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ENS Cachan - Laboratoire de photonique quantique et moléculaire

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Abstract Ulf Leonhard

Geometric regularisation of the Casimir force.

Ulf Leonhardt (Institut Weizmann, Israël)

The lecture discusses forces of the quantum vacuum, which may sound like an arcane subject, but it is not - such forces are acting all around us and play a major role in daily live and modern technology, but most people are simply not aware of them.
According to quantum physics, the vacuum is not simply a desert of emptiness and nothing, but a sea of possibilities. The fluctuations of the quantum vacuum play a similar role credit plays in economy: they make things possible by borrowing. For example, the quantum vacuum may lend a dipole moment to an atom (a deformation of its electric charge distribution) and then this atom interacts with other atoms around it, attracting them. The dipole moment disappears, the credit from the quantum vacuum is paid back, but the attraction remains. This attraction between neutral atoms and molecules is responsible for most of the stickiness in Nature, and it becomes an issue for nano-machinery where it causes friction.
The lecture describes how ideas from geometry can be applied in the regularisation of vacuum forces.