The Casimir effect in graphene systems: Experiment and theory

The Casimir effect in graphene systems is reviewed with emphasis made on the large thermal correction to the Casimir force predicted at short separations between the test bodies. The computational results for the Casimir pressure and for the thermal correction are presented for both pristine graphene and real graphene sheets, which possess nonzero energy gap and chemical potential, obtained by means of exact polarization tensor. Two experiments on measuring the gradient of the Casimir force between an Au-coated sphere and graphene- coated substrates performed by using a modified atomic force microscope cantilever-based technique are described. It is shown that the measurement data of both experiments are in agreement with theoretical predictions of the Lifshitz theory using the polarization tensor. Additionally, several important improvements made in the second experiment, allowed to demonstrate the predicted large thermal effect in the Casimir interaction at short separations. Possible implications of this result to resolution of long-term problems of Casimir physics are discussed.
Comment: 22 pages, 6 figures; accepted for publication in the Special Issue of Int. J. Mod. Phys. A "The State of Quantum Vacuum: Casimir Physics in the 2020s" (Edited by Prof. K. A. Milton)