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Encyclopedia > Electron
Composition: Electron Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density Elementary particle Fermion Lepton First Gravity, Electromagnetic, Weak Positron G. Johnstone Stoney (1874) J.J. Thomson (1897) e−, β− 9.109 382 15(45) × 10–31 kg[1] 5.485 799 09(27) × 10–4 u Electron can refer to the following things: A subatomic particle - see electron A debit card - see Visa Electron An 8-bit computer made by Acorn Computers Ltd - see Acorn Electron This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Look up e-, i-, cyber-, virtual in Wiktionary, the free dictionary. ... Image File history File links HAtomOrbitals. ... Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. ... In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... In particle physics, fermions are particles with half-integer spin, such as protons and electrons. ... In physics, a lepton is a particle with spin-1/2 (a fermion) that does not experience the strong interaction (that is, the strong nuclear force). ... In particle physics, a generation is a division of the elementary particles. ... A fundamental interaction or fundamental force is a mechanism by which particles interact with each other, and which cannot be explained in terms of another interaction. ... Gravity is a force of attraction that acts between bodies that have mass. ... Electromagnetic interaction is a fundamental force of nature and is felt by charged leptons and quarks. ... The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four fundamental interactions of nature. ... Corresponding to most kinds of particle, there is an associated antiparticle with the same mass and opposite charges. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... George Johnstone Stoney (1826-1911) was an Irish physicist. ... Sir Joseph John Thomson, OM , FRS (December 18, 1756 â€“ August 30, 1940) often known as J. J. Thomson, was an English physicist, the discoverer of the electron. ... The invariant mass or intrinsic mass or proper mass or just mass is a measurement or calculation of the mass of an object that is the same for all frames of reference. ... â€œKgâ€ redirects here. ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... 1⁄1822.888 4843(11) u The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... 0.510 998 918(44) MeV/c2 –1.602 176 487(40) × 10–19 C[2] ½

The electron is a fundamental subatomic particle that carries a negative electric charge. It is a spin-½ lepton that participates in electromagnetic interactions, and its mass is less than one thousandth of that of the smallest atom.Its electric charge is defined by convention to be negative, with a value of −1 in atomic units. Together with atomic nuclei, electrons make up atoms; their interaction with adjacent nuclei is the main cause of chemical bonding. The electronvolt (symbol eV) is a unit of energy. ... The speed of light in vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... The coulomb (symbol: C) is the SI unit of electric charge. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ... In particle physics, an elementary particle is a particle of which other, larger particles are composed. ... Helium atom (schematic) Showing two protons (red), two neutrons (green) and two electrons (yellow). ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... In quantum mechanics, spin is an intrinsic property of all elementary particles. ... In physics, a lepton is a particle with spin-1/2 (a fermion) that does not experience the strong interaction (that is, the strong nuclear force). ... Electromagnetic interaction is a fundamental force of nature and is felt by charged leptons and quarks. ... For other uses, see Atom (disambiguation). ... Atomic units (au) form a system of units convenient for electromagnetism, atomic physics, and quantum electrodynamics, especially when the focus is on the properties of electrons. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... In chemistry, a chemical bond is the force which holds together atoms in molecules or crystals. ...

## Contents

The name "electron" comes from the Greek word for amber, ήλεκτρον. This material played an essential role in the discovery of electrical phenomena. The ancient Greeks knew, for example, that rubbing a piece of amber with fur left an electric charge on its surface, which could then create sparks. For more about the history of the term electricity, see History of electricity. This article or section is in need of attention from an expert on the subject. ... The history of electricity, that is the human understanding thereof, dates back to the ancient Greek and Parthian civilizations, over two thousand years ago. ...

The electron as a unit of charge in electrochemistry was posited by G. Johnstone Stoney in 1874, who also coined the term electron in 1894. George Johnstone Stoney (1826-1911) was an Irish physicist. ...

In this paper an estimate was made of the actual amount of this most remarkable fundamental unit of electricity, for which I have since ventured to suggest the name electron.

Stoney, George Johnstone (October 1894). "Of the "Electron," or Atom of Electricity". Philosophical Magazine 38 (5): 418-420.

During the late 1890s a number of physicists posited that electricity could be conceived of as being made of discrete units, which were given a variety of names, but their reality had not been confirmed in a compelling way. George Johnstone Stoney (February 15, 1826 â€“ July 5, 1911) was an Irish physicist. ... The Philosophical Magazine is arguably the worldâ€™s oldest commercially published scientific journal. ...

