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5.0

Apr 4, 2021
04/21

Apr 4, 2021
by
CLAUDIO CONTI (furb3tto)

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Tappi per il telaio Hypermotard 950. Sono stati progettati per non aver bisogno di supporti, quando li posizionate sul piano di stampa ricordatevi di tenere il logo non a contatto con il letto di stampa.

Topics: thingiverse, Machine Tools, stl

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10.0

Mar 15, 2021
03/21

Mar 15, 2021
by
CLAUDIO CONTI (furb3tto)

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Non avendo trovato nulla che mi piacesse a livello di design, ho progettato questo case per ascoltare la musica liquida. Incorpora un amplificatore e monitor 5" touch. Ho poi aggiunto un termostato e una ventola per quando ci saranno giornate molto calde considerando che io non lo spengo mai ma metto in pausa la canzone così dopo pochi minuti anche il display va in standby. Ho inserito alcune foto con i rendering iniziali e il progetto terminato. ho inserito anche un file di testo con...

Topics: stl, Audio, thingiverse

8
8.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Kou-Bin Hong; Chun-Yan Lin; Tsu-Chi Chang; Wei-Hsuan Liang; Ying-Yu Lai; Chien-Ming Wu; You-Lin Chuang; Tien-Chang Lu; Claudio Conti; Ray-Kuang Lee

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The use of geometrical constraints opens many new perspectives in photonics and in fundamental studies of nonlinear waves. By implementing surface structures in vertical cavity surface emitting lasers as manifolds for curved space, we experimentally study the impacts of geometrical constraints on nonlinear wave localization. We observe localized waves pinned to the maximal curvature in an elliptical-ring, and confirm the reduction in the localization length of waves by measuring near and far...

Topics: Optics, Physics

Source: http://arxiv.org/abs/1704.08026

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94

Jun 30, 2018
06/18

Jun 30, 2018
by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We present a complete and consistent quantum theory of generalised X waves with orbital angular momentum (OAM) in dispersive media. We show that the resulting quantised light pulses are affected by neither dispersion nor diffraction and are therefore resilient against external perturbations. The nonlinear interaction of quantised X waves in quadratic and Kerr nonlinear media is also presented and studied in detail.

Topics: Optics, Physics, Quantum Physics

Source: http://arxiv.org/abs/1704.07258

5
5.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Silvia Gentilini; Eugenio DelRe; Claudio Conti

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We investigate the effect of non-paraxiality in the dynamics of dispersive shock waves in the defocusing nonlinear Schroedinger equation. We show that the problem can be described in terms of a relativistic particle moving in a potential. Lowest order corrections enhance the wave-breaking and impose a limit to the highest achievable spectrum in an amount experimentally testable.

Topics: Physics, Optics

Source: http://arxiv.org/abs/1412.8602

5
5.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Marco Ornigotti; Andrea Aiello; Claudio Conti

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We present a theoretical analysis for the \GH and \IF shifts experienced by an X-wave upon reflection from a dielectric interface. We show that the temporal chirp, as well as the bandwidth of the X-wave directly affect the spatial shifts in a way that can be experimentally observed, while the angular shifts do not depend on the spectral features of the X-Wave. A dependence of the spatial shifts on the spatial structure of the X-wave is also discussed.

Topics: Physics, Optics

Source: http://arxiv.org/abs/1411.2376

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6.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Silvia Gentilini; Claudio Conti

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Using light to control the movement of nano-structured objects is a great challenge. This challenge involves fields like optical tweezing, Casimir forces, integrated optics, bio-physics, and many others. Photonic "robots" could have uncountable applications. However, if the complexity of light-activated devices increases, structural disorder unavoidably occurs and, correspondingly, light scattering, diffusion and localization. Are optically-driven mechanical forces affected by...

Topics: Physics, Optics

Source: http://arxiv.org/abs/1410.1919

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5.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Marco Leonetti; Salman Karbasi; Arash Mafi; Claudio Conti

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Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibers in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibers...

