show that we are able to produce variational states with desired physical properties, such as total spin and charge. We assess its performance both on classical simulators and on currently available quantum devices, calculating the potential energy curves of small molecular systems in different physical configurations. Finally, we compare our method to the original VQE and to another extension, obtaining a better agreement with exact simulations for both energy and targeted physical quantities.
Articolo in rivista - Articolo scientifico
excited states; quantum computing; quantum simulation; VQE;
English
2023
8
3
035014
none
Carobene, R., Barison, S., Giachero, A. (2023). Sequence of penalties method to study excited states using VQE. QUANTUM SCIENCE AND TECHNOLOGY, 8(3) [10.1088/2058-9565/acd1a9].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/415356
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