Joint ICTP/SISSA Statistical Physics Seminar, 13 February at 11:00am, by M. Mueller

[CMSP Seminars Secretariat]

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Joint ICTP/SISSA Statistical Physics Seminar
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** * * Friday 13 February**2026, 11:00**am ***(CET)** * **
*Euler Lecture Hall **(Leonardo Building)***
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/Zoom: https://zoom.us/meeting/register/2yma2E9GQD-eytFgiOP7Pw/

Speaker:* Markus Mueller *(Paul Scherrer Institut, Villigen, Switzerland)

Title: * On the origin of quantum many-body scars in Rydberg blockade 
systems and beyond **
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Abstract:

  The observation of surprisingly long-lasting oscillations in the 
dynamics of a highly excited states of Rydberg atoms has attracted a lot 
of interest, as they defy the expectation that interacting systems 
should thermalize very quickly. The observed phenomena are reminiscent 
of “scars” that occur in quantum chaotic billiards, where single 
particle eigenfunctions retain traces of periodic classical orbits. 
Meanwhile a large number of models has been found that host one or 
several towers of special (non-thermal) eigenstates whose exactly 
equidistant eigen-energies ensure periodic, non-thermalizing motion.

In this talk I will discuss the unifying principles governing the 
solvable models and show how the (non-solvable) Rydberg chain fits into 
this framework. I further discuss a potential connection of the special 
‘scar’ states of Rydberg chains with single particle scars in quantum 
billiards. I will show that there is a natural classical limit of the 
Rydberg system that features unexpectedly stable periodic orbits, that 
act as islands of parametrically suppressed chaos in the semiclassical 
limit. This opens a new perspective on the limits of quantum chaoticity 
in the many body-context.