# Quantum electrodynamics

**QEDquantum electrodynamicelectromagneticQuantum Electrodynamicalelectrodynamicsextension to electrodynamicsprobability amplitudesQED theoryquantization of the electromagnetic fieldquantum**

In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics.wikipedia

491 Related Articles

### Quantum field theory

**quantum field theoriesquantum fieldquantum theory**

In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics.

Its development began in the 1920s with the description of interactions between light and electrons, culminating in the first quantum field theory — quantum electrodynamics.

### Precision tests of QED

**extremely accurate predictionstesthigh-precision atomic tests of quantum electrodynamics**

Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen.

Quantum electrodynamics (QED), a relativistic quantum field theory of electrodynamics, is among the most stringently tested theories in physics.

### Vacuum state

**quantum vacuumvacuumZero-point field**

In technical terms, QED can be described as a perturbation theory of the electromagnetic quantum vacuum.

The QED vacuum of quantum electrodynamics (or QED) was the first vacuum of quantum field theory to be developed.

### Paul Dirac

**DiracPaul Adrien Maurice DiracP. A. M. Dirac**

The first formulation of a quantum theory describing radiation and matter interaction is attributed to British scientist Paul Dirac, who (during the 1920s) was able to compute the coefficient of spontaneous emission of an atom.

Dirac made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics.

### Classical electromagnetism

**classical electrodynamicselectrodynamicsclassical**

QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.

For small distances and low field strengths, such interactions are better described by quantum electrodynamics.

### Electric charge

**chargeelectrical chargecharged**

QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.

The study of photon-mediated interactions among charged particles is called quantum electrodynamics.

### Perturbation theory (quantum mechanics)

**perturbation theoryperturbativeperturbation**

In technical terms, QED can be described as a perturbation theory of the electromagnetic quantum vacuum. However, further studies by Felix Bloch with Arnold Nordsieck, and Victor Weisskopf, in 1937 and 1939, revealed that such computations were reliable only at a first order of perturbation theory, a problem already pointed out by Robert Oppenheimer.

In the theory of quantum electrodynamics (QED), in which the electron–photon interaction is treated perturbatively, the calculation of the electron's magnetic moment has been found to agree with experiment to eleven decimal places.

### Arnold Nordsieck

**Nordsieck**

However, further studies by Felix Bloch with Arnold Nordsieck, and Victor Weisskopf, in 1937 and 1939, revealed that such computations were reliable only at a first order of perturbation theory, a problem already pointed out by Robert Oppenheimer.

He is best known for his work with Felix Bloch on the infrared problem in quantum electrodynamics.

### Hans Bethe

**Hans A. BetheBetheHans Albrecht Bethe**

A first indication of a possible way out was given by Hans Bethe in 1947, after attending the Shelter Island Conference.

Hans Albrecht Bethe (July 2, 1906 – March 6, 2005) was a German-American nuclear physicist who made important contributions to astrophysics, quantum electrodynamics and solid-state physics, and won the 1967 Nobel Prize in Physics for his work on the theory of stellar nucleosynthesis.

### Lamb shift

**shift**

Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen.

It was the harbinger of modern quantum electrodynamics developed by Julian Schwinger, Richard Feynman, Ernst Stueckelberg, Sin-Itiro Tomonaga and Freeman Dyson.

### Freeman Dyson

**Freeman J. DysonDysonFreeman John Dyson**

Based on Bethe's intuition and fundamental papers on the subject by Shin'ichirō Tomonaga, Julian Schwinger, Richard Feynman and Freeman Dyson, it was finally possible to get fully covariant formulations that were finite at any order in a perturbation series of quantum electrodynamics.

Freeman John Dyson (born 15 December 1923) is an American theoretical physicist and mathematician, of British origin, known for his work in quantum electrodynamics, solid-state physics, astronomy and nuclear engineering.

### Electromagnetic field

**electromagnetic fieldselectromagneticEMF**

Dirac described the quantization of the electromagnetic field as an ensemble of harmonic oscillators with the introduction of the concept of creation and annihilation operators of particles.

This quantum picture of the electromagnetic field (which treats it as analogous to harmonic oscillators) has proven very successful, giving rise to quantum electrodynamics, a quantum field theory describing the interaction of electromagnetic radiation with charged matter.

### Shin'ichirō Tomonaga

**Sin-Itiro TomonagaShin'ichiro TomonagaTomonaga**

Based on Bethe's intuition and fundamental papers on the subject by Shin'ichirō Tomonaga, Julian Schwinger, Richard Feynman and Freeman Dyson, it was finally possible to get fully covariant formulations that were finite at any order in a perturbation series of quantum electrodynamics.

Shinichiro Tomonaga, usually cited as Sin-Itiro Tomonaga in English, was a Japanese physicist, influential in the development of quantum electrodynamics, work for which he was jointly awarded the Nobel Prize in Physics in 1965 along with Richard Feynman and Julian Schwinger.

