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Collective spins in thermal gases are at the core of a multitude of science and technology applications. In most of them, the random thermal motion of the particles is considered detrimental as it is responsible for decoherence and noise.…

Quantum Physics · Physics 2024-02-27 P. Bevington , J. Nicholson , J. D. Zipfel , W. Chalupczak , C. Mishra , V. Guarrera

The concept of nonlinear modes is useful for the dynamical characterization of nonlinear mechanical systems. While efficient and broadly applicable methods are now available for the computation of nonlinear modes, nonlinear modal testing is…

Systems and Control · Electrical Eng. & Systems 2020-11-18 Maren Scheel , Simon Peter , Remco I. Leine , Malte Krack

We present an X-ray based stimulated Raman approach to control the preparation of optically dark electronic states in generic molecular systems. Leveraging on the unique properties of core-level excited states, we demonstrate that optically…

We show that the simultaneous modulation of the propagation constant and of the gain/loss coefficient along the multimode fibers results in unidirectional coupling among the modes, which, depending on the modulation parameters, leads to the…

Optics · Physics 2023-08-09 M. N. Akhter , S. B. Ivars , M. Botey , R. Herrero , K. Staliunas

We theoretically study the excitation spectrum of confined macroscopic optical lattices in the Mott-insulating limit. For large systems, a fast numerical method is proposed to calculate the ground state filling and excitation energies. We…

Quantum Gases · Physics 2009-06-30 Dirk-Sören Lühmann , Kai Bongs , Daniela Pfannkuche

Mode-based model-reduction is used to reduce the degrees of freedom of high dimensional systems, often by describing the system state by a linear combination of spatial modes. Transport dominated phenomena, ubiquitous in technical and…

Numerical Analysis · Mathematics 2020-02-28 Julius Reiss

Nonlinear normal modes (NNMs) are widely used as a tool for developing mathematical models of nonlinear structures and understanding their dynamics. NNMs can be identified experimentally through a phase quadrature condition between the…

Dynamical Systems · Mathematics 2018-07-04 L. Renson , T. L. Hill , D. A. Ehrhardt , D. A. W. Barton , S. A. Neild

Active solids consist of elastically coupled out-of-equilibrium units performing work. They are central to autonomous processes, such as locomotion, self-oscillations and rectification, in biological systems,designer materials and robotics.…

Soft Condensed Matter · Physics 2025-01-17 P. Baconnier , D. Shohat , C. Hernandèz , C. Coulais , V. Démery , G. Düring , O. Dauchot

The coherence of two, coupled two-level systems, representing vibrational modes in a semiclassical model, is calculated in weak and strong fields for various coupling schemes and for different relative phases between initial state…

Chemical Physics · Physics 2009-11-10 S. A. Malinovskaya , P. H. Bucksbaum , P. R. Berman

We present detailed experimental and numerical studies of random lasing in weakly scattering systems. The interference of scattered light, which is weak in the passive systems, is greatly enhanced in the presence of high gain, providing…

Optics · Physics 2009-11-11 X. Wu , W. Fang , A. Yamilov , A. A. Chabanov , A. A. Asatryan , L. C. Botten , H. Cao

Manipulating and controlling the optical energy flow inside random media is a research frontier of photonics and the basis of novel laser designs. In particular, light amplification in randomly dispersed active inclusions under external…

Optics · Physics 2015-12-15 Andrea Marini , F. Javier García de Abajo

We experimentally investigate the parametric down-conversion process in a nonlinear bulk crystal, driven by two non-collinear pump modes. The experiment shows the emergence of bright hot-spots in modes shared by the two pumps, in analogy…

Quantum Physics · Physics 2020-12-30 Ottavia Jedrkiewicz , Erica Invernizzi , Enrico Brambilla , Alessandra Gatti

We present a theoretical framework that unifies pump absorption, gain saturation, thermo-optic distortion, and cavity diffraction into a self-consistent model of multi-pass pumped solid-state lasers. By deriving a theoretical formulation of…

A strongly confined light field necessarily exhibits a local polarization that varies on a subwavelength scale. We demonstrate that a single optical mode of such kind can be used to selectively and simultaneously manipulate atomic ensembles…

Quantum Physics · Physics 2014-08-07 R. Mitsch , C. Sayrin , B. Albrecht , P. Schneeweiss , A. Rauschenbeutel

Understanding coherent optical responses of topological surface states (TSSs) requires disentangling excitation pathways from the electronic band structure. Here, using angle-resolved two-photon photoemission spectroscopy, we identify two…

Particle-particle interaction provides a new degree of freedom to induce novel topological phenomena. Here, we propose to use spatiotemporal modulation of interaction to realize topological pumping without single-particle counterpart.…

Mesoscale and Nanoscale Physics · Physics 2024-10-28 Boning Huang , Yongguan Ke , Wenjie Liu , Chaohong Lee

A study on the effects of optical gain nonuniformly distributed in one-dimensional random systems is presented. It is demonstrated numerically that even without gain saturation and mode competition, the spatial nonuniformity of gain can…

Optics · Physics 2010-08-25 Jonathan Andreasen , Christian Vanneste , Li Ge , Hui Cao

Statistical properties of a laser based on a one-dimensional disordered superlattice open at one side are studied numerically. The passive normal modes of the system are determined using the Feshbach projection technique. It is found that…

Optics · Physics 2009-02-02 Oleg Zaitsev , Lev Deych , Vladimir Shuvayev

In this manuscript we report on adiabatic pumping in quasiperiodic stiffness modulated beams. We show that distinct topological states populating nontrivial gaps can nucleate avoided crossings characterized by edge-to-edge transitions. Such…

Applied Physics · Physics 2020-07-15 Emanuele Riva , Vito Casieri , Ferruccio Resta , Francesco Braghin

Metasurfaces have attracted extensive interests due to their ability to locally manipulate optical parameters of light and easy integration to complex optical systems. Particularly, metasurfaces can provide a novel platform for splitting…