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Posts Tagged ‘quantum theory

“The threat of a pandemic is different from that of a nerve agent, in that a disease can spread uncontrollably, long after the first carrier has succumbed”*…

We were, of course, warned. As we do our best to digest the news of emergent new strains of the COVID-19 virus, a look back at Annie Sparrow‘s 2016 New York Review of Books essay on pandemics…

Pandemics—the uncontrolled spread of highly contagious diseases across countries and continents—are a modern phenomenon. The word itself, a neologism from Greek words for “all” and “people,” has been used only since the mid-nineteenth century. Epidemics—localized outbreaks of diseases—have always been part of human history, but pandemics require a minimum density of population and an effective means of transport. Since “Spanish” flu burst from the trenches of World War I in 1918, infecting 20 percent of the world’s population and killing upward of 50 million people, fears of a similar pandemic have preoccupied public health practitioners, politicians, and philanthropists. World War II, in which the German army deliberately caused malaria epidemics and the Japanese experimented with anthrax and plague as biological weapons, created new fears…

According to the doctor, writer, and philanthropist Larry Brilliant, “outbreaks are inevitable, pandemics are optional.”

Much of human history can be seen as a struggle for survival between humans and microbes. Pandemics are microbe offensives; public health measures are human defenses. Water purification, sanitation, and vaccination are crucial to our living longer, better, even taller lives. But these measures of mass salvation are not sexy. While we know prevention is better and considerably cheaper than cure, there is little financial reward or glory in it. Philanthropists prefer to build hospitals rather than pay community health workers. Pharmaceutical companies prefer the Western market to the distant and poor Global South where people cannot afford to buy treatments. Education is a powerful social vaccine against the ignorance that enables pathogens to flourish, but insufficient to overcome the corruption of public goods by private interests. The current enthusiasm for detecting the next panic-inducing pathogen should not divert resources and research from the perennial threats that we already have. We must resist the tendency of familiarity and past failures to encourage contempt and indifference…

An important (and in its time, sadly, prescient) read: “The Awful Diseases on the Way,” from @annie_sparrow in @nybooks.

See also “6 of the Worst Pandemics in History” (source of the image above) and “A history of pandemics.”

[TotH to MK]

Hannah Fry

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As we prioritize preparation, we might recall that it was on this date in 1935 that physicist Erwin Schrödinger published his famous thought experiment– now known as “Schrödinger’s cat“– a paradox that illustrates the problem of the Copenhagen interpretation of quantum mechanics.

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“Men knew better than they realized, when they placed the abode of the gods beyond the reach of gravity”*…

In search of a theory of everything…

Twenty-five particles and four forces. That description — the Standard Model of particle physics — constitutes physicists’ best current explanation for everything. It’s neat and it’s simple, but no one is entirely happy with it. What irritates physicists most is that one of the forces — gravity — sticks out like a sore thumb on a four-fingered hand. Gravity is different.

Unlike the electromagnetic force and the strong and weak nuclear forces, gravity is not a quantum theory. This isn’t only aesthetically unpleasing, it’s also a mathematical headache. We know that particles have both quantum properties and gravitational fields, so the gravitational field should have quantum properties like the particles that cause it. But a theory of quantum gravity has been hard to come by.

In the 1960s, Richard Feynman and Bryce DeWitt set out to quantize gravity using the same techniques that had successfully transformed electromagnetism into the quantum theory called quantum electrodynamics. Unfortunately, when applied to gravity, the known techniques resulted in a theory that, when extrapolated to high energies, was plagued by an infinite number of infinities. This quantization of gravity was thought incurably sick, an approximation useful only when gravity is weak.

Since then, physicists have made several other attempts at quantizing gravity in the hope of finding a theory that would also work when gravity is strong. String theory, loop quantum gravity, causal dynamical triangulation and a few others have been aimed toward that goal. So far, none of these theories has experimental evidence speaking for it. Each has mathematical pros and cons, and no convergence seems in sight. But while these approaches were competing for attention, an old rival has caught up.

The theory called asymptotically (as-em-TOT-ick-lee) safe gravity was proposed in 1978 by Steven Weinberg. Weinberg, who would only a year later share the Nobel Prize with Sheldon Lee Glashow and Abdus Salam for unifying the electromagnetic and weak nuclear force, realized that the troubles with the naive quantization of gravity are not a death knell for the theory. Even though it looks like the theory breaks down when extrapolated to high energies, this breakdown might never come to pass. But to be able to tell just what happens, researchers had to wait for new mathematical methods that have only recently become available…

For decades, physicists have struggled to create a quantum theory of gravity. Now an approach that dates to the 1970s is attracting newfound attention: “Why an Old Theory of Everything Is Gaining New Life,” from @QuantaMagazine.

* Arthur C. Clarke, 2010: Odyssey Two

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As we unify, we might pause to remember Sir Arthur Stanley Eddington, OM, FRS; he died in this date in 1944.  An astrophysicist, mathematician, and philosopher of science known for his work on the motion, distribution, evolution and structure of stars, Eddington is probably best remembered for his relationship to Einstein:  he was, via a series of widely-published articles, the primary “explainer” of Einstein’s Theory of General Relativity to the English-speaking world; and he was, in 1919, the leader of the experimental team that used observations of a solar eclipse to confirm the theory.

