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Posts Tagged ‘Physics

“Every why hath a wherefore”*…

 

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Physicists have started to realise that causality might not be as straightforward as we thought. Instead of cause always preceding effect, effects can sometimes precipitate their causes. And, even more mindbogglingly, both can be true at once. In this version of events, you would be opening the fridge because the butter was already on the table, and your toast would be perfectly golden both before and after you put it in the toaster. You wouldn’t just be making breakfast – your breakfast would also be making you.

Playing fast and loose with causality does more than make for confusing mornings. It could shake physics to its very foundations. No longer having a definite order of events goes against the picture of the universe painted by general relativity, and even hints at a reality beyond quantum mechanics, the best model we have of the subatomic world. Allowing causality to operate in both directions could allow us to combine these two theories into a single framework of quantum gravity, a goal that has eluded us for over a century. The end of causality as we know it …

In everyday life, causes always precede effects.  But new experiments suggests that things might be different when things get very, very tiny: “In the quantum realm, cause doesn’t necessarily come before effect.”

* Shakespeare, Comedy of Errors

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As we get small, we might recall that it was on this date in 1564 that results of the Council of Trent (Concilium Tridentinum) were published, condemning what the Catholic Church deemed to be the heresies of Protestants.  The embodiment of the Counter-Reformation, it established a firm and permanent distinction between the two practices of faith.

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Council of Trent (painting in the Museo del Palazzo del Buonconsiglio, Trento)

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Written by LW

January 26, 2020 at 1:01 am

“Reality leaves a lot to the imagination”*…

 

cloud-computing

 

Here’s a curious thought experiment. Imagine a cloud of quantum particles that are entangled—in other words, they share the same quantum existence. The behavior of these particles is chaotic. The goal of this experiment is to send a quantum message across this set of particles. So the message has to be sent into one side of the cloud and then extracted from the other.

The first step, then, is to divide the cloud down the middle so that the particles on the left can be controlled separately from those on the right. The next step is to inject the message into the left-hand part of the cloud, where the chaotic behavior of the particles quickly scrambles it.

Can such a message ever be unscrambled?

Today, we get an answer thanks to the work of Adam Brown at Google in California and a number of colleagues, including Leonard Susskind at Stanford University, the “father of string theory.” This team shows exactly how such a message can be made to surprisingly reappear.

“The surprise is what happens next,” they say. After a period in which the message seems thoroughly scrambled, it abruptly unscrambles and recoheres at a point far away from where it was originally inserted. “The signal has unexpectedly refocused, without it being at all obvious what it was that acted as the lens,” they say.

But their really extraordinary claim is that such an experiment throws light on one of the deepest mysteries of the universe: the quantum nature of gravity and spacetime…

Quantum entanglement, and what it might tell us about quantum gravity– the fascinating story in full: “How a tabletop experiment could test the bedrock of reality.”

[The arXiv paper on which this article reports, “Quantum Gravity in the Lab: Teleportation by Size and Traversable Wormholes,” is here.]

* John Lennon

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As we contemplate connection, we might spare a thought for George Boole; the philosopher and mathematician died on this date in 1864.  Boole helped establish modern symbolic logic– he created symbols to stand for logical operations– and an algebra of logic (that is now called “Boolean algebra”).  Boole made important contributions to the study of differential equations and other aspects of math; his algebra has found important applications in topology, measure theory, probability, and statistics.  But it’s for the foundational contribution that his symbolic logic has made to computer science– from circuit design to programming– that he’s probably best remembered.

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Happy Birthday (1894), James Thurber!!

 

“There is a size at which dignity begins”*…

 

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The spectrometer for the KATRIN experiment, as it works its way through the German town of Eggenstein-Leopoldshafen in 2006 en route to the nearby Karlsruhe Institute of Technology

 

Isaac Asimov dubbed neutrinos “ghost particles.” John Updike immortalized them in verse. They’ve been the subject of several Nobel Prize citations, because these weird tiny particles just keep surprising physicists. And now we have a much better idea of the upper limit of what their rest mass could be, thanks to the first results from the Karlsruhe Tritium Neutrino experiment (KATRIN) in Germany. Leaders from the experiment announced their results last week at a scientific conference in Japan and posted a preprint to the physics arXiv.

