7 ms·
Quantum Bayesianism
- philipov 10y agoThe article is an announcement of a lecture. I couldn't find a recording of it or any previous physics lectures by him. It looks the only recordings are of him giving religious sermons.
- abrax3141 10y agoA book just came out.
- jerf 10y agoTo those who check the comments before reading, note this article says nothing about what Quantum Bayesianism is. It's an announcement of a presentation and apparently a book, and a sales job on how important the idea is, but has no trace of the idea. I'm not saying there's anything wrong with that per se, but it's probably not what an HN reader is expecting.
- WhitneyLand 10y agoYes but is has some interesting talk about theory vs. meaning, science vs. philosophy, and other aspects of QM interpretations. Btw to address your concern: https://en.m.wikipedia.org/wiki/Quantum_Bayesianism https://en.m.wikipedia.org/wiki/Quantum_Bayesianism
- Strilanc 10y agoCan someone explain what the deal with qbism even is? Like, I get that when you do weak measurements the random walk the qubit takes [2] looks basically identical to inference. That's not too surprising, given how similar the definition of quantum states is to the definition of probability distributions. But superpositions aren't literally probability distributions. In particular, unlike with probabilities, you can prove that super-logical agents can't rationally disagree about the superposition that a state is in. Superpositions can't be observer-dependent in the way that probability distributions can, because you can create situations where agents who are disagreeing about a superposition must be risking the highest of Bayesian sins: seeing something happen to which they assigned a 0% probability [1]. To me, this directly disagrees with Qbism's tendency to think about quantum states as subjective instead of objective. 1: http://www.scottaaronson.com/blog/?p=822 http://www.scottaaronson.com/blog/?p=822 2: http://algorithmicassertions.com/2016/04/24/eves-quantum-clone-computer.html http://algorithmicassertions.com/2016/04/24/eves-quantum-clo...
- n4r9 10y agoI can try to offer something about the tension between the PBR theorem and QBism. I sat through a conference talk by Chris Fuchs not long after PBR came out, although some of the detail will probably be lost in translation. PBR assumes that the quantum state of a system represents a state of ignorance or partial information concerning an objective, underlying (hidden variable) reality. In QBism the quantum state of a system instead represents an agent's beliefs about what will happen in future interactions with the system. There's no mention of an underlying observer-independent reality. It's not assumed that the physical state of a system can be portrayed with objective, observer-independent variables, nor that a given quantum state assigns probabilities to those variables. A cynical summary might be that QBism weasles out of PBR type issues by sticking to radical/subjective Bayesianism, rather than objective Bayesianism.
- ajb 10y agoDoes it require the subjective probability to be complex-valued? (as in eg https://arxiv.org/pdf/hep-th/9307019.pdf https://arxiv.org/pdf/hep-th/9307019.pdf, http://physics.bu.edu/~youssef/quantum/quantum_refs.html http://physics.bu.edu/~youssef/quantum/quantum_refs.html)