Time Flows Forward or Backward At Quantum Levels, Researchers Suggest (surrey.ac.uk) 67
"What if time is not as fixed as we thought?" That's the question raised in an announcement from the University of Surrey.
"Imagine that instead of flowing in one direction — from past to future — time could flow forward or backward due to processes taking place at the quantum level." This is the thought-provoking discovery made by researchers at the University of Surrey, as a new study reveals that opposing arrows of time can theoretically emerge from certain quantum systems. For centuries, scientists have puzzled over the arrow of time — the idea that time flows irreversibly from past to future. While this seems obvious in our experienced reality, the underlying laws of physics do not inherently favour a single direction. Whether time moves forward or backwards, the equations remain the same....
This discovery provided a mathematical foundation for the idea that time-reversal symmetry still holds in open quantum systems — suggesting that time's arrow may not be as fixed as we experience it... The research offers a fresh perspective on one of the biggest mysteries in physics. Understanding the true nature of time could have profound implications for quantum mechanics, cosmology and beyond.
The university's announcement includes this quote from co-author Thomas Guff, a research fellow in quantum thermodynamics.
"The surprising part of this project was that even after making the standard simplifying assumption to our equations describing open quantum systems, the equations still behaved the same way whether the system was moving forwards or backwards in time. When we carefully worked through the maths, we found this behaviour had to be the case because a key part of the equation, the 'memory kernel,' is symmetrical in time."
And their research reminds readers that "the fundamental laws of physics in both the classical and the quantum realms do not manifest any intrinsic arrow of time. Newton's equations are time-reversal symmetric, as well as Schrödinger's equation. As a consequence, backward-in-time motion is equally possible as forward-in-time motion... Our findings are consistent with the second law of thermodynamics and emphasise the distinction between the concepts of irreversibility and time-reversal symmetry."
"Imagine that instead of flowing in one direction — from past to future — time could flow forward or backward due to processes taking place at the quantum level." This is the thought-provoking discovery made by researchers at the University of Surrey, as a new study reveals that opposing arrows of time can theoretically emerge from certain quantum systems. For centuries, scientists have puzzled over the arrow of time — the idea that time flows irreversibly from past to future. While this seems obvious in our experienced reality, the underlying laws of physics do not inherently favour a single direction. Whether time moves forward or backwards, the equations remain the same....
This discovery provided a mathematical foundation for the idea that time-reversal symmetry still holds in open quantum systems — suggesting that time's arrow may not be as fixed as we experience it... The research offers a fresh perspective on one of the biggest mysteries in physics. Understanding the true nature of time could have profound implications for quantum mechanics, cosmology and beyond.
The university's announcement includes this quote from co-author Thomas Guff, a research fellow in quantum thermodynamics.
"The surprising part of this project was that even after making the standard simplifying assumption to our equations describing open quantum systems, the equations still behaved the same way whether the system was moving forwards or backwards in time. When we carefully worked through the maths, we found this behaviour had to be the case because a key part of the equation, the 'memory kernel,' is symmetrical in time."
And their research reminds readers that "the fundamental laws of physics in both the classical and the quantum realms do not manifest any intrinsic arrow of time. Newton's equations are time-reversal symmetric, as well as Schrödinger's equation. As a consequence, backward-in-time motion is equally possible as forward-in-time motion... Our findings are consistent with the second law of thermodynamics and emphasise the distinction between the concepts of irreversibility and time-reversal symmetry."
interesting (Score:2)
For it to be a testable hypothesis, we'd need a way to observe or measure time, or predict the effects of time. Not an exactly easy to do.
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They're claiming we can have effects before causes. Uh, no.
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I don't see why you wouldn't be allowed effects before causes, even in classical physics, provided that is from an external frame of reference. So long as the particle experiences cause and then effect, there shouldn't be any problem.
Re: interesting (Score:2)
Re: interesting (Score:2)
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Re: interesting (Score:3)
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What?! I liked those episodes. There were definitely worse ones to watch. The binary one for starters.
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I liked Q, both the classic Desmond Llewelyn iteration and Ben Whishaw's more modern geeky take. But yeah, he wouldn't have fit well into Star Trek. "Oh do pay attention Captain Kirk, now, this looks like an ordinary pen, but it contains compressed air, you can breath underwater for..." "Q, my communicator can create a breathable underwater submarine just by pressing this button, why would I need that thing?"
