Category Archives: Entropy/Information

Q: What does a measurement in quantum mechanics do?

Physicist: This is a follow up of this post, that would’ve been too long and meandering with this included.  To sum up that post, a “measurement” is an interaction that exchanges information. In the Copenhagen interpretation, what that measurement does … Continue reading

Posted in -- By the Physicist, Entropy/Information, Philosophical, Physics, Quantum Theory | 14 Comments

Q: What is a “measurement” in quantum mechanics?

Physicist: Any interaction of any kind that conveys information is a form of detection. This question crops up frequently in conjunction with the “Copenhagen interpretation”. The Copenhagen interpretation of quantum mechanics (which comes in a couple different flavors) is generally … Continue reading

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

Q: What is the entropy of nothing?

Mathematician: In physics, entropy relates to the number of states that a system can be in. If a system actually contained absolutely nothing, then (quantum mechanical considerations aside), it would only have one state, and therefore would have 0 entropy … Continue reading

Posted in -- By the Mathematician, Entropy/Information, Philosophical | 8 Comments

Q: How does quantum computing work?

The original question was: Could you give a description of the principles behind quantum computing? And how is it that some problems have a better time-complexity when they’re run on a quantum-computer? Physicist: Particles and sets of particles are frequently … Continue reading

Posted in -- By the Physicist, Computer Science, Engineering, Entropy/Information, Math, Physics, Quantum Theory | 22 Comments

Q: Does the 2nd law of thermodynamics imply that everything must eventually die, regardless of the ultimate fate of the universe?

Physicist: The 2nd law of thermodynamics states that in any closed system entropy will increase over time. The exact rate at which entropy increases is situation dependent (e.g., being on fire or not). As a quick aside, one of my … Continue reading

Posted in -- By the Physicist, Biology, Entropy/Information, Evolution, Paranoia, Philosophical | 9 Comments

Q: What’s so special about the Gaussian distribution (i.e. the normal distribution / bell curve)??

Physicist: A big part of what makes physicists slothful and attractive is a theorem called the “central limit theorem”.  In a nutshell it says that, even if you can’t describe how a single random thing happens, a whole mess of … Continue reading

Posted in -- By the Mathematician, -- By the Physicist, Entropy/Information, Equations, Math, Probability, Quantum Theory | 11 Comments