三维光晶格和原位测量.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,三维光晶格和原位测量,-,物理所,BEC,研究展望,1,Outline,Why is in situ imaging important,The BEC setup at IOP and our in situ imaging plan,The,87,Rb-,40,K-,23,Na(,6,Li)project at IOP,2,BEC,coherent macroscopic matter wave,lamp,laser,Vortex in BEC,(JILA group,2000),Matter wave interference,(MIT group,1997),BEC of,87,Rb,(,JILA group,1995,),Ideal platform,for Ultra low,temperature quantum physics,Matter,wave laser,(MPQ group,2000),3,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,:,多体波函数,全量子系统,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),4,Quantum simulation of many,body physics,Qi Zhou et al,PRL,103,085701(2009),5,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,6,Time of flight(TOF)imaging,7,0ms,10ms,20ms,30ms,BEC,的相变过程,各向异性膨胀,TOF imaging of BEC IOP,8,Problem with TOF measurement,Qi Zhou et al,PRL,103,085701(2009),9,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,10,I.Bloch et al,Nature,467,68(2010),I.Bloch,s group,s work to resolve single lattice site,11,Melting of a Mott insulator,12,W.S.Bakr,J.I.Gillen,M.Greiner et al,Nature,462,74(2009),M.Greiner,s group to achieve single lattice resolution,13,Wedding,cake structure of the Mott insulator,W.S.Bakr,M.Greiner et al,Science,329,547(2010),14,What can we achieve with in situ imaging of number density,Tin-Lun Ho and Qi Zhou,，,NATURE PHYSICS,6,131(2009,）,Determine the,superfluid density,temperature,and,chemical potential,of the trapped system with high accuracy,critical for mapping out the phase diagram at finite temperature,Qi Zhou et al,PRL,103,085701(2009),15,Single Chamber BEC IOP,16,Single chamber design vs Double MOT design:advantages and disadvantages,Single chamber,Double MOT,Vacuum system,1 chamber and 1 set of pumping system,2 chambers and 2 sets of pumping system,Laser cooling system,6 laser beams,13 laser beams,Optical access,4 free directions,2D optical lattice,3 free directions,1D optical lattice,No of atoms,1x10,5,(2-5)x10,5,17,Light-Induced Atomic Desorption for loading a Rubidium Magneto-Optical Trap,18,MOT loading at different LED current,19,Fast decay 2s,Slow decay 50s,Vacuum restoring time,20,Quadruple trap,Phys.Rev.A,35,1535(1987),21,Phys.Rev.A,63,031401(2001),Magnetic atom transfer belt,转移线圈,冷原子团,22,Transfer coils geometry,线圈,内半径,mm,外半径,mm,厚度,mm,线,直径,mm,填充率,MOT,30.0,50.0,15.0,1.6,62%,TC,10.0,40.0,15.0,1.6,62%,QUIC,15.0,50.0,10.0,1.6,62%,保持转移方向的磁场梯度为,75G/cm,重力方向,23,Field Plot during the transferring process,24,MOT,BEC,lattice,Imaging lens,CCD camera,CCD camera,Transfer coil 3D lattice and Ultra high resolution in situ imaging,25,Large numerical aperture long working distance objectives,Company,Product specification,Work