Group Seminar via Zoom: Quantum many-body scars and weak ergodicity breaking: from Rydberg atoms to correlated fermions
Jean-Yves Desaules (University of Leeds)
Group meeting via video conference (Zoom)
Tuesday February 23, 2021, 9:00 (MEZ)
Dealing with the unique situation of partial lock downs worldwide and home office solutions at our Institute due to the current spreading of the Covid 19 virus, we are now holding our group seminars and journal clubs via video conference.
This procedure enables us to continue our research, enhance discussions and exchange important information.
Recent experiments on large chains of Rydberg atoms  have demonstrated the possibility of realising one-dimensional, kinetically constrained quantum systems. It was found that such systems exhibit surprising signatures of non-ergodic dynamics, such as robust periodic revivals in global quenches from certain initial states. This weak form of ergodicity breaking has been interpreted as a manifestation of "quantum many-body scars" , i.e., the many-body analogue of unstable classical periodic orbits of a single particle in a chaotic stadium billiard. Scarred many-body eigenstates have been shown to exhibit a range of unusual properties, such as equidistant energy separation, anomalous expectation values of local observables and subthermal entanglement entropy. In this talk, I will review the current theoretical understanding of quantum many-body scars in Rydberg atom chains, highlighting the connections between various theoretical concepts that are being used to describe this phenomenon, including semiclassical dynamics and spectrum generating algebras. In the second part of the talk,
I will present our recent proposal  for an experimental realisation of quantum many-body scars using correlated fermions described by the Fermi-Hubbard model with a magnetic field gradient, arguing that this system could serve as a useful platform to probe the interplay of scars with other forms of ergodicity breaking, such as Stark many-body localisation and Hilbert space fragmentation due to dipole moment symmetry.
 H. Bernien et al., Nature 551, 579 (2017).
 C. J. Turner, A. A. Michailidis, D. A. Abanin, M. Serbyn, Z. Papic, Nat. Phys. 14, 745 (2018).
 J.-Y. Desaules, A. Hudomal, C.Turner, Z. Papic, arXiv:2102.01675.
If you would like to join our group seminars via Zoom, please contact us for more information.