Quantum weirdness: noise is spontanous (Introduction)

by BBella @, Thursday, July 14, 2016, 22:53 (2836 days ago) @ David Turell

Is quantum mechanics deterministic or totally random:
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> http://nautil.us/issue/38/noise/the-noise-at-the-bottom-of-the-universe
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> "To a physicist, perfect quiet is the ultimate noise. Silence your cellphone, still your thoughts, and muffle every kind of vibration, and you would still be left with quantum noise. It represents an indeterminacy deep within nature, bursts of static and inexplicable motions that cannot be gotten rid of, or made sense of. It seems devoid of meaning.
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> "Considering how pervasive this noise is, you might presume that physicists would have a good explanation for it. But it remains one of the great unsolved problems in science. Quantum theory is silent not just on where the noise comes from, but on how exactly it enters the world. The theory's defining equation, the Schrödinger equation, is completely deterministic. There is no noise in it at all. To explain why we observe quantum particles to be noisy, we need some additional principle
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> "For physicists in the Niels Bohr tradition, the act of observation itself is decisive. The Schrödinger equation defines a menu of possibilities for what a particle could do, but only when measured does the particle actually do anything, choosing at random from the menu. Identical particles will make different choices, causing the outcomes of fundamental processes to vary in an uncontrollable way. On Bohr's view, quantum noise cannot be explained further. It is what physicist John Wheeler called “an elementary act of creation,” with no antecedents. Genesis was not a singular event in the distant past, but an ongoing process that we bring about. We create the world by observing it.
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> "To skeptics such as Einstein, that view is both wonderfully romantic and completely incoherent. Who are “we”? What is “observing”? Physicists and philosophers have spent the better part of a century seeking a less hand-wavy explanation, taking one of two general directions. Maybe quantum noise, like the noise we encounter in daily life, has a meaning that escapes us. It may seem indeterministic, but could be produced by deterministic processes that, for whatever reason, we can't see.
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> ***
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> " In 1986, three physicists—GianCarlo Ghirardi, Alberto Rimini, and Tullio Weber—proposed that not only is quantum noise meaningless, but experimenters don't trigger it. In fact, nothing does. It shows up, completely unprompted—perhaps once every 100 million years for an individual particle.
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> "Within the interpretational debate, the GRW theory and its variants play a special role. Although they are not the only indeterministic interpretation of quantum mechanics, they are the only interpretation that exposes the indeterminism for all to see—as noise—rather than bury it at a subquantum level. GRW is also one of the few interpretations that is testable empirically. Here, at last, is a data-driven test for a debate that hails from the days of Democritus and Plato: Is the universe at its root deterministic or not?
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> "The GRW theory supposes that noise sporadically strikes particles and causes them to materialize in one of the locations open to them. This can't happen very often, or else particle behavior would deviate from the Schrödinger equation all the time. Once every 100 million years is enough, because when the blow does come, its effect is greatly amplified by quantum entanglement—the spooky interconnection of particles. A hit on one particle is felt by all those it is entangled with.
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> "GRW is a powerful theory, but none of its experimental predictions has held up so far
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> ***
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> "Determinism wouldn't strictly eliminate the noise, but merely relocate it. Through the laws of physics, we could trace the origins of each burst of noise—it wouldn't appear out of nowhere, as in the GRW theory, but would occur because particles had been on certain trajectories. In principle, we could unwind those trajectories back to the initial conditions of the universe, which would consist of all the noise of history, lumped together. Whatever the source of noise, it is the raw material of the world, sculpted into rich patterns through processes of evolution and emergence.
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> "In the lab, physicists seek to strip away the noise of the world and expose its simple core. But at some deeper level, they strip away signal to expose noise, and pivot a foundational question on it. So is noise really signal? “To God all is signal,” the University of Southern California engineering and law professor Bart Kosko once wrote. If anything, though, the opposite is true: To God all is noise; only to man, who constructs his own meaning, is anything a signal at all."
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> Comment: At the basis of the universe is still total confusion. Perhaps we are not ever to solve the mystery. Is this God's purpose?-To me, this is not total confusion, but what I was alluding to and hoping to find a path of discussion about this, and its implications, when I first showed up here those many years ago. Not surprising, my mind is not as clear about it now, but the implications are just as real.


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