LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism

We present a novel formalism to both understand and construct mixers that preserve a given subspace. The method connects and utilizes the stabilizer formalism that is used in error correcting codes. This can be useful in the setting when the quantum approximate optimization algorithm (QAOA), a popul...

Full description

Saved in:
Bibliographic Details
Main Authors: Franz G. Fuchs, Ruben Pariente Bassa
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2024-11-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2024-11-25-1535/pdf/
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850158851523870720
author Franz G. Fuchs
Ruben Pariente Bassa
author_facet Franz G. Fuchs
Ruben Pariente Bassa
author_sort Franz G. Fuchs
collection DOAJ
description We present a novel formalism to both understand and construct mixers that preserve a given subspace. The method connects and utilizes the stabilizer formalism that is used in error correcting codes. This can be useful in the setting when the quantum approximate optimization algorithm (QAOA), a popular meta-heuristic for solving combinatorial optimization problems, is applied in the setting where the constraints of the problem lead to a feasible subspace that is large but easy to specify. The proposed method gives a systematic way to construct mixers that are resource efficient in the number of controlled not gates and can be understood as a generalization of the well-known X and XY mixers and a relaxation of the Grover mixer: Given a basis of any subspace, a resource efficient mixer can be constructed that preserves the subspace. The numerical examples provided show a dramatic reduction of CX gates when compared to previous results. We call our approach logical X-Mixer or logical X QAOA ($\textbf{LX-QAOA}$), since it can be understood as dividing the subspace into code spaces of stabilizers S and consecutively applying logical rotational X gates associated with these code spaces. Overall, we hope that this new perspective can lead to further insight into the development of quantum algorithms.
format Article
id doaj-art-62cf04db95484b6ebcc8459266340d53
institution OA Journals
issn 2521-327X
language English
publishDate 2024-11-01
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
record_format Article
series Quantum
spelling doaj-art-62cf04db95484b6ebcc8459266340d532025-08-20T02:23:45ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2024-11-018153510.22331/q-2024-11-25-153510.22331/q-2024-11-25-1535LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalismFranz G. FuchsRuben Pariente BassaWe present a novel formalism to both understand and construct mixers that preserve a given subspace. The method connects and utilizes the stabilizer formalism that is used in error correcting codes. This can be useful in the setting when the quantum approximate optimization algorithm (QAOA), a popular meta-heuristic for solving combinatorial optimization problems, is applied in the setting where the constraints of the problem lead to a feasible subspace that is large but easy to specify. The proposed method gives a systematic way to construct mixers that are resource efficient in the number of controlled not gates and can be understood as a generalization of the well-known X and XY mixers and a relaxation of the Grover mixer: Given a basis of any subspace, a resource efficient mixer can be constructed that preserves the subspace. The numerical examples provided show a dramatic reduction of CX gates when compared to previous results. We call our approach logical X-Mixer or logical X QAOA ($\textbf{LX-QAOA}$), since it can be understood as dividing the subspace into code spaces of stabilizers S and consecutively applying logical rotational X gates associated with these code spaces. Overall, we hope that this new perspective can lead to further insight into the development of quantum algorithms.https://quantum-journal.org/papers/q-2024-11-25-1535/pdf/
spellingShingle Franz G. Fuchs
Ruben Pariente Bassa
LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
Quantum
title LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
title_full LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
title_fullStr LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
title_full_unstemmed LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
title_short LX-mixers for QAOA: Optimal mixers restricted to subspaces and the stabilizer formalism
title_sort lx mixers for qaoa optimal mixers restricted to subspaces and the stabilizer formalism
url https://quantum-journal.org/papers/q-2024-11-25-1535/pdf/
work_keys_str_mv AT franzgfuchs lxmixersforqaoaoptimalmixersrestrictedtosubspacesandthestabilizerformalism
AT rubenparientebassa lxmixersforqaoaoptimalmixersrestrictedtosubspacesandthestabilizerformalism