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Thermodynamical cost of some interpretations of quantum theory

arxiv.org

11–20 of 21 posts

Re: Thermodynamical cost of some interpretations of quantum theory

#11

I haven't read the paper, nor am I an expert, but the assumption (i) sounds fishy "the decision of which measurement is performed on a quantum system can be made independently of the system". By fishy, I mean obviously false. Which means being incompatible with this assumption is OK. I'm probably missing something...

"Independently" is also a loaded word - one could mean that there's no direct causal connection between the state of the system and the state of the measurement apparatus, or one could mean that those two states are (in ensemble experiments) independent in the statistical sense. In order for Bell's theorem (and a lot of subsequent quantum theory) to work, we have to interpret causal and statistical independence as be…

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Re: Thermodynamical cost of some interpretations of quantum theory

#12
post #7

Earlier quoted context omitted.

The influence may be negligible, but it's theoretically there. The decision-maker is part of the same system (decision is happening within a system of neurons augmented with electronic tools, all of which exist in the same physical reality).

There are no neurons involved, essentially random number generators are making the decisions and in such experiments usually in the nanosecond range while particles are in flight between source and detector to ensure that the decision can not influence the creation and preparation process. And by using a source of randomness billions of light years away it becomes very unlikely that the particle source and the source…

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Re: Thermodynamical cost of some interpretations of quantum theory

#13
post #2

To save others some time. Input 1: authors check out (PRL, Nature pubs). Not a one-off crazy posting to arXiv. Input 2: Unless this your field, I'd be surprised if you get much from the paper other than interpretation of quantum mechanics is still an active field and information theory / thermodynamics has an important role in that field. Input 3: After a few reads, I don't like the phrasing the authors put on Type-I…

I agree on the phrasing issue. Both there "types" seem to require Bohr's classical observer, but as soon as you assume that observers are classical you've swept the big question under the carpet, which is, "Why is there a classical world at all?" Decoherence and similar approaches at least try to address this question, and don't fit at all well with their two-Type scheme.

Or to put it another way: observers are intrinsic to reality as well as the systems under observation, and any attempt to treat them separately will fail. But this is uninteresting, because any interpretation is going to have to acknowledge this at some level (as Bohr correctly pointed out quite a long time ago.)

Re: Thermodynamical cost of some interpretations of quantum theory

#14
post #7

Earlier quoted context omitted.

The influence may be negligible, but it's theoretically there. The decision-maker is part of the same system (decision is happening within a system of neurons augmented with electronic tools, all of which exist in the same physical reality).

There are no neurons involved, essentially random number generators are making the decisions and in such experiments usually in the nanosecond range while particles are in flight between source and detector to ensure that the decision can not influence the creation and preparation process. And by using a source of randomness billions of light years away it becomes very unlikely that the particle source and the source…

Isn't that just determinism followed to its logical end?

Re: Thermodynamical cost of some interpretations of quantum theory

#16

Science aside, I found the authorship fascinating and encouraging; it is composed of individuals from five different countries and cultures (Sweden, Germany, UK, Spain, and China). Is this typical for science?

Not that uncommon in quantum foundations, where researchers are often few and far between (partly due to the competitive academic job market).

Re: Thermodynamical cost of some interpretations of quantum theory

#17

Science aside, I found the authorship fascinating and encouraging; it is composed of individuals from five different countries and cultures (Sweden, Germany, UK, Spain, and China). Is this typical for science?

... and yet they are entangled ;-)

Re: Thermodynamical cost of some interpretations of quantum theory

#18
post #2

To save others some time. Input 1: authors check out (PRL, Nature pubs). Not a one-off crazy posting to arXiv. Input 2: Unless this your field, I'd be surprised if you get much from the paper other than interpretation of quantum mechanics is still an active field and information theory / thermodynamics has an important role in that field. Input 3: After a few reads, I don't like the phrasing the authors put on Type-I…

I agree on the phrasing issue. Both there "types" seem to require Bohr's classical observer, but as soon as you assume that observers are classical you've swept the big question under the carpet, which is, "Why is there a classical world at all?" Decoherence and similar approaches at least try to address this question, and don't fit at all well with their two-Type scheme. Or to put it another way: observers are intri…

If you've got Many Worlds at the back of your mind there, rest assured (!) that the lead author considers it to be a Type-I interpretation See http://arxiv.org/pdf/1509.04711v1.pdf

Re: Thermodynamical cost of some interpretations of quantum theory

#19
post #3
post #2

To save others some time. Input 1: authors check out (PRL, Nature pubs). Not a one-off crazy posting to arXiv. Input 2: Unless this your field, I'd be surprised if you get much from the paper other than interpretation of quantum mechanics is still an active field and information theory / thermodynamics has an important role in that field. Input 3: After a few reads, I don't like the phrasing the authors put on Type-I…

> Another way to say it may be that it's impossible to separate observation from the intrinsic properties of the world. I think it is more parsimonious to say that there are no intrinsic properties of the world that are not relational, not that they are impossible to separate from observation. It defeats the purpose of interpretations like relational quantum mechanics to hold on to the concept of an intrinsic reality…

"no intrinsic properties of the world that are not relational." I like that better. Thanks!

Re: Thermodynamical cost of some interpretations of quantum theory

#20

I haven't read the paper, nor am I an expert, but the assumption (i) sounds fishy "the decision of which measurement is performed on a quantum system can be made independently of the system". By fishy, I mean obviously false. Which means being incompatible with this assumption is OK. I'm probably missing something...

"Independently" is also a loaded word - one could mean that there's no direct causal connection between the state of the system and the state of the measurement apparatus, or one could mean that those two states are (in ensemble experiments) independent in the statistical sense. In order for Bell's theorem (and a lot of subsequent quantum theory) to work, we have to interpret causal and statistical independence as be…

"Bell, in particular, justified it by claiming that it was unscientific to assume that experimenters didn't have free will. Okay, sure." You make some good points. I am not sure how Bell meant this, but read out of context, this is obviously false. Deterministic modelling (and therefore lack of absolute free will of the components of the system) is a long tradition of science.
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