“Knowing the mass of the neutrino will allow scientists to answer fundamental questions in cosmology, astrophysics, and particle physics, such as how the universe evolved or what physics exists beyond the Standard Model,” said Hamish Robertson, a KATRIN scientist and professor emeritus of physics at the University of Washington…

Physicists get small: “Weighing in: Physicists cut upper limit on neutrino’s mass in half.”

* Thomas Hardy, “Two on a Tower”

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As we step onto the scales, we might spare a thought for Max Karl Ernst Ludwig Planck; he died on this date in 1947.  A theoretical physicist, he is best remembered as the originator of quantum theory.  It was his discovery of energy quanta that won him the Nobel Prize in Physics in 1918.

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Written by LW

October 4, 2019 at 1:01 am

“Reality is merely an illusion, albeit a very persistent one”*…

 

Science_View-On-G2-Mirror

To look for the strange wave-like properties of quantum particles, physicists hurtle them through a long tunnel-like instrument known as an interferometer

 

Magnify a speck of dirt a thousand times, and suddenly it no longer seems to play by the same rules. Its outline, for example, won’t look well-defined most of the time and will resemble a diffuse, sprawling cloud. That’s the bizarre realm of quantum mechanics. “In some books, you’ll find they say a particle is in various places at once,” says physicist Markus Arndt of the University of Vienna in Austria. “Whether that really happens is a matter of interpretation.”

Another way of putting it: Quantum particles sometimes act like waves, spread out in space. They can slosh into each other and even back onto themselves. But if you poke at this wave-like object with certain instruments, or if the object interacts in specific ways with nearby particles, it loses its wavelike properties and starts acting like a discrete point—a particle. Physicists have observed atoms, electrons, and other minutiae transitioning between wave-like and particle-like states for decades.

But at what size do quantum effects no longer apply? How big can something be and still behave like both a particle and a wave? Physicists have struggled to answer that question because the experiments have been nearly impossible to design.

Now, Arndt and his team have circumvented those challenges and observed quantum wave-like properties in the largest objects to date—molecules composed of 2,000 atoms, the size of some proteins. The size of these molecules beats the previous record by two and a half times. To see this, they injected the molecules into a 5-meter-long tube. When the particles hit a target at the end, they didn’t just land as randomly scattered points. Instead, they formed an interference pattern, a striped pattern of dark and light stripes that suggests waves colliding and combining with each other…

One possibility physicists are exploring is that quantum mechanics might in fact apply at all scales. “You and I, while we sit and talk, do not feel quantum,” says Arndt. We seem to have distinct outlines and do not crash and combine with each other like waves in a pond. “The question is, why does the world look so normal when quantum mechanics is so weird?”…

A record-breaking experiment shows an enormous molecule is also both a particle and a wave—and that quantum effects don’t only apply at tiny scales: “Even Huge Molecules Follow the Quantum World’s Bizarre Rules.”

Read the paper published in Nature Physics by Arndt and his team here.

* Albert Einstein

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As we dwell on duality, we might spare a thought for August Ferdinand Möbius; he died on this date in 1868.  A German mathematician and theoretical astronomer, he is best remembered as a topologist, more specifically for his discovery of the Möbius strip (a two-dimensional surface with only one side… or more precisely, a non-orientable two-dimensional surface with only one side when embedded in three-dimensional Euclidean space).

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Written by LW

September 26, 2019 at 1:01 am

“Matter is energy waiting to happen”*…

 

matter abstractions-a-442

 

Chad Mirkin didn’t set out to discover a new property in matter. But when you’re inventing an alternative to atom-based chemistry, something strange is bound to happen…

While studying materials made from DNA-coated nanoparticles, researchers found a new form of matter– lattices in which smaller particles roam like electrons in metallic bonds: “Strange Metal-like Bonds Discovered in Customized Crystals.”