Topics: Physics, Optics

Source: http://arxiv.org/abs/1407.8062

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7.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Marco Leonetti; Salman Karbasi; Arash Mafi; Claudio Conti

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We report the experimental observation of the interaction and attraction of many localized modes in a two dimensional (2D) system realized by a disordered optical fiber supporting transverse Anderson localization. We show that a nonlocal optically nonlinear response of thermal origin alters the localization length by an amount determined by the optical power and also induces an action at a distance between the localized modes and their spatial migration. Evidence of a collective and strongly...

Topics: Physics, Optics

Source: http://arxiv.org/abs/1407.7990

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5.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Fabrizio Antenucci; Claudio Conti; Andrea Crisanti; Luca Leuzzi

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We present a unified approach to the theory of multimodal laser cavities including a variable amount of structural disorder. A general mean-field theory is studied for waves in media with variable non-linearity and randomness. Phase diagrams are reported in terms of optical power, degree of disorder and degree of non-linearity, tuning between closed and open cavity scenario's. In the thermodynamic limit of infinitely many modes the theory predicts four distinct regimes: a continuous wave...

Topics: Physics, Statistical Mechanics, Optics, Disordered Systems and Neural Networks, Condensed Matter

Source: http://arxiv.org/abs/1406.7826

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9.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Claudio Conti

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We show that an analog of the physics at the Planck scale can be found in the propagation of tightly focused laser beams. Various equations that occur in generalized quantum mechanics are formally identical to those describing the nonlinear nonlocal propagation of nonparaxial laser beams. The analysis includes a generalized uncertainty principle and shows that the nonlinear focusing of a light beam with dimensions comparable to the wavelength corresponds to the spontaneous excitation of the...

Topics: Physics, High Energy Physics - Theory, Nonlinear Sciences, Quantum Physics, Optics, Pattern...

Source: http://arxiv.org/abs/1406.6677

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7.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Marcello Calvanese Strinati; Claudio Conti

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We consider a microcavity made by a graded-index (GRIN) glass, doped by dye molecules, placed within two planar mirrors and study Bose-Einstein condensation (BEC) of photons. The presence of the mirrors leads to an effective photon mass, and the index grading provides an effective trapping frequency; the photon gas becomes formally equivalent to a two dimensional Bose gas trapped in an isotropic harmonic potential. The inclusion of nonlinear effects provides an effective interaction between...

Topics: Physics, Nonlinear Sciences, Quantum Gases, Optics, Pattern Formation and Solitons, Condensed Matter

Source: http://arxiv.org/abs/1406.6250

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4.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Andrea Armaroli; Claudio Conti; Fabio Biancalana

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Non-deterministic giant waves, denoted as rogue, killer, monster or freak waves, have been reported in many different branches of physics. Their origin is however still unknown: despite the massive numerical and experimental evidence, the ultimate reason for their spontaneous formation has not been identified yet. Here we show that rogue waves in optical fibres actually result from a complex dynamic process very similar to well known mechanisms such as glass transitions and protein folding. We...

Topics: Physics, Nonlinear Sciences, Disordered Systems and Neural Networks, Pattern Formation and...

Source: http://arxiv.org/abs/1406.5966

7
7.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Claudio Conti; Robert Boyd

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A transparent material exhibits ultra-fast optical nonlinearity and is subject to optical pressure if irradiated by a laser beam. However, the effect of nonlinearity on optical pressure is often overlooked, even if a nonlinear optical pressure may be potentially employed in many applications, as optical manipulation, biophysics, cavity optomechanics, quantum optics, optical tractors, and is relevant in fundamental problems as the Abraham-Minkoswky dilemma, or the Casimir effect. Here we show...

