Spectral statistics of pointer states in open quantum dots

Pointer states are thought to control the relationship between quantum system properties and the classical results of measurement. In open quantum dots, they yield measurable conductance resonances. We study the energy level spacing statistics in a perturbed stadium dot, which, when closed, follow the Wigner distribution associated with chaos. In contrast, when the stadium is opened so that only the pointer states localized in the interior remain, the distribution becomes Poissonian, indicating that these states are intimately associated with the regular classical orbits.