There is a quirk in the literature on time-energy uncertainty. It might have started as a little sloppiness. But it has grown into an error that seems to have spread…

Read more## What is a superselection rule?

A superselection rule is a special limitation on what is observable in the quantum world. For example, we can never seem to observe interference from the relative phases between a…

Read more## Philosophy and Physics in the Kadison-Singer Conjecture

A promising proof of the so-called Kadison-Singer conjecture was announced yesterday. Mathematicians are excited, because this conjecture is equivalent to a remarkable number of open problems in other fields. And…

Read more## Writing a book on time reversal

So, I’m writing a book on the foundations of time reversal. I’ve decided to bring back the Soul Physics blog to talk about the book as it’s being written, and…

Read more## Beyond the CPT theorem

Virtually all known laws of physics are invariant under the CPT transformation — that is, the combined operations of Charge conjugation (C), Parity or “mirror flipping” (P), and Time reversal…

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