Quantum Systems in Cold Atoms and Superconducting Circuits

Samet Demircan, Paul Stankus, Eden V. Figueroa

An interface between superconducting circuits and atomic systems is the key for distributed quantum computing. We develop a scheme to strongly couple a superconducting microwave resonator to a cold-atom cloud for efficient quantum optical transduction.

Michael Stern

Nicolas Vitrant, Sébastien Garcia, Kilian Müller +1 more

We develop an ultracompact high-resolution imaging system for cold atoms. Its only in-vacuum element is a multimode optical fiber with a diameter of 230 $\ensuremath{\mu}\mathrm{m}$, which simultaneously collects light and guides it out of the vacuum chamber. External adaptive optics allow us to image cold $\mathrm{Rb}$ atoms with approximately 1-$\ensuremath{\mu}\mathrm{m}$ resolution over a $100\ifmmode\times\else\texttimes\fi{}100\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}{\mathrm{m}}^{2}$ field of view. These optics can be easily rearranged to switch between fast absorption imaging and high-sensitivity fluorescence imaging. This system is particularly suited for hybrid quantum-engineering platforms where cold atoms are combined with optical cavities, superconducting circuits, or optomechanical devices restricting optical access.

Nori

R. E. Barfknecht, S. E. Rasmussen, Angela Foerster +1 more

The exotic phenomenon of time-translation-symmetry breaking under periodic driving---one of the main features of the so-called time crystals---has been shown to occur in many-body systems even in clean setups where disorder is absent. In this work, we propose a realization of this effect in few-body systems, both in the context of trapped cold atoms with strong interactions and of a circuit of superconducting qubits. We show how these two models can be treated in a fairly similar way by adopting an effective spin-chain description, to which we apply a simple driving protocol. We focus on the response of the magnetization in the presence of imperfect pulses and interactions, and show how the results can be interpreted, in the cold atomic case, in the context of experiments with trapped bosons and fermions. Furthermore, we provide a set of realistic parameters for the implementation of the superconducting circuit.

Franco Nori