distance/mm,NA,Zeiss,Epiplan-Neofluar 50 x/0.55 HD DIC M27,9.0,0.55,Olympus,SLMPLN100 x,7.6,0.6,Leica,HCX PL FLUOTAR L 40 x/0.60 CORR,3.3,0.6,Nikon,ELWD 50 x,8.7,0.55,Mitutoyo,M Plan Apo 100 x,G Plan Apo 50 x,6,15.08,0.7,0.5,Group,Objective,M.Greiner,18mm 0.55(to 0.8),I.Bloch,13mm 0.68(Leica),C.Chin,Resolution 3-4um,D.S.Weiss,16mm 0.55,M.Karski,0.29,26,EMCCD camera,Group,CCD,M.Greiner,EMCCD(Andor Ixon DU888),I.Bloch,EMCCD,C.Chin,Not mentioned,D.S.Weiss,EMCCD,M.Karski,EMCCD,Spatial resolved single photon detection,27,Princeton Instrument ProEM:512B_eXcelon,28,异核偶极分子具有,各向异性且长程的偶极,-,偶极相互作用,，是对关联系统研究具有重要意义。,玻色,-,费米混合系统（玻色子，费米子到极性分子）,Quantum degenerate polar molecules,偶极晶体相变，多体偶极量子气，量子信息，超冷化学,量子简并,相干态转化,New.J.Phys,.,11,055049(2009),简并玻色,-,费米混合系统是得到超冷分子的最优手段,超冷分子的重要科学意义,29,基态冷分子制备,偶极分子的各向异性,超冷化学中的量子统计特性,Great achievements and current difficulties,Nature,424,47(2003),Science,301,1510(2003),Phys.Rev.Lett.,100,143201(2008).,Nature Physics,4,622(2008),Phys.Rev.Lett.,100,143201(2008),Science,322,231(2008),Science,327,853(2010),Nature,464,1324,(2010),简并偶极分子实验的关键障碍,铷,-,钾分子偶极矩太小,铷,-,钾分子在超冷碰撞中不稳定,激发态冷分子制备,30,新的原子选择的必要性和优势：,40,K-,23,Na,40,K-,23,Na,具有更大的偶极矩和超冷化学反应的稳定性，是所有可能中的最佳组合,87,Rb-,40,K-,23,Na,（或,6,Li,）混合冷却系统,相对碰撞截面,Rb-Rb,1,K-Rb,2,Li-K,0.2,Li-Li,0.1,Na-Na,0.72,Na-K,？,偶极矩,(Debeye),稳定性,E(cm,-1,),Li-Na,0.56,-328,Li-K,3.6,-534,Li-Rb,4.2,-618,Li-Cs,5.5,-415,Na-K2.8,74.3,K-Rb,0.6,-8.7,K-Cs,1.9,37.8,J.Chem.Phys.122,204302(2005),The,87,Rb-,40,K-,23,Na(,6,Li)project at IOP,31,Vacuum system,23,Na,和,7,Li,同一塞曼减速器和同一套染料激光,转移线圈以实现三维光晶格和原位测量,磁阱,原位测量空间分辨优于,2,微米,32,Laser cooling system,铷原子冷却激光系统,钾原子冷却激光系统,钠原子冷却激光系统,33,Cooling laser for Rb and K,25,o,C下自由运转波长783nm的激光管冷却到-50,o,C得到767nm，0.2nm/,o,C。,困难：冷却到-50C热负载很大且有结露问题，,解决方法：真空隔热和三级制冷。,34,Cooling laser for Lithium,35,cooling laser for Li,36,Complete injection locking,partial injection locking multimode,not injection locking,8mw injection 45,C,7mw injection 45,C,Complete injection locking singlemode 224mw output,FP cavity signal,Optic Spectrometer,37,589nm dye laser for Na cooling,Na,冷却所需的,589nm,激光不能用半导体激光器,成熟的解决方案是染料激光,同时适用于,Na(589nm),和,Li(671nm),的冷却,半导体激光的波长覆盖,38,Zeeman slower,塞曼减速器轴向磁场优化结果,塞曼减速器：,适合于原子量较小的原子，更好的差分真空泵浦,减速器效能,23,Na,和,7,Li,的俘获速度不同,但效能和俘获速度无关,23,Na,和,7,Li,共用塞曼减速器,39,把原子从磁光阱转移到蒸发磁阱,为三维光晶格和原位测量等提供可能,研制重点：,复杂的大电流线圈控制电路,Atomic transferring belt,40,Thermal distribution simulation is very important for high performance magnetic trap,41,强磁场,1000G,磁场稳定性,50mG(50ppm),磁场快速扫描,G/us,快速开启,(ms),B,0,=1007.34G,B=170mG,Phys.Rev.Lett.89,283202(2002),Feshbach coils,研制重点：,强磁场的获得,超高,的磁场稳定性要求,42,Optical lattice,2D,3D,激光器：,IPG,单频光纤激光器,光功率：,50W,束腰,:100,m,研制重点：,激光的稳定性,超高光路稳定性,Nature,453,736(2008),Nature physics,1,23(2005),43,Thank you,for your,attention!,44,