@article{HoffmannBostroemFelbinger2005,
  author    = {Hoffmann, H. and Bostr{\"o}m, Kim and Felbinger, Timo},
  title     = {Comment on Secure direct communication with a quantum one-time pad},
  year      = {2005},
  abstract  = {In the paper [Phys. Rev. A 69, 052319 (2004)], a quantum direct communication protocol is proposed which is claimed to be unconditionally secure even for the case of a noisy channel. We show that this is not the case by giving an undetectable attack scheme},
  language  = {en}
}
@article{HoffmannSeissSpahn2013,
  author    = {Hoffmann, H. and Seiß, Martin and Spahn, Frank},
  title     = {Vertical relaxation of a moonlet propeller in Saturn's a ring},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  volume    = {765},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  number    = {1},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {2041-8205},
  doi       = {10.1088/2041-8205/765/1/L4},
  pages     = {3},
  year      = {2013},
  abstract  = {Two images, taken by the Cassini spacecraft near Saturn's equinox in 2009 August, show the Earhart propeller casting a 350 km long shadow, offering the opportunity to watch how the ring height, excited by the propeller moonlet, relaxes to an equilibrium state. From the shape of the shadow cast and a model of the azimuthal propeller height relaxation, we determine the exponential cooling constant of this process to be lambda = 0.07 +/- 0.02 km(-1), and thereby determine the collision frequency of the ring particles in the vertically excited region of the propeller to be omega(c)/Omega = 0.9 +/- 0.2.},
  language  = {en}
}