Search results for "Josep"

Inducing Strong Non-Linearities in a Phonon Trapping Quartz Bulk Acoustic Wave Resonator Coupled to a Superconducting Quantum Interference Device

2018

International audience; A quartz Bulk Acoustic Wave resonator is designed to coherently trap phonons in such a way that they are well confined and immune to suspension losses so they exhibit extremely high acoustic Q-factors at low temperature, with Q × f products of order 10¹⁸ Hz. In this work we couple such a resonator to a Superconducting Quantum Interference Device (SQUID) amplifier and investigate effects in the strong signal regime. Both parallel and series connection topologies of the system are investigated. The study reveals significant non-Duffing response that is associated with the nonlinear characteristics of Josephson junctions. The nonlinearity provides quasi-periodic structu…

Spin torques and magnetic texture dynamics driven by the supercurrent in superconductor/ferromagnet structures

2018

We introduce the general formalism to describe spin torques induced by the supercurrents injected from the adjacent superconducting electrodes into the spin-textured ferromagnets. By considering the adiabatic limit for the equal-spin superconducting correlations in the ferromagnet we show that the supercurrent can generate both the field-like spin transfer torque and the spin-orbital torque. These dissipationless spin torques are expressed through the current-induced corrections to the effective field derived from the system energy. The general formalism is applied to show that the supercurrent can either shift or move the magnetic domain walls depending on their structure and the type of s…

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…

RELAXATION PHENOMENA IN CLASSICAL AND QUANTUM SYSTEMS

2012

Relaxation phenomena in three different classical and quantum systems are investigated. First, the role of multiplicative and additive noise in a classical metastable system is analyzed. The mean lifetime of the metastable state shows a nonmonotonicbehavior with a maximum as a function of both the additive and multiplicative noise intensities. In the second system, the simultaneous action of thermal and non-Gaussian noise on the dynamics of an overdamped point Josephson junction is studied. The effect of a Lévy noise generated by a Cauchy–Lorentz distribution on the mean lifetime of the superconductive metastable state, in the presence of a periodic driving, is investigated. We find resonan…

Lifetime of the superconductive state in long Josephson junctions in presence of non-Gaussian noise sources

2012

The effects of Lévy noise sources on the transient dynamics of long Josephson junctions (LJJ) are investigated in the presence of both a periodical current signal and a noise source with Gaussian, Cauchy-Lorentz or Levy-Smirnov probability distributions. In particular, by numerically integrating the Sine-Gordon equation, the mean escape time (MET) from the superconductive metastable state is obtained as a function both of the frequency of the periodical force and amplitude of the noise signal. We find resonant activation (RA) and noise enhanced stability (NES). Significative changes in RA and NES are observed by using Lévy noise sources with different statistics. MET is also studied as a fu…

θ0 thermal Josephson junction

2017

We predict the thermal counterpart of the anomalous Josephson effect in superconductor/ferromagnet/superconductor junctions with noncoplanar magnetic texture. The heat current through the junction is shown to have the phase-sensitive interference component proportional to cos(θ−θ0), where θ is the Josephson phase difference and θ0 is the texture-dependent phase shift. In the generic trilayer magnetic structure with the spin-filtering tunnel barrier θ0 is determined by the spin chirality of magnetic configuration and can be considered as the direct manifestation of the energy transport with participation of spin-triplet Cooper pairs. In case of the ideal spin filter the phase shift is shown …

Nb based Josephson junctions subgap transport phenomena

2005

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…