Rhine Samajdar
Princeton University
Coarsening dynamics and collective excitations in quantum magnets
Location: 1080 Physics Research Building
Faculty Host: Nandini Trivedi
Abstract: Understanding the out-of-equilibrium dynamics of a closed quantum system driven across a quantum phase transition is an important problem with widespread implications for quantum state preparation and adiabatic algorithms. While the quantum Kibble-Zurek mechanism elucidates part of these dynamics, the subsequent and significant coarsening processes lie beyond its scope. Here, we develop a universal description of such coarsening dynamics—and their interplay with the Kibble-Zurek mechanism—in terms of scaling theories. Our comprehensive theoretical framework applies to a diverse set of ramp protocols and encompasses various coarsening scenarios involving both quantum and thermal fluctuations. Moreover, we highlight how such coarsening dynamics can be directly studied in today's “synthetic” quantum many-body systems, including Rydberg atom arrays, and present detailed results on their experimental observation across a (2+1)D Ising quantum phase transition. Interestingly, these dynamics also showcase long-lived oscillations of the order parameter, prompting questions on the emergence of an amplitude mode, which we quantitatively explore. Together, our results provide new insights into emergent collective behavior in strongly correlated systems and nonequilibrium quantum processes.
Bio: Rhine Samajdar is a Princeton Quantum Initiative Postdoctoral Fellow in the Department of Physics and PCTS at Princeton University. His research interests lie at the interface of quantum information science, condensed matter physics, and atomic, molecular, and optical physics. Prior to joining Princeton, he obtained his PhD in Physics from Harvard University in 2022, and his BSc in Physics from the Indian Institute of Science in 2016.
