Observation of electro-activated localized structures in broad area VCSELs

We demonstrate experimentally the electro-activation of a localized optical structure in a coherently driven broad-area vertical-cavity surface-emitting laser (VCSEL) operated below threshold. Control is achieved by electro-optically steering a writing beam through a pre-programmable switch based on a photorefractive funnel waveguide.Comment: 5 Figure

Observation of Fermi-Pasta-Ulam-Tsingou Recurrence and Its Exact Dynamics

One of the most controversial phenomena in nonlinear dynamics is the reappearance of initial conditions. Celebrated as the Fermi-Pasta-Ulam-Tsingou problem, the attempt to understand how these recurrences form during the complex evolution that leads to equilibrium has deeply influenced the entire development of nonlinear science. The enigma is rendered even more intriguing by the fact that integrable models predict recurrence as exact solutions, but the difficulties involved in upholding integrability for a sufficiently long dynamic has not allowed a quantitative experimental validation. In natural processes, coupling with the environment rapidly leads to thermalization, and finding nonlinear multimodal systems presenting multiple returns is a long-standing open challenge. Here, we report the observation of more than three Fermi-Pasta-Ulam-Tsingou recurrences for nonlinear optical spatial waves and demonstrate the control of the recurrent behavior through the phase and amplitude of the initial field. The recurrence period and phase shift are found to be in remarkable agreement with the exact recurrent solution of the nonlinear Schrödinger equation, while the recurrent behavior disappears as integrability is lost. These results identify the origin of the recurrence in the integrability of the underlying dynamics and allow us to achieve one of the basic aspirations of nonlinear dynamics: the reconstruction, after several return cycles, of the exact initial condition of the system, ultimately proving that the complex evolution can be accurately predicted in experimental conditions

Optical supercavitation in soft-matter

We investigate theoretically, numerically and experimentally nonlinear optical waves in an absorbing out-of-equilibrium colloidal material at the gelification transition. At sufficiently high optical intensity, absorption is frustrated and light propagates into the medium. The process is mediated by the formation of a matter-shock wave due to optically induced thermodiffusion, and largely resembles the mechanism of hydrodynamical supercavitation, as it is accompanied by a dynamic phase-transition region between the beam and the absorbing material.Comment: 4 pages, 5 figures, revised version: corrected typos and reference

Nonlinear Gamow vectors in nonlocal optical propagation

Shock waves dominate in a wide variety of fields in physics dealing with nonlinear phenomena, nevertheless the description of their evolution is not resolved for the entire dynamics. Here we propose an analytical method based on Gamow vectors, which belong to irreversible quantum mechanics. We theoretically and experimentally show the appearance of these decaying states during shock evolution allowing to describe the whole wave propagation. These results open new ways to the control of extreme nonlinear regimes such as supercontinuum generation or in the analogies of fundamental physical theories

Topological control of extreme waves

From optics to hydrodynamics, shock and rogue waves are widespread. Although they appear as distinct phenomena, transitions between extreme waves are allowed. However, these have never been experimentally observed because control strategies are still missing. We introduce the new concept of topological control based on the one-to-one correspondence between the number of wave packet oscillating phases and the genus of toroidal surfaces associated with the nonlinear Schrödinger equation solutions through Riemann theta functions. We demonstrate the concept experimentally by reporting observations of supervised transitions between waves with different genera. Considering the box problem in a focusing photorefractive medium, we tailor the time-dependent nonlinearity and dispersion to explore each region in the state diagram of the nonlinear wave propagation. Our result is the first realization of topological control of nonlinear waves. This new technique casts light on shock and rogue waves generation and can be extended to other nonlinear phenomena

molecular and chromosomal characterization of repeated and single copy dna sequences in the genome of dasypyrum villosum

Restriction fragment length polymorphism of ribosomal DNA repeated unit and single-copy DNA fragments and chromosomal distribution of a highly repeated sequence, have been studied to assess molecular markers and the extent of their heterogeneity in Dasypyrum villosum. Substantial variation has been found for the length of the intergenic spacer of ribosomal genes clustered in different alleles at Nor- VI locus of heterozygous individuals, but not within the cluster of rDNA of homozygous individuals. After Southern blots and hybridization to an intergenic spacer probe, each cluster of rDNA was detected as a single band with at least four variants differing for the number of 130 bp subrepeats in the intergenic spacer. One recombinant plasmid contained a 2270 bp DNA insert from the D. villosum genome that upon Sph I restriction endonuclease digestion was cleaved in three 380 bp repeat elements and one 1090 bp fragment. When Southern blots of Sph 1 digested D. villosum DNAs of different genotypes were hybridized to the 32P-labelled 380 bp repeat, a distinct ladder consisting of multiples of a basic repeat unit of about 380 bp in length was revealed on autoradiograms. The in situ hybridization of the 3H-labelled 380 bp repeat element showed that one chromosome pair (7V) was not labelled. In the other pairs, silver grains remained clustered at or near the telomeres. Dot-blot hybridization analysis of DNAs from a range of diploid, tetraploid, and hexaploid Triticeae species indicated that the 380 bp repeated element was a specific feature of the D. villosum genome. Other cloned DNA sequences of D. villosum showed a large restriction length polymorphism and one was located on V chromosomes

One-Two Dimensional Nonlinear Pulse Interaction

The peculiar intergrability of the Davey-Stewartson equation allows us to find analytically solutions describing the simultaneous formation and interaction of one-dimensional and two-dimensional localized coherent structures. The predicted phenomenology allows us to address the issue of interaction of solitons of different dimensionality that may serve as a starting point for the understanding of hybrido-dimensional collisions recently observed in nonlinear optical media.Comment: 11 pages + 4 figure

Route to nonlocality and observation of accessible solitons

We develop a general theory of spatial solitons in a liquid crystalline medium exhibiting a nonlinearity with an arbitrary degree of effective nonlocality. The model accounts the observability of "accessible solitons" and establishes an important link with parametric solitons.Comment: 4 pages, 2 figure

Bell's theorem without inequalities and without probabilities for two observers

A proof of Bell's theorem using two maximally entangled states of two qubits is presented. It exhibits a similar logical structure to Hardy's argument of ``nonlocality without inequalities''. However, it works for 100% of the runs of a certain experiment. Therefore, it can also be viewed as a Greenberger-Horne-Zeilinger-like proof involving only two spacelike separated regions.Comment: REVTeX, 4 page