### Julian Schwinger

**SchwingerJulian S. SchwingerJ. Schwinger**

Based on Bethe's intuition and fundamental papers on the subject by Shin'ichirō Tomonaga, Julian Schwinger, Richard Feynman and Freeman Dyson, it was finally possible to get fully covariant formulations that were finite at any order in a perturbation series of quantum electrodynamics. Building on the pioneering work of Schwinger, Gerald Guralnik, Dick Hagen, and Tom Kibble, Peter Higgs, Jeffrey Goldstone, and others, Sheldon Lee Glashow, Steven Weinberg and Abdus Salam independently showed how the weak nuclear force and quantum electrodynamics could be merged into a single electroweak force.

He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order.

### Spontaneous emission

**spontaneousemissionspontaneously emit**

The first formulation of a quantum theory describing radiation and matter interaction is attributed to British scientist Paul Dirac, who (during the 1920s) was able to compute the coefficient of spontaneous emission of an atom.

The first person to derive the rate of spontaneous emission accurately from first principles was Dirac in his quantum theory of radiation, the precursor to the theory which he later coined quantum electrodynamics.

### Renormalization

**renormalizablerenormalisationrenormalized**

This procedure was named renormalization.

Renormalization was first developed in quantum electrodynamics (QED) to make sense of infinite integrals in perturbation theory.

### Special relativity

**special theory of relativityrelativisticspecial**

In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved.

Special relativity can be combined with quantum mechanics to form relativistic quantum mechanics and quantum electrodynamics.

### Photon

**photonslight quantaincident photon**

QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.

The answer to this question occupied Albert Einstein for the rest of his life, and was solved in quantum electrodynamics and its successor, the Standard Model (see ' and ', below).

### Quantum mechanics

**quantum physicsquantum mechanicalquantum theory**

The first formulation of a quantum theory describing radiation and matter interaction is attributed to British scientist Paul Dirac, who (during the 1920s) was able to compute the coefficient of spontaneous emission of an atom. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved.

The first complete quantum field theory, quantum electrodynamics, provides a fully quantum description of the electromagnetic interaction.

### Quantum chromodynamics

**QCDQuantum Chromodynamics (QCD)quantum chromodynamic**

One such subsequent theory is quantum chromodynamics, which began in the early 1960s and attained its present form in the 1970s work by H. David Politzer, Sidney Coleman, David Gross and Frank Wilczek.

Gluons are the force carrier of the theory, like photons are for the electromagnetic force in quantum electrodynamics.

### J. Robert Oppenheimer

**Robert OppenheimerOppenheimerRobert J. Oppenheimer**

However, further studies by Felix Bloch with Arnold Nordsieck, and Victor Weisskopf, in 1937 and 1939, revealed that such computations were reliable only at a first order of perturbation theory, a problem already pointed out by Robert Oppenheimer.

Oppenheimer did important research in theoretical astronomy (especially as related to general relativity and nuclear theory), nuclear physics, spectroscopy, and quantum field theory, including its extension into quantum electrodynamics.

### Richard Feynman

**FeynmanRichard P. FeynmanRichard Phillips Feynman**

Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen. Based on Bethe's intuition and fundamental papers on the subject by Shin'ichirō Tomonaga, Julian Schwinger, Richard Feynman and Freeman Dyson, it was finally possible to get fully covariant formulations that were finite at any order in a perturbation series of quantum electrodynamics.

Richard Phillips Feynman, ForMemRS (May 11, 1918 – February 15, 1988) was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics for which he proposed the parton model.

### Victor Weisskopf

**Victor Frederick WeisskopfVictor F. WeisskopfViki Weisskopf**

However, further studies by Felix Bloch with Arnold Nordsieck, and Victor Weisskopf, in 1937 and 1939, revealed that such computations were reliable only at a first order of perturbation theory, a problem already pointed out by Robert Oppenheimer.

In the 1930s and 1940s, 'Viki', as everyone called him, made major contributions to the development of quantum theory, especially in the area of quantum electrodynamics.

### Weak interaction

**weak forceweakweak nuclear force**

Building on the pioneering work of Schwinger, Gerald Guralnik, Dick Hagen, and Tom Kibble, Peter Higgs, Jeffrey Goldstone, and others, Sheldon Lee Glashow, Steven Weinberg and Abdus Salam independently showed how the weak nuclear force and quantum electrodynamics could be merged into a single electroweak force.

In addition to this, QFD is related to quantum chromodynamics (QCD), which deals with the strong interaction, and quantum electrodynamics (QED), which deals with the electromagnetic force.

### Anomalous magnetic dipole moment

**anomalous magnetic momentanomalous magnetic moment of the electronanomalous magnetic moment of the muon**

Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen.

In quantum electrodynamics, the 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.