What is Casimir force: Definition and 16 Discussions

In quantum field theory, the Casimir effect is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of the field. It is named after the Dutch physicist Hendrik Casimir, who predicted the effect for electromagnetic systems in 1948.
In the same year, Casimir together with Dirk Polder described a similar effect experienced by a neutral atom in the vicinity of a macroscopic interface which is referred to as Casimir–Polder force. Their result is a generalization of the London–van der Waals force and includes retardation due to the finite speed of light. Since the fundamental principles leading to the London–van der Waals force, the Casimir and the Casimir–Polder force, respectively, can be formulated on the same footing, the distinction in nomenclature nowadays serves a historical purpose mostly and usually refers to the different physical setups.
It was not until 1997 that a direct experiment by S. Lamoreaux quantitatively measured the Casimir force to within 5% of the value predicted by the theory.The Casimir effect can be understood by the idea that the presence of macroscopic material interfaces, such as conducting metals and dielectrics, alters the vacuum expectation value of the energy of the second-quantized electromagnetic field. Since the value of this energy depends on the shapes and positions of the materials, the Casimir effect manifests itself as a force between such objects.
Any medium supporting oscillations has an analogue of the Casimir effect. For example, beads on a string as well as plates submerged in turbulent water or gas illustrate the Casimir force.
In modern theoretical physics, the Casimir effect plays an important role in the chiral bag model of the nucleon; in applied physics it is significant in some aspects of emerging microtechnologies and nanotechnologies.

View More On Wikipedia.org
  1. peterbb

    A In light of new evidence, what might be behind the Casimir Effect?

    (note to mod: I changed the journal to a more reputable one that should fit the rules - please check if it's approved for you - thanks!) Preface Some of you may know this but a little while ago Garret Moddel, a professor at Boulder Colorado University, published a paper that described an...
  2. S

    I "Breaking the loop" in Casimir force?

    The Casimir force involves a complicated interaction between electrons in one plate, the electromagnetic field in the gap, and the electrons in the other plate. In this process, it makes no sense to talk of cause and effect, since all entities affect each other all the time. Would it make sense...
  3. S

    I Casimir force and the Vacuum Field

    The Casimir force is often explained in connection with the zero point energy of the quantized EM field, and the fact(?) that metal boundaries modify this spectrum in such a way that a force is created. However, other sources (including some discussions on this forum) say that this is not the...
  4. S

    I Poles in Casimir force as function of frequency & mode

    In Numerical methods for computing Casimir interactions, we have this expression for the Casimir force between two plates: where I am trying to interpret this physically on a per-frequency and per-mode basis, before actually looking at the complete integral. If we focus on a single...
  5. C

    I In the Casimir effect, can you slide plates unopposed by force?

    How would sliding the plates parallel to each other in order to separate them (they are prevented from contacting to avoid friction) require the same amount of energy as pulling them apart? You're not pushing against the force (the net force at the edges pulling it back is balanced by opposite...
  6. pchu

    Casimir force experiments under environmental EM noises?

    I've always been curious about how rigorous are the Casimir force measurements carried out, because a couple of years ago I read some news about people inventing perpetual motion machine which turned out to be draining power from environmental EM noises, say, radio station, wifi, 3G/4G that keep...
  7. M

    Where can I get Casimir plates?

    Where can I find actual Casimir plates? To buy or hire for experiments, I mean. If so, what do they cost?
  8. A

    Casimir Force for a Trapped Bose Gas in d-dimension

    Currently found a paper which calculates Casimir Force of a trapped Bose gas in d-dimension. But what is the use of calculating Casimir Force of a Bose gas greater than 3 dimension? Any example where this calculation might be helpful?
  9. G

    Can Different Dielectric Values Affect the Distribution of the Casimir Force?

    So I was reading an excerpt from Lifshitz about the Casimir effect, and besides the obvious dependency on plate separation and geometry, he indicated that the strength of the force also depends on the dielectric value of the plates. What I'm wondering is what the force distribution for the...
  10. M

    Calculate Casimir force between several plates

    Hello I want to ask how to calculate the force change if it has been used several plates adjacent to the Casimir effect. for example - | | | | | | | | | - gap between the plates is 20 * 10 ^ -9 m. Between the plates is a vacuum? Thank you. Goodbye.
  11. K

    Simple derivation of Casimir Force

    Homework Statement Derive the Casimir Force on each plate, for a two parallel plate system (L x L), separated at a distance of 'a' apart. The solution was found in en.wikipedia.org/wiki/Casimir_effect#Derivation_of_Casimir_effect_assuming_zeta-regularization. (sorry I couldn't include link...
  12. J

    Generating Electricity with Casimir Force and Piezo-Electric Material

    could you generate electricity by occilating a peizo-electric material by the use of the casimir force between two metal plates? As the plates squeeze or strain the material (via casimir effect), the material would resist the squeezing or straining (due to hooke's law), and would resist to a...
  13. S

    Casimir force and cavity radiation.

    I tried to calculate the casimir force. I need to know if the way I doing it is correct. So I note some steps: 1. I calculate the energy in the space without the plates 2. I calculate the energy between the two plates And then I speculated. I thougt of taking the difference of one and two...
  14. marcus

    Is the Casimir Effect Evidence of Dark Energy or Vacuum Energy in Cosmology?

    http://arxiv.org/hep-th/0503158 The Casimir Effect and the Quantum Vacuum R. L. Jaffe 9 pages, 3 figures "In discussions of the cosmological constant, the Casimir effect is often invoked as decisive evidence that the zero point energies of quantum fields are 'real'. On the contrary...
  15. A

    Exact mechanism of Casimir force

    Do we actually know exactly how the Casimir force is produced, or is this still something to be researched? I know the plates block out some of the vacuum flactuations modes, so the "pressure" outside the plates is more than the "pressure" inside the plates. But how does this "pressure" form? Is...
  16. marcus

    How does the Casimir force work?

    How do you imagine the Casimir force working? By what mechanism does it arise, as you picture it? If you had two square plates each 1.6 meters (5 feet) on a side and you could position them side by side almost touching but with say 1/60 of a millimeter gap, by what force would they attract...