Quantum matter
We are investigating how systems of many interacting particles correlate and entangle themselves quantum mechanically, both in and out of equilibrium. A major focus of this research is how electrons behave in novel quantum materials crucial for future technologies, but our work also crosscuts with atomic, molecular and optical physics; high energy physics; and quantum information science.
The understanding the properties of many-body systems comprising particles that behave quantum mechanically and strongly interact with one another is a fundamental challenge of modern physics. In particular, the quantum motion of particles acts to delocalise them in space, while Interactions cause their motion to correlate, for example by clustering or repelling each other. The delicate balance between these tendencies causes striking collective behaviour to emerge in solids like unconventional superconductivity and spin liquidity.
A key part of the challenge in this area is that trying to model exactly more than a few 10’s of quantum particles is infeasible due to the “curse of dimensionality”. For this reason, our work involves developing and applying powerful numerical methods like tensor network theory, variational Monte Carlo and dynamical mean-field theory. Complementary to this we also develop sophisticated analytical techniques and models including topological and geometrical constraints, such as quasi-periodicity, to unravel the rich ways quantum matter can configure itself.
This work has fruitful and surprising overlaps with other areas of physics. The tools and techniques we develop have direct applications to understanding systems of ultra-cold atoms in optical lattices, a synthetic and highly controllable form of quantum matter. Our ability to numerically simulate the properties of quantum matter is deeply connected to quantum information concepts like entanglement and statistical physics techniques like renormalisation group. While new approaches have borrowed well established techniques from high-energy physics such as holography to construct theories of states of quantum matter without conventional quasiparticle excitations.