De broglie frequency The de broglie wavelength of matter particle is very low. Does that mean matter is associated with waves of high frequency? If so why can't we detect them? 
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The de broglie wavelength of matter particle is very low. Does that mean matter is associated with waves of high frequency?

Yes, matter is associated with waves of high frequency, BUT the crux is in the verb "associated". The waves are probabiity waves. Please see this last answer of mine here, that shows how the wave nature of particles appears. Individual particle interactions show the particle nature, an accumulation of a number of interactions in the same boundary condition shows the probability distributions have a wave interference pattern. 

If so why can't we detect them?

We do detect them. 
This interference pattern has been seen with molecules also. The wave nature does not mean that individual particles are spread out all over the place like water waves. The wave nature shows up on the quantum mechanical wavefunction $Ψ$, a complex function calculated for the experiment for each particle, and the complex conjugate square  $Ψ^*Ψ$ gives the probability of finding the particle at (x,y,z) and the accumulation shows the wave interference patterns.
