High Frequency Dynamics and Third Cumulant of Quantum Noise

The existence of the third cumulant $S_{3}$ of voltage fluctuations has demonstrated the non-Gaussian aspect of shot noise in electronic transport. Until now, measurements have been performed at low frequency, \textit{i.e.} in the classical regime $\hbar \omega < eV, k_BT$ where voltage fluctuations arise from charge transfer process. We report here the first measurement of $S_3$ at high frequency, in the quantum regime $\hbar \omega > eV, k_BT$. In this regime, experiment cannot be seen as a charge counting statistics problem anymore. It raises central questions of the statistics of quantum noise: 1) the electromagnetic environment of the sample has been proven to strongly influence the measurement, through the possible modulation of the noise of the sample. What happens to this mechanism in the quantum regime? 2) For $\hbar \omega > eV$, the noise is due to zero point fluctuations and keeps its equilibrium value: $S_2= G \hbar \omega$ with $G$ the conductance of the sample. Therefore, $S_2$ is independent of the bias voltage and no photon is emitted by the conductor. Is it possible, as suggested by some theories, that $S_3 \neq 0$ in this regime? With regard to these questions, we give theoretical and experimental answers to the environmental effects showing that they involve dynamics of the quantum noise. Using these results, we investigate the question of the third cumulant of quantum noise in the a tunnel junction

Integer and fractional charge Lorentzian voltage pulses analyzed in the frame of Photon-assisted Shot Noise

The periodic injection $n$ of electrons in a quantum conductor using periodic voltage pulses applied on a contact is studied in the energy and time-domain using shot noise computation in order to make comparison with experiments. We particularly consider the case of periodic Lorentzian voltage pulses. When carrying integer charge, they are known to provide electronic states with a minimal number of excitations, while other type of pulses are all accompanied by an extra neutral cloud of electron and hole excitations. This paper focuses on the low frequency shot noise which arises when the pulse excitations are partitioned by a single scatterer in the framework of the Photo Assisted Shot Noise (PASN) theory. As a unique tool to count the number of excitations carried per pulse, shot noise reveals that pulses of arbitrary shape and arbitrary charge show a marked minimum when the charge is integer. Shot noise spectroscopy is also considered to perform energy-domain characterization of the charge pulses. In particular it reveals the striking asymmetrical spectrum of Lorentzian pulses. Finally, time-domain information is obtained from Hong Ou Mandel like noise correlations when two trains of pulses generated on opposite contacts collide on the scatterer. As a function of the time delay between pulse trains, the noise is shown to measure the electron wavepacket autocorrelation function for integer Lorentzian thanks to electron antibunching. In order to make contact with recent experiments all the calculations are made at zero and finite temperature

Single-electron current sources: towards a refined definition of ampere

Controlling electrons at the level of elementary charge $e$ has been demonstrated experimentally already in the 1980's. Ever since, producing an electrical current $ef$, or its integer multiple, at a drive frequency $f$ has been in a focus of research for metrological purposes. In this review we first discuss the generic physical phenomena and technical constraints that influence charge transport. We then present the broad variety of proposed realizations. Some of them have already proven experimentally to nearly fulfill the demanding needs, in terms of transfer errors and transfer rate, of quantum metrology of electrical quantities, whereas some others are currently "just" wild ideas, still often potentially competitive if technical constraints can be lifted. We also discuss the important issues of read-out of single-electron events and potential error correction schemes based on them. Finally, we give an account of the status of single-electron current sources in the bigger framework of electric quantum standards and of the future international SI system of units, and briefly discuss the applications and uses of single-electron devices outside the metrological context.Comment: 55 pages, 38 figures; (v2) fixed typos and misformatted references, reworded the section on AC pump

Time-resolved quantum correlations in electronic noise

The statistics of quantum transport in nanostructures can be tailored by a time-dependent bias voltage $V(t)$. We demonstrate experimentally how correlations of current fluctuations at two different times $t$ and $t+\tau$ depend on the shape of $V(t)$ via the phase accumulated by the electronic wavefunctions between $t$ and $t+\tau$. For this we measure the current-current correlation of the shot noise of an ac+dc biased tunnel junction using a 10 GHz bandwidth, time-resolved detection. Our result allows to explore correlations within a single excitation period. It demonstrates the counterpart of the ac Josephson effect in superconducting junctions, to a normal, non-superconducting mesoscopic device

A Josephson relation for fractionally charged anyons.

Anyons occur in two-dimensional electron systems as excitations with fractional charge in the topologically ordered states of the fractional quantum Hall effect (FQHE). Their dynamics are of utmost importance for topological quantum phases and possible decoherence-free quantum information approaches, but observing these dynamics experimentally is challenging. Here, we report on a dynamical property of anyons: the long-predicted Josephson relation f J = e*V/h for charges e* = e/3 and e/5, where e is the charge of the electron and h is Planck's constant. The relation manifests itself as marked signatures in the dependence of photo-assisted shot noise (PASN) on voltage V when irradiating contacts at microwaves frequency f J The validation of FQHE PASN models indicates a path toward realizing time-resolved anyon sources based on levitons

Molecular electronic plasmonics

AbstractMolecular electronic plasmonics (MEP) is an area of research that utilizes the electronic properties of molecules to control and modulate surface plasmons and holds the potential to develop on-chip integrated molecular-plasmonic devices for information processing and computing. Combining molecular electronics with plasmonics gives the opportunity to study both charge transport in molecular electronic devices and plasmonics in the quantum regime. Here, we review the recent progress in molecular electronic plasmonics and mainly focus on the areas of quantum plasmonics, and plasmon excitation and detection. This review also identifies challenges that need to be resolved to drive this field forward including improving models aimed to advance our understanding of electron-plasmon interactions in the quantum tunneling regime. Future progresses can be expected towards incorporating functional molecules to actively control MEP devices and integration of MEPs with other circuit components

Infrared receivers for low background astronomy: Incoherent detectors and coherent devices from one micrometer to one millimeter

The status of incoherent detectors and coherent receivers over the infrared wavelength range from one micrometer to one millimeter is described. General principles of infrared receivers are included, and photon detectors, bolometers, coherent receivers, and important supporting technologies are discussed, with emphasis on their suitability for low background astronomical applications. Broad recommendations are presented and specific opportunities are identified for development of improved devices