Abstract
We present a detailed analysis of the dynamical response of ultracold bosonic atoms in a one-dimensional optical lattice subjected to a periodic modulation of the lattice depth. Following the experimental realization by Stöferle et al (2004 Phys. Rev. Lett.92 130403), we study the excitation spectrum of the system as revealed by the response of the total energy as a function of the modulation frequency Ω. By using the Time Evolving Block Decimation algorithm, we are able to simulate one-dimensional systems comparable in size to those in the experiment, with harmonic trapping and across many lattice depths ranging from the Mott-insulator (MI) to the superfluid (SF) regime. Our results produce many of the features seen in the experiment, namely a broad response in the SF regime, and narrow discrete resonances in the MI regime. We identify several signatures of the SF–MI transition that are manifested in the spectrum as it evolves from one limit to the other.
Highlights
DEUTSCHE PHYSIKALISCHE GESELLSCHAFT experiment for the SF regime, a large and broad nonzero response, most strikingly departs from standard theoretical predictions
We study the dynamics of the 1D BHM under lattice modulation and generate excitation spectra for box and harmonic trapping of a large system over numerous lattice depths ranging from the SF to MI regime
Given the comparatively equal strengths of the hopping and interaction terms for the SF regime at U/J = 4, there is no simple picture of either the groundstate or the excitations related to these contributions as there was for the MI regime
Summary
In the experiment [6], effective 1D systems were formed from an anisotropic 3D optical lattice loaded with ultracold bosonic atoms [3]. This is done by adiabatically exposing a BEC to far-off resonance standing wave laser fields in three orthogonal directions forming a 3D optical lattice potential VOL(r) =. The physics of the BHM is governed by the ratio U/J Competition between these two terms results in a transition at temperature T = 0 for a critical ratio (U/J)c from the SF to the MI regime [2, 32]. The presence of trapping and the finite size of a system modifies the nature of the transition, prohibiting it from being sharp and so in line with the experiment [6], we expect the transition to occur gradually somewhere in between these limits [34]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
