{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T01:42:11Z","timestamp":1773193331630,"version":"3.50.1"},"reference-count":19,"publisher":"Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften","license":[{"start":{"date-parts":[[2021,4,20]],"date-time":"2021-04-20T00:00:00Z","timestamp":1618876800000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["quantum-journal.org"],"crossmark-restriction":false},"short-container-title":["Quantum"],"abstract":"<jats:p>The <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>p<\/mml:mi><\/mml:math>-stage Quantum Approximate Optimization Algorithm (QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mi>p<\/mml:mi><\/mml:msub><\/mml:math>) is a promising approach for combinatorial optimization on noisy intermediate-scale quantum (NISQ) devices, but its theoretical behavior is not well understood beyond <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>p<\/mml:mi><mml:mo>=<\/mml:mo><mml:mn>1<\/mml:mn><\/mml:math>. We analyze QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mn>2<\/mml:mn><\/mml:msub><\/mml:math> for the <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mtext class=\"MJX-tex-mathit\" mathvariant=\"italic\">maximum cut problem<\/mml:mtext><\/mml:mrow><\/mml:math> (MAX-CUT), deriving a graph-size-independent expression for the expected cut fraction on any <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>D<\/mml:mi><\/mml:math>-regular graph of girth <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mo>&gt;<\/mml:mo><mml:mn>5<\/mml:mn><\/mml:math> (i.e. without triangles, squares, or pentagons).We show that for all degrees <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>D<\/mml:mi><mml:mo>\u2265<\/mml:mo><mml:mn>2<\/mml:mn><\/mml:math> and every <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>D<\/mml:mi><\/mml:math>-regular graph <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>G<\/mml:mi><\/mml:math> of girth <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mo>&gt;<\/mml:mo><mml:mn>5<\/mml:mn><\/mml:math>, QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mn>2<\/mml:mn><\/mml:msub><\/mml:math> has a larger expected cut fraction than QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mn>1<\/mml:mn><\/mml:msub><\/mml:math> on <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>G<\/mml:mi><\/mml:math>. However, we also show that there exists a <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mn>2<\/mml:mn><\/mml:math>-local randomized <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mtext class=\"MJX-tex-mathit\" mathvariant=\"italic\">classical<\/mml:mtext><\/mml:mrow><\/mml:math> algorithm <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>A<\/mml:mi><\/mml:math> such that <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>A<\/mml:mi><\/mml:math> has a larger expected cut fraction than QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mn>2<\/mml:mn><\/mml:msub><\/mml:math> on all <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>G<\/mml:mi><\/mml:math>. This supports our conjecture that for every constant <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>p<\/mml:mi><\/mml:math>, there exists a local classical MAX-CUT algorithm that performs as well as QAOA<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi\/><mml:mi>p<\/mml:mi><\/mml:msub><\/mml:math> on all graphs.<\/jats:p>","DOI":"10.22331\/q-2021-04-20-437","type":"journal-article","created":{"date-parts":[[2021,4,20]],"date-time":"2021-04-20T14:53:06Z","timestamp":1618930386000},"page":"437","update-policy":"https:\/\/doi.org\/10.22331\/q-crossmark-policy-page","source":"Crossref","is-referenced-by-count":44,"title":["Local classical MAX-CUT algorithm outperforms <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>p<\/mml:mi><mml:mo>=<\/mml:mo><mml:mn>2<\/mml:mn><\/mml:math> QAOA on high-girth regular graphs"],"prefix":"10.22331","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9084-6971","authenticated-orcid":false,"given":"Kunal","family":"Marwaha","sequence":"first","affiliation":[{"name":"Berkeley Center for Quantum Information and Computation, University of California, Berkeley, California 94720, USA"}]}],"member":"9598","published-online":{"date-parts":[[2021,4,20]]},"reference":[{"key":"0","doi-asserted-by":"publisher","unstructured":"F. 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