Chiral Casimir forces: Repulsive, enhanced, tunable

Abstract

Both theoretical interest and practical significance attach to the sign and strength of Casimir forces. A famous, discouraging no-go theorem states that "The Casimir force between two bodies with reflection symmetry is always attractive." Here we identify a loophole in the reasoning, and propose a universal way to realize repulsive Casimir forces. We show that the sign and strength of Casimir forces can be adjusted by inserting optically active or gyrotropic media between bodies, and modulated by external fields.Identifying the loophole: To begin, we briefly review the "Casimir" energy in massless free scalar field theory.

Anomalous Casimir effect in axion electrodynamics

“…Then, despite physical distinction between the chirality origins in their and our studies, the formula derived in Ref. [45] is directly applicable for our current setup. To this end, we just need to replace their dispersion relation (A1) with ours in Eq.…”

“…Lately, in a simpler setup even without interaction effects, a tunable Casimir force that can oscillate between attractive and repulsive has been derived by Ref. [45]. In their scenario, the key point lies in that the chiral media, i.e., optically active or gyrotropic media, endow the vacuum with an intrinsic breaking of spatial parity P and/or time reversal T symmetries.…”

Cavity quantum electrodynamical Chern insulator: Towards light-induced quantized anomalous Hall effect in graphene

“…In quantum optics the potential of chiral lightmatter coupling has been recognized to bear potential for instance for the design of ultrafast optical switches or nonreciprocal devices [43], and chiral exciton-plasmon coupling has been demonstrated experimentally [44]. Recently chiral light-matter coupling in cavities has been suggested to reverse the sign of the Casimir force between the metallic plates [45].…”

Quantum atmospherics for materials diagnosis

“…(See Figure 1.) The atmosphere induces new kinds of "Casimir" forces on bodies near the material [14][15][16][17][18]. It also induces new kinds of effective interactions within atoms or molecular centers, which affect their spectra.…”