We report on the generation, subsequent oscillation and interaction of a pair matter-wave dark solitons. These are created by releasing Bose-Einstein condensate from double well potential into harmonic trap in crossover regime between one dimension three dimensions. Multiple oscillations collisions solitons observed, quantitative agreement with simulations Gross-Pitaevskii equation. An effective particle picture is developed confirms that deviation observed frequencies asymptotic prediction...

Abstract Perfect absorption is an interdisciplinary topic with a large number of applications, the challenge which consists broadening its inherently narrow frequency-band performance. We experimentally and analytically report perfect broadband for audible sound, by mechanism critical coupling, sub-wavelength multi-resonant scatterer (SMRS) made plate-resonator/closed waveguide structure. In order to introduce role key parameters, we first present case single resonant (SRS) Helmholtz...

We report the experimental observation of modulational instability and discrete breathers in a one-dimensional diatomic granular crystal composed compressed elastic beads that interact via Hertzian contact. first characterize their effective linear spectrum both theoretically experimentally. then illustrate numerically lower edge optical band. This leads to dynamical formation long-lived breather structures, whose families solutions we compute throughout spectral gap. Finally, experimentally...

The reflection of sound frequency below 1 kHz, by a rigid-backed structure that contains sub-wavelength resonators is studied in this work. In particular, only single mode reflected waves are considered, an approximation which accurate low regime. A method analysis absorption uses the coefficient complex plane proposed. absence losses, supports pairs poles and zeros conjugate have imaginary parts linked to energy leakage radiation. When losses introduced balanced leakage, critical coupling...

An experimentally realizable scheme of periodic sign-changing modulation the scattering length is proposed for Bose-Einstein condensates similar to dispersion-management schemes in fiber optics. Because controlling via Feshbach resonance, named Feshbach-resonance management. The modulational-instability analysis quasiuniform condensate driven by this leads an analog Kronig-Penney model. ensuing stable localized structures are found. These include breathers, which oscillate between...

We introduce the concept of ring dark solitons in Bose-Einstein condensates. show that relatively shallow rings are not subject to snake instability, but a deeper splits into robust ringlike cluster vortex pairs, which performs oscillations radial and azimuthal directions, following dynamics original soliton.

We experimentally report perfect acoustic absorption through the interplay of inherent losses and transparent modes with high Q factor. These are generated in a two-port, one-dimensional waveguide, which is side-loaded by isolated resonators moderate In symmetric structures, we show that presence small losses, these lead to coherent associated one-sided slightly larger than 0.5. asymmetric near possible (96%) deep sub-wavelength sample (λ/28, where λ wavelength sound wave air). The control...

We consider the stability and dynamics of multiple dark solitons in cigar-shaped Bose-Einstein condensates. Our study is motivated by fact that matter-wave may naturally form such settings as per our recent work [Phys. Rev. Lett. 101, 130401 (2008)]. First, we soliton interactions show well-separated (i.e., ones undergo a collision with relatively low velocities) can be analyzed means particle-like equations motion. The latter take into regard repulsion between (via an effective repulsive...

We investigate sound propagation in lossy, locally resonant periodic structures by studying an air-filled tube periodically loaded with Helmholtz resonators and taking into account the intrinsic viscothermal losses. In particular, tuning resonator Bragg gap this prototypical structure, we study limits various characteristics of slow propagation. While lossless case overlapping gaps results slow-sound-induced transparency a narrow frequency band surrounded strong broadband gap, inclusion...

Effective non-Hermitian Hamiltonians are obtained to describe coherent perfect absorbing and lasing boundary conditions. PT -symmetry of the enables design configurations which perfectly absorb at multiple frequencies. Broadened flat absorption is predicted exceptional point breaking while, for a particular case, enhanced with use gain. The aforementioned phenomena illustrated acoustic scattering through Helmholtz resonators revealing how tailoring non-Hermiticity metamaterials leads novel...

In the present work, we experimentally implement, numerically compute with, and theoretically analyze a configuration in form of single column woodpile periodic structure. Our main finding is that Hertzian, locally resonant, lattice offers test bed for formation genuinely traveling waves composed strongly localized solitary wave on top small amplitude oscillatory tail. This type wave, called nanopteron, not only motivated numerically, but also visualized by means laser Doppler vibrometer....

Abstract Demonstration of topological boundary modes in elastic systems has attracted a great deal attention over the past few years due to its unique protection characteristic. Recently, second-order insulators have been proposed manipulating topologically protected localized states emerging only at corners. Here, we numerically and experimentally study corner two-dimensional phononic crystal, namely continuous plate with embedded bolts hexagonal pattern. We create interfacial corners by...

