Quantum partition noise in a superconducting tunnel junction - art. no. 180508

The theory of charge partition noise of quasiparticles in a superconducting tunnel junction is developed. The charge fluctuations are shown to have a significant contribution from partition noise that arises from the quantum superposition of the electron and hole character of the quasiparticles. The se fluctuations are dominant at small bias voltage. The charge fluctuations are compared to the usual Poisson "shot noise" of the current. The implica tions for the design of energy-resolving single-photon detectors are explor ed.