Scientific Calendar Event

Starts 5 Jun 2024 15:00
Ends 5 Jun 2024 16:00
Central European Time
Leonardo Building, Luigi Stasi Seminar Room (and via Zoom)

Ali Naji
(Institute for Research in Fundamental Sciences)
Ferrofluids are stabilized suspensions of superparamagnetic nanoparticles in a nonmagnetic liquid. They have emerged as an important class of materials with tunable properties, making them relevant also to the control of Casimir effect in small-scale applications. The Casimir effect arises from omnipresent quantum vacuum fluctuations, leading to ubiquitous attractive forces between material bodies. We discuss how different properties of ferrofluids, such as their restructuring and anisotropic response to an applied magnetic field, can be utilized to tune the sign of the Casimir force between dielectric substrates as well as its magnitude across a striking range spanning several decades. We also report on a peculiar cancellation of the contributions from nonzero Matsubara modes deep into the retarded range of distances; an effect that can be interpreted as an emergent classical limit where the built-in quantum relativistic signature of the Casimir effect is effectively ‘switched off’.