Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Oil droplets guided by pilot waves do not give rise to double-slit interference

quantamagazine.org

Post reply on HN
Print view View original

11–20 of 130 posts

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#11

Post by everdev »

pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

It's more like seeing one boy actually impacts the gender of the second child, which is why the quantum experiment is so mind boggling. It doesn't seem to have any resemblance with classical physics and only makes sense in quantum physics.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#12

Post by pg_bot »

everdev wrote: post #11
pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

It's more like seeing one boy actually impacts the gender of the second child, which is why the quantum experiment is so mind boggling. It doesn't seem to have any resemblance with classical physics and only makes sense in quantum physics.

That's exactly what the paradox states. Seeing one boy does affect the gender of the second child.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#13

Post by dumbfoundded »

pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

I think the problem with QM isn't the fact that the probabilities are confusingly calculated. It's that there's no underlying mechanism.

Imagine I flip a fair coin. The odds of you guessing it correctly are 50%. In your mind, you know it's probabilistic. Simultaneously, you imagine that if you had more information you could get it right more than 50% of the time. Maybe if you new the force or the initial velocity, that'd help. The thing with QM, there's no more information to get. You can't get better than 50%, ever. It's basically magic. The problem with any deterministic model is that it adds more complexity than just assuming magic and we can't test any of the predictions of current deterministic models so why bother.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#14

Post by reitzensteinm »

pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

I think the way you stated the first problem is ambiguous; the answer could be 1/2 or 2/3. After all, maybe you only have that information because you've met just one of your neighbour's children who happens to be a boy.

The Wikipedia article does a great job of being explicit in the differences between the 1:2 and 2:3 cases.

Unfortunately articles pop up every now and then claiming 2:3 is the correct answer (since it's counterintuitive and therefore interesting), while losing the conditions necessary for 2:3 in the translation of the problem description from mathematical to plain English.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#15

Post by pmikesell »

pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

No, that is not what this says. What this says is that there is ambiguity in the description of the situation. Is the question about the probability of a second girl in the set of all families with 2 children and at least one boy, or is the question about the probability of a second girl in the set of all families with 2 children given that we know one of them is a boy.

They are different sets of families. That is the point of this paradox.

This has nothing to do with quantum mechanics.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#16

Post by dumbfoundded »

pg_bot wrote: post #12
everdev wrote: post #11

Earlier quoted context omitted.

It's more like seeing one boy actually impacts the gender of the second child, which is why the quantum experiment is so mind boggling. It doesn't seem to have any resemblance with classical physics and only makes sense in quantum physics.

That's exactly what the paradox states. Seeing one boy does affect the gender of the second child.

It's not a paradox if you put it in less confusing language.

There are 4 possibilities: GG GB BG BB

GG is impossible so you have GB, BG, & BB. One of them is a B, what's the other. Well that's clearly 2 / 3 G.

The other one situation is completely. It's basically just the chance of a child being a girl.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#17

Post by pg_bot »

pmikesell wrote: post #15
pg_bot wrote: post #9

I was thinking about the double-slit problem the other day, and was trying to make connections to any other phenomenon that exists in the natural world and I think I came up with one. In conditional probability theory, there exists something called the boy or girl paradox. The paradox shows that the likelihood of an event can be drastically affected by how you know even seemingly innocuous information. I think that o…

No, that is not what this says. What this says is that there is ambiguity in the description of the situation. Is the question about the probability of a second girl in the set of all families with 2 children and at least one boy, or is the question about the probability of a second girl in the set of all families with 2 children given that we know one of them is a boy. They are different sets of families. That is th…

Say my wife tells me that the neighbor has 2 kids and one of them is a boy what is the likelihood that their other child is a girl?

Given what I know about the current situation, the probability that their other child is a girl is 66.666%

If I look out the window to that neighbor's yard and see a boy playing outside, the probability that their other child is a girl drops to 50%.

How I know the information about on data point one affected the likelihood of an unrelated one. What seems like identical knowledge on the outside, changes outcomes based on how I accrued that knowledge. If that doesn't mimic the double-slit experiment, I don't know what does.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#18

Post by perl4ever »

pg_bot wrote: post #17
pmikesell wrote: post #15

Earlier quoted context omitted.

No, that is not what this says. What this says is that there is ambiguity in the description of the situation. Is the question about the probability of a second girl in the set of all families with 2 children and at least one boy, or is the question about the probability of a second girl in the set of all families with 2 children given that we know one of them is a boy. They are different sets of families. That is th…

Say my wife tells me that the neighbor has 2 kids and one of them is a boy what is the likelihood that their other child is a girl? Given what I know about the current situation, the probability that their other child is a girl is 66.666% If I look out the window to that neighbor's yard and see a boy playing outside, the probability that their other child is a girl drops to 50%. How I know the information about on da…

It doesn't make sense to me that in order to get the probability of 2/3, you implicitly consider "a boy and a girl" to be different from "a girl and a boy".

Somehow, you're saying that seeing the boy means you have ruled out the possibility of "a girl and a boy". But the ordering is in no way related to some arbitrary observation. It's just lexical.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#19

Post by perl4ever »

dumbfoundded wrote: post #16
pg_bot wrote: post #12

Earlier quoted context omitted.

That's exactly what the paradox states. Seeing one boy does affect the gender of the second child.

It's not a paradox if you put it in less confusing language. There are 4 possibilities: GG GB BG BB GG is impossible so you have GB, BG, & BB. One of them is a B, what's the other. Well that's clearly 2 / 3 G. The other one situation is completely. It's basically just the chance of a child being a girl.

But are those ordered pairs or sets of two items each?

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#20

Post by kgwgk »

platz wrote: post #4
soveran wrote: post #3

All the paradoxes disappear if we use Quantum Field Theory instead of Quantum Mechanics. I would really like someone with deep knowledge on Quantum Theory to explain if something is wrong with a theory that otherwise makes a lot of sense to me. A good read on the topic is the paper "There are no particles, there are only fields" — https://arxiv.org/pdf/1204.4616.pdf

You can say that the only thing that exists is the quantum wave function, as what basically this paper says (particles are epiphenomena). That is basically hard-line Everettianism e.g. many worlds. There are still problems. QFT does not explain gravity very well either. The paper claims "it's neutral on the interpretations" - it is not. You have the most senior research professor of physics at caltech admitting there…

> You have the most senior research professor of physics at caltech

What is the ranking of seniority of research professors at Caltech? Are you implying that a research professor is somehow better than a “regular” professor?

Post reply on HN