Topics: Physics, Quantum Physics, Optics

Source: http://arxiv.org/abs/1403.1948

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4.0

Jun 30, 2018
06/18

Jun 30, 2018
by
Nicola Bulso; Claudio Conti

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We investigate beam diffraction and spatial modulation instability of coherent light beams propagating in the non-paraxial regime in a nonlinear Kerr medium. We study the instability of plane wave solutions in terms of the degree of non-paraxiality, beyond the regime of validity of the nonlinear Schroedinger equation. We also numerically analyze the way non-paraxial terms breaks the integrability and affect the periodical evolution of higher order soliton solutions. We discuss non-locality and...

Topics: Physics, Nonlinear Sciences, Optics, Pattern Formation and Solitons

Source: http://arxiv.org/abs/1402.1161

5
5.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Maria Chiara Braidotti; Silvia Gentilini; Adam Fleming; Michiel C. Samuels; Andrea Di Falco; Claudio Conti

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We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical silica aerogels have nonlinear optical coefficient similar to that of glass $(\simeq 10^{-12} $m$^2/$W), with negligible optical nonlinear absorption. The non\-li\-near coefficient can be increased to values in the range of $10^{-10} $m$^2/$W by embedding an absorbing dye in the aerogel. This value is one order of magnitude higher than that observed in...

Topics: Optics, Condensed Matter, Physics, Other Condensed Matter

Source: http://arxiv.org/abs/1611.00238

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9.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Mohammed F. Saleh; Claudio Conti; Fabio Biancalana

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We unveil the relation between the linear Anderson localisation process and nonlinear modulation instability. Anderson localised modes are formed in certain temporal intervals due to the random background noise. Such localised modes seed the formation of solitary waves that will appear during the modulation instability process at those preferred intervals. Afterwards, optical-event horizon effects between dispersive waves and solitons produce an artificial collective acceleration that favours...

Topics: Optics, Physics

Source: http://arxiv.org/abs/1610.01813

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7.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Leone Di Mauro Villari; Ewan M. Wright; Fabio Biancalana; Claudio Conti

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We have very little experience of the quantum dynamics of the ubiquitous nonlinear waves. Observed phenomena in high energy physics are perturbations to linear waves, and classical nonlinear waves, like solitons, are barely affected by quantum effects. We know that solitons, immutable in classical physics, exhibit collapse and revivals according to quantum mechanics. However this effect is very weak and has never been observed experimentally. By predicting black hole evaporation Hawking first...

Topics: Nonlinear Sciences, Quantum Physics, Quantum Gases, Atomic Physics, Condensed Matter, Physics,...

Source: http://arxiv.org/abs/1608.04905

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7.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Giulia Marcucci; Claudio Conti

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It is well known that a state with complex energy cannot be the eigenstate of a self-adjoint operator, like the Hamiltonian. Resonances, i.e. states with exponentially decaying observables, are not vectors belonging to the conventional Hilbert space. One can describe these resonances in an unusual mathematical formalism, based on the so-called Rigged Hilbert Space (RHS). In the RHS, the states with complex energy are denoted as Gamow Vectors (GV), and they model decay processes. We study GV of...

Topics: Physics, Quantum Physics, Mathematical Physics, Optics, Mathematics

Source: http://arxiv.org/abs/1607.08109

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101

Jun 29, 2018
06/18

Jun 29, 2018
by
Marco Ornigotti; Leone di Mauro Villari; Alexander Szameit; Claudio Conti

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Multi-level quantum protocols may potentially supersede standard quantum optical polarization-encoded protocols in terms of amount of information transmission and security. However, for free space telecomunications, we do not have tools for limiting loss due to diffraction and perturbations, as for example turbulence in air. Here we study propagation invariant quantum X-waves with angular momentum; this representation expresses the electromagnetic field as a quantum gas of weakly interacting...

