三维光晶格和原位测量ppt课件

三维光晶格和原位测量-物理所BEC研究展望,1,Outline,WhyisinsituimagingimportantTheBECsetupatIOPandourinsituimagingplanThe87Rb-40K-23Na(6Li)projectatIOP,2,BECcoherentmacroscopicmatterwave,lamp,laser,VortexinBEC(JILAgroup,2000),Matterwaveinterference(MITgroup,1997),BECof87Rb(JILAgroup,1995),IdealplatformforUltralowtemperaturequantumphysics,Matterwavelaser(MPQgroup,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,Quantumsimulationofmanybodyphysics,什么是量子仿真?,特殊的量子计算机-量子仿真器,QiZhouetal,PRL103,085701(2009),4,Quantumsimulationofmanybodyphysics,QiZhouetal,PRL103,085701(2009),5,QuantumdegenerateBose/FermisystembelowmicroKelvinOpticallatticeprovideperiodicalpotentialwithnodefectsAtom-atominteractioncanbedescribedbyasimples-wavescatteringlengthEasilytunableHubbardModelparametersArtificialtoymodels:1D,2D,spinor,etc,SuperfluidtoMottinsulatorphasetransitionin3-DopticallatticeGreinerM.,MandelO.,EsslingerT.,HanschT.W.&BlochI.,Nature415,3944(2002).,Firstquantumsimulationexperimentlooksbeautiful,butfacesalotofquestions,3Dopticallattice,LackofacleardiagnosticofhowtoidentifyphasesComplicationsduetocoexistenceofdifferentphasesinthesameconfiningpotentialLackofthermometryoftheBosegasintheopticallattice,6,Timeofflight(TOF)imaging,7,BEC的相变过程,各向异性膨胀,TOFimagingofBECIOP,8,ProblemwithTOFmeasurement,QiZhouetal,PRL103,085701(2009),9,Gemelke,N.,Zhang,X.,Hung,C.-L.&Chin,Nature,460,995(2009),Absorptionimagingofdensityprofileofthinlayercoldatomsin2-Dopticallatticewithahighnumericalapertureimaginglens.,In-situimaging:cornerstonesettingexperimentbyChinsgroupatChicago,10,I.Blochetal,Nature,467,68(2010),I.Blochsgroupsworktoresolvesinglelatticesite,11,MeltingofaMottinsulator,12,W.S.Bakr,J.I.Gillen,M.Greineretal,Nature,462,74(2009),M.Greinersgrouptoachievesinglelatticeresolution,13,WeddingcakestructureoftheMottinsulator,W.S.Bakr,M.Greineretal,Science,329,547(2010),14,Whatcanweachievewithinsituimagingofnumberdensity,Tin-LunHoandQiZhou，NATUREPHYSICS6,131(2009）,Determinethesuperfluiddensity,temperatureandchemicalpotentialofthetrappedsystemwithhighaccuracy,criticalformappingoutthephasediagramatfinitetemperature,QiZhouetal,PRL103,085701(2009),15,SingleChamberBECIOP,16,SinglechamberdesignvsDoubleMOTdesign:advantagesanddisadvantages,17,Light-InducedAtomicDesorptionforloadingaRubidiumMagneto-OpticalTrap,18,MOTloadingatdifferentLEDcurrent,19,Fastdecay2sSlowdecay50s,Vacuumrestoringtime,20,Quadrupletrap,Phys.Rev.A,35,1535(1987),21,Phys.Rev.A,63,031401(2001),Magneticatomtransferbelt,转移线圈,冷原子团,22,Transfercoilsgeometry,保持转移方向的磁场梯度为75G/cm,重力方向,23,FieldPlotduringthetransferringprocess,24,MOT,BEC,lattice,Imaginglens,CCDcamera,CCDcamera,Transfercoil3DlatticeandUltrahighresolutioninsituimaging,25,Largenumericalaperturelongworkingdistanceobjectives,26,EMCCDcamera,Spatialresolvedsinglephotondetection,27,PrincetonInstrumentProEM: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）,Quantumdegeneratepolarmolecules,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,Greatachievementsandcurrentdifficulties,Nature,424,47(2003),Science,301,1510(2003),Phys.Rev.Lett.100,143201(2008).NaturePhysics4,622(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：40K-23Na,40K-23Na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,87Rb-40K-23Na（或6Li）混合冷却系统,J.Chem.Phys.122,204302(2005),The87Rb-40K-23Na(6Li)projectatIOP,31,Vacuumsystem,23Na和7Li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,Lasercoolingsystem,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,CoolinglaserforRbandK,25oC下自由运转波长783nm的激光管冷却到-50oC得到767nm，0.2nm/oC。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,CoolinglaserforLithium,35,coolinglaserforLi,36,Completeinjectionlocking,partialinjectionlockingmultimode,notinjectionlocking,8mwinjection45C,7mwinjection45C,Completeinjectionlockingsinglemode224mwoutput,FPcavitysignal,OpticSpectrometer,37,589nmdyelaserforNacooling,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,Zeemanslower,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,23Na和7Li的俘获速度不同但效能和俘获速度无关23Na和7Li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,Atomictransferringbelt,40,Thermaldistributionsimulationisveryimportantforhighperformancemagnetictrap,41,强磁场1000G磁场稳定性50mG(50ppm)磁场快速扫描G/us快速开启