维光晶格和原位测量-物 理所BEC研究展望 王如泉 中国科学院物理研究所 第五届全国冷原子物理和量子信息青年 学者学术讨论会 兰州大学2010.8.4
三维光晶格和原位测量-物 理所 BEC研究展望 王如泉 中国科学院物理研究所 第五届全国冷原子物理和量子信息青年 学者学术讨论会 兰州大学 2010. 8. 4
Outline 1. Why is in situ imaging important 2. The bec setup at iop and our in situ imaging plan 3. The 8/Rb-40K-2Na() project at IOP
Outline 1. Why is in situ imaging important 2. The BEC setup at IOP and our in situ imaging plan 3. The 87Rb- 40K- 23Na(6Li) project at IOP
BEC -coherent macroscopic matter wave Vortex in BEC (JILAgroup, 2000 bEC of 87rb (JILAgroup, 1995 Ideal platform for Ultra low temperature quantum physics Matter wave laser (MPQ group, 2000) Matter wave interference (MIT group, 1997)
BEC – coherent macroscopic matter wave lamp laser Vortex in BEC (JILA group, 2000) Matter wave interference (MIT group, 1997) BEC of 87Rb (JILA group, 1995) Ideal platform for Ultra low temperature quantum physics Matter wave laser (MPQ group, 2000)
Quantum simulation of many body physics 强关联多体物理: 什么是量子仿真? 是物理学尚未攻克的难关,又是决定诸 多材料物性的关键(铁磁性,巨磁电阻,Bm-的+H)+2m-1)-∑ 重费米子,高温超导等) 原因 新材料探索 量子计算机: 超导,磁性等 光晶格中的原子气 1.多体波函数,全量子系统 2.非线性系统,无法用微扰论处理 数值仿真 计算资源随系统粒子数指数增长 基本模型研究: Hubbard模型, 解决方案之一: He i sender g模型等 用量子计算机仿真量子系统 Qi Zhou et al, PRL 103, 085701(2009) 特殊的量子计算机-量子仿真器
强关联多体物理： 是物理学尚未攻克的难关，又是决定诸 多材料物性的关键（铁磁性，巨磁电阻， 重费米子，高温超导等） 原因: 1.多体波函数,全量子系统 2.非线性系统，无法用微扰论处理 数值仿真 计算资源随系统粒子数指数增长 解决方案之一： 用量子计算机仿真量子系统 新材料探索: 超导, 磁性等 量子计算机: 光晶格中的原子气 基本模型研究: Hubbard模型, Heisenberg模型等 Quantum simulation of many body physics 什么是量子仿真? 特殊的量子计算机-量子仿真器 Qi Zhou et al, PRL 103, 085701 (2009)
Quantum simulation of many body physics HI BHM ∑(b+He)+∑n(m1-1)-∑ Novel materials Optical Lattices Cuprate Superconductors Alkali atoms Quantum Magnets (Li, Na, K, Rb, Cs) Models Hubbard-Type Models Heisenberg-Type Models Qi Zhou et al, PRL 103, 085701(2009)
Quantum simulation of many body physics Qi Zhou et al, PRL 103, 085701 (2009)
First quantum simulation experiment looks beautiful, but faces a lot of questions Super fluid to Mott insulator phase transition in 3-D optical lattice Greiner M, Mandel O, Esslinger T, Hansch T 3D optical lattice W.& Bloch, Nature 415, 39-44 (2002) Quantum degenerate Bose/Fermi system Lack of a clear diagnostic of how below micro kelvin to identify phases Optical lattice provide periodical potential · Complications due to with no defects coexistence of different phases Atom-atom interaction can be described by a in the same confining potential simple s-wave scattering length Lack of thermometry of the Bose Easily tunable Hubbard Model parameters gas in the optical lattice Artificial toy models: 1D, 2D, spinor, etc
• Quantum degenerate Bose/Fermi system below micro Kelvin • Optical lattice provide periodical potential with no defects • Atom-atom interaction can be described by a simple s-wave scattering length • Easily tunable Hubbard Model parameters • Artificial toy models: 1D, 2D, spinor, etc Super fluid to Mott insulator phase transition in 3-D optical lattice Greiner M., Mandel O., Esslinger T., Hansch T. W. & Bloch I., Nature 415, 39–44 (2002). First quantum simulation experiment looks beautiful, but faces a lot of questions 3D optical lattice • Lack of a clear diagnostic of how to identify phases • Complications due to coexistence of different phases in the same confining potential • Lack of thermometry of the Bose gas in the optical lattice
Time of flight (TOF)imaging CCD
Time of flight (TOF) imaging
TOF imaging of BEC IOP BEG的相变过程 10ms 各向异性膨胀
0ms 10ms 20ms 30ms BEC的相变过程 各向异性膨胀 TOF imaging of BEC @ IOP
Problem with tof measurement T/t=0.57 0.6 0.2 60 40 0 20 2rvd 0 ruD 100 T/t=0.50 0.6 t/U=025 0 1020 Qi Zhou et al, PRL 103, 085701(2009)
Problem with TOF measurement Qi Zhou et al, PRL 103, 085701 (2009)
In-situ imaging corner stone setting experiment by Chin's group at Chicago 产殘 Absorption imaging of density profile of thin layer cold atoms in 2-D optical 4 lattice with a high numerical aperture -40040-40040-40040 Distance(um) Imaging lens. 15° Gemelke, N, Zhang, X, Hung, C.-L& Chin, Nature, 460, 995 (2009)
Gemelke, N., Zhang, X., Hung, C.-L. & Chin, Nature, 460, 995 (2009) Absorption imaging of density profile of thin layer cold atoms in 2-D optical lattice with a high numerical aperture imaging lens. In-situ imaging: corner stone setting experiment by Chin’s group at Chicago