In physics research, keeping atoms at a standstill is a very difficult proposition, but it produces a state which is extremely handy for research into atomic physics. If an atom is moving when particles are shot at it, it becomes difficult to get insight into the collision as the movement leads to Doppler effects that make the results very hard to interpret.
Normally, atoms are held in one spot by physicists via force fields of lasers and magnetic fields; however these cause problems when beams of electrons or ions are thrown into the mix. This means that the magnetic field must be switched off right before the collision is to take place, and it can take up to 20 milliseconds for the magnetic fields to come to a standstill themselves – by that time the atoms are moving around already.
Enter Andrew Murray’s guitar rig. Andrew is a physicist at the University of Manchester, UK and also a rock guitar player. He has managed to perform a trick using his amp and speaker coils from a high-powered speaker system that has eluded big-budget science for decades.
Unlike the normal coils that physicists have been using to keep atoms still, speaker coils use alternating current as opposed to direct current. When fed with a sine wave, the speaker coils cycle nicely between a positive and negative magnetic field. At the end of each cycle, the positive and negative currents in the coil cancel each other out to produce a neutral magnetic field.
When the power is cut from the amplifier at the precise moment of the end of a cycle, then the atom is held completely still.
“The alternating [magnetic] field can be used to trap atoms as long as we ensure that the laser beams change polarization along with it,” says Andrew. “We can switch the fields off about 300 to 500 times faster [than before].” That’s fast enough to ensure that the atoms have not had time to escape the trap when they are zapped with an electron beam.
Of course when I heard about this, I realy wanted to hear what he was playing through the speakers to keep the atom still (Chip Meditation 1 would be the absolute PERFECT thing to be playing – very highly recommended by the way), but alas it operates in a vacuum so of course no actual sound is produced.
Murray’s research team is using the device to study the high-energy collisions that are a result of cosmic rays in the Earth’s upper atmosphere.
Here’s to music gear solving major physics problems.
