2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/99528Convergent semiclassical trace formulae for the density of states and cohesive force of a narrow constriction in an electron gas, whose classical motion is either chaotic or integrable, are derived. It is shown that mode quantization in a metallic point contact or nanowire leads to universal oscillations in its cohesive force: the amplitude of the oscillations depends only on a dimensionless quantum parameter describing the crossover from chaotic to integrable motion, and is of order 1 nano-Newton, in agreement with recent experiments. Interestingly, quantum tunneling is shown to be described quantitatively in terms of the instability of the classical periodic orbits.corrects spelling of one author name on abstract page (paper is unchanged)Mesoscale and Nanoscale PhysicsChaotic Dynamicstext