Topics: Optics, Quantum Physics, Physics

Source: http://arxiv.org/abs/1607.02264

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6.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Maria Chiara Braidotti; Ziad H. Musslimani; Claudio Conti

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The design of optical systems capable of processing and manipulating ultra-short pulses and ultra-focused beams is highly challenging with far reaching fundamental technological applications. One key obstacle routinely encountered while implementing sub-wavelength optical schemes is how to overcome the limitations set by standard Fourier optics. A strategy to overcome these difficulties is to utilize the concept of generalized uncertainty principle (G-UP) that has been originally developed to...

Topics: Exactly Solvable and Integrable Systems, Nonlinear Sciences, Optics, Physics

Source: http://arxiv.org/abs/1604.03405

5
5.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Laura Pilozzi; Claudio Conti

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The use of virtually lossless topologically isolated edge states may lead to a novel class of thresholdless lasers operating without inversion. One needs however to understand if topological states may be coupled to external radiation and act as active cavities. We study a two-level topological insulator and show that self-induced transparency pulses can directly excite edge states. We simulate laser emission by a suitable designed topological cavity, and show that it can emit tunable...

Topics: Mesoscale and Nanoscale Physics, Optics, Condensed Matter, Physics

Source: http://arxiv.org/abs/1602.06782

5
5.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We extend the concept of radially and azimuthally polarized optical beams to the polychromatic domain by introducing cylindrically polarized nondiffracting optical pulses. In particular, we discuss in detail the case of cylindrically polarized X-waves, both in the paraxial and nonparaxial regime. The explicit expressions for the electric and magnetic fields of cylindrically polarized X-waves is also reported.

Topics: Optics, Physics

Source: http://arxiv.org/abs/1602.03317

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9.0

Jun 29, 2018
06/18

Jun 29, 2018
by
Maria Chiara Braidotti; Silvia Gentilini; Claudio Conti

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The description of shock waves beyond the shock point is a challenge in nonlinear physics. Finding solutions to the global dynamics of dispersive shock waves is not always possible due to the lack of integrability. Here we propose a new method based on the eigenstates (Gamow vectors) of a reversed harmonic oscillator in a rigged Hilbert space. These vectors allow analytical formulation for the development of undular bores of shock waves in a nonlinear nonlocal medium. Experiments by a...

Topics: Pattern Formation and Solitons, Nonlinear Sciences, Optics, Physics

Source: http://arxiv.org/abs/1601.05796

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14

Jun 28, 2018
06/18

Jun 28, 2018
by
Silvia Gentilini; Maria Chiara Braidotti; Giulia Marcucci; Eugenio DelRe; Claudio Conti

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Dispersive shock waves dominate wave-breaking phenomena in Hamiltonian systems. In the absence of loss, these highly irregular and disordered waves are potentially reversible. However, no experimental evidence has been given about the possibility of inverting the dynamics of a dispersive shock wave and turn it into a regular wave-front. Nevertheless, the opposite scenario, i.e., a smooth wave generating turbulent dynamics is well studied and observed in experiments. Here we introduce a new...

Topics: Quantum Physics, Optics, Pattern Formation and Solitons, Physics, Nonlinear Sciences

Source: http://arxiv.org/abs/1508.00692

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18

Jun 27, 2018
06/18

Jun 27, 2018
by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We introduce a new class of nondiffracting optical pulses possessing orbital angular momentum. By generalizing the X-waves solution of the Maxwell equation, we discover the coupling between angular momentum and the temporal degrees of freedom of ultra-short pulses. The spatial twist of propagation invariant light pulse turns out to be directly related to the number of optical cycles. Our results may trigger the development on novel multi-level classical and quantum transmission channels free of...

Topics: Optics, Physics

Source: http://arxiv.org/abs/1503.02979

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55

Sep 24, 2013
09/13

Sep 24, 2013
by
Claudio Conti

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The dynamics of several light filaments (spatial optical solitons) propagating in an optically nonlinear and non-local random medium is investigated using the paradigms of the physics of complexity. Cluster formation is interpreted as a dynamic phase transition. A connection with the random matrices approach for explaining the vibrational spectra of an ensemble of solitons is pointed out. General arguments based on a Brownian dynamics model are validated by the numerical simulation of a...

