EFFECT OF A VOLTAGE PROBE ON THE PHASE-COHERENT CONDUCTANCE OF A BALLISTIC CHAOTIC CAVITY

The effect of an invasive voltage probe on the phase-coherent conduction through a ballistic chaotic cavity is investigated by random-matrix theory. The entire distribution P(G) of the conductance G is computed for the case that the cavity is coupled to source and drain by two point contacts with a quantized conductance of 2e2/h, both in the presence (=1) and absence (=2) of time-reversal symmetry. The loss of phase coherence induced by the voltage probe causes a crossover from P(G)G-1+/2 to a Gaussian centered at G=e2/h with a -dependent width. © 1995 The American Physical Society.