Contents - Max-Planck-Institut für Physik komplexer Systeme
Contents - Max-Planck-Institut für Physik komplexer Systeme
Contents - Max-Planck-Institut für Physik komplexer Systeme
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Matter wave interference with complex molecules Incollaborationwiththeexperimentalgroup<br />
aroundM.ArndtattheUniveristyofVienna,wehavebeendevisingnovelnear-fieldinterferenceschemes.<br />
Theyaretargetedtoworkwithparticlesofextremelyhighmass,correspondingtodeBroglewavelengths<br />
inthesub-picometerrange.Thelatestdevelopment,theKapitza-Dirac-Talbot-Lauinterferometer,featuresastandinglightwaveasacentralopticalelementinanear-fielddiffractionsetup.<br />
Italready<br />
establishedthewavenatureofobjectswithmassesexceeding1600protonmassesandsizesexceeding<br />
30˚A.Ourstudiessuggestthatitshouldbepossibletodemonstrateinterferencewithmetalclustersof<br />
massesontheorderof 10 6 atomicmassunits. Sincethecouplingofthecenterofmassmotionto<br />
rotationalandinternaldegreesoffreedommaystarttoplayaroleatthesescales,wearecurrently<br />
studyingwhatconsequencessuchinteractionswillhaveonthevisibilityofinterferencefringes.<br />
Theparadoxofmolecularchirality Itisnotobvious,duetotheparityinvarianceofthemolecular<br />
hamiltonian,howtounderstandfromfirstprincipleswhylargemoleculesoftenshowupasenantiomers,<br />
i.e.inachiralconfigurationwhichcannotbebroughtintocongruencewithitsmirrorimage.Weshowed<br />
thatthisphenomenon,whichisoftenviewedasaparadigmfortheemergenceofclassicalproperties<br />
fromtheunderlyingquantumtheory,canbeexplainedastheresultofspecificenvironmentalinteraction<br />
processes. Wealsoproposedanexperimentfortestingourquantitativepredictions. Itreliesonearlier<br />
ideasofusinglaserstosplitaracemicmolecularbeamintojetsofleft-andright-handedmolecules.<br />
Sincetheseproposalsdonotaccountforthepotentiallydetrimentaleffectofmolecularrotation,weare<br />
currentlyinvestigatingitsconsequencesbyincorporatingtheorientationdynamics.<br />
Inanotherresearchprojectrelatedtotherotationdynamicsofextendedbodieswestudywhetherenvironmentalinteractionscanexplainhowtheclassicalnon-linearEulerequationsofmotionfortheorientation<br />
statecomeabout.Asafirststeptowardsthis,weconstructedaWigner-Weylphasespacerepresentation<br />
oftherotationstatesofanasymmetrictopmolecule.<br />
Incoherentcontrolbymeasurements Coherenttechniquesofquantumcontrolprovetobeincreasingly<br />
difficultwhenappliedtolargequantumsystemssuchaspoly-atomicmolecules. Asawayaroundthis<br />
weareinvestigatinghowtheincoherentdynamicsinducedbycontinuousmonitoringcanprovideamore<br />
robustmeansofsteeringquantumdynamicstowardsdesiredtargetstates.Ourfirstresultsdemonstrate<br />
thepotentialuseofnon-selectivemeasurementsofpositionor,moregenerallyofconfigurationalmolecular<br />
degreesoffreedom,fortheoptimizationoftransitionprobabilities.<br />
Spatialentanglementofmaterialparticles Experimentaldemonstrationsofentanglementbetween<br />
non-interactingmaterialobjectssofaronlyinvolveinternaldegreesoffreedom. Wehavedeveloped<br />
methodsandworkedoutexperimentalscenariosforestablishingnon-localquantumcorrelationsinthe<br />
stateofmotionoffarseparatedfreeparticles.Aspecificexperimentalproposalisbasedonthejudicious<br />
FeshbachdissociationofamolecularBose-Einsteincondensateoffermioniclithiumatoms.Thisadmits<br />
aBelltesttoestablishthattheentangledproperties,thepositionsofeachparticle,aremacroscopically<br />
distinct.<br />
Cooperations<br />
• M.Arndt(UniversitätWien,Austria)andhisexperimentalgrouponinterferencephenomenawith<br />
largemoleculesandmetalclusters<br />
• H.-P.Breuer(UniversitätFreiburg)onquantumMonteCarlomethodsforsolvingMarkovianquantumdynamics<br />
• J.Madroñero(TechnischeUniversitätMünchen)onacomplexscalingapplicationtoopenquantum<br />
systems<br />
• S.Nimmrichter(UniversitätWien,Austria),aco-supervisedPhDstudent,onthetheoryofmolecularnear-fieldinterference<br />
• H.Ulbricht(UniversityofSouthampton,UK)onmolecularinterferenceexperiments,inparticular<br />
theinfluenceofgratingwalldispersionforces<br />
• B.Vacchini(UniversitàdiMilanoandINFNSezionediMilano,Italy)onthederivationandthe<br />
propertiesofthequantumlinearBoltzmannequation<br />
1.8. DepartmentsandResearchGroups 11
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