Experiment shows that arrow of time is a relative concept, not an absolute one

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Winston

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Experiment shows that arrow of time is a relative concept, not an absolute one

https://phys.org/news/2017-12-arrow-relative-concept-absolute.html

(Phys.org)—An international team of researchers has conducted an experiment that shows that the arrow of time is a relative concept, not an absolute one. In a paper uploaded to the arXiv server, the team describe their experiment and its outcome, and also explain why their findings do not violate the second law of thermodynamics.

The second law of thermodynamics says that entropy, or disorder, tends to increase over time, which is why everything in the world around us appears to unfold forward in time. But it also explains why hot tea grows cold rather than hot. In this new effort, the researchers found an exception to this rule that works in a way that doesn't violate the rules of physics as they have been defined.

The idea of entangled particles has been in the news a lot lately as researchers around the world attempt to use it for various purposes—but there is another lesser-known property of particles that is similar in nature, but slightly different. It is when particles become correlated, which means they become linked in ways that do not happen in the larger world. Like entanglement, correlated particles share information, though it is not as strong of a bond. In this new experiment, the researchers used this property to change the direction of the arrow of time.

The experiment consisted of changing the temperature of the nuclei in two of the atoms that exist in a molecule of trichloromethane—hydrogen and carbon—such that it was higher for the hydrogen nucleus than for the carbon nucleus, and then watching which way the heat flowed. The group found that when the nuclei of the two atoms were uncorrelated, heat flowed as expected, from the hotter hydrogen nucleus to the colder carbon nucleus. But when the two were correlated, the opposite occurred—heat flowed backward relative to what is normally observed. The hot nucleus grew hotter while the cold nucleus grew colder. This observation did not violate the second law of thermodynamics, the group explains, because the second law assumes there are no correlations between particles.
 
I seriously don't understand this paper. I love to read and think about the relationship between entropy and the arrow of time, but I can't tell if this paper is junk or not. I usually think of temperature was a bulk property that arrises from the energetic collisions between multiple particles. How can an individual atom have a temperature?

Regardless..."trichloromethane!" Physicists are funny. (lousy chemistry joke)
 
[video]https://www.bing.com/videos/search?q=monty+python+my+brain+hurts&view=detail&mid=AB84F95277626CCAFE4AAB84F95277626CCAFE4A&FORM=VIRE[/video]
 
A few days from now I'm going to edit the next line in this message, to make it appear a few minutes from now. New line inserted backwards in time by entangled particles follows:

----->>>>>> IT WORKED!!!!
 
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A few days from now I'm going to edit the next line in this message, to make it appear a few minutes from now. New line inserted backwards in time by entangled particles follows:

----->>>>>> IT WORKED!!!!

That was/will be fantastic!!!!


Sent from my iPhone using Rocketry Forum
 
Is the speed of light a constant? Absolutely (at least from my perspective).

s6
 
I can't tell if this paper is junk or not. I usually think of temperature was a bulk property that arrises from the energetic collisions between multiple particles. How can an individual atom have a temperature?

This case is even more confusing, the temperature of nuclei, but it appears that even subatomic particles can have a temperature.

Do subatomic particles have a temperature?

https://www.quora.com/Do-subatomic-particles-have-a-temperature

On the experiment in my original post:

Scientists Reverse Arrow of Time in Quantum Experiment

https://www.pbs.org/wgbh/nova/next/physics/scientists-reverse-arrow-of-time-in-quantum-experiment/

"Theoretical physicists had already predicted this could happen, but now we have proof that it’s possible."

Quantum physics is wonderfully weird. More time related weirdness:

Delayed choice quantum eraser (DCQE)

https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

Great video explaining the DCQE experiment starting at the 35 minute point:

[video=youtube;VqULEE7eY8M]https://www.youtube.com/watch?v=VqULEE7eY8M&t=35m0s[/video]

Physicists provide support for retrocausal quantum theory, in which the future influences the past

https://phys.org/news/2017-07-physicists-retrocausal-quantum-theory-future.html
 
I'm looking for a way to burn rocket fuel without it getting hot. Will this help me?
 
This case is even more confusing, the temperature of nuclei, but it appears that even subatomic particles can have a temperature.

Do subatomic particles have a temperature?

https://www.quora.com/Do-subatomic-particles-have-a-temperature

On the experiment in my original post:

Scientists Reverse Arrow of Time in Quantum Experiment

https://www.pbs.org/wgbh/nova/next/physics/scientists-reverse-arrow-of-time-in-quantum-experiment/

"Theoretical physicists had already predicted this could happen, but now we have proof that it’s possible."

Quantum physics is wonderfully weird. More time related weirdness:

Delayed choice quantum eraser (DCQE)

https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

Great video explaining the DCQE experiment starting at the 35 minute point:

[video=youtube;VqULEE7eY8M]https://www.youtube.com/watch?v=VqULEE7eY8M&t=35m0s[/video]

Physicists provide support for retrocausal quantum theory, in which the future influences the past

https://phys.org/news/2017-07-physicists-retrocausal-quantum-theory-future.html

So when the authors say "temperature" they mean something entirely different than what we generally think of temperature on a macro scale. I'll buy that.

And the video that you posted is great, though it gets preachy about informational theory at the end. That's one of the best examples of quantum entanglement that I've ever seen.

FWIW...I was reading a department of defense request for proposals earlier this week. They are looking for ways to detect objects at a distance via quantum entanglement. We are likely to see real applications of this stuff in the next couple decades.
 
Keep in mind only random information is transmitted by entanglement. Otherwise, it is a violation of causality and, hence, a violation of relativity.
 
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FWIW...I was reading a department of defense request for proposals earlier this week. They are looking for ways to detect objects at a distance via quantum entanglement. We are likely to see real applications of this stuff in the next couple decades.
And the Chinese are exploring military uses, too. Google search link:

https://www.google.com/search?q=chinese+military+use+quantum&oq=chinese+military+use+quantum

Plus, it is claimed that cryptocurrency blockchains will be threatened by quantum computers as will every form of encryption now known.
 
Some of these weird concepts are theoretically possible but with our current technology impractical. That doesn't mean that it will never be tamed.

There is a proposed propulsion method that relies on negative mass. Negative mass can be made in small quantities currently, but the energy required is enormous and containment is difficult. Add in the fact that it really messes with your mind (for example it has negative inertia!) it is currently in the impractical phase still.
https://en.wikipedia.org/wiki/Negative_mass

Now ponder on such things as negative refraction and inverse Doppler effect :eek:
 
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