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The journalists that write up these articles always try to explain very specific scientific observations in a simple non-scientific way. And the end result is always ridiculous. Sometimes the journalists don't even understand the science, and other times their explanations are similar in form but not substance to the phenomena they are talking about. But it always has the feel of "wow, the world doesn't work the way we all experience it!" to get clicks.
The world of ordinary human experience sits on top o
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Can supermarket prices go up before a supply chain shock evrn hits?
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The answer is no of course not but that rely on us observing time going forward. The thing is how would you even tell, time went backwards. We are just machines that rely on time to operate so if a photon cause a neuron to fire it would un-fire if time goes backwards.
I was just recently pondering the same thing, why can't time go backwards? It would explain a few things like how quantum computers can do NP complete problems in polynomial time, its really not that stunning if you move time backwards and forw
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What about if prices go up for any number of reasons besides supply and demand (as mainstream EconLOL would have us believe) and cause-before-effect might well be one of those, either literally or figuratively implemented via derivative contracts which can bring future prices forward so you can trade them?
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What if time exists because it is a necessary component of the simulation? They just need a way to stop everything from happening all at once, so it appears to us as if there is cause and effect but all the events in the universe have already been programmed.
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From 2012 ... great minds think alike (although not identically) -- some just think of it sooner: It's all about time [aardvark.co.nz]
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Show me where they claim that. (Hint: you can't, because they don't.)
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Quantum clocks should have an accuracy sufficient to measure anything you could observe in an experiment.
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But you are observing in time, a clock can't measure time going backwards because they measure time. I classic example would be the double split experiment how does it know that the particle is being measured?
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This might be one of those theories that explains observed behaviour, but which isn't the only possible explanation. A model that can be used to make predictions, rather than a testable law.
The math maths! (Score:3)
the equations still behaved the same way whether the system was moving forwards or backwards in time
If you got a defined as valid result either way, that proves it! I'm convinced.
Re: The math maths! (Score:2)
curious definition of "fundamental law" (Score:2)
"the fundamental laws of physics in both the classical and the quantum realms do not manifest any intrinsic arrow of time..."
And yet to date there has never been any documented ability to travel in time except in one "intrinsic arrow of time". Good thing us "readers" are "reminded" by "their research" that this is not true.
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At classical scales of matter over classical scales of time, you are correct. However, that's also utterly irrelevant at the quantum scale.
Re:curious definition of "fundamental law" (Score:5, Interesting)
"the fundamental laws of physics in both the classical and the quantum realms do not manifest any intrinsic arrow of time..."
And yet to date there has never been any documented ability to travel in time except in one "intrinsic arrow of time". Good thing us "readers" are "reminded" by "their research" that this is not true.
The fact that many laws of physics work in either time-direction does not imply travel to the past is possible. It just means you can observe a system in its current state and infer what it looked like in the past.
There is one law of physics that is not time-symmetric: the second law of thermodynamics. Closed systems do not reduce their disorder spontaneously.(*) You don't see a broken glass on the kitchen floor suddenly jump back up to the counter and re-assemble itself.
(*) Well, it's possible by a sheer fluke that a system could re-order itself, but the probability of that happening is spectacularly small, so small that you would need to wait for the age of the universe multiplied by a ludicrously large number for it to happen.
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How come rocks under high temperature and pressure separate into bands of homogeneous minerals?
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How come rocks under high temperature and pressure separate into bands of homogeneous minerals?
I'm not a geologist, but I'll guess that it's differential buoyancy, seen in many systems with gases, liquids, or fluids present, along with a directed acceleration, usually caused by a gravitational field.
You can still see order appear in a closed system, but it's at the cost of using energy or generating disorder elsewhere in the system. The laws of thermodynamics still hold.
And now I'm not so sure I was correct that time-symmetric laws only mean you can infer what a system looked like in the past. There'
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"I'll guess that it's differential buoyancy"
Why do the bands interleave (unlike layered drinks)?
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"I'll guess that it's differential buoyancy"
Why do the bands interleave (unlike layered drinks)?
Again, I'm not a geologist, but I'll guess that what you're describing is called stratification, when layers shift at different speeds and collide due to differential motion of the earth's crust.
Ad that's as far as I can take this conversation. If you have any other questions, ask an actual geologist.
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What if when I ask geologists they handwave a lot and say things like "it comes out of the melt" without explaining how gravity, temperature, and pressure alone can produce layers of minerals that, self-similarly, alternate at the millimeter and up to the kilometer scale?
