Search results for " Joseph"
showing 10 items of 80 documents
Running-phase state in a Josephson washboard potential
2005
We investigate the dynamics of the phase variable of an ideal underdamped Josephson junction in switching current experiments. These experiments have provided the first evidence for macroscopic quantum tunneling in large Josephson junctions and are currently used for state read-out of superconducting qubits. We calculate the shape of the resulting macroscopic wavepacket and find that the propagation of the wavepacket long enough after a switching event leads to an average voltage increasing linearly with time.
Flux flow effects in very long Josephson junctions
2000
We report on measurements on very long, L ≃ 30λj, NbAlOxNb underdamped in-line junctions, on which we observed displaced linear slope (DLS) generated by the application of an external magnetic field. We study the behaviour of the branches as a function of the applied magnetic field in terms of both current amplitude and voltage position. The DLS is seen to shift rigidly towards higher voltages when increasing the field, spanning a region roughly centred around the Josephson plasma frequency. We discuss the behaviour of linear branches in terms of one dimensional flux-flow along the extended side of the junction, comparing our data with the results of numerical modeling; from these calculat…
Nonlinear relaxation phenomena in metastable condensed matter systems
2016
Nonlinear relaxation phenomena in three different systems of condensed matter are investigated. (i) First, the phase dynamics in Josephson junctions is analyzed. Specifically, a superconductor-graphene-superconductor (SGS) system exhibits quantum metastable states, and the average escape time from these metastable states in the presence of Gaussian and correlated fluctuations is calculated, accounting for variations in the the noise source intensity and the bias frequency. Moreover, the transient dynamics of a long-overlap Josephson junction (JJ) subject to thermal fluctuations and non-Gaussian noise sources is investigated. Noise induced phenomena are observed, such as the noise enhanced s…
Bi2Sr2Ca2Cu3O10+δ based Josephson junctions and SQUIDs
1996
Josephson junctions and SQUIDs on SrTiO3 bicrystal substrates were prepared from epitaxial Bi2Sr2Ca2Cu3O10+δ thin films with critical temperatures around 95K. The current-voltage characteristics are well described by the resistively and capacitively shunted junction model.I c R n products of 50μV at 77K and 0.7m V at 4.2K have been reached. TheI c (B) dependence is symmetric toB=0 with anI c suppression of 90% in the first minimum. Nevertheless it turns out, that the junctions are inhomogeneous on a μm scale. The flux-voltage transfer function of a SQUID reached 2.7μV/Ф0 at 78K.
Stabilization Effects of Dichotomous Noise on the Lifetime of theSuperconducting State in a Long Josephson Junction
2015
We investigate the superconducting lifetime of a long overdamped current-biased Josephson junction, in the presence of telegraph noise sources. The analysis is performed by randomly choosing the initial condition for the noise source. However, in order to investigate how the initial value of the dichotomous noise affects the phase dynamics, we extend our analysis using two different fixed initial values for the source of random fluctuations. In our study, the phase dynamics of the Josephson junction is analyzed as a function of the noise signal intensity, for different values of the parameters of the system and external driving currents. We find that the mean lifetime of the superconductive…
Thermodynamics of a Phase-Driven Proximity Josephson Junction
2019
We study the thermodynamic properties of a superconductor/normal metal/superconductor Josephson junction {in the short limit}. Owing to the proximity effect, such a junction constitutes a thermodynamic system where {phase difference}, supercurrent, temperature and entropy are thermodynamical variables connected by equations of state. These allow conceiving quasi-static processes that we characterize in terms of heat and work exchanged. Finally, we combine such processes to construct a Josephson-based Otto and Stirling cycles. We study the related performance in both engine and refrigerator operating mode.
Anomalous current in diffusive ferromagnetic Josephson junctions
2017
We demonstrate that in diffusive superconductor/ferromagnet/superconductor (S/F/S) junctions a finite, anomalous Josephson current can flow even at zero phase difference between the S electrodes. The conditions for the observation of this effect are noncoplanar magnetization distribution and a broken magnetization inversion symmetry of the superconducting current. The latter symmetry is intrinsic for the widely used quasiclassical approximation and prevented previous works based on this approximation from obtaining the Josephson anomalous current. We show that this symmetry can be removed by introducing spin-dependent boundary conditions for the quasiclassical equations at the superconducti…
Moraalinen ja metafyysinen paha : vapaus ja pahuus Immanuel Kantin ja F.W.J. Schellingin filosofiassa
2011
Selvitän pro gradu-tutkielmassani saksalaisten idealistien Immanuel Kantin ja F.W.J. Schellingin käsityksiä vapaudesta ja pahuudesta. Esitän että Kant ja Schelling lähestyvät vapautta ja pahaa hyvin erilaisten oletusten pohjalta ja päätyvät siten erilaisiin lopputuloksiin. Toisaalta Kantilla ja Schellingillä on myös yhteinen oletus siinä, että näkevät vapauden tehdä pahaa ilman redukstiota kausaalisiin selityksiin välttämättömäksi ihmisen tahdonvapaudelle. Kantille keskeinen lähtökohta on ihminen ”kahden maailman kansalaisena”. Kant käsittää luonnon, johon ihminenkin kuuluu, täysin kausaalis-mekaanisena kokonaisuutena. Siten ihmisen vapauden täytyy Kantin mukaan perustua sille, että ihmistä…
A chi giovano le lingue segnate?
2020
<div> <p>If much attention has been gained in recent times by sign languages (in particular in the comparison on their nature and on their main peculiar properties also towards a recognition as proper languages, as well as on the challenges they pose to some traditional notions which have been employed so far to describe linguistic phenomena), their possible value from the perspective of inclusiveness deserves at least a brief reflection: the debate on this topic could be moved, from a theoretical point of view, within the search for vehicular languages that conformed humanity’s whole cultural life (in different ways and times), to discuss the possibility that a sign language co…
End-Stage Pancreatic Adenocarcinoma Presenting as a Sister Mary Joseph's Nodule.
2017
[No abstract available]