The loop expansion for the effective potential in theP(?)2 quantum field theory

1985 ◽  
Vol 102 (3) ◽  
pp. 425-462 ◽  
Author(s):  
Gordon Slade
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Effective Potential ◽  
Quantum Field ◽  
Loop Expansion

MESON-DIQUARK LOOP EXPANSION

1993 ◽  
Vol 08 (02) ◽  
pp. 277-300 ◽  
Author(s):  
M. LUTZ ◽  
J. PRASCHIFKA
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Effective Action ◽  
Degrees Of Freedom ◽  
Auxiliary Field ◽  
Quantum Field ◽  
Field Approach ◽  
Loop Expansion ◽  
Quark Models

We consider a general (nonlocal) four-fermion quantum field theory and show how the Cornwall-Jackiw-Tomboulis effective action can be systematically expanded in the number, η, of composite, bose loops. This is achieved by the introduction of auxiliary, bilocal fields which describe fermion-fermion and fermion-antifermion correlations. The η expansion can be understood as a generalization of the [Formula: see text] expansion and is of particular interest in quark models, for example, where the bilocal fields can be identified with meson and diquark degrees of freedom. Comparison with the usual loop (ħ) expansion reveals some unusual characteristics of the η expansion and throws light on recent studies of diquark degrees of freedom in which the auxiliary field approach is used.

scholarly journals Fixing the non-relativistic expansion of the 1PM potential

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Gianluca Grignani ◽  
Troels Harmark ◽  
Marta Orselli ◽  
Andrea Placidi
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scattering Amplitudes ◽  
Canonical Transformation ◽  
Effective Potential ◽  
Scattering Amplitude ◽  
Quantum Field ◽  
First Order ◽  
Scalar Matter ◽  
Frame Dependence

Abstract We obtain a first order post-Minkowskian two-body effective potential whose post-Newtonian expansion directly reproduces the Einstein-Infeld-Hoffmann potential. Post-Minkowskian potentials can be extracted from on-shell scattering amplitudes in a quantum field theory of scalar matter coupled to gravity. Previously, such potentials did not reproduce the Einstein-Infeld-Hoffmann potential without employing a suitable canonical transformation. In this work, we resolve this issue by obtaining a new expression for the first-order post-Minkowskian potential. This is accomplished by exploiting the reference frame dependence that arises in the scattering amplitude computation. Finally, as a check on our result, we demonstrate that our new potential gives the correct scattering angle.

Construction of an effective potential in quantum field theory at finite temperature

1976 ◽  
Vol 26 (2) ◽  
pp. 112-114 ◽  
Author(s):  
N. V. Krasnikov ◽  
V. A. Matveev ◽  
A. N. Tavkhelidze ◽  
K. G. Chetyrkin
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Effective Potential ◽  
Finite Temperature ◽  
Quantum Field

THE UNCERTAINTY OF THE GAUSSIAN EFFECTIVE POTENTIAL

1988 ◽  
Vol 03 (09) ◽  
pp. 2143-2163 ◽  
Author(s):  
R. MUÑOZ-TAPIA ◽  
J. TARON ◽  
R. TARRACH
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Quantum Mechanics ◽  
Effective Potential ◽  
Anharmonic Oscillator ◽  
Liouville Theory ◽  
Quantum Field ◽  
First Case ◽  
Gaussian Effective Potential

An uncertainty is introduced for the Gaussian Effective Potential. The definition is quite straightforward for quantum mechanics but fairly subtle for quantum field theory. The uncertainty provides a good estimation of the error in the first case, but renormalization seems to spoil its usefulness in the second case. The examples considered are the anharmonic oscillator, λϕ4 in 3+1 dimensions and the Liouville theory in 1+1 dimensions.

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