In theoretical physics

Theoretical physics

Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...

, a graviscalar (also known as a radion) is a hypothetical particle that emerges as an excitation of the metric tensor

Metric tensor (general relativity)

In general relativity, the metric tensor is the fundamental object of study. It may loosely be thought of as a generalization of the gravitational field familiar from Newtonian gravitation...

 (i.e. gravitational field

Gravitational field

The gravitational field is a model used in physics to explain the existence of gravity. In its original concept, gravity was a force between point masses...

) but whose physical properties are virtually indistinguishable from a scalar

Scalar (physics)

In physics, a scalar is a simple physical quantity that is not changed by coordinate system rotations or translations , or by Lorentz transformations or space-time translations . This is in contrast to a vector...

 in four dimensions, as shown in Kaluza-Klein theory. The new scalar field

Scalar field

In mathematics and physics, a scalar field associates a scalar value to every point in a space. The scalar may either be a mathematical number, or a physical quantity. Scalar fields are required to be coordinate-independent, meaning that any two observers using the same units will agree on the...

  comes from a component of the metric tensor where the figure 5 labels an additional, fifth dimension. It can be thought of as a measure of the size of the extra dimension, with variations in the scalar field representing variations in the size of the extra dimensions.

In models with multiple extra dimensions, there exist several such particles.

In theories with extended supersymmetry, a graviphoton

Graviphoton

In theoretical physics, a graviphoton is a hypothetical particle which emerges as an excitation of the metric tensor in spacetime dimensions higher than four, as described in Kaluza-Klein theory....

 is usually a superpartner

Superpartner

In particle physics, a superpartner is a hypothetical elementary particle. Supersymmetry is one of the synergistic theories in current high-energy physics which predicts the existence of these "shadow" particles....

 of the graviton

Graviton

In physics, the graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory. If it exists, the graviton must be massless and must have a spin of 2...

 that behaves as a particle with spin

Spin (physics)

In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...

 1.

This concept it closely related to that of gauged Higgs models.

See also

• graviphoton
  Graviphoton
  In theoretical physics, a graviphoton is a hypothetical particle which emerges as an excitation of the metric tensor in spacetime dimensions higher than four, as described in Kaluza-Klein theory....
  
   (aka gravivector)
• dilaton
  Dilaton
  In particle physics, a dilaton is a hypothetical particle. It also appears in Kaluza-Klein theory's compactifications of extra dimensions when the volume of the compactified dimensions vary....
  
  
• Kaluza-Klein theory
• Randall-Sundrum model
  Randall-Sundrum model
  In physics, Randall–Sundrum models imagine that the real world is a higher-dimensional Universe described by warped geometry...
  
  s.
• Goldberger-Wise mechanism
  Goldberger-Wise mechanism
  In particle physics, the Goldberger–Wise mechanism is a popular mechanism that determines the size of the fifth dimension in Randall-Sundrum models. The mechanism uses a scalar field that propagates throughout the five-dimensional bulk...