Tuning quantum fluctuations with an external magnetic field: Casimir-Polder interaction between an atom and a graphene sheet

TL;DR

This paper demonstrates how an external magnetic field can significantly control the Casimir-Polder interaction between an atom and graphene, revealing discontinuities and quantization effects linked to the quantum Hall effect, with implications for nanoscale manipulation.

Contribution

It introduces a method to tune dispersive atom-surface interactions using magnetic fields, highlighting quantum Hall effects and thermal influences in the control of Casimir-Polder forces.

Findings

Magnetic field reduces Casimir-Polder energy by up to 80%.

Discontinuities and plateau patterns emerge in the interaction energy at certain fields.

Thermal effects influence the interaction, enabling ~50% tuning without discontinuities.

Abstract

We investigate the dispersive Casimir-Polder interaction between a Rubidium atom and a suspended graphene sheet subjected to an external magnetic field B. We demonstrate that this concrete physical system allows for an unprecedented control of dispersive interactions at micro and nanoscales. Indeed, we show that the application of an external magnetic field can induce a 80% reduction of the Casimir-Polder energy relative to its value without the field. We also show that sharp discontinuities emerge in the Casimir-Polder interaction energy for certain values of the applied magnetic field at low temperatures. Moreover, for sufficiently large distances these discontinuities show up as a plateau-like pattern with a quantized Casimir-Polder interaction energy, in a phenomenon that can be explained in terms of the quantum Hall effect. In addition, we point out the importance of thermal effects in the Casimir-Polder interaction, which we show that must be taken into account even for considerably short distances. In this case, the discontinuities in the atom-graphene dispersive interaction do not occur, which by no means prevents the tuning of the interaction in ~50% by the application of the external magnetic field.