Long Josephson junction in a resonant cavity

Abstract

We present a model to describe an underdamped long Josephson junction coupled to a single-mode electromagnetic cavity, and carry out numerical calculations using this model in various regimes. The coupling may occur through either the electric or the magnetic field of the cavity mode. When a current is injected into the junction, we find that the time-averaged voltage exhibits self-induced resonant steps ͑SIRSs͒ due to coupling between the current in the junction and the electric field of the cavity mode. These steps are similar to those observed and calculated in small Josephson junctions. When a soliton is present in the junction ͑corresponding to a quantum of magnetic flux parallel to the junction plates͒, the SIRSs disappear if the electric field in the cavity is spatially uniform. If the cavity mode has a spatially varying electric field, there is a strong coupling between the soliton and the cavity mode. This coupling causes the soliton to become phase locked to the cavity mode, and produces steplike anomalies on the soliton branch of the I-V characteristics. If the coupling is strong enough, the frequency of the cavity mode is greatly redshifted from its uncoupled value. We present simple geometrical arguments which account for this behavior.

Vortex fractionalization in a Josephson ladder

“…But for λ 2 J = 10, the fluxons are depinned even at I/I c = 0, and the IV curve is very similar to that seen in Ref. [26] for a long junction in the continuum limit. We have also carried out calculations (not shown here) for values of Q J = 1.0, 5.0 and 50.0 for f = 1/2, N = 120 and λ 2 J = 1.0.…”

Süperiletken Durumda Cıva Bazlı Bakır Oksit Katmanlı Süperiletkenin Özgül Kapasitanslarının Tespiti

“…At superconducting state, BEC of Cooper pairs in the CuO 2 layers extends through the all copper oxide layers with the plasma resonance frequency. In other words, superconductivity occurs in connection with a crossover from twodimensional (2D) to 3D transport below the critical transition temperature, T c [8][9][10][11][12]. So that, the perfectly coupled layered mercury-based superconducting material has been proposed to serve as an example of exhibition of 3D-spatial BEC [6].…”

Effects of a resonant cavity on macroscopic quantum tunneling of fluxons in long Josephson junctions

“…We account for the perturbation contribution due to resonant cavity by following Tornes and Stroud 13 and by assuming that the cavity supports a single harmonic oscillator mode which may be represented by the displacement variable q r as…”

“…Earlier studies on the effects of resonant cavity indicate 12,13 that both electric and magnetic fields of the cavity couple to the Josephson junction since the cavity electromagnetic (EM) mode behaves similar to a phonon mode 14 which interacts with the fluxon. The effects of resonant cavity on the fluxon dynamics in LJJ stacks [15][16][17] have been studied both experimentally 18,19 and theoretically.…”