VERIFICATION OF THE EXISTENCE OF MACROSCALE REPULSIVE CASIMIR FORCES IN SUSPENDED SELF-STANDING FILMS.

THE ULTIMATE GOAL OF THE VERSUS PROJECT IS THE FIRST OBSERVATION OF REPULSIVE CASIMIR-LIFSHITZ FORCES IN MACROSCOPIC PLANE-PARALLEL SYSTEMS. TO THIS END, IT WILL FOCUS ON THE DESIGN, FABRICATION, AND CHARACTERIZATION OF OPTICAL MATERIALS THAT ALLOW CONTROLLING THE INTENSITY AND NATURE OF THE CASIMIR-LIFSHITZ FORCE, SO THAT LEVITATION PHENOMENA CAN BE OBSERVED AND CHARACTERIZED DUE TO THE BALANCE BETWEEN THE LATTER AND GRAVITY FORCE. THIS RADICALLY NEW APPROACH MAKES USE OF OPTICAL SPECTROSCOPIC TECHNIQUES (BASED ON OPTICAL INTERFEROMETRY BETWEEN THE PARTIALLY REFLECTED AND TRANSMITTED LIGHT AT THE INTERFACES OF THE PLANE-PARALLEL SYSTEM) FOR CHARACTERIZING THE EQUILIBRIUM DISTANCE AT WHICH THE SYSTEM LEVITATES OVER A SUBSTRATE. ACCORDING TO VERY RECENT RESULTS ATTAINED BY THE APPLICANT GROUP, IT IS POSSIBLE TO FIND MATERIALS WHOSE OPTICAL CONSTANTS AND DENSITIES ARE SUCH THAT WHEN THEY ARE IMMERSED IN A FLUID THEY CAN LEVITATE OVER A SUBSTRATE AS A RESULT OF THE AFOREMENTIONED FORCE BALANCE. OUR GROUP HAS RECENTLY DEMONSTRATED THEORETICALLY THAT THERE IS A NUMBER OF MATERIALS THAT PREPARED IN THIN FILMS (< 1 MICROMETER) CAN LEVITATE SEVERAL TENS OR HUNDREDS OF NANOMETERS OVER A CAREFULLY SELECTED SUBSTRATE. SPECIFICALLY, THIN LAYERS MADE OF TEFLON, POLYSTYRENE OR SILICON DIOXIDE IMMERSED IN GLYCEROL ARE EXPECTED TO LEVITATE OVER A SILICON WAFER, BEING POSSIBLE TO TUNE THE EQUILIBRIUM DISTANCES AT WHICH SUCH LAYERS WILL BE SUSPENDED THROUGH THEIR THICKNESSES AND TEMPERATURE OF THE SYSTEM. THE DEVISED SELF-STANDING THIN FILMS (IN SINGLE LAYERS OR MULTILAYER ARRANGEMENTS) MUST BE COMPACT, MECHANICALLY STABLE, OF SMOOTH SURFACES, OF CONTROLLED THICKNESS, AND CHEMICALLY COMPATIBLE WITH THE FLUID IN WHICH THEY ARE IMMERSED. THE MACROSCOPIC OBSERVATION OF REPULSIVE CASIMIR-LIFSHITZ FORCES, NEVER REPORTED BEFORE, THROUGH OPTICAL SPECTROSCOPIC MEASUREMENTS WOULD CONSTITUTE AN UNPRECEDENTED MILESTONE IN THE FIELD OF FUNDAMENTAL MATTER INTERACTIONS.