All articles starting with N

Nonlinear gameplay

Nonlinear gameplay: video game design where players pursue objectives through multiple sequences, routes, or choices rather than one fixed path. Also called branching or open-ended play; central to open-world, immersive sim, and branching-narrative design, trading narrative control for player agency and replayability.

Nonlinear guidance law

The nonlinear guidance law (NLGL) is a geometric path-following algorithm introduced by Park, Deyst, and How in 2007, computing lateral acceleration from a look-ahead point on the desired path.

Nonlinear Hall effect

The nonlinear Hall effect is a transverse voltage arising without a magnetic field in materials whose inversion symmetry is broken, predicted in 2015 and observed in bilayer WTe2 in 2018.

Nonlinear Hall effect in Weyl semimetals

The nonlinear Hall effect in Weyl semimetals is a transverse voltage at zero magnetic field that scales quadratically with current, driven by the Berry curvature dipole.

Nonlinear interference noise

Nonlinear interference noise (NLIN) is noise-like signal distortion in wavelength-division multiplexed optical fiber systems caused by the fiber's Kerr nonlinearity, commonly modeled with the Gaussian noise model.

Nonlinear metamaterials

Nonlinear metamaterials are artificially structured composites whose response to a wave depends on its intensity, spanning optical, acoustic, and mechanical designs for frequency conversion, nonreciprocity, and vibration control.

Nonlinear metasurface harmonic generation

Nonlinear metasurface harmonic generation is the conversion of light to harmonics of its frequency by metasurfaces, whose nanoresonators are far smaller than the nonlinear coherence length, relaxing phase matching and enabling wavefront-shaped harmonic light.

Nonlinear metasurfaces

Nonlinear metasurfaces are ultrathin, planar arrays of engineered nanostructures that convert light to new frequencies via harmonic generation while controlling the wavefront, without the phase-matching limits of bulk crystals.

Nonlinear mixed-effects model

A nonlinear mixed-effects model (NLME model) is a statistical model for repeated-measures data in which some parameters vary between individuals, and the standard tool of pharmacometrics.

Nonlinear model predictive control

Nonlinear model predictive control is a control strategy that solves a constrained optimization online at each sampling instant using a nonlinear plant model over a prediction horizon.

Nonlinear model reduction

Nonlinear model reduction is a family of computational methods that builds low-dimensional approximate models of high-dimensional nonlinear dynamical systems, typically by projecting the full model onto a low-dimensional subspace, enabling fast simulation, optimization, and real-time control.

Nonlinear narrative

Nonlinear narrative, also called non-chronological or fractured storytelling, presents events out of chronological order via flashbacks, parallel timelines, or reverse order, separating story time from discourse order across literature, film, and games.

Nonlinear optical loop mirror

The nonlinear optical loop mirror (NOLM) is an all-optical switching device made of a fiber loop and coupler, where a Kerr-effect asymmetry makes transmission depend on light power.

Nonlinear optical microscopy

Nonlinear optical microscopy is a family of imaging techniques that use nonlinear light–matter interactions, such as multiphoton absorption and harmonic generation, to image live tissue.

Nonlinear optics

Nonlinear optics is the branch of optics studying effects that appear when a material's response to light is no longer proportional to the light's electric field.

Nonlinear phase noise

Nonlinear phase noise, or the Gordon–Mollenauer effect, is phase noise in optical fiber communication that arises when amplifier noise interacts with the Kerr nonlinearity, converting amplitude fluctuations into phase fluctuations.

Nonlinear phononics

Nonlinear phononics is a technique for controlling the structure and functional properties of solids, in which intense mid-infrared or terahertz light pulses drive phonons to large amplitudes, inducing targeted crystal deformations.

Nonlinear programming

Nonlinear programming, also known as nonlinear optimization, is the branch of mathematical optimization dealing with problems whose objective function, constraints, or both are nonlinear, generalizing linear programming.

Nonlinear regression

Nonlinear regression is a form of regression analysis in which the expected response is modeled by a function nonlinear in the unknown parameters, estimated by iterative least squares algorithms such as Levenberg-Marquardt.

Nonlinear Schrödinger equation

The nonlinear Schrödinger equation (NLS) is a partial differential equation combining dispersion and nonlinear self-interaction, with focusing and defocusing regimes, and applications in optics, water waves, and Bose–Einstein condensation.

Nonlinear sigma model

The nonlinear sigma model is a field theory whose field maps spacetime into a curved target manifold, governed by the target metric; it is named for the σ particle of Gell-Mann and Lévy's 1960 model.

Nonlinear static analysis

Nonlinear static analysis, widely known as pushover analysis, is a structural analysis method that applies an incrementally increasing lateral load to a structural model until a target displacement is reached.

Nonlinear system

A nonlinear system is a system whose equations describe behavior where output is not proportional to input; when the equations evolve in time it is called a dynamical system.

Nonlinear system identification

Nonlinear system identification is the construction of mathematical models of nonlinear dynamical systems from measured input and output data, using structures such as NARMAX, block-oriented, and neural state-space models.

Nonlinear time history analysis

Nonlinear time history analysis (NTHA) is a structural engineering method that integrates earthquake ground motion records through a nonlinear model to compute displacements, forces, and damage.

Nonlinearity (journal)

Nonlinearity is a peer-reviewed scientific journal covering nonlinear mathematics and nonlinear science, founded in 1988 by the Institute of Physics and the London Mathematical Society and published by IOP Publishing.

Nonlocal metasurface

A nonlocal metasurface is an optical or mechanical surface built from subwavelength elements whose response depends on the incident wave vector, enabling resonant functions like spatial differentiation and edge detection.

Nonlocal response in plasmonic resonators

Nonlocal response in plasmonic resonators is the wave-vector dependence of a metal's optical response, which emerges when plasmonic structure dimensions approach 1 to 10 nm and the local-response approximation breaks down.

Nonlocal rheology of soft glassy flows

Nonlocal rheology of soft glassy flows describes how flow in dense amorphous materials like foams and pastes depends on surrounding regions over a finite cooperativity length.