报告题目：Dynamics of a Bose-Einstein condensates inside a driven optical lattice
报告人：Dr. Eric Michon
主持人：武海斌教授
时间：7月10日（周二）下午2:00
地点：理科大楼A814会议室
主办单位：精密光谱科学与技术国家重点实验室
报告摘要：
The subject of this talk is study of the dynamics of a Bose Einstein condensate in a phase modulated optical lattice. The first experiment I will present is based on the sudden shift of the phase of the lattice that induces a displacement of a few tenth of nm. This experiment allowed us to develop a new method to calibrate the depth of the lattice using the period of the micro-oscillation of the BEC chain triggered by the phase shift. There is a bijection between the depth of the lattice and the oscillation period giving the period the ideal profile to be a calibration method [1]. The dynamic of the oscillation shows tunnel effect between adjacent wells of the lattice. We have been able to measure directly the tunneling time which is the delay between an atoms packet which passed through a potential barrier by tunnel effect and a packet of atoms which continued its oscillation [2]. The last part of the talk presents a study of the dynamics of the BEC inside a lattice which phase is modulated with a sine function. When we modulate with low frequencies the phase of the lattice, the tunnel rate between adjacent wells is renormalized. The dynamical transition of an atomic Bose–Einstein condensate from a spatially periodic state to a staggered state with alternating sign in its wavefunction is experimentally studied using a one dimensional phase modulated optical lattice [3]. We observe the crossover from quantum to thermal fluctuations as the triggering mechanism for the nucleation of staggered states. In good quantitative agreement with numerical simulations based on the truncated Wigner method, we experimentally investigate how the nucleation time varies with the renormalized tunneling rate, the atomic density, and the driving frequency. The effective inverted energy band in the driven lattice is identified as the key ingredient for the transition and the possibility to nucleate staggered states from interband excitations as reported experimentally.
[1] C. Cabrera-Gutiérrez, E. Michon, V. Brunaud, T. Kawalec, A. Fortun, M. Arnal, J. Billy, and D.
Guéry-Odelin, Phys. Rev. A 97, 043617 (2018)
[2] A. Fortun, C. Cabrera-Gutiérrez, G. Condon, E. Michon, J. Billy, and D. Guéry-Odelin, Phys. Rev.
Lett. 117, 010401 (2016).
[3] E. Michon, C .Cabrera-Gutiérrez, A. Fortun, M. Berger, M. Arnal, V. Brunaud, J. Billy, C. Petitjean,
P. Schlagheck, and D. Guéry-Odelin, New J. Phys. 20 053035 (2018).
报告人简介
Eric Michon
Laboratoire Collisions Agrégats Réactivité (LCAR)
Bat. 3R1b4 - 118 route de Narbonne
31062 TOULOUSE France
Phd thesis (October 2015 - September 2018 )
Title: Out of equilibrium dynamics of Bose-Einstein condensates in driven optical lattices
Supervisors: Prof. David Guéry-Odelin, Dr. Juliette Billy
Laboratory: LCAR University Paul Sabatier, Toulouse
Education
Master, Université Paul Sabatier, Toulouse, Condensed Matter Physics. 2013 -2015
Internship M1, Measurement of Tune-Out Wavelength of 7Li, Mathias Büchner, LCAR, Toulouse2014
Internship M2, Prodcution and caracterization of a 87Rb BEC, David Guéry-Odelin, LCAR, Toulouse 2015