Electron counting in quantum dots

Abstract

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 through the structure. The setup can thus be used as a high-precision current meter for measuring ultra-low currents, with resolution several orders of magnitude better than that of conventional current meters. In addition to measuring the average current, the counting procedure also makes it possible to investigate correlations between charge carriers. In quantum dots, we find that the strong Coulomb interaction makes electrons try to avoid each other. This leads to electron anti-bunching, giving stronger correlations and reduced noise compared to a current carried by statistically independent electrons. The charge detector is implemented by monitoring changes in conductance in a near-by capacitively coupled quantum point contact. We find that the quantum point contact not only serves as a detector but also causes a back-action onto the measured device. Electron scattering in the quantum point contact leads to emission of microwave radiation. The radiation is found to induce an electronic transition between two quantum dots, similar to the absorption of light in real atoms and molecules. Using a charge detector to probe the electron transitions, we can relate a single-electron tunneling event to the absorption of a single photon. Moreover, since the energy levels of the double quantum dot can be tuned by external gate voltages, we use the device as a frequency-selective single-photon detector operating at microwave energies.

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Cited by in corpus (28)

• Scalable gate architecture for densely packed semiconductor spin qubits
• Counting statistics of transport through Coulomb blockade nanostructures: High-order cumulants and non-Markovian effects
• Factorial cumulants reveal interactions in counting statistics
• Systematic approach to statistics of conductance and shot-noise in chaotic cavities
• Electron Waiting Times in Non-Markovian Quantum Transport
• Superconducting proximity effect in interacting quantum dots revealed by shot noise
• Time-resolved charge detection in graphene quantum dots
• Measuring the degeneracy of discrete energy levels using a GaAs/AlGaAs quantum dot
• Electronic waiting-time distribution of a quantum-dot spin valve
• Full counting statistics and shot noise of cotunneling in quantum dots and single-molecule transistors
• Quantum Thermodynamics with Degenerate Eigenstate Coherences
• Transient fluctuation relations for time-dependent particle transport
• Entanglement entropy in dynamic quantum-coherent conductors
• Nonrenewal statistics in transport through quantum dots
• Waiting time distribution revealing the internal spin dynamics in a double quantum dot
• Electron waiting times of a periodically driven single-electron turnstile
• Non-renewal statistics in quantum transport through the eyes of first-passage and waiting time distributions
• Non-Markovian dynamics of a nanomechanical resonator measured by a quantum point contact
• Majorana Entanglement Bridge
• Identifying single electron charge sensor events using wavelet edge detection
• Inverse counting statistics based on generalized factorial cumulants
• Nonequilibrium noise and current fluctuations at the superconducting phase transition
• Direct Entropy Measurement in a Mesoscopic Quantum System
• Crossover of thermal to shot noise in chaotic cavities
• Conditional counting statistics of electrons tunneling through quantum dot systems measured by a quantum point contact
• Entanglement Distribution Statistic in Andreev Billiards
• Klein Paradox in Chaotic Dirac Billiards
• Revealing the internal spin dynamics in a double quantum dot by periodic voltage modulation