Spinor representation of rotation

In summary, the spinor representation for a rotation through an angle θ about an axis with direction vector n = (n_x, n_y, n_z) is given by g=exp{-i\frac{θ}{2}(n_x σ_x+n_yσ_y+n_zσ_z)}, where σ_{x, y, z} are Pauli matrices. This can also be represented as h=gxg^{-1}, where x represents a rotation in the vector space and g is a unitary matrix. However, this approach may not be mathematically rigorous and a better understanding can be gained through the use of Euler angles.
  • #1
raopeng
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Homework Statement


Show the spinor representation corresponding to the rotation through an angle θ about an axis with direction vector [itex]n = (n_x, n_y, n_z)[/itex] has the form: [itex]g=exp{-i\frac{θ}{2}(n_x σ_x+n_yσ_y+n_zσ_z)}, σ_{x, y, z} [/itex] are respectively Pauli matrix

Homework Equations


[itex]h=gxg^{-1}[/itex]

The Attempt at a Solution


Since pauli matrices span the matrix space, I try to interpret the three pauli matrices as basis in a vector space. Then following from the knowledge of Euler Angle the spinor representation is indeed of that form. But this approach seems nowhere close to mathematical rigour as it is in a geometry book.
 
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  • #2
I could also use the formula h=gxg^{-1} to start with, but I don't know where to begin as I am not familiar with this formula and what it means in physical terms.
 

Related to Spinor representation of rotation

1. What is a spinor representation of rotation?

A spinor representation of rotation is a mathematical tool used to describe the transformation of a vector or tensor under rotations in three-dimensional space. It is a complex vector space that represents the rotation group and is used in quantum mechanics and relativity.

2. How is a spinor different from a vector?

A spinor is a mathematical object that transforms differently than a vector under rotations. While a vector is a triple of numbers that transforms according to the rotation matrix, a spinor is a complex vector that transforms according to a different set of transformation rules. Spinors are used to describe the spin of particles, while vectors are used to describe their position and momentum.

3. What is the significance of spinor representation in physics?

Spinor representation is significant in physics as it is used to describe the spin of particles, which is an intrinsic property of particles that cannot be explained by classical mechanics. Spinor representation is essential in quantum mechanics and relativity, as it allows for a more accurate description of the behavior of particles.

4. How are spinors used in quantum mechanics?

In quantum mechanics, spinors are used to describe the spin of particles and the transformation of their states under rotations. Spinor fields are also used to represent fermions, which are particles with half-integer spin, such as electrons. The Dirac equation, which describes the behavior of fermions, uses spinor notation.

5. Can spinor representation be extended to higher dimensions?

Yes, spinor representation can be extended to higher dimensions, such as four-dimensional spacetime in relativity. In higher dimensions, spinors are used to represent the rotation group in higher dimensions and are essential in describing the behavior of particles in higher dimensional spaces. However, the mathematical properties of spinors may differ in higher dimensions compared to three dimensions.

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