International Workshop on Superconducting Nano-Electronics Devices

Thisvolumereportsthemajorpartofthescientificcontributionsofthefirstinternational workshoponSuperconductingNano-ElectronicsDevices(SNED)heldinNapoli,Italy,at theendofMay2001. Theaimoftheworkshopwastofocusonrecentexperimentalandtheoreticalresultsin thefieldofsuperconductingnano-electronicsdevices. Itcombinedphysicswithpresent andfuturetechnologicalapplications:bothfundamentalandappliedaspectswerecovered. SpecialemphasiswasgiventoquantumcoherenceandcomputationusingsmallJosephson junctions,noiseinultrasensitivenanodevicesandpossibilitiesofmakinguseofsupercon- ductivityinvariouson-chipdevices. Withtheseattributesandwithrecognizedinvited speakersintheirspecialtiestheworkshopmanagedtobringtogetheracollectionof scientistsfromnearbybutdistinctresearchcommunities. Thiswaytheatmosphereofthe workshopbecameveryopenanddiscussionswerelivelybothduringandoutsidethe sessions. Thisfreshdiscussionhopefullygaveeveryparticipantalotofnewideasfor furtherworkbackintheirhomeinstitutes. OneofthecentraltopicsintheworkshopwastheuseofdifferentJosephsonjunction configurationsasimplementationsofquantumbits. Atthetimeoftheworkshopwewere justwaitingforthesecondwaveofbreakthroughsinthisfield:theresultsemergingfrom theparticipatinglaboratoriesoftheworkshopjustatthetimeofthewritingofthispreface perhapsalsoprovetheusefulnessofourworkshop. Anotherfocuswasonvarioustopicsrelatedtoultrasensativedetectors. Theybring quantumlimitationstoapplications,andmanydeviceconceptsareresultsofunderstanding fundamentalandexcitingphenomenainsuperconductivity. Noiseandon-chipcooling wereexplicitlydiscussedinthedetectorsessionsaswell. ThechoiceofthelocationrecognizestheroleandthetraditionsofNapoliespeciallyin thefieldofmacroscopicquantumcoherence,oneofthemainissuesoftheworkshop. It furtherguaranteedtheparticipantsastimulatingatmosphereatthemeeting. Inconclusion,wewishtothanktheIstitutoItalianopergliStudiFilosofici,theIstituto diCiberneticadelConsiglioNazionaledelleRicerche,theUniversityofJyviiskylii,the IstitutoNazionalediFisicaNucleare,theIstitutoNazionalediFisicadellaMateria,the DipartimentoScienzeFisiche,andtheRettoratodell'UniversitadiNapoli"FedericoII" fortheirsupport. ThanksarealsoduetoAirLiquide,CRY,Nanoway,OxfordInstruments, andRaith. ThisinitiativeisintheframeoftheinternationalactivityofMQC2Association on"MacroscopicQuantumCoherenceandComputing. "WeareindebtedtoC. Granata v vi PREFACE and V. Coratoforscientificassistance,andtoF. Caiazzo,E. DeGrazia,andA. M. Mazzarellafortheirvaluableassistanceinallthetasksconnectedtotheorganizationofthe Workshop. WearealsogratefultoL. Longobardi,A. Monaco,S. Piscitelli,andS. Rombetto forhintsandhelpduringtheWorkshop. ThanksareduetoL. DeFelice,S. Luongo,and V. Sindonifortheorganizationofthesocialevent. J. Pekola B. Ruggiero P. Silvestrini CONTENTS QuantumNondemolitionMeasurementsofaQubit . D. V. Averin BayesianQuantumMeasurementofaSingle-Cooper-PairQubit 11 A. Korotkov lIfNoiseinJosephsonQubits 15 E. Paladino, L. Faoro,G. Falci,and R. Fazio SwitchingCurrentsandQuasi-ParticlePoisoningintheSuperconducting SingleElectronTransistor 25 P. Agren,J. Walter,V. Sch611mann,andD. B. Haviland JosephsonSystemsforQuantumCoherenceExperiments 33 V. Corato,C. Granata, L. Longobardi,M. Russo,B. Ruggiero, andP. Silvestrini SolidStateAnalogueofDoubleSlitInterferometer...43 K. Yu. Arutyunov, T. T. Hongisto,andJ. P. Pekola NoiseandMicrowavePropertiesofSET-Transistors...53 M. Ejrnres,M. T. Savolainen,andJ. Mygind UseofSmallThnnelJunctionsOperatingatT=0. 3K 63 R. Leoni,M. G. Castellano,F. Chiarello,andG. Torrioli AHystericSingleCooperPairTransistorforSingleShotReadingof 73 aCharge-Qubit A. Cottet,D. Vion,P. Joyez,D. Esteve,andM. H. Devoret SingleCooperPairElectrometerBasedonaRadio-Frequency-SQUID Scheme 87 A. B. Zorin vii viii CONTENTS PossibilityofSingle-ElectronDevicesandSuperconductingCoherence 97 Yu. A. Pashkin, Y. Nakamura,T. Yamamoto,andJ. S. Tsai Frequency-LockedCurrentofCooperPairsinSuperconductingSingle ElectronTransistorwithOhmicResistor...105 S. V. Lotk...