We present an improved model for the dissipation and dispersion in an acoustic resonator filled with xenon near its critical temperature . We test the model with acoustic measurements in stirred xenon that have a temperature resolution of . The model includes the frequency-dependent bulk viscosity calculated numerically from renormalization-group theory and it includes critical-point adsorption. Because the density of adsorbed xenon exceeds the critical density, the bulk viscosity’s effect on surface dissipation is reduced, thereby improving the agreement between theory and experiment.

We report the first observation of the impact of mesoscopic fluctuations on the photocount statistics of coherent light scattered in a random medium. A Poisson photocount distribution of the incident light widens and gains additional asymmetry upon transmission through a suspension of small dielectric spheres. The effect is only appreciable when the average number $\overline{n}$ of photocounts becomes comparable or larger than the effective dimensionless conductance $g$ of the sample.

We establish a hierarchical ordering of periodic orbits in a strongly coupled multidimensional Hamiltonian system. Phase space structures can be reconstructed quantitatively from the knowledge of periodic orbits alone. We illustrate our findings for the hydrogen atom in crossed electric and magnetic fields.

We report the experimental observation of the conversion of a phase-invariant nonlinear system into a bistable phase-locked one via rocking [G. J. de Valcárcel and K. Staliunas, Phys. Rev. E 67, 026604 (2003)]. This conversion results in vortices of the phase-invariant system being replaced by phase patterns such as domain walls. A model for the experimental device, a photorefractive oscillator, is given that reproduces the observed behavior.

In addition to the well-known scarring effect of periodic orbits, we show here that homoclinic and heteroclinic orbits, which are cornerstones in the theory of classical chaos, also scar eigenfunctions of classically chaotic systems when associated closed circuits in phase space are properly quantized, thus introducing strong quantum correlations. The corresponding quantization rules are also established. This opens the door for developing computationally tractable methods to calculate eigenstates of chaotic systems.

The largest eigenvalue of the adjacency matrix of networks is a key quantity determining several important dynamical processes on complex networks. Based on this fact, we present a quantitative, objective characterization of the dynamical importance of network nodes and links in terms of their effect on the largest eigenvalue. We show how our characterization of the dynamical importance of nodes can be affected by degree-degree correlations and network community structure. We discuss how our characterization can be used to optimize techniques for controlling certain network dynamical processes and apply our results to real networks.

We studied spark-generated cavitation bubbles inside water drops produced in microgravity. High-speed visualizations disclosed unique effects of the spherical and nearly isolated liquid volume. In particular, (1) toroidally collapsing bubbles generate two liquid jets escaping from the drop, and the “splash jet” discloses a remarkable broadening. (2) Shock waves induce a strong form of secondary cavitation due to the particular shock wave confinement. This feature offers a novel way to estimate integral shock wave energies in isolated volumes. (3) Bubble lifetimes in drops are shorter than in extended volumes in remarkable agreement with herein derived corrective terms for the Rayleigh-Plesset equation.

We report the theoretical and experimental investigation of the effects of mode coupling in a resonant macroscopic quantum device, in the case of a solid-state ring laser. This is achieved by introducing an additional coupling source whose interplay with the already-existing nonlinear effects ensures the coexistence of two counterpropagating cavity modes yielding a rotation-sensitive beat note. The determination of the condition for rotation sensing, both theoretically and experimentally, allows a quantitative study of the role of various mode-coupling mechanisms, in particular, the gain-induced mode coupling. We point out the connection between our work and the theoretical work on mode coupling in superfluid devices. This work opens up the possibility of new types of active rotation sensors.

We consider the modulational instability of nonlinearly interacting two-dimensional waves in deep water, which are described by a pair of two-dimensional coupled nonlinear Schrödinger equations. We derive a nonlinear dispersion relation. The latter is numerically analyzed to obtain the regions and the associated growth rates of the modulational instability. Furthermore, we follow the long term evolution of the latter by means of computer simulations of the governing nonlinear equations and demonstrate the formation of localized coherent wave envelopes. Our results should be useful for understanding the formation and nonlinear propagation characteristics of large-amplitude freak waves in deep water.

