Quasisecular Perturbative Method for Calculating Bound States in Quantum Field Theory

1972 ◽  
Vol 6 (10) ◽  
pp. 2773-2779 ◽  
Author(s):  
S. Ø. Aks ◽  
B. B. Varga
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Bound States ◽  
Quantum Field ◽  
Perturbative Method

scholarly journals Computational approach for calculating bound states in quantum field theory

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
Q. Z. Lv ◽  
S. Norris ◽  
R. Brennan ◽  
E. Stefanovich ◽  
Q. Su ◽  
...  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Bound States ◽  
Computational Approach ◽  
Quantum Field

THE PRINCIPLE OF MINIMAL SENSITIVITY APPLIED TO A NEW PERTURBATIVE SCHEME IN QUANTUM FIELD THEORY

1989 ◽  
Vol 04 (07) ◽  
pp. 1735-1746 ◽  
Author(s):  
H. F. JONES ◽  
M. MONOYIOS
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Dimensional Space ◽  
Exact Result ◽  
Field Theories ◽  
Quantum Field ◽  
One Dimensional ◽  
Perturbative Method ◽  
Improved Accuracy

A recently proposed perturbative method for solving a self-interacting scalar φ4 field theory consists of writing the interaction as gφ2(1+δ) and expanding in powers of δ. The method contains an ambiguity in so far as one could modify the interaction Lagrangian by a factor λ(1−δ). The truncated expansion depends on the unphysical parameter, whereas the exact result does not. We exploit this ambiguity by assigning to λ the value for which the truncated result is stationary, thus minimizing its sensitivity to λ. The technique is applied to field theories in zero-and one-dimensional space-times and gives improved accuracy as compared to fixed λ.

Quantum field theory of bound states II. Relativistic theory of resonance reactions

1953 ◽  
Vol 217 (1130) ◽  
pp. 390-408 ◽  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Integral Equation ◽  
Bound States ◽  
Relativistic Quantum ◽  
Nuclear Resonance ◽  
Quantum Field ◽  
Relativistic Quantum Field Theory ◽  
Level Width ◽  
Resonance Reactions

Relativistic quantum field theory is extended so that it can be used as a basis for a qualitative study of nuclear resonance reactions. The general resonance formulae are derived in a relativistic form, and the interference between neighbouring levels is investigated. It is assumed that resonance arises from the formation of a compound nucleus which subsequently disintegrates. The essential features of resonance and level width are, in the first instance, derived from a simple resonating model. This shows that, while resonance arises directly from the Feynman propagator in lowest approximation, the level widths come from considering an infinite series of Feynman-Dyson diagrams; these can be represented by an integral equation. In considering a general nuclear resonance reaction it is necessary to use compound propagators, which were introduced by the author in the first paper of this series. The general form of the compound propagator is obtained in stable approximation, and the integral equation is derived which allows for the possibility of disintegration. The solution of this equation leads to the relativistic formulae for a general resonance reaction.

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