Strong Charge Fluctuations in the Single-Electron Box: A Quantum Monte Carlo Analysis
Path-integral Monte Carlo simulations have been employed to study strong electron tunneling in the single-electron box (a small metallic island coupled to an electrode by a tunnel junction). Results will be presented for the free energy of this system, as well as for the average charge on the island, as a function of the tunneling strength, the temperature, and an external bias voltage. In much of the parameter range an extrapolation to the ground state (T = 0) is possible. Our results for the effective charging energy for strong tunneling will be compared with earlier theoretical predictions and Monte Carlo simulations.