Gravitational flux tubes

By studying multidimensional Kaluza–Klein theories, or gravity plus U(1) or SU(2) gauge fields it is shown that these theories possess similar flux tube solutions. The gauge field which fills the tube geometry of these solutions leads to a comparison with the flux tube structures in QCD. These solutions also carry a “magnetic” charge, Q, which for the SU(2) Einstein–Yang–Mills (EYM) system exhibits a dual relationship with the Yang–Mills gauge coupling, g, (Q=1/g). As Q→0 or Q→∞, g→∞ or g→0 respectively. Thus within this classical EYM field theory we find solutions which have features – flux tubes, magnetic charges, large value of the gauge coupling – that are similar to the key ingredients of confinement in QCD.