Universal First-Passage-Time Distribution of Non-Gaussian Currents

I present our recent work on the fluctuations of the time elapsed until the electric charge transferred through
a conductor reaches a given threshold value. For this purpose, we measure the distribution of
the first-passage times for the net number of electrons transferred between two metallic islands
in the Coulomb blockade regime. Our experimental results are in excellent agreement with numerical
calculations based on a recent theory describing the exact first-passage-time distributions for any
non-equilibrium stationary Markov process.
We present a simple analytical approximation for the
first-passage-time distribution, which takes into account the non-Gaussian statistics of the electron
transport, and show that it describes the experimental distributions with high accuracy. This
universal approximation describes a wide class of stochastic processes and can be used beyond the
context of mesoscopic charge transport. In addition, we verify experimentally a fluctuation relation
between the first-passage-time distributions for positive and negative thresholds