Casimir Effect

The Casimir effect in quantum field theory is small physical forces that arise from a quantized field. It is mainly due to quantum vacuum fluctuations of the electromagnetic field. Hendrik Casimir, a Dutch Physicists, predicted the Casimir Effect.

Casimir Effect can be understood with a typical example of a vacuum in space. According to the modern physics, the vacuum consists of varying electromagnetic waves and it can never be eliminated. It can be compared to a vast ocean of waves that always shows its existence, and it is unstoppable. These waves always possess a package of viable wavelengths thus implying that an empty space consists of a minimum amount of energy. The energy that we can never feel, in spite of presence.


Now consider two mirrors that are placed in a vacuum facing each other. As a result, some of the waves will occupy the space between the mirrors bouncing backward and forward. Once the mirrors are moved closer to each other the longer waves which are present, due to lack of space they may no longer fit in. This is caused when a total amount of energy that is present between the plates will be a bit less compared to the energy that is present somewhere in the vacuum.

The two mirrors are attracted to each other just as 2 objects that are held together by a stretched spring. Until the energy stored in the spring decreases, there exists a movement of two mirrors. Due to this effect, the two mirrors will be attracted to each other, and this effect is termed as Casimir Effect.

Coupled Ground State Energy:

It is one of the suggested possible cause in understanding the Casimir Effect that is based on canonical macroscopic quantum electrodynamics. There may exist a vacuum of a coupled system which detects the properties of an electromagnetic field that will give rise to force. Casimir force is characterized by a property of a coupled system wherein the synergy between the two plates is mediated by the zero-point fields.

Applications of Casimir Forces:

  • Casimir Forces have its broad application in nanotechnology; Specially silicon integrated technology that is based on Casimir oscillators, nanoelectromechanical and Microsystems.

There are few examples that state that the repulsive force that arises between two uncharged objects is due to Casimir effect. This has created interests in the development of applications regarding the advancement of levitating devices.

Practise This Question

What is the pattern of magnetic field around a current carrying conductor?