The discovery that the electron was a subatomic particle was made in 1897 by J.J. Thomson at the Cavendish Laboratory at Cambridge University, while he was studying cathode ray tubes. A cathode ray tube is a sealed glass cylinder in which two electrodes are separated by a vacuum. When a voltage is applied across the electrodes, cathode rays are generated, causing the tube to glow. Through experimentation, Thomson discovered that the negative charge could not be separated from the rays (by the application of magnetism), and that the rays could be deflected by an electric field. He concluded that these rays, rather than being waves, were composed of negatively charged particles he called "corpuscles". He measured their mass-to-charge ratio and found it to be over a thousand times smaller than that of a hydrogen ion, suggesting that they were either very highly charged or very small in mass. Later experiments by other scientists upheld the latter conclusion. Their mass-to-charge ratio was also independent of the choice of cathode material and the gas originally in the vacuum tube. This led Thomson to conclude that they were universal among all materials. Helium atom (schematic) Showing two protons (red), two neutrons (green) and two electrons (yellow). ... Sir Joseph John Thomson, OM , FRS (December 18, 1756 â€“ August 30, 1940) often known as J. J. Thomson, was an English physicist, the discoverer of the electron. ... Plaque, at old site Entrance, old site, Free School Lane The Cavendish Laboratory is the University of Cambridges Department of Physics, and is part of the universitys School of Physical Sciences. ... The University of Cambridge (often Cambridge University), located in Cambridge, England, is the second-oldest university in the English-speaking world and has a reputation as one of the worlds most prestigious universities. ... Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT: 1. ...

The electron's charge was carefully measured by R. A. Millikan in his oil-drop experiment of 1909. Not to be confused with Robert S. Mulliken. ... The purpose of Robert Millikan and Harvey Fletchers oil-drop experiment (1909) was to measure the electric charge of the electron. ...

The periodic law states that the chemical properties of elements largely repeat themselves periodically and is the foundation of the periodic table of elements. The law itself was initially explained by the atomic mass of the element. However, as there were anomalies in the periodic table, efforts were made to find a better explanation for it. In 1913, Henry Moseley introduced the concept of the atomic number and explained the periodic law in terms of the number of protons each element has. In the same year, Niels Bohr showed that electrons are the actual foundation of the table. In 1916, Gilbert Newton Lewis explained the chemical bonding of elements by electronic interactions. In the beginning People have known about basic chemical elements such as gold, silver, and copper from antiquity, as these can all be discovered in nature in native form and are relatively simple to mine with primitive tools. ... â€œThe Periodic Tableâ€ redirects here. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... Henry Moseley at work. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... In the beginning People have known about basic chemical elements such as gold, silver, and copper from antiquity, as these can all be discovered in nature in native form and are relatively simple to mine with primitive tools. ... Niels Henrik David Bohr (October 7, 1885 â€“ November 18, 1962) was a Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in 1922. ... Lewis in the Berkeley Lab Gilbert Newton Lewis (October 23, 1875-March 23, 1946) was a famous physical chemist. ...

## Classification

The electron is in the class of subatomic particles called leptons, which are believed to be fundamental particles. In physics, a lepton is a particle with spin-1/2 (a fermion) that does not experience the strong interaction (that is, the strong nuclear force). ... In particle physics, an elementary particle is a particle of which other, larger particles are composed. ...

As with all particles, electrons can also act as waves. This is called the wave-particle duality, also known by the term complementarity coined by Niels Bohr and can be demonstrated using the double-slit experiment. In physics, wave-particle duality holds that light and matter exhibit properties of both waves and of particles. ... // In physics, complementarity is a basic principle of quantum theory closely identified with the Copenhagen interpretation, and refers to effects such as the wave-particle duality, in which different measurements made on a system reveal it to have either particle-like or wave-like properties. ... Niels Henrik David Bohr (October 7, 1885 â€“ November 18, 1962) was a Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in 1922. ... Double-slit diffraction and interference pattern The double-slit experiment consists of letting light diffract through two slits, which produces fringes or wave-like interference patterns on a screen. ...

The antiparticle of an electron is the positron, which has the same mass but positive rather than negative charge. The discoverer of the positron, Carl D. Anderson, proposed calling standard electrons negatrons, and using electron as a generic term to describe both the positively and negatively charged variants. This usage never caught on and is rarely, if ever, encountered today. The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... Carl Anderson at LBNL 1937 Carl David Anderson (3 September 1905 â€“ 11 January 1991) was a U.S. experimental physicist. ...

