Physical world and mathematics

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.

Nonmetal

A nonmetal is a chemical element that mostly lacks metallic attributes, occupying the upper right of the periodic table, with hydrogen as an exception on the left.

Nonparametric statistics

Nonparametric statistics, also known as distribution-free methods, is the branch of statistics that analyzes data without assuming a specific distribution, using rank-based tests, bootstrap resampling, and density estimation.

Nonperturbative quantum gravity

Nonperturbative quantum gravity is the search for a quantum theory of the gravitational field that avoids perturbation theory on a fixed background, pursued mainly through loop quantum gravity, asymptotic safety, and causal set theory.

Nonprobability sampling

Nonprobability sampling is a survey method that selects units by convenience, judgment, or quotas rather than randomly, making it cheaper but harder to measure for error.

Nonradial pulsation

A nonradial pulsation is a stellar oscillation in which the surface deforms in alternating inward and outward regions, described by spherical harmonics with angular degree ℓ greater than 0.

Nonradiating anapole modes

Nonradiating anapole modes are electromagnetic excitations in which electric and toroidal dipole radiation cancel by destructive interference, leaving strong fields confined inside a structure with no net far-field emission.

Nonreciprocal charge transport in superconducting devices

Nonreciprocal charge transport, also called the superconducting diode effect, occurs when the critical supercurrent differs by direction, so supercurrent flows without dissipation one way but with resistance the other.

Nonreciprocal photonic metasurface

A nonreciprocal photonic metasurface is an ultrathin, two-dimensional array of engineered scatterers that transmits or reflects light differently forward and backward, enabling optical isolation and circulation.

Nonreciprocal plasmonic routing

Nonreciprocal plasmonic routing is the direction-dependent control of surface plasmon polaritons so signals propagate one way but not the reverse, requiring broken reciprocity via magneto-optical, nonlinear, or time-modulated mechanisms.

Nonreciprocal wave propagation in active metamaterials

Nonreciprocal wave propagation in active metamaterials is wave transmission through engineered composites that, using external power or control, transmit one way and block the other, as in one-way isolators.

Nonresponse bias

Nonresponse bias is the error in a survey estimate when respondents differ systematically from nonrespondents on the measured quantity; unlike sampling error, it does not shrink as the sample grows.

Nonstandard analysis

Nonstandard analysis is a rigorous formulation of mathematical analysis using actual infinitesimal and infinitely large numbers instead of epsilon-delta limits, introduced by Abraham Robinson at Princeton in 1960.

Nontarget screening

Nontarget screening is an analytical chemistry method that uses high-resolution mass spectrometry to detect and identify chemical compounds in a sample without preselecting which analytes to look for.

Nontargeted analysis

Nontargeted analysis, also called untargeted screening, is an analytical chemistry method that uses high-resolution mass spectrometry to detect unknown chemicals without a predefined target list.

Nonthermal plasma CO2 conversion

Nonthermal plasma CO2 conversion is a chemical process in which energetic electrons split stable CO2 into carbon monoxide and oxygen without heating the bulk gas.

Nonuniform sampling (statistics)

Nonuniform sampling, also called varying probability sampling, is a statistical design that selects units with unequal probabilities, weighted by their inclusion probabilities, to estimate totals more precisely.

Nonylphenol

Nonylphenol (NP) is a man-made mixture of alkylphenols produced mainly for nonylphenol ethoxylate surfactants in detergents; it is persistent, estrogenic, and highly toxic to aquatic life.

Nonylphenol ethoxylate

Nonylphenol ethoxylates are nonionic surfactants made from nonylphenol and ethylene oxide, widely used in detergents, emulsifiers, and textile processing and restricted because they degrade to toxic nonylphenol.

Noon

Noon is the moment when the Sun crosses the local meridian and reaches its highest point in the sky, 12:00 in apparent solar time, also known as apparent noon.

NOON state

The NOON state, also written N00N state, is a maximally path-entangled quantum state of N particles in a two-mode interferometer, named by Kok and coauthors in 2002.

NOR logic

NOR logic is the Boolean operation, written A ↓ B, that outputs true only when all inputs are false; its NOR gate is a universal gate.

Nor'easter

A nor'easter is a powerful coastal storm that moves up the East Coast of North America, bringing strong northeast winds, heavy snow or rain, and coastal flooding.

Sep 21, 2026

Norbert F. Scherer

Norbert F. Scherer is an American physical chemist at the University of Chicago who joined in 1997 and works on ultrafast spectroscopy, single-molecule microscopy, nanoplasmonics, and optical matter.

Norbert Wiener

Norbert Wiener (1894–1964) was an American mathematician at MIT who founded cybernetics, the study of control and communication in animals and machines, and whose wartime work produced the Wiener filter.

Norbinaltorphimine

Norbinaltorphimine (nor-BNI) is a bivalent kappa opioid receptor antagonist, synthesized in 1987 from two naltrexone units, whose exceptionally long-lasting blockade of kappa signaling works through JNK1 activation.

Norbornadiene

Norbornadiene, or bicyclo[2.2.1]hepta-2,5-diene, is a strained bicyclic hydrocarbon first synthesized in 1950, used to make the insecticide Aldrin and studied since the 1970s for storing solar energy as chemical bonds.

Norbornane

Norbornane, also known as norcamphane, is bicyclo[2.2.1]heptane, a saturated bridged bicyclic hydrocarbon with formula C₇H₁₂ and a rigid, canoe-like shape, parent of the family including norbornene and norbornadiene.