It's Rewind Time - Scientists revert three qubits 'fractions of a second back in time'

[rcmaehl]

Source:
Phys.org (Best read)

Newseek (Simplified)
Whitepaper (Original)

 

Summary:

Scientists successfully returned three qubits to their original state . Results show naturally occurring reversal and reversal of atoms or electrons is exponentially unlikely

Media:

 

Quotes/Excerpts:

Quote

Scientists have demonstrated time reversal in a quantum computer, returning three qubits to their state a fraction of a second earlier. In a study published in the journal Scientific Reports, scientists from the U.S. and Russia have experimentally demonstrated time reversal—sending a qubit from a more complicated state to a simpler one. Lead author Gordey Lesovik said in a statement: "This is one in a series of papers on the possibility of violating the second law of thermodynamics. That law is closely related to the notion of the arrow of time that posits the one-way direction of time: from the past to the future." In the experiment, researchers set the state of each qubit to what you would think of as zero. From this point, the order is lost and the qubits became more and more complex, changing to a pattern of zeros and ones. Next, time was reversed by a specially developed program that allows the quantum computer to go from a state of chaos to order—going from complex to simple. As a result, the qubits are sent backwards in time. The program was successful in a two qubit quantum computer around 85 percent of the time. When a third qubit was introduced, more errors occurred and the success rate fell to around 50 percent. Furthermore, it indicates time reversal in nature is unlikely because it is too complex. “Such an unfortunate growth of the complexity explains why do we not observe such time-reversed objects in the Nature, The probability of a spontaneous appearance of a time-reversed object (particle of a system of particles) is negligible." Their time reversal could be used to test quantum computer programs. “In quantum computation, unlike the classical analog, we cannot interrupt the computation process until the very end. “Perhaps to the disappointment of science-fiction fans, I should point out that the article does not discuss time travel, or going back to the past, or reversing the principle of cause and effect”

 

My Thoughts:
Allons-y, it will definitely be interesting to see additional research into this. Is it only certain quantum information such as spin, or is it all of it? Is it actually making them simple from their complex state and is this something that will naturally occur in some sort of Big Crunch? Will this be another Faster Than Light Neutrino incident? Regardless, it's definitely interesting to see considering many scientific laws are time-agnostic.

[PlayStation 2]

Am I correct to say that the takeaway is that while actual time travel is plausible, it won't be obtainable on a practical scale, at least for a long time?

[rcmaehl]

5 minutes ago, handymanshandle said:

Am I correct to say that the takeaway is that while actual time travel is plausible, it won't be obtainable on a practical scale, at least for a long time?

It is likely to never be obtainable in a practical scale due to it's complexity. 

[PlayStation 2]

1 minute ago, rcmaehl said:

It is likely to never be obtainable in a practical scale due to it's complexity. 

Alright, that's what I was thinking; either not obtainable for a hellishly long time or not obtainable on a practical scale.

[Mira Yurizaki]

Is it time travel if they're returning the state of the system to a previous one?

[imreloadin]

Are the qubits actually "time-reversed" or are they simply just being "re-ordered"? My interpretation might be completely wrong but once a qubit changes its state can it never go back to that previous state without the reversal of time? It's like the picture in the OP with the billiards table, when you break them with the cue ball the system goes from an ordered state to a complex state. However, we can just re-rack the balls and place them back into the ordered state while still following the normal arrow of time. I'm not a physicist nor can I even pretend to do the types of complex maths involved with this but how do we know that they aren't just "re-racking" the qubits back to their original state while following the normal arrow of time?

[rcmaehl]

3 minutes ago, Mira Yurizaki said:

Is it time travel if they're returning the state of the system to a previous one?

Yes and no. Direct reversion of their state shouldn't be possible though and as such it is reverting something to an earlier state of time based on current scientific understandings. 

