We present the design of a superconducting qubit that has circulating currents opposite sign as its two states. The circuit consists three nano-scale aluminum Josephson junctions connected in loop and controlled by magnetic fields. advantages this are it can be made insensitive to background charges substrate, flux states detected with SQUID, manipulated Coupled systems qubits also discussed well sources decoherence.

We present an experimental study of discrete breathers in underdamped Josephson-junction array. Breathers exist under a range dc current biases and temperatures, are detected by measuring voltages. find the maximum allowable bias for breather is proportional to array depinning while minimum seems be related junction retrapping mechanism. have observed that this latter instability leads formation multi-site states also studied domain existence at different values parameters varying temperature.

The aim of this review article is to present recent advances in the theory dynamics modulated phases Frenkel-Kontorova model. This motivated through two specific condensed matter systems: charge-density wave conductors and Josephson junction arrays. presentation tries integrate existing results into perspective equilibrium model, which summarized beginning. issues defectibility, metastability, pinning synchronization are discussed connection with underlying interplay continuum discrete...

The mean first passage time of a Brownian particle from an initial unstable state in metastable system with damping is investigated. analyzed the low to high regime, and role played by parameter studied. We observe noise enhanced stability effect for all states under study values γ curves show behavior vs very close that observed overdamped presence colored as function correlation time.

We propose a simple configuration of one-dimensional parallel array Josephson junctions in which the pinning potential for trapped fluxons lacks inversion symmetry (ratchet potential). This system can be modelised by set non-linear pendula with alternating lenghts and asymmetric harmonic couplings. show, molecular dynamics simulation, that behave as single particles predictions overdamped thermal ratchets easily verified.

We have measured the depinning of trapped kinks in a ratchet potential using fabricated circular array Josephson junctions. Our system consists parallel junctions with alternating cell inductances and areas. compared this other arrays. find experimentally numerically that current depends on direction applied our ring. also properties versus field, such as long period lack reflection symmetry, which we can explain analytically.

We study different architectures for a photonic crystal in the microwave regime based on superconducting transmission lines interrupted by Josephson junctions, both one and two dimensions. A of scattering properties single junction line shows that behaves as perfect mirror when photon frequency matches plasma frequency. generalize our calculations to periodic arrangements demonstrating they can be used tunable band engineering, forming what we call quantum circuit crystal. Two applications...

The influence of lateral vibrations on the stick-slip motion a nanotip elastically pulled flat crystal surface is studied by atomic force microscopy measurements NaCl(001) in ultra-high vacuum. slippage across lattice anticipated at increasing driving amplitude, similarly to what observed presence normal vibrations. This lowers average friction force, as explained Prandtl-Tomlinson model with superimposed finite temperature. Nevertheless, peak values and total energy losses, are expected...

We have investigated the effect of surface disorder on atomic friction in stick-slip dynamical regime a one-dimensional Prandtl-Tomlinson model. find that substrate potential can modify mean slip length and then it changes force system. In particular, is more important at low temperatures close to transition points or high loads. show results for different values temperature, amplitude corrugation potential, dragging velocity, damping. Special care put comparison between regular disordered...

We demonstrate how an exponentially saturating increase of the contact area between a nanoasperity and crystal surface, occurring on time scales governed by Arrhenius equation, is consistent with measurements static friction lateral stiffness model alkali-halide surface at different temperatures in ultrahigh vacuum. The ``contact ageing'' effect attributed to atomic attrition eventually broken thermally activated slip surface. combination two effects also leads regions strengthening...

In this work we study the translocation process of a polymer through nanochannel where time dependent force is acting. Two conceptually different types driving are used: deterministic sinusoidal one and random telegraph noise force. The mean presents interesting resonant minima as function frequency external driving. For computed sizes, scales with length according to power law same exponent for almost all frequencies two forces. dependence rigidity, which accounts persistence molecule,...

The dissipative dynamics of commensurate structures the one-dimensional Frenkel-Kontorova model submitted to dc and ac forces is studied. average velocity varies with external force as a staircase (dynamical mode locking). We characterize unlocking transition from temporal periodicity quasiperiodicity by using standard tools theory dynamical systems. This phenomenologically described generation coherent, time-localized, regularly-distributed increases particle velocities (instantons), which...

We study the thermal and mechanical behaviors of DNA denaturation in frame mesoscopic Peyrard-Bishop-Dauxois model with inclusion solvent interaction. By analyzing melting transition a homogeneous A-T sequence, we are able to set suitable values parameters formation stability bubbles system. Then, focus on case P5 promoter sequence use principal component analysis trajectories extract main information dynamical behavior find that this method gives an excellent agreement previous biological results.

The influence of out-of-plane and in-plane contact vibrations temperature on the friction force acting a sharp tip elastically pulled crystal surface is studied using generalized Prandtl-Tomlinson model. average significantly lowered in frequency range determined by ``washboard'' stick-slip motion viscous damping accompanying motion. An approximately linear relationship between actuation amplitude effective corrugation potential derived case actuation, extending similar conclusion for...

In this work we study the presence of both a minimum and clear oscillations in frequency dependence translocation time polymer described as unidimensional Rouse chain driven by spatially localized oscillating linear potential. The observed mean arise from synchronization between very period external force. We have checked robustness value for changing damping parameter, finding simple relationship correspondent time. function length has been also evaluated, precise ${L}^{2}$ scaling....

This paper considers a Josephson Junction array with the geometry of ladder and anisotropy in couplings. The ground state problem for corresponds to one one-dimensional chiral XY model two-fold field, which allows rigorous characterization phase diagram relevant elementary excitations system. approach equilibrium, we study using Langevin dynamics, shows slow relaxation, typical systems whose energy landscape configuration space consists wealthy metastable states, dynamically disconnected.

Since the original proposal of 1996 by Floria et al. [Europhys. Lett. 36, 539 (1996)] intrinsic localization in Josephson ladders, many efforts have been devoted to theoretical, numerical, and experimental study such dynamical states arrays. Such already produced around 20 papers on subject. In this article we will try review basic aspects physics discrete breathers

A mesoscopic model which allows us to identify and quantify the strength of binding sites in DNA sequences is proposed. The based on Peyrard-Bishop-Dauxois for chain coupled a Brownian particle explores sequence interacting more importantly with open base pairs chain. We apply promoter different organisms. free energy landscape obtained these promoters shows complex structure that strongly connected their biological behavior. analysis method used able differences within genome sequences.

The identification of protein binding sites in promoter sequences is a key problem to understand and control regulation biochemistry biotechnological processes. We use computational method analyze promoters from given genome. Our approach based on physical model at the mesoscopic level protein-DNA interaction influence DNA local conformation dynamics general particle along chain. Following proposed model, joined portion interest, only characterized by its base pair sequence, simulated....

We consider the translocation of a one-dimensional polymer through pore channel helped by motor driven dichotomous noise with time exponential correlation. are interested in study time, mean velocity and stall force system as function driving frequency. find monotonic contrast which shows pronounced maximum at given Interestingly, nonmonotonic behavior presence minimum. The influence spring elastic constant on times velocities is also presented.