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I say again: ask a geologist. I'm not one.
It occurs to me now that your initial question may have had a loaded premise. Were you talking about sedimentary rock? As far as I know, that is not formed from "high temperature and pressure" but rather from successive layers of sediment that collect and harden over time into rock, thus producing the layered structures.
Your sequence of questions makes me suspect you have some kind of agenda, like a young-earth creationist.
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What if I became fascinated with bands in rock in the Swakane Terrane in eastern Washington, and the geologic explanations I found in papers in the library didn't seem like they had a clue as to how those bands could have formed, so a violation of thermodynamics on a macroscopic scale can't be ruled out except by mood affiliation?
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Can you reproduce it in a lab?
Time Reversal Violation Known since 1998 (Score:5, Interesting)
The fact that many laws of physics work in either time-direction
One of the two most fundamental laws of physics, the Standard Model, does not work the sime in either time-direction. The actual paper itself is factually wrong when it states that "the fundamental laws of physics in both the classical and the quantum realms do not manifest any intrinsic arrow of time.". They do in the quantum realm! While the paper is correct that newtonian mechanics and the Schrodinger equation symmetric under time reversal symmetry, the weak interaction in particle physics.is not and that definitely is in the quantum realm albeit the (special) relativistic quantum realm.
This asymmetry is associated with CP violation - the matter/antimatter asymmetry that somehow caused the universe to be full of matter instead of equal amounts of matter and anti-matter. While the exact mechanism for this is not yet understood we have observed CP-violation in the lab back as far as 1963 when its discovery won a Nobel prize. This meant that T-violation (time reversal) either also had to exist or it would mean that relativity was wrong because the combination of CP and T together (CPT) is a symmetry of relativity so so CP is broken then T also has to be broken so the combination of the two is preserved: it T were a perfect symmetry and CP were not then CPT would have ot be broken too.
T violation was first found in 1998 by the CPLEAR experiment [sciencedirect.com] looking at kaons and in 2012 the b-factory experiment, Babar, significantly improved on this result [aps.org]. Hence, at the most fundamental levels, we know for a fact that the laws of physics are not invariant under time reversal. This has nothing to do with thermodynamics: it is a fundamental property of the weak interaction.
More specifically time-reversal violation means that time cannot flow forward and backward equally at "quantum levels" because, if it did, it would be impossible to observe T-violation since any asymmetry would wash-out.
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If all evidence of the change is removed, are you left with an account of time that is just narrative?
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If all evidence of the change is removed
You'll need to explain how this could happen before we can discuss further. My position is that it can't. Any attempt to "remove" the evidence would itself leave evidence.
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Even if a system could re-order itself, that would not be time travel, time still moves forward.
Yes, exactly. My point was that we don't see such re-ordering, so we have no reason to wonder whether time can go backwards.
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Reversing time does not reverse the Universe (kinetics and other physical 'laws'). People who think they can travel back to previous instances are insane. The closest you can get is to travel faster than the speed of light and witness the light (information) from that period... and it seems pretty solid that we can not travel faster than light... so WTF people?
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How do you know?
Movie time travel has someone from the future "travelling" to the past with the subjective impression of their personal time continuing in the same direction. That's pretty unlikely. There's no reason that should happen, and lots of reasons it shouldn't. Much more plausible is that if you "travelled" "back" in time the reactions in your brain would go in reverse and you wouldn't notice anything unusual at all. Nor would anyone around you.
"Time runs in both directions" really should be interp
And it will be even more impressive (Score:5, Funny)
Ant Man and Endgame (Score:2)
Hmmm. (Score:3)
We could test whether the argument presented makes sense, but only if the quantum uncertainty principle is actually what I was taught (teachers aren't necessarily reliable).
What I was taught was that uncertainty in position times uncertainty in velocity cannot ever fall below Planck's constant.
If quantum particles can move freely in spacetime, then uncertainty in position is uncertainty in position in spacetime, not merely uncertainty in space. Which means the limits on precision in space alone can't ever be as tight as that. It also means, though, that you should be able to predict how this would impact interference pattern experiments, and then see if the prediction matches observation.
