Quantum Bayesianism. Down and dirty.

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Quantum Bayesianism. Down and dirty.

In this thread, we cover everything about QBism that you ever wanted to know but were afraid to ask. Get it on the operating table and get bright lights on it and really hammer out the details. I can only give a series of unanswered questions, since I don't have enough time in my real life to research the topic.

My own (likely wrong) understanding of the textbook definition of "Quantum Bayesianism".

QBism.
(n) Defn. An interpretation of QM in which the Schroedinger Wave is measuring the uncertainty in an observer's knowledge of a physical system.

questions:
• Knowledge in a mind is binary. Knowledge allows yes/no questions. But the real world is made of waves that don't fit into binary knowledge/mental architecture. Hence the Schroedinger wave and the peculiar fact that the area underneath the wave is 1.0. (grad students say this is "unitary"). Can/should we tie this into wave collapse?
• Does QBism imply that there are ontic states? Does it require them foundationally?
• The uncertainty in measurement is not 'out there' in nature at all, but is instead contained in the observer?
• Is QBism a clever rehashing of a ..gulp.. hidden variable theory?

hyksos
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hyksos wrote: the Schroedinger Wave is measuring the uncertainty in an observer's knowledge

Let's say that "uncertainty", means absolute uncertainty, rather than mere ignorance. If uncertainty is an inherent part of a physical system, then uncertainty in the mind, about that system, is knowledge.

hyksos wrote:Knowledge in a mind is binary. Knowledge allows yes/no questions.

The uncertainty in measurement is not 'out there' in nature at all, but is instead contained in the observer?

This seems to refer to binary outcomes (e.g. an object is at this location or it is not). In such a situation, terms may be equated: knowledge = measurement = interaction = contact, among others.

"Contact" is the term science has most bungled by failing to recognize interval contact (i.e. contact in 4D). This is largely the result of dogged adherence to the archaic and never-justified spacetime coordinate system (as opposed to interval-time).

Contact is, by definition, mutual. Thus, it entails for example, both object and observer. Contact relates to wave collapse the way putting your finger on a roulette wheel stops it from spinning.

hyksos wrote:Does QBism imply that there are ontic states? Does it require them foundationally? …hidden variable theory?

Hidden contact (that recognizable in 4D but not in 3D) is such a state. More than that, if recognized as an object (a hole, offering potential contact), it qualifies as an "object". It's not so much a question of if they are "required" as that they are undeniable. Thus, it is required that we accept them as real.

Similarly, we must accept that such objects are not constrained by classical laws, and may exhibit instantaneous actions (e.g. chronaxial spin), the very actions which yield the wave nature and its attendant uncertainty.

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Re: Quantum Bayesianism. Down and dirty.

Hyksos, I think my concerns could be similar or shared, and maybe the second point is a good place to begin elaboration. I think the interpretation considers there are pure, subjective states?
dandelion
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Re: Quantum Bayesianism. Down and dirty.

dandelion :
Maybe I should not have asked for anyone's thoughts. Those questions in the bullet-point were what I was going to use to research QBism, if I had enough time in my real life to do so. They are sort of like a little research agenda.

Thanks for participating. This is a QBism thread. Did you have anything to say about QBism?

hyksos
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Re: Subjective Interpretation

hyksos wrote:Those questions in the bullet-point were what I was going to use to research QBism

I mistakenly interpreted the questions in the OP as questions.

hyksos wrote:Did you have anything to say about QBism?

"...some QBists have advocated a research program of reconstructing quantum theory from basic physical principles..."
The statements I gave model quantum reality from first principles. Given that, I'm not convinced that establishing their "QBist character" adds anything important (other than the QBist's own sense of self importance).

Any model that concedes a very early universe devoid of life and which also demands "participatory realism" is going to need God as the participant. That's fine with me.

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Re: Subjective Interpretation

The statements I gave model quantum reality from first principles. Given that, I'm not convinced that establishing their "QBist character" adds anything important (other than the QBist's own sense of self importance).

I had the same feeling in recent days. It's possible that QBism isn't even an Interp-of-QM per se. Maybe it is some re-interpretation of the Born Rule.

hyksos
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