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Title: Physicists manage to 'breed' Schrodinger's cat in breakthrough that could help explain the quantum world
Source:
Daily Mail Online
URL Source: http://www.dailymail.co.uk/sciencet ... -s-cat-breakthrough-study.html
Published: May 2, 2017
Author: Cheyenne MacDonald
Post Date: 2017-05-02 07:39:35 by cranky
Keywords: None
Views: 22392
Comments: 75
Scientists have developed a way to 'breed' Schrodinger's hypothetical cat in a breakthrough experiment that could bridge the gap between the quantum and the visible - or classical - worlds. The cat in the famous thought experiment can be alive and dead at the same time, in a quantum phenomenon known as superposition. But, whether this effect translates to larger objects has long remained a mystery. Physicists have now created a way to amplify pairs of classical states of light to generate 'enlarged' cats, in effort to uncover the limit (if there is one) of the quantum world. 'One of the fundamental questions of physics is the boundary between the quantum and classical worlds,' says CIFAR Quantum Information Science Fellow Alexander Lvovsky. 'Can quantum phenomena, provided ideal conditions, be observed in macroscopic objects? 'Theory gives no answer to this question – maybe there is no such boundary. 'What we need is a tool that will probe it.' In the new experiment, the researchers 'bred' the physical analogue of the Schrodinger cat. This, in this case, is the superposition of two coherent light waves, in which the fields of the electromagnetic waves point in opposite directions at once. Based on an idea first proposed over a decade ago by researchers in Australia, the team bred these states to create optical 'cats' of higher amplitudes. 'In essence, we cause interference of two 'cats' on a beam splitter,' said Anastasia Pushkina, co-author and University of Calgary graduate student. 'This leads to an entangled state in the two output channels of that beam splitter. 'In one of these channels, a special detector is placed. 'In the event this detector shows a certain result, a 'cat' is born in the second output whose energy is more than twice that of the initial one.' Doing this, the researchers converted a pair of negative squeezed 'cats' of amplitude 1.15 to a single positive 'cat' of amplitude 1.85. Doing this, the researchers converted a pair of negative squeezed 'cats' of amplitude 1.15 to a single positive 'cat' of amplitude 1.85. Entangled particles are illustrated above Over the course of the experiment, they generated several thousand of these enlarged cats. According to the researchers the experiment has implications for future work in quantum communication, teleportation, and cryptography. 'It is important that the procedure can be repeated: new 'cats' can, in turn, be overlapped on a beam splitter, producing one with even higher energy, and so on,' says lead author Demid Sychev, a graduate student from the Russian Quantum Center and the Moscow State Pedagogical University. 'Thus, it is possible to push the boundaries of the quantum world step by step, and eventually to understand whether it has a limit.' Schrödinger's cat is a thought experiment created by Austrian physicist Erwin Schrödinger in 1935. In the hypothetical experiment a cat is placed in a sealed box next to a radioactive sample, a Geiger counter, and a bottle of poison. The observer cannot know whether or not an atom of the substance has decayed, and consequently, cannot know whether the vial has been broken, releasing the poison and killing the cat, until the box is opened. This means the cat is both dead and alive inside the box, a mixture of both states, until the box is opened. 'One of the fundamental questions of physics is the boundary between the quantum and classical worlds,' says CIFAR Quantum Information Science Fellow Alexander Lvovsky. 'Can quantum phenomena, provided ideal conditions, be observed in macroscopic objects? 'Theory gives no answer to this question – maybe there is no such boundary. 'What we need is a tool that will probe it.' In the new experiment, the researchers 'bred' the physical analogue of the Schrodinger cat. This, in this case, is the superposition of two coherent light waves, in which the fields of the electromagnetic waves point in opposite directions at once. Based on an idea first proposed over a decade ago by researchers in Australia, the team bred these states to create optical 'cats' of higher amplitudes.
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Begin Trace Mode for Comment # 25.
#1. To: cranky (#0)
No. Quantum phenomena ride on probability waves. Those waves collapse upon observation. The double-slit experiment proves this. A coin can be heads or tails -- until you look at it.
Poor cat
Maybe. Maybe not.
Maybe. Maybe not. He is in two states at the same time. I think this thread is promising. Cultural learnings of the quantum world.
