Posts Tagged ‘Einstein’
“Reality is merely an illusion, albeit a very persistent one”*…
In an excerpt from his new book, The Rigor of Angels: Borges, Heisenberg, Kant, and the Ultimate Nature of Reality, the estimable William Egginton explains the central mystery at the heart of one of the most important breakthroughs in physics–quantum mechanics…
For all its astonishing, mind-bending complexity– for all its blurry cats, entangled particles, buckyballs, and Bell’s inequalities– quantum mechanics ultimately boils down to one core mystery. This mystery found its best expression in the letter Heisenberg wrote to Pauli in the fevered throes of his discovery. The path a particle takes ‘only comes into existence through this, that we observe it.’ This single, stunning expression underlies all the rest: the wave/particle duality (interference patterns emerge when the particles have not yet been observed and hence their possible paths interfere with one another); the apparently absurd liminal state of Schrodinger’s cat ( the cat seems to remain blurred between life and death because atoms don’t release a particle until observed); the temporal paradox (observing a particle seems to retroactively determine the path it chose to get here); and, the one that really got to Einstein, if the observation of a particle at one place and time instantaneously changes something about the rest of reality, then locality, the cornerstone of relativity and guarantee that the laws of physics are invariable through the universe, vanishes like fog on a warming windowpane.
If the act of observation somehow instantaneously conjures a particle’s path, the foundations not only of classical physics but also of what we widely regard as physical reality crumble before our eyes. This fact explains why Einstein held fast to another interpretation. The particle’s path doesn’t come into existence when we observe it. The path exists, but we just can’t see it. Like the parable of the ball in the box he described in his letter to Schrodinger, a 50 percent chance of finding a ball in any one of two boxes does not complete the description of the ball’s reality before we open the box. It merely states our lack of knowledge about the ball’s whereabouts.
And yet, as experiment after experiment has proven, the balls simply aren’t there before the observation. We can separate entangled particles, seemingly to any conceivable distance, and by observing one simultaneously come to know something about the other–something that wasn’t the case until the exact moment of observing it. Like the beer and whiskey twins, we can maintain total randomness up to a nanosecond before one of them orders, and still what the one decides to order will determine the other’s drink, on the spot, even light-years away.
The ineluctable fact of entanglement tells us something profound about reality and our relation to it. Imagine you are one of the twins about to order a drink (this should be more imaginable than being an entangled particle about to be observed, but the idea is the same). From your perspective you can order either a whiskey or a beer: it’s a fifty-fifty choice; nothing is forcing your hand. Unbeknownst to you, however, in a galaxy far, far away, your twin has just made the choice for you. Your twin can’t tell you this or signal it in any way, but what you perceive to be a perfectly random set of possibilities, an open choice, is entirely constrained. You have no idea if you will order beer or whiskey, but when you order it, it will be the one or the other all the same. If your twin is, say, one light-year away, the time in which you make this decision doesn’t even exist over there yet. Any signals your sibling gets from you, or any signals you send, will take another year to arrive. And still, as of this moment, you each know. Neither will get confirmation for another year, but you can be confident, you can bet your life’s savings on it–a random coin toss in another galaxy, and you already know the outcome.
The riddles that arise from Heisenberg’s starting point would seem to constitute the most vital questions of existence. And yet one of the curious side effects of quantum mechanics’ extraordinary success has been a kind of quietism in the face of those very questions. The interpretation of quantum mechanics, deciding what all this means, has tended to go unnoticed by serious physics departments and the granting agencies that support them in favor of the ‘shut up and calculate’ school, leading the former to take hold mainly in philosophy departments, as a subfield of the philosophy of science called foundations of physics. Nevertheless, despite such siloing, a few physicists persisted in exploring possible solutions to the quantum riddles. Some of their ideas have been literally otherworldly.
In the 1950s, a small group of graduate students working with John Wheeler at Princeton University became fascinated with these problems and kept returning to them in late-night, sherry-fueled rap sessions. Chief among this group was Hugh Everett III, a young man with classic 1950s-style nerd glasses and a looming forehead. Everett found himself chafing at the growing no-question zone that proponents of the Copenhagen interpretation had built around their science. Why should we accept that in one quantum reality, observations somehow cause nature to take shape out of a probabilistic range of options, whereas on this side of some arbitrary line in the sand we inhabit a different, classical reality where observations meekly bow to the world out there? What exactly determines when this change takes place? ‘Let me mention a few more irritating features of the Copenhagen Interpretation,’ Everett would write to its proponents: ‘You talk of the massiveness of macro systems allowing one to neglect further quantum effects … but never give any justification for this flatly asserted dogma.’…
A fascinating sample of a fascinating book: “Quantum Mechanics,” from @WilliamEgginton via the invaluable @delanceyplace.
Further to which, it’s interesting to recall that, in his 1921 The Analysis Of Mind, Bertrand Russell observed:
What has permanent value in the outlook of the behaviourists is the feeling that physics is the most fundamental science at present in existence. But this position cannot be called materialistic, if, as seems to be the case, physics does not assume the existence of matter…
via Robert Cottrell
See also: “Objective Reality May Not Exist, Quantum Experiment Suggests” (source of the image above).
