Semiclassical theory of the Ehrenfest time dependence of quantum transport in ballistic quantum dots

We present a trajectory-based semiclassical calculation of the Ehrenfest-time dependence of the weak localization correction and the universal conductance fluctuations of a ballistic quantum dot with ideal point contacts. While the weak localization correction is proportional to exp (-₄∕₃), where ₄ and ₃ are the dot's Ehrenfest time and dwell time, respectively, the variance of the conductance is found to be independent of ₄. The latter is in agreement with numerical simulations of the quantum kicked rotator J. Tworzydlo et al. , Phys. Rev. B 69, 165318 (2004) and P. Jacquod and E. V. Sukhorukov, Phys. Rev. Lett. 92, 116801 (2004).