2016/06/08 by Roberto Monaco, R. Monaco
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Fluxon #Josephson effect #Magnetic field #Mechanics #Physics #Physics of Superconductivity and Magnetism #Pi Josephson junction #Quantum and electron transport phenomena #Quantum mechanics #Quantum tunnelling #Superconductivity #Tunnel junction #Vortex #cond-mat.supr-con
paper · pdf · doi:10.1088/0953-8984/28/44/445702
published as Journal of Physics: Condensed Matter, Volume:28 , Issue:44, Article Number: 445702 (2016) · 18 pages, 9 figures
arxiv created 2016/06/08 · openalex publication_date 2016/09/08 · arxiv updated 2016/09/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Long Josephson tunnel junctions are non-linear transmission lines that allow propagation of current vortices (fluxons) and electromagnetic waves and are used in various applications within superconductive electronics. Recently, the Josephson vortex has been proposed as a new superconducting qubit. We describe a simple method to create a double-well potential for an individual fluxon trapped in a long elliptic annular Josephson tunnel junction characterized by an intrinsic non-uniform width. The distance between the potential wells and the height of the inter-well potential barrier are controlled by the strength of an in-plane magnetic field. The manipulation of the vortex states can be achieved by applying a proper current ramp across the junction. The read-out of the state is accomplished by measuring the vortex depinning current in a small magnetic field. An accurate one-dimensional sine-Gordon model for this strongly non-linear system is presented, from which we calculate the position-dependent fluxon rest-mass, its Hamiltonian density and the corresponding trajectories in the phase space. We examine the dependence of the potential properties on the annulus eccentricity and its electrical parameters and address the requirements for observing quantum-mechanical effects, as discrete energy levels and tunneling, in this two-state system.