* Albert Einstein
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As we examine existence, we might spare a thought for Otto Frisch; he died on this date in 1979. A physicist, he was (with Otto Stern and Immanuel Estermann) the first to measure the magnetic moment of the proton. With his aunt, Lise Meitner, he advanced the first theoretical explanation of nuclear fission (coining the term) and first experimentally detected the fission by-products. Later, with his collaborator Rudolf Peierls, he designed the first theoretical mechanism for the detonation of an atomic bomb in 1940.
“Protons give an atom its identity, electrons its personality”*…
If the electron’s charge wasn’t perfectly round, it could reveal the existence of hidden particles– and launch a “new physics.” But, as Zack Savitsky reports, a new measurement approaches perfection…
Imagine an electron as a spherical cloud of negative charge. If that ball were ever so slightly less round, it could help explain fundamental gaps in our understanding of physics, including why the universe contains something rather than nothing.
Given the stakes, a small community of physicists has been doggedly hunting for any asymmetry in the shape of the electron for the past few decades. The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecule.
The latest results are in: The electron is rounder than that.
The updated measurement disappoints anyone hoping for signs of new physics. But it still helps theorists to constrain their models for what unknown particles and forces may be missing from the current picture…
More at “The Electron Is So Round That It’s Ruling Out Potential New Particles,” from @savagitsky in @QuantaMagazine.
* Bill Bryson
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As we ponder perfection, we might spare a thought for Jean Baptiste Perrin; he died on this date in 1942. A physicist, he studied the Brownian motion of minute particles suspended in liquids (sedimentation equilibrium), and verified Albert Einstein’s explanation of the phenomenon– thereby confirming the atomic nature of matter… for which he was awarded the Nobel Prize for Physics in 1926.
“You must not fool yourself, and you are the easiest person to fool”*…
The quest for room-temperature superconducting seems a bit like the hunt for the Holy Grail. A superconductor is a material that will transmit electricity with no resistance– thus very quickly and with no loss. (Estimates of loss in the U.S. electric grid, most of it due to heat loss from resistance in transmission, range from 5-10%; at the low end, that’s enough to power all seven Central American countries four times over.) Beyond that (already extraordinary) benefit, superconductivity could enable high-efficiency electric motors, maglev trains, low-cost magnets for MRI and nuclear fusion, a promising form of quantum computing (superconducting qubits), and much, much more.
Superconductivity was discovered in 1911, and has been the subject of fervent study ever since; indeed, four Nobel prizes have gone to scientists working on it, most recently in 2003. But while both understanding and application have advanced, it has remained the case that superconductivity can only be achieved at very low temperatures (or very high pressures). Until the mid-80s, it was believed that it could be established only below 30 Kelvin (-405.67 degrees Farenheit); by 2015, scientists had gotten that up to 80 K (-316 degrees Farenheit)… that’s to say, still requiring way too much cooling to be widely practical.
So imagine the excitement earlier this month, when…
In a packed talk on Tuesday afternoon at the American Physical Society’s annual March meeting in Las Vegas, Ranga Dias, a physicist at the University of Rochester, announced that he and his team had achieved a century-old dream of the field: a superconductor that works at room temperature and near-room pressure. Interest was so intense in the presentation that security personnel stopped entry to the overflowing room more than fifteen minutes before the talk. They could be overheard shooing curious onlookers away shortly before Dias began speaking.
The results, published in Nature, appear to show that a conventional conductor — a solid composed of hydrogen, nitrogen and the rare-earth metal lutetium — was transformed into a flawless material capable of conducting electricity with perfect efficiency.
While the announcement has been greeted with enthusiasm by some scientists, others are far more cautious, pointing to the research group’s controversial history of alleged research malfeasance. (Dias strongly denies the accusations.) Reactions by 10 independent experts contacted by Quanta ranged from unbridled excitement to outright dismissal…
Interesting if true– a paper in Nature divides the research community: “Room-Temperature Superconductor Discovery Meets With Resistance,” from @QuantaMagazine.
* Richard Feynman
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As we review research, we might pause, on Pi Day, for a piece of pi(e)…
… in celebration of Albert Einstein’s birthday; he was born on this date in 1879.
“Everything should be made as simple as possible, but not simpler.”
“‘Space-time’ – that hideous hybrid whose very hyphen looks phoney”*…
Space and time seem about as basic as anything could be, even after Einstein’s theory of General Relativity threw (in) a curve. But as Steven Strogatz discusses with Sean Carroll, the reconciliation of Einstein’s work with quantum theory is seeming to suggest that space and time might actually be emergent properties of quantum reality, not fundamental parts of it…
… we’re going to be discussing the mysteries of space and time, and gravity, too. What’s so mysterious about them?
Well, it turns out they get really weird when we look at them at their deepest levels, at a super subatomic scale, where the quantum nature of gravity starts to kick in and become crucial. Of course, none of us have any direct experience with space and time and gravity at this unbelievably small scale. Up here, at the scale of everyday life, space and time seem perfectly smooth and continuous. And gravity is very well described by Isaac Newton’s classic theory, a theory that’s been around for over 300 years now.
