arXiv:hep-lat/0305005·v1·High Energy Physics — Lattice
Theta-vacuum systems via real action simulations
V. Azcoiti🇪🇸 · G. Di Carlo🇮🇹 · A. Galante🇮🇹 · V. Laliena🇪🇸
Abstract
Inspired by the results of the Ising model within an imaginary external magnetic field, we introduce a transformation in quantum systems with a theta-vacuum term that amounts to a rescaling of z=cos(theta/2). Making use of this transformation we are able to determine the order parameter as a function of theta. The approach is successfully tested in models with both broken and unbroken CP symmetry at theta=pi.
Comments: 14 pages, 6 figures; To appear in Phys. Lett. B