@article{SchmidtBaierBleyeretal.1994,
  author    = {Schmidt, Hans-J{\"u}rgen and Baier, Frank W. and Bleyer, Ulrich and Hubrig, Swetlana and Meister, Claudia-Veronika and Schilbach, Elena and Tiersch, Heinz},
  title     = {Zum Wissenschaftler-Integrationsprogramm},
  year      = {1994},
  language  = {de}
}
@article{DzhunushalievSchmidt2000,
  author    = {Dzhunushaliev, Vladimir and Schmidt, Hans-J{\"u}rgen},
  title     = {Wormholes and Flux Tubes in the 7D Gravity on the Principal Bundle with SU(2) Gauge Group as the Extra Dimensions},
  year      = {2000},
  language  = {en}
}
@article{Schmidt1994,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {WIP-Projekt "Kosmologie"},
  year      = {1994},
  language  = {de}
}
@book{Schmidt1994,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Why do all the curvature invariants of a gravitational wave vanish?},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1994, 03},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {7 Bl.},
  year      = {1994},
  language  = {en}
}
@article{Schmidt1996,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Why do all the curvature invariants of a gravitational wave vanish?},
  year      = {1996},
  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{Schmidt2005,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Untitled},
  year      = {2005},
  language  = {de}
}
@book{SchmidtMignemi1995,
  author    = {Schmidt, Hans-J{\"u}rgen and Mignemi, Salvatore},
  title     = {Two-dimensional higher-derivative gravity and conformal transformations},
  year      = {1995},
  language  = {en}
}
@article{SchmidtMignemi1995,
  author    = {Schmidt, Hans-J{\"u}rgen and Mignemi, Salvatore},
  title     = {Two-dimensional higher-derivative gravity and conformal transformations},
  year      = {1995},
  language  = {en}
}
@article{GurovichSchmidtTokareva2001,
  author    = {Gurovich, Viktor and Schmidt, Hans-J{\"u}rgen and Tokareva, Ira},
  title     = {Tunneling of the closed Friedmann Universe with generation of scalar waves},
  year      = {2001},
  abstract  = {The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler-DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is shown that during tunneling the amplitudes of short waves of a scalar field can increase catastrophically promptly if their influence to the metric is not taken into account. This effect is similar to the Rubakov-effect of catastrophic particle creation calculated already in 1984. In our approach to the problem it is possible to consider a self- consistent dynamics of the expansion of the Universe and amplification of short waves. It results in a decrease of the barrier and interruption of amplification of waves, and we get an exit of the wave function from the quantum to the classically available region.},
  language  = {en}
}
@book{SchmidtKluske1995,
  author    = {Schmidt, Hans-J{\"u}rgen and Kluske, Sabine},
  title     = {Towards a no hair theorem for higher order gravit},
  year      = {1995},
  language  = {en}
}
@article{KluskeSchmidt1996,
  author    = {Kluske, Sabine and Schmidt, Hans-J{\"u}rgen},
  title     = {Towards a cosmic no hair theorem for higher-order gravity},
  year      = {1996},
  language  = {en}
}
@article{Schmidt2000,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {Topologische Aspekte in der Kosmologie},
  year      = {2000},
  language  = {de}
}
@article{Schmidt2013,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {The tetralogy of Birkhoff theorems},
  series = {General relativity and gravitation},
  volume    = {45},
  journal   = {General relativity and gravitation},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {0001-7701},
  doi       = {10.1007/s10714-012-1478-5},
  pages     = {395 -- 410},
  year      = {2013},
  abstract  = {We classify the existent Birkhoff-type theorems into four classes: first, in field theory, the theorem states the absence of helicity 0- and spin 0-parts of the gravitational field. Second, in relativistic astrophysics, it is the statement that the gravitational far-field of a spherically symmetric star carries, apart from its mass, no information about the star; therefore, a radially oscillating star has a static gravitational far-field. Third, in mathematical physics, Birkhoff's theorem reads: up to singular exceptions of measure zero, the spherically symmetric solutions of Einstein's vacuum field equation with can be expressed by the Schwarzschild metric; for , it is the Schwarzschild-de Sitter metric instead. Fourth, in differential geometry, any statement of the type: every member of a family of pseudo-Riemannian space-times has more isometries than expected from the original metric ansatz, carries the name Birkhoff-type theorem. Within the fourth of these classes we present some new results with further values of dimension and signature of the related spaces; including them are some counterexamples: families of space-times where no Birkhoff-type theorem is valid. These counterexamples further confirm the conjecture, that the Birkhoff-type theorems have their origin in the property, that the two eigenvalues of the Ricci tensor of 2-D pseudo-Riemannian spaces always coincide, a property not having an analogy in higher dimensions. Hence, Birkhoff-type theorems exist only for those physical situations which are reducible to 2-D.},
  language  = {en}
}
@article{Schmidt2013,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {The tetralogy of Birkhoff theorems},
  issn      = {0001-7701},
  year      = {2013},
  abstract  = {We classify the existent Birkhoff-type theorems into four classes: First, in field theory, the theorem states the absence of helicity 0- and spin 0-parts of the gravitational field. Second, in relativistic astrophysics, it is the statement that the gravitational far-field of a spherically symmetric star carries, apart from its mass, no information about the star; therefore, a radially oscillating star has a static gravitational far-field. Third, in mathematical physics, Birkhoff's theorem reads: up to singular exceptions of measure zero, the spherically symmetric solutions of Einstein's vacuum field equation with Lambda = 0 can be expressed by the Schwarzschild metric; for Lambda unequal 0, it is the Schwarzschild-de Sitter metric instead. Fourth, in differential geometry, any statement of the type: every member of a family of pseudo-Riemannian space-times has more isometries than expected from the original metric ansatz, carries the name Birkhoff-type theorem. Within the fourth of these classes we present some new results with further values of dimension and signature of the related spaces; including them are some counterexamples: families of space-times where no Birkhoff-type theorem is valid. These counterexamples further confirm the conjecture, that the Birkhoff-type theorems have their origin in the property, that the two eigenvalues of the Ricci tensor of two- dimensional pseudo-Riemannian spaces always coincide, a property not having an analogy in higher dimensions. Hence, Birkhoff-type theorems exist only for those physical situations which are reducible to two dimensions.},
  language  = {en}
}
@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{SchmidtRainer1995,
  author    = {Schmidt, Hans-J{\"u}rgen and Rainer, Martin},
  title     = {The natural classification of real lie algebras},
  year      = {1995},
  language  = {en}
}
@book{BattagliaMayerSchmidt1993,
  author    = {Battaglia Mayer, Alexandra and Schmidt, Hans-J{\"u}rgen},
  title     = {The de Sitter space-time as attractor solution in eighth order gravity},
  series = {Preprint / Universit{\"a}t Potsdam, Fachbereich Mathematik},
  volume    = {1993, 05},
  journal   = {Preprint / Universit{\"a}t Potsdam, Fachbereich Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {9 S.},
  year      = {1993},
  language  = {en}
}
@article{Schmidt1999,
  author    = {Schmidt, Hans-J{\"u}rgen},
  title     = {The classical solutions of two-dimensional gravity},
  year      = {1999},
  language  = {en}
}
@article{SchmidtKasperKluskeetal.1995,
  author    = {Schmidt, Hans-J{\"u}rgen and Kasper, Uwe and Kluske, Sabine and Rainer, Martin and Reuter, Stefan},
  title     = {Stability properties of the Starobinsky cosmological model},
  year      = {1995},
  language  = {en}
}