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The higher derivative expansion of the one-loop effective action for an external scalar potential is calculated to order O(T 7), using the string-inspired Bern-Kosower method in the first quantized path integral formulation. Comparisons are made with standard heat kernel calculations and with the corresponding Feynman diagrammatic calculation in order to… (More)

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 scattering amplitudes at the two-loop level. It is shown that four-gluon (Φ 4 type sewing) contributions can be encapsulated in the action with three-gluon (Φ 3 type) vertices only,… (More)

Prior observations of phage-host systems in vitro have led to the conclusion that susceptible host cell populations must reach a critical density before phage replication can occur. Such a replication threshold density would have broad implications for the therapeutic use of phage. In this report, we demonstrate experimentally that no such replication… (More)

We investigate the usefulness of the \string-inspired technique" for gauge theory calculations in a constant external eld background. Our approach is based on Strassler's worldline path integral approach to the Bern-Kosower formalism, and on the construction of worldline (super{) Green's functions incorporating external elds as well as internal propagators.… (More)

- Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
- 2004

We propose that the radion chiral supermultiplet of five dimensional compactified super-gravity is obtained by reduction of the graviphoton gauge multiplet to N = 1 superfields in the off shell 5D superconformal gravity formalism of Fujita, Kugo and Ohashi. We present a superfield Lagrangian of Chern-Simons type (similar to global SUSY), which reproduces… (More)

- Kimmo Kainulainen, Tomislav Prokopec, Michael G. Schmidt, Steffen Weinstock
- 2001

We perform a systematic gradient expansion on kinetic equations and derive the CP-violating semiclassical force for fermions propagating in presence of a CP-violating wall at a first order electroweak phase transition. The force appears at order ¯ h in the flow term of kinetic equation and agrees with the semiclassical force used for baryogenesis… (More)

Strassler's formulation of the string-derived Bern-Kosower formalism is reconsidered with particular emphasis on effective actions and form factors. Two-and three point form factors in the nonabelian effective action are calculated and compared with those obtained in the heat kernel approach of Barvinsky, Vilkovisky et al. We discuss the Fock-Schwinger… (More)

- Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze
- 2006

We present a detailed study of the reduction to 4D of 5D supergravity compactified on the S 1 / 2 orbifold. For this purpose we develop and employ a recently proposed N = 1 conformal superfield description of the 5D supergravity couplings to abelian vector and hypermultiplets. In particular, we obtain a unique relation of the " radion " to chiral… (More)

- Kimmo Kainulainen, Tomislav Prokopec, Michael G. Schmidt, Steffen Weinstock
- 2001

We consider the dynamics of fermions with a spatially varying mass which couple to bosons through a Yukawa interaction term and perform a consistent weak coupling truncation of the relevant kinetic equations. We then use a gradient expansion and derive the CP-violating source in the collision term for fermions which appears at first order in gradients. The… (More)

- Boris Körs, Michael G. Schmidt
- 1998

Using the Worldline formalism of QED we compute the two-loop effective action induced by a charged scalar, respectively spinor particle in a general constant electromagnetic field.