TY - JOUR
T1 - Representing multiqubit unitary evolutions via Stokes tensors
JF - Phys. Rev. A 70 (2004) 032331
Y1 - 2004
A1 - Claudio Altafini
AB - For the Stokes tensor parametrization of a multiqubit density operator, we provide an explicit formulation of the corresponding unitary dynamics at the infinitesimal level. The main advantage of this formalism (clearly reminiscent of the ideas of ``coherences\\\'\\\' and ``coupling Hamiltonians\\\'\\\' of spin systems) is that the pattern of correlation between qubits and the pattern of infinitesimal correlation are highlighted simultaneously and can be used constructively for qubit manipulation. For example, it allows to compute explicitly a Rodrigues\\\' formula for the one-parameter orbits of nonlocal Hamiltonians. The result is easily generalizable to orbits of Cartan subalgebras and allows to express the Cartan decomposition of unitary propagators as a linear action directly in terms of the infinitesimal generators.
UR - http://hdl.handle.net/1963/2307
U1 - 1709
U2 - Mathematics
U3 - Functional Analysis and Applications
ER -