TOpological many-body states with ultracold RYDberg atoms

Project Information

TORYD

Grant agreement ID: 863880

DOI

10.3030/863880

EC signature date 19 December 2019

Start date 1 September 2020

End date 31 August 2026

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 900 000,00

EU contribution

€ 1 900 000,00

Coordinated by

SORBONNE UNIVERSITE
France

Periodic Reporting for period 3 - TORYD (TOpological many-body states with ultracold RYDberg atoms)

Reporting period: 2023-09-01 to 2025-02-28

Summary of the context and overall objectives of the project

The overall objective of the project is to explore the dynamics, especially quantum transport, of a many-body quantum system. A specific focus is to develop new tools to go beyond the most commonly explored weakly-interacting regime. The main challenge of this project is to setup a platform based on low-dimensional gases excited to Rydberg states. This important goal will provide a new perspective on the field of quantum simulation.
In more details, we aim at trapping and manipulating ultracold gases of bosons in arbitrary-shaped potentials and then realize two-dimensional, one-dimensional or fully motionally frozen gases. These gases will be excited to a Rydberg state enabling strong interaction between particles. With this tool we expect to observe new many-body topological phases of matter.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

At mid-term of the project, we have successfully developed a new experimental platform allowing us to generate arrays of mesoscopic Bose gases. These gases contains atoms whose motion is fully frozen, a favorable situation to explore the physics of Rydberg superatoms. Moreover, we have shown single-photon excitation of these atoms to Rydberg states thanks to a dedicated UV laser. These two experimental developments represent two key milestones of the project.
In parallel, we also proposed and experimentally confirmed a method to create low dimensional gases of arbitrary density and spin profiles, a central result to explore quantum transport in low-dimensional gases. This new tool have been used to investigate the behaviur of the superfluid fraction of a Bose-Einstein condensate when submitted to a periodic potential. These transport studies enabled us to clarify and experimentally confirm the relationship between the density modulation of a condensate and his superfluid character.
Finally, we also studied the interaction between a condensate and weakly-bound dimers made of the same atoms as the one of the condensate. This may open interesting perspectives on the control of atomic interactions in a Bose gases.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Thanks the demonstration of our ability to engineer highly tunable quantum gases and to Rydberg-excite them with a UV laser in the first half of the project, we will now focus on realizing yet unexplored many-body quantum phases. We will start by realizing independent super-atoms, corresponding to a situation where a single Rydberg excitation is shared by all atoms of a mesoscopic cloud. We will then explore the interaction of two neighbouring clouds and then generalize the problem to arrays of clouds. This will allow us to realize topological many-body states of great interest for quantum simulation. In parallel, we will explore Rydberg-dressing protocols to make bulk gases entering the strongly interacting regime. This will enable the study of many-body quantum transport.