FisMat2017 - Submission - View

Abstract's title: Equation of state and self-bound droplet in Rabi-coupled Bose mixtures
Submitting author: Alberto Cappellaro
Affiliation: Università di Padova
Affiliation Address: Dipartimento di Fisica e Astronomia “Galileo Galilei,” Università di Padova, Via Marzolo 8, 35131 Padova, Italy
Country: Italy
Oral presentation/Poster (Author's request): Poster
Other authors and affiliations: Prof. Luca Salasnich (Dipartimento di Fisica e Astronomia “Galileo Galilei,” Università di Padova, Via Marzolo 8, 35131 Padova, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Unità di Padova, Via Marzolo 8, 35131 Padova, Italy, Istituto Nazionale di Ottica (INO) del Consiglio Nazionale delle Ricerche (CNR), Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy) Prof. Tommaso Macrì (Universidade Federal do Rio Grande do Norte, and International Institute of Physics, 59070-405, Natal-RN, Brazil)

Laser induced transitions between internal states of atoms have been playing a fundamental role to manipulate atomic clouds for many decades. In absence of interactions each atom behaves independently and their coherent quantum dynamics is described by the Rabi model.

Since the experimental observation of Bose condensation in dilute gases, static and dynamical properties of multicomponent quantum gases have been extensively investigated. Moreover, at very low temperatures quantum fluctuations crucially affect the equation of state of many-body systems.

Here we study the effects of quantum fluctuations on a Rabi-coupled two-component Bose gas of interacting alkali atoms. The divergent zero-point energy of gapless and gapped elementary excitations of the uniform system is properly regularized obtaining a meaningful analytical expression for the beyond-mean-field equation of state.

In the case of attractive inter-particle interaction we show that the quantum pressure arising from Gaussian fluctuations can prevent the collapse of the mixture with the creation of a self-bound droplet. We characterize the droplet phase and discover an energetic instability above a critical Rabi frequency provoking the evaporation of the droplet. Finally, we suggest an experiment to observe such quantum droplets using Rabi-coupled internal states of potassium-39 atoms.39K atoms.