A Gaussian fixed point is a fixed point

Fixed point (mathematics)

In mathematics, a fixed point of a function is a point that is mapped to itself by the function. A set of fixed points is sometimes called a fixed set...

 of the renormalization group flow which is noninteracting in the sense that it is described by a free field theory. The word Gaussian comes from the fact that the probability distribution is Gaussian at the Gaussian fixed point. This means that Gaussian fixed points are exactly solvable (trivially

Quantum triviality

In a quantum field theory, charge screening can restrict the value of the observable "renormalized" charge of a classical theory. Ifthe only allowed value of the renormalized charge is zero, the theory is said to be "trivial" or noninteracting...

 solvable in fact). Slight deviations from the Gaussian fixed point can be described by perturbation theory.

See also

• UV fixed point
  UV fixed point
  In a quantum field theory, one may calculate an effectiveor running coupling constant that defines thecoupling of the theory measured at a given momentum scale.One example of such a coupling constantis the electric charge...
  
  
• IR fixed point
• Quantum triviality
  Quantum triviality
  In a quantum field theory, charge screening can restrict the value of the observable "renormalized" charge of a classical theory. Ifthe only allowed value of the renormalized charge is zero, the theory is said to be "trivial" or noninteracting...