Penrose again? (Score:1)
Roger Penrose was stating that retro causality might explain the measurement problem in quantum mechanics in the last few years to explain how it might work⦠not exactly time travel but that causality is suspended for a period until it stabilises⦠and then collapses. Would look like time travel or entanglement etc from an external observerâ¦
Time travel is not provable (Score:2)
There's no way to prove time travel is possible. Every way you can think of to prove it is subject to elaborate bamboozlement. If you personally can travel back in time, then it's possible to be certain to 99.999% probability that you actually did travel back in time. But for someone to prove they themselves traveled back in time is hard. They'll have to say something like there's a dinosaur buried 100 meters underground or something like that. But then how can you be sure they didn't plant it?
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They'll have to say something like there's a dinosaur buried 100 meters underground or something like that. But then how can you be sure they didn't plant it?
Seems like there is a trivial solution: the "time traveler" asks the subject to define a widget and where he wants said widget to be planted, then goes back in time to do so, then allows the subject to dig up the widget themselves? This, of course, only proves anything to the subject--anyone else listening has no way of knowing if the time traveler and the subject are confederates.
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Hmm .. ok .,. but that's assuming the time traveler cannot freeze or slow time down radically for others and then have the widget buried somewhere. If the widget is a seed he can use growth stimulants to create a full grown plant/tree.
I admit it's contrived and would fail Occam's razor, kind of like "the universe is five seconds old" or the "you're only alive for 1 second" theory.
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There is no need to alter time for anyone else. Either the time traveler can travel, right then, into the past, do the thing, and come back to the exact point in time to continue his conversation, or if that isn't feasible ("I have to go get some plutonium for my DeLorean first") you can go the Bill & Ted route and dig it up first, then go back in time at some future point to have put the thing there in the first place.
What has two thumbs and doesn't care about causality? This guy!
Coordinate time flows in one direction (Score:1)
That's a tautology, not a fundamental insight.
How one reasons about time flowing backwards, while living in a macroscopic world with a constant ticking clock, is a matter of philosophy rather than physics in my mind.
Perhaps I can't escape my little pointland of a hyperspace of a reality and it's only a failure of my imagination.
But perhaps that limitation is still a limitation.
Ya, but ... (Score:2)
Time Flows Forward or Backward At Quantum Levels, Researchers Suggest
Pretty sure it's been determined that "time keeps on slippin', slippin', slippin' Into the future" [citation] [genius.com] by Steve Miller and his band [wikipedia.org] of associates.
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lol (Score:4, Interesting)
good (Score:3, Funny)
Can they go back to 1997 and tell me not to get married.
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Can they go back to 1997 and tell me not to get married.
Worse.
They can go back to 1965 and tell your parents not to have kids.
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Wait if I am the kid how is that worse?
Does the Tenet sequel come first? (Score:2)
Surrey (Score:2)
I can believe that backwards bit.
However (Score:2)
They are still trying to figure out if the next leap will be the leap home.
Perhaps we're like Ptolemy (Score:3)
We mis-perceive time because of our relative position in it, the way Ptolemy mis-perceived the motion of the sun and planets to come up with his Geocentric model of the universe.
We keep saying that time "flows", and it has a direction. We say that because we perceive that from our point of view. What if time isn't flowing but everything else is.
To analogize: What if we believe the world is really whizzing by, but the car we're in is stationary, as that's what it looks like from our point of view. Perhaps we and all matter are really what's in motion and "flowing", and the thing we're calling time is the static part?
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What if we believe the world is really whizzing by, but the car we're in is stationary, as that's what it looks like from our point of view. Perhaps we and all matter are really what's in motion and "flowing", and the thing we're calling time is the static part?
Perhaps I do not have a good grip on Relativity, but don't the equations say that it doesn't matter? Perhaps there is motion in both our point of view and the Universe at the same time?
Time doesn't do anything (Score:2, Interesting)
Time is simply our perception of change in the universe. Things change, and there is no process which would cause things to change in reverse. Time doesn't flow in any direction, and time travel is not possible. It is fun for science fiction, but isn't really rational.
On the right track (Score:1)
If you can't observe it, it's math, not science. (Score:2)
Funny, I just this week finished watching a very lengthy video essay by random youtuber "Chris 'The Brain'" who actually did a really decent job of convincing me that modern physicists are so open-minded they've let their brains fall out on the floor. "Time flows backwards" for the love 'o Mike!
Balderdash. Your math may allow this without breaking your priors, but reality doesn't. The reality is that information is carried by electrons. Electrons move in orbits. Changes in orbits generate waves. Waves prop
A 'solution' for the particle entanglement? (Score:2)