The Dynamic Properties Of Voltage In Josephson Junction

Josephson junction,or superconducting tunnel junction,is one of the most widely used superconducting quantum devices.It was first proposed by the British physicist Josephson in the 1960 s.In recent years,the research on the dynamics of Brownian particles in periodic potentials has received extensive attention.Therefore,as a very good physical device for studying the thermal excitation of particles from the potential well,the Josephson junction has also received the attention of the scientific community.An asymmetric superconducting quantum interference device(SQUID)composed of a superconducting ring and multiple Josephson junctions is essentially a magnetic flux sensor that converts magnetic flux into voltage.The current,voltage,resistance,inductance,magnetic induction,phase difference,etc.in the entire asymmetric superconducting device have a great influence on the stability of the system.Therefore,studying the dynamics of voltage in the entire device can help us better understand the dynamics of classical Brownian particles.First,we introduce the Langevin equation and Fokker-Planck equation,which can specifically describe the dynamical properties of classical Brownian particles and Josephson dynamics,and give the simulation methods for Gaussian white noise and Gaussian colored noise.Then we focus on two nonlinear physical models,a single Josephson junction and a three-junction SQUID ratchet consisting of three Josephson junctions.And its dynamical properties are discussed by its electrical properties through equations.After the introduction of noise disturbances the Langevin equation is obtained which can describe the phase dynamics properties of the whole system.Finally,we studied the transmission phenomenon of voltage in an asymmetric superconducting quantum interference device(SQUID)driven by an external AC current and disturbed by colored noise.The amplitude and frequency of the AC current have a great influence on the whole system.The voltage can be reversed multiple times.Appropriate noise intensity Q and self-correlation time ? can enhance the directional transportation of voltage.There is a set of most suitable system parameters that can maximize the Stokes efficiency of the entire nonlinear system voltage.In addition,we have also studied the transport phenomenon(directional transport)of self-propelled Brownian particles in a confined smooth corrugated channel under the action of alternating lateral forces and colored noise.We found that as the amplitude of the AC transverse force increases,the direction of particle transmission changes several times.For different lateral force amplitudes,x component noise has different effects on the transmission phenomenon.The influence of y component noise on particle movement in the x direction can be ignored.And the average velocity exhibits complex behaviors as the self-driving velocity of particles increases.Figure [24] reference [95]...