@article{Baumgaertel2011,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {A Characteristic decay semigroup for the resonances of trace class perturbations with analyticity conditions of semibounded hamiltonians},
  series = {International journal of theoretical physic},
  volume    = {50},
  journal   = {International journal of theoretical physic},
  number    = {7},
  publisher = {Springer},
  address   = {New York},
  issn      = {0020-7748},
  doi       = {10.1007/s10773-010-0533-9},
  pages     = {2002 -- 2008},
  year      = {2011},
  abstract  = {To asymptotic complete scattering systems {M(+) + V, M(+)} on H(+) := L(2)(R(+), K, d lambda), where M(+) is the multiplication operator on H(+) and V is a trace class operator with analyticity conditions, a decay semigroup is associated such that the spectrum of the generator of this semigroup coincides with the set of all resonances (poles of the analytic continuation of the scattering matrix into the lower half plane across the positive half line), i.e. the decay semigroup yields a "time-dependent" characterization of the resonances. As a counterpart a "spectral characterization" is mentioned which is due to the "eigenvalue-like" properties of resonances.},
  language  = {en}
}
@book{Baumgaertel1994,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {A modified approach to the Doplicher-Roberts theorem on the construction of field algebra and the symmetry group in superselection theory},
  series = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  volume    = {134},
  journal   = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  address   = {Berlin},
  pages     = {33 S.},
  year      = {1994},
  language  = {en}
}
@article{Baumgaertel1997,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {A modified approach to the Doplicher-Roberts theorem on the construction of the field algebra and the symmetry group in superselection theory},
  year      = {1997},
  language  = {en}
}
@book{BaumgaertelJurkeLledo1994,
  author    = {Baumg{\"a}rtel, Hellmut and Jurke, Matthias and Lled{\´o}, Fernando},
  title     = {A remark on covariant and causal nets of CAR-resp.CCR-type local algebras assigned to the irreducible unitary representation of the poincare group labeled by (m>0, s, +)},
  series = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  volume    = {120},
  journal   = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  address   = {Berlin},
  year      = {1994},
  language  = {en}
}
@book{Baumgaertel1999,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Actions of finite abelian groups on abelian C*-algebras Z: Second cohomology and description by C*-extensions F ) Z},
  series = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  volume    = {383},
  journal   = {Preprint / SFB 288, Differentialgeometrie und Quantenphysik},
  address   = {Berlin},
  year      = {1999},
  language  = {en}
}
@article{Baumgaertel2001,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {An Application of the DR-Duality Theory for Compact Groups to Endomorphism Categories of C*-Algebras with Nontrivial Center},
  year      = {2001},
  language  = {en}
}
@article{Baumgaertel1999,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {An inverse problem for superselection structures on C*-algebras with nontrivial center},
  year      = {1999},
  language  = {en}
}
@book{Baumgaertel1997,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Betrachtungen zur kulturellen Dimension der Mathematik},
  series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  volume    = {1997, 15},
  journal   = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Mathematik},
  publisher = {Univ.},
  address   = {Potsdam},
  pages     = {17 S.},
  year      = {1997},
  language  = {de}
}
@book{Baumgaertel1999,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Cuntz algebras and superselection structures in Quantum Field Theory},
  series = {LQP Papers / Local Quantum Physics Crossroads},
  journal   = {LQP Papers / Local Quantum Physics Crossroads},
  publisher = {Univ.},
  address   = {G{\"o}ttingen},
  year      = {1999},
  language  = {en}
}
@article{Baumgaertel2000,
  author    = {Baumg{\"a}rtel, Hellmut},
  title     = {Dual actions on C*-algebras and Hilbert extensions},
  year      = {2000},
  language  = {en}
}