Today's question comes from my best friend and former college roommate, Dennis. Dennis is actually better suited to write these Wednesday posts as he's wicked smart and reads all sort of science stuff in his spare time while I read Playboy and play with Legos. Oh well, I guess you get what you pay for.
His question is:
Can I hit a ping-pong ball hard enough to barrier tunnel through my opponent's paddle (the Guile sonic boom principle)?Ah, Guile, he of the massive flattop and annoying turtling moves. Was there no more annoying opponent in Street Fighter? That Sonic Boom attack followed up with a flying high kick and then he fucking crouches down and keeps hitting you with that stupid light punch, charging up the whole time. Bastard!
Barrier tunneling is an interesting quantum mechanical phenomenon by which particles "tunnel" through energy barriers. It's actually more complicated than that, and as such, requires a bit of an explanation. Lucky for you, I'm just the guy to provide it.
Lets say you have a boulder, and you want to roll the boulder up a hill of a certain height. I don't know why, it's not important there Sisyphus, just roll the damn boulder. As you roll the boulder up the hill, the kinetic energy of the moving boulder gets turned into potential energy. Once you get to the top of the hill, if there's some kinetic energy left over, the boulder will roll right down the other side. If, there isn't enough kinetic energy, the boulder either stays at the top, never to move again, or rolls back down the side you're pushing it up, crushing you to death in the process. Rough stuff, this boulder.
Now, let's say instead of a boulder, you have a particle, like an electron. It's moving along and it comes to an energy barrier of certain height. Now, just like our boulder, if the energy is enough to get over the barrier, than yay for it, and it moves along it's way. If, on the other hand, the particle has far less energy than what's needed to cross the barrier, it's repelled from the barrier. If the particle though has just a little less energy than what's needed, it tunnels through the barrier. This is because, quantum mechanically speaking, the particle isn't a boulder, it's a wave, and the wave function that describes the particle's behaviour extends through the barrier, and comes out the other side, albeit diminished. As the wave function describes all the possible positions of a particle, a dimished wave function on the other side of the barrier means that there's a small probability that the particle will end up on the other side of the barrier. As there are no available states in the barrier for the particle to exist in, our particle can't end up in the barrier, like our boulder can end up at the top of the hill.
Now, we say that there's a small probability that tunneling will take place, but even a small probability spread out over the billions and billions of particles that make up our magnificent world means that it happens enough for us take advantage of it and use it for our nefarious purposes. A variation of quantum tunneling called the Fields Effect acts as an electron source for flash memory. Quantum tunneling also allows for scanning tunneling microscopes to exist, which helps us witness surfaces at an atomic scale, and build messages like IBM roxors! made entirely out of atoms. Oh those wacky IBM guys.
Now, on to your question Dennis. Yes, there is a probability that every single particle in the ping pong ball could barrier tunnel through the near infinite number of energy barriers that exist in your opponent's paddle, thereby passing the ball through the paddle and signifying you as the Gnip Gnop God of the ages, however the probability is so small, that you could hit ping pong balls until this universe were reduced to dust and never have it happen. Better you just work on a devastating cross shot and be done with it.
I should say, that prior to the cinematic masterpiece that was "Street Fighter", I would have put the aforementioned probability right up there with the odds that renouned actor Raul Julia's last role before his untimely death would be starring across Jean-Claude Van Damme in a movie based on an arcade fighting game. Goes to show you how much I know.
I think we'll continue this quantum train next week and talk about why quantum computers are soooooo much better than regular computers, except for the fact that they don't exist yet.
Wikipedia - Quantum Tunneling
PhysicsPost.com - Understanding Quantum Tunneling
Wikipedia - Field Emission
Wikipedia - Scanning Tunneling Microscope