Quantum many-body theory

Low-temperature atomic systems manifest phenomena that are strikingly different from classical mechanics. Quantum mechanics implies that energy levels are discrete and this is the foundation of the current definition of the second.

Accuracy and precision of optical clocks are entering a regime where not only single-atom quantum mechanics is crucial, but also quantum many-body phenomena play a relevant role. When going beyond mean-field or perturbative theoretical approaches, their study generically requires massively parallel computation on HPC resources.

We are presently investigating:

• the role of ultracold atomic collisions in optical atomic clocks, to improve their accuracy, by means of quantum Monte Carlo methods;

• the dynamics of ultracold atoms in an optical trap, as a means to engineer collective behavior for better clock precision, by means of quantum dynamics libraries such as QuTip.

• The equation of state of trapped ultracold Fermi and Bose gas mixtures

Contact: Gianluca Bertaina

Publications: see here or here

PhD students:

• Jacopo D'Alberto, Università degli Studi di Milano (2021-2024)

Supervisor: Prof. Davide E. Galli. Co-supervisor: Dr. Gianluca Bertaina

• Christian Apostoli, Università degli Studi di Milano (2020-2023)

Supervisor: Prof. Davide E. Galli. Co-supervisor: Dr. Gianluca Bertaina

Theses:

• Quantum Monte Carlo Study of Effective Masses in a Polarized Unitary Fermi Gas

Nitya Cuzzuol, Università degli Studi di Bologna (2022)

Supervisor: Prof. Pierbiagio Pieri. Co-supervisor: Dr. Gianluca Bertaina

• Theoretical modeling and simulation of the generation of spin-squeezed states for quantum enhanced atomic clocks

Andrea Caprotti, Università degli Studi di Milano (2022)

Supervisors: Prof.  Marco G. Genoni, Dr. Gianluca Bertaina. Co-supervisor: Dr. Marco G. Tarallo

• Study of a 2D Bose-Fermi mixture with Quantum Monte Carlo methods

Jacopo D'Alberto, Università degli Studi di Bologna (2021)

Supervisor: Prof. Pierbiagio Pieri, Co-supervisor: Dr. Gianluca Bertaina

• Study of ultracold Rydberg gases via the multiconfiguration time-dependent approach

Christian Apostoli, Università degli Studi di Milano (2020)

Supervisor: Prof. Davide E. Galli. Co-supervisor: Dr. Gianluca Bertaina

Fellowships:

• Generazione di entanglement in atomi freddi accoppiati ad una cavità

Andrea Caprotti, INRiM (2022). Funding source: Q-Clocks QuantERA 2017

Supervisor: Dr. Gianluca Bertaina

Collaborators

Gianluca Bertaina

Former collaborators

Andrea Caprotti

Funding

New 2023! Ministero dell'Università e della Ricerca PRIN "Efficient simulation and design of quantum CONtrol sTRategies for mAny-Body quAntum SystemS" (CONTRABASS)

EU QuantERA Q-Clocks (Levi, Tarallo)

EMPIR USOQS (Levi, Tarallo)