* Bill Bryson, A Short History of Nearly Everything

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As we muse on matter, we might send irradiated birthday greetings to Irène Joliot-Curie; she was born on this date in 1897.  The daughter of Marie Curie and Pierre Curie and the wife of Frédéric Joliot-Curie, she shared a Nobel Prize with her husband for their joint discovery of artificial radioactivity (making the Curies the family with the most Nobel laureates to date).  Both children of the Joliot-Curies, Hélène and Pierre, are also esteemed scientists.

Like her mother, Irène died of leukemia, likely resulting from radiation exposure during her research.

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Written by LW

September 12, 2019 at 1:01 am

“Toto, I’ve a feeling we’re not in Kansas anymore”*…

 

Matrix

 

in Pensées (1670), Blaise Pascal famously outlined a proposition that has become known as “Pascal’s Wager”:

If there is a God, He is infinitely incomprehensible, since, having, neither parts nor limits, He has no affinity to us. We are then incapable of knowing either what He is or if He is…  [so] belief is a wise wager. Granted that faith cannot be proved, what harm will come to you if you gamble on its truth and it proves false? If you gain, you gain all; if you lose, you lose nothing. Wager, then, without hesitation, that He exists.

In last Sunday’s New York Times, philosophy professor Preston Greene updates– and inverts– Pascal’s logic.  Noting that scientists are proposing an experimental test of Oxford professor Nick Bostrom‘s assertion that we are living in an elaborate simulation, Greene argues strongly against it…

So far, none of these experiments has been conducted, and I hope they never will be. Indeed, I am writing to warn that conducting these experiments could be a catastrophically bad idea — one that could cause the annihilation of our universe.Think of it this way. If a researcher wants to test the efficacy of a new drug, it is vitally important that the patients not know whether they’re receiving the drug or a placebo. If the patients manage to learn who is receiving what, the trial is pointless and has to be canceled.

In much the same way, as I argue in a forthcoming paper in the journal Erkenntnis, if our universe has been created by an advanced civilization for research purposes, then it is reasonable to assume that it is crucial to the researchers that we don’t find out that we’re in a simulation. If we were to prove that we live inside a simulation, this could cause our creators to terminate the simulation — to destroy our world.Of course, the proposed experiments may not detect anything that suggests we live in a computer simulation. In that case, the results will prove nothing. This is my point: The results of the proposed experiments will be interesting only when they are dangerous. While there would be considerable value in learning that we live in a computer simulation, the cost involved — incurring the risk of terminating our universe — would be many times greater…

As far as I am aware, no physicist proposing simulation experiments has considered the potential hazards of this work. This is surprising, not least because Professor Bostrom himself explicitly identified “simulation shutdown” as a possible cause of the extinction of all human life.

This area of academic research is rife with speculation and uncertainty, but one thing is for sure: If scientists do go ahead with these simulation experiments, the results will be either extremely uninteresting or spectacularly dangerous. Is it really worth the risk?

The piece in full: “Are We Living in a Computer Simulation? Let’s Not Find Out.”

[Image above, The Matrix, back in theaters on the occasion of its 20th anniversary]

* The Wizard of Oz

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As we rethink reality, we might send elastic birthday greetings to Peter Hodgson; he was born on this date in 1912.  An advertising and marketing consultant, Hodgson introduced Silly Putty to the world.  As The New York Times recounted in his obituary,

The stuff had been developed by General Electric scientists in the company’s New Haven laboratories several years earlier in a search for a viable synthetic rubber. It was obviously not satisfactory, and it found its way instead onto the local cocktail party circuit.

That’s where Mr. Hodgson, who was at the time writing a catalogue of toys for a local store, saw it, and an idea was born.

“Everybody kept saying there was no earthly use for the stuff” he later recalled. “But I watched them as they fooled with it. I couldn’t help noticing how people with busy schedules wasted as much as 15 minutes at a shot just fondling and stretching it”.

“I decided to take a chance and sell some. We put an ad in the catalogue on the adult page, along with such goodies as a spaghetti-making machine. We packaged the goop in a clear compact case and tagged it at $1.00”.

