Note on "Lifetime Effects in Coupled Channel Problems"

1974 ◽  
Vol 52 (24) ◽  
pp. 2506-2508
Author(s):  
Koichi Nakamura

The simple field theoretical model of coupled channel problems proposed by Kamal and Kreuzer is solved in the Tamm-Dancoff approximation. Some comments are made on their method of inclusion of self energy effects in the unstable particle propagator.

1974 ◽  
Vol 52 (7) ◽  
pp. 608-617
Author(s):  
A. N. Kamal ◽  
H. J. Kreuzer

Lifetime effects of unstable particles in coupled channel problems are studied in a simple field theoretical model and in some nonrelativistic 2-channel models. The instability of higher channel particles is taken into account via self-energy effects. Resonance and cusp modifications are studied numerically in great detail.


1992 ◽  
Vol 395 ◽  
pp. 612 ◽  
Author(s):  
Jose V. Romero ◽  
J. Diaz Alonso ◽  
Jose M. Ibanez ◽  
Juan A. Miralles ◽  
Armando Perez

2005 ◽  
Vol 20 (15) ◽  
pp. 3495-3501 ◽  
Author(s):  
VAHAGN NAZARYAN ◽  
CARL E. CARLSON

In this talk we present a field theoretical model constructed in Minkowski [Formula: see text] superspace with a deformed supercoordinate algebra. Our study is motivated in part by recent results from super-string theory, which show that in a particular scenario in Euclidean superspace the spinor coordinates θ do not anticommute. Field theoretical consequences of this deformation were studied in a number of articles. We present a way to extend the discussion to Minkowski space, by assuming non-vanishing anticommutators for both θ, and [Formula: see text]. We give a consistent supercoordinate algebra, and a star product that is real and preserves the (anti)chirality of a product of (anti)chiral superfields. We also give the Wess-Zumino Lagrangian [Formula: see text] that gains only Lorentz-invariant corrections due to non(anti)commutativity within our model. The Lagrangian in Minkowski superspace is also always manifestly Hermitian.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dmitrii Nabok ◽  
Stefan Blügel ◽  
Christoph Friedrich

AbstractThis work combines two powerful self-energy techniques: the well-known GW method and a self-energy recently developed by us that describes renormalization effects caused by the scattering of electrons with magnons and Stoner excitations. This GT self-energy, which is fully k-dependent and contains infinitely many spin-flip ladder diagrams, was shown to have a profound impact on the electronic band structure of Fe, Co, and Ni. In the present work, we refine the method by combining GT with the GW self-energy. The resulting GWT spectral functions exhibit strong lifetime effects and emergent dispersion anomalies. They are in an overall better agreement with experimental spectra than those obtained with GW or GT alone, even showing partial improvements over local-spin-density approximation dynamical mean-field theory. The performed analysis provides a basis for applying the GWT technique to a wider class of magnetic materials.


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