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Posts Tagged ‘quantum mechanics

“The true sign of intelligence is not knowledge but imagination”*…

 

Perhaps Arthur C. Clarke was being uncharacteristically unambitious. He once pointed out that any sufficiently advanced technology is going to be indistinguishable from magic. If you dropped in on a bunch of Paleolithic farmers with your iPhone and a pair of sneakers, you’d undoubtedly seem pretty magical. But the contrast is only middling: The farmers would still recognize you as basically like them, and before long they’d be taking selfies. But what if life has moved so far on that it doesn’t just appear magical, but appears like physics?

After all, if the cosmos holds other life, and if some of that life has evolved beyond our own waypoints of complexity and technology, we should be considering some very extreme possibilities. Today’s futurists and believers in a machine “singularity” predict that life and its technological baggage might end up so beyond our ken that we wouldn’t even realize we were staring at it. That’s quite a claim, yet it would neatly explain why we have yet to see advanced intelligence in the cosmos around us, despite the sheer number of planets it could have arisen on—the so-called Fermi Paradox…

Caleb Scharf on the possibility that alien life could be so advanced it is indistinguishable from physics: “Is Physical Law an Alien Intelligence?

For a very different perspective (albeit, one seemingly rooted in a more narrowly-defined understanding of “life”), see “A Key Evolutionary Step May Mean Intelligent Alien Life Doesn’t Exist in the Universe.”

* Albert Einstein

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As we think through the thought experiment, we might send uncertain birthday greetings to Werner Karl Heisenberg; he was born on this date in 1901.  A theoretical physicist, he made made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, superconductivity, cosmic rays, and subatomic particles.  But he is most widely remembered as a pioneer of quantum mechanics and author of what’s become known as the Heisenberg Uncertainty Principle.  Heisenberg was awarded the Nobel Prize in Physics for 1932 “for the creation of quantum mechanics.”

During World War II, Heisenberg was part of the team attempting to create an atomic bomb for Germany– for which he was arrested and detained by the Allies at the end of the conflict.  He was returned to Germany, where he became director of the Kaiser Wilhelm Institute for Physics, which soon thereafter was renamed the Max Planck Institute for Physics. He later served as president of the German Research Council, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, and president of the Alexander von Humboldt Foundation.

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“There is nothing more wonderful than a list, instrument of wondrous hypotyposis”*…

 

Da Vinci would carry around a notebook, where he would write and draw anything that moved him. “It is useful,” Leonardo once wrote, to “constantly observe, note, and consider.” Buried in one of these books, dating back to around the 1490s, is a to-do list. And what a to-do list…

Check it out (if not off) at “Leonardo Da Vinci’s To Do List (Circa 1490) Is Much Cooler Than Yours.”

* Umberto Eco, The Name of the Rose

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As we prioritize prioritization, we might spare a thought for Erwin Rudolf Josef Alexander Schrödinger; he died on this date in 1961.  A physicist best remembered in his field for his contributions to the development of quantum mechanics (e.g., the Schrödinger equation), and more generally for his “Schrödinger’s cat thought experiment– a critique of the Copenhagen interpretation of quantum mechanics– he also wrote on philosophy and theoretical biology.  Indeed, both James Watson, and independently, Francis Crick, co-discoverers of the structure of DNA, credited Schrödinger’s What is Life? (1944), with its theoretical description of how the storage of genetic information might work, as an inspiration.

It seems plain and self-evident, yet it needs to be said: the isolated knowledge obtained by a group of specialists in a narrow field has in itself no value whatsoever, but only in its synthesis with all the rest of knowledge and only inasmuch as it really contributes in this synthesis toward answering the demand, “Who are we?”

– from Science and Humanism, 1951

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Written by LW

January 4, 2017 at 1:01 am

“Nothing puzzles me more than time and space; and yet nothing troubles me less”…

 

Time crystals– crystals that break both spacial and temporal symmetry– were first predicted by Nobel laureate Frank Wilczek in 2012… and were widely deemed amusing, but impossible (e.g., here).  Now researchers have created time crystals for the first time and say they could one day be used as quantum memories… and might help reconcile Quantum Mechanics with the Theory of Relativity.

Bend your mind at “Physicists Create World’s First Time Crystal,” also here and here (source of the photo above).

* Charles Lamb

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As we ponder Einstein’s insistence that time is an illusion, we might send well-structured birthday greetings to Pierre-Gilles de Gennes; he was born on this date in 1932.  A French physicist, he was awarded the 1991 Nobel Prize for Physics for “discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers.”  He described mathematically how, for example, magnetic dipoles, long molecules or molecule chains can under certain conditions form ordered states, and what happens when they pass from an ordered to a disordered state.  Such changes of order occur when, for example, a heated magnet changes from a state in which all the small atomic magnets are lined up in parallel to a disordered state in which the magnets are randomly oriented.  Later, he was concerned with the physical chemistry of adhesion.