We examine the role of strong nonlinearity on topologically-robust edge state in a one-dimensional system. consider chain inspired from Su-Schrieffer-Heeger model, but with finite-frequency and dynamics governed by second-order differential equations. introduce cubic onsite-nonlinearity study this nonlinear effect state's frequency linear stability. Nonlinear continuation reveals that loses its typical shape enforced chiral symmetry becomes generally unstable due to various types...

The modulational instability of the nonlinear Schr\"odinger (NLS) equation is examined in case with a quadratic external potential. This study motivated by recent experimental results context matter waves Bose-Einstein condensates (BECs). theoretical analysis invokes lens-type transformation that converts Gross-Pitaevskii into modified NLS without explicit spatial dependence. suggests particular interest specific time-varying potential $[\ensuremath{\sim}{(t+t}^{*}{)}^{\ensuremath{-}2}].$ We...

We investigate the dynamics of matter-wave solitons in presence a spatially varying atomic scattering length and nonlinearity. The bright dark solitary waves is studied using corresponding Gross-Pitaevskii equation. numerical results are shown to be very good agreement with predictions effective equations motion derived by adiabatic perturbation theory. dependent nonlinearity leads gravitational potential that allows influence both fundamental as well higher order solitons.

We study localized modes in uniform one-dimensional chains of tightly packed and uniaxially compressed elastic beads the presence one or two light-mass impurities. For composed same type, intrinsic nonlinearity, which is caused by Hertzian interaction beads, appears not to support localized, breathing modes. Consequently, inclusion impurities crucial for their appearance. By analyzing problem's linear limit, we identify system's eigenfrequencies defect Using continuation techniques, find...

We study wave propagation in a chain of spherical particles containing local resonator. The resonant are made an aluminum outer shell and steel inner mass connected by polymeric plastic structure acting as spring. characterize the dynamic response individual transmitted linear spectra contact. A wide band gap is observed both theoretical experimental results. show ability to tune acoustic transmission varying contact interaction between particles. Higher driving amplitude leads generation...

We propose a fast and robust quantum state transfer protocol employing Su-Schrieffer-Heeger chain, where the interchain couplings vary in time. Based on simple considerations around terms involved definition of adiabatic invariant, we construct an exponential time-driving function that successfully takes advantage resonant effects to speed up process. Using optimal control theory, confirm proposed is close optimal. To unravel crucial aspects our construction, proceed comparison with two...

Topological physics strongly relies on prototypical lattice model with particular symmetries. We report here a theoretical and experimental work acoustic waveguides that is directly mapped to the one-dimensional Su-Schrieffer-Heeger chiral model. Starting from continuous two dimensional wave equation we use combination of monomadal approximation condition equal length tube segments arrive at wanted discrete equations. It shown open or closed boundary conditions topological leads...

A remarkable feature of the trimer Su-Schrieffer-Heeger (SSH3) model is that it supports localized edge states. However, in contrast to dimer version model, a change total number states SSH3 without mirror-symmetry not necessarily associated with phase transition, i.e., closing band gap. As such, topological invariant predicted by 10-fold way classification does always coincide present. Moreover, although Zak's remains quantized for case mirror-symmetric chain, known fails take integer...

Abstract Topological mechanical metamaterials have been widely explored for their boundary states, which can be robustly isolated or transported in a controlled manner. However, such systems often require pre-configured design complex active actuation wave manipulation. Here, we present the possibility of in-situ transfer topological modes by leveraging reconfigurability intrinsic twisted origami lattices. In particular, employ dimer Kresling system consisting unit cells with opposite...

Motivated by recent experimental studies of matter waves and optical beams in double-well potentials, we study the corresponding solutions nonlinear Schr\"odinger equation. Using a Galerkin-type approach, obtain detailed handle on solution branches problem, starting from linear ones, predict relevant bifurcations for both attractive repulsive nonlinearities. The dynamics ensuing unstable is also examined. results illustrate differences that arise between steady states emerging symmetric...

We present a systematic study of the existence and stability discrete breathers that are spatially localized in bulk one-dimensional chain compressed elastic beads interact via Hertzian contact. The is diatomic, consisting periodic arrangement heavy light spherical particles. examine two families gap breathers: (1) an unstable breather centered on particle characterized by symmetric spatial energy profile (2) potentially stable asymmetric profile. investigate their existence, structure,...

We investigate the tunable vibration filtering properties of statically compressed one-dimensional diatomic granular crystals composed arrays stainless steel spheres and cylinders interacting via Hertzian contact. The consist periodically repeated three-particle unit cells (sphere-cylinder-sphere) in which length cylinder is varied systematically. response these crystals, given small amplitude dynamic displacements relative to those due static compression, characterize their linear frequency...