Séminaire du LPTMS: Alexandru Petrescu *** séminaire exceptionnel ***


11:30 - 12:00

LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay
15 Rue Georges Clemenceau, Orsay, 91405
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Fluxon-based quantum simulation in circuit QED

Alexandru Petrescu (Department of electrical engineering, Princeton University, USA)

Long-lived fluxon excitations can be trapped inside a superinductor ring, which can be realized with a long array of Josephson junctions, one of which offers the input/output path for the magnetic flux [1]. The superinductor ring can be separated into smaller loops by a periodic sequence of Josephson junctions in the quantum regime, thereby allowing fluxons to tunnel between neighboring loops [2]. This model is dual to that of two-leg ladder bosons, which have a rich phase diagram depending on flux and density [3–6]. By tuning the Josephson coupling, and implicitly the tunneling probability amplitude of fluxons, a wide class of 1D tight-binding lattice models may be implemented and populated with a stable number of fluxons. In this context, fluxons are lattice bosons with repulsive interactions. We illustrate this quantum simulation platform by discussing the Su-Schrieffer-Heeger model in the 1-fluxon subspace, which hosts a symmetry-protected topological phase with fractionally charged bound states at the edges [7,8]. This pair of localized edge states could be used to implement a superconducting qubit increasingly decoupled from decoherence mechanisms.

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