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Written by LW

October 24, 2016 at 1:01 am

Playing at life…

 

For years both scientists and science fiction writers have suggested that a sufficiently advanced civilisation could– and thus would– create a simulated universe.  And since simulations beget simulations (within simulations, within simulations, etc., etc.), there would ultimately be many more simulated universes than real ones…  meaning that it would be more likely than not that any one universe– say, ours– is artificial.

Silas Beane, working with a team at the University of Bonn says he have evidence this may be true.  The Physics arXiv Blog at Technology Review explains:

 

First, some background. The problem with all simulations is that the laws of physics, which appear continuous, have to be superimposed onto a discrete three dimensional lattice which advances in steps of time.

The question that Beane and co ask is whether the lattice spacing imposes any kind of limitation on the physical processes we see in the universe. They examine, in particular, high energy processes, which probe smaller regions of space as they get more energetic

What they find is interesting. They say that the lattice spacing imposes a fundamental limit on the energy that particles can have. That’s because nothing can exist that is smaller than the lattice itself.

So if our cosmos is merely a simulation, there ought to be a cut off in the spectrum of high energy particles.

It turns out there is exactly this kind of cut off in the energy of cosmic ray particles,  a limit known as the Greisen–Zatsepin–Kuzmin or GZK cut off.

This cut-off has been well studied and comes about because high energy particles interact with the cosmic microwave background and so lose energy as they travel  long distances.

But Beane and co calculate that the lattice spacing imposes some additional features on the spectrum. “The most striking feature…is that the angular distribution of the highest energy components would exhibit cubic symmetry in the rest frame of the lattice, deviating significantly from isotropy,” they say.

In other words, the cosmic rays would travel preferentially along the axes of the lattice, so we wouldn’t see them equally in all directions.

That’s a measurement we could do now with current technology. Finding the effect would be equivalent to being able to to ‘see’ the orientation of lattice on which our universe is simulated…

Read the whole mind-blowing story (including some comforting caveats) at “The Measurement That Would Reveal The Universe As A Computer Simulation” (and find Beane’s paper here).

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As we wonder if there’s a “reset” button, we might spare a thought for the extraordinary Erwin Rudolf Josef Alexander Schrödinger; he died on this date in 1961.  A physicist best remembered in his field for his contributions to the development of quantum mechanics (e.g., the Schrödinger equation), and more generally for his “Schrödinger’s cat thought experiment– a critique of the Copenhagen interpretation of quantum mechanics– he also wrote on philosophy and theoretical biology.  Indeed, both James Watson, and independently, Francis Crick, co-discoverers of the structure of DNA, credited Schrödinger’s What is Life? (1944), with its theoretical description of how the storage of genetic information might work, as an inspiration.

It seems plain and self-evident, yet it needs to be said: the isolated knowledge obtained by a group of specialists in a narrow field has in itself no value whatsoever, but only in its synthesis with all the rest of knowledge and only inasmuch as it really contributes in this synthesis toward answering the demand, “Who are we?”

– from Science and Humanism, 1951

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Written by LW

January 4, 2013 at 1:01 am

News that isn’t…

From corrections…

… to photos…

…to typos…

… readers will find the backstories to these gaffes and myriad others at Poynter’s “The best (and worst) media errors and corrections of 2012.”

Special Bonus:  Jim Romenesko’s Headline of the Year: “Maneater: Hall Bitten by Oates.”

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As we fixate on fact-checking, we might recall that this is the birthday of quantum physics: it was on this date in 1900 that Max Planck published his study of the effect of radiation on a “blackbody” substance, demonstrating that in certain situations energy exhibits the characteristics of physical matter– something unthinkable at the time– and suggesting that energy exists in discrete packets, which he called “quanta”… thus laying the foundation on which he, Einstein, Bohr, Schrodinger, Dirac, and others built our modern understanding of physics.

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Written by LW

December 14, 2012 at 1:01 am

To See What Condition My Condition Was In…

Could Quantum Mechanics be wrong?

The philosophical status of the wavefunction — the entity that determines the probability of different outcomes of measurements on quantum-mechanical particles — would seem to be an unlikely subject for emotional debate. Yet online discussion of a paper claiming to show mathematically that the wavefunction is real has ranged from ardently star-struck to downright vitriolic since the article was first released as a preprint in November 2011.

