ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI Seminarİskender YalçınkayaCzech Technical University in Prague (host: 
Kiss Tamás)Disorder-free localization in quantum walksTuesday, 25 January 
2022, 10:00, Bldg. 1, auditorium, 
https://wigner-hu.zoom.us/j/95461797924?pwd=RDBKcWpoelpadUhoRzhNUnRKai9tZz09  
 Meeting ID: 954 6179 7924  Passcode: 956543The phenomenon of localization 
usually happens due to the existence of disorder in a medium. Nevertheless, 
certain quantum systems allow dynamical localization solely due to the nature 
of internal interactions. We study a discrete-time quantum walker which 
exhibits disorder-free localization. The quantum walker moves on a 
one-dimensional lattice and interacts with on-site spins by coherently 
rotating them around a given axis at each step. Since the spins do not have 
dynamics of their own, the system poses the local spin components along the 
rotation axis as an extensive number of conserved moments. When the 
interaction is weak, the spread of the walker shows subdiffusive behaviour 
having downscaled ballistic tails in the evolving probability distribution at 
intermediate time scales. However, as the interaction gets stronger the 
walker gets exponentially localized in the complete absence of disorder in 
both lattice and initial state. We investigate the relaxation and 
entanglement dynamics of the on-site spins due to their coupling with the 
quantum walker. Surprisingly, we find that even in the delocalized regime, 
entanglement growth and relaxation occur slowly unlike majority of the other 
models displaying a localization transition. Minden érdeklődőt szívesen 
látunk! - Everyone is welcome to attend.Róbert Juhászsem-admin AT szfki.hu