Saturday, August 14, 2010

Meeting Summary 13th of August

Here is a summary of the things we talked about in our meeting on Friday. Unfortunately my notes are not in chronological order, so the notes probably won’t reflect the order you remember things from the meeting.

We started off by discussing assignment question 3.2, which lead into a discussion about the Boltzmann distribution. In the Boltzmann distribution, the statistic E/kbt is sufficient to describe the distribution. This means knowing the statistic, such as the average kinetic energy of the particles in a room, means knowing everything about the distribution of that statistic.

If a distribution requires another statistic to describe the distribution, then the second statistic is a second moment. The second moment is usually the variance. A Gaussian distribution has a second moment since it depends on the statistic (x-mu)^2/sigma^2, where mu is the average value and sigma is the variance. A distribution can have more moments, like a measure of the symmetry about the mean.

We compared classical and quantum mechanics, and discussed the classical uncertainty principle. The Schrödinger equation can be derived from information theory. Quantum mechanics looks like classical mechanics but with probabilistic objects rather than definite ones.

We discussed the feasibility and flaws in ‘black box’ thought experiments (as described in section 3.2.2), and performing them in reality.

We discussed what it might feel like to experience no external pressure, and consequently what space would feel like. The Russian cosmonaut in-training who experienced very low pressures was mentioned. The episode of Mythbusters which tested whether a diver using an old time diving suit would be crushed into his helmet if the tube which equalised the pressure was blocked, was brought up also.

Finally we discussed the information entropy of a DNA nucleotide, and if the heat produced by a computer was due to the loss and gain of information entropy. This also lead to a discussion of optical computers.

It was confirmed that we are having an exam at the end of the semester, and the meeting next week will be at the normal time, for 2 hours again.

1. Turns out the space suit tester was an American: http://www.youtube.com/watch?v=KO8L9tKR4CY

2. Hi Mitch,
thanks for the summary. sorry i could not make the meeting.

Could someone clarify the following?

"We compared classical and quantum mechanics, and discussed the classical uncertainty principle. The Schrödinger equation can be derived from information theory. Quantum mechanics looks like classical mechanics but with probabilistic objects rather than definite ones."

is that the quantum Heisenberg uncertainty principle?

i am unaware of any derivations of the schrodinger equation.

3. Here's a quick view of the mythbusters diving helmet: http://www.youtube.com/watch?v=_ayLaYzW6P0

It seems 135 pounds of pressure per square inch is more than enough to crush someone into their helmet.