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

[C C]

https://phys.org/news/2017-12-arrow-rela...olute.html

EXCERPT: 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....

Abstract: The second law permits the prediction of the direction of natural processes, thus defining a thermodynamic arrow of time. However, standard thermodynamics presupposes the absence of initial correlations between interacting systems. We here experimentally demonstrate the reversal of the arrow of time for two initially quantum correlated spins-1/2, prepared in local thermal states at different temperatures, employing a Nuclear Magnetic Resonance setup. We observe a spontaneous heat flow from the cold to the hot system. This process is enabled by a trade off between correlations and entropy that we quantify with information-theoretical quantities....

MORE: https://phys.org/news/2017-12-arrow-rela...olute.html

http://www.dailymail.co.uk/sciencetech/a...wards.html

[FluidSpaceMan]

I don't get what this has to do with the arrow of time. Are they saying that correlation of involves some sort of time reversal? A thermodynamic reaction appears to have run backward. I would like to be sure that there is nothing in the system that would act as a pump to cause this local decrease in entropy.

[Syne]

Depending on how much you equate information with entropy, it appears this could be interpreted as no violation of thermodynamic law (i.e. no reversal of the arrow of time).

"For initially correlated systems, we observe a spontaneous
heat current from the cold to the hot spin and show that
this process is made possible by a decrease of the mu-
tual information between the spins. The second law for
the isolated two-spin system is therefore verified"
- https://arxiv.org/pdf/1711.03323.pdf

[C C]

That's why I put quotation marks around its assertion, for any new members here. This is just part of the usual weekly output where yet another _X_ team maintains its job security. Most likely unmemorable. In the last decade alone there have been so many middling to "astounding" announcements made in theoretical physics -- that are forgotten a few months later and seldom if ever addressed again -- that an oil tanker could be filled with their neglected corpses (lack of pursuing).

Because of the differing interpretative preferences of scientists (theory-ladenness as well as any blatant loyalties to their favorites), you can take it for granted that a claim made by either a research team itself or as framed by the science journalists reporting on it will be alternatively re-conceived, challenged, or disputed. Few things are ever settled in this abstract playground other than the potential for a particular _X_ construct to garner a good record at predictions. Or in demonstrating practical usefulness in cutting-edge technology or aiding another human endeavor. But with rival interpretative views still dogging its heels, or it being variably realized in a scientific realism context (whenever this or that physicist takes a notion to jump so ontological / philosophical out of a 6-story high window).

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[RainbowUnicorn]

https://phys.org/news/2017-12-arrow-rela...olute.html

EXCERPT: 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....

Abstract: The second law permits the prediction of the direction of natural processes, thus defining a thermodynamic arrow of time. However, standard thermodynamics presupposes the absence of initial correlations between interacting systems. We here experimentally demonstrate the reversal of the arrow of time for two initially quantum correlated spins-1/2, prepared in local thermal states at different temperatures, employing a Nuclear Magnetic Resonance setup. We observe a spontaneous heat flow from the cold to the hot system. This process is enabled by a trade off between correlations and entropy that we quantify with information-theoretical quantities....

MORE: https://phys.org/news/2017-12-arrow-rela...olute.html

http://www.dailymail.co.uk/sciencetech/a...wards.html

what temperature is a black hole ?

[stryder]

https://phys.org/news/2017-12-arrow-rela...olute.html

EXCERPT: 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....

Abstract: The second law permits the prediction of the direction of natural processes, thus defining a thermodynamic arrow of time. However, standard thermodynamics presupposes the absence of initial correlations between interacting systems. We here experimentally demonstrate the reversal of the arrow of time for two initially quantum correlated spins-1/2, prepared in local thermal states at different temperatures, employing a Nuclear Magnetic Resonance setup. We observe a spontaneous heat flow from the cold to the hot system. This process is enabled by a trade off between correlations and entropy that we quantify with information-theoretical quantities....

MORE: https://phys.org/news/2017-12-arrow-rela...olute.html

http://www.dailymail.co.uk/sciencetech/a...wards.html

what temperature is a black hole ?

