The quantum harmonic oscillator is the quantum mechanical analogue of the classical harmonic oscillator. It is one of the most important model systems in quantum mechanics because, as in classical mechanics, a wide variety of physical situations can be reduced to it either exactly or approximately. In particular, a system near an equilibrium configuration can often be described in terms of one or more harmonic oscillators. Furthermore, it is one of the few quantum mechanical systems for which a simple exact solution is known. But I'm sure you already knew that, because that's just common sense, which happens to be the sociological ability of humans to recongnize something deemed obvious and therefore point it out to those who don't seem to understand the obviousness of it, obviously.
edit Common sense and You
Lawyers will sue anybody for anything, as long as they get a profit. Did you see a car accident on the side of the road? You can sue them for mental distress! Drop your toothbrush in the bathroom? Sue the toothbrush company for making uneasily gripped toothbrushes! This may seem silly, but it's all true, child. That's because lawyers and common sense work for opposite sides. Remember this the next time you get obese off of fast food. You can sue McDonalds!
edit Politicians vs. common sense
Why would we want a law passed that forbids us from marrying the one we love most? We wouldn't! But politicians would! And here in the good old U.S. of A, common sense takes a back seat with the better good of the people to the intent of politicians. Luckily for you (if you're a lobbyist with millions of dollars for bribery) you can sway the politicians. Some people disagree with this. That's because they have common sense!
edit The Ancient Greeks vs. common sense
Come on, who actually believes some gigantic goddess did it with her brother, the king of all gods, and made some divine beautiful deity? That's incestual and just plain implausible. Ancient people were horny bastards.
edit But what about uncommon sense?
Now you're just being a smartass. Shut up.
edit You vs. common sense
Yeah, you bitch.
edit Great moments in the history of common sense
1214- People of England force super-douche king John to sign the Magna Carta forbidding excessive taxing and tyranny on the part of the monarchy, John has enough common sense to sign the damn thing as to prevent uprising/democracy. Moral win for the peasantry, actual win for the British monarchy. Sorry gang!
1492- Columbus says the earth is not flat, but instead round. Spanish monarchy disagrees, Columbus says "Up yours" and sails to North America, convinces world it's China and that the earth is round. Gets all the ladies upon return to Spain. SIDE NOTE: Columbus was a pimp.
1645- English catholics oppressed by the dominating protestant society just flat out leave and go to America. Irony ensues when they realize they are technically protesting, therefore making them "protest-ants". LOL!
1770's- Colonies decide a taxes on tea and paper are bogus, rebel against the English and become world's greatest superpower. USA! USA! USA! SIDE NOTE: This is before all Americans became self-rightous douche bags.
1970's- Doctors discover smoking is bad for you. RUH ROH
2003- We bomb the crap out of Iraq. USA! USA! U- wait, what?
2004- The Re-election of George W. Bush signified the death of common sense. France doesn't care.
2006 - There is a world wide movement to bring back common sense by overthrowing the governments of the world but the people decide to watch television.
edit A lesson in common sense
If something is obvious and other people don't realize that, YOU WIN.