Colloquium by Professor Wenlan CHEN (Tsinghua University)

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.

You may also like the following events from Department of Physics, CUHK 香港中文大學物理系:

• Next Tuesday, 9th December, 02:30 pm, Seminar by Professor Mingming WU (Cornell University) in Hong Kong

Also check out other Nonprofit events in Hong Kong.