Physical world and mathematics

Leonhard Euler

Leonhard Euler was a Swiss mathematician and physicist of the 18th century who introduced much of modern mathematical notation, including f(x), e, i, and π.

Leonhard Grill

Leonhard Grill is an Austrian physical chemist and professor at the University of Graz who studies single molecules on surfaces and won the first Nanocar Race in 2017.

Leonid Brekhovskikh (1917–2005) was a Soviet and Russian acoustical oceanographer who discovered the underwater sound channel in 1946 and wrote Waves in Layered Media, the standard reference on wave propagation in layered media.

Sep 20, 2026

Leonid Dubrovinsky

Leonid Dubrovinsky (born 1961) is a high-pressure mineral physicist and professor at the University of Bayreuth known for generating static pressures beyond 1 terapascal in the laboratory and synthesizing new materials there.

Leonid Keldysh

Leonid Keldysh (Леонид Келдыш) was a Soviet and Russian theoretical physicist at the Lebedev Institute in Moscow, known for the Keldysh diagram technique, the Keldysh parameter, and the Franz–Keldysh effect.

Leonid Levitov

Leonid S. Levitov is a Russian-born theoretical condensed matter physicist and professor of physics at MIT, known for leviton current pulses, graphene valley currents, and electron hydrodynamics.

Leonid Mandelstam

Leonid Isaakovich Mandelstam (Леонид Исаакович Мандельштам, 1879–1944) was a Soviet physicist who co-discovered the Raman effect in 1928 and founded the Moscow school of radiophysics and oscillation theory.

Leonid Vaserstein

Leonid Vaserstein is a Russian-born mathematician, emeritus professor at Penn State, known for the stable rank of rings and the Wasserstein distance used in machine learning.

Leonidas Alaoglu

Leonidas Alaoglu (1914–1981) was a Canadian-born mathematician, born in Red Deer, Alberta, to Greek parents, known for the Banach–Alaoglu theorem and a 1944 paper with Paul Erdős that left an open problem in number theory.

Leonids

The Leonids are an annual meteor shower peaking in mid-November, produced by debris from comet 55P/Tempel-Tuttle and radiating from Leo, capable of meteor storms every 33 years.

Leonor Michaelis

Leonor Michaelis (1875–1949) was a German-born biochemist and physician who, with Maud Menten, derived the Michaelis–Menten constant in 1913 and later worked at the Rockefeller Institute.

Leopold Gegenbauer

Leopold Gegenbauer (1849–1903) was an Austrian mathematician who held chairs at Czernowitz, Innsbruck, and Vienna, and is known for the Gegenbauer polynomials, which unify the Legendre and Chebyshev families.

Leopold Horner

Leopold Horner (1911–2005) was a German organic chemist and professor at the University of Mainz, namesake of the Horner–Wadsworth–Emmons olefination, a widely used reaction for forming carbon–carbon double bonds.

Leopold Infeld

Leopold Infeld (1898–1968) was a Polish theoretical physicist who co-authored the Born–Infeld theory, the Einstein–Infeld–Hoffmann equations, and the popular book The Evolution of Physics with Einstein.

Leopold Löwenheim

Leopold Löwenheim (1878–1957) was a German schoolteacher and mathematician in Berlin who proved in 1915 the first significant metalogical theorem, now known as the Löwenheim–Skolem theorem.

Leopold Ruzicka

Leopold Ruzicka (Leopold Ružička, 1887–1976) was a Croatian-born Swiss chemist at ETH Zurich who won the 1939 Nobel Prize in Chemistry for work on terpenes and synthesized testosterone.

Leopold Vietoris

Leopold Vietoris (1891–2002) was an Austrian mathematician at the University of Innsbruck whose name is attached to the Mayer–Vietoris sequence, the Vietoris–Begle theorem, and the Vietoris–Rips complex.

Leopoldo Máximo Falicov

Leopoldo Máximo Falicov (1933–1995) was an Argentine-born theoretical physicist who led the physics department at the University of California, Berkeley and introduced the Falicov–Kimball model of metal–insulator transitions in 1969.

Lepidocrocite

Lepidocrocite is an iron oxide hydroxide mineral, FeO(OH), dimorphous with goethite, that forms as a secondary oxidation product in soils, ore deposits, and rust layers on carbon steel.

Lepidolite

Lepidolite is a lithium-rich mica mineral, usually pink, red, or purple, that occurs almost exclusively in lithium-enriched granitic pegmatites and serves as a minor ore of lithium.

Leptogenesis

Leptogenesis is a proposed explanation for the matter-antimatter asymmetry of the Universe, in which heavy right-handed neutrino decays create a lepton asymmetry converted into a baryon asymmetry.

Lepton

A lepton is an elementary particle of matter that does not feel the strong nuclear force; the six leptons include the electron, muon, tau, and their neutrinos.

Lepton universality

Lepton universality, or lepton flavor universality (LFU), is a Standard Model principle that the electron, muon, and tau couple identically to electroweak gauge bosons, differing only in mass.

Leptonic emission

Leptonic emission is high-energy radiation produced directly by relativistic leptons, chiefly electrons and positrons, through synchrotron radiation, bremsstrahlung, and inverse Compton scattering, contrasted with hadronic emission from pion decay.

Leptoquark

A leptoquark is a hypothetical particle that couples to both a quark and a lepton, allowing the two to transform into each other; none has been observed.

Lepus (constellation)

Lepus, meaning the Hare in Latin, is a constellation south of the celestial equator just below Orion's feet, cataloged by Ptolemy in the 2nd century.

Leray spectral sequence

The Leray spectral sequence is a spectral sequence, introduced by Jean Leray in 1945 alongside sheaf theory, that computes the cohomology of a space from a continuous map's fibers.

LeRoy Apker Award

The LeRoy Apker Award is an annual American Physical Society prize recognizing outstanding undergraduate physics research in the United States, established in 1978 and given to two students each year.

Leroy Chang

Leroy Chang (张立纲, Zhang Ligang; 1936–2008) was a Chinese-born American condensed-matter physicist who spent three decades at IBM turning the semiconductor superlattice and resonant tunneling into working devices.