Are van der Waals forces the fundamental basis for the Casimir effect?

In summary, the Casimir effect is a phenomenon explained by the quantized field and described with QED. It is believed to be the cause of van der Waals forces. However, some theories suggest that an accurate solution to the Schrödinger equation without a quantized field can also result in van der Waals forces, which is a key issue in DFT. It is assumed that this approximation is only an approximation, and the question remains about how accurate it truly is. Additionally, van der Waals forces are considered fundamental, and the Casimir effect is a result of them.
  • #1
alxm
Science Advisor
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As I understand it, the Casimir effect is due to the quantized field, and can only be described with QED.
Also, van der Waals forces are supposedly a result of the Casimir effect.

Here's what I don't understand. Supposedly, an accurate solution to the Schrödinger equation - without a quantized field, but rather with instantaneous coulomb forces, does give vdW forces as a long-range electron correlation effect. (This is a important problem in DFT, where most correlation functionals are local and do not reproduce vdW effects)

Would someone more versed in QED care to reconcile this for me?
My working assumption is that that vdW forces are reproduced, but only approximately, with 'c=infinity' then. In which case I'm wondering: How good is that approximation?
 
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  • #2
alxm said:
Also, van der Waals forces are supposedly a result of the Casimir effect.
It's the other way around, van der Waals forces are fundamental and Casimir effect results from them. See e.g. https://arxiv.org/abs/1702.03291
 

1. What is the Casimir effect?

The Casimir effect is a physical phenomenon in which two uncharged objects in close proximity experience an attractive force due to the presence of quantum fluctuations in the vacuum. This force is a result of the objects limiting the number of possible wavelengths of these fluctuations, leading to a net force between them.

2. What are van der Waals (vdW) forces?

Van der Waals forces are weak attractive forces that exist between molecules or nonpolar atoms. These forces are caused by temporary dipoles that form in the electron clouds of these particles, resulting in an attraction between them.

3. How do the Casimir effect and vdW forces differ?

The Casimir effect is a macroscopic phenomenon that arises from quantum mechanical principles, while vdW forces are a result of the interaction between molecules on a microscopic scale. The strength of the Casimir effect is dependent on the geometry and distance between objects, while vdW forces are dependent on the types of molecules involved.

4. Can the Casimir effect and vdW forces be observed in everyday life?

Yes, both the Casimir effect and vdW forces play a role in many everyday phenomena. For example, the Casimir effect is responsible for the adhesion between two smooth surfaces, such as the pages of a book. VdW forces are also present in many biological systems, such as the interaction between enzymes and substrates.

5. How do scientists use the Casimir effect and vdW forces in research and technology?

Scientists use the Casimir effect and vdW forces in a variety of research fields, such as nanotechnology and material science. These forces can be harnessed to manipulate and control the behavior of particles on a small scale, leading to advancements in areas such as energy storage and drug delivery systems.

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