42,772 articles
Leica Microsystems
Leica Microsystems is a German microscope and scientific imaging manufacturer headquartered in Wetzlar, tracing its origins to an optical institute founded there in 1849, and owned by Danaher.
Leiden algorithm
The Leiden algorithm is a community detection method for large networks, created by Traag, Waltman, and van Eck at Leiden University in 2018 as a faster improvement on Louvain.
Leiden Declaration on Artificial Intelligence and Mathematics
The Leiden Declaration on Artificial Intelligence and Mathematics, published in June 2026, calls for action on AI's challenges to mathematics research and was endorsed by the International Mathematical Union.
Leidenfrost effect
The Leidenfrost effect is the levitation of a liquid on a cushion of its own vapor above a surface much hotter than its boiling point, first reported in 1756.
Leif Hammarström
Leif Hammarström, born 1964 in Uppsala, is a Swedish physical chemist and Professor of Chemical Physics at Uppsala University, known for proton-coupled electron transfer and artificial photosynthesis.
Leigh Canham
Leigh Canham (Leigh Trevor Canham) is a British solid state physicist who showed in 1990 that porous silicon emits visible red light, and later that silicon can be medically biodegradable.
Leimkuhler–Matthews method
The Leimkuhler–Matthews method is a numerical integrator for overdamped Langevin dynamics that modifies Euler–Maruyama by averaging consecutive Gaussian noise increments, giving second-order accuracy for invariant averages.
Leland John Haworth
Leland John Haworth (1904–1979) was an American experimental physicist who directed Brookhaven National Laboratory from 1948 to 1961 and the National Science Foundation from 1963 to 1969.
Lemniscate
The lemniscate of Bernoulli is a figure-eight plane curve, defined by a constant product of distances from two fixed points, published by Jacob Bernoulli in 1694.
Lemon battery
A lemon battery is a simple electrochemical cell made from a zinc nail and a copper strip inserted into a lemon, used to demonstrate how batteries work.
Lene V. Hau
Lene V. Hau, also known as Lene Vestergaard Hau, is a Danish physicist at Harvard who led experiments slowing light to 17 m/s in 1999 and stopping it in 2001.
Length
Length, also called the length dimension, is the measure of distance along a line, whose SI base unit, the meter, is defined by fixing the speed of light.
Length contraction
Length contraction, also called Lorentz contraction, is the special relativity effect by which an object moving relative to an observer is measured shorter along its direction of motion.
Length measurement
Length measurement, or distance measurement, determines the extent of an object or the separation of two points along a line, done at highest precision through laser interferometry.
Length of day variations
Length of day variations are millisecond changes in the Earth's actual rotation relative to the standard 86,400-second day, driven by tides, atmospheric winds, the liquid core, and climate change.
Lennard Fisk
Lennard Fisk is an American space physicist at the University of Michigan, known for his 1974 theory of anomalous cosmic rays and his service as a NASA associate administrator.
Lennard-Jones potential
The Lennard-Jones potential is a two-parameter mathematical model for the interaction energy between a pair of neutral atoms or molecules, and the most widely used pair potential in molecular simulations.
Lennart Carleson
Lennart Carleson, born 1928 in Stockholm, is a Swedish mathematician who proved Carleson's theorem on Fourier series in 1966, solved the corona problem, and received the 2006 Abel Prize.
Lennart Lindegren
Lennart Lindegren, born 1950 in Sweden, is a Swedish astronomer at Lund Observatory who established the data-reduction methods for ESA's Hipparcos and Gaia missions, sharing the 2022 Shaw Prize in Astronomy.
Lennart von Post
Ernst Jakob Lennart von Post (1884–1951) was a Swedish geologist who introduced the quantitative pollen diagram, reconstructing postglacial vegetation and climate history from fossil pollen in peat bogs.
Lennox Cowie
Lennox Cowie is a British astronomer at the University of Hawaii Institute for Astronomy, known for deep Keck surveys of faint galaxies and work on the submillimetre background.
Lens
A lens, or optical lens, is a piece of transparent material shaped to refract light and form images, used in magnifying glasses, cameras, and the human eye.
Lens flare
Lens flare is a family of image artifacts caused when bright light reflects, scatters, or diffracts inside a camera lens, appearing as haze, ghost shapes, or streaks.
Lens space
A lens space, written L(p,q), is a closed 3-dimensional manifold formed by gluing two solid tori, or as a quotient of the 3-sphere by a cyclic group.
Lense–Thirring precession
Lense–Thirring precession, or Lense–Thirring effect, is the frame-dragging precession of orbits and gyroscopes caused by a rotating body, first derived by Josef Lense and Hans Thirring in 1918.
Lenses
A lens is a transparent optical component of glass or plastic that refracts light to converge or diverge it, forming images in eyeglasses, cameras, microscopes, and telescopes.
Lensless holographic microscopy
Lensless holographic microscopy is a label-free imaging method that records in-line holograms directly on an image sensor without lenses, then reconstructs amplitude and phase images computationally.
Lenstra–Lenstra–Lovász lattice basis reduction algorithm
The Lenstra–Lenstra–Lovász (LLL) algorithm, introduced by Arjen Lenstra, Hendrik Lenstra, and László Lovász in 1982, transforms any lattice basis into a reduced basis with short, nearly orthogonal vectors in polynomial time.
Lent
Lent, the Lenten season, is a Christian penitential season of about 40 days of prayer, fasting, and almsgiving preparing for Easter, beginning on Ash Wednesday in the West.
Lenticular galaxy
A lenticular galaxy (Hubble type S0) has a bright bulge and a flattened disk like a spiral galaxy, but no spiral arms and little ongoing star formation.