• Scientists ‘reverse motherfucking time’ with quantum computer in study
    36 replies, posted
https://www.independent.co.uk/life-style/gadgets-and-tech/news/time-reverse-quantum-computer-science-study-moscow-a8820516.html Sorry I had to add on to the title because of how interesting it is Study: https://arxiv.org/pdf/1712.10057.pdf
So what are the implications of this? "Just" better quantum computing or does it have some grander impact on our understanding of physics itself?
yeah ok I understand some of the words in that paper
But how does it work?
From what I understand it has very little to do with the traditional notion of time at all, but rather reversing some chaotic system to a previous state.
Someone correct me here. They didn't reverse time, they inverted entropy, which is interpreted as going backwards in time? The idea of going to the past sounds at least practically impossible, we don't see people randomly popping out of nowhere. Space time must have some means of protection on the preservation of information and causality. And is it possible for time to have more than 1 dimension?
Even if it isn't literally reversing time, isn't reversing/inverting entropy really big in and of itself? I'm not too well versed on these sorts of shenanigans.
Reversal of entropy when?
What was accomplished in terms of quantum computing is definitely interesting, but the simple concept of bringing something from chaos back to order is literally the most banal thing I could think of. It'd be as if I knocked over a stack of bricks, rebuilt it and claimed that I "reversed time". Sensationalism of the absolute highest degree.
Maybe we can use it to make our sun not explode in a few billion years?
Yeah but imagine that you can reduce entropy on, like, your leftovers from a restaurant so they're as good as when you first took them home. of course the actual experiment is way more limited than that The scientists found that, working with just two qubits, “time reversal” was achieved with a success rate of 85 per cent. When three qubits were involved more errors occurred, resulting in a 50 per cent success rate. I don't actually know what the implications of this are and how it would be useful.
This has absolutely nothing to do with reversing time. What they've managed to do is chaotically randomize QBits and then create a program on a quantum computer that returns them to their original state, likely with an algorithm of some sort. Sensationalist PopSci "Science is so cool!!!!!!!" articles drive me insane
It's not reducing entropy of the qbits without external energy input, therefore it doesn't actually reduce the entropy in the universe. This much I can gather. While there is a very low probability of entropy lowering by pure chance in a closed system, this is not what's happening here. I have to admit though that I have trouble understanding the implications of the paper myself, as it involves highly advanced linear algebra and statistics. I'm assuming that the problem of bringing the qbits back into their original state used to be a hard problem before this breakthrough, someone correct me if I'm wrong.
I was hoping that title was a technical description.
Be careful, I've heard it can be painful https://media.giphy.com/media/QfsvGWS6EHwwA8IJFG/giphy.gif
God science journalism sucks
"Cosmic AC," said Man, "How may entropy be reversed?" The Cosmic AC said, "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."
Wow we are one step closer to makeing code Lyoko a reality.
So, reversing a hash operation?
Born to late to explore the world, too early to explore the stars, just in time to reverse the eventual heat death of the universe.
Unlocking the ability to save and load your consciousness?
Also known as beer.
A better analogy would be being able to find a knocked over stack of bricks and then being able to completely re-construct the form of the bricks before they were knocked down, without knowing what they used to be.
Theoretically going to the past would be possible. There's several ways to do it, most promisingly using a space-time tunnel aka a wormhole, setting one end in a specific place and then just waiting a bit and putting the other end somewhere else, but there's also strange properties we've never explored fully like how anti-matter can be represented as normal matter but with a negative sign in the time dimension. As for the time having more dimensions thing, theoretically yes, but we've found no evidence for it other than some mathematics that imply there are multiple time dimensions. Then again, we haven't found any evidence for more spatial dimensions than the 3 we know of other than some very indirect evidence from the Large Hadron Collider so that's not exactly out of the question.
This doesn't work, I don't remember the exact reason but it's something like the fact that it creates an infinite feedback loop of radiation that causes a paradox and makes the wormhole instantly collapse before anything can go through it.
Makes sense, but a time traveler can dream...
Now i'm trying to imagine what would the world be if "time"(tm) and "entropy" was reversed, in a physical sense, meaning that instead of seeking low energy states, everything seeks high energy states. This has nothing to do with folk concept of going backwards in time, like becoming younger and going to see dinosaurs, but more like physics being broken. I would think that you can cool down hot objects by placing even hotter object near it, and the hotter something is, the darker it becomes. Like sun would appear as black dot against somewhat illuminated sky. Another oddity would be that elements heavier than iron would be subject for fusion, and lighter ones favoring fission, and many radioactive elements becoming stable and vice versa. Same for many molecular reactions being reversed. Imagining reversed entropy is not easy, i constantly find contradictions on how things would appear, but for one thing i'm fairly sure; instead of slowly going towards heat death of the universe, we would rapidly go towards point where all the energy of universe is concentrated on singe location.
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