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Central to classical game theory is the efficient algorithmic computation of Nash equilibria, which represent optimal strategies for both players. In 2008, Jain and Watrous proposed the first classical algorithm for computing equilibria in quantum zero-sum games using the Matrix Multiplicative Weight Updates (MMWU) method to achieve a convergence rate of <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mi class=\"MJX-tex-caligraphic\" mathvariant=\"script\">O<\/mml:mi><\/mml:mrow><mml:mo stretchy=\"false\">(<\/mml:mo><mml:mi>d<\/mml:mi><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mo>\/<\/mml:mo><\/mml:mrow><mml:msup><mml:mi>&amp;#x03F5;<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><mml:mo stretchy=\"false\">)<\/mml:mo><\/mml:math> iterations to <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>&amp;#x03F5;<\/mml:mi><\/mml:math>-Nash equilibria in the <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msup><mml:mn>4<\/mml:mn><mml:mi>d<\/mml:mi><\/mml:msup><\/mml:math>-dimensional spectraplex. In this work, we propose a hierarchy of quantum optimization algorithms that generalize MMWU via an extra-gradient mechanism. Notably, within this proposed hierarchy, we introduce the Optimistic Matrix Multiplicative Weights Update (OMMWU) algorithm and establish its average-iterate convergence complexity as <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mi class=\"MJX-tex-caligraphic\" mathvariant=\"script\">O<\/mml:mi><\/mml:mrow><mml:mo stretchy=\"false\">(<\/mml:mo><mml:mi>d<\/mml:mi><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mo>\/<\/mml:mo><\/mml:mrow><mml:mi>&amp;#x03F5;<\/mml:mi><mml:mo stretchy=\"false\">)<\/mml:mo><\/mml:math> iterations to <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>&amp;#x03F5;<\/mml:mi><\/mml:math>-Nash equilibria. This quadratic speed-up relative to Jain and Watrous' original algorithm sets a new benchmark for computing <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>&amp;#x03F5;<\/mml:mi><\/mml:math>-Nash equilibria in quantum zero-sum games.<\/jats:p>","DOI":"10.22331\/q-2025-05-06-1737","type":"journal-article","created":{"date-parts":[[2025,5,6]],"date-time":"2025-05-06T16:40:36Z","timestamp":1746549636000},"page":"1737","update-policy":"https:\/\/doi.org\/10.22331\/q-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["A Quadratic Speedup in Finding Nash Equilibria of Quantum Zero-Sum Games"],"prefix":"10.22331","volume":"9","author":[{"given":"Francisca","family":"Vasconcelos","sequence":"first","affiliation":[{"name":"UC Berkeley"}]},{"given":"Emmanouil-Vasileios","family":"Vlatakis-Gkaragkounis","sequence":"additional","affiliation":[{"name":"UC Berkeley, UW Madison"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2026-9616","authenticated-orcid":false,"given":"Panayotis","family":"Mertikopoulos","sequence":"additional","affiliation":[{"name":"Univ. Grenoble Alpes, CNRS, Inria, Grenoble INP, LIG, 38000 Grenoble, France"}]},{"given":"Georgios","family":"Piliouras","sequence":"additional","affiliation":[{"name":"Google DeepMind"}]},{"given":"Michael I.","family":"Jordan","sequence":"additional","affiliation":[{"name":"UC Berkeley, Inria Paris"}]}],"member":"9598","published-online":{"date-parts":[[2025,5,6]]},"reference":[{"key":"0","doi-asserted-by":"publisher","unstructured":"John Von Neumann. ``Zur Theorie der Gesellschaftsspiele&apos;&apos;. Mathematische Annalen 100, 295\u2013320 (1928).","DOI":"10.1007\/BF01448847"},{"key":"1","doi-asserted-by":"publisher","unstructured":"John Nash. ``Non-Cooperative Games&apos;&apos;. Annals of Mathematics 54, 286\u2013295 (1951).","DOI":"10.2307\/1969529"},{"key":"2","doi-asserted-by":"publisher","unstructured":"Parvathy S. Pillai and Shrisha Rao. ``Resource Allocation in Cloud Computing Using the Uncertainty Principle of Game Theory&apos;&apos;. 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