Joint ICTP/Trieste University Condensed Matter Seminars, 16 July, 10:30 L. Chomaz & 11:30 M. Allemand

[CMSP Seminars Secretariat]

Dear colleagues,

you are cordially invited to attend two *Joint ICTP/Trieste University 
Condensed Matter Seminars *with *Lauriane Chomaz *(University of 
Heidelberg, Germany)**and*Maxime Allemand *(Université Paris-Saclay, 
France).  The seminars will take place on *Wednesday 16 July *at *ICTP 
*(Lagrange Lecture Hall), and via Zoom.

You are all most welcome to attend!

Please find all information below.

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*10:30-11:30* Lauriane Chomaz (University of Heidelberg, Germany) 
https://indico.ictp.it/event/11075/

Title: Structural Transition within Two-Dimensional Supersolids of 
Quantum-Stabilized Dipolar Gases

Abstract:
Ultracold atomic gases offer a rich platform for studying quantum 
many-body effects thanks to their high degree of control and tunability. 
Ultracold gases of highly dipolar atoms exhibit unique interaction 
properties leading to striking behaviors at the mean-field level and 
beyond [1]. A decade ago, a universal stabilization mechanism driven by 
quantum fluctuations was discovered in these gases. This mechanism 
prevents the system from collapsing and allows exotic states of matter 
to arise. These include ultradilute quantum droplets, crystallized 
quantum states, and, notably, supersolids, which combine the 
antithetical properties of (super)fluids and solids [2]. After reviewing 
the physics of dipolar gases and their stabilized states, I will present 
our ongoing experimental and theoretical work investigating a structural 
phase transition within two-dimensional supersolids, aiming to better 
understand the richness of the underlying phase diagram.
[1] L. Chomaz et al., "Dipolar physics: A review of experiments with 
magnetic quantum gases,” Rep. Progr. Phys. 86, 026401 (2023).
[2] L. Chomaz, "Quantum-stabilized states in magnetic dipolar quantum 
gases” arXiv:2504.06221 (2025).

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*11:30-12:30* Maxime Allemand (Université Paris-Saclay, Institut 
d’Optique, Palaiseau, France) https://indico.ictp.it/event/11076/

Title: Critical non-Gaussian statistics of an order parameter with 
ultracold lattice bosons

Abstract:
Beyond critical exponents associated to scaling, the universal critical 
properties of second order phase transitions are also characterized by 
the evolution of the entire probability distribution of the order 
parameter across the transition.
I will describe our measurement of the distribution of the amplitude of 
the condensate order parameter across the interaction-induced superfluid 
transition using single-atom-resolved momentum-space detection of a 
(inhomogeneous) lattice Bose gas.
Our measurements align with Landau's phenomenological picture and 
further reveal prominent non-Gaussian fluctuations in the order 
parameter near the transition, distinguished by non-zero and oscillating 
high-order cumulants. Numerical simulations in homogeneous systems show 
similar oscillations exhibiting critical scaling and universality.