Related papers: Quantum-limited charge detection with two quantum …
We address the ultimate charge detection scheme with a quantum point contact. It is shown that a superposed input state is necessary to exploit the full sensitivity of a quantum point contact detector. The coherence of the input state…
Nanostructures defined in high-mobility two-dimensional electron systems offer a unique way of controlling the microscopic details of the investigated device. Quantum point contacts play a key role in these investigations, since they are…
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 present time-resolved charge sensing measurements on a GaAs double quantum dot with two proximal quantum point contact (QPC) detectors. The QPC currents are analyzed with cross-correlation techniques, which enables us to measure dot…
Quantum detector properties of the quantum point contact (QPC) are analyzed for arbitrary electron transparency and coupling strength to the measured system and are shown to be determined by the electron counting statistics. Conditions of…
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 a scheme for high sensitivity charge detection in the integer quantum Hall regime using two point contacts in a series. The setup is an electronic analog of an optical Fabry-Perot interferometer. We show that for small…
In order to employ solid state quantum dots as qubits, both a high degree of control over the confinement potential as well as sensitive charge detection are essential. We demonstrate that by combining local anodic oxidation with local…
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 performed measurements on a quantum dot and a capacitively coupled quantum point contact by using the sharp metallic tip of a low-temperature scanning force microscope as a scanned gate. The quantum point contact served as a detector for…
We use a double quantum dot as a frequency-tunable on-chip microwave detector to investigate the radiation from electron shot-noise in a near-by quantum point contact. The device is realized by monitoring the inelastic tunneling of…
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…
We demonstrate real-time detection of self-interfering electrons in a double quantum dot embedded in an Aharonov-Bohm interferometer, with visibility approaching unity. We use a quantum point contact as a charge detector to perform…
We present a method to detect properties of quantum channels, assuming that some a priori information about the form of the channel is available. The method is based on a correspondence with entanglement detection methods for multipartite…
We investigate theoretically a novel type of high frequency quantum detector based on the mesoscopic capacitor recently realized by Gabelli et al., [Science {\bf 313}, 499 (2006)], which consists of a quantum dot connected via a single…
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…
In this letter, we have considered an electron in a double quantum dot system interacting with a detector represented by a point contact. We present a dynamical model for the gradual decoherence of the density matrix due to the interaction…
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…
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…
We formulate general conditions necessary for a linear-response detector to reach the quantum limit of measurement efficiency, where the measurement-induced dephasing rate takes on its minimum possible value. These conditions are applicable…