## Properties and behavior

Electrons have an electric charge of −1.6022 × 10−19 coulomb, a mass of 9.11 × 10−31 kg based on charge/mass measurements and a relativistic rest mass of about 0.511 MeV/c². The mass of the electron is approximately 1/1836 of the mass of the proton. The common electron symbol is e.[1] Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... The coulomb (symbol: C) is the SI unit of electric charge. ... (Redirected from 1 E-31 kg) Categories: Orders of magnitude (mass) ... Albert Einsteins theory of relativity is a set of two theories in physics: special relativity and general relativity. ... The term mass in special relativity is used in a couple of different ways, occasionally leading to a great deal of confusion. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... The speed of light in vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... For other uses, see Proton (disambiguation). ...

According to quantum mechanics, electrons can be represented by wavefunctions, from which a calculated probabilistic electron density can be determined. The orbital of each electron in an atom can be described by a wavefunction. Based on the Heisenberg uncertainty principle, the exact momentum and position of the actual electron cannot be simultaneously determined. This is a limitation which, in this instance, simply states that the more accurately we know a particle's position, the less accurately we can know its momentum, and vice versa. For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... This article discusses the concept of a wavefunction as it relates to quantum mechanics. ... Electron density is the measure of the probability of an electron being present at a specific location. ... In chemistry, an atomic orbital is the region in which an electron may be found around a single atom. ... In quantum physics, the Heisenberg uncertainty principle, sometimes called the Heisenberg indeterminacy principle, expresses a limitation on accuracy of (nearly) simultaneous measurement of observables such as the position and the momentum of a particle. ... This article is about momentum in physics. ...

The electron has spin ½ and is a fermion (it follows Fermi-Dirac statistics). In addition to its intrinsic angular momentum, an electron has an intrinsic magnetic moment along its spin axis. In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ... In particle physics, fermions are particles with half-integer spin, such as protons and electrons. ... Fermi-Dirac distribution as a function of Îµ/Î¼ plotted for 4 different temperatures. ... A bar magnet. ...

Electrons in an atom are bound to that atom; electrons moving freely in vacuum, space or certain media are free electrons that can be focused into an electron beam. When free electrons move, there is a net flow of charge, this flow is called an electric current. The drift velocity of electrons in metal wires is on the order of mm/hour. However, the speed at which a current at one point in a wire causes a current in other parts of the wire is typically 75% of light speed. A charged particle beam is a group of electrically charged particles that have approximately the same kinetic energy and move in approximately the same direction. ... A net flow network is a mere simplification notation over the standard positive flow network. ... Electric current is the flow (movement) of electric charge. ... The drift velocity is the average velocity that a particle, such as an electron, attains due to an electric field. ... Velocity of Propagation (VoP) is a parameter that characterizes the speed at which an electrical or radio signal passes through a medium. ...

In some superconductors, pairs of electrons move as Cooper pairs in which their motion is coupled to nearby matter via lattice vibrations called phonons. The distance of separation between Cooper pairs is roughly 100 nm. (Rohlf, J.W.) Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ... A Cooper pair is the name given to electrons that are bound together in a certain manner first described by Leon Cooper. ... Normal modes of vibration progression through a crystal. ...

A body has an electric charge when that body has more or fewer electrons than are required to balance the positive charge of the nuclei. When there is an excess of electrons, the object is said to be negatively charged. When there are fewer electrons than protons, the object is said to be positively charged. When the number of electrons and the number of protons are equal, their charges cancel each other and the object is said to be electrically neutral. A macroscopic body can develop an electric charge through rubbing, by the phenomenon of triboelectricity. Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... For other uses, see Proton (disambiguation). ... Macroscopic is commonly used to describe physical objects that are measurable and observable by the naked eye. ... For other uses, see Phenomena (disambiguation). ... The triboelectric effect is an electrical phenomenon where certain materials become electrically charged after coming into contact with another, different, material. ...

When electrons and positrons collide, they annihilate each other and produce pairs of high energy photons or other particles. On the other hand, high-energy photons may transform into an electron and a positron by a process called pair production, but only in the presence of a nearby charged particle, such as a nucleus. The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... Electron-positron annihilation is the process that occurs when an electron (which is matter) and a positron (which is antimatter) collide. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... Pair production refers to the creation of an elementary particle and its antiparticle, usually from a photon (or another neutral boson). ...

