How Huge?

Robert P Crease

Werner Heisenberg has a lot to answer for. As one of the founders of quantum mechanics, he left a huge legacy to physics. As the inventor of the uncertainty principle, he also left a huge legacy outside physics. Albert Einstein may be more widely recognized by the public – and his theory of relativity often appears in popular culture – but it is Heisenberg who has had the greater impact on public discourse.

Samuel L. Braunstein

Volker Hannstein, Gerhard C. Hegerfeldt

A simplified scheme for the investigation of cooperative effects in the quantum jump statistics of small numbers of fluorescing atoms and ions in a trap is presented. It allows the analytic treatment of three dipole-dipole interacting four-level systems which model the relevant level scheme of Ba+ ions. For the latter, a huge rate of double and triple jumps was reported in a former experiment and the huge rate was attributed to the dipole-dipole interaction. Our theoretical results show that the effect of the dipole-dipole interaction on these rates is at most 5% and that for the parameter values of the experiment there is practically no effect. Consequently it seems that the dipole-dipole interaction can be ruled out as a possible explanation for the huge rates reported in the experiment.

David Gevaux

Hiroki Kawakami, Satoshi Yamaguchi

We investigate a massive non-relativistic fermionic system exhibiting exotic features. When the mass parameter is set to zero, the system acquires the fermionic subsystem symmetry. Introducing the mass term explicitly breaks this symmetry, resulting in a trivially gapped system in the absence of boundaries. We demonstrate that with the introduction of boundaries, the system remains gapped, but it has a huge vacuum degeneracy. The residual entropy is proportional to the area of the boundary.