Having borrowed $147 for the venture, Mr. Hodgson ordered a batch from General Electric, hired a Yale student to separate the gob into one ounce dabs and began filling orders. At the same time he hurried to get some trademarks.

Silly Putty was an instant success, and Mr. Hodgson quickly geared up to take advantage of it…

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Written by LW

August 15, 2019 at 1:01 am

“Why should things be easy to understand?”*…

 

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The universe is kind of an impossible object. It has an inside but no outside; it’s a one-sided coin. This Möbius architecture presents a unique challenge for cosmologists, who find themselves in the awkward position of being stuck inside the very system they’re trying to comprehend.

It’s a situation that Lee Smolin has been thinking about for most of his career. A physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, Smolin works at the knotty intersection of quantum mechanics, relativity and cosmology. Don’t let his soft voice and quiet demeanor fool you — he’s known as a rebellious thinker and has always followed his own path. In the 1960s Smolin dropped out of high school, played in a rock band called Ideoplastos, and published an underground newspaper. Wanting to build geodesic domes like R. Buckminster Fuller, Smolin taught himself advanced mathematics — the same kind of math, it turned out, that you need to play with Einstein’s equations of general relativity. The moment he realized this was the moment he became a physicist. He studied at Harvard University and took a position at the Institute for Advanced Study in Princeton, New Jersey, eventually becoming a founding faculty member at the Perimeter Institute.

“Perimeter,” in fact, is the perfect word to describe Smolin’s place near the boundary of mainstream physics. When most physicists dived headfirst into string theory, Smolin played a key role in working out the competing theory of loop quantum gravity. When most physicists said that the laws of physics are immutable, he said they evolve according to a kind of cosmic Darwinism. When most physicists said that time is an illusion, Smolin insisted that it’s real.

Smolin often finds himself inspired by conversations with biologists, economists, sculptors, playwrights, musicians and political theorists. But he finds his biggest inspiration, perhaps, in philosophy — particularly in the work of the German philosopher Gottfried Leibniz, active in the 17th and 18th centuries, who along with Isaac Newton invented calculus. Leibniz argued (against Newton) that there’s no fixed backdrop to the universe, no “stuff” of space; space is just a handy way of describing relationships. This relational framework captured Smolin’s imagination, as did Leibniz’s enigmatic text The Monadology, in which Leibniz suggests that the world’s fundamental ingredient is the “monad,” a kind of atom of reality, with each monad representing a unique view of the whole universe. It’s a concept that informs Smolin’s latest work as he attempts to build reality out of viewpoints, each one a partial perspective on a dynamically evolving universe. A universe as seen from the inside…

Lee Smolin explains his radical idea for how to understand an object with no exterior–imagine it built bit-by-bit from relationships between events: “How to Understand the Universe When You’re Stuck Inside of It.”

* Thomas Pynchon

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As we muse on monads, we might send delightful birthday greetings to Fernando Arrabal Terán; he was born on this date in 1932.  A playwright, screenwriter, film director, novelist, and poet, Arrabal co-founded the Panic Movement with Alejandro Jodorowsky and Roland Topor (inspired by the god Pan).

Early in his career, he spent three years as a member of André Breton’s surrealist group and was a friend of Andy Warhol and Tristan Tzara.  Later (in 1990), he was elected Transcendent Satrap of the Collège de  ‘pataphysique (following such predecessors as Marcel Duchamp, Eugène Ionesco, Man Ray, Boris Vian, Dario Fo, Umberto Eco, and Jean Baudrillard).

And throughout, he was very productive: Arrabal has directed seven full-length feature films and has published over 100 plays; 14 novels; 800 poetry collections, chapbooks, and artists’ books; several essays; and his notorious “Letter to General Franco” during the dictator’s lifetime.  His complete plays have been published, in multiple languages, in a two-volume edition totaling over two thousand pages. The New York Times theater critic Mel Gussow has called Arrabal the last survivor among the “three avatars of modernism.”

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Written by LW

August 11, 2019 at 1:01 am

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