Source: http://arxiv.org/abs/physics/0412051v3

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59

Sep 23, 2013
09/13

Sep 23, 2013
by
Claudio Conti; Giancarlo Ruocco; Stefano Trillo

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We predict that spatial self-trapping of light can occur in soft matter encompassing a wide class of new materials such as colloids, foams, gels, fractal aggregates etc. We develop a general nonlocal theory that allows to relate the properties of the trapped state of Maxwell equations to the measurable static structure factor of the specific material. We give numerical evidence for stable trapping in fractal aggregates and suggest also the possibility of soliton spectroscopy of soft-matter.

Source: http://arxiv.org/abs/physics/0510172v1

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58

Sep 23, 2013
09/13

Sep 23, 2013
by
Neda Ghofraniha; Claudio Conti; Giancarlo Ruocco; Francesco Zamponi

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We investigate the time-dependent nonlinear optical absorption of a clay dispersion (Laponite) in organic dye (Rhodamine B) water solution displaying liquid-arrested state transition. Specifically, we determine the characteristic time $\tau_D$ of the nonlinear susceptibility build-up due as to the Soret effect. By comparing $\tau_D$ with the relaxation time provided by standard dynamic light scattering measurements we report on the decoupling of the two collective diffusion times at the two...

Source: http://arxiv.org/abs/0801.3612v2

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53

Sep 23, 2013
09/13

Sep 23, 2013
by
Silvia Gentilini; Andrea Fratalocchi; Luca Angelani; Giancarlo Ruocco; Claudio Conti

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We investigate the dynamics of a 10 fs light pulse propagating in a random medium by the direct solution of the 3D Maxwell equations. Our approach employs molecular dynamics to generate a distribution of spherical scatterers and a parallel finite-difference time-domain code for the vectorial wave propagation. We calculate the disorder-averaged energy velocity and the decay time of the transmitted pulse Versus the localization length for an increasing refractive index.

Source: http://arxiv.org/abs/0810.1690v1

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86

Sep 23, 2013
09/13

Sep 23, 2013
by
Claudio Conti

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We investigate a special class of cellular automata (CA) evolving in a environment filled by an electromagnetic wave. The rules of the Conway's Game of Life are modified to account for the ability to retrieve life-sustenance from the field energy. Light-induced self-structuring and self-healing abilities and various dynamic phases are displayed by the CA. Photo-driven genetic selection and the nonlinear feedback of the CA on the electromagnetic field are included in the model, and there are...

Source: http://arxiv.org/abs/0810.3179v2

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99

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti

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A quantum theory of 3D X-shaped optical bullets in Kerr media is presented. The existence of progressive undistorted squeezed vacuum is predicted. Applications to quantum non-demolition experiments, entanglement and interferometers for gravitational waves detection are envisaged.

Source: http://arxiv.org/abs/quant-ph/0409130v1

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51

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti

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In the framework of the paraxial and of the slowly varying envelope approximations, with reference to a normally dispersive medium or to vacuum, the electromagnetic field is given as a continuous quantum superposition of non-dispersive and non-diffracting wave-packets (namely X-waves). Entangled states as pairs of elementary excitations traveling at (approximately) the same velocity are found in optical parametric amplification.

Source: http://arxiv.org/abs/quant-ph/0309069v3

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48

Sep 22, 2013
09/13

Sep 22, 2013
by
Andrea Di Falco; Claudio Conti; Gaetano Assanto

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Using a 3D fully-vectorial nonlinear time-domain analysis we numerically investigate the generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead to few-cycle terahertz pulses via optical rectification. Material dispersion as well as linear and nonlinear anisotropy is fully accounted for.

