Magnetically amplified light-shining-through-walls via virtual minicharged particles

Abstract

We show that magnetic fields have the potential to significantly enhance a recently proposed light-shining-through-walls scenario in quantum-field theories with photons coupling to minicharged particles. Suggesting a dedicated laboratory experiment, we demonstrate that this particular tunneling scenario could provide access to a parameter regime competitive with the currently best direct laboratory limits on minicharged fermions below the meV regime. With present day technology, such an experiment has the potential to even overcome the best model-independent cosmological bounds on minicharged fermions with masses below O(10 −4 )eV.

Laser-driven search of axion-like particles including vacuum polarization effects

“…To conclude this subsection we determine the phase velocity v ± = w ± (k k k)/|k k k| associated with each massless propagation mode, i.e., Eqs. (37) and (47). In this case we find…”

“…However, despite the push to detect these particles, the results provided by both kinds of experiments are far from proving that the photon oscillations into ALPs occur. Instead, upper bounds on the unknown parameter of ALPs, i.e., coupling constant g and mass m have been established, as well as for other weakly interacting particles including paraphotons [37,38,39,40,41] and mini-charged particles [42,43,44,45,46,47]. The main difficulty in these experiments stems from the projected lightness of the ALPs and the weakness of their coupling constants, hence the detection of their tiny observable effects represents a huge technical challenge.…”

Photon polarization tensor in a homogeneous magnetic or electric field

“…which imply that the transversal momentum is the dominant scale, i.e., momentum dominance. Let us emphasize that conditions (140) are also compatible with the limiting case m → 0, which is, e.g., of relevance in the search for minicharged particles [53][54][55]. Thus, in particular in the two regimes (134)-(137) and (139)-(140) the infinite series in Eq.…”

Critical Schwinger pair production. II. Universality in the deeply critical regime

“…In the strong-field limit, paramagnetism dominates which is reflected by a zero-mode of the squared Dirac operator for the lowest Landau level and a suitably oriented spin [43,62]. This mode is responsible for a variety of strong-field features that are unique to spinor QED [63][64][65][66][67][68]. In the present case, it is again the Pauli term dominating the strong field limit, even though the Minkowskian mode structure in the electric field is somewhat different from the magnetic case: e.g., there is no dependence on the orientation of the spin relative to the field, as the electron does not have a permanent electric dipole.…”