Unit quaternions and the Bloch sphere.

Autor: K B Wharton, D Koch
Předmět:
Zdroj: Journal of Physics A: Mathematical & Theoretical; 6/10/2015, Vol. 48 Issue 23, p1-1, 1p
Abstrakt: The spinor representation of spin-1/2 states can equally well be mapped to a single unit quaternion, yielding a new perspective despite the equivalent mathematics. This paper first demonstrates a useable map that allows Bloch-sphere rotations to be represented as quaternionic multiplications, simplifying the form of the dynamical equations. Left-multiplications generally correspond to non-unitary transformations, providing a simpler (essentially classical) analysis of time-reversal. But the quaternion viewpoint also reveals a surprisingly large broken symmetry, as well as a potential way to restore it, via a natural expansion of the state space that has parallels to second order fermions. This expansion to ‘second order qubits’ would imply either a larger gauge freedom or a natural space of hidden variables. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index