BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Zlatko Papic (University of Leeds)
DTSTART:20200610T100000Z
DTEND:20200610T110000Z
DTSTAMP:20260404T131147Z
UID:QM3/5
DESCRIPTION:Title: <a href="https://stable.researchseminars.org/talk/QM3/5
 /">Quantum many-body scars: a new form of weak ergodicity breaking in cons
 trained quantum systems</a>\nby Zlatko Papic (University of Leeds) as part
  of Quantum Matter meets Maths (IST\, Lisbon)\n\n\nAbstract\nRecent experi
 ments on large chains of Rydberg atoms [1] have demonstrated the possibili
 ty of realising one-dimensional\, kinetically constrained quantum systems.
  It was found that such systems exhibit surprising signatures of non-ergod
 ic dynamics\, such as robust periodic revivals in global quenches from cer
 tain initial states. This weak form of ergodicity breaking has been interp
 reted as a manifestation of "quantum many-body scars" [2]\, i.e.\, the man
 y-body analogue of unstable classical periodic orbits of a single particle
  in a chaotic stadium billiard. Scarred many-body eigenstates have been sh
 own to exhibit a range of unusual properties which violate the Eigenstate 
 Thermalisation Hypothesis\, such as equidistant energy separation\, anomal
 ous expectation values of local observables and subthermal entanglement en
 tropy. I will demonstrate that these properties can be understood using a 
 tractable model based on a single particle hopping on the Hilbert space gr
 aph\, which formally captures the idea that scarred eigenstates form a rep
 resentation of a large  spin that is embedded in a thermalising many-body 
 system. I will show that this picture allows to construct a more general f
 amily of scarred models where the fundamental degree of freedom is a quant
 um clock [3]. These results suggest that scarred many-body bands give rise
  to a new universality class of constrained quantum dynamics\, which opens
  up opportunities for creating and manipulating novel states with long-liv
 ed coherence in systems that are now amenable to experimental study.<br>\n
 \n[1] H. Bernien et al.\, Nature 551\, 579 (2017).<br>\n[2] C. J. Turner\,
  A. A. Michailidis\, D. A. Abanin\, M. Serbyn\, Z. Papic\, Nat. Phys. 14\,
  745 (2018).<br>\n[3] Kieran Bull\, Ivar Martin\, and Z. Papic\, Phys. Rev
 . Lett. 123\, 030601 (2019).\n
LOCATION:https://stable.researchseminars.org/talk/QM3/5/
END:VEVENT
END:VCALENDAR