Effect of Spatial Inhomogeneity on Quantum Trapping

Abstract

An object that is immersed in a fluid and approaching a substrate may find a potential energy minimum at a certain distance due to the balance between attractive and repulsive Casimir–Lifshitz forces, a phenomenon referred to as quantum trapping. This equilibrium depends on the relative values of the dielectric functions of the materials involved. Herein, we study quantum trapping effects in planar nanocomposite materials and demonstrate that they are strongly dependent on the characteristics of the spatial inhomogeneity. As a model case, we consider spherical particles embedded in an otherwise homogeneous material. We propose an effective medium approximation that accounts for the effect of inclusions and find that an unprecedented and counterintuitive intense repulsive Casimir–Lifshitz force arises as a result of the strong optical scattering and absorption size-dependent resonances caused by their presence. Our results imply that the proper analysis of quantum trapping effects requires comprehensive knowledge and a detailed description of the potential inhomogeneity (caused by imperfections, pores, inclusions, and density variations) present in the materials involved.

Casimir‐Lifshitz Optical Resonators: A New Platform for Exploring Physics at the Nanoscale

“…[103] Other approaches consider the use of hyperbolic, [104,105] chiral, [106,107] magnetic, [108] magnetodielectric, [109] or 2D materials [110,111] like the graphene family, [112][113][114][115] as well as the mixing of various materials in finite multilayer architectures, [116][117][118][119][120] or composites. [121][122][123] On the road to quantitative determine F C − L , several outstanding technological approaches have been explored. These include, as previously mentioned, the use of a micromechanical torsional oscillator or a cantilever, [124] even for a three-body system.…”

Modeling Weakly Scattering Random Media: A Tool to Resolve the Internal Structure of Nanoporous Materials

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Physical Limit of Nonlinear Brownian Oscillators in Quantum Trap

“…For a flat Au plate far away from the Teflon−ethanol interface (w/h e < 1), the Stokes law is suitable, 52 = R 6 Stokes e , where R e is the effective radius of square plate and η is the kinetic viscosity of ethanol. If h e is small compared with w, the pressure drug contributed by the confined liquid is significant and shall be described by the squeeze film damping (SQF) model, 48 = R h 6 /4 SQF e 4 3 . Consequently, the damping and random forces diverging with reducing separation set another limit on the lowest effective damping ratio.…”

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