3,605 research outputs found
Exact Moving and Stationary Solutions of a Generalized Discrete Nonlinear Schrodinger Equation
We obtain exact moving and stationary, spatially periodic and localized
solutions of a generalized discrete nonlinear Schr\"odinger equation. More
specifically, we find two different moving periodic wave solutions and a
localized moving pulse solution. We also address the problem of finding exact
stationary solutions and, for a particular case of the model when stationary
solutions can be expressed through the Jacobi elliptic functions, we present a
two-point map from which all possible stationary solutions can be found.
Numerically we demonstrate the generic stability of the stationary pulse
solutions and also the robustness of moving pulses in long-term dynamics.Comment: 22 pages, 7 figures, to appear in J. Phys.
Multiphoton antiresonance
We show that nonlinear response of a quantum oscillator displays antiresonant
dips and resonant peaks with varying frequency of the driving field. The effect
is a consequence of special symmetry and is related to resonant multiphoton
mixing of several pairs of oscillator states at a time. We discuss the
possibility to observe the antiresonance and the associated multiphoton Rabi
oscillations in Josephson junctions.Comment: 4 pages, 3 figures; corrected referenc
Qubit state detection using the quantum Duffing oscillator
We introduce a detection scheme for the state of a qubit, which is based on
resonant few-photon transitions in a driven nonlinear resonator. The latter is
parametrically coupled to the qubit and is used as its detector. Close to the
fundamental resonator frequency, the nonlinear resonator shows sharp resonant
few-photon transitions. Depending on the qubit state, these few-photon
resonances are shifted to different driving frequencies. We show that this
detection scheme offers the advantage of small back action, a large
discrimination power with an enhanced read-out fidelity, and a sufficiently
large measurement efficiency. A realization of this scheme in the form of a
persistent current qubit inductively coupled to a driven SQUID detector in its
nonlinear regime is discussed.Comment: 10 pages, 6 figures. To appear in Phys. Rev.
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