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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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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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Optical micrograph of a GaAs chip containing a two-dimensional electron gas. The chip
includes a double quantum dot with integrated nanomagnet, as well as an on-chip
superconducting spiral inductor for impedance matching a radio-frequency quantum point
contact to a 50 Ohm coaxial feedline.
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A coplanar-waveguide resonator including two waveguide-based dc feedlines terminated in spiral inductors. Similar structures will be
used to investigate quantum nonlinear dynamics and the quantum to classical transition.
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Closeup view of a double quantum dot designed for electron spin resonance measurements. The
on-chip matching network (a superconducting spiral) for fast charge detection is visible on the
right.
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Measured effective temperature and damping rate for a superconducting single electron
transistor (S-SET) operating near the quantum limit. Together these provide a complete and
quantitative description of the S-SET quantum noise
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Sample mount with custom designed pc board and off-chip stripline for electron-spin resonance (ESR) measurements in
double quantum dots. The ESR field will allow coherent manipulation of electron spin on the two dots.
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Conductance of a superconducting single electron transistor versus gate and bias voltage.
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Conductance of a few-electron Si/SiGe quantum dot versus gate and bias voltage.
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Calculated pieozoelectric polarization field for a GaAs crystal vibrating in a flexural normal mode. Electomechanical
coupling between this strain field and current through a quantum point contact (QPC) allows the mesoscopic shot noise of the
QPC to drive a macroscopic mechanical resonance of the host crystal.
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Few-electron double quantum dot (DQD) gate pattern with an integrated nanomagnet (red). A gap in the gate on the left will
allow a single electron transistor to be coupled to the DQD for charge sensing.
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Single electron transistor coupled to a Si/SiGe few-electron double quantum dot.
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Aluminum on-chip spiral used for impedance matching a superconducting single electron transistor to a coaxial feedline.
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