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Particles with nonlinear electric response: Suppressing van der Waals forces by an external field
Heino Soo1,2, David S Dean3, Matthias Krüger1,2
14th Institute for Theoretical Physics, Universität Stuttgart, D-70569 Stuttgart, Germany.
Physical Review. E
|February 18, 2017
Summary
We investigated Casimir forces between particles with anharmonic dipoles under electric fields. The force can be tuned to near-zero values by adjusting the electric field strength and orientation.
Area of Science:
- Condensed matter physics
- Quantum field theory
- Electromagnetism
Background:
- Casimir forces, also known as van der Waals forces, arise from quantum fluctuations.
- These forces are significant at microscopic scales and influence the behavior of materials.
Purpose of the Study:
- To investigate the classical thermal component of Casimir forces between point particles with anharmonic dipole Hamiltonians.
- To analyze the influence of external electric fields on these forces.
- To explore methods for tuning and suppressing Casimir forces.
Main Methods:
- Analytical calculations were performed on a model system.
- The model features individual dipole moments that saturate in strong external electric fields, mimicking neutral, perfectly conducting spheres.
- Comparison with harmonic dipole Hamiltonians was conducted.
Main Results:
- The Casimir force is strongly dependent on the external electric field strength.
- For a specific orientation of the external field relative to the particle axis, the fluctuation force can be suppressed to arbitrarily small values.
- A simple formula for asymptotically large external fields was derived for saturating dipole moments.
Conclusions:
- External electric fields offer a powerful means to control Casimir forces.
- Anharmonic dipole models with saturating moments exhibit unique field-dependent force characteristics.
- The findings provide insights into manipulating inter-particle forces in various physical systems.
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