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Lewis J. Fetters
Lewis J. Fetters (1936–2023) was an American polymer chemist, professor at the University of Akron from 1967 to 1983 and then a Senior Research Associate at Exxon Research and Engineering.
Lewis Morris Rutherfurd
Lewis Morris Rutherfurd (1816–1892) was an American amateur astronomer who pioneered astronomical photography and stellar spectroscopy, made superior diffraction gratings, and was an original National Academy of Sciences member.
Lewis number
The Lewis number is a dimensionless number, the ratio of thermal diffusivity to mass diffusivity, used in simultaneous heat and mass transfer and named for Warren Kendall Lewis.
Lewis structure
A Lewis structure, also called an electron dot structure, is a diagram showing a molecule's valence electrons as dots, with shared pairs drawn as covalent bonds.
Lexicographic order
Lexicographic order, also called lexical or dictionary order, is a way of ordering sequences by comparing them position by position, deciding at the first position where they differ.
LF (logical framework)
LF, short for the Edinburgh Logical Framework, is a typed lambda-calculus with dependent types designed as a meta-language for defining logics, presented by Harper, Honsell, and Plotkin in 1987.
LHAASO
LHAASO (高海拔宇宙线观测站), the Large High Altitude Air Shower Observatory, is a Chinese cosmic-ray and gamma-ray observatory on Mt. Haizi in Sichuan Province at 4,410 meters.
Lhasa terrane
The Lhasa terrane is a continental fragment that makes up southern Tibet and was the last crustal block to accrete to Eurasia before India collided with it.
LHCb experiment
LHCb (Large Hadron Collider beauty) is a particle physics experiment at CERN's Large Hadron Collider investigating why the universe holds matter but almost no antimatter, known for discovering pentaquarks in 2015.
LHCb Upgrade I
LHCb Upgrade I is the first major upgrade of the LHCb experiment at CERN, operating since 2022 with a fully software trigger at five times its previous luminosity.
LHCb Upgrade II
LHCb Upgrade II is the planned second major upgrade of the LHCb experiment at CERN, to be installed during Long Shutdown 4 for High-Luminosity LHC flavor physics.
Li (里) (unit)
The li, also known as the Chinese mile (里), is a traditional Chinese unit of distance standardized as exactly 500 meters, though its length varied across dynasties.
Li Ye (mathematician)
Li Ye (李冶, 1192–1279) was a Chinese mathematician and writer, one of the four great mathematicians of the Song–Yuan period, who wrote the earliest surviving works on tianyuan shu.
Liang (mass)
The liang (两, 两), also called the tael or Chinese ounce, is a traditional Chinese unit of mass, 50 grams in mainland China and about 37.5 to 37.8 grams elsewhere.
Liang Fu
Liang Fu (傅亮) is a Chinese-American condensed matter physicist and Professor of Physics at MIT, known for the theoretical prediction of topological insulators and Majorana fermion proposals.
Liang Jiang
Liang Jiang is a quantum information scientist and professor of molecular engineering at the University of Chicago since 2019, known for quantum error correction and fault-tolerant quantum computing.
Liar paradox
The Liar paradox, also known as Eubulides' paradox, is the semantic paradox of a sentence like "This sentence is not true" that seems both true and false.
Libai Huang
Libai Huang is a physical chemist, Tarpo Professor at Purdue University, known for ultrafast microscopy that images exciton and hot-carrier transport in perovskites and 2D materials.
Liber Abaci
Liber Abaci, also spelled Liber Abbaci, is a 1202 Latin treatise by Leonardo Pisano, known as Fibonacci, that taught calculation with Hindu-Arabic numerals and posed the rabbit problem behind the Fibonacci sequence.
Libet experiment
The Libet experiment is a 1983 study by Benjamin Libet at UC San Francisco that found brain activity precedes conscious awareness of the urge to move.
Libra (astrology)
Libra (तुला) is the seventh zodiac sign in Western astrology, a cardinal air sign ruled by Venus, symbolized by scales, and associated with balance and partnership.
Libra (constellation)
Libra is a faint zodiacal constellation of the southern sky representing the scales, lying on the ecliptic between Virgo and Scorpius, and best seen in June.
Library synthesis (chemistry)
Library synthesis is a set of chemistry methods for making large collections of structurally related compounds, as equimolar mixtures or discrete arrays, for screening many candidates at once.
Lichtenberg figure
The Lichtenberg figure, also called a beam tree or lightning flower, is a branching electrical discharge pattern named for Georg Christoph Lichtenberg, who discovered it in 1777.
Lick Observatory
Lick Observatory is a University of California astronomical observatory on Mount Hamilton near San Jose, founded in 1888 and the world's first permanently staffed mountain-top observatory.
Lidar
Lidar, also called LADAR or laser radar, is an active remote sensing method that measures distances with laser pulses to produce precise three-dimensional maps of terrain.
Lidar bathymetry
Lidar bathymetry is a remote sensing method that maps shallow seafloor depth by firing green laser pulses from aircraft, reaching roughly 50 m in clear coastal water.
Lie algebra
A Lie algebra is a vector space with a bilinear, antisymmetric Lie bracket satisfying the Jacobi identity, recording the infinitesimal behavior of continuous symmetry groups, named after Sophus Lie.
Lie algebra cohomology
Lie algebra cohomology, also called cohomology of Lie algebras, is a cohomology theory for Lie algebras introduced by Élie Cartan in 1929, computed via the Chevalley–Eilenberg complex.
Lie algebra extension
A Lie algebra extension is a Lie algebra fitting a short exact sequence, with splitting, central extensions, and classification by Lie algebra cohomology, founded by Chevalley and Eilenberg in 1948.