[Mira Yurizaki]

2 minutes ago, rcmaehl said:

Yes and no. Direct reversion of their state shouldn't be possible though and as such it is reverting something to an earlier state of time based on current scientific understandings. 

If it "shouldn't be possible", then I think that warrants further investigation.

[trevb0t]

10 minutes ago, Mira Yurizaki said:

Is it time travel if they're returning the state of the system to a previous one?

Fair question... Does this actually constitute "Travel."? I don't believe it does.

[rcmaehl]

9 minutes ago, imreloadin said:

Are the qubits actually "time-reversed" or are they simply just being "re-ordered"? My interpretation might be completely wrong but once a qubit changes its state can it never go back to that previous state without the reversal of time? It's like the picture in the OP with the billiards table, when you break them with the cue ball the system goes from an ordered state to a complex state. However, we can just re-rack the balls and place them back into the ordered state while still following the normal arrow of time. I'm not a physicist nor can I even pretend to do the types of complex maths involved with this but how do we know that they aren't just "re-racking" the qubits back to their original state while following the normal arrow of time?

The entropy of a closed system is decreasing which breaks our current understanding of Thermodynamics. With our current understanding saying they're "time traveling" is correct acceptable, but this will likely be revised once we better understand what's going on.

[imreloadin]

6 minutes ago, rcmaehl said:

The entropy of a closed system is decreasing which breaks our current understanding of Thermodynamics. With our current understanding saying they're "time traveling" is correct acceptable, but this will likely be revised once we better understand what's going on.

Doesn't the program they run on the qubits count as an input in this instance? Wouldn't that make it not a "closed system"?

[Ithanul]

5 minutes ago, Mira Yurizaki said:

Is it time travel if they're returning the state of the system to a previous one?

 

From the article:

Quote

“Perhaps to the disappointment of science-fiction fans, I should point out that the article does not discuss time travel, or going back to the past, or reversing the principle of cause and effect”

 

So no, they are not talking about time travel.  My best guess, time reversal was the current best term they decided on to describe what is going on within the close system.

[Mira Yurizaki]

2 minutes ago, Ithanul said:

So no, they are not talking about time travel.  My best guess, time reversal was the current best term they decided on to describe what is going on within the close system.

That's why I asked the question in the first place. It's kind of a dangerous to call it that even if that's the best they can come up with.

[Eastman51]

28 minutes ago, handymanshandle said:

Alright, that's what I was thinking; either not obtainable for a hellishly long time or not obtainable on a practical scale.

Just fly at high velocity around a very large black hole. The time warp caused by the extreme speed and gravity (lightspeed or faster, if possible) would allow you to travel into the future at an exponential rate.

[Ithanul]

2 minutes ago, Mira Yurizaki said:

That's why I asked the question in the first place. It's kind of a dangerous to call it that even if that's the best they can come up with.

Understandable.  I agree, probably not the best term to use.

 

Probably has to be taken in context with how the second law of thermodynamics works.

Simplify statement of that law:

Quote

Second law of thermodynamics—an isolated system either remains static or evolves toward a state of chaos rather than order.

 

[Curufinwe_wins]

1 hour ago, imreloadin said:

Are the qubits actually "time-reversed" or are they simply just being "re-ordered"? My interpretation might be completely wrong but once a qubit changes its state can it never go back to that previous state without the reversal of time? It's like the picture in the OP with the billiards table, when you break them with the cue ball the system goes from an ordered state to a complex state. However, we can just re-rack the balls and place them back into the ordered state while still following the normal arrow of time. I'm not a physicist nor can I even pretend to do the types of complex maths involved with this but how do we know that they aren't just "re-racking" the qubits back to their original state while following the normal arrow of time?

 

They are reordered in that sense yes. And no, it doesnt violate thermodynamics laws in any way shape or form. 

