The use of quantum dots in the nascent field of quantum computation has brought forth a revival in interest in this area of condensed matter physics. One of the candidates for a qubit is the manipulation of electron spin, as proposed in DiVincenzo et al (cond-mat/9911245). The electron spin is a robust candidate for a qubit because of the particularly long coherence time (both T1 and T2) for the electron spin, the fact that the spins can be spatially transported via an electric field, and the scalability of the fabrication of quantum dots. By electrostactically coupling two single dots, one obtains a tunable two-level system for electronic energy states. Our current focus in this area is the local manipulation of electronic spins via a spin resonant technique in a few electron double dot. These dots are fabricated using electron beam lithography on epitaxially grown GaAs/AlGaAs heterostructures.
The following figure illustrates a quantum dot-based quantum computer proposed by Loss et al. (cond-mat/0004182). Spin confinement and transfer is utilized via standard methods in quantum dots. Spin rotation is control via an ESR field and can be control local via utilization of the high g layer.
For more information contact Jason Petta (petta@deas), James Williams (jrwill@fas), or Abram Falk (falk@fas).