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Acoustic phased arrays are capable of steering and focusing a beam of sound via selective coordination of the spatial distribution of phase angles between multiple sound emitters. Constrained by the principle of reciprocity, conventional…

Applied Physics · Physics 2021-11-16 R. Adlakha , M. Moghaddaszadeh , M. A. Attarzadeh , A. Aref , M. Nouh

Many real-world time series exhibit strong periodic structures arising from physical laws, human routines, or seasonal cycles. However, modern deep forecasting models often fail to capture these recurring patterns due to spectral bias and a…

Machine Learning · Computer Science 2025-08-05 Menglin Kong , Vincent Zhihao Zheng , Lijun Sun

We introduce the Latent Fourier Transform (LatentFT), a framework that provides novel frequency-domain controls for generative music models. LatentFT combines a diffusion autoencoder with a latent-space Fourier transform to separate musical…

Sound · Computer Science 2026-04-21 Mason Wang , Cheng-Zhi Anna Huang

This work introduces a new class of PT-symmetry grating assisted devices for switching or modulation applications. Their operation is based on a four-wave interaction, thus marking a step in the further development of PT-symmetry devices…

Optics · Physics 2015-06-18 Anatole Lupu , Henri Benisty , Aloyse Degiron

Scene Graph Generation (SGG) remains a challenging task due to its compositional property. Previous approaches improve prediction efficiency through end-to-end learning. However, these methods exhibit limited performance as they assume…

Computer Vision and Pattern Recognition · Computer Science 2025-05-15 Peng Hao , Weilong Wang , Xiaobing Wang , Yingying Jiang , Hanchao Jia , Shaowei Cui , Junhang Wei , Xiaoshuai Hao

Graph signal processing extends spectral analysis to data supported on irregular domains. Existing fractional transforms for two-dimensional graph signals, including the two-dimensional graph fractional Fourier transform (GFRFT), typically…

Signal Processing · Electrical Eng. & Systems 2026-03-03 Mingzhi Wang , Manjun Cui , Feiyue Zhao , Yangfan He , Zhichao Zhang

In spherical tokamaks, the electron plasma frequency is greater than the electron cyclotron frequency. Electromagnetic waves in the electron cyclotron range of frequencies are unsuitable for directly heating such plasmas due to their…

Plasma Physics · Physics 2018-11-14 N. A. Lopez , A. K. Ram

Time modulation can cause gain and loss in photonic media, leading to complex modal behaviors and enhanced wave controllability in the non-Hermitian regime. Conversely, we reveal that Hermiticity and parity-time $\mathcal{PT}$-symmetry…

Optics · Physics 2025-07-08 Rui-Chuan Zhang , Shu Yang , Yixin Sha , Zetao Xie , Yi Yang

In this paper, the forward and backward propagating modes in an optical waveguide structure namely the fiber Bragg filter also considered as a one dimensional photonic crystal, are analytically computed as a function of grating length for…

General Physics · Physics 2014-05-29 Sourangsu Banerji

The nonstationary nature of signals and nonlinear systems require the time-frequency representation. In time-domain signal, frequency information is derived from the phase of the Gabor's analytic signal which is practically obtained by the…

Information Theory · Computer Science 2016-04-19 Pushpendra Singh

Dynamic modulation of material properties in space and time enables powerful control over wave propagation, yet existing theories largely rely on idealized, nondispersive models. In realistic media, frequency dispersion can strongly reshape…

Optics · Physics 2026-04-02 Klaas De Kinder , Christophe Caloz

Quantum fluctuations of optical fiber Bragg grating solitons are investigated numerically by the back-propagation method. It is found for the first time that the bandgap effects of the grating act as a nonlinear filter and cause the soliton…

Quantum Physics · Physics 2007-05-23 Ray-Kuang Lee , Yinchieh Lai

The Smith Purcell effect, observed when an electron beam passes in the vicinity of a periodic structure, is a promising platform for the generation of electromagnetic radiation in previously-unreachable spectral ranges. However, most of the…

In this paper, we study the dynamic formation of transients when plane waves impinge on a dispersive slab that abruptly changes its electrical properties in time. The time-varying slab alternates between air and metal-like states, whose…

Gravitational-wave memory is characterized by a signal component that persists after a transient signal has decayed. Treating such signals in the frequency domain is non-trivial, since discrete Fourier transforms assume periodic signals on…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Jorge Valencia , Rodrigo Tenorio , Maria Rosselló-Sastre , Sascha Husa

We have developed an integrated dual-band photonic filter (PF) utilizing equivalent chirped four-phase-shifted sidewall-sampled Bragg gratings (4PS-SBG) on a silicon-on-insulator (SOI) platform. Using the reconstruction equivalent-chirp…

The combination of grating-based frequency-selective optical feedback mechanisms, such as distributed feedback (DFB) or distributed Bragg reflector (DBR) structures, with quantum dot (QD) gain materials is a main approach towards…

The central theme of this article is the analysis of the usefulness of introducing four-wave mixing or modulation of Kerr nonlinearity in a nonuniform grating structure with gain and loss. To do so, we propose an inhomogeneous system in…

Optics · Physics 2022-02-16 S. Sudhakar , S. Vignesh Raja , A. Govindarajan , K. Batri , M. Lakshmanan

We present Q-Transform Amplitude Modulation (QTAM), a novel, fully invertible implementation of the Constant-Q Transform algorithm, designed to enable robust signal denoising and the disentanglement of overlapping transient events in…

General Relativity and Quantum Cosmology · Physics 2026-04-01 Lorenzo Asprea , Francesco Sarandrea , Alessio Romano , Jacob Lange , Federica Legger , Sara Vallero

In this work, we investigate the properties of four-wave mixing Bragg scattering in a configuration that employs orthogonally polarized pumps in a birefringent waveguide. This configuration enables a large signal conversion bandwidth, and…