Quantum mechanics
From RationalWiki
This article is only a brief description of the subject, and is not intended to give a full explanation.
Check out the "see also" or "references" sections, or Wikipedia's article for more detail.
| “ | I think I can safely say that nobody understands quantum mechanics. | ” |
| —Richard Feynman, in The Character of Physical Law (1965) | ||
Quantum mechanics (QM) is a branch of physics developed to deal with sub-atomic particles and their interactions. Most of the foundations of QM were formulated during the first three decades of the 20th century. Modern quantum physics has advanced considerably, and is used extensively in the study of chemistry and materials, including biological research, and in cosmology and astronomy.
One of the awesome things quantum mechanics explains is why energy is absorbed or emitted by atoms only in discrete amounts, or "quanta". This in turn explains why hot objects (like the sun) shed light in the specific way that they do. Quantum mechanics also explains a host of other phenomena, like superconductivity (used in MRI machines and some high-speed trains), Hawking radiation (theoretically emitted by black holes), the fine structure of the microwave background cosmic radiation (caused by quantum fluctuations on top of flat spacetime), how magnets work, the biochemical properties of proteins, why metals conduct and plastic doesn't, and more.
Quantum mechanics is a way of constructing theories rather than a single theory about reality. The most developed quantum theory to date is known as the "standard model", and is considered to be the most accurate physical theory ever created. It has been proved to be valid to a very high precision. However, the standard model does not take gravity into account, and it is believed a more general "Theory of Everything" would be required to incorporate it. Although it isn't clear how, most researchers believe that this theory, too, would be a quantum theory.
Quantum mechanics was described by Albert Einstein as "spooky" because, at the sub-atomic level, physics as we know it breaks down and becomes almost incomprehensible. Just do a internet search on "quantum entanglement" and you'll see what he meant.
[edit] See also
- Quantum physics terms
- Sham quantum physics
- Quantum electrodynamics
- Quantum chromodynamics
- Relativity - not closely related to quantum mechanics, but a lot of people lump them together.
