Thermal contribution of unstable states

Lo, Pok Man (Aff1, 0000 0001 1010 5103, grid.8505.8, Institute of Theoretical Physics, University of Wroclaw, 50-204, Wrocław, Poland) ; Giacosa, Francesco (Aff2, 0000 0001 2292 9126, grid.411821.f, Institute of Physics, Jan-Kochanowski University, 25-406, Kielce, Poland)

13 April 2019

Abstract: Within the framework of the Lee model, we analyze in detail the difference between the energy derivative of the phase shift and the standard spectral function of the unstable state. The fact that the model is exactly solvable allows us to demonstrate the construction of these observables from various exact Green functions. The connection to a formula due to Krein, Friedal, and Lloyd is also examined. We also directly demonstrate how the derivative of the phase shift correctly identifies the relevant interaction contributions for consistently including an unstable state in describing the thermodynamics.


Published in: EPJC 79 (2019) 336 DOI: 10.1140/epjc/s10052-019-6844-y
License: CC-BY-3.0



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