Signatures of quantum noise in the operation of Deutsch's algorithm

Fuente: arXiv
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Main Authors: Strzałka, Małgorzata, Roszak, Katarzyna
Format: Preprint
Published: 2026
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author Strzałka, Małgorzata
Roszak, Katarzyna
author_facet Strzałka, Małgorzata
Roszak, Katarzyna
contents We use Deutsch's algorithm as a stand in for more complex quantum algorithms in order to determine how quantum properties of an environment manifest themselves in results that can be obtained on quantum computers. We model pure dephasing in two different ways; one keeps the full density matrix of the qubits and environments (quantum) while the other uses Kraus operators (classical). We find that a single run of the algorithm yields the same effect in both cases, but running the algorithm twice leads to stark differences. Taking correlations and interplay between different decoherence processes into account leads to a slowing of decoherence effects for balanced functions. For constant functions, the effect is much more pronounced, and there is a qualitative change in the dependence of measurement outcomes on decoherence. We present results obtained on one of the IBM Quantum processors, which fully reproduce the predicted effect regardless of the assumptions made in the derivation. We further illustrate the findings on NV center spin qubits, which show more complex behavior due to a small size of the environment.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19047
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Signatures of quantum noise in the operation of Deutsch's algorithm
Strzałka, Małgorzata
Roszak, Katarzyna
Quantum Physics
We use Deutsch's algorithm as a stand in for more complex quantum algorithms in order to determine how quantum properties of an environment manifest themselves in results that can be obtained on quantum computers. We model pure dephasing in two different ways; one keeps the full density matrix of the qubits and environments (quantum) while the other uses Kraus operators (classical). We find that a single run of the algorithm yields the same effect in both cases, but running the algorithm twice leads to stark differences. Taking correlations and interplay between different decoherence processes into account leads to a slowing of decoherence effects for balanced functions. For constant functions, the effect is much more pronounced, and there is a qualitative change in the dependence of measurement outcomes on decoherence. We present results obtained on one of the IBM Quantum processors, which fully reproduce the predicted effect regardless of the assumptions made in the derivation. We further illustrate the findings on NV center spin qubits, which show more complex behavior due to a small size of the environment.
title Signatures of quantum noise in the operation of Deutsch's algorithm
topic Quantum Physics
url https://arxiv.org/abs/2605.19047