@article{Schmidt2007,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Fourth order gravity : equations, history, and application to cosmology},
  year      = {2007},
  abstract  = {The field equations following from a Lagrangian L(R) will be deduced and solved for special cases. If L is a non-linear function of the curvature scalar, then these equations are of fourth order in the metric. In the introduction we present the history of these equations beginning with the paper of H. Weyl from 1918, who first discussed them as alternative to Einstein's theory. In the third part, we give details about the cosmic no hair theorem, i.e., the details how within fourth order gravity with L= R + R^2 the inflationary phase of cosmic evolution turns out to be a transient attractor. Finally, the Bicknell theorem, i.e. the conformal relation from fourth order gravity to scalar- tensor theory, will be shortly presented.},
  language  = {en}
}
@article{Schmidt2005,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Einsteins Arbeiten in Bezug auf die moderne Kosmologie : de Sitters L{\"o}sung der Einsteinschen Feldgleichung mit positivem kosmologischen Glied als Geometrie des inflationaeren Weltmodells},
  year      = {2005},
  abstract  = {Die Arbeit von Albert Einstein von 1918 zu Willem De Sitters Loesung der Einsteinschen Feldgleichung wird unter heutigem Gesichtspunkt kommentiert. Dazu wird zunaechst die Geometrie der De Sitterschen Raum-Zeit beschrieben, sowie ihre Bedeutung fuer das inflationaere Weltmodell erlaeutert.},
  language  = {de}
}
@article{Schmidt2005,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Schwarzschild and Synge once again},
  issn      = {0001-7701},
  year      = {2005},
  abstract  = {We complete the historical overview about the geometry of a Schwarzschild black hole at its horizon by emphasizing the contribution made by Synge in [6] to its clarification},
  language  = {en}
}
@article{Schmidt2005,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Untitled},
  year      = {2005},
  language  = {de}
}
@article{Schmidt2003,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {The square of the Weyl tensor can be negative},
  year      = {2003},
  abstract  = {We show that the square of the Weyl tensor can be negative by giving an example},
  language  = {en}
}
@article{CanforaSchmidt2003,
  author    = {Canfora, Fabrizio and Schmidt, Hans-J{\"u}rgen},
  title     = {Vacuum solutions which cannot be written in diagonal form},
  year      = {2003},
  abstract  = {A vacuum solution of the Einstein gravitational field equation is shown to follow from a general ansatz but fails to follow from it if the symmetric matrix in it is assumed to be in diagonal form.},
  language  = {en}
}
@article{KleinertSchmidt2002,
  author    = {Kleinert, Hagen and Schmidt, Hans-J{\"u}rgen},
  title     = {Cosmology with curvature-saturated gravitational lagrangian},
  year      = {2002},
  abstract  = {We argue that the Lagrangian L(R) for gravity should remain bounded at large curvature, and interpolate between the weak-field tested Einstein-Hilbert Lagrangian and a pure cosmological constant for large R with the curvature- saturated ansatz. The curvature-dependent effective gravitational constant tends to infinity for large R, in contrast to most other approaches where it tends to 0. The theory possesses neither ghosts nor tachyons, but it fails to be linearization stable. On the technical side we show that two different conformal transformations make L asymptotically equivalent to the Gurovich-ansatz on the one hand, and to Einstein's theory with a minimally coupled scalar field with self-interaction on the other.},
  language  = {en}
}
@article{DzhunushalievRurenkoSchmidt2002,
  author    = {Dzhunushaliev, Vladimir and Rurenko, O. and Schmidt, Hans-J{\"u}rgen},
  title     = {Spherically symmetric solutions in multidimensional gravity with the SU(2) gauge group as the extra dimensions},
  year      = {2002},
  language  = {en}
}
@article{GorbatenkoPushkinSchmidt2002,
  author    = {Gorbatenko, M. V. and Pushkin, A. V. and Schmidt, Hans-J{\"u}rgen},
  title     = {On a relation between the Bach equation and the equation of geometrodynamics},
  year      = {2002},
  abstract  = {The Bach equation and the equation of geometrodynamics are based on two quite different physical motivations, but in both approaches, the conformal properties of gravitation plays the key role. In this paper we present an analysis of the relation between these two equations and show that the solutions of the equation of geometrodynamics are of a more general nature. We show the following non-trivial result: there exists a conformally invariant Lagrangian, whose field equation generalizes the Bach equation and has as solutions those Ricci tensors which are solutions to the equation of geometrodynamics.},
  language  = {en}
}
@article{Schmidt1997,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {A new duality transformation for fouth-order gravity},
  year      = {1997},
  language  = {en}
}