Research

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About

I am a research scientist at Quantinuum, based in London. Previously, I was a PhD student at the Centrum Wiskunde & Informatica (CWI) and QuSoft, supervised by Harry Buhrman and co-supervised by Florian Speelman. I obtained my PhD from the University of Amsterdam in November 2025.

I am primarily interested in when and how quantum resources can offer advantages over classical resources in computation, using tools from computational complexity. During my PhD, I worked mostly on quantum complexity theory, but also explored quantum query complexity, fault-tolerant benchmarking and quantum property testing.

Email: jordi [dot] weggemans [at] quantinuum [dot] com

Publications and preprints

Check also my Google scholar profile.

• Unconditional and exponentially large violation of classicality
  Marcello Benedetti, Gabriel Marin-Sanchez, Jordi Weggemans, Matthias Rosenkranz and Harry Buhrman
  Published in Nature Communications (2026)
  [arXiv]
• Provable and Verifiable Quantum Advantage in Sample Complexity
  Marcello Benedetti, Harry Buhrman and Jordi Weggemans
  Published in Physical Review Letters 136, 040601 (2026)
  [arXiv]
• Assessing fault-tolerant quantum advantage for k-SAT with structure
  Martijn Brehm and Jordi Weggemans
  Published in Quantum 10, 1975 (2026)
  [arXiv]
• Classical versus quantum queries in quantum PCPs with classical proofs
  Harry Buhrman, François Le Gall and Jordi Weggemans
  [arXiv]
• Finding quantum partial assignments by search-to-decision reductions
  Jordi Weggemans
  [arXiv]
• Permutation tests for quantum state identity
  Harry Buhrman, Dmitry Grinko, Philip Verduyn Lunel and Jordi Weggemans
  Accepted for the non-proceedings track of Theory of Quantum Computation, Communication, and Cryptography (TQC 2024)
  [arXiv]
• Quantum PCPs: on Adaptivity, Multiple Provers and Reductions to Local Hamiltonians
  Harry Buhrman, Jonas Helsen and Jordi Weggemans
  Accepted for the non-proceedings track of Theory of Quantum Computation, Communication, and Cryptography (TQC 2024)
  [arXiv]
  Published in Quantum 9, 1791 (2025)
• Lower Bounds for Unitary Property Testing with Proofs and Advice
  Jordi Weggemans
  [arXiv]
  Published in Quantum 9, 1717 (2025)
• Guidable Local Hamiltonian Problems with Implications to Heuristic Ansatze State Preparation and the Quantum PCP Conjecture
  Jordi Weggemans, Marten Folkertsma and Chris Cade
  Proceedings of the 19th Conference on the Theory of Quantum Computation, Communication, and Cryptography (TQC 2024), LIPIcs 310, Article 10
  [arXiv] [Talk]
• Improved Hardness Results for the Guided Local Hamiltonian Problem
  Chris Cade, Marten Folkertsma, Sevag Gharibian, Ryu Hayakawa, François Le Gall, Tomoyuki Morimae and Jordi Weggemans
  Proceedings of the 50th EATCS International Colloquium on Automata, Languages and Programming (ICALP 2023)
  [arXiv]
• Complexity of the Guided Local Hamiltonian Problem: Improved Parameters and Extension to Excited States
  Chris Cade, Marten Folkertsma and Jordi Weggemans
  Presented at the 26th Annual Conference on Quantum Information Processing (QIP 2023)
  [arXiv] [Talk]
• Quantum Algorithms for Community Detection and their Empirical Run-times
  Chris Cade, Marten Folkertsma, Ido Niessen and Jordi Weggemans
  Published in Quantum Information and Computation 24 (5&6)
  Merged talk at the Quantum Computing Theory in Practice (QCTIP 2022)
  [arXiv]
• Quantifying Grover speed-ups beyond asymptotic analysis
  Chris Cade, Marten Folkertsma, Ido Niesen and Jordi Weggemans
  Accepted talk at the Quantum Computing Theory in Practice (QCTIP 2022)
  Published in Quantum 7, 1133 (2023)
  [arXiv] [Talk]
• Solving correlation clustering with QAOA and a Rydberg qudit system: a full-stack approach
  Jordi Weggemans, Alexander Urech, Alexander Rausch, Robert Spreeuw, Richard Boucherie, Florian Schreck, Kareljan Schoutens, Jiří Minář and Florian Speelman
  Published in Quantum 6, 687 (2022)
  [arXiv] [Talk]
• Tunable critical field in Rashba superconductor thin-films
  A. B. Olde Olthof, J.R. Weggemans, G. Kimbell, J. W. A. Robinson and X. Montiel
  Published in Physical Review B 103, L020504
  [arXiv]

Teaching

• Masters project Martijn Brehm (now PhD student at UvA)
  Role: daily supervisor (2022-2023)
• Quantum Quest
  Role: lecturer (2021, 2023)
• Algorithms & Complexity
  Role: teaching assistant (2022)

Awards

• Lorentz Graduation Prize for Theoretical Physics 2021 (KHMW)

PhD thesis

Quantum versus classical resources in computational complexity
PhD thesis, University of Amsterdam, 2025.
Supervisor: Harry Buhrman. Co-supervisor: Florian Speelman.
ILLC Dissertation Series, DS-2025-09.
[PDF]