Séminaires futurs

2020

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Lundi 27 Janvier, 13h30, M7 101 (est/ouest)
Tommaso Comparin : A scheme to detect anyons in cold atoms

Résumé: In three dimensions, indistinguishable quantum particles are classified as bosons or fermions based on the symmetry of their many-body wave function under particle exchange. This fundamental distinction is at the basis of peculiar phenomena due to quantum statistics, including Bose-Einstein condensation as a notable example. For systems confined to two dimensions, the fermion/bosons classification is enriched by the existence of another type of particles, named anyons. Early research on anyons was motivated by the fact that some excitations of quantum Hall systems are indeed of anyonic nature. More recently, a revival of interest stemmed from the proposal to use anyons as the building blocks in protocols for topological quantum computing.
In the original systems supporting quantum Hall states, namely electrons in the presence of a magnetic field, protocols for the direct observation of anyons are mainly based on time-dependent interference schemes, but the clear-cut interpretation of their results is still matter of debate. More recently, artificial quantum systems (made for instance of cold atoms, superconducting qubits, or photons) appeared as promising candidates for the realization of quantum Hall states hosting anyonic excitations. In Refs [1] and [2], we devised a detection scheme which is specially suitable for these platforms, as it is mainly based on repeated static measurements of the density profile of the system.
In this talk, I will describe our detection scheme by using the paradigmatic Laughlin wave function as an example. Moreover, I will show how the scheme can be applied to a different system, namely the ground state of an interacting Harper-Hofstadter model. For such system, made by bosonic particles on a lattice with complex hopping phases, we find the ground state by means of the Tree Tensor Network ansatz, which allows us to test the validity of our scheme to detect anyonic excitations [3].

[1] Umucalilar, Macaluso, Comparin, Carusotto, Phys. Rev. Lett. 120, 230403 (2018).
[2] Macaluso, Comparin, Mazza, Carusotto, Phys. Rev. Lett. 123, 266801 (2019).
[3] Macaluso, Comparin, Umucalilar, Gerster, Montangero, Rizzi, Carusotto, Phys. Rev. Research (in press) -- see arXiv:1919:05222.