Theory of Casimir Forces without the Proximity-Force Approximation.

Area of Science:

• Condensed matter physics
• Quantum field theory

Background:

• Casimir-Lifshitz forces, both attractive and repulsive, are crucial in nanoscale phenomena.
• Previous models often rely on the proximity-force approximation, limiting their applicability.

Purpose of the Study:

• To develop a generalized kinetic approach for calculating Casimir-Lifshitz forces.
• To investigate the role of collective material excitations and temperature effects.
• To compare theoretical results with experimental data and assess model validity.

Main Methods:

• Utilizing a kinetic approach to derive Casimir forces from absorbed power.
• Modeling collective material excitations using relaxation times distributed via a log-normal function.
• Deriving a generalized expression for forces applicable at arbitrary temperatures.

Main Results:

• The kinetic approach successfully yields Casimir forces based on absorbed power.
• A generalized expression for Casimir-Lifshitz forces, incorporating temperature effects, was obtained.
• The model's predictions align with experimental measurements, demonstrating its validity.

Conclusions:

• The developed kinetic model accurately describes attractive and repulsive Casimir-Lifshitz forces.
• The model surpasses the limitations of the proximity-force approximation.
• This work provides a more comprehensive understanding of Casimir forces in various experimental conditions.