26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Floquet engineered Nonequilibrium Dispersion Interactions and Coulomb Drag in current-carrying nanostructures

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral AIP | Quantum Science and Technology (QST)

Speaker

Christine Little (James Cook University)

Description

Understanding and controlling long-range interaction effects in nonequilibrium quantum systems is a key challenge in quantum physics that underpins emerging quantum technologies. This has applications across quantum transport, nanoscale force engineering and quantum information processing.

Stemming from correlated quantum fluctuations, dispersion forces between two current-carrying nanostructures can be controlled by an applied voltage bias which drives each open quantum system into a nonequilibrium steady state [1]. This demonstrates a fluctuation-dissipation description of the dispersion interaction energy where charge noise fluctuations of one system couples with the dissipative charge response of the other system. A static voltage bias can control both the magnitude of the attractive dispersion interactions between the systems and lead to repulsive dispersion interactions under the condition of population inversion in the electron reservoirs which are coupled to the quantum nanostructures.

By applying an external time-dependent driving through an AC bias across the leads we can investigate the potential for AC controlled nonequilibrium dispersion interactions and Coulomb drag between two quantum nanostructures, each coupled to individual electron reservoirs. The nanostructures interact only through Coulomb interactions with no direct electron tunnelling between them. We present a Floquet-nonequilibrium Green’s function theory for modelling the time-dependent quantum transport in these correlated quantum systems. The theory allows us to explore how periodic driving can be used to engineer attractive-repulsive switching of the dispersion interactions and alter the standard picture of Coulomb drag. Our results demonstrate that nonequilibrium dispersion interactions and Coulomb drag can be actively controlled by AC driving, which has interesting implications for Floquet engineered forces at the nanoscale and quantum transport.

[1] C. M. E. Little and D. S. Kosov (2026) arxiv.org/abs/2605.02315 J. Chem. Phys. in press.