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Related papers: Perfect Dispersive Medium

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We report a detailed and systematic numerical study of wave propagation through a coherently amplifying random one-dimensional medium. The coherent amplification is modeled by introducing a uniform imaginary part in the site energies of the…

Disordered Systems and Neural Networks · Physics 2009-10-30 Sandeep K. Joshi , A. M. Jayannavar

We give an exact application of a recently developed, operator-based theory of wave propagation in dispersive, time-varying media. Using this theory we find that the usual symmetry of complex conjugation plus changing the sign of the…

We extend the Finite-Difference Time-Domain method to treat dispersive magnetic media by incorporating magneto-optical effects through a frequency-dependent permittivity tensor. For benchmarking our method, we consider the light scattering…

This paper investigates robust semantic communications over multiple-input multiple-output (MIMO) fading channels. Current semantic communications over MIMO channels mainly focus on channel adaptive encoding and decoding, which lacks…

Information Theory · Computer Science 2024-07-09 Yiheng Duan , Tong Wu , Zhiyong Chen , Meixia Tao

A frequency-based omni-temporal dispersion theory is developed to capture the transient interplay between diffusion, advection, and reaction during solute transport through porous media. Unlike classical asymptotic dispersion theories,…

Fluid Dynamics · Physics 2026-05-19 Md Abdul Hamid , Kyle C. Smith

The recent, impressive advances in algorithmic generation of high-fidelity image, audio, and video are largely due to great successes in score-based diffusion models. A key implementing step is score matching, that is, the estimation of the…

Machine Learning · Statistics 2024-09-12 Zehao Dou , Subhodh Kotekal , Zhehao Xu , Harrison H. Zhou

Discrete diffusion has become a leading framework for generative modeling in various applications including language, vision, and biology. Existing convergence theory, however, exhibits fundamental limitations. KL-based analyses diverge…

Machine Learning · Computer Science 2026-05-19 Kelvin Kan , Xingjian Li , Benjamin J. Zhang , Tuhin Sahai , Stanley Osher , Markos A. Katsoulakis

This paper opens up the field of nonuniform-velocity SpaceTime-Modulated (STM) metamaterials, with the canonical example of an STM metamaterial of constant proper acceleration or, equivalently, hyperbolic acceleration. Combining tools of…

Optics · Physics 2022-02-23 Amir Bahrami , Christophe Caloz

Wavefront shaping (WFS) schemes for efficient energy deposition in weakly lossy targets is an ongoing challenge for many classical wave technologies relevant to next-generation telecommunications, long-range wireless power transfer, and…

Disordered Systems and Neural Networks · Physics 2020-11-19 Lei Chen , Tsampikos Kottos , Steven M. Anlage

We unveil a previously overlooked wave propagation regime in magnetized plasmonic (gyrotropic) materials with comparable plasma and cyclotron frequencies, which enables a giant and broadband (nondispersive) nonreciprocal response. We show…

Optics · Physics 2020-10-28 Mohamed Ismail Abdelrahman , Francesco Monticone

This paper addresses optimal decoding strategies in lossy compression where the assumed distribution for compressor design mismatches the actual (true) distribution of the source. This problem has immediate relevance in standardized…

Information Theory · Computer Science 2026-02-04 Saeed R. Khosravirad , Ahmed Alkhateeb , Ingrid van de Voorde

We study the problem of a temporal discontinuity in the permittivity of an unbounded medium with Lorentzian dispersion. More specifically, we tackle the situation in which a monochromatic plane wave forward-travelling in a (generally lossy)…

Optics · Physics 2025-09-24 Diego M. Solís , Raphael Kastner , Nader Engheta

Designing broadband metamaterial perfect absorbers is challenging due to the intrinsically narrow bandwidth of surface plasmon resonances. Here, the paper reports an ultra-broadband metamaterial absorber by using space filling Gosper curve.…

An electromagnetic wave-packet propagating in a linear, homogeneous, and isotropic medium changes shape while its envelope travels with different velocities at different points in spacetime. In general, a wave-packet can be described as a…

Optics · Physics 2020-08-26 Masud Mansuripur

A simple feedback control algorithm is presented for distributed beamforming in a wireless network. A network of wireless sensors that seek to cooperatively transmit a common message signal to a Base Station (BS) is considered. In this…

Information Theory · Computer Science 2007-07-16 R. Mudumbai , J. Hespanha , U. Madhow , G. Barriac

For decades, nonlinear optics has been used to control the frequency and propagation of light in unique ways enabling a wide range of applications such as ultrafast lasing, sub-wavelength imaging, and novel sensing methods. Through this, a…

Optics · Physics 2020-04-02 Ray Secondo , Jacob B. Khurgin , Nathaniel Kinsey

Chromatic dispersion, an inherent wavelength-dependent phenomenon in optical systems, has traditionally been regarded as a detrimental effect to be minimized in imaging and display. Here, we present a paradigm shift by deliberately…

Optics · Physics 2025-12-19 Zi Wang , Dong Zhao , Li Liang , Hengyi Wang , Yuan Liu , Fang-Wen Sun , Kun Huang

Absorption of light is directly associated with dissipative processes in a material. In suitably tailored resonators, a specific level of dissipation can support coherent perfect absorption, the time-reversed analogue of lasing, which…

Optics · Physics 2017-10-26 Denis G Baranov , Alex Krasnok , Andrea Alù

A technique for the design of conformal metasurfaces with two spatially disconnected space wave ports connected by a surface wave is presented. The passive and lossless metasurface absorbs the incident plane wave at port 1, converts it…

Applied Physics · Physics 2023-06-19 Jordan Budhu

This work considers distributed sensing and transmission of sporadic random samples. Lower bounds are derived for the reconstruction error of a single normally or uniformly-distributed finite-dimensional vector imperfectly measured by a…

Information Theory · Computer Science 2015-11-20 Ayşe Ünsal , Raymond Knopp