Noether symmetries and the quantization of a Lienard-type nonlinear oscillator

The classical quantization of a Lienard-type nonlinear oscillator is achieved by a quantization scheme (M.C. Nucci. Theor. Math. Phys., 168:997--1004, 2011) that preserves the Noether point symmetries of the underlying Lagrangian in order to construct the Schr\"odinger equation. This method straightforwardly yields the correct Schr\"odinger equation in the momentum space (V. Chithiika Ruby, M. Senthilvelan, and M. Lakshmanan. J. Phys. A: Math. Gen., 45:382002, 2012), and sheds light into the apparently remarkable connection with the linear harmonic oscillator.Comment: 18 page

Quantization of quadratic Li\'enard-type equations by preserving Noether symmetries

The classical quantization of a family of a quadratic Li\'{e}nard-type equation (Li\'{e}nard II equation) is achieved by a quantization scheme (M.~C. Nucci. {\em Theor. Math. Phys.}, 168:994--1001, 2011) that preserves the Noether point symmetries of the underlying Lagrangian in order to construct the Schr\"odinger equation. This method straightforwardly yields the Schr\"odinger equation as given in (A.~Ghose~Choudhury and Partha Guha. {\em J. Phys. A: Math. Theor.}, 46:165202, 2013).Comment: 13 pages. arXiv admin note: text overlap with arXiv:1307.3803 in the Introduction since the authors' method of quantization is described agai

Brillouin light scattering studies of planar metallic magnonic crystals

The application of Brillouin light scattering to the study of the spin-wave spectrum of one- and two-dimensional planar magnonic crystals consisting of arrays of interacting stripes, dots and antidots is reviewed. It is shown that the discrete set of allowed frequencies of an isolated nanoelement becomes a finite-width frequency band for an array of identical interacting elements. It is possible to tune the permitted and forbidden frequency bands, modifying the geometrical or the material magnetic parameters, as well as the external magnetic field. From a technological point of view, the accurate fabrication of planar magnonic crystals and a proper understanding of their magnetic excitation spectrum in the GHz range is oriented to the design of filters and waveguides for microwave communication systems

Superintegrable systems in non-Euclidean plane: hidden symmetries leading to linearity

Nineteen classical superintegrable systems in two-dimensional non-Euclidean spaces are shown to possess hidden symmetries leading to their linearization. They are the two Perlick systems [A. Ballesteros, A. Enciso, F.J. Herranz and O. Ragnisco, Class. Quantum Grav. 25, 165005 (2008)], the Taub-NUT system [A. Ballesteros, A. Enciso, F.J. Herranz, O. Ragnisco, and D. Riglioni, SIGMA 7, 048 (2011)], and all the seventeen superintegrable systems for the four types of Darboux spaces as determined in [E.G. Kalnins, J.M. Kress, W. Miller, P. Winternitz, J. Math. Phys. 44, 5811--5848 (2003)]

Collective spin waves in arrays of Permalloy nanowires with single-side periodically modulated width

We have experimentally and numerically investigated the dispersion of collective spin waves prop-agating through arrays of longitudinally magnetized nanowires with periodically modulated width. Two nanowire arrays with single-side modulation and different periodicity of modulation were studied and compared to the nanowires with homogeneous width. The spin-wave dispersion, meas-ured up to the third Brillouin zone of the reciprocal space, revealed the presence of two dispersive modes for the width-modulated NWs, whose amplitude of magnonic band depends on the modula-tion periodicity, and a set of nondispersive modes at higher frequency. These findings are different from those observed in homogeneous width NWs where only the lowest mode exhibits sizeable dis-persion. The measured spin-wave dispersion has been satisfactorily reproduced by means of dynam-ical matrix method. Results presented in this work are important in view of the possible realization of frequency tunable magnonic device

