Physical world and mathematics

Interfacial water structure in electrocatalysis

Interfacial water structure in electrocatalysis is the molecular orientation and hydrogen bonding of water adjacent to an electrode, which governs proton transfer and reaction rates, including hydrogen evolution and carbon dioxide reduction.

Interference filter

An interference filter, also called a dichroic or thin-film filter, is an optical filter that transmits chosen wavelengths via interference between reflections from dozens of alternating dielectric layers, used in fluorescence microscopy and LIDAR.

Interference microscopy

Interference microscopy is an optical technique that measures the optical path difference between a specimen beam and a reference beam, converting it into surface height, optical thickness, or refractive-index maps.

Interference of light

Interference of light is the redistribution of optical energy when two or more light waves superpose, producing bright and dark fringes where waves arrive in or out of step.

Interferometric imaging

Interferometric imaging reconstructs an image of a distant or large object by coherently combining signals from separated antennas or apertures, a technique central to radio astronomy and used in InSAR.

Interferometric microscopy

Interferometric microscopy is a noncontact optical technique that measures surface topography and phase variations by interference, delivering full-field 3D maps with sub-nanometer resolution for industrial metrology and biological imaging.

Interferometric particle imaging

Interferometric particle imaging (IPI), also called interferometric laser imaging for droplet sizing (ILIDS), is an optical diagnostic measuring droplet size, position, and velocity from interference fringes.

Interferometric synthetic-aperture radar

Interferometric synthetic-aperture radar (InSAR) is a remote-sensing method comparing radar images from repeated satellite passes to map millimeter-scale ground deformation from earthquakes, volcanoes, and subsidence.

Interferometric visibility

Interferometric visibility, also called fringe visibility or fringe contrast, is a dimensionless measure of the contrast of an interference pattern, ranging from 0 to 1.

Interferometry

Interferometry is a family of measurement techniques that extract information from the superposition of two or more waves, most often light, and ranks among the most sensitive forms of measurement available.

Interferon alfa-2b

Interferon alfa-2b (Intron A) is a recombinant form of human alpha interferon, approved in 1986 for hairy cell leukemia and used to treat hepatitis B and C and several cancers.

Intergalactic travel

Intergalactic travel, also called intergalactic space travel, is the hypothetical movement of spacecraft between galaxies; distances of hundreds of thousands to millions of light-years place it far beyond current engineering.

Intergovernmental Oceanographic Commission

The Intergovernmental Oceanographic Commission (IOC) of UNESCO, established in 1960, is the United Nations' lead body for ocean science, coordinating research, ocean observation, and tsunami warning systems.

Interim analysis

An interim analysis is a pre-planned assessment of outcome data collected so far in a clinical trial, used for safety, efficacy, or futility, typically under group sequential designs.

Interior algebra

An interior algebra, also known as a closure algebra or topo-boolean algebra, is a Boolean algebra with an interior operator; McKinsey and Tarski introduced the structure in 1944.

Interior Schwarzschild metric

The interior Schwarzschild metric, or Schwarzschild fluid solution, is an exact solution of the Einstein field equations for the gravitational field inside a uniform-density star.

Interior-point method

The interior-point method, or interior-point algorithm, is an optimization method that solves constrained problems by traveling through the feasible region's interior, made practical by Karmarkar's 1984 algorithm.

Interlayer charge transfer

Interlayer charge transfer is the ultrafast movement of electrons or holes between stacked atomic layers in van der Waals heterostructures, driven by type-II band alignment and producing long-lived interlayer excitons.

Interlayer exciton

An interlayer exciton is a bound electron–hole pair whose charges sit in different layers of a van der Waals heterostructure, giving it a long lifetime and a permanent electric dipole.

Interlayer exciton condensate in MoTe2 bilayers

An interlayer exciton condensate in MoTe2 bilayers is a macroscopic quantum state where electrons and holes in different molybdenum ditelluride layers share one collective state.

Interlayer exciton condensation

Interlayer exciton condensation is the formation of a macroscopic quantum state in which bound electron–hole pairs in separate layers of a bilayer share one coherent state, behaving like a superconductor with excitons instead of Cooper pairs.

Interlayer excitons in van der Waals heterostructures

Interlayer excitons are bound electron-hole pairs whose electron and hole sit in different atomic layers of a van der Waals heterostructure, giving long lifetimes and electric-field tunability.

Intermediate growth

Intermediate growth is the property of a finitely generated group growing faster than any polynomial but slower than any exponential, first constructed by Rostislav Grigorchuk in 1983.

Intermediate logic

An intermediate logic, also called a superintuitionistic logic, is a consistent set of propositional formulas containing intuitionistic propositional calculus and contained in classical logic; Gödel showed in 1932 that infinitely many exist.

Intermediate polar

An intermediate polar, also called a DQ Herculis star, is a cataclysmic variable in which a magnetic white dwarf accretes from a companion while spinning faster than the orbit.

Intermediate value theorem

The intermediate value theorem, also known as Bolzano's theorem or the Cauchy–Bolzano theorem, states that a continuous real function on a closed interval takes every value between its endpoint values.

Intermediate-mass black hole

An intermediate-mass black hole (IMBH) is a black hole of roughly 100 to 100,000 solar masses, between stellar-mass and supermassive black holes; candidates remain debated, with GW190521 the strongest evidence.

Intermittency

Intermittency is a behavior in nonlinear dynamics where long laminar, nearly periodic phases are interrupted by chaotic bursts, described by Pomeau and Manneville in 1980.

Intermolecular force

Intermolecular forces, also called intermolecular interactions or nonbonded interactions, are attractive or repulsive forces between molecules not involving chemical bonds, including dispersion, dipole–dipole, and hydrogen bonds.