Bloch Electrons in Coherent Light: A New Type of Renormalization
In quantum theories which are concerned with the generation and propagation of light in crystals, one generally considers the physical picture in which the elementary single particle excitation is the Bloch electron, whose fundamental characteristics such as energy-momentum relations for different bands, band gaps, effective masses, charge and other coupling coefficients are not affected by the coherence of any field mode. Of course, under intense light excitations, many mobile carriers may be created in crystals, which in turn affect these fundamental parameters. However, such renormalizations are associated with incoherent processes involving nonequilibrium carrier populations and their relaxation via Coulomb scatterings, phonon emission and absorptions. For such processes, coherence of field modes is not relevant. What is relevant is their intensities. In the description of real transitions and nonequilibrium processes, one still uses to the basic Bloch electron picture.
KeywordsCoherent State Coherent Light Coherent Mode Excitonic Resonance Coulomb Coupling
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