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Possible squeezed states generated in a three-waveguide nonlinear coupler operating with second harmonic generation is discussed. This study is carried out using two well-known techniques; the phase space method (based on positive…

Ensuring that large language models (LLMs) remain both helpful and harmless poses a significant challenge: fine-tuning on repetitive safety datasets, where unsafe prompts are paired with standard refusal templates, often leads to false…

Machine Learning · Computer Science 2026-03-17 Quan Liu , Han Zhou , Wenquan Wu , Hua Wu , Sen Su

We present an efficient particle filtering algorithm for multiscale systems, that is adapted for simple atmospheric dynamics models which are inherently chaotic. Particle filters represent the posterior conditional distribution of the state…

Data Analysis, Statistics and Probability · Physics 2015-06-04 Nishanth Lingala , N. Sri Namachchivaya , Nicolas Perkowski , Hoong C. Yeong

High-order harmonic generation (HHG) provides a powerful optical tool for probing ultrafast dynamics on the attosecond timescale. While its mechanisms in gases and solids are well-established, understanding nonlinear optical responses in…

In this paper we show how The Free Energy Principle (FEP) can provide an explanation for why real-world networks deviate from scale-free behaviour, and how these characteristic deviations can emerge from constraints on information…

Social and Information Networks · Computer Science 2025-02-19 Peter R Williams , Zhan Chen

Successful synthesis of the nitrogenated holey two-dimensional structures C2N (Nat. Commun. 2015, 6, 1-7) using simply wet-chemical reaction offer a cost-effective way to generate other 2D materials with novel optical and electronic…

Materials Science · Physics 2015-05-12 Ruiqi Zhang , Bin Li , Jinlong Yang

Periodically poled lithium niobate (PPLN) is a widely used nonlinear optical device for second harmonic generation (SHG). Despite its wide adoption in commercial systems, its bandwidth for SHG is fundamentally limited by the quasi-phase…

Optics · Physics 2026-01-30 Yongjoo Kim , Yijia Cai , Zhixin Liu

In this paper, the optimal solution of effective nonlinear coefficient of quasi-phase-matching (QPM) crystals for coupled third harmonic generation (CTHG) was numerically investigated. The effective nonlinear coefficient of CTHG was…

Optics · Physics 2024-03-08 Zihua Zheng , Ziwen Tang , Zhiyi Wei , Jinghua Sun

Recent studies have shown that one-dimensional driven systems can exhibit phase separation even if the dynamics is governed by local rules. The ABC model, which comprises three particle species that diffuse asymmetrically around a ring,…

Statistical Mechanics · Physics 2016-08-31 M. Clincy , B. Derrida , M. R. Evans

This paper develops and analyzes some continuous interior penalty finite element methods (CIP-FEMs) using piecewise linear polynomials for the Helmholtz equation with the first order absorbing boundary condition in two and three dimensions.…

Numerical Analysis · Mathematics 2011-06-22 Haijun Wu

Deep convolutional neural networks often perform poorly when faced with datasets that suffer from quantity imbalances and classification difficulties. Despite advances in the field, existing two-stage approaches still exhibit dataset bias…

Machine Learning · Computer Science 2023-03-16 Liang Xu , Yi Cheng , Fan Zhang , Bingxuan Wu , Pengfei Shao , Peng Liu , Shuwei Shen , Peng Yao , Ronald X. Xu

This paper addresses the problem of robust process and sensor fault reconstruction for nonlinear systems. The proposed method augments the system dynamics with an approximated internal linear model of the combined contribution of known…

Systems and Control · Electrical Eng. & Systems 2023-04-12 Farhad Ghanipoor , Carlos Murguia , Peyman Mohajerin Esfahani , Nathan van de Wouw

This paper derives nonlinear feedback control synthesis for general control affine systems using second-order actions---the second-order needle variations of optimal control---as the basis for choosing each control response to the current…

Robotics · Computer Science 2018-04-26 Giorgos Mamakoukas , Malcolm A. MacIver , Todd D. Murphey

Quasi-phasematched interactions in waveguides with quadratic nonlinearities enable highly efficient nonlinear frequency conversion. In this article, we demonstrate the first generation of devices that combine the dispersion-engineering…

An LCL filter offers superior attenuation for high-frequency harmonics for three-phase grid-following inverters compared to LC and L filters. However, it also introduces an inherent resonance peak, which can lead to power quality issues or…

Systems and Control · Electrical Eng. & Systems 2024-04-09 Naser Souri , Ali Mehrizi-Sani , Kambiz Tehrani

In this report, a novel methodology based on the static coherent states approach is introduced with the capability of calculating various strong-field laser-induced nonlinearities in full dimensional single-electron molecular systems; an…

Quantum Physics · Physics 2019-10-10 Mohammadreza Eidi , Mohsen Vafaee , Hamed Koochaki Kelardeh , Alexandra Landsman

Is the experimental order of convergence lower when using the entropy stable DGSEM-LGL variant? Recently, a debate on the question of the convergence behavior of the entropy stable nodal collocation discontinuous Galerkin spectral element…

Numerical Analysis · Mathematics 2024-12-20 Florian J. Hindenlang , Gregor J. Gassner

By studying the fluorescence and optical properties of a three-level system, we propose a new point of view on the coherent control of these spectra. With the definite phase difference between the fields of the air band and dielectric band…

Materials Science · Physics 2009-11-13 Szu-Cheng Cheng , Jing-Nuo Wu , Tzong-Jer Yang , Wen-Feng Hsieh

Extensive studies have investigated the transition mechanism of boundary layers initiated by a single primary instability. In a real-world scenario, however, multiple primary instabilities of different physical nature would coexist and…

Fluid Dynamics · Physics 2026-03-18 Xiao-Bai Li , Yifeng Chen , Chihyung Wen , Peixu Guo

Local detailed balance (LDB) is a central guiding principle for modeling nonequilibrium stochastic dynamics, yet it only constrains the ratio of forward and backward transition rates and does not fix the steady state. Although the…

Statistical Mechanics · Physics 2026-05-26 Takahiro Kanazawa , Kyogo Kawaguchi , Kyosuke Adachi