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“The past, like the future, is indefinite and exists only as a spectrum of possibilities”*…

A recent paper by Robert Lanza and others suggests that physical reality isn’t independent of us, “objective,” but is the product of networks of observers…

Is there physical reality that is independent of us? Does objective reality exist at all? Or is the structure of everything, including time and space, created by the perceptions of those observing it? Such is the groundbreaking assertion of a new paper published in the Journal of Cosmology and Astroparticle Physics.

The paper’s authors include Robert Lanza, a stem cell and regenerative medicine expert, famous for the theory of biocentrism, which argues that consciousness is the driving force for the existence of the universe. He believes that the physical world that we perceive is not something that’s separate from us but rather created by our minds as we observe it. According to his biocentric view, space and time are a byproduct of the “whirl of information” in our head that is weaved together by our mind into a coherent experience.

His new paper, co-authored by Dmitriy Podolskiy and Andrei Barvinsky, theorists in quantum gravity and quantum cosmology, shows how observers influence the structure of our reality.

According to Lanza and his colleagues, observers can dramatically affect “the behavior of observable quantities” both at microscopic and massive spatiotemporal scales. In fact, a “profound shift in our ordinary everyday worldview” is necessary, wrote Lanza in an interview with Big Think. The world is not something that is formed outside of us, simply existing on its own. “Observers ultimately define the structure of physical reality itself,” he stated.

How does this work? Lanza contends that a network of observers is necessary and is “inherent to the structure of reality.” As he explains, observers — you, me, and anyone else — live in a quantum gravitational universe and come up with “a globally agreed-upon cognitive model” of reality by exchanging information about the properties of spacetime. “For, once you measure something,” Lanza writes, “the wave of probability to measure the same value of the already probed physical quantity becomes ‘localized’ or simply ‘collapses.’” That’s how reality comes to be consistently real to us all. Once you keep measuring a quantity over and over, knowing the result of the first measurement, you will see the outcome to be the same.

“Similarly, if you learn from somebody about the outcomes of their measurements of a physical quantity, your measurements and those of other observers influence each other ‒ freezing the reality according to that consensus,” added Lanza, explaining further that “a consensus of different opinions regarding the structure of reality defines its very form, shaping the underlying quantum foam,” explained Lanza.

In quantum terms, an observer influences reality through decoherence, which provides the framework for collapsing waves of probability, “largely localized in the vicinity of the cognitive model which the observer builds in their mind throughout their lifespan,” he added.

Lanza says, “The observer is the first cause, the vital force that collapses not only the present, but the cascade of spatiotemporal events we call the past. Stephen Hawking was right when he said: ‘The past, like the future, is indefinite and exists only as a spectrum of possibilities.’”

Could an artificially intelligent entity without consciousness be dreaming up our world? Lanza believes biology plays an important role, as he explains in his book The Grand Biocentric Design: How Life Creates Reality, which he co-authored with the physicist Matej Pavsic.

While a bot could conceivably be an observer, Lanza thinks a conscious living entity with the capacity for memory is necessary to establish the arrow of time. “‘A brainless’ observer does not experience time and/or decoherence with any degree of freedom,” writes Lanza. This leads to the cause and effect relationships we can notice around us. Lanza thinks that “we can only say for sure that a conscious observer does indeed collapse a quantum wave function.”…

Another key aspect of their work is that it resolves “the exasperating incompatibility between quantum mechanics and general relativity,” which was a sticking point even for Albert Einstein.

The seeming incongruity of these two explanations of our physical world — with quantum mechanics looking at the molecular and subatomic levels and general relativity at the interactions between massive cosmic structures like galaxies and black holes — disappears once the properties of observers are taken into account.

While this all may sound speculative, Lanza says their ideas are being tested using Monte Carlo simulations on powerful MIT computer clusters and will soon be tested experimentally.

Is the physical universe independent from us, or is it created by our minds? “Is human consciousness creating reality?@RobertLanza

We might wonder, if this is so, how reality emerged at all. Perhaps one possibility is implied in “Consciousness was upon him before he could get out of the way.”

* Stephen Hawking

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As we conjure with consciousness, we might recall that it was on this date in 1908 (the same year that he was awarded the Nobel Prize in Physics) that Ernest Rutherford announced in London that he had isolated a single atom of matter. The following year, he, Hans Geiger (later of “counter” fame), and Ernest Marsden conducted the “Gold Foil Experiment,” the results of which replaced J. J. Thomson‘s “Plum Pudding Model” of the atom with what became known as the “Rutherford Model“: a very small charged nucleus, containing much of the atom’s mass, orbited by low-mass electrons.

