Related papers: Time-resolved charge detection with cross-correlat…
The detection of the quantum dot charge state using a quantum point contact charge detector has opened a new exciting route for the investigation of quantum dot devices in recent years. In particular, time-resolved charge detection allowed…
We report high-bandwidth charge sensing measurements using a GaAs quantum point contact embedded in a radio frequency impedance matching circuit (rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to charge, we…
We report on charge sensing measurements of a GaAs semiconductor quantum dot device using a radio frequency quantum point contact (rf-QPC). The rf-QPC is fully characterized at 4 K and milli-Kelvin temperatures and found to have a bandwidth…
Laterally coupled charge sensing of quantum dots is highly desirable, because it enables measurement even when conduction through the quantum dot itself is suppressed. In this work, we demonstrate such charge sensing in a double top gated…
We solve the master equations of two charged qubits measured by two serially coupled quantum point contacts (QPCs). We describe two-qubit dynamics by comparing entangled states with product states, and show that the QPC current can be used…
We present measurements on a quantum dot and a nearby, capacitively coupled, quantum point contact used as a charge detector. With the dot being weakly coupled to only a single reservoir, the transfer of individual electrons onto and off…
We present finite bias measurements on a quantum dot coupled capacitively to a quantum point contact used as a charge detector. The transconductance signal measured in the quantum point contact at finite dot bias shows structure which…
Time-resolved electron dynamics in coupled quantum dots is directly observed by a pulsed-gate technique. While individual gate voltages are modulated with periodic pulse trains, average charge occupations are measured with a nearby quantum…
We use time-resolved charge detection techniques to investigate single-electron tunneling in semiconductor quantum dots. The ability to detect individual charges in real-time makes it possible to count electrons one-by-one as they pass…
A double quantum dot charge detector, with one dot Coulomb coupled to the electron to be detected and the other modulated by a time-dependent plunger voltage, is analyzed in a minimal model. The signal and noise of the detector are…
Measurement of charge configurations in few-electron quantum dots is a vital technique for spin-based quantum information processing. While fast and high-fidelity measurement is possible by using proximal quantum dot charge sensors, their…
High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a…
We report raster scan multiplexed charge-stability diagram measurements for tuning multiple gate-defined quantum dots in GaAs/AlGaAs heterostructures. We evaluate the charge sensitivity of the quantum point contact (QPC) in both radio…
The single electron transistor (SET) is a prime candidate for reading out the final state of a qubit in a solid state quantum computer. Such a measurement requires the detection of sub-electron charge motion in the presence of random…
We observe individual tunnel events of a single electron between a quantum dot and a reservoir, using a nearby quantum point contact (QPC) as a charge meter. The QPC is capacitively coupled to the dot, and the QPC conductance changes by…
We have operated a quantum point contact (QPC) charge detector in a radio frequency (RF) mode that allows fast charge detection in a bandwidth of tens of megahertz. We find that the charge sensitivity of the RF-QPC is limited not by the…
We present a scheme for tuning two quantum point contacts as a quantum-limited charge detector. Based on the scattering matrix approach, we analyze a general condition of quantum-limited detection with a single-channel quantum detector…
The implementation of a quantum computer requires a qubit-specific measurement capability to read-out the final state of a quantum system. The model of spin dependent tunneling followed by charge readout has been highly successful in…
The detection of objects in the presence of significant background noise is a problem of fundamental interest in sensing. In this work, we theoretically analyze a prototype target detection protocol, the quantum temporal correlation (QTC)…
We describe the construction and operation of a two-channel noise detection system for measuring power and cross spectral densities of current fluctuations near 2 MHz in electronic devices at low temperatures. The system employs cryogenic…