Seminars
Entanglement in Non-Classical Spin States and a Quantum Hall Cylinder with Ultracold Dysprosium
July 21st, 2021 TANISH SATOOR Laboratoire Kastler Brossel, Collège de France, CNRS,
ENS-PSL University, Sorbonne Université

Each week we present and discuss publications out of the world of atomic, molecular and optical (AMO) physics. Topics are of experimental and theoretical relevance. This week, Tanish Satoor will present:

Paper: Entanglement in non-classical spin states and a quantum Hall cylinder with ultracold dysprosium (https://arxiv.org/pdf/2104.14389.pdf)

Abstract:

In this talk, I will present two recent projects from our dysprosium quantum gas experiment. Firstly, we describe a study of entanglement [1] within non-classical spin states of the electronic ground state spin J=8 of dysprosium. This spin can formally be viewed as a set of 2J qubits symmetric upon exchange. To access entanglement properties, we partition the spin by optically coupling it to an excited state J’=J-1, which removes a pair of qubits in a state defined by the light polarization. For the well-known W and Schrödinger cat states, we measure the concurrence of the extracted qubit pair, which quantifies its non-classical character. We also directly demonstrate entanglement between the 14- and 2-qubit subsystems via an increase in entropy upon partition. In a complementary set of experiments, we prepare these states in the excited level J’=J+1 and interpret spontaneous emission as a loss of a qubit pair in a random state.

In contrast, the second part of the talk is based on exploiting the spin J=8 as a synthetic dimension to engineer artificial gauge fields. After a brief recap of our realisation of a Quantum hall system in a 2D ribbon geometry [2], we focus on our recent scheme to extend this work to a cylindrical geometry, using laser couplings to engineer a periodic synthetic dimension. We validate the protocol by characterising states adiabatically prepared in the flat ground band, and present a scheme to quantify the observed transverse linear response. Finally, we present preliminary results demonstrating geometric pumping and links to Laughlin’s original thought experiment.

[1]: T Satoor, A Fabre, JB Bouhiron, A Evrard, R Lopes & S Nascimbene,arXiv:2104.14389 (2021)
[2]: T Chalopin, T Satoor, A Evrard, V Makhalov, J Dalibard, R Lopes & S Nascimbene, Nature Physics 16, 1017–1021 (2020)

ZOOM LINK

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Journal Club, July 21, 2021, 12:00. Online (Zoom)

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