# Why do matter waves have superluminal phase velocites?

Specifically why do they have $$V = \frac{c}{β}$$ as stated in this paper written by De Broglie: http://aflb.ensmp.fr/LDB-oeuvres/De_Broglie_Kracklauer.pdf ?

I follow the proof of “phase harmony” between the reference frames, but i’m getting confused between them and i don’t see why $$V = \frac{c}{β}$$

P.S i know matter waves are kind of an archaic concept, this is purely a historical exercise.

• – Qmechanic Apr 1 '20 at 16:42
• Matter waves are not an “archaic concept”. They have been an experimental reality for a century. – G. Smith Apr 1 '20 at 17:11