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Spooky action at a distance' could create a nearly perfect clock


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Physicists imagine a day when they will be able to design a clock that's so precise, it will be used to detect subtle disturbances in space-timeor to find the elusive dark matter that tugs on everything yet emits no light. The ticking of this clock will be almost perfect.

https://www.msn.com/en-gb/entertainment/news/spooky-action-at-a-distance-could-create-a-nearly-perfect-clock/ar-BB1d04gd?ocid=BingNews

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Entanglement conveys no information. The sources of this pop article seem not to know that. Saplakoglu writes:

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A decade ago, Vuletić and his team, along with researchers from the University of Belgrade in Serbia, had an idea for how to overcome this limitation: Entangle the particles.
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So, by entangling the atoms that keep time, the scientists might be able to keep each pair or group of entangled atoms in the same state and thus oscillating at similar frequencies


It just doesn't work like this. A pair of particles unmeasured are not meaningfully in any state at all. If measured, they're not entangled.

Some logical fails follow:

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Entangling the atoms makes the tosses less random, so to speak," Vuletić said. "The toss of each atom individually is still random, but all the tosses together have less randomness than those of independent atoms." It's similar to placing 100 coins on a table, 50 heads up and 50 tails up. If you pick up any coin without looking, it will be randomly heads or tails. But once you pick up all the coins, there will be exactly equal numbers of heads and tails. "Quantum entanglement is a little like that," he said.


No, it is not at all like placing 100 coins with 50/50 mix. That implies a measurement already taken. It's more like having 100 unknown coins and measuring 99 of them gives zero clue as to what the last one will be.  Entanglement is like slicing 100 coins in half and sending the 100 halves to Pluto.  Now if you count the halves here on Earth, you know what the Pluto guy will count if he ever looks at them. Nevertheless, the Pluto guy will have no idea what the last one will be if he hasn't received a message from Earth about the expected totals.
I'm saying that either this 'Vuletić and his team' are complete fools, or their suggestions are being completely misrepresented by this Saplakoglu pop-science article writer.
 

What I suspect is going on is having 50 coins split in half and all put on the table. Then, without measuring any of them, you know ahead of time that it's a 50/50 split. Nobody is carrying any of the coins elsewhere, and somehow having them entangled in pairs like that makes some kind of measurement more stable on average, thus allowing construction of a better clock.  I'm guessing. The author of the article doesn't seem to comprehend the concepts involved.

Edited by Halc
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The improvement comes from spin squeezing; one partner of the entanglement has much less uncertainty in a particular state than the other, and this gets them below the standard quantum limit.

They tout the improvement in the measurement but not the actual stability, which is more than an order of magnitude worse than the better optical frequency standards. That’s not to say that they won’t get there, though.

https://arxiv.org/pdf/2006.07501.pdf

3 hours ago, Halc said:

 

I'm saying that either this 'Vuletić and his team' are complete fools, or their suggestions are being completely misrepresented by this Saplakoglu pop-science article writer.

I’d put my money on the latter being closer to the truth

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16 hours ago, Halc said:

Entanglement conveys no information. The sources of this pop article seem not to know that. Saplakoglu writes:


It just doesn't work like this. A pair of particles unmeasured are not meaningfully in any state at all. If measured, they're not entangled.

Some logical fails follow:


No, it is not at all like placing 100 coins with 50/50 mix. That implies a measurement already taken. It's more like having 100 unknown coins and measuring 99 of them gives zero clue as to what the last one will be.  Entanglement is like slicing 100 coins in half and sending the 100 halves to Pluto.  Now if you count the halves here on Earth, you know what the Pluto guy will count if he ever looks at them. Nevertheless, the Pluto guy will have no idea what the last one will be if he hasn't received a message from Earth about the expected totals.
I'm saying that either this 'Vuletić and his team' are complete fools, or their suggestions are being completely misrepresented by this Saplakoglu pop-science article writer.
 

What I suspect is going on is having 50 coins split in half and all put on the table. Then, without measuring any of them, you know ahead of time that it's a 50/50 split. Nobody is carrying any of the coins elsewhere, and somehow having them entangled in pairs like that makes some kind of measurement more stable on average, thus allowing construction of a better clock.  I'm guessing. The author of the article doesn't seem to comprehend the concepts involved.

Once I have the picture of coins in my head I cannot rid myself of the coin midway  ( on it's edge) ( a third state )in my minds eye. I then have to rid myself of this by trying to imagine a coin of infinite thinness.  In a cashless universe what will physicists of the future use?  Is there anything better than coins to demonstrate such concepts., or am I stuck with one always on edge?  The author of the article doesn't seem to comprehend the concepts involved either, but he does enjoy trying ;)

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1 hour ago, alternativegmale@gmail.com said:

Once I have the picture of coins in my head I cannot rid myself of the coin midway  ( on it's edge) ( a third state )in my minds eye. I then have to rid myself of this by trying to imagine a coin of infinite thinness.  In a cashless universe what will physicists of the future use?  Is there anything better than coins to demonstrate such concepts., or am I stuck with one always on edge? 

The main problem is trying to explain quantum effects with classical analogies; such efforts always fall short, even when readers overstep and impart more meaning to the analogy than was intended. 

1 hour ago, alternativegmale@gmail.com said:

 The author of the article doesn't seem to comprehend the concepts involved either, but he does enjoy trying ;)

That may be, but one needs to understand QM to begin to make such an assessment 

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