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“Bohr was inconsistent, unclear, willfully obscure, and right. Einstein was consistent, clear, down-to-earth, and wrong.”*…

The founders of quantum mechanics understood it to be deeply, profoundly weird. Albert Einstein, for one, went to his grave convinced that the theory had to be just a steppingstone to a more complete description of nature, one that would do away with the disturbing quirks of the quantum.

Then in 1964, John Stewart Bell proved a theorem that would test whether quantum theory was obscuring a full description of reality, as Einstein claimed. Experimenters have since used Bell’s theorem to rule out the possibility that beneath all the apparent quantum craziness — the randomness and the spooky action at a distance — is a hidden deterministic reality that obeys the laws of relativity.

Now a new theorem has taken Bell’s work a step further. The theorem makes some reasonable-sounding assumptions about physical reality. It then shows that if a certain experiment were carried out — one that is, to be fair, extravagantly complicated — the expected results according to the rules of quantum theory would force us to reject one of those assumptions.

According to Matthew Leifer, a quantum physicist at Chapman University who did not participate in the research, the new work focuses attention on a class of interpretations of quantum mechanics that until now have managed to escape serious scrutiny from similar “no-go” theorems.

Broadly speaking, these interpretations argue that quantum states reflect our own knowledge of physical reality, rather than being faithful representations of something that exists out in the world. The exemplar of this group of ideas is the Copenhagen interpretation, the textbook version of quantum theory, which is most popularly understood to suggest that particles don’t have definite properties until those properties are measured. Other Copenhagen-like quantum interpretations go even further, characterizing quantum states as subjective to each observer…

… which has, as you will see as you read on in the piece excerpted above, some pretty profoundly weird implications. Either the rules of quantum mechanics don’t always apply, or at least one basic assumption about reality must be wrong: “A New Theorem Maps Out the Limits of Quantum Physics.”

See also “Reality is that which, when you stop believing in it, doesn’t go away.”

* John Stewart Bell

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As we pity Schrödinger’s cat, we might we might send penetrating birthday greetings to Henry Way Kendall; he was born on this date in 1926. A particle physicist, he shared the Nobel Prize in Physics in 1990 (with Jerome Isaac Friedman and Richard E. Taylor) “for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics.”

In 1969, Kendall helped found the Union of Concerned Scientists. In 1997, in connection with the Kyoto Climate Summit, he helped produce a statement signed by 2,000 scientists calling for action on global warming.

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“You’re mad, bonkers, completely off your head. But I’ll tell you a secret. All the best people are.”*…

Edward Brooke-Hitching grew up in a rare book shop, with a rare book dealer for a father. As the author of histories of maps The Phantom Atlas, The Golden Atlas and The Sky Atlas, he has always been “really fascinated by books that are down the back alleys of history.” Ten years ago, he embarked on a project to come up with the “ultimate library.” No first editions of Jane Austen here, though: Brooke-Hitching’s The Madman’s Library collects the most eccentric and extraordinary books from around the world.

“I was asking, if you could put together the ultimate library, ignoring the value or the academic significance of the books, what would be on that shelf if you had a time machine and unlimited budget?” he says.

Following up anecdotes, talking to booksellers and librarians and trawling through auction catalogues, he came across stories like that of the 605-page Qur’an written in the blood of Saddam Hussein. “If that was on a shelf, what could possibly sit next to it?” he asks. “I mentioned it to a bookseller and they told me about a diary that they’d had, from the 19th century, written by a shipwrecked captain who only had old newspaper and penguins to hand. So Fate of the Blenden Hall was written entirely in penguin blood.”

There’s the American civil war soldier who inscribed his journal of the conflict on to the violin he carried. There’s the memoir of a Massachussetts highwayman, James Allen, which he “requested be bound in his own skin after his death, and presented to his one victim who had fought back as a token of his admiration.” Or the diary of the Norwegian resistance fighter Petter Moen, pricked with a pin into squares of toilet paper and left in a ventilation shaft; although Moen was killed in 1944, one of his fellow prisoners returned to Oslo after it was liberated from the Nazis and found the diary. Or the entirely fabricated book An Historical and Geographical Description of Formosa: its author George Psalmanazar, a blond-haired, blue-eyed, pale-skinned man with a thick French accent, arrived in London in about 1702 and declared himself to be the first Formosan, or Taiwanese, person to set foot on the European continent. (“Obviously no one had been there and nobody knew what Taiwanese people looked like, and he became the toast of high society,” says Brooke-Hitching.)

The joy for the author in his discoveries – and make no mistake, The Madman’s Library is an utterly joyous journey into the deepest eccentricities of the human mind – was that they “make you realise that, above everything, people have always been funny, been weird, been unquenchably curious in every possible arena”…

The Madman’s Library, the ultimate collection of bizarre books down the ages: “From cut-out confessions to cheese pages: browse the world’s strangest books.”

[TotH to buddy MK]

* Lewis Carroll, Alice’s Adventures in Wonderland

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As we get weird, we might recall that it was on this date in 1935 that physicist Erwin Schrödinger published his famous thought experiment– now known as “Schrödinger’s cat“– a paradox that illustrates the problem of the Copenhagen interpretation of quantum mechanics.

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