Quasi-particle states in a semiconductor

Here we want to summarj e our recent calculations of singleparticle excitations in Si, which aim at a similar quantitative 

The Time-Dependent Screened Hartree-Fock (TDSHF) Approximation 

We employ the time-dependent screened HF approximation (TDSHF), which replaces the bare Coulomb interaction v in the HF self- energy (Fig.l) by a dynamically screened interaction (eq.(2.4)) v  

The corresponding vertex function T derives from the integral equation (2.5) with the kernel 

This irreducible e-h interaction, via a Ward identity, also determines the particle-hole interaction in the Bethe-Salpeter equation (2.7) for the two-particle propagator. Ideally, we should 

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