Selected Publications

Quantum theory as optimal encoding of probabilistic information
       Johann Summhammer
       Paper presented at International Conference on Quantum Structures, Vienna, July 1 - 7, 2002
          Quantum experiments yield random data. We show that the most efficient way to store
          this empirical information by a finite number of bits is by means of the vector of square
          roots of observed relative frequencies. This vector has the unique property that its dispersion
          becomes invariant of the underlying probabilities, and therefore invariant of the physical
          parameters. This also extends to the complex square roots, and it remains true under
          a unitary transformation effected by a quantum evolution. This reveals quantum theory
          as a statistical theory of making predictions which are as accurate as the input information,
         without any statistical loss. Our analysis also suggests that from the point of view of
          information a slightly more accurate theory than quantum theory should be possible.
Full paper (PDF, 223k: 14 pages, including 5 figures)

Online version available!

J. Summhammer, K.A. Hamacher, H. Kaiser, H. Weinfurter, D.L.Jacobsonand S.A. Werner
Published in: Phys.Rev.Lett 75, 3206 (1995).
Polarized neutron interferometry has been used to measure the amplitudesforthe exchange of up to five photons between the neutron and an oscillatingmagneticfield. The Rabi spin flip configuration and a configuration in whichspinflip is suppressed were investigated, because they raise differentquestionson the conservation of angular momentum. Due to the linearity ofthe time-dependentinterference signal in the exchange amplitudes , photonexchangeprobabilities below one percent could be resolved.

  • Testing Energy Quantization at the Level of 100 kHz by Neutron Crystal Diffraction

Published in: Phys.Rev.A 54, 3155 (1996).
For the study of energy quantization in low frequency potentials andtheaccompanying quantum effects we analyze a silicon double crystal arrangementexploitingdynamical diffraction of neutrons to achieve the required extremelyhighenergy resolution. The first crystal prepares a minimumuncertainty beamwhich passes a potential region whose influence on theneutron energy isanalyzed by the second crystal. With realistic parameterschanges of neutronenergy below 0.5 neV can be resolved. This permits a testof quantized energytransfer in periodically time dependent potentials of afrequency below100 kHz. We also discuss three specific examples how to observethe quantumphenomena arising from the macroscopic wavepackets therebygenerated.

G.Krenn, J.Summhammer, K.Svozil
Online version available!

G.Krenn, A.Zeilinger
Online version available!

G.Krenn, K.Svozil
Online version available!

Changes by J.Summhammer 4.Apr.2003