Quantum dot admittance probed at microwave frequencies with an on-chip resonator
Physical Review B - Condensed Matter and Materials Physics 86:11 (2012)
Abstract:
We present microwave frequency measurements of the dynamic admittance of a quantum dot tunnel-coupled to a two-dimensional electron gas. The measurements are made via a high-quality 6.75 GHz on-chip resonator capacitively coupled to the dot. The resonator frequency is found to shift both down and up close to conductance resonance of the dot corresponding to a change of sign of the reactance of the system from capacitive to inductive. The observations are consistent with a scattering matrix model. The sign of the reactance depends on the detuning of the dot from conductance resonance and on the magnitude of the tunnel rate to the lead with respect to the resonator frequency. Inductive response is observed on a conductance resonance when tunnel coupling and temperature are sufficiently small compared to the resonator frequency. © 2012 American Physical Society.Dipole Coupling of a Double Quantum Dot to a Microwave Resonator
PHYSICAL REVIEW LETTERS 108:4 (2012) ARTN 046807
Correlation measurements of individual microwave photons emitted from a symmetric cavity
Journal of Physics: Conference Series 264:1 (2011)
Abstract:
Superconducting circuits have been successfully established as systems to prepare and investigate microwave light fields at the quantum level. In contrast to optical experiments where light is detected using photon counters, microwaves are usually measured with well developed linear amplifiers. This makes measurements of correlation functions - one of the important tools in optics - harder to achieve because they traditionally rely on photon counters and beam splitters. Here, we demonstrate a system where we can prepare on demand single microwave photons in a cavity and detect them at the two outputs of the cavity using linear amplifiers. Together with efficient data processing, this allows us to measure different observables of the cavity photons, including the first-order correlation function. Using these techniques we demonstrate cooling of a thermal background field in the cavity. © Published under licence by IOP Publishing Ltd.Characterization of a microwave frequency resonator via a nearby quantum dot
APPLIED PHYSICS LETTERS 98:26 (2011) ARTN 262105
Fabrication and heating rate study of microscopic surface electrode ion traps
NEW JOURNAL OF PHYSICS 13 (2011) ARTN 013032