We analyze the control of the propagation speed of three wave packets interacting in a medium with quadratic nonlinearity and dispersion. We find analytical expressions for mutually trapped pulses with a common velocity in the form of a three-parameter family of solutions of the three-wave resonant interaction. The stability of these novel parametric solitons is simply related to the value of their common group velocity.

We study the thermal rectification phenomenon in billiard systems with interacting particles. This interaction induces a local dynamical response of the billiard to an external thermodynamic gradient. To explain this dynamical effect we study the steady state of an asymmetric billiard in terms of the particle and energy reflection coefficients. This allows us to obtain expressions for the region in parameter space where large thermal rectifications are expected. Our results are confirmed by extensive numerical simulations.

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a “magnetic atom.” Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric slab waveguide, giving rise to an avoided crossing at near-infrared wavelengths. Our experimental findings are in excellent agreement with theory.

We report on the observation of surface gap solitons found to exist at the interface between uniform and periodic dielectric media with defocusing nonlinearity. We demonstrate strong self-trapping at the edge of a ${\mathrm{LiNbO}}_3$ waveguide array and the formation of staggered surface solitons with propagation constant inside the first photonic band gap. We study the crossover between linear repulsion and nonlinear attraction at the surface, revealing the mechanism of nonlinearity-mediated stabilization of the surface gap modes.

We present the first experimental study of spatial four-wave mixing in photonic lattices, demonstrating universal aspects of nonlinear processes in periodic media, such as engineered phase matching, Bloch-wave folding, and continuous control over the band at which the interaction products emerge.

We report on the first observation of multiple-order bistability due to acoustic radiation pressure in a compliant acoustic cavity formed between a spherical ultrasonic transducer immersed in water and the free liquid surface located at its focus. The hysteretic behavior of the cavity length, observed both with amplitude ramps and frequency sweeps, is accurately described using a one-dimensional model of a compliant Fabry-Pérot resonator assuming the acoustic radiation pressure to be the only coupling between the cavity and the acoustic field.

We study the effect of a turbulent flow of liquid sodium generated in the von Kármán geometry, on the localized field of a magnet placed close to the frontier of the flow. We observe that the field can be transported by the flow on distances larger than its integral length scale. In the most turbulent configurations, the mean value of the field advected at large distance vanishes. However, the rms value of the fluctuations increases linearly with the magnetic Reynolds number. The advected field is strongly intermittent.

By analyzing ultrashort optical pulse propagation in quadratic nonlinear media beyond the slowly varying envelope approximation, we find that the sign and magnitude of self-steepening can be controlled through the wave vector mismatch. As an example of this phenomenon’s impact on ultrashort pulse propagation, we show that it may be used to cancel the propagation effects of group-velocity mismatch. We obtain quantitative agreement between theory, simulations, and experiments.

We demonstrate the existence of stable toroidal dissipative solitons with the inner phase field in the form of rotating spirals, corresponding to vorticity $S=0$, 1, and 2, in the complex Ginzburg-Landau equation with the cubic-quintic nonlinearity. The stable solitons easily self-trap from pulses with embedded vorticity. The stability is corroborated by accurate computation of growth rates for perturbation eigenmodes. The results provide the first example of stable vortex tori in a 3D dissipative medium, as well as the first example of higher-order tori (with $S=2$) in any nonlinear medium. It is found that all stable vortical solitons coexist in a large domain of the parameter space; in smaller regions, there coexist stable solitons with either $S=0$ and $S=1$, or $S=1$ and $S=2$.

We consider a dielectric photonic crystal made of cylindrical holes in a high index matrix. We show that a given finite size photonic crystal can mimic a homogeneous material whose permittivity and permeability are negative. We pay attention to the limitation of the homogeneous medium model and the vital role of the truncation of the crystal.

In this Letter, we introduce a simple metal waveguide array for realizing all-angle wide frequency bandwidth negative refraction from the visible to infrared frequencies. Theoretical analysis from the rigorous coupled-wave theory reveals that the negative coupling constant resulting from the anomalous coupling of guided surface plasmon polariton modes contributes to the negative refraction. The analytical results are confirmed by finite-difference time-domain numerical simulations. Our result provides an alternative way to construct robust all-angle negative refractive materials operating in a wide range of frequency from the near-infrared to the visible range.