Notes on Some Entanglement Properties of Quantum Field Theory · HackerPapers discussions

Notes on Some Entanglement Properties of Quantum Field Theory — mentioned by zachf

Sat, 26 Mar 2022 17:43:15 GMT

I can see why it might look like that from the outside, but the set of mathematical results that led up to it actually come from the angle of, “let’s try to prove that traversable wormholes and the negative energy densities required to create them are impossible.” In trying to prove that, you learn a lot of interesting things along the way: 1. Negative energy densities are a universal prediction of all quantum field theories, and therefore are not as outrageous to think about as one might naively believe. [0] 2. The amount of negative energy density permitted by quantum field theory is NOT…

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Notes on Some Entanglement Properties of Quantum Field Theory — mentioned by zachf

Wed, 30 Dec 2020 23:11:34 GMT

Good question! You can definitely add a constant to the Hamiltonian without changing the local physics, but I was referring to the stress-energy tensor (i.e. energy density), not the Hamiltonian (total energy). The stress tensor can be locally negative but still integrate to a positive or zero value of total energy. So let's talk about energy density, I'll call it T. I need two facts: 1. The Reeh-Schlieder theorem implies that any operator that the vacuum state of QFT is "separating", meaning that the only operator A that satisfies A|0> = 0 is the trivial solution A = 0. (Here |0> means…

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