The electron is currently described as a fundamental particle or an elementary particle. It has no substructure. Hence, for convenience, it is usually defined or assumed to be a point-like mathematical point charge, with no spatial extension. However, when a test particle is forced to approach an electron, we measure changes in its properties (charge and mass). This effect is common to all elementary particles: Current theory suggests that this effect is due to the influence of vacuum fluctuations in its local space, so that the properties measured from a significant distance are considered to be the sum of the bare properties and the vacuum effects (see renormalization). In particle physics, an elementary particle is a particle of which other, larger particles are composed. ... In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... In particle physics, preons are postulated point-like particles, conceived to be subcomponents of quarks and leptons. ... This page is a candidate for speedy deletion. ... The word space has many meanings, including: Physics The definition of space in physics is contentious. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... This article or section is in need of attention from an expert on the subject. ... In the description of the interaction between elementary particles in quantum field theory, a virtual particle is a temporary elementary particle, used to describe an intermediate stage in the interaction. ... Figure 1. ...

The classical electron radius is 2.8179 × 10−15 m. This is the radius that is inferred from the electron's electric charge, by using the classical theory of electrodynamics alone, ignoring quantum mechanics. Classical electrodynamics (Maxwell's electrodynamics) is the older concept that is widely used for practical applications of electricity, electrical engineering, semiconductor physics, and electromagnetics; quantum electrodynamics, on the other hand, is useful for applications involving modern particle physics and some aspects of optical, laser and quantum physics. The classical electron radius, also known as the Compton radius or the Thomson scattering length is based on a classical (i. ... This article is about the unit of length. ... Classical electrodynamics (or classical electromagnetism) is a theory of electromagnetism that was developed over the course of the 19th century, most prominently by James Clerk Maxwell. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... James Clerk Maxwell (13 June 1831 â€“ 5 November 1879) was a Scottish mathematician and theoretical physicist from Edinburgh, Scotland, UK. His most significant achievement was aggregating a set of equations in electricity, magnetism and inductance â€” eponymously named Maxwells equations â€” including an important modification (extension) of the AmpÃ¨res... Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. ...

Based on current theory, the speed of an electron can approach, but never reach, c (the speed of light in a vacuum). This limitation is attributed to Einstein's theory of special relativity which defines the speed of light as a constant within all inertial frames. However, when relativistic electrons are injected into a dielectric medium, such as water, where the local speed of light is significantly less than c, the electrons will (temporarily) be traveling faster than light in the medium. As they interact with the medium, they generate a faint bluish light, called Cherenkov radiation. The speed of light in vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ... In physics, an inertial frame of reference, or inertial frame for short (also descibed as absolute frame of reference), is a frame of reference in which the observers move without the influence of any accelerating or decelerating force. ... Albert Einsteins theory of relativity is a set of two theories in physics: special relativity and general relativity. ... A dielectric, or electrical insulator, is a substance that is highly resistant to electric current. ... Cherenkov radiation glowing in the core of a TRIGA reactor Cherenkov radiation (also spelled Cerenkov or sometimes ÄŒerenkov) is electromagnetic radiation emitted when a charged particle passes through an insulator at a speed greater than the speed of light in that medium. ...

The effects of special relativity are based on a quantity known as γ or the Lorentz factor. γ is a function of v, the velocity of the particle. It is defined as: For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ... Gamma (uppercase Î“, lowercase Î³) is the third letter of the Greek alphabet. ... It has been suggested that Lorentz term be merged into this article or section. ...

$gamma = frac{1}{sqrt{1 - left (frac{v^{2}}{c^{2}}right )}}$

The energy necessary to accelerate a particle is:

$left(gamma - 1right)m_e c^2$

For example, the Stanford linear accelerator can accelerate an electron to roughly 51 GeV [1]. This gives a gamma of 100,000, since the rest mass of an electron is 0.51 MeV/c² (the relativistic mass of this electron is 100,000 times its rest mass). Solving the equation above for the speed of the electron (and using an approximation for large γ) gives: The Stanford Linear Accelerator Center (SLAC) is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Department of Energy Office of Science. ... Acceleration is the time rate of change of velocity, and at any point on a v_t graph, it is given by the gradient of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of velocity. ... The term mass in special relativity can be used in different ways, occasionally leading to confusion. ...

$v = left(1-frac {1} {2} gamma ^{-2}right)c = 0.999,999,999,95,c.$

## In practice

### In the universe

Scientists believe that the number of electrons existing in the known universe is at least 1079. This number amounts to an average density of about one electron per cubic metre of space. Astronomers have estimated that 90% of the mass of atoms in the universe is hydrogen, which is made of one electron and one proton. For other uses, see Universe (disambiguation). ... The cubic meter (symbol mÂ³) is the SI derived unit of volume. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...

