Recent experiments on large chains of Rydberg atoms [H. Bernien et al., Nature 551, 579 (2017)] have demonstrated the possibility of realizing 1D systems with locally constrained Hilbert spaces, along with some surprising signatures of non-ergodic dynamics, such as persistent oscillations following a quench from the Neel product state. In this talk I will argue that this phenomenon is a manifestation of a "quantum many-body scar", i.e., a concentration of extensively many eigenstates of the system around special many-body states . The special states are analogs of unstable classical periodic orbits in the single-particle quantum billiards. I will present a model based on a single particle hopping on the Hilbert space graph, which quantitatively captures the scarred wave functions up to large systems of 32 atoms. These results suggest that scarred many-body bands give rise to a new universality class of quantum dynamics, which opens up opportunities for creating and manipulating novel states with long-lived coherence in systems that are now amenable to experimental study.
 C. J. Turner, A. A. Michailidis, D. A. Abanin, M. Serbyn and Z. Papić, Nature Phys, 14, 745 (2018).
Zlatko Papic is a Lecturer (i.e. Assistant Professor) in the Theoretical Physics Group at University of Leeds, United Kingdom. He obtained his PhD at Université Paris Sud in 2010. He was a postdoctoral researcher with Ravin Bhatt and Duncan Haldane at Princeton University (2010-2013), and a joint postdoctoral fellow between Perimeter Institute and Institute for Quantum Computing in Waterloo (2013-2015). His research spans condensed matter theory and quantum information, in particular quantum many-body physics, topological phases of matter, fractional quantum Hall effect, graphene, many-body localization and non-equilibrium quantum dynamics.
This seminar is supported with funds from the Korhammer Lecture Series