Unveiling the bosonic nature of an ultrashort few-electron pulse

Abstract

Quantum dynamics is very sensitive to dimensionality. While two-dimensional electronic systems form Fermi liquids, one-dimensional systems—Tomonaga–Luttinger liquids—are described by purely bosonic excitations, even though they are initially made of fermions. With the advent of coherent single-electron sources, the quantum dynamics of such a liquid is now accessible at the single-electron level. Here, we report on time-of-flight measurements of ultrashort few-electron charge pulses injected into a quasi one-dimensional quantum conductor. By changing the confinement potential we can tune the system from the one-dimensional Tomonaga–Luttinger liquid limit to the multi-channel Fermi liquid and show that the plasmon velocity can be varied over almost an order of magnitude. These results are in quantitative agreement with a parameter-free theory and demonstrate a powerful probe for directly investigating real-time dynamics of fractionalisation phenomena in low-dimensional conductors.

Electron waiting times in hybrid junctions with topological superconductors

“…In coherent conductors, a measurement of the waiting time distribution seems more challenging, and only recently a quantum theory of an electron waiting time clock has been developed for normal-state conductors 41 with an extension to a spin-sensitive detector being outlined in subsequent work 87 . Recent measurements of the time-of-flight of single-electron excitations through a mesoscopic conductor provide a promising way for directly investigating real-time dynamics of emitted pulses 88,89 . Adapting these ideas to superconducting systems is clearly desirable.…”

Phase-Coherent Dynamics of Quantum Devices with Local Interactions

“…Figure 1 reports some of these experiments [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], in addition to the mesoscopic capacitor [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ], which will be extensively discussed in this review. These experiments and significant others [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ] have a common working principle: A fast [ 34 ] time-dependent voltage drive , applied either on metallic or gating contacts, triggers emission of well defined electronic excitations. Remarkably, these experiments achieved to generate, manipulate, and detect single electrons on top of a complex many-body state such as the Fermi sea.…”

Time-energy filtering of single electrons in ballistic waveguides

“…One of the crucial ingredients that has made the investigation of single electron excitations in ballistic waveguides possible is the advent of devices that emit ordered streams of electrons with sufficient separation between individual particles [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Techniques to characterize quantum properties of electrical current have been adapted from photon quantum optics.…”

“…For a Gaussian incoming wavepacket, the corresponding modified Wigner distribution can be calculated from equations(21) and(26),…”