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Posts Tagged ‘Cosmology

“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

“Oh how wrong we were to think immortality meant never dying”*…

 

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Quantum simulation (Verresen et al., Nature Physics, 2019)

 

Further (in a fashion) to yesterday’s post…

Nothing lasts forever. Humans, planets, stars, galaxies, maybe even the Universe itself, everything has an expiration date. But things in the quantum realm don’t always follow the rules. Scientists have found that quasiparticles in quantum systems could be effectively immortal.

That doesn’t mean they don’t decay, which is reassuring. But once these quasiparticles have decayed, they are able to reorganise themselves back into existence, possibly ad infinitum.

This seemingly flies right in the face of the second law of thermodynamics, which asserts that entropy in an isolated system can only move in an increasing direction: things can only break down, not build back up again.

Of course, quantum physics can get weird with the rules; but even quantum scientists didn’t know quasiparticles were weird in this particular manner…

Maybe some things are forever.  More at “Scientists Find Evidence a Strange Group of Quantum Particles Are Basically Immortal.”

Read the underlying Nature Physics article, by physicist Ruben Verresen and his team at the Technical University of Munich and the Max Planck Institute for the Physics of Complex Systems, here.

* Gerard Way

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As we ponder perpetuity, we might send carefully-deduced birthday greetings to Richard Bevan Braithwaite; he was born on this date in 1900.  A Cambridge don who specialized in the philosophy of science, he focused on the logical features common to all sciences.  Braithwaite was concerned with the impact of science on our beliefs about the world and the appropriate responses to that impact.  He was especially interested in probability (and its applications in decision theory and games theory) and in the statistical sciences.  He was president of the Aristotelian Society from 1946 to 1947, and was a Fellow of the British Academy.

It was Braithwaite’s poker that Ludwig Wittgenstein reportedly brandished at Karl Popper during their confrontation at a Moral Sciences Club meeting in Braithwaite’s rooms in King’s College. The implement subsequently disappeared. (See here.)

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“Nothing happens until something moves”*…

 

Universe

 

What determines our fate? To the Stoic Greek philosophers, fate is the external product of divine will, ‘the thread of your destiny’. To transcendentalists such as Henry David Thoreau, it is an inward matter of self-determination, of ‘what a man thinks of himself’. To modern cosmologists, fate is something else entirely: a sweeping, impersonal physical process that can be boiled down into a single, momentous number known as the Hubble Constant.

The Hubble Constant can be defined simply as the rate at which the Universe is expanding, a measure of how quickly the space between galaxies is stretching apart. The slightest interpretation exposes a web of complexity encased within that seeming simplicity, however. Extrapolating the expansion process backward implies that all the galaxies we can observe originated together at some point in the past – emerging from a Big Bang – and that the Universe has a finite age. Extrapolating forward presents two starkly opposed futures, either an endless era of expansion and dissipation or an eventual turnabout that will wipe out the current order and begin the process anew.

That’s a lot of emotional and intellectual weight resting on one small number…

How scientists pinned a single number on all of existence: “Fate of the Universe.”

[Readers might remember that the Big Bang wasn’t always an accepted paradigm— and that on-going research continues to surface challenges.]

* Albert Einstein

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As we center ourselves, we might spare a thought for Kurt Friedrich Gödel; he died on this date in 1978.  A  logician, mathematician, and philosopher, he is considered (along with Aristotle, Alfred Tarski— whose birthday this also is– and Gottlob Frege) to be one of the most important logicians in history.  Gödel had an immense impact upon scientific and philosophical thinking in the 20th century.  He is, perhaps, best remembered for his Incompleteness Theorems, which led to (among other important results) Alan Turing’s insights into computational theory.

Kurt Gödel’s achievement in modern logic is singular and monumental – indeed it is more than a monument, it is a landmark which will remain visible far in space and time. … The subject of logic has certainly completely changed its nature and possibilities with Gödel’s achievement.                  — John von Neumann

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“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

“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?”*…

 

Lee-Smolin_2K_02

 

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

“I think I can safely say that nobody understands quantum mechanics”*…

 

Quantum_Darwinism_2880x1620_Lede

 

But we may be getting a little bit closer…

It’s not surprising that quantum physics has a reputation for being weird and counterintuitive. The world we’re living in sure doesn’t feel quantum mechanical. And until the 20th century, everyone assumed that the classical laws of physics devised by Isaac Newton and others — according to which objects have well-defined positions and properties at all times — would work at every scale. But Max Planck, Albert Einstein, Niels Bohr and their contemporaries discovered that down among atoms and subatomic particles, this concreteness dissolves into a soup of possibilities. An atom typically can’t be assigned a definite position, for example — we can merely calculate the probability of finding it in various places. The vexing question then becomes: How do quantum probabilities coalesce into the sharp focus of the classical world?

Physicists sometimes talk about this changeover as the “quantum-classical transition.” But in fact there’s no reason to think that the large and the small have fundamentally different rules, or that there’s a sudden switch between them. Over the past several decades, researchers have achieved a greater understanding of how quantum mechanics inevitably becomes classical mechanics through an interaction between a particle or other microscopic system and its surrounding environment.

One of the most remarkable ideas in this theoretical framework is that the definite properties of objects that we associate with classical physics — position and speed, say — are selected from a menu of quantum possibilities in a process loosely analogous to natural selection in evolution: The properties that survive are in some sense the “fittest.” As in natural selection, the survivors are those that make the most copies of themselves. This means that many independent observers can make measurements of a quantum system and agree on the outcome — a hallmark of classical behavior.

This idea, called quantum Darwinism (QD), explains a lot about why we experience the world the way we do rather than in the peculiar way it manifests at the scale of atoms and fundamental particles. Although aspects of the puzzle remain unresolved, QD helps heal the apparent rift between quantum and classical physics.

Only recently, however, has quantum Darwinism been put to the experimental test…

How do quantum possibilities give rise to objective, classical reality?  More on one possible explanation, quantum Darwinism– and on the three experiments that have have begun to vet the theory: “Quantum Darwinism, an Idea to Explain Objective Reality, Passes First Tests.”

* Richard Feynman

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As we ruminate on reality, we might recall that it was on this date in 1975 that Jimmy Hoffa disappeared from the parking lot of the Machus Red Fox restaurant in Bloomfield Hills, Michigan, a suburb of Detroit, at about 2:30 p.m.  He was never seen or heard from again.

Hoffa had served as President of the International Brotherhood of Teamsters from 1957.  Long suspected of mob ties, he was convicted of jury tampering, attempted bribery and fraud in 1964, and sentenced to 13 years in prison in 1967… from whence he continued in his union office until 1972, when he was pardoned by President Richard Nixon on the condition that he resign Teamsters office.  Out of jail, he began to plot an attempt to reverse this condition and return to power.  Before he could make much progress, he disappeared.  He was declared legally dead in 1982.  While there has never been an official explanation of Hoffa’s demise, it is widely believed that he was killed by the Mafia, which was uncomfortable with his efforts to disrupt the power structure of the Teamsters (over which they has reestablished control).

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Written by LW

July 30, 2019 at 1:01 am

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