Semiclassical approach to universality in quantum chaotic transport

The statistics of quantum transport through chaotic cavities with two leads is encoded in transport moments $M_m=\mathrm{T}\mathrm{r}[(t^{\mathrm{†}}t{)}^m]$, where $t$ is the transmission matrix, which have a known universal expression for systems without time-reversal symmetry. We present a semiclassical derivation of this universality, based on action correlations that exist between sets of long scattering trajectories. Our semiclassical formula for $M_m$ holds for all values of $m$ and arbitrary number of open channels. This is achieved by mapping the problem into two independent combinatorial problems, one involving pairs of set partitions and the other involving factorizations in the symmetric group.