To reduce the frequency of a particle when it behaves like a wave, we need to ...

-Increase its mass
-Reduce its speed
-Increase its speed
-Hit it with low energy photons
-Hit it with high energy photons

Does the same wave theory apply? i.e. V = f(lambda)

4 answers

When speaking of the wave velocity of a a particle, you have to distinguish between the group velocity of the "wave packet" of waves of different frequencies (which tends to move with the particle while spreading out due to the uncertainty principle) and the "phase velocity" of the different waves that make up the wave packet. The phase velocity exceeds the speed of light. A particles can be thought of as a wave packet consisting of "beats" in its Be Broglie waves.

The formula V = f(lambda) only applies if V is the phase velocity, not the particle velocity.

You CAN use the rule
h*frequency = energy
which implies that you have to increase the energy and the speed of the particle, in order to increase its wave frequency.

For a better explanation, see
http://en.wikipedia.org/wiki/Phase_velocity
So the best answer would be increasing the speed, rightÉ
Yes. While I'm at it, I misspelled De Broglie in my previous answer.
I thought to reduce the frequency of a particle, you would have to decrease the speed. no?