But then, about 100 years ago, things started to get strange. Albert Einstein taught us that space and time could warp and bend like a piece of fabric. This warping of the space-time continuum is what we experience as gravity. But Einstein’s theory is mainly concerned with the largest scales of nature, the scale of stars, galaxies and the whole universe. It doesn’t really have much to say about space and time at the very smallest scales.
And that’s where the trouble really starts. Down there, nature is governed by quantum mechanics. This amazingly powerful theory has been shown to account for all the forces of nature, except gravity. When physicists try to apply quantum theory to gravity, they find that space and time become almost unrecognizable. They seem to start fluctuating wildly. It’s almost like space and time fall apart. Their smoothness breaks down completely, and that’s totally incompatible with the picture in Einstein’s theory.
s physicists try to make sense of all of this, some of them are coming to the conclusion that space and time may not be as fundamental as we always imagined. They’re starting to seem more like byproducts of something even deeper, something unfamiliar and quantum mechanical. But what could that something be?….
Find out at: “Where Do Space, Time and Gravity Come From?, ” from @stevenstrogatz and @seanmcarroll in @QuantaMagazine.
* Vladimir Nabokov
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As we fumble with the fundamental, we might send far-sighted birthday greetings to Jocelyn Bell Burnell; she was born on this date in 1943. An astrophysicist, she discovered the first pulsar, while working as a post-doc, in 1957. She then discovered the next three detected pulsars.
The discovery eventually earned the Nobel Prize in Physics in 1974; however, she was not one of the prize’s recipients. The paper announcing the discovery of pulsars had five authors. Bell’s thesis supervisor Antony Hewish was listed first, Bell second. Hewish was awarded the Nobel Prize, along with the astronomer Martin Ryle.
A pulsar— or pulsating radio star– a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The precise periods of pulsars make them very useful tools. Observations of a pulsar in a binary neutron star system were used to confirm (indirectly) the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12. And certain types of pulsars rival atomic clocks in their accuracy in keeping time.
“A nothing will serve just as well as a something about which nothing could be said”*…
Metaphysical debates in quantum physics don’t get at “truth,” physicist and mathematician Timothy Andersen argues; they’re nothing but a form of ritual activity and culture. After a thoughtful intellectual history of both quantum mechanics and Wittgenstein’s thought, he concludes…
If Wittgenstein were alive today, he might have couched his arguments in the vocabulary of cultural anthropology. For this shared grammar and these language games, in his view, form part of much larger ritualistic mechanisms that connect human activity with human knowledge, as deeply as DNA connects to human biology. It is also a perfect example of how evolution works by using pre-existing mechanisms to generate new behaviors.
The conclusion from all of this is that interpretation and representation in language and mathematics are little different than the supernatural explanations of ancient religions. Trying to resolve the debate between Bohr and Einstein is like trying to answer the Zen kōan about whether the tree falling in the forest makes a sound if no one can hear it. One cannot say definitely yes or no, because all human language must connect to human activity. And all human language and activity are ritual, signifying meaning by their interconnectedness. To ask what the wavefunction means without specifying an activity – and experiment – to extract that meaning is, therefore, as sensible as asking about the sound of the falling tree. It is nonsense.
As a scientist and mathematician, Wittgenstein has challenged my own tendency to seek out interpretations of phenomena that have no scientific value – and to see such explanations as nothing more than narratives. He taught that all that philosophy can do is remind us of what is evidently true. It’s evidently true that the wavefunction has a multiverse interpretation, but one must assume the multiverse first, since it cannot be measured. So the interpretation is a tautology, not a discovery.
I have humbled myself to the fact that we can’t justify clinging to one interpretation of reality over another. In place of my early enthusiastic Platonism, I have come to think of the world not as one filled with sharply defined truths, but rather as a place containing myriad possibilities – each of which, like the possibilities within the wavefunction itself, can be simultaneously true. Likewise, mathematics and its surrounding language don’t represent reality so much as serve as a trusty tool for helping people to navigate the world. They are of human origin and for human purposes.
To shut up and calculate, then, recognizes that there are limits to our pathways for understanding. Our only option as scientists is to look, predict and test. This might not be as glamorous an offering as the interpretations we can construct in our minds, but it is the royal road to real knowledge…
A provocative proposition: “Quantum Wittgenstein,” from @timcopia in @aeonmag.
* Ludwig Wittgenstein, Philosophical Investigations
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As we muse on meaning, we might recall that it was on this date in 1954 that the official ground-breaking for CERN (Conseil européen pour la recherche nucléaire) was held. Located in Switzerland, it is the largest particle physics laboratory in the world… that’s to say, a prime spot to do the observation and calculation that Andersen suggests. Indeed, it’s been the site of many breakthrough discoveries over the years, maybe most notably the 2012 observation of the Higgs Boson.
Because researchers need remote access to these facilities, the lab has historically been a major wide area network hub. Indeed, it was at CERN that Tim Berners-Lee developed the first “browser”– and effectively fomented the emergence of the web.
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