Manipulation and coherence of ultra-cold atoms on a superconducting atom chip

TL;DR

This paper demonstrates the preservation of quantum coherence in ultra-cold 87Rb atoms on a superconducting atom chip, enabling hybrid quantum systems combining cold atoms and superconducting circuits.

Contribution

It introduces a method to load and manipulate large ensembles of ultra-cold atoms near a superconducting circuit while maintaining coherence for seconds.

Findings

Coherence of hyperfine states preserved for several seconds.

Preparation of large thermal and Bose-Einstein condensate ensembles.

Potential for exploring strong collective coupling regimes.

Abstract

The coherence of quantum systems is crucial to quantum information processing. While it has been demonstrated that superconducting qubits can process quantum information at microelectronics rates, it remains a challenge to preserve the coherence and therefore the quantum character of the information in these systems. An alternative is to share the tasks between different quantum platforms, e.g. cold atoms storing the quantum information processed by superconducting circuits. In our experiment, we characterize the coherence of superposition states of 87Rb atoms magnetically trapped on a superconducting atom-chip. We load atoms into a persistent-current trap engineered in the vicinity of an off-resonance coplanar resonator, and observe that the coherence of hyperfine ground states is preserved for several seconds. We show that large ensembles of a million of thermal atoms below 350 nK temperature and pure Bose-Einstein condensates with 3.5 x 10^5 atoms can be prepared and manipulated at the superconducting interface. This opens the path towards the rich dynamics of strong collective coupling regimes.