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A radio-frequency single-electron transistor (RF-SET) coupled to a
quantum dot in a GaAs heterostructure. The RF-SET can be used to
monitor the motion of individual electrons on and of the dot in a time
as short as one microsecond.
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A single tunnel junction embedded in an engineered electromagnetic environment in GaAs
heterostructure. The enviromental impedance seen by the tunnel junction is determined by arrays of
quantum point contacts on either side of the tunnel barrier. An RF-SET is integrated with the
structure to allow monitoring of individual tunnel events through the central barrier.
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An RF-SET coupled to a double-quantum dot in a GaAs heterostructure. The RF-SET can be used to
monitor the charge state of one of the dots, thereby allowing individual electron tunneling events
between the dots to be observed. Conversely, the double dot can be used as a spectrum analyzer to
measure the backaction spectrum of the SET.
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A single electron transistor fabricated on a substrate containing a two-dimensional electron gas in a
SiGe heterostructure. The electron spin of a quantum dot in such a heterostructure is expected to
show very long coherence times, making them good candidates for quantum information processing.
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Superconducting single-electron transistor (S-SET) fabricated above a quantum dot in a GaAs
heterostructure. The quantum dot can be used as a tunable electromagnetic environment for studies of
the effects of dissipation on coherent processes in the S-SET.
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A spiral Nb chip inductor fabricated by P. Dresselhaus of NIST Boulder for use in impedance-matching
an SET to a coaxial line. Since the Nb is superconducting, it has very little loss, making the
matching more efficient. More complex matching networks made in a similar fashion could be used in
the future for improved matching bandwidth.
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