5 research outputs found
On non-Adiabatic Holonomoic Quantum Computer
Non-adiabatic non-Abelian geometric phase of spin-3/2 system in the rotating
magnetic field is considered. Explicit expression for the corresponding
effective non-Abelian gauge potential is obtained. This formula can be used for
construction of quantum gates in quantum computations.Comment: 6 page
Massive Electrodynamics and the Magnetic Monopoles
We investigate in detail the problem of constructing magnetic monopole
solutions within the finite-range electrodynamics (i.e., electrodynamics with
non-zero photon mass, which is the simplest extension of the standard theory;
it is fully compatible with the experiment). We first analyze the classical
electrodynamics with the additional terms describing the photon mass and the
magnetic charge; then we look for a solution analogous to the Dirac monopole
solution. Next, we plug the found solution into the Schr\"{o}dinger equation
describing the interaction between the the magnetic charge and the electron.
After that, we try to derive the Dirac quantization condition for our case.
Since gauge invariance is lost in massive electrodynamics, we use the method of
angular momentum algebra. Under rather general assumptions we prove the theorem
that the construction of such an algebra is not possible and therefore the
quantization condition cannot be derived. This points to the conclusion that
the Dirac monopole and the finite photon mass cannot coexist within one and the
same theory. Some physical consequences of this conclusion are considered. The
case of t'Hooft-Polyakov monopole is touched upon briefly.Comment: 24 pages, revtex, 1 figure appended as a PostScript fil