EH-DPD: a dissipative particle dynamics approach to electrohydrodynamics

Abstract: Electrohydrodynamics is crucial in many nanofluidic and biotechnological applications. In such small scales, the complexity due to the coupling of fluid dynamics with the dynamics of ions is increased by the relevance of thermal fluctuations. Here, we present a mesoscale method based on the Dissipative Particle Dynamics (DPD) model of the fluid. Two scalar quantities, corresponding to the number of positive and negative ions carried by each DPD particle, are added to the standard DPD formulation. We introduced a general framework that, given the definition of the free-energy of the DPD particle, allows to derive a fluctuation-dissipation relation and the expression for ionic fluxes between the DPD particles. This provides a link between the dynamics of the system and its equilibrium properties. The model is then validated simulating a planar electroosmotic flow for the cases of overlapping and non overlapping electric double layers. It is shown that using a Van der Waals equation of state the effect of ionic finite size can be accounted, leading to significant effects on the concentration and velocity profiles with respect to the ideal solution case. Graphic abstract: [Figure not available: see fulltext.]

Discrete Integrable Systems and Random Lax Matrices

We study properties of Hamiltonian integrable systems with random initial data by considering their Lax representation. Specifically, we investigate the spectral behaviour of the corresponding Lax matrices when the number N of degrees of freedom of the system goes to infinity and the initial data is sampled according to a properly chosen Gibbs measure. We give an exact description of the limit density of states for the exponential Toda lattice and the Volterra lattice in terms of the Laguerre and antisymmetric Gaussian beta-ensemble in the high temperature regime. For generalizations of the Volterra lattice to short range interactions, called INB additive and multiplicative lattices, the focusing Ablowitz-Ladik lattice and the focusing Schur flow, we derive numerically the density of states. For all these systems, we obtain explicitly the density of states in the ground states

The efficacy and safety of duloxetine in a multidrug regimen for chronic prostatitis/chronic pelvic pain syndrome.

OBJECTIVE To evaluate the efficacy and safety of duloxetine hydrochloride in the treatment of patients affected by chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). METHODS Thirty-eight CP/CPPS patients completed the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and International Index of Erectile Function-Erectile Function-5 (IIEF-5) questionnaires, uroflowmetry, and evaluation of psychologic status using Hamilton Anxiety Scale (HAM-A) and Hamilton Depression Scale (HAM-D). Patients were randomly assigned to 2 treatments groups. Treatment in group 1 consisted of a simultaneous oral administration of tamsulosin (0.4 mg/d, 60 mg/d), saw palmetto (320 mg/d), and duloxetine (60 mg/d). Treatment in group 2 consisted of tamsulosin (0.4 mg/d) and saw palmetto (320 mg/d). NIH-CPSI and IIEF-5 questionnaires, uroflowmetry, and evaluation of the psychological status were repeated at 16 weeks of follow-up. RESULTS At 16 weeks, a significant improvement in NIH-CPSI pain subscore, NIH-CPSI quality of life subscore, and NIH-CPSI total score were observed in group 1 patients compared with those in group 2 (P <.01, respectively), together with a significant improvement in HAM-A and HAM-D scores (P <.01, respectively). Patients in group 2 showed a significant improvement in NIH-CPSI total score, in the urinary symptoms subscore, and in the HAM-A total score. No significant differences were observed in IIEF-5 scores in the 2 groups. Maximum flow rate significantly increased in both groups. In group 1, 20% of patients stopped the study due to adverse effects. CONCLUSION The use of duloxetine in a multimodal treatment with an alpha-blocker medication and a saw palmetto extract allowed better results in controlling clinical symptoms, psychologic status and quality of life patients affected by CP/CPPS

Polarization proximity effect in isolator crystal pairs

We experimentally studied the polarization dynamics (orientation and ellipticity) of near infrared light transmitted through magnetooptic Yttrium Iron Garnet crystal pairs using a modified balanced detection scheme. When the pair separation is in the sub-millimeter range, we observed a proximity effect in which the saturation field is reduced by up to 20%. 1D magnetostatic calculations suggest that the proximity effect originates from magnetostatic interactions between the dipole moments of the isolator crystals. This substantial reduction of the saturation field is potentially useful for the realization of low-power integrated magneto-optical devices.Comment: submitted to Optics Letter