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Visualizzazione post con etichetta impurity. Mostra tutti i post
Visualizzazione post con etichetta impurity. Mostra tutti i post

martedì 20 dicembre 2022

# gst: slow dynamics of a interacting mobile impurity (in a bath of localized particles)

AA << investigate dynamics of a single mobile impurity immersed in a bath of Anderson localized particles and focus on the regime of relatively strong disorder and interactions. In that regime, the dynamics of the system is particularly slow, suggesting, at short times, an occurrence of many-body localization. Considering longer time scales, (AA) show that the latter is a transient effect and that, eventually, the impurity spreads sub-diffusively and induces a gradual delocalization of the Anderson insulator. The phenomenology of the system in the considered regime of slow dynamics includes a sub-diffusive growth of mean square displacement of the impurity, power-law decay of density correlation functions of the Anderson insulator and a power-law growth of entanglement entropy in the system. (AA) observe a similar regime of slow dynamics also when the disorder in the system is replaced by a sufficiently strong quasi-periodic potential. >>

Piotr Sierant, Titas Chanda, Maciej Lewenstein, Jakub Zakrzewski. Slow dynamics of a mobile impurity interacting with an Anderson insulator. arXiv: 2212.07107v1 [cond-mat.dis-nn]. Dec 14, 2022. 

Also

keyword 'particle' | 'quasiparticle' in FonT



keyword 'particelle' in Notes
(quasi-stochastic poetry)


Keywords: gst, particles, impurity, disorder, sub-diffusive growth, transition, entanglement entropy





sabato 27 novembre 2021

# gst: apropos of hybrid nanostructures, the Kondo cloud effects on 'impurities' (inside superconductors).

<< when a metal contains magnetic impurities, conduction electrons can form a screening cloud, which essentially screens the impurity's spin. This physical phenomenon is known as the Kondo effect; thus, the resulting cloud is referred to as a Kondo cloud. >>

<< While the behavior of the Kondo cloud in normal systems is well-understood, its properties in the presence of superconducting materials have not yet been explored in depth. So far, most physicists have believed that the screening of impurity spins in hybrid nanostructures takes place predominantly in the screened, rather than in the unscreened, quantum phase. >>

<< The system we considered exhibits a quantum phase transition when the ground state changes between the Kondo state and the so-called Shiba state, (..) Up to now, it was believed that the screening occurs in the Kondo phase. Quite strikingly, we have however, demonstrated that the Kondo cloud exists also in the unscreened phase. >>  Ireneusz Weymann.

Ingrid Fadelli. Study predicts the behavior of a Kondo cloud in a superconductor. Phys.org. Nov  23, 2021. 


Catalin Pascu Moca, Ireneusz Weymann, et al. Kondo Cloud in a Superconductor.  Phys. Rev. Lett. 127, 186804. Oct 27, 2021.


keywords: gst, nano, hybrid nanostructure, superconductor, transition, impurity, Kondo cloud, Kondo effect