Synopses & Reviews
This volume reports the recent theoretical and experimental results on the macroscopic quantum coherence of macroscopic systems. Particular attention has been devoted to Josephson devices. The correlation with other atomic and molecular systems exhibiting a macroscopic quantum behavior is also discussed. The volume chapters provide both a historical overview and recent theoretical background on the topic, as well as information on new experimental results relative to the quantum computing area. In particular, observations of quantum behavior in molecular and magnetic systems, small Josephson devices, and quantum dots are also reported and are particularly stimulating in view of the realization of several possible q-bits. The present volume, far from being exhaustive, represents an interesting update of the subject and we hope that it will be a useful tool in stimulating new experiments.
Synopsis
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. Sa
Table of Contents
Preface. Quantum nondemolition measurements of a qubit; D.V. Averin. Bayesian quantum measurement of a single-Cooper-pair qubit; A. Korotkov. 1/f noise in Josephson qubit; E. Paladino, et al. Switching currents and quasi-particle poisoning in the superconducting single electron transistor; P. Agren, et al. Josephson systems for quantum coherence experiments; V. Corato, et al. Solid state analogue of a double slit interferometer; K. Arutyunov, et al. Noise and microwave properties of SET-Transistors; M. Ejrnæs, et al. Use of small tunnel junctions operating at T=0.3K; R. Leoni, et al. A hysteretic single Cooper pair transistor for single shot reading of a charge-qubit; D. Vion, et al. Single Cooper pair electrometer based on a radio-frequency-SQUID scheme; A. Zorin. Possibility of single-electron devices and superconducting coherence; Yu.A. Pashkin, et al. Frequency-locked current of Cooper pairs in superconducting single electron transistor with ohmic resistor; S.V. Lotkhov, et al. Setup for experiment on the supercurrent-phase relation in Bloch transistors status and possible applications; M. Götz, et al. Single-electron transistors in the regime of high conductance; C. Walliser, et al. Superconducting transition-edge sensors for time & energy resolved single-photon counters and for dark matter search; B. Cabrera. Optimization of the hot-electron bolometer and cascade quasiparticle; L. Kuzmin. Noise in refrigerating tunnel junctions and in microbolometers; D.V. Anghel. Nonequilibrium quasiparticles and electron cooling by normal metal-superconductor tunnel junctions; D. Golubev, A. Vasenko. Mesoscopic Josephson junctions coupled to weak coherent fields: an example of reciprocal detection; R. Migliore, A Messina. Dynamics of superconducting interferometers containing pi-junctions; V.K. Kornev, et al. Superconducting current-phase dependance in High-Tc symmetrical bicrystal junction; G.A. Ovsyannikov, et al. Superconducting quantum detector for astronomy and X-ray spectroscopy; A.D. Semenov, et al. Lifetime of even-parity states of a Bloch transistor; J. Männik, et al. Magnetic field dependance of retrapping currents in DC-SQUIDs.S. Saito, et al. Josephson versus Kondo coupling at a quantum dot with superconducting contacts; G. Campagano, et al. Index.