In this work we present an extended version of the Friedrichs Model, which includes fermion-boson couplings. The set of fermion bound states is coupled to a boson field with discrete and continuous components. As a result of the coupling some of the fermion states may become resonant states. This feature suggests the existence of a formal link between the occurrence of Gamow Resonant States in ...

and Applied Analysis 3 for all f ∈ C∞ 0 Ω . Since Aμ A μI is positive for sufficiently large μ it has a positive self-adjoint Friedrichs extension Aμ F such that D (( Aμ ) F ) ⊂ ◦ W m 2 Ω . 1.9 We define the Friedrichs extension of A Aμ − μI to be AF Aμ F − μI such that D AF ⊂ ◦ W m 2 Ω . 1.10 The domain of AF is given by D AF { f ∈ ◦ W m 2 Ω | Af ∈ L2 Ω } . 1.11 It is also well known that this...

This paper proposes Friedrichs learning as a novel deep methodology that can learn the weak solutions of PDEs via minmax formulation, which transforms PDE problem into minimax optimization to identify solutions. The name "Friedrichs learning" is for highlighting close relationship between our strategy and theory on symmetric systems PDEs. solution test function in formulation are parameterized ...

Friedemann Scheck, Interessen und Konflikte. Eine Untersuchung zur politischen Praxis im frühneuzeitlichen Württemberg am Beispiel von Herzog Friedrichs Weberwerk (1598 – 1608) (Schriften südwestdeutschen Landeskunde, Bd. 81). Ostfildern: Thorbecke 2020. 292 S. ISBN 978-3-7995-5281-3. € 39,–

We show that the Friedrichs–Lee model, which describes one-excitation sector of a two-level atom interacting with structured boson field, can be generalized to singular atom–field couplings. provide characterization its spectrum and resonances discuss inverse spectral problem.