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Physicists Reverse Time Using Quantum Computer (phys.org)
fahrbot-bot shares a report from Phys.Org: Researchers from the Moscow Institute of Physics and Technology teamed up with colleagues from the U.S. and Switzerland and returned the state of a quantum computer a fraction of a second into the past. They also calculated the probability that an electron in empty interstellar space will spontaneously travel back into its recent past. The study is published in Scientific Reports.
Quantum physicists from MIPT decided to check if time could spontaneously reverse itself at least for an individual particle and for a tiny fraction of a second. That is, instead of colliding billiard balls, they examined a solitary electron in empty interstellar space. "Suppose the electron is localized when we begin observing it. This means that we're pretty sure about its position in space. The laws of quantum mechanics prevent us from knowing it with absolute precision, but we can outline a small region where the electron is localized," says study co-author Andrey Lebedev from MIPT and ETH Zurich. The physicist explains that the evolution of the electron state is governed by Schrodinger's equation. Although it makes no distinction between the future and the past, the region of space containing the electron will spread out very quickly. That is, the system tends to become more chaotic. The uncertainty of the electron's position is growing. This is analogous to the increasing disorder in a large-scale system -- such as a billiard table -- due to the second law of thermodynamics.
"However, Schrodinger's equation is reversible," adds Valerii Vinokur, a co-author of the paper, from the Argonne National Laboratory, U.S. "Mathematically, it means that under a certain transformation called complex conjugation, the equation will describe a 'smeared' electron localizing back into a small region of space over the same time period." Although this phenomenon is not observed in nature, it could theoretically happen due to a random fluctuation in the cosmic microwave background permeating the universe. The team set out to calculate the probability to observe an electron "smeared out" over a fraction of a second spontaneously localizing into its recent past. It turned out that even across the entire lifetime of the universe -- 13.7 billion years -- observing 10 billion freshly localized electrons every second, the reverse evolution of the particle's state would only happen once. And even then, the electron would travel no more than a mere one ten-billionth of a second into the past. The researchers then attempted to reverse time in a four-stage experiment by observing the state of a quantum computer made of superconducting qubits, instead of an electron. The researchers "found that in 85 percent of the cases, the two-qubit quantum computer returned back into the initial state," reports Phys.Org. "When three qubits were involved, more errors happened, resulting in a roughly 50 percent success rate. According to the authors, these errors are due to imperfections in the actual quantum computer. As more sophisticated devices are designed, the error rate is expected to drop."
Quantum physicists from MIPT decided to check if time could spontaneously reverse itself at least for an individual particle and for a tiny fraction of a second. That is, instead of colliding billiard balls, they examined a solitary electron in empty interstellar space. "Suppose the electron is localized when we begin observing it. This means that we're pretty sure about its position in space. The laws of quantum mechanics prevent us from knowing it with absolute precision, but we can outline a small region where the electron is localized," says study co-author Andrey Lebedev from MIPT and ETH Zurich. The physicist explains that the evolution of the electron state is governed by Schrodinger's equation. Although it makes no distinction between the future and the past, the region of space containing the electron will spread out very quickly. That is, the system tends to become more chaotic. The uncertainty of the electron's position is growing. This is analogous to the increasing disorder in a large-scale system -- such as a billiard table -- due to the second law of thermodynamics.
"However, Schrodinger's equation is reversible," adds Valerii Vinokur, a co-author of the paper, from the Argonne National Laboratory, U.S. "Mathematically, it means that under a certain transformation called complex conjugation, the equation will describe a 'smeared' electron localizing back into a small region of space over the same time period." Although this phenomenon is not observed in nature, it could theoretically happen due to a random fluctuation in the cosmic microwave background permeating the universe. The team set out to calculate the probability to observe an electron "smeared out" over a fraction of a second spontaneously localizing into its recent past. It turned out that even across the entire lifetime of the universe -- 13.7 billion years -- observing 10 billion freshly localized electrons every second, the reverse evolution of the particle's state would only happen once. And even then, the electron would travel no more than a mere one ten-billionth of a second into the past. The researchers then attempted to reverse time in a four-stage experiment by observing the state of a quantum computer made of superconducting qubits, instead of an electron. The researchers "found that in 85 percent of the cases, the two-qubit quantum computer returned back into the initial state," reports Phys.Org. "When three qubits were involved, more errors happened, resulting in a roughly 50 percent success rate. According to the authors, these errors are due to imperfections in the actual quantum computer. As more sophisticated devices are designed, the error rate is expected to drop."
And he can actually go to MIT and study statistics, like for really-real instead of lying 5 sigma insignificantly about it on slashdot, like a punk might do. The Lori Loughlin of statistics, stolen valor MIT, ridiculous. R = 0
then why did he have to steal the plutonium from libyians?
The experiment was about reversing entropy, not actually reversing the flow of time.
That is interesting enough, why make up stupid headlines?
Same thing happened a ways back about some chemist unboiling an egg, which some copywriters (not linked article) tried to make it sound like time was being reversed.
They did not "send it back in time" anymore than the antimatter travels back in time.
If time was a thermodynamic phenomenon, why doesn't shit get younger when you put it in the fridge?
>> The physicist explains that the evolution of the electron state is governed by Schrodinger's equation.
They reversed a calculation on a quantum computer. Time was moving forward throughout the entire experiment.
Maybe some part of their algorithm might be useful somehow, but overall it seems like they were wasting time rather than reversing it.
This doesn't prove time reversal, it show a quantum computer can unreliably implement the Undo-Redo pattern.
1 in 10 billion in 13.7 billions years...
which should explain and predict the results seen. This is metastability and not time reversal.
Somebody tell Cher!
Slashdot appears to attract these people.
