# Single photon absorbed by single atom antenna

1. Feb 11, 2016

### jaydnul

If I shot a 5khz photon at a theoretical antenna made of one copper atom, the electron would absorb the photon and gain energy. What is it about that boost in energy that makes the electron oscillate at 5khz in the direction perpendicular to the photon's direction of propagation?

2. Feb 11, 2016

### Staff: Mentor

If you have a single copper atom, then you don't have an antenna, nor will you have an electron oscillation at the frequency of the photon. The atom (nucleus + electrons) will absorb the energy of the photon, which is related to its frequency by $E = h \nu$.

'if you want to understand antennas, a classical picture is best (classical EM wave + classical motion of conduction electrons in a metal). Collective behavior canot be reduced to the behavior of individual particles.

3. Feb 11, 2016

### jaydnul

I'm not looking for a better working model of how antennas work, I'm just curious.

Even if you have a classical electromagnetic wave, it can only ever interact/transfer energy through quantized bits (photons). So I'm asking about the correspondence principle; how do the individual photon-electron interactions add up to produce the collective motion in the axis perpendicular to the direction the EM wave is traveling?

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