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TT: Fachverband Tiefe Temperaturen
TT 21: Focus Session: Quantum Dynamics of Kinetically Constrained Many-Body Systems (joint session TT/DY)
TT 21.8: Talk
Tuesday, April 2, 2019, 12:45–13:00, H2
Apparent slow dynamics in the ergodic phase of a driven many-body localized system without extensive conserved quantities — •Talía Lezama Mergold Love1, Soumya Bera2, and Jens H. Bardarson1,3 — 1Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany — 2Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India — 3Department of Physics, KTH Royal Institute of Technology, Stockholm, 106 91 Sweden
One of the distinguishing features of the ergodic phase in systems exhibiting many-body localization (MBL) is a slowing down of the dynamics as they approach the MBL transition. Using a fast Walsh-Hadamard transform, we numerically study the former scenario in a Floquet model with no global conservation laws. In this model, the ergodic-MBL transition can be tuned by the disorder strength within a region of the frequency-amplitude space. Similarly to models with conserved quantities, our data is consistent with a subballistic spread of entanglement and a stretched-exponential decay of an autocorrelation function, with their associated exponents reflecting slow dynamics near the transition for a fixed system size. However, with access to larger system sizes, we find a clear flow of the exponents towards faster dynamics. We further observe examples of non-monotonic dependence of the exponents with time, consistent with the slow dynamics being a crossover phenomena with a localized critical point.