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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: 22390
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 # 15.
#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.
It detected the collapse under certain very artificial conditions. And keep in mind that a probability wave is only a mathematical construct for us to measure and discuss the likelihood of an outcome. In reality, there is no such thing as a "probability wave" of any sort. It's just how we choose to conceptualize and discuss the concept (which may or may not be helpful to progress in physics). Ever asked yourself why there are no practical applications of such science, why we seem to make little progress of any kind in quantum physics? Or even the existence of dark matter and (especially) dark energy? 100 years from now, I think people will look at our misunderstandings of the outcome of double-slit and similar experiments as rather quaint, humorous even. Have you considered that a double-slit experiment is nothing more than a special case in physics and not some fundamental principle of the universe? Perhaps these double-slit experiments cannot achieve any meaningful progress in theoretical physics because we are engaging in double-slit experiments and observing (or not observing) the results! What quantum physics needs is a few more Feynmans to clear out the babble and clutter and make some meaningful progress.
#17. To: Tooconservative (#15)
When you can't understand something, simply create antimatter to explain it. They did that with black holes -- which nothing can escape, even light. Well, Hawking radiation can. What is Hawking radiation? Well, particles and antiparticles are created outside the event horizon. One particle falls into the black hole and the other escapes as Hawking radiation. Ta-da!
Yes, and the answer I have come up with is that there are not really four fundamental forces, there is only one: the expansion of things, expressed in two spaces: atomic and subatomic. Gravity as such - force at a distance - does not exist. There is the surface acceleration of expanding objects (this is why gravity cuts off at the edge of the atmosphere, when there is nothing more to act as a piston pushing up on the bottom of the fuselage of things. There are ways to test this, and there are real physical effects of this that can be seen in the world, but it's very subtle. Einstein was essentially correct when he observed that, to a man in a box, acceleration upwards and gravity feel like the same thing. That's because they ARE the same thing. Things that orbit each other are really moving in tandem in a corkscrew through space, and the orbital distance is the distance at which their expansion towards each other is cancelled out by their velocity. It's difficult to see, because whatever you use to measure with ALSO expands, and mass remains constant. Anyway, I don't feel like an argument.
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."
#15. To: misterwhite (#13)
(Edited)
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.
In this Feynman diagram, an electron and a positron annihilate, producing a photon (represented by the blue sine wave) that becomes a quark–antiquark pair, after which the antiquark radiates a gluon (represented by the green helix).
Replies to Comment # 15. "What quantum physics needs is a few more Feynmans to clear out the babble ..."
#30. To: Tooconservative (#15)
Ever asked yourself why there are no practical applications of such science, why we seem to make little progress of any kind in quantum physics? Or even the existence of dark matter and (especially) dark energy?
End Trace Mode for Comment # 15.
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