We theoretically study the ground-state properties and condensations of exciton-like Cooper pairs biexciton-like quartets in an electron-hole system. Applying variational approach associated based on quartet Bardeen-Cooper-Schrieffer (BCS) model to four-component fermionic system consisting spin-1/2 electrons holes, we show how correlations appear equation state at thermodynamic limit. The four...

Recent theoretical studies have suggested that the suddenly recoiled atom struck by dark matter (DM) particle is much more likely to excite or lose its electrons than expected. Such Migdal effect provides a new avenue for exploring sub-GeV DM particles. There been various attempts describe in liquids and semiconductor targets. In this paper we incorporate treatment of bremsstrahlung process ele...