### In industry

Electron beams are used in welding, lithography, scanning electron microscopes and transmission electron microscopes. LEED and RHEED are also important tools where electrons are used. A charged particle beam is a group of electrically charged particles that have approximately the same kinetic energy and move in approximately the same direction. ... Electron beam welding is a welding process where the energy to melt the material is applied by an electron beam. ... // Conventional electron-beam lithography The practice of using a beam of electrons to generate patterns on a surface is known as Electron beam lithography. ... SEM Cambridge S150 at Geological Institute, University Kiel, 1980 SEM opened sample chamber The scanning electron microscope (SEM) is a type of electron microscope capable of producing high-resolution images of a sample surface. ... Transmission electron microscopy (TEM) is an imaging technique whereby a beam of electrons is focused onto a specimen causing an enlarged version to appear on a fluorescent screen or layer of photographic film (see electron microscope), or can be detected by a CCD camera. ... Low Energy Electron Diffraction (or LEED) is a technique used to characterize the structures of surfaces. ... RHEED stands for Reflection High Energy Electron diffraction. ...

They are also at the heart of cathode ray tubes, which are used extensively as display devices in laboratory instruments, computer monitors and television sets. In photomultiplier tubes, one photon strikes the photocathode, initiating an avalanche of electrons that produces a detectable current. Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT: 1. ... Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing still or moving images generated by a computer and processed by a graphics card. ... Television set may refer to: Television, a device to display television programs Television studio, an installation in which television or video productions take place Set construction, theatrical scenery This is a disambiguation page: a list of articles associated with the same title. ... Photomultipliers, or photomultiplier tubes (PMT) are extremely sensitive detectors of light in the ultraviolet, visible and near infrared. ...

### In the laboratory

Electron microscopes are used to magnify details up to 500,000 times. Quantum effects of electrons are used in Scanning tunneling microscope to study features at the atomic scale. An electron microscope is a type of microscope that uses electrons to illuminate and create an image of a specimen. ... Image of reconstruction on a clean Au(100) surface. ...

### In medicine

In radiation therapy, electron beams are used for treatment of superficial tumours. Clinac 2100 C100 accelerator Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... Superficial is a general term meaning regarding the surface, often metaphorically. ...

## In theory

In relativistic quantum mechanics, the electron is described by the Dirac Equation which defines the electron as a (mathematical) point. In quantum field theory, the reaction of the electron is described by quantum electrodynamics (QED), a U(1) gauge theory. In Dirac's model, an electron is defined to be a mathematical point, a point-like, charged "bare" particle surrounded by a sea of interacting pairs of virtual particles and antiparticles. These provide a correction of just over 0.1% to the predicted value of the electron's gyromagnetic ratio from exactly 2 (as predicted by Dirac's single-particle model). The extraordinarily precise agreement of this prediction with the experimentally determined value is viewed as one of the great achievements of modern physics.[3] For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... In physics, the Dirac equation is a relativistic quantum mechanical wave equation formulated by British physicist Paul Dirac in 1928 and provides a description of elementary spin-Â½ particles, such as electrons, consistent with both the principles of quantum mechanics and the theory of special relativity. ... Quantum field theory (QFT) is the quantum theory of fields. ... Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. ... In physics, gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ... In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... Corresponding to most kinds of particle, there is an associated antiparticle with the same mass and opposite charges. ... In physics, the gyromagnetic ratio (also sometimes known as the magnetogyric ratio in other disciplines) of a particle or system is the ratio of its magnetic dipole moment to its angular momentum. ...

In the Standard Model of particle physics, the electron is the first-generation charged lepton. It forms a weak isospin doublet with the electron neutrino; these two particles interact with each other through both the charged and neutral current weak interaction. The electron is very similar to the two more massive particles of higher generations, the muon and the tau lepton, which are identical in charge, spin, and interaction but differ in mass. The Standard Model of Fundamental Particles and Interactions For the Standard Model in Cryptography, see Standard Model (cryptography). ... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... In particle physics, a generation is a division of the elementary particles. ... In physics, a lepton is a particle with spin-1/2 (a fermion) that does not experience the strong interaction (that is, the strong nuclear force). ... The weak isospin in theoretical physics parallels the idea of the isospin under the strong interaction, but applied under the weak interaction. ... The neutrino is an elementary particle. ... The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four fundamental interactions of nature. ... The muon (from the letter mu (Î¼)--used to represent it) is an elementary particle with negative electric charge and a spin of 1/2. ... The tau lepton (often called the tau or occasionally the tauon) is a negatively charged elementary particle with a lifetime of 3Ã—10âˆ’13 seconds and a high mass of 1777 MeV (compared to 939 MeV for protons and 0. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ... A fundamental interaction or fundamental force is a mechanism by which particles interact with each other, and which cannot be explained in terms of another interaction. ...

