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Accueil > Événements > Actualités > Séminaire

Séminaire théorie

Jiri Minar (University of Nottingham, School of Physics and Astronomy)
Localization phenomena and topological properties of atomic lattice gases with long-range interactions
Lieu : Amphithéâtre, maison des Magistères,
le vendredi 17 novembre 2017 à 11h00
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Recent experimental progress in cold atomic gases has allowed for creation of arbitrary lattice geometries at unit filling [1,2] which opens exciting ways for studies of the dynamics of quantum spin Hamiltonians [3]. In this talk I will discuss two examples of dynamics in spin systems with long-range interactions. Firstly, I will discuss the dynamics of Rydberg excitations in an optical tweezer array under the so-called facilitation condition [4]. Here, the presence of positional atomic disorder results in a correlated disorder in the interatomic interaction strengths and drastically affects the facilitation dynamics. To shed light on the role of disorder in a many-body setting we show that here the dynamics is governed by an Anderson-Fock model, i.e., an Anderson model formulated on a lattice with sites corresponding to many-body Fock states. We first consider a one-dimensional atom chain in a limit that is described by a one-dimensional Anderson-Fock model with disorder on every other site, featuring both localized and delocalized states. Next, we consider a situation in which the system maps on a two-dimensional Anderson-Fock model and observe a clear suppression of excitation propagation, which we ascribe to the localization of the many-body wave functions in Hilbert space. With the help of the developed framework we then study the excitation dynamics in the ladder geometry. Secondly, I will describe the topological properties of a two-dimensional atomic lattice gas, where the coupling of the atoms to the radiation field gives rise to dissipation and long-range interactions beyond a simple power law [5]. This has for a consequence energy spectra with one-sided divergences in the Brillouin zone or possible breaking of the standard bulk-boundary relation in topological insulators. We show that under certain conditions, the topological properties, such as the transport of an excitation along the edge of the lattice, remain robust with respect to the presence of lattice defects and dissipation. [1] D. Barredo, S. de Léséleuc et al., Science 354, 1021 (2016) [2] M. Endres, H. Bernien et al., Science aah3752 (2016) [3] H. Labuhn, D. Barredo et al., Nature 534, 667 (2016) [4] M. Marcuzzi, J. Minář et al., Phys. Rev. Lett. 118, 063606 (2017) [5] R. Bettles, J. Minář et al., Phys. Rev. A 96, 041603(R) (2017)


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