Beecroft Building, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Roderich Moessner, Max Planck Institute for the Physics of Complex Systems
Abstract
We present a simple theory accounting for two central observations in a recent experiment on quantum coarsening and collective dynamics on a programmable quantum simulator [T. Manovitz et al., Nature 638, 86 (2025)]: an apparent speeding up of the coarsening process as the phase transition is approached; and persistent oscillations of the order parameter after quenches within the ordered phase. Our theory, based on the Hamiltonian structure of the equations of motion in the classical limit of the quantum model, finds a speeding up already deep within the ordered phase, with subsequent slowing down as the domain wall tension vanishes upon approaching the critical line. Further, the oscillations are captured within a mean-field treatment of the order parameter field. For quenches within the ordered phase, small spatially-varying fluctuations in the initial mean-field lead to a remarkable long-time effect, wherein the system dynamically destroys its long-range order and has to coarsen to re-establish it. We term this phenomenon symmetry re-breaking, as the resulting late-time magnetization can have a sign opposite to the initial magnetization.
Federico Balducci, Anushya Chandran, Roderich Moessner, arXiv:2507.17386
Professor Moessner will be giving a second technical lecture as part of the Lamb Lecture series on Monday 24th November. Please find more details here.
As part of the Lamb Lecture series. Professor Moessner is also giving a public lecture and a second technical lecture, Professor Moessner will be giving two technical lectures:
- 24th Nov 2025: Topological physics as censor, and as microscope
- 24th Nov 2025: Public Lecture - Fractionalisation: Dividing the Indivisible