Source: http://arxiv.org/abs/physics/0501065v1

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54

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti

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We study the affinities between the shape of the bright soliton of the one-dimensional nonlinear Schroedinger equation and that of the disorder induced localization in the presence of a Gaussian random potential. With emphasis on the focusing nonlinearity, we consider the bound states of the nonlinear Schroedinger equation with a random potential; for the state exhibiting the highest degree of localization, we derive explicit expressions for the nonlinear eigenvalue and for the localization...

Source: http://arxiv.org/abs/1210.0002v1

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50

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti; Andrea Di Falco; Gaetano Assanto

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We investigate optical parametric oscillations through four-wave mixing in resonant cavities and photonic crystals. The theoretical analysis underlines the relevant features of the phenomenon and the role of the density of states. Using fully vectorial 3D time-domain simulations, including both dispersion and nonlinear polarization, for the first time we address this process in a face centered cubic lattice and in a photonic crystal slab. The results lead the way to the development of novel...

Source: http://arxiv.org/abs/physics/0403013v1

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58

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti; Stefano Trillo

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We predict that an ultra-cold Bose gas in an optical lattice can give rise to a new form of condensation, namely matter X waves. These are non-spreading 3D wave-packets which reflect the symmetry of the Laplacian with a negative effective mass along the lattice direction, and are allowed to exist in the absence of any trapping potential even in the limit of non-interacting atoms. This result has also strong implications for optical propagation in periodic structures

Source: http://arxiv.org/abs/physics/0308051v1

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48

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti; Marco Peccianti; Gaetano Assanto

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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.

Source: http://arxiv.org/abs/physics/0308024v1

48
48

Sep 22, 2013
09/13

Sep 22, 2013
by
Claudio Conti

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We investigate the dynamics of a Bose-Einstein condensate in a progressively bended three dimensional cigar shaped potential. The interplay between geometry and nonlinearity is considered. At high curvature, topological localization occurs and becomes frustrated by the generation of curved dispersive shock-waves when the strength of nonlinearity is increased. The analysis is supported by four-dimensional parallel simulations.

Source: http://arxiv.org/abs/1302.3806v3

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66

Sep 21, 2013
09/13

Sep 21, 2013
by
Claudio Conti; Stefano Trillo

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In the theory of optical gap solitons, slowly-moving finite-amplitude Lorentzian solutions are found to mediate the transition from bright to coexistent dark-antidark solitary wave pairs when the laser frequency is detuned out of the proper edge of a dynamical photonic bandgap. Catastrophe theory is applied to give a geometrical description of this strongly asymmetrical 'morphing' process.

Source: http://arxiv.org/abs/physics/0104042v1

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43

Sep 21, 2013
09/13

Sep 21, 2013
by
Andrea Fratalocchi; Claudio Conti; Giancarlo Ruocco; Stefano Trillo

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We investigate the dynamics of a gas of non-interacting particle-like soliton waves, demonstrating that phase transitions originate from their collective behavior. This is predicted by solving exactly the nonlinear equations and by employing methods of the statistical mechanics of chaos. In particular, we show that a suitable free energy undergoes a metamorphosis as the input excitation is increased, thereby developing a first order phase transition whose measurable manifestation is the...

Source: http://arxiv.org/abs/0808.0882v1

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60

Sep 21, 2013
09/13

Sep 21, 2013
by
Claudio Conti; Eugenio DelRe

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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...

Source: http://arxiv.org/abs/1008.2616v2

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61

Sep 20, 2013
09/13

Sep 20, 2013
by
Claudio Conti; Neda Ghofraniha; Giancarlo Ruocco; Stefano Trillo

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We investigate filamentation of a cw laser beam in soft matter such as colloidal suspensions and fractal gels. The process, driven by electrostriction, is strongly affected by material properties, which are taken into account via the static structure factor, and have impact on the statistics of the light filaments.

