Everyday physics: pressure cookers.

Most graduate students out there can at times feel a lot pressure to perform. Heck, that is not just graduate students. Pressure at work seems to be one of those things that most people can relate to and feel all the time. It gives rise to a lot of stress. I don’t have any good recipe for combating stress that is guaranteed, but cooking sometimes helps. Seeing as what I just wrote is not too funny, maybe I should get to the point and talk about Pressure cookers and as a bonus you get a cooking recipe (no peeking). When in doubt, pick a gadget and explain it, yes sireee. Besides, the explanations that I found on the internet about how pressure cookers work teeter on the edge of crackpottery. Not all are bad, but most don’t really say anything other than water boils at higher temperature at higher pressure which is correct, but unsatisfying. It’s like saying it just works that way.

My 3d rendition of a pressure cooker

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Particles from fields

This is the third part of a series of posts introducing the basics of quantum field theory, previous installments are here (part 1) and here (part 2).

Suppose we have a continuous medium, an elastic band or the surface of a pond, we can then have traveling waves propagating in the medium. Just throw a stone into a calm pond and observe those waves. As long as the equations governing the medium are linear, we can superpose solutions and create pulses: localized bundles of energy which look a lot like particles, almost. So, it looks like we can throw away the problematic point particle, replacing it by a special kind of field, the one that obeys linear equations. Those are called linear fields, or free fields. However, we are not yet there…

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