What is torsion in general relativity?

General Relativity with nonvanishing torsion has been investigated in the first order formalism of Poincare gauge field theory. In the presence of torsion, either side of the Einstein equation has the nonvanishing covariant divergence. This fact turned out to be self-consistent in the framework under consideration.

Is general relativity part of quantum physics?

Or put another way, general relativity would be forced to make peace with quantum physics, because the space in which physicists measure the effects of relativity would itself be divided into unbreakable quantum units. The theatre of reality in which gravity acts would take place on a quantum stage.

Why can’t quantum mechanics explain gravity?

One of the difficulties of formulating a quantum gravity theory is that quantum gravitational effects only appear at length scales near the Planck scale, around 10−35 meters, a scale far smaller, and hence only accessible with far higher energies, than those currently available in high energy particle accelerators.

Why did Einstein dislike quantum mechanics?

Einstein always believed that everything is certain, and we can calculate everything. That’s why he rejected quantum mechanics, due to its factor of uncertainty.

What is space time torsion?

In Einstein–Cartan theory, the torsion is now a variable in the principle of stationary action that is coupled to a curved spacetime formulation of spin (the spin tensor). That is: “torsion does not propagate”. Generalizations of the Einstein–Cartan action have been considered which allow for propagating torsion.

Is gravity a quantum field?

Of the universe’s four fundamental forces (gravity, electromagnetism, and the strong and weak nuclear forces), only gravity lacks the “quantum” description. As a result, no one knows for sure (although there are plenty of ideas) where gravitational fields come from or how individual particles act inside them.

Can gravity be both attractive and repulsive?

Both in the Newton theory of gravitation and in the General Theory of Relativity the gravitational force is exclusively attractive one. However, the quantization of gravity shows that the gravitational forces can also be repulsive [3].

Is gravity a wave or particle?

If your question is about the force of gravity in relation to rest mass, the intermediating mechanism is not a wave and not a particle. It is vector space and the velocity is instantaneously. If your question is in relation to mass (like Dark matter), gravitation has wave properties and is bound to the speed of light.

What is the role of torsion tensor in relativity?

The torsion tensor is a quantity in general relativity, and plays an important role in Einstein–Cartan theory. Spinor fields, in particular fermionic fields, are existing concepts from particle physics and quantum field theory .

How is quantum mechanics related to general relativity?

For physicists, this calls for an even deeper generalisation, which has been pre-emptively given the name ‘quantum gravity’. In her research, Dr Sanchez aims to realise such a theory, in which both quantum mechanics and general relativity are particular branches which are contained on their appropriate scales.

How is semi-classical gravity related to general relativity?

Known as ‘semi-classical’ gravity, this model acts as a useful bridge between the separated theories of quantum mechanics and general relativity, and a unified theory of quantum gravity. Because of this, Dr Sanchez uses it as a standard theory, which emerges from her own theories in particular situations.

Which is an example of a torsion field?

Description. For example, an electromagnetic wave with circular polarization or the stress tensor of a solid body under torsion stress can be described as torsion fields, although such usage is rare. The torsion tensor is a quantity in general relativity, and plays an important role in Einstein–Cartan theory.