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Updated: Aug 20, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
CP violation from five-dimensional QED
Bohdan Grzadkowski1, José Wudka
1Institute of Theoretical Physics, Warsaw University Hoza 69, PL-00-681 Warsaw, Poland. bohdan.grazadkowski@fuw.edu.pl
Abstract:
It is shown that QED in (1 + 4)-dimensional space-time, with the fifth dimension compactified on a circle, is, in general, a CP violating theory. Depending on the fermionic boundary conditions, CP violation may be either explicit (through the Scherk-Schwarz mechanism) or spontaneous (via the Hosotani mechanism). The fifth component of the gauge field acquires (at the one-loop level) a nonzero vacuum expectation value which, in the presence of two fermionic fields, leads to spontaneous CP violation when the boundary conditions are CP symmetric. Phenomenological consequences are illustrated by a calculation of the electric dipole moment for the fermionic zero modes.
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