Topology and symmetries in synthetic fermionic systems

Project Information

TOPSIM

Grant agreement ID: 682629

DOI

10.3030/682629

Project closed

EC signature date 4 October 2016

Start date 1 November 2016

End date 30 April 2023

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 595 000,00

EU contribution

€ 1 595 000,00

Coordinated by

UNIVERSITA DEGLI STUDI DI FIRENZE
Italy

Periodic Reporting for period 5 - TOPSIM (Topology and symmetries in synthetic fermionic systems)

Reporting period: 2022-11-01 to 2023-04-30

Summary of the context and overall objectives of the project

The goal of the TOPSIM project was to address open problems in quantum physics concerning the role of topology and symmetry in fermionic matter. Rather than performing calculations on a classical computer, we have attacked those problems by using the approach of “quantum simulation”, i.e. from an experimental point of view, by taking advantage of novel possibilities of quantum control on synthetic systems formed by ultracold neutral atoms manipulated with laser light. We have investigated the behavior of fermionic matter under strong magnetic fields in order to study the physics of the Hall effect in regimes that were never investigated before. We have also synthesized fermionic systems exhibiting enlarged interaction symmetries beyond the SU(2) symmetry of electrons and evidenced novel phenomena induced by a controlled symmetry breaking, which are believed to be crucial for a class of high-temperature superconductors. With TOPSIM, we have both advanced our understanding of fundamental quantum physics and demonstrated new experimental methods that could be useful to develop novel atom-based quantum technologies, e.g. in the fields of metrology and quantum information processing, with potential benefits for society at large.

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

In TOPSIM we have realized a new experimental platform for the investigation of ultracold atomic systems by using the concept of "synthetic dimensions". In this approach a lattice structure along an effective "extra" dimension is realized by using lasers to couple different internal states of individual atoms. This technology has allowed us to generate large effective magnetic fields for effectively charged particles, with full control on the microscopic model. By using this approach, we have studied the Hall effect – one of the most fundamental effects in solid-state physics, as much as it is still mysterious under many respects – in settings that were previously unaccessed, highlighting the effect of atom-atom interactions on the Hall response and unveiling new universal regimes.

We have also synthesized fermionic systems exhibiting enlarged interaction symmetries beyond the SU(2) symmetry of electrons. By using the same laser manipulation technique that enabled us to create synthetic dimensions, we have realized “synthetic materials” where the atoms exhibit the same behavior that was predicted for the electrons in certain classes of high-temperature superconductors.

We have also worked on new technologies for the manipulation and detection of ultracold quantum states based on the excitation of the atoms with an ultranarrow optical clock transition coupling long-lived electronic states. We have used this approach to probe the properties of quantum states and to control the binding of atoms into molecules, that can have implications for the quantum simulation of exotic superconductor states and even for new metrological applications.

We have also developed new theoretical ideas, based on the TOPSIM approach, that have extended the scope of the project and could lead to the observation of novel states of matter.

All the above results were presented at international conferences and have been made available to the scientific community in open-access publications.

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)

In TOPSIM we have advanced the state of the art in the field of quantum simulation with ultracold atoms. We have perfectioned the “synthetic dimension” approach and, for the first time, successfully combined strong atom-atom interactions and synthetic magnetic fields to probe genuine many-body effects. With this approach we were able to study the Hall response as a function of inter-particle interactions, achieving the strongly interacting regime that had remained elusive since then.

We have also realized new experimental platforms that are promising for the quantum simulation of unconventional superconductivity, and demonstrated new techniques for the manipulation of strongly interacting atoms in different electronic states, which are highly relevant both for the quantum simulation of strongly correlated quantum states, and in a more metrological context for the development of new atomic clocks.

As shown by several theoretical works, the experimental approach we have developed in TOPSIM has the potential to access the physics of strongly correlated states of matter, including the quantum Hall effect, topological magnetic phases and systems with Majorana-like excitations, in a way that, until now, was not possible in other physical systems and in other quantum simulation approaches.

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