Quantum Electron Dynamics in Mesoscopic Systems

Mesoscopic systems occupy the scale between individual atoms and bulk conductors, where electronic wave coherence and quantised energy spectra govern transport. In this regime, the interplay of quantum interference, Coulomb interactions and topological constraints gives rise to phenomena such as quantised conductance steps, Coulomb blockade, charge fractionalisation and non-classical current correlations. Low-dimensional heterostructures fabricated with two-dimensional electron gases or semiconducting nanowires enable precise control of single-electron sources, coherent edge channels and one-dimensional conductors. Techniques drawn from electron quantum optics—such as interferometry, tomography and surface acoustic wave transport—permit direct probing and manipulation of individual electron wavepackets, revealing their coherence properties, squeezing of collective modes and emergence of non-thermal many-body states. These advances underpin proposals for flying-qubit architectures, quantum information processors and primary standards of electric current, and they deepen our understanding of electron-electron interactions in low dimensions.

Research from Nature Portfolio

Recent studies have revealed that injecting extremely hot electrons into chiral quantum Hall edge channels produces long-lived non-thermal Tomonaga-Luttinger liquid states, in which warm and cold electron populations coexist without further thermalisation, underscoring the robustness of one-dimensional integrable models. Building on this, experiments using surface acoustic waves in piezoelectric heterostructures have achieved directional, on-chip transfer of single electrons between distant quantum dots with efficiencies exceeding 99 %, demonstrating two key building blocks for scalable flying-qubit circuits. Complementary work has developed quantum-tomography protocols that combine two-particle interferometry with signal processing to reconstruct the Wigner representation of electron and hole wavefunctions emitted by on-demand sources, thereby quantifying coherence, chirp and squeezing in time-dependent electrical currents.

Quantum Electron Dynamics in Mesoscopic Systems publication trend

The graph below shows the total number of articles in quantum electron dynamics in mesoscopic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Mesoscopic system: A conductor whose dimensions lie between atomic and macroscopic scales, where quantum coherence and discrete energy levels dominate transport.

Tomonaga-Luttinger liquid: A theoretical description of interacting electrons in one dimension, characterised by collective bosonic modes rather than individual quasiparticles.

Quantum Hall edge channel: A unidirectional conduction path at the boundary of a two-dimensional electron system under strong magnetic fields, supporting chiral electron flow.

Surface acoustic wave (SAW): A mechanical wave travelling along the surface of a piezoelectric material, used to shuttle single electrons in coupled semiconductor devices.

Wigner function: A phase-space representation of a quantum state, combining position (or time) and momentum (or energy) distributions to characterise coherence and correlations.

Single-electron pump: A nanoscale device that transfers individual electrons in a controlled, quantised fashion per driving cycle, enabling precise current standards.

References

1. Observation of Edge Magnetoplasmon Squeezing in a Quantum Hall Conductor. Physical Review Letters (2023).
2. Multiple electron pumping. EPJ Quantum Technology (2023).
3. Non-thermal Tomonaga-Luttinger liquid eventually emerging from hot electrons in the quantum Hall regime. Communications Physics (2023).
4. Sound-driven single-electron transfer in a circuit of coupled quantum rails. Nature Communications (2019).
5. Continuous-variable tomography of solitary electrons. Nature Communications (2019).