I thought time evolution in quantum mechanics was given by unitary operators, which are always invertible. What's so interesting?
I notice you omitted two things:
1. A defense of this 'reverse time' claim
2. A logical disprove of my claim.
Really, its sad, they've disproved Schrodinger, that's big news, big science, but that's not where the money is at. Congress science budget approved $1 billion for quantum conputing research (sic), and if you want to get a slice of that research fee, you have to suspend a little disbelief and pretend time is being reversed.
Without Schrodinger, the electron isn't in all places till detected and the quantum conputer isn't testing all solutions to find the optimal one. Poof there goes the budget and there goes the funding with it.
I reverse the time on my computer all the time and it's not a quantum computer.
"in 85 percent of the cases, the two-qubit quantum computer returned back into the initial state," ... According to the authors, these errors are due to imperfections in the actual quantum computer.
Maybe the amazing headline result is due to one of these errors, rather than the null hypothesis being due to errors?
Corruption is convincing someone that the selfless ideal is the same as their selfish ideal.
.... and yet the electric universe bullshit is still wrong, and Einstein was right.
Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
nothing to defy the laws of physics, especially and including time travel
Politics is Treachery, Religion is Brainwashing
This isn't reversing time, it's zeroing bits.
Make Time Travel Great Again
Much better than the Democrat's desire for the 1850s.
How DARE you leave the thought plantation!
I can't believe it. We finally have a working time machine. It's fantastic. Amazing. I don't know who to thank first... When will I be able to purchase one for my home, for my daily walks which have in recent years become implausible due to the destruction of these once-idyllic neighbourhoods?!
I had read the original article. They did not actually reverse time. What they did was cause events that normally only go one way in time to go the other way: e.g., breaking an egg - one can't cause an egg to re-assemble. Well, they did, so to speak. But it did so in the forward time direction.
... why Deja Vu happens...
The electron is not moving back in time. It is recreating a past state, but in the present time frame. It is not possible to actually measure backwards time travel without the observer also moving back in time. These are my thoughts on the subject.
I'm always doing stuff over and over again.
It always makes me feel like I am time traveling.
Is this accomplishment an implementation of reversible computing?
Decentralization: the brief interval between the decline of one centralized regime and rise of another.
These will have been my thoughts on the subject.
FTFY
The convention on Time Travel will be held last week. Tickets went on sale next month. Get yours yesterday before they run out!
Great civilizations have lived and died on false theories. Don't mess up mine with a few facts.
I came here to say that phase conjugation is not time reversal but I thought about it some more and there are limited ways you might call it pseudo time reversal.
Phase conjugation of a light wave is old stuff. When you do it reverses the direction a shaped wavefront propagates. Since the argument of a wave function f(k*z-w*t) goes backwards when you change the sign on t it's mathematically the same as making time negative. So the wave goes back to where it came from. Notably if it went through phase distorting media then the distortion is not doubled but actually is undone leaving the wave just as it was on the way out.
However if the media was attenuating the wave is not magically amplified on the way back!
So it's not really sending it back in time. It's just phase reversal or conjugation .
The same thing happens in NMR and things like Rabi frequencies. And photon echos.
The same will be true in QM. All they did was created a photon echo.
Except this is with matter not photons so it's pretty banned cool and you don't need to make it sound cooler by sayin it went backward in time.
Keeping matter coherent enough to phase conjugate us aswesome!!!
But I'll note how you could actually time reverse. That would require making the whole container phase conjugate. If we phase conjugated a photon and an attenuating medium the the photon would be amplified so really time reversed!
Some drink at the fountain of knowledge. Others just gargle.
Have you observed oscillation of matter? Is an electron charged? Is a proton charged? Is a neutron observed to contain charges? So there would be an oscillating electric field.
And if you've only ever made electric fields using electrons you know oscillate, then all the field theory is actually a theory of an oscillating electric field.
And if you substituted a +ve charge in place of the -ve charge of the electron, would it dance the opposite way in such a field? Yeh.
Yeh, so what you know as electric was F oscillation in-phase and F oscillation out-of-phase.
When the penny drops its a real duh moment. Einstein is dead and cannot save you from the duh moment. Sorry.
Then design an experiment to prove this and become world famous. Riiiiiiiiiiiiiiiiiiiiiight...that's what I thought...Einstein's theories still keep holding up to experiments long after his death. Also, you are complaining about things that people other than Einstein came up with but then name dropping Einstein. That's weird...
I can't wait to see if this was a IEEE floating point rounding problem.
Democrat's don't want to carry us back then. There were no social programs then (it's a wonder anybody survived).
No. They want to transport us physically....to Russia...so they can have their full-fledged socialism.
Aah, change is good. -- Rafiki
Yeah, but it ain't easy. -- Simba
There were no social programs then (it's a wonder anybody survived).
Actually, there were social programs in the 1850s, in the form of jobs programs that came out of...
Reconstruction
Transcontinental railroad
Expanding the military
Republicans today like to whine about big government, except they forgot that it was the party of Lincoln that expanded government greatly in the Civil War and kept it that way after it ended. This paved the way to the Progressive movement.
It was actually just ntpd!
Naive interpretation or summary.
This is like trying to drive in reverse to spin back the odometer. Even if it did spin back, it doesn't mean that the car is magically newer again.
A record player arm plays the record and returns to the starting position. Time was reversed!
A wheel turns one full revolution and returns to the original orientation. Time was reversed!
A door opens and then closes. Clearly, time has gone backwards!
I order a drink in a bar, drink it, and the waiter refills the glass. Whoa, mysterioso Jules Verne stuff going on man!
Yeah, probably not the same thing as this experiment, but the point remains. Calling this 'time travel' is uber-Dumb.