Quantum materials are governed by how their electrons interact. In metals, such as copper, electrons largely ignore one another, but in quantum materials they have a “social life.” The Theory of Quantum Matter Unit’s main goal is to uncover new laws of physics that explain the interactions of electrons in groups.

Theory of Quantum Matter

More, it has famously been said, is different.

This is particularly true where a large number of quantum obejcts interact, whether these Helium atoms in a superfluid, electrons in a superconductor, cold atoms in an optical trap, or quibits in a quantum computer. In all of these cases, the behaviour of the whole can be very different from the sum of the parts.

The Theory of Quantum Matter group uses a wide range of numerical and analytic techniques to explore these phenomena. Interests represented in the group include novel phases in quantum materials; topological aspects of quantum matter; statistical physics; the application of machine learning to problems in many-body physics; and many-body aspects of quantum computing.

The group has a particular insterest in frustrated magnets - systems torn between one choice and another. The way in which these materials resolve their difficulties has proved a constant source of beautiful, and unexpected, new ideas. We also work closely with experimental physicists, and chemists developing new quantum materials.
You can read more about this work in our Annual Reports, as well as in the papers listed on our Publications page.

Selected Recent Publications

"Witnessing disorder in quantum magnets"
Snigdh Sabharwal, Tokuro Shimokawa, and Nic Shannon
Phys. Rev. Research 7, 023271 (2025)

"Magnon Spectra of Cuprates beyond Spin Wave Theory"
Jiahui Bao, Matthias Gohlke, Jeffrey G. Rau, and Nic Shannon
Phys. Rev. Research 7, L012053(2025)

"Gravitational wave analogues in spin nematics and cold atoms"
Leilee Chojnacki, Rico Pohle, Han Yan, Yutaka Akagi and Nic Shannon
Phys. Rev. B 109, L220407 (2024)

"Solution of SAT Problems with the Adaptive-Bias Quantum Approximate Optimization Algorithm"
Yunlong Yu, Chenfeng Cao, Xiang-Bin Wang, Nic Shannon and Robert Joynt
Phys. Rev. Research 5, 023147 (2023)

"Dynamical scaling as a signature of multiple phase competition in Yb₂Ti₂O₇"
Allen Scheie, Owen Benton, Matthieu Taillefumier, Ludovic D.C. Jaubert, Gabrielle Sala, Niina Jalarvo, Seyed M. Koohpayeh, and Nic Shannon
Phys. Rev. Lett. 129, 217202 (2022)