242 citations · 2.4k across the 70 of their papers we have counts for
31 papers · 1 filter
An exact solution of the Dirac equation with CP violation
Tomislav Prokopec, Michael G. Schmidt, Jan Weenink
We consider Yukawa theory in which the fermion mass is induced by a Higgs like scalar. In our model the fermion mass exhibits a temporal dependence, which naturally occurs in the e…
The Gaussian entropy of fermionic systems
Tomislav Prokopec, Michael G. Schmidt, Jan Weenink
We consider the entropy and decoherence in fermionic quantum systems. By making a Gaussian Ansatz for the density operator of a collection of fermions we study statistical 2-point…
Decoherence in an Interacting Quantum Field Theory: Thermal Case
Jurjen F. Koksma, Tomislav Prokopec, Michael G. Schmidt
We study the decoherence of a renormalised quantum field theoretical system. We consider our novel correlator approach to decoherence where entropy is generated by neglecting obser…
Entropy and Correlators in Quantum Field Theory
Jurjen F. Koksma, Tomislav Prokopec, Michael G. Schmidt
It is well known that loss of information about a system, for some observer, leads to an increase in entropy as perceived by this observer. We use this to propose an alternative ap…
Decoherence in an Interacting Quantum Field Theory: The Vacuum Case
Jurjen F. Koksma, Tomislav Prokopec, Michael G. Schmidt
We apply the decoherence formalism to an interacting scalar field theory. In the spirit of the decoherence literature, we consider a "system field" and an "environment field" that…
F-term Uplift in Heterotic M-theory
Filipe Paccetti Correia, Michael G. Schmidt
We investigate the viability of F-term uplift in heterotic M-theory. With this aim we explore a natural ingredient of heterotic compactifications, namely vector bundle moduli. It i…
On the Yang-Mills two-loop effective action with wordline methods
Jan M. Pawlowski, Michael G. Schmidt, Jian-Hui Zhang
We derive the two-loop effective action for covariantly constant field strength of pure Yang-Mills theory in the presence of an infrared scale. The computation is done in the frame…
Moduli stabilization in heterotic M-theory
Filipe Paccetti Correia, Michael G. Schmidt
We reconsider the ingredients of moduli stabilization in heterotic M-theory. On this line we close a gap in the literature deriving the Kaehler potential dependence on vector bundl…
Effective Action in a General Chiral Model: Next to Leading Order Derivative Expansion in the Worldline Method
Andres Hernandez, Thomas Konstandin, Michael G. Schmidt
We present a formalism to determine the imaginary part of a general chiral model in the derivative expansion. Our formalism is based on the worldline path integral for the covarian…
Radion Stabilization In 5D SUGRA
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We present a detailed study of radion stabilization within 5D conformal SUGRA compactified on an orbifold. We use an effective 4D superfield description developed in…
4D Superfield Reduction of 5D Orbifold SUGRA and Heterotic M-theory
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We present a detailed study of the reduction to 4D of 5D supergravity compactified on the S^1/Z_2 orbifold. For this purpose we develop and employ a recently proposed N=1 conformal…
Gauge and Modulus Inflation from 5D Orbifold SUGRA
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We study the inflationary scenarios driven by a Wilson line field - the fifth component of a 5D gauge field and corresponding modulus field, within S^1/Z_2 orbifold supergravity (S…
The Radion in 5D Conformal SUGRA: Superspace Action
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We shortly review our new superfield formalism in the framework of Fujita, Kugo, Ohashi 5D conformal supergravity, in particular with an orbifold. The radion of the fifth…
Worldlines on Orbifolds and the Fayet-Iliopoulos Term
Felix Bruemmer, Michael G. Schmidt, Zurab Tavartkiladze
We adapt ``string-inspired'' worldline techniques to one-loop calculations on orbifolds, in particular on the orbifold. Our method also allows for the treatment of brane-…
(BPS) Fayet-Iliopoulos Terms in 5D Orbifold SUGRA
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We discuss Fayet-Iliopoulos terms in the context of five-dimensional supergravity compactified on an orbifold. For this purpose we use our superfield formulation of the off-shell 5…
Superfield Approach to 5D Conformal SUGRA and the Radion
Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
We propose that the radion chiral supermultiplet of five dimensional compactified supergravity is obtained by reduction of the graviphoton gauge multiplet to N=1 superfields in the…
Resummed effective action in the world-line formalism
Thomas Auer, Michael G. Schmidt, Claus Zahlten
Using the world-line method we resum the scalar one-loop effective action. This is based on an exact expression for the one-loop action obtained for a background potential and a Ta…
Q-balls: Some Analytical Results
F. Paccetti Correia, M. G. Schmidt
Motivated by the renewed interest in the role of Q-balls in cosmological evolution, we present a discussion of the main properties of Q-balls, including some new results.
Two-loop Feynman Diagrams in Yang-Mills Theory from Bosonic String Amplitudes
Boris Kors, Michael G. Schmidt
We present intermediate results of an ongoing investigation which attempts a generalization of the well known one-loop Bern Kosower rules of Yang-Mills theory to higher loop orders…
Two-loop Yang-Mills theory in the world-line formalism and an Euler-Heisenberg type action
Haru-Tada Sato, Michael G. Schmidt, Claus Zahlten
Within the framework of the world-line formalism we write down in detail a two-loop Euler-Heisenberg type action for gluon loops in Yang-Mills theory and discuss its divergence str…
World-line approach to the Bern-Kosower formalism in two-loop Yang-Mills theory
Haru-Tada Sato, Michael G. Schmidt
Based on the world-line formalism with a sewing method, we derive the Yang-Mills effective action in a form useful to generate the Bern-Kosower-type master formulae for gluon scatt…
World Line Path Integrals as a Calculational Tool in Quantum Field Theory
Michael G. Schmidt, Christian Schubert
We report on the status of the string-inspired world line path integral formalism, a recently developed powerful tool for the reorganisation of standard perturbative amplitudes in…
Exact Combinatorics of Bern-Kosower-type Amplitudes for Two-Loop Theory
Haru-Tada Sato, Michael G. Schmidt
Counting the contribution rate of a world-line formula to Feynman diagrams in theory, we explain the idea how to determine precise combinatorics of Bern-Kosower-like amplitud…
The Higher Derivative Expansion of the Effective Action by the String Inspired Method. Part II
D. Fliegner, P. Haberl, M. G. Schmidt +1
We apply the string inspired worldline formalism to the calculation of the higher derivative expansion of one-loop effective actions in non-Abelian gauge theory. For this purpose,…