Physical world and mathematics

Elementary algebra

Elementary algebra, also known as college algebra or high school algebra, is the branch of mathematics that uses letters as variables to write and solve equations, taught in school and introductory college courses.

Elementary charge

The elementary charge, symbol e, is the magnitude of the charge carried by a single electron or proton, fixed exactly at 1.602176634 × 10⁻¹⁹ coulombs in the SI since 2019.

Elementary equivalence

Elementary equivalence, or elementarily equivalent structures, is a relation between structures of the same first-order language that satisfy exactly the same first-order sentences, formulated by Alfred Tarski in 1930.

Elementary function

An elementary function is a function built by repeated composition from constants, addition, multiplication, division, root extraction, and algebraic, exponential, logarithmic, and trigonometric functions and their inverses.

Elementary matrix

An elementary matrix, or elementary matrices collectively, is a square matrix made from the identity by one row operation: a swap, a scaling, or a row addition.

Elementary particle

An elementary particle, also called a fundamental particle, is a particle not made of simpler parts. In the Standard Model these include quarks, leptons, gauge bosons, and the Higgs boson.

Elementary reaction

An elementary reaction is a chemical reaction occurring in a single step through a single transition state, and elementary steps form a complex reaction's mechanism.

Elementary symmetric polynomial

An elementary symmetric polynomial σₖ is the sum of all products of k distinct variables x₁, ..., xₙ; by the fundamental theorem, every symmetric polynomial is uniquely a polynomial in them, a fact underlying Vieta's formulas.

Éléments de mathématique

Éléments de mathématique is a treatise on mathematics by Nicolas Bourbaki, a largely French collective, rebuilding modern mathematics axiomatically in ten books across roughly forty volumes.

Elena Aprile

Elena Aprile, born 1954, is an Italian experimental physicist at Columbia University who founded the XENON dark matter search in 2002 and leads it as spokesperson.

Elena Shevchenko

Elena V. Shevchenko is a nanoscientist, a staff scientist at Argonne National Laboratory since 2007, known for her 2006 Nature paper on binary nanoparticle superlattices.

Éléonore

Éléonore is an underground gold mine in Eeyou Istchee Baie-James, northern Quebec, which opened in 2014 and has been operated since 2025 by Dhilmar Ltd.

Éléonore Mine

The Éléonore Mine is an underground gold mine in the James Bay region of northern Quebec, on the Roberto deposit, in production since 2015 under Goldcorp.

Elephant's toothpaste

Elephant's toothpaste is a popular chemistry demonstration in which hydrogen peroxide, catalyzed by potassium iodide or yeast, erupts into a rapidly growing column of foam.

Elettra (synchrotron)

Elettra is a third-generation synchrotron light source in Basovizza, near Trieste, Italy, operating since 1993 at two electron energies and serving more than 1,200 visiting scientists a year.

Eli Pollak

Eli Pollak, born 1950 in Haifa, Israel, is an Israeli chemical physicist and professor at the Weizmann Institute of Science, known for solving the Kramers turnover problem in 1989.

Eli Rotenberg

Eli Rotenberg is a senior scientist at Lawrence Berkeley National Laboratory leading the ARPES program at the Advanced Light Source, studying quantum materials from quasicrystals to graphene.

Eli Terry

Eli Terry (1772–1852) was an American clockmaker of Plymouth, Connecticut, who converted clockmaking into a factory industry by mass-producing wooden movements with interchangeable parts, receiving the first US clock patent in 1797.

Eli Tziperman

Eli Tziperman is an Israeli-American climate and ocean dynamicist, a Harvard professor since 2003, known for showing that the El Niño cycle can behave chaotically.

Eli Waxman

Eli Waxman (born 1965) is an Israeli theoretical astrophysicist at the Weizmann Institute of Science, known for the Waxman–Bahcall bound and for leading the ULTRASAT ultraviolet satellite.

Eli Yablonovitch

Eli Yablonovitch is an electrical engineer and physicist at UC Berkeley who coined the term "photonic crystal" and created the 4n² light-trapping limit used in solar panels.

Eli Zeldov

Eli Zeldov (אלי זלדוב) is an Israeli condensed matter physicist at the Weizmann Institute of Science, known for inventing the SQUID-on-tip, a nanoscale probe imaging magnetic and thermal phenomena.

Eli Zysman‐Colman

Eli Zysman-Colman is Professor of Optoelectronic Materials at the University of St Andrews, known for organic TADF emitters used in OLEDs and for the spin-out SolOLED.

ELI-NP

ELI-NP, the Extreme Light Infrastructure – Nuclear Physics, is a research facility in Măgurele, near Bucharest, Romania, combining a 10 PW high-power laser with a gamma beam system.

Eliakim Hastings Moore (mathematician)

Eliakim Hastings Moore (1862–1932) was an American mathematician, first chair of mathematics at the University of Chicago from 1892, and president of the American Mathematical Society.

Elias James Corey

Elias James Corey, known as E. J. Corey, is an American organic chemist at Harvard who won the unshared 1990 Nobel Prize in Chemistry for his theory and methodology of organic synthesis.

Elias Loomis

Elias Loomis (1811–1889) was an American mathematician, astronomer, and meteorologist who taught at Western Reserve, New York University, and Yale, and published early synoptic weather maps in 1846.

Elias M. Stein

Elias M. Stein (1931–2018) was a Belgian-born American mathematician who spent 50 years at Princeton, shaped harmonic analysis, and won the Wolf Prize in 1999.

Elias Snitzer

Elias Snitzer (1925–2012) was an American physicist who invented the glass laser, the first optical fiber laser, and the first fiber amplifier, and later the double-clad fiber laser.