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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NonlinearandRelativisticOpticsheadedbyDr.S.Skupin.Thisgroupalsocooperatescloselywiththe<br />
facultyofphysicsandastronomyattheFriedrich-SchillerUniversityinJena,whereDr.S.Skupinholds<br />
aCarlZeissJuniorProfessorshipforComputationalPhotonicssince2009.<br />
NationalandInternational •Themanydifferentnationalandinternationalcollaborationsandcontactsare<br />
listedintheresearchgroupreportsbelow.Furthermore,theinstitutehasasmallbudgetforcollaborations<br />
withexperimentalgroups(p.110).<br />
1.8 DepartmentsandResearchGroups<br />
Division:FiniteSystems<br />
(Head:Prof.Dr.J.-M.Rost)<br />
ThedepartmentFiniteSystemsstudiesthedynamicsoffinitemicroscopicsystemsindifferentenvironments.Oneclassofenvironmentconsistsofsimilarsystemsastheatomormoleculeunderconsideration<br />
(e.g.,clusters,quantumaggregates,ultracoldRydberggases). Stronglightpulsesformanotherquite<br />
universaltypeofenvironment.<br />
Thefundamentalandformalmathematicalaspectsoffinitesystemscoupledtoanenvironmentand<br />
specificallythephenomenonofdecoherencehasbeeninvestigatedbyKlausHornbergerandhisresearch<br />
group.Theeffectofanultracoldenvironmentonatoms,inparticularonmany-bodyRydbergdynamics,<br />
isinthefocusofThomasPohl’sresearchwithhisgrouponComplexDynamicsinUltracoldGases.<br />
TheresearchgroupFiniteSystemswithinthedepartmentconcentratesonclusters(projectleaderUlf<br />
Saalmann),quantumaggregates(projectleaderAlexanderEisfeld)andtheinteractionoffinitesystems<br />
withstrongandshortlightpulses,inspiredbyrapidtechnologicaldevelopmenttowardsultrashortpulses<br />
(attosecondscience)andshortX-raypulses(X-rayFreeElectronLasers).Fruitfulsynergyemergesfrom<br />
therelationbetweenexcitondynamicsintraditionalquantumaggregatesandtheircounterpartinthe<br />
contextofultracoldRydbergcomplexes.<br />
Researchtopics<br />
BasiccouplingmechanismsofshortXUVpulsestomatter Weexplorenon-equilibriummulti-particle<br />
dynamicsofionsandelectronstriggeredbyintensesub-femtosecondlightabsorption. Almostsimultaneousabsorptionofmanyphotonsbymanyboundelectronshasbecomefeasiblewith4thgeneration<br />
lightsourcesandcouldbepossiblewithattosecondsourcesgivenastrongresonantabsorption,e.g.,in<br />
xenon.<br />
Chargemigrationinfinitesystems isauniversalresultofenergyabsorptioninanextendedsystem.<br />
Itsconsequences,apartfromcollectivity,arerarelyexploredascoordinatedmulti-electrondynamicssince<br />
–farfromequilibriumandoftenhappeningonashorttimescale–itisdifficulttoaccess,experimentally<br />
andtheoretically.<br />
IfX-raypulsesirradiateaclusterofatoms,innershellelectronsareremoved(“photo-electrons”),andthe<br />
largespacechargecreated,leadstofieldionizationofatomicouter-shellelectrons.Theseelectronscan<br />
screenafractionoftheionsreducingtheirrepulsionandtherefore,theirmotion,whichiscrucialforsingle<br />
moleculeimaging,animportantfutureapplicationofX-FELradiation.Recentlywehaveinvestigatedan<br />
alternativetoreducetheeffectofthelargespacecharge:Insteadofsupplyingscreeningelectrons,one<br />
canthinkofremovingpositivechargebytransferringelectronsfromlightelements(hydrogen)toheavier<br />
elementssothatthelightbare H + leavethecomplexandreducetherebythespacecharge.Prototypical<br />
systemsareclustersof CH4.<br />
Time-resolvedelectrontransport Onlyrecentlytime-resolvedstudiesinquantumdotshavebecome<br />
possible. Weareinterestedinthetime-dependentresponseofinteractingelectronsinsingleordouble<br />
dotsystemscoupledtocontacts. Inparticularpump-probescenarios–standardtoolsinatomicand<br />
molecularphysics–havebeenhardlyconsideredforquantumtransport. Havingdevelopedespecially<br />
efficientpropagationschemes, wehavefollowedthecoherenttimeevolutionofelectronsindouble<br />
quantumdotsinducedbyfastbias-voltageswitches. Suchdeviceshavethepotentialforacontrolled<br />
8 ScientificWorkanditsOrganizationatthe<strong>Institut</strong>e–anOverview