Quantum Weirdness: Why bother?

This week, we take a look at some of the strange behaviors in the universe that arise because of quantum mechanics. If you've studied physics for more than a semester, or have watched any physics documentaries on TV, you've probably heard of quantum mechanics and its two types of weird behavior, which apply in the world of very small particles or very cold temperatures:

• Physics properties that we, in the everyday world, think of as smoothly varying (most notably, energy) occur in discrete lumps (or "quanta"--hence the name "quantum mechanics"):

  

  Image credit: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/imgqua/hosc9.gif
• Physics properties that we, in the everyday world, think of as well-defined and localized (most notably, position and momentum) are actually spread out or "fuzzy:"

  

  Image credit: http://upload.wikimedia.org/wikipedia/commons/9/90/QuantumHarmonicOscillatorAnimation.gif

I emphasize that quantum mechanics is different from the "everyday world" because you and I, as beings made of many many particles at very high temperatures, do not notice these effects in our experiences. This raises the question of why we should bother studying quantum mechanics at all, if it doesn't relate to "the real world."

The Royal Society has a wonderful brief answer to this question, pointing out that studying quantum mechanics gives us...

• A better understanding of chemistry.
• A basis for working with radioactivity.
• The laser!
• The physical mechanism by which our eyes work.
• Digital cameras.
• Scanning tunneling microscopes.
• Encryption (coming soon!).
• Quantum computing (coming soon!).

This week, we'll look more deeply at the technological applications of quantum mechanics to continue to answer this question.