A way out has been given by Ludvig Faddeev and Victor Popov with the introduction of a ghost field (see Faddeev–Popov ghost) that has the property of being unphysical since, although it agrees with Fermi–Dirac statistics, it is a complex scalar field, which violates the spin-statistics theorem.
Ludvig Holberg | Ludvig Nobel | Carl Ludvig Engel | Ludvig Holstein-Ledreborg | Faddeev–Popov ghost | Sven Ludvig Lovén | Ludvig Verner Helms | Ludvig Lorenz | Ludvig Kornerup | Ludvig Holstein-Holsteinborg | Ludvig Faddeev | Johan Ludvig Runeberg | Johan Ludvig Heiberg |