SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 42: Poster III

Q 42.1: Poster

Wednesday, March 8, 2023, 16:30–19:00, Empore Lichthof

Fermionic coherent state path integral for ultrashort laser pulses and transformation to a field theory of coset matrices — •Bernhard Mieck — keine Institution

A coherent state path integral of anti-commuting fields is considered for a two-band, semiconductor-related solid which is driven by a ultrashort, classical laser field. We describe the generation of exciton quasi-particles from the driving laser field as anomalous pairings of the fundamental, fermionic fields. This gives rise to Hubbard-Stratonovich transformations from the quartic, fermionic interaction to various Gaussian terms of self-energy matrices; the latter self-energy matrices are solely coupled to bilinear terms of anomalous-doubled, anti-commuting fields which are subsequently removed by integration and which create the determinant with the one-particle operator and the prevailing self-energy. We accomplish path integrals of even-valued self-energy matrices with Euclidean integration measure where three cases of increasing complexity are classified (scalar self-energy variable, density-related self-energy matrix and also a self-energy including anomalous doubled terms). According to the driving, anomalous-doubled Hamiltonian part, we also specify the case of a SSB with hinge-fields which factorizes the total self-energy matrix by a coset decomposition into density-related, block diagonal self-energy matrices of a background functional and into coset matrices with off-diagonal block generators for the anomalous pairings of fermions. This allows to derive a classical field theory for the self-energy matrices of exciton quasi-particles by gradient expansions of the determinant.