Physics (Internal)

Many body localisation with weak disorder in the quantum east model

This event is part of the Condensed Matter Theory Seminar Series.

The quantum dynamics of closed many body systems has received renewed attention with growing experimental capability to realise these systems. Of particular interest is progress which has established the Many-Body Localised phase as a robust state of matter. These non-thermalizing systems present intriguing dynamics and show quantum systems to be capable of violating the fundamental underlying assumptions of classical statistical mechanics. Generally this is understood to be a disorder driven transition, however the possibility of a many-body localised phase in the absence of static disorder remains an interesting prospect.

We study a kinetically constrained spin model which displays evidence for a disorder-free localisation transition and characterise the different phases of the system by their response to the introduction of static disorder. We find evidence of the existence of a localisation transition for arbitrarily weak disorder at sufficiently low temperatures. This weakly localising phase links the more intensely studied disordered fully localised phase to the disorder free limit. We extract the local integrals of motion, characteristic of the disordered localised phase, and study their fate in the limit of weak disorder. These results connect our understanding of the disordered and disorder free localisation transitions.