Spectral properties and breathing dynamics of a few-body Bose–Bose mixture in a 1D harmonic trap. (10th January 2018)

• Record Type: Journal Article
• Authors: Pyzh, Maxim; Krönke, Sven; Weitenberg, Christof; Schmelcher, Peter
• Is Part Of: New journal of physics. Volume 20:Number 1(2018:Jan.)
• Publication Date: 2018-01-10
• Subjects: collective excitations -- breathing mode -- low-dimensional systems -- few-body systems -- strong interactions -- bosonic mixtures; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aa9cb2
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We investigate a few-body mixture of two bosonic components, each consisting of two particles confined in a quasi one-dimensional harmonic trap. By means of exact diagonalization with a correlated basis approach we obtain the low-energy spectrum and eigenstates for the whole range of repulsive intra- and inter-component interaction strengths. We analyse the eigenvalues as a function of the inter-component coupling, covering hereby all the limiting regimes, and characterize the behaviour in-between these regimes by exploiting the symmetries of the Hamiltonian. Provided with this knowledge we study the breathing dynamics in the linear-response regime by slightly quenching the trap frequency symmetrically for both components. Depending on the choice of interactions strengths, we identify 1 to 3 monopole modes besides the breathing mode of the centre of mass coordinate. For the uncoupled mixture each monopole mode corresponds to the breathing oscillation of a specific relative coordinate. Increasing the inter-component coupling first leads to multi-mode oscillations in each relative coordinate, which turn into single-mode oscillations of the same frequency in the composite-fermionization regime.