The Joint Condensed Matter Seminar (JCMS) series is organised by KTH Royal Insitute of Technology, Nordita, and Stockholm University.
On Monday, May 20th, 2024 from 11 am to 12 am we will host a seminar by Maksym Serbyn from Institute of Science and Technology Austria.
New insights into weak ergodicity breaking from transport and periodic driving
The description of many-particle systems in statistical mechanics rests on the assumption of ergodicity, which is the ability of a system to explore all allowed configurations in phase space. In quantum many-body systems, statistical mechanics predicts the equilibration of a highly excited non-equilibrium state towards a featureless thermal state. In my talk, I will discuss the phenomenon of weak ergodicity breaking, which is relevant for the experimentally realized Rydberg-atom quantum simulator. I will review original studies that suggested the absence of thermalization for a few special initial conditions, related to the existence of non-thermal eigenstates known as quantum many-body scars. In the second part of my talk, I will focus on recent insights from numerical studies of energy transport, which suggest that weak ergodicity breaking is characteristic of a much larger family of eigenstates and reveals superdiffusive transport [1]. Moreover, motivated by recent experiments that implemented periodic driving [2], I will consider the problem of controlling entanglement in interacting quantum systems through periodic driving systems [3]. I will demonstrate that this approach allows for the systematic construction of Floquet models with quantum scars. To conclude, I will discuss open problems and outline promising directions for employing quantum simulators to advance our theoretical understanding of weak ergodicity breaking.
[1] M. Ljubotina, J.-Y. Desaules, M. Serbyn, Z. Papic, Phys. Rev. X 13, 011033 (2023)
[2] D. Bluvstein, et al., Science 371, 1355-1359 (2021)
[3] M. Ljubotina, B. Roos, D. Abanin, M. Serbyn, PRX Quantum 3, 030343 (2022)