Source: http://arxiv.org/abs/cond-mat/0608425v2

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51

Sep 20, 2013
09/13

Sep 20, 2013
by
Claudio Conti; Andrea Fratalocchi

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We report on 3D time-domain parallel simulations of Anderson localization of light in inverted disordered opals displaying a complete photonic band-gap. We investigate dynamic diffusion processes induced by femtosecond laser excitations, calculate the diffusion constant and the decay-time distribution versus the strength of the disorder. We report evidence of the transition from delocalized Bloch oscillations to strongly localized resonances in self-starting laser processes.

Source: http://arxiv.org/abs/0802.3775v1

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Sep 20, 2013
09/13

Sep 20, 2013
by
Bruno Crosignani; Paolo Di Porto; Claudio Conti

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The limits of the Second Law of Thermodynamics, which reigns undisputed in the macroscopic world, are investigated at the mesoscopic level, corresponding to spatial dimensions of a few microns. An extremely simple isolated system, modeled after Callen's adiabatic piston, [1] can, under appropriate conditions, be described as a self-organizing Brownian motor and shown to exhibit a perpetuum mobile behavior.

Source: http://arxiv.org/abs/physics/0410050v2

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Sep 20, 2013
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Sep 20, 2013
by
Jacopo Parravicini; Claudio Conti; Aharon J. Agranat; Eugenio DelRe

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Using the history-dependence of a dipolar glass hosted in a compositionally-disordered lithium-enriched potassium-tantalate-niobate (KTN:Li) crystal, we demonstrate scale-free optical propagation at tunable temperatures. The operating equilibration temperature is determined by previous crystal spiralling in the temperature/cooling-rate phase-space.

Source: http://arxiv.org/abs/1207.0683v1

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Sep 20, 2013
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Sep 20, 2013
by
Marco Leonetti; Claudio Conti; Cefe Lopez

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We show that the degree of localization for the modes of a random laser (RL) is affected by the inter mode interaction that is controlled by shaping the spot of the pump laser. By experimentally investigating the spatial properties of the lasing emission we infer that strongly localized modes are activated in the low interacting regime while in the strongly interacting one extended modes are found lasing. Thus we demonstrate that the degree o localization may be finely tuned at the micrometer...

Source: http://arxiv.org/abs/1207.4181v1

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Sep 20, 2013
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Sep 20, 2013
by
Claudio Conti

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The generation of finite energy packets of X-waves is analysed in normally dispersive cubic media by using an X-wave expansion. The 3D nonlinear Schroedinger model is reduced to a 1D equation with anomalous dispersion. Pulse splitting and beam replenishment as observed in experiments with water and Kerr media are explained in terms of a higher order breathing soliton. The results presented also hold in periodic media and Bose-condensed gases.

Source: http://arxiv.org/abs/physics/0404022v3

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Sep 20, 2013
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Sep 20, 2013
by
Claudio Conti; Luca Angelani; Giancarlo Ruocco

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Using a 3D Finite-Difference Time-Domain parallel code, we report on the linear and nonlinear propagation of light pulses in a disordered assembly of scatterers, whose spatial distribution is generated by a Molecular Dynamics code; refractive index dispersion is also taken into account. We calculate the static and dynamical diffusion constant of light, while considering a pulsed excitation. Our results are in quantitative agreement with reported experiments, also furnishing evidence of a...

Source: http://arxiv.org/abs/cond-mat/0607534v3

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Sep 20, 2013
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Sep 20, 2013
by
Viola Folli; Andrea Puglisi; Luca Leuzzi; Claudio Conti

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Granular materials have been studied for decades, also driven by industrial and technological applications. These very simple systems, composed by agglomerations of mesoscopic particles, are characterized, in specific regimes, by a large number of metastable states and an extreme sensitivity (e.g., in sound transmission) on the arrangement of grains; they are not substantially affected by thermal phenomena, but can be controlled by mechanical solicitations. Laser emission from shaken granular...

Source: http://arxiv.org/abs/1205.5977v1