Bohr and Dirac

We present an account of the work of Niels Bohr and Paul Dirac, their interactions and personalities

Playing with sandpiles

The Bak-Tang-Wiesenfeld sandpile model provdes a simple and elegant system with which to demonstate self-organized criticality. This model has rather remarkable mathematical properties first elucidated by Dhar. I demonstrate some of these properties graphically with a simple computer simulation.Comment: Contribution to the Niels Bohr Summer Institute on Complexity and Criticality; to appear in a Per Bak Memorial Issue of PHYSICA A; 6 pages 3 figure

Microphysics in Computational Relativistic Astrophysics - MICRA2009, Niels Bohr International Academy, Copenhagen, 24–28 August 2009

This special section is devoted to the workshop `Microphysics in Computational Relativistic Astrophysics - MICRA2009', which took place at the Niels Bohr International Academy, in Copenhagen, 24–28 August 2009

Rejection of the Light Quantum: The Dark Side of Niels Bohr

Evidence is recalled of the strong opposition of Niels Bohr, at the time of the Old Quantum Theory 1.913-25, to the Lichtquanten hypothesis of Einstein. Some episodes with H.A. Kramers, J.C. Slater and W. Heisenberg are recollected; Bohr's changing point of view is traced back to some philosophical antecedents and to his endeavour to deduce quantum results from the Correspondence Principle. Some consequences for the future interpretation of Quantum Mechanics, specially to the Complementarity Principle, are considered.Comment: 15 page