This article discusses the 9 most common types of quantum field theories, including QED, QCD, electroweak theory, and quantum gravity.

# 7 Most Common Types of Quantum Field Theories

Quantum field theory (QFT) is a theoretical framework that combines quantum mechanics and special relativity to describe the behavior of subatomic particles. QFT can be applied to various fields, including particle physics, condensed matter physics, and cosmology. In this article, we will discuss the 7 most common types of quantum field theories.

## 1. Quantum Electrodynamics (QED)

Quantum electrodynamics is the quantum field theory that describes the behavior of electrons and photons, the particles that make up light. It is one of the most well-established theories in physics and has been extensively tested through experiments. QED also provides the theoretical basis for many modern technologies, including lasers and transistors.

## 2. Quantum Chromodynamics (QCD)

Quantum chromodynamics is the quantum field theory that describes the behavior of quarks and gluons, the particles that make up protons and neutrons. QCD is a fundamental theory of strong interactions, which are responsible for holding the nucleus of an atom together. QCD is also the basis for the study of high-energy physics, such as the behavior of particles in colliders.

## 3. Electroweak Theory

Electroweak theory is the quantum field theory that unifies the electromagnetic and weak interactions, two of the four fundamental forces of nature. It describes the behavior of particles such as electrons, neutrinos, and W and Z bosons. Electroweak theory was proposed in the 1970s and has been extensively tested through experiments, including the discovery of the Higgs boson in 2012.

## 4. Standard Model

The standard model is a quantum field theory that describes the behavior of all known particles and their interactions. It includes quantum electrodynamics, quantum chromodynamics, and electroweak theory. The standard model has been extensively tested through experiments and has accurately predicted the behavior of particles in a wide range of energies. However, it is not a complete theory and does not include gravity.

## 5. Supersymmetry

Supersymmetry is a hypothetical quantum field theory that proposes the existence of a new set of particles, called supersymmetric particles, that are partners to the known particles. Supersymmetry has the potential to explain several problems in particle physics, such as the hierarchy problem and the existence of dark matter. However, experimental evidence for