The paper, thought by some to be one of the most important in quantum foundations in decades, was finally published last week in Nature Physics (M. F. Pusey, J. Barrett & T. Rudolph Nature Phys. http://dx.doi.org/10.1038/nphys2309; 2012), enabling the authors, who had been concerned about violating the journal’s embargo, to speak about it publicly for the first time. They say that the mathematics leaves no doubt that the wavefunction is not just a statistical tool, but rather, a real, objective state of a quantum system…

The authors have some heavyweights in their corner: their view was once shared by Austrian physicist and quantum-mechanics pioneer Erwin Schrödinger, who proposed in his famous thought experiment that a quantum-mechanical cat could be dead and alive at the same time. But other physicists have favoured an opposing view, one held by Albert Einstein: that the wavefunction reflects the partial knowledge an experimenter has about a system. In this interpretation, the cat is either dead or alive, but the experimenter does not know which. This ‘epistemic’ interpretation, many physicists and philosophers argue, better explains the phenomenon of wavefunction collapse, in which a quantum state is fundamentally changed by measuring it…

Read the full story in Nature.

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As we listen for the tell-tale purr, we might spare a thought for Gerbert d’Aurillac (who became Pope Sylvester II); he died on this date in 1003.  Gerbert/Sylvester was never canonized; indeed, in his day, he dogged with rumors that he was a sorcerer in league with the devil… which appear to have been the work of reactionary forces resisting both Sylvester’s attempts to rid the Church of corruption (especially simony, the sale of sacraments and indulgences) and his attempts to popularize mathematics, astronomy and mechanics for lay audiences.  Inspired by translations of Arabic texts, he built clocks, invented the hydraulic organ, crafted astronomical instruments, and renewed interest in the abacus for use in mathematical calculations (in the process of which, he seems to have introduced Arabic numerals [except zero]).  It’s not a stretch to suggest that Gerbert/Sylvester began Europe’s long march out of the Dark Ages.

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I’m relatively sure that this is reassuring news…

 

image: Paul Wesley Griggs

The quantum world defies the rules of ordinary logic. Particles routinely occupy two or more places at the same time and don’t even have well-defined properties until they are measured. It’s all strange, yet true – quantum theory is the most accurate scientific theory ever tested and its mathematics is perfectly suited to the weirdness of the atomic world. (…)

Human thinking, as many of us know, often fails to respect the principles of classical logic. We make systematic errors when reasoning with probabilities, for example. Physicist Diederik Aerts of the Free University of Brussels, Belgium, has shown that these errors actually make sense within a wider logic based on quantum mathematics. The same logic also seems to fit naturally with how people link concepts together, often on the basis of loose associations and blurred boundaries. That means search algorithms based on quantum logic could uncover meanings in masses of text more efficiently than classical algorithms.

It may sound preposterous to imagine that the mathematics of quantum theory has something to say about the nature of human thinking. This is not to say there is anything quantum going on in the brain, only that “quantum” mathematics really isn’t owned by physics at all, and turns out to be better than classical mathematics in capturing the fuzzy and flexible ways that humans use ideas. “People often follow a different way of thinking than the one dictated by classical logic,” says Aerts. “The mathematics of quantum theory turns out to describe this quite well.” (…)

Why should quantum logic fit human behaviour? Peter Bruza at Queensland University of Technology in Brisbane, Australia, suggests the reason is to do with our finite brain being overwhelmed by the complexity of the environment yet having to take action long before it can calculate its way to the certainty demanded by classical logic. Quantum logic may be more suitable to making decisions that work well enough, even if they’re not logically faultless. “The constraints we face are often the natural enemy of getting completely accurate and justified answers,” says Bruza.

This idea fits with the views of some psychologists, who argue that strict classical logic only plays a small part in the human mind. Cognitive psychologist Peter Gardenfors of Lund University in Sweden, for example, argues that much of our thinking operates on a largely unconscious level, where thought follows a less restrictive logic and forms loose associations between concepts.

Aerts agrees. “It seems that we’re really on to something deep we don’t yet fully understand.” This is not to say that the human brain or consciousness have anything to do with quantum physics, only that the mathematical language of quantum theory happens to match the description of human decision-making.

Perhaps only humans, with our seemingly illogical minds, are uniquely capable of discovering and understanding quantum theory.

Read the article in its fascinating entirety at New Scientist (via Amira Skowmorowska’s Lapidarium Notes).

 

As we feel even more justified in agreeing with Emerson that “a foolish consistency is the hobgoblin of little minds,” we might recall that it was on this date in 1692 that Giles Corey, a prosperous farmer and full member of the church in early colonial America, died under judicial torture during the Salem witch trials.  Corey refused to enter a plea; he was crushed to death by stone weights in an attempt to force him to do so.

Under the law at the time, a person who refused to plead could not be tried. To avoid persons cheating justice, the legal remedy was “peine forte et dure“– a process in which the prisoner is stripped naked and placed prone under a heavy board. Rocks or boulders are then laid on the wood. Corey was the only person in New England to suffer this punishment, though Margaret Clitherow was similarly crushed in England in 1586 for refusing to plead to the charge of secretly practicing Catholicism.

Corey’s last words were “more weight.”

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