Understanding Spinors: Rank-1/2 Tensors & Square Roots of Vectors

  • Thread starter scope
  • Start date
  • Tags
    Spinors
In summary, a spinor can be considered a rank-1/2 tensor or the square root of a vector. This is because a scalar remains unchanged under rotations, a vector changes once, a rank-2 tensor changes twice, a rank-3 tensor changes three times, and a spinor changes 1/2 time. In 4D, a scalar has 1 component, a vector has 4 components, a rank-2 tensor has 16 components, and a spinor has 2 components. This means that two complex components are equivalent to four real components. Additionally, a rank-2 tensor is transformed by multiplying it 2 times by the coordinate transformations when changing coordinates, which is the definition of a tensor in
  • #1
scope
61
0
hi,

can se say loosely that a spinor is a rank-1/2 tensor or the square root of a vector, since a scalar does not change under rotations, a vector changes one time, a rank 2-tensor two times, a rank 3 tensor 3 times, and a spinor 1/2 time.
also a scalar in 4d has 1 component, a vector 4 components, a rank-2 tensor 16 components, and a spin 2 components.

does that make sense?
 
Physics news on Phys.org
  • #2
scope said:
and a spin 2 components.

Two complex components = four real components.

rank 2-tensor two times...

?
 
  • #3
arkajad said:
Two complex components = four real components.



?

yes a rank-2 tensor when we change coordinates, is transformed by multiplying it 2 times by the coordinate transformations, that is the definition of a tensor in physics.

for example if this transformation is a 2pi rotation, the graviton as a tensorial particle is rotated 2 times by 2pi.
 
  • #4
Do you want to say that after rotation by pi any rank2 tensor does not change?
 

FAQ: Understanding Spinors: Rank-1/2 Tensors & Square Roots of Vectors

What are spinors?

Spinors are mathematical objects used in physics to represent the intrinsic angular momentum (spin) of particles. They are represented as rank-1/2 tensors, which are a combination of vectors and square roots of vectors.

How are spinors different from other tensors?

Spinors are distinct from other tensors in that they transform differently under rotations. While other tensors transform as a product of the rotation matrix and itself, spinors transform as a product of the square root of the rotation matrix and itself.

What is the significance of rank-1/2 tensors in spinors?

The rank-1/2 tensor representation of spinors allows them to behave differently from other tensors under rotations, making them an essential tool in describing the spin of particles in quantum mechanics.

How are spinors used in physics?

Spinors are used in many areas of physics, including quantum mechanics, relativity, and particle physics. They are particularly useful in describing the spin of particles and their interactions with other particles.

Can spinors be visualized in three-dimensional space?

No, spinors cannot be visualized in three-dimensional space because they have complex components. However, they can be represented mathematically and used to make predictions about the behavior of particles in three-dimensional space.

Back
Top