Hi, I was discussing a question with a Ph.D-student at my uni that neither him or the professor were able to answer.(adsbygoogle = window.adsbygoogle || []).push({});

The situation is the following;

Light enters a medium going from i.e. vacuum. We know that the energy of the photons in the vacuum is

[tex]E = h\nu[/tex]

and we have the de broglie formula

[tex]p = \frac{h}{\lambda}[/tex]

The relation [tex]c=\lambda\nu[\tex] tells us that the wavelength [tex]\lambda[\tex] decreases if the speed of light decreases (since frequency is constant). Does the de broglie formula still hold now? In that case, the momentum increases as the wavelength decreases, eventually reaches infinity when the speed of light goes to zero.

In my eyes, this cannot be true, so the de broglie formula cannot hold for reduced speed of light (also remember that when the light goes out of the medium again, the speed and hence the momentum is back to 'normal' again.

If we look at the particle interpretation of light, the photon will probably hit electrons and excite them and quickly send a new photon again. The reduced speed of light might be a consequence of many collisions.

The problem isn't quite clear, but the de broglie formula, does it hold in non-vacuum material?

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# Photons entering a medium

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