Colloquium by Professor Wenlan CHEN (Tsinghua University)

Name: Colloquium by Professor Wenlan CHEN (Tsinghua University)
Start: 2025-12-12T16:00:00+08:00
End: 2025-12-12T17:00:00+08:00
Location: L2, Science Centre, The Chinese University of Hong Kong

Schedule

Fri Dec 12 2025 at 04:00 pm to 05:00 pm

UTC+08:00

Location

L2, Science Centre, The Chinese University of Hong Kong | Hong Kong, HK

Dissipation is an unavoidable feature of quantum systems, typically associated with decoherence and the modification of quantum correlations. Here we demonstrate that controlled dissipation can serve as a probe for intrinsic correlations in quantum many-body systems. Applying constant dissipation in ultracold atomic systems, we observe universal dissipative dynamics in strongly correlated one-dimensional quantum gases. Specifically, we find a universal stretched-exponential decay of the total particle number, where the stretched exponent measures the anomalous dimension of the spectral function — a critical exponent to characterize strong quantum fluctuations.
In the second part, I will show experimentally that the precise Kibble-Zurek scaling can be retained in the near-critical crossover regime. The Kibble-Zurek scaling reveals the universal dynamics when a system is linearly ramped across a critical point of symmetry-breaking phase transition. In reality, inevitable finite-size effects or symmetry-breaking perturbations can often smear out the critical point and render the phase transition into a smooth crossover. We show that the key ingredient to achieving the precise Kibble-Zurek scaling in the near-critical crossover regime is that the system size and the symmetry-breaking field must be appropriately scaled following the variation of ramping speeds. The experiment is performed in a reconfigurable Rydberg atom array platform, and strengthen the Kibble-Zurek scaling as an increasingly valuable tool for investigating phase transition in quantum simulation platforms.