Speaker: Massimo Macucci and Paolo Marconcini (Dipartimento di Ingegneria dell’Informazione – UNIPI)
Title: “Numerical simulation of spin-blockade effects in nanostructures for quantum computation”
Abstract:
One of the currently pursued implementations of a quantum computer is based on qubits defined in CMOS transistor structures, with a technology very close to that currently used for ordinary integrated circuits. Qubits are obtained by forming two quantum dots separated by a tunnel barrier within a transistor, with a clever exploitation of the device electrostatics. Such an approach is at present less developed than that based on superconducting qubits, since satisfactory coherence and two-qubit gates have not been achieved yet, but a significant effort is in progress because of the potential of this technology in terms of scaling up to large systems.
In this seminar, we will discuss a few aspects of the interpretation of experimental results that can be found in the literature. In particular, we will focus on the development of a numerical simulation, based on the Monte Carlo method, of networks of tunnel junctions interconnecting quantum dots, with the inclusion of the spin-blockade effect.
We start from our own simulator for single-electron circuits based on the orthodox theory of the Coulomb blockade and extend it to systems with discrete energy levels and with the spin degree of freedom.
We present some preliminary results on simple structures such as a double quantum dot connected between external leads.