Casimir Effect

Presented by

Lukasz Blaszczyk

What is the Casimir Effect?

Predicted in 1948 by Dutch physicist Hendrick Casimir.

Casimir was working on deposits of colloidal suspensions to manufacture cathode ray tubes.

A small attractive force between two uncharged conducting plates.

What is in a Vacuum?

What is left when you take all particles out of a container and lower the temperature to absolute zero.

Quantum mechanics however states that all fields have fluctuations.

Thus energy of a system is not constant but fluctuates around a mean value.

For a perfect vacuum the mean energy is half the energy of a photon.

Casimir Effect

In a classical vacuum any wavelength photon can be created.

According to quantum mechanincs, within a cavity only certain wavelengths can exist.

Integer multiples of half-wavelengths that can fit exactly inside the cavity are amplified.

Casimir Force

1 meter plates separated 1μm (10e-6m)

Force = 1.3e-3 N

1 centimeter plates separated 1μm

Force = 1.3e-7 N

Roughly the weight of a 1mm diameter water dropplet.

At a distance of 1nm the force is equivilent to 1 atmosphere of pressure.

Detecting the Casimir Effect

Marcus Spaarnay in 1958 used two metallica mirrors of aluminum, chronium, and steel to measure the Casimir Effect.

Mirrors had to be flat

Electrically neutral material

Mirrors arranged perfectly parallel

Steve Lamoreaux in 1997 measured Casimir force to within 5% of theoretical expectations using a 4cm plate and 2.5cm sphere.

Umar Mohideen used 200μm sphere on the tip of an Atomic Force Microscope to within 1% of theory.

Reproducing the Big Bang ... (Sort Of)

Experimental evidence of the Casimir effect is given as proof of vacuum energy density.

Shows electromagnetism follows broken symmetry.

If Super-Symmetric fermionic photinos would contribute negitivly, cancel photons, and not produce the Casimir Effect.

Force is significant for Microelectromechanical systems (MEMS).

Applications of Casimir Effect

Has been proven that Casimir Force can cause elements of MEMS to stick together.

Examine nonlinear phenomena of plate oscillations in MEMS.

Casimir Effect used to control motion of MEMS.

References

The Casimir Effect, http://math.ucr.edu/home/baez/physics/Quantum/casimir.html

Of Some Theoretical Significance: Implications of Casimir Effects, http://www.quantumfields.com/casfin.pdf

The Casimir effect: a force from nothing, http://physicsweb.org/article/world/15/9/6

New Developments in the Casimir Effect, http://xxx.lanl.gov/abs/quant-ph/0106045

General information regarding vacuum fluctuations, http://www.quantumfields.com/articles.htm

Frequently Asked Questions About Virtual Particles, http://www.math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html

Lukasz Blaszczyk

2003-09-08T21:15:43