三维光晶格和原位测量幻灯片课件.ppt

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1、三维光晶格和原位测量BEC coherent macroscopic matter wavelamplaserVortex in BEC(JILAgroup,2000)Matter wave interference(MITgroup,1997)BEC of 87Rb(JILAgroup,1995)IdealplatformforUltralowtemperaturequantumphysicsMatter wave laser(MPQgroup,2000)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

2、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Quantumsimulationofmanybodyphysics什么是量子仿真?特殊的量子计算机特殊的量子计算机-量子仿真器量子仿真器QiZhouetal,PRL103,085701(2009)QuantumsimulationofmanybodyphysicsQiZhouetal,PRL103,085701(2009)QuantumdegenerateBose/Fermi

3、systembelowmicroKelvinOpticallatticeprovideperiodicalpotentialwithnodefectsAtom-atominteractioncanbedescribedbyasimples-wavescatteringlengthEasilytunableHubbardModelparametersArtificialtoymodels:1D,2D,spinor,etcSuper fluid to Mott insulator phase transition in 3-D optical latticeGreinerM.,MandelO.,E

4、sslingerT.,HanschT.W.&BlochI.,Nature415,3944(2002).Firstquantumsimulationexperimentlooksbeautiful,butfacesalotofquestions3D optical latticeLackofacleardiagnosticofhowtoidentifyphasesComplicationsduetocoexistenceofdifferentphasesinthesameconfiningpotentialLackofthermometryoftheBosegasintheopticallatt

5、iceTime of flight(TOF)imaging0ms10ms20ms30msBEC的相变过程各向异性膨胀TOFimagingofBECIOPProblemwithTOFmeasurementQiZhouetal,PRL103,085701(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 opticallattice with a high numerical apertu

6、re imaging lens.In-situimaging:cornerstonesettingexperimentbyChinsgroupatChicagoI.Blochetal,Nature,467,68(2010)I.BlochsgroupsworktoresolvesinglelatticesiteMeltingofaMottinsulatorW.S.Bakr,J.I.Gillen,M.Greineretal,Nature,462,74(2009)M.GreinersgrouptoachievesinglelatticeresolutionWeddingcakestructureof

7、theMottinsulatorW.S.Bakr,M.Greineretal,Science,329,547(2010)WhatcanweachievewithinsituimagingofnumberdensityTin-LunHoandQiZhou，NATURE PHYSICS 6,131(2009）Determinethesuperfluid density,temperatureandchemical potential ofthetrappedsystemwithhighaccuracy,criticalformappingoutthephasediagramatfinitetemp

8、eratureQiZhouetal,PRL103,085701(2009)SingleChamberBECIOPSingle chamber design vs Double MOT design:advantages and disadvantagesSingle chamberDouble MOTVacuum system1 chamber and 1 set of pumping system2 chambers and 2 sets of pumping systemLaser cooling system6 laser beams13 laser beamsOptical acces

9、s4 free directions2D optical lattice3 free directions 1D optical latticeNo of atoms1x105(2-5)x105Light-Induced Atomic Desorption for loading a Rubidium Magneto-Optical TrapMOTloadingatdifferentLEDcurrentFastdecay2sSlowdecay50sVacuumrestoringtimeQuadrupletrapPhys.Rev.A,35,1535(1987)Phys.Rev.A,63,0314

10、01(2001)Magneticatomtransferbelt转移线圈冷原子团Transfercoilsgeometry线圈内半径mm外半径mm厚度mm线直径mm填充率MOT30.050.015.01.662%TC10.040.015.01.662%QUIC15.050.010.01.662%保持转移方向的磁场梯度为75G/cm重力方向FieldPlotduringthetransferringprocessMOTBEClatticeImaginglensCCDcameraCCDcameraTransfercoil3DlatticeandUltrahighresolutioninsituim

11、agingLargenumericalaperturelongworkingdistanceobjectivesCompanyProduct specification Work distance/mmNAZeissEpiplan-Neofluar 50 x/0.55 HD DIC M279.00.55OlympusSLMPLN100 x7.60.6LeicaHCX PL FLUOTAR L 40 x/0.60 CORR3.30.6NikonELWD 50 x8.70.55MitutoyoM Plan Apo 100 xG Plan Apo 50 x615.080.70.5Group Obje

12、ctiveM.Greiner18mm 0.55(to 0.8)I.Bloch13mm 0.68(Leica)C.ChinResolution 3-4umD.S.Weiss16mm 0.55M.Karski0.29EMCCDcameraGroup CCDM.GreinerEMCCD(Andor Ixon DU888)I.BlochEMCCDC.ChinNot mentionedD.S.WeissEMCCDM.KarskiEMCCDSpatialresolvedsinglephotondetectionPrincetonInstrumentProEM:512B_eXcelon异核偶极分子具有各向异

13、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GreatachievementsandcurrentdifficultiesNature,424,47(2003),Science,301,1510(2003),Phys.Rev.Let

14、t.100,143201(2008).Nature Physics4,622(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简并偶极分子实验的关键障碍1.铷-钾分子偶极矩太小2.铷-钾分子在超冷碰撞中不稳定激发态冷分子制备新的原子选择的必要性和优势：40K-23Na40K-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）混合冷却系统相对碰撞截面Rb-Rb

15、1K-Rb2Li-K0.2Li-Li0.1Na-Na0.72Na-K？偶极矩(Debeye)稳定性E(cm-1)Li-Na0.56-328Li-K3.6-534Li-Rb4.2-618Li-Cs5.5-415Na-K2.874.3K-Rb0.6-8.7K-Cs1.937.8J.Chem.Phys.122,204302(2005)The87Rb-40K-23Na(6Li)projectatIOP30Vacuumsystem23Na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31Lasercoolingsystem铷原子冷却激光系统钾原子冷

16、却激光系统钠原子冷却激光系统32Cooling laser for Rb and K25oC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。Cooling laser for Lithium cooling laser for Li Completeinjectionlockingpartialinjectionlockingmultimodenotinjectionlocking8mwinjection45C7mwinjection45CCompleteinjectionlocking

17、singlemode224mwoutputFP cavity signalOptic Spectrometer589nmdyelaserforNacoolingNa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：研制重点：复杂的大电流线圈控制电

18、路AtomictransferringbeltThermal distribution simulation is very important for high performance magnetic trap强磁场1000G磁场稳定性50mG(50ppm)磁场快速扫描G/us快速开启(ms)B0=1007.34G,B=170mGPhys.Rev.Lett.89,283202(2002)Feshbachcoils研制重点：研制重点：强磁场的获得超高的磁场稳定性要求Opticallattice2D3D激光器：IPG单频光纤激光器光功率：50W束腰:100m研制重点：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)42Thank you for your attention!此课件下载可自行编辑修改，仅供参考！此课件下载可自行编辑修改，仅供参考！感谢您的支持，我们努力做得更好！谢谢感谢您的支持，我们努力做得更好！谢谢