The antimatter counterpart of the electron is the positron. The positron has the same amount of electrical charge as the electron, except that the charge is positive. It has the same mass and spin as the electron. When an electron and a positron meet, they may annihilate each other, giving rise to two gamma-ray photons emitted at roughly 180° to each other. If the electron and positron had negligible momentum, each gamma ray will have an energy of 0.511 MeV. See also Electron-positron annihilation. For other senses of this term, see antimatter (disambiguation). ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... Annihilation is defined as total destruction or complete obliteration of an object;[1] having its root in the Latin nihil (nothing). ... This article is about electromagnetic radiation. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... Electron-positron annihilation is the process that occurs when an electron (which is matter) and a positron (which is antimatter) collide. ...

Electrons are a key element in electromagnetism, a theory that is accurate for macroscopic systems, and for classical modelling of microscopic systems. Electromagnetism is the physics of the electromagnetic field: a field which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles. ...

Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... In theoretical physics, a particles self-energy represents the contribution to the particles energy or effective mass due to interactions between the particle and the system it is apart of. ... In quantum physics, if we expand about the Fock vacuum, the true vacuum contains short-lived virtual particle-antiparticle pairs which are created in pairs out of the Fock vacuum and then annihilate each other. ... In quantum electrodynamics, the vertex function is the one particle irreducible correlation function involving &#968;, and the vector potential A. It is unfortunate that the effective action &#915;eff and the vertex function &#915;&#956; happen to be described by the same letter. ... In quantum field theory, the Gupta-Bleuler formalism is a way of quantizing the electromagnetic field. ... In the physics of gauge theories, gauge fixing (also called choosing a gauge) denotes a mathematical procedure for coping with redundant degrees of freedom in field variables. ... In quantum field theory a Ward-Takahashi identity is nowadays used to designate an identity between correlation functions that follows from symmetries, either global or gauged, of the theory, and which remains valid after renormalization. ... In physics, Compton scattering or the Compton effect, is the decrease in energy (increase in wavelength) of an X-ray or gamma ray photon, when it interacts with matter. ... In quantum electrodynamics, Bhabha scattering is the electron positron scattering process represented by . ... MÃ¸ller scattering is the name given to electron-electron scattering in Quantum Field Theory. ... In quantum electrodynamics, anomalous magnetic moment of a particle is a contribution of effects of quantum mechanics, expressed by Feynman diagrams with loops, to the magnetic moment of that particle. ... (helpÂ· info), (from the German bremsen, to brake and Strahlung, radiation, thus, braking radiation), is electromagnetic radiation produced by the acceleration of a charged particle, such as an electron, when deflected by another charged particle, such as an atomic nucleus. ... Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron, bound together into an exotic atom. The orbit of the two particles and the set of energy levels is similar to that of the hydrogen atom (electron and proton). ...

## Notes

1. ^ a b All masses are 2006 CODATA values accessed via the NIST’s electron mass page. The fractional version’s denominator is the inverse of the decimal value (along with its relative standard uncertainty of 5.0 × 10–8)
2. ^ The electron’s charge is the negative of elementary charge (which is a positive value for the proton). CODATA value accessed via the NIST’s elementary charge page.
3. ^ *Griffiths, David J. (2004). Introduction to Quantum Mechanics (2nd ed.). Prentice Hall. ISBN 0-13-805326-X.

CODATA (Committee on Data for Science and Technology) was established in 1966 as an interdisciplinary committee of the International Council of Science (ICSU), formerly the International Council of Scientific Unions. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... CODATA (Committee on Data for Science and Technology) was established in 1966 as an interdisciplinary committee of the International Council of Science (ICSU), formerly the International Council of Scientific Unions. ...

• One-electron universe

The one-electron universe hypothesis, commonly associated with Richard Feynman, postulates that there exists only a single electron in the universe, propagating through space and time in such a way as to appear in many places simultaneously. ...

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