No. This is a common misconception by people who don't understand the issue. The cat is only potentially in one of two states and physicists use this duality to solve certain classes of problems in physics. The cat either is or is not dead. But for the larger purposes of theory, you must treat it as though it is in an undetermined state. There is a fundamental vanity to the common misconception of Schrodinger. We presume that the state of something actually changes depending on whether a human observer is watching. But, if that is true, is Schrodinger's cat still either dead or alive depending on whether another cat sees it? How about a dog? Of course, it is nonsense. Anything that grants to mere human observation something akin to godlike powers is nothing but nonsense. And any physicist would tell you this, that you are greatly misrepresenting Schrodinger's work and that his cat is, indeed, either alive or dead at any given moment in space-time. But for theoretical constructs and calculation, we do need to assume it is both alive and dead at any given time so we can achieve higher-order theoretical constructs without having to worry about whether some guy's cat is alive or dead inside a box. Given my opinion, you can imagine how annoyed I get when people pose philosophical questions like "If a tree falls in a forest and no one is around to hear it, does it make a sound?" It's more nonsense like the common misunderstandings of non-physicists about Schrodinger. Again, the tree has fallen and it has made the same sound regardless of whether a human being heard it or not. Nevertheless, physicists do discuss this issue. I personally disbelieve this legend. Both Bohr and Einstein were too smart to take such a question seriously. Neither believed that, as a matter of physics, that human beings were the center of the universe and of reality itself. It's nothing but arrogance (and weak-minded lazy philosophy) to think otherwise.
In the double-slit experiment, setting up a detector with a recorder at the slits forced the collapse of the probability wave and there was no interference.
As always, you should ask: WWFD (What Would Feynman Do)? (see RF at 09:00 for the discussion of the two slits experiment) Since I'm lazy and stupid, I'll just stick with Feynman. It's the safe bet. : ) It is worth recalling that Bohr almost drove himself insane trying and failing to resolve the contradictions of quantum physics. Feynman fixed those problems and revolutionized (virtually invented) modern quantum mechanics. Not Bohr or Einstein who both applied themselves to the same problems.
It was a good presentation as far as it went. But if electrons (or photons) were fired one at a time, they would still create an interference pattern and he had no explanation for that.
I think he did. Wiki: Feynman, Richard P.; Robert B. Leighton; Matthew Sands (1965). The Feynman Lectures on Physics, Vol. 3. Obviously, Feynman did think about the double-slit experiment a great deal. But his greatness was how much he advanced the entire field through practical theoretical work, especially his diagrams. Feynman had a camper in the Seventies that he had painted with his diagrams, just for fun. He was a little quirky. While traveling with the family, they came out of a restaurant. A university physics student was blinking at the van as they came out and then said to them, "Hey, why is your van covered with Feynman diagrams?". Mrs. Feynman said, "Because we're the Feynman's." and they jumped in the van and drove off. In recent years, the van was brought out of storage and restored.
His presentation showed that photons and electrons behaved like waves until they were tampered with by observation. Then they acted like particles. But there are experiments that negate these effects, demonstrating that observation alone collapses the probability wave.
#26. To: misterwhite (#25)
I always thought that there is no probability collapse at all. There are particles that can behave as waves in some circumstances. Or maybe waves that can behave as particles. : ) Of course, this is the sort of thing that makes frustrated science guys try to cheat by inventing stuff like wavicles.
Top • Page Up • Full Thread • Page Down • Bottom/Latest"Can quantum phenomena, provided ideal conditions, be observed in macroscopic objects?"
#2. To: misterwhite (#1)
#3. To: A Pole (#2)
Poor cat
#5. To: misterwhite, Deckard, Vicomte13, ConservingFreedom, Willie Green, hondo68, calcon, TooConservative (#3)
Poor cat
#6. To: A Pole (#5)
He is in two states at the same time.
Albert Einstein is reported to have asked his fellow physicist and friend Niels Bohr, one of the founding fathers of quantum mechanics, whether he realistically believed that 'the moon does not exist if nobody is looking at it.' To this Bohr replied that however hard he (Einstein) may try, he would not be able to prove that it does, thus giving the entire riddle the status of a kind of an infallible conjecture—one that cannot be either proved or disproved.
#13. To: Tooconservative (#6)
"We presume that the state of something actually changes depending on whether a human observer is watching."
#19. To: misterwhite (#13)
(Edited)
In the double-slit experiment,...
#23. To: Tooconservative (#19)
#24. To: misterwhite (#23)
It was a good presentation as far as it went. But if electrons (or photons) were fired one at a time, they would still create an interference pattern and he had no explanation for that.
The double-slit experiment (and its variations) has become a classic thought experiment, for its clarity in expressing the central puzzles of quantum mechanics. Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results, Richard Feynman called it "a phenomenon which is impossible […] to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery [of quantum mechanics]." 
#25. To: Tooconservative (#24)
"Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results"
Replies to Comment # 25. But there are experiments that negate these effects, demonstrating that observation alone collapses the probability wave.
End Trace Mode for Comment # 25.
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