Effective Lagrangian and Quantum Screening in Charged Condensate

TL;DR

This paper investigates the effective Lagrangian of a charged scalar condensate in a fermionic background, revealing strong screening effects due to phonon cancellations and quantum corrections, which imply efficient screening of impurities.

Contribution

It introduces an effective Lagrangian framework showing phonon-induced cancellations that enhance electric charge screening in charged condensates.

Findings

Strong screening of electric charges due to phonon effects.

Quantum corrections are suppressed by phonon subtraction.

Charged impurities are efficiently screened by the condensate.

Abstract

A condensate of charged scalars in a neutralizing background of fermions (e.g., condensed helium-4 nuclei in an electron background in white dwarf cores) is investigated further. We discuss an effective Lagrangian approach to this system and show that the strong screening of an electric charge found previously in arXiv:0806.3692 in a mean-field approximation, is a consequence of a cancellation due to a phonon. The resulting propagators contain terms that strongly modify their infrared behavior. Furthermore, we evaluate a one-loop fermion quantum correction to the screened potential, and find that it is also suppressed by the phonon subtraction. Therefore, charged impurities (e.g., hydrogen or helium-3 nuclei) will be screened efficiently by the condensate.