Well the theory is that every that is pulled into a blackhole is both spaghettified and effected by an event horizon, so while you have a set value of quanta going it, it potentially occupies a greater space than normal and is slowed. So entropically it would suggest that from the universes "flat" perspective, it would actually be cold, not just from sucking in energy but from the spacial distortion and the slowing of time. There is still the question as to whether a blackhole however is actually a destructive force, and isn't just a warping of spacetime. This would mean that from the relative perspective of something entering one, it wouldn't be distorted (time would appear to move normally) as to whether the rest of the universe would appear distorted that would be pure speculation.

Personally though I feel blackholes are still extremely speculative, I mean they are a theory to address anomalies that can't be understood without something filling the gap. While there is a lot of talk of blackholes online, I've yet to see Science literally point at one and prove they actually exist.

As for the actual experiment, it would be rather interesting if the same sort of experiment could be conducted in regards to Gravity and orbital body alignment, to see not just gravities attraction property but also repulsive property.

[elte]

I recall that they knew them only as quasars.

[Yazata]

Physicists are playing metaphysician again.

"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."

That's an awfully strong statement that seems to me to sneak in an answer to a metaphysical question about how best to understand and explain the arrow of time. It suggests that they have a stronger grip on the nature of time than they really do.

I'm certainly not a physicist, but I'm more inclined to attribute the arrow of time to the direction of causality. Events now have effects in the future, not in the past. And I don't think that the direction of causality is the same thing as the second "law" of thermodynamics.

I think that the reason physicists don't want to use causality to define the arrow of time is that their equations of mechanics are all time-reversal-invariant. The mathematical functions work equally well both ways. The only place time-asymmetry shows up in their mathematics seems to be in thermodynamics. So thermodynamics becomes the explanation for why time is asymmetric in their minds.

I'd be more inclined to say that the fact that their equations of mechanics don't successfully model the arrow of time is an indication of a defect in those equations. Far from being experimentally perfect as far as is known, there's a huge and obvious aspect of reality that they don't even successfully address.

[Syne]

The Second Law of Thermodynamics is actually about usable energy. Entropy is the loss of energy usable in performing work (causing things). This quantum system they describe, cannot perform work in any real, much less classical, macroscopic, sense. So they're just equivocating that the second law is violated.

[C C]

Physicists are playing metaphysician again. [...] Far from being experimentally perfect as far as is known, there's a huge and obvious aspect of reality that they don't even successfully address.

It's reminiscent of what Rosenberg refers to at bottom in regard to gray areas open to interpretation. Where a particular science eventually "decrees something" or settles on a particular candidate view just to fill what might otherwise be an empty placeholder or confusion of varying opinions in the student textbooks. And then admitted scientism folk like him run with it afterwards like it is a permanent fact or unchallenged gospel truth.

"By the authority of the Research / Theory Priests of _X_ Discipline this issue has been settled." The remaining objections / criticism dispensed to the dustbin. (Perhaps actually most often by the aforementioned textbook writers themselves and prolific science authors / journalists with dominant personalities. Rather than some supposed, legislative council of peers.)

A formal system has to decide what its own abstract residents are going to be, what belongs to or is coherent with it. And an enterprise like science is so heavily riddled with quantitative constructs that certain agents of it probably can't help but deem their profession as needing to do the same at times, with its loose ends. Especially with regard to satisfying students and the interested public / fan base.

An Interview With Alex Rosenberg
http://blog.talkingphilosophy.com/?p=4209

You are strongly committed to the view that “the methods of science are the only reliable way to secure knowledge of anything”? What would you say to those who would suggest that the methods of science can give us no knowledge about mathematics and what it is like to see red?

Alex Rosenberg: What I say in response to such sophisticated philosophical challenges is first, like all the other metaphysical and epistemological alternatives, scientism does not yet have a satisfactory account of mathematics or our understanding of it; second, the so-called “hard problem” of consciousness—what its like to have a qualitative experience—is a sign post along the research program of neuroscience. It will eventually have to dissolve this problem, just as physics eventually had to dissolve Zeno’s paradox of motion. Meanwhile, if I have to weigh the achievements of science in the balance against the problems of the philosophy of mathematics and the first person point of view, I’ll choose science. 400 years of ever-increasing depth and breadth in explanation and prediction carries a lot more weight with me than a handful of philosophical conundrums and Platonism about mathematics.

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