Magnetic Trapping of Atomic Chromiumand Molecular Calcium Monohydride原子铬地磁俘获 分子氢化钙.pdf

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1、MagneticTrappingofAtomicChromiumandMolecularCalciumMonohydrideAthesispresentedbyJonathanDavidWeinsteintoTheDepartmentofPhysicsinpartialfulfillmentoftherequirementsforthedegreeofDoctorofPhilosophyinthesubjectofPhysicsHarvardUniversityCambridge,MassachusettsDec

2、ember2001
c2001-JonathanDavidWeinsteinAllrightsreserved.Tomyparents,ofcourse.ThesisadvisorAuthorJohnMorrisseyDoyleJonathanDavidWeinsteinMagneticTrappingofAtomicChromiumandMolecularCalciumMonohydrideAbstractInthisthesis,Idescribetwotrappingexperiments:themagn

3、etictrappingofatomicchromiumandthemagnetictrappingofmolecularcalciummonohydride.Ex-perimentalworkwithmolecularvanadiummonoxidewillalsobediscussed.Buildingonpreviousworktrappingatomiceuropium,thecalciummonohydrideexperimentwasasuccessfuldemonstrationofthefeas

4、ibilityofmagneticallytrappinganeutralmolecule.Westudiedthedynamicsofourmolecularcoolingandtrappingtechniques.Inaddition,coldmolecule-atominteractionswereexploredintheCaH–Hesystematsub-Kelvintemperatures.VOwasemployedinourfirstattempt,whichfailed,tomagneticall

5、ytrapamolecule.Thereasonsfortheexperiment’sfailurewereinvestigated,andvariouspropertiesofVOmeasuredatlowtemperatures.ThechromiumexperimentwasdesignedtocooltrappedchromiumatomswiththegoalofcreatingacoexistingBose-EinsteincondensateanddegenerateFermigas.Theexp

6、erimentalplanwastousebuffer-gasloadingtomagneticallytraplargenumbersoffermionandbosonisotopesofchromium,andthenuseevaporativecoolingtoincreasethephasespacedensityuntildegeneracywasreached.Althoughwehavenotyetreachedquantumdegeneracy,wewereabletotrapandevapora

7、tivelycoolbothdesiredisotopessimultaneouslyandmeasurerelevantchromium–chromiumcollisionalproperties.Theseresultsilluminatesomeofthebroaderissuesinvolvedwithourcryogenics-basedexperimentaltechniques.ContentsTitlePage....................................iDedica

8、tion....................................iiiAbstract.....................................ivTableofContents................................vCitationstoPreviouslyPublishedWork...................xiA