Related papers: New Method to Improve the Accelerating Gradient of…
We study quench detection in superconducting accelerator cavities cooled with He-II. A rigorous mathematical formula is derived to localize the quench position from dynamical data over a finite time interval at a second sound detector.
Quench of superconducting radio-frequency cavities frequently leads to the lowered quality factor Q0, which had been attributed to the additional trapped magnetic flux. Here we demonstrate that the origin of this magnetic flux is purely…
Solid-state quantum coherent devices are quickly progressing. Superconducting circuits, for instance, have already been used to demonstrate prototype quantum processors comprising a few tens of quantum bits. This development also revealed…
Driving a conventional superconductor with an appropriately tuned classical electromagnetic field can lead to an enhancement of superconductivity via a redistribution of the quasiparticles into a more favorable non-equilibrium distribution…
Three prototype 6-cell superconducting cavities for acceleration in the velocity range of 0.40 to 0.53 times the speed of light have been fabricated. The quality factor (Q) of the first prototype cavity was above 1E10 for accelerating…
This paper introduces a machine learning-aided fault detection and isolation method applied to the case study of quench identification at the European X-Ray Free-Electron Laser. The plant utilizes 800 superconducting radio-frequency…
Local dissipation of RF power in superconducting radio frequency cavities create so called hot spots, primary precursors of cavity quench driven by either thermal or magnetic instability. These hot spots are detected by a temperature…
Superconducting RF cavities are used in particle accelerators to provide energy to the particle beam. Such cavities are mostly fabricated in niobium and often operated in superfluid helium. One of their limits of operation is the appearance…
Differences in the confinement of electrons and holes in quantum dots are shown to profoundly impact the magnitude of scattering with acoustic phonons in materials where crystal deformation shifts the conduction and valence band in the same…
We employ an equivalent-circuit model of a multi-cell cavity to explore its time-dependent behavior in order to understand differences between the multi-cell model and the commonly-used model of a single-cell resonator. Furthermore, we…
We consider a two-dimensional electron gas interacting with a quantized cavity mode. We find that the coupling between the electrons and the photons in the cavity enhances the superconducting gap. Crucially, all terms in the Peierls phase…
A novel method is proposed to measure the Purcell effect by observing the current through a semiconductor quantum dot embedded inside a microcavity. The stationary current is shown to be altered if one varies the cavity length. For the…
In quantum sensing and metrology, an important class of measurement is the continuous linear measurement, in which the detector is coupled to the system of interest linearly and continuously in time. One key aspect involved is the quantum…
We consider the quantum measurement properties of a driven cavity with a Kerr-type nonlinearity which is used to amplify a dispersively coupled input signal. Focusing on an operating regime which is near a bifurcation point, we derive…
Conditional measurements on the undriven mode of a two-mode cavity QED system prepare a coherent superposition of ground states which generate quantum beats. The continuous system drive induces decoherence through the phase interruptions…
Plastic tuning of multicell superconducting accelerating cavities is crucial in the development cycle of cavities for particle accelerators. Cavities must meet stringent requirements regarding the operating mode frequency, field flatness,…
A novel approach to detect anomalies in superconducting radio-frequency cavities is presented, based on the parity space method with the goal to detect quenches and distinguish them from other anomalies. The model-based parity space method…
We have investigated theoretically the conductance of a Normal-Superconductor point-contact in the tunnel limit and analyzed the quantum interference effects originating from the scattering of quasiparticles by point-like defects.…
Vacuum fluctuations of quantum fields provide an unavoidable environment for any quantum system coupled to it. We study the interplay between boundary conditions and acceleration in determining decoherence of a two-level Unruh-DeWitt…
Quench spectroscopy is a relatively new method which enables the investigation of spectral properties of many-body quantum systems by monitoring the out-of-equilibrium dynamics of real-space observables after a quench. So far the approach…