Dynamics of Fluxon Lattice in Two Coupled Josephson Junctions

We study theoretically the dynamics of a fluxon Lattice (FL) in two coupled Josephson junctions. We show that when the velocity of the moving FL exceeds certain values $(V_{a,b})$, sharp resonances arise in the system which are related to the excitation of the optical and acoustic collective modes. In the interval $(V_a, V_b)$ a reconstruction of the FL occurs. We also establish that one can excite localized nonlinear distortions (dislocations) which may propagate through the FL and carry an arbitrary magnetic flux.Comment: 4 pages, 3 figures, corected typo

Gauging Nonlinear Supersymmetry

Coset methods are used to construct the action describing the dynamics associated with the spontaneous breaking of the local supersymmetries. The resulting action is an invariant form of the Einstein-Hilbert action, which in addition to the gravitational vierbein, also includes a massive gravitino field. Invariant interactions with matter and gauge fields are also constructed. The effective Lagrangian describing processes involving the emission or absorption of a single light gravitino is analyzed.Comment: 20 pages, no figure

Carrier drift velocity and edge magnetoplasmons in graphene

We investigate electron dynamics at the graphene edge by studying the propagation of collective edge magnetoplasmon (EMP) excitations. By timing the travel of narrow wave-packets on picosecond time scales around exfoliated samples, we find chiral propagation with low attenuation at a velocity which is quantized on Hall plateaus. We extract the carrier drift contribution from the EMP propagation and find it to be slightly less than the Fermi velocity, as expected for an abrupt edge. We also extract the characteristic length for Coulomb interaction at the edge and find it to be smaller than for soft, depletion edge systems.Comment: 5 pages, 3 figures of main text and 6 pages, 6 figures of supplemental materia