A theorist working on the limits of computation and practical quantum algorithms, combining research on undecidability with the development of software for scientific applications.
University College LondonarXiv / Forum of Mathematics, PiUniversity College LondonCubitt’s work asks both what computation cannot settle and how emerging quantum hardware can be made useful. His spectral-gap research established an undecidability result for a carefully defined class of many-body models. Through Phasecraft, which he cofounded, he also develops quantum algorithms intended for scientific problems on constrained hardware. This combination makes him relevant to readers interested in the gap between mathematical possibility, physical simulation and a usable computing product.
University College LondonarXiv / Forum of Mathematics, PiUniversity College LondonDefining contributions
Work, in context- 2015
The spectral-gap undecidability result
Cubitt, David Pérez-García and Michael M. Wolf showed that deciding whether certain two-dimensional quantum lattice models are gapped or gapless is undecidable. The result concerns a rigorously constructed family of models; it does not make every material’s properties unknowable.
Coauthor of the undecidability proof with David Pérez-García and Michael M. Wolf.
Source-supported recordarXiv / Forum of Mathematics, Pi - 2018
Cofounding Phasecraft
Cubitt cofounded Phasecraft with Ashley Montanaro and John Morton. UCL identifies his role as chief technology officer, connecting his quantum-information research with a company developing algorithms for scientific and industrial uses of quantum computers.
Phasecraft cofounder with Ashley Montanaro and John Morton; CTO role documented by UCL.
Source-supported recordUniversity College LondonUniversity College London
Follow the evidence
3 sourcesPrimary papers, institutional records and attributed announcements. Each source supports the claims linked above.
- University College Londoninstitutional news
UCL spin-out Phasecraft secures $34m Series B to advance quantum computing
Current UCL professor and Phasecraft CTO identification; company focus.
Published 2025-09 · Checked 2026-09-19 - arXiv / Forum of Mathematics, Piprimary research
Undecidability of the Spectral Gap (full version)
Authorship and the precisely scoped undecidability result.
Published 2015-02-16 · Checked 2026-09-19 - University College Londoninstitutional news
UCL spinout developing quantum algorithms raises £13 million
Phasecraft founding, founders and quantum-algorithm remit.
Published 2023-08-16 · Checked 2026-09-19