Category Archives: Math

Q: What is quantum teleportation? Why can’t we use it to communicate faster than light?

Physicist: Contrary to its exciting name, quantum teleportation doesn’t involve any physical stuff suddenly disappearing and then reappearing somewhere else.  Instead it’s a cute, clever, technique for transferring an unknown quantum state of one system (usually a single particle) to … Continue reading

Posted in -- By the Physicist, Entropy/Information, Physics, Quantum Theory | 28 Comments

Q: How do lenses that concentrate light not violate the second law of thermodynamics? If you use a magnifying glass to burn ants, aren’t you making a point hotter than the ambient temperature without losing energy?

Physicist: This is a surprisingly subtle question. It certainly impossible to create new energy, but there’s nothing to stop you from piping energy from one place to another (say, by running hot water from a boiler to somewhere else).  The … Continue reading

Posted in -- By the Physicist, Entropy/Information, Physics | 55 Comments

Q: What makes natural logarithms natural? What’s so special about the number e?

Physicist: “e” shows up on its own a lot, and the frequent appearance of the natural log, ““, follows from that.  Almost all of the uses and importance of e and ln are from results in calculus, but those results … Continue reading

Posted in -- By the Physicist, Math | 10 Comments

Q: In an infinite universe, does everything that’s possible have to happen somewhere?

The original question was: Lets say that we determine that an event is physically possible. So that means the probability of that event is greater than zero. Right? So my question is this. Is there any sense in saying that … Continue reading

Posted in -- By the Physicist, Philosophical, Probability | 65 Comments

Q: What are fractional dimensions? Can space have a fractional dimension?

Physicist: There are a couple of different contexts in which the word “dimension” comes up.  In the case of fractals the number of dimensions has to do (this is a little hand-wavy) with the way points in the fractal are … Continue reading

Posted in -- By the Physicist, Math | 14 Comments

Q: How many theorems are there?

Physicist: Every sub-field in math and physics has at least hundreds, and there are hundreds or thousands of sub-fields.  So overall we’ve proven… At least millions? This is one of those things that can’t really have an exact answer, or … Continue reading

Posted in -- By the Physicist, Math, Philosophical | 6 Comments