 

“Perhaps to the disappointment of science-fiction fans, I should point out that the article does not discuss time travel, or going back to the past, or reversing the principle of cause and effect”

 

 

hahaha sorry someone else already clarified. Idk who thought up the name for time-reversed in this sense, because there are other senses that discuss time reversal of matter and what that hypothetically might mean (like time-reversed matter looking like anti-matter and thus quite probably exhibiting the same explosive reactions with normal matter).

 

Obviously this sense is not compatible with the sense used in the paper. And they are talking explcitly about reversing local entropy of the system. Which is as a general paper, not very interesting to be perfectly honest. Maybe some other people with more direct quantum computing experience can point out the more novel and worthwhile aspects of this paper.

 

At least that is more or less true as long as CPT symmetry is the law of the land, which still looks correct based on every test we've done so far.

 

[NinJake]

Nothing like trying to travel back in time just to find out your atomic structure re-built yourself with 2 left hands and 1 missing testicle.

[Taf the Ghost]

1 hour ago, rcmaehl said:

Yes and no. Direct reversion of their state shouldn't be possible though and as such it is reverting something to an earlier state of time based on current scientific understandings. 

Their main problem is they currently don't understand them. Also, as a practical, scientific reality, your System always breaks down at the edges. As other counter forces start to become apparent, your model tends to die horribly as it approaches hard limits. It's going to take them years to sort things out like this.

 

That being said, when you get to the point of entangled Qubits, other effects could be in play. The quoted section points to the issues around Entropy and what that looks like at the utter edges of the physical world. There's also the issue we have a long ways to go to understand what entangled Qubits actually do to each other. It's probably another century of work or more. That's both the fun and unfun parts of new areas of science. All we know is that "everyone is wrong", so what you're working on is being slightly less wrong than yesterday.

 

Also, there may end up being weird relativistic effects that are taking place from entanglement. Rather than resetting the Qubits, it might actually be that there is a lag in them showing up in the relativistic time of the machine itself, as a result what they're really doing is stopping the process in mid-action and it returns to the previous state.

[yian88]

26 minutes ago, NinJake said:

Nothing like trying to travel back in time just to find out your atomic structure re-built yourself with 2 left hands and 1 missing testicle.

But now my dick is bigger so its worth a trade.

 

I dont think this is time travel at all, from what i understand they just reverted the state of the particles to what they were before they did not altered the time space they came from or were in at all. 

Its like having a self driving car that you can save its position in garage take it out and then automatically goes back in the same position when you dont need it anymore, but being done at atomic level.

Fuck do i know.

[CarlBar]

My read on this is that they've done somthing that violates the second law of thermodynamics and somthing about that has allways been the stumbling block vis a vis the practical realisation of time travel.

[Syntaxvgm]

It only takes a few hours to get a winning powerball ticket for these scientists. Godspeed. 

[Arika]

So Tracer from overwatch is actually possible 

[Sauron]

4 hours ago, rcmaehl said:

Results show naturally occurring reversal and reversal of atoms or electrons is exponentially unlikely

Ok, but... if I take a bottle of milk out of the fridge and put it back that doesn't mean I went back in time, regardless of how unlikely it is for the bottle to go back in the fridge on its own.

Quote

sending a qubit from a more complicated state to a simpler one

What matters here is that this violates thermodynamics, not that it's highly unlikely to occur in nature.

[BuckGup]

So if you consider time a dimension you can return to the exact position you were standing in 10 minutes later and if you were to simply look at that exact moment you didn't move positions but traveled 10 minutes into the future or since you know where you were 10 minutes ago in the past? You aren't the same person though as you are 10 minutes older so I wouldn't call it time traveling. It might make sense though how reverse time travel is not possible. It's simply a version of you 10 minutes ago but living in the now. I could see that as plausible for this. Essentially cloning something from the past into the present. Or freezing something in the present and unfreezing it later. The science behind that is well beyond me and probably most scientists on earth currently. It does this one thing, Why? Because it just does

[BlockedTheShot]

How long until i can go back in time to prevent lebron getting injured on christmas?