(Roughly) Daily

Posts Tagged ‘Physics

“I have not yet lost a feeling of wonder, and of delight, that the delicate motion should reside in all the things around us”*…

The proton, the positively charged particle at the heart of the atom, is an object of unspeakable complexity, one that changes its appearance depending on how it is probed…

“This is the most complicated thing that you could possibly imagine,” said Mike Williams, a physicist at the Massachusetts Institute of Technology. “In fact, you can’t even imagine how complicated it is.”

The proton is a quantum mechanical object that exists as a haze of probabilities until an experiment forces it to take a concrete form. And its forms differ drastically depending on how researchers set up their experiment. Connecting the particle’s many faces has been the work of generations. “We’re kind of just starting to understand this system in a complete way,” said Richard Milner, a nuclear physicist at MIT.

As the pursuit continues, the proton’s secrets keep tumbling out. Most recently, a monumental data analysis published in August found that the proton contains traces of particles called charm quarks that are heavier than the proton itself.

The proton “has been humbling to humans,” Williams said. “Every time you think you kind of have a handle on it, it throws you some curveballs.”

Recently, Milner, together with Rolf Ent at Jefferson Lab, MIT filmmakers Chris Boebel and Joe McMaster, and animator James LaPlante, set out to transform a set of arcane plots that compile the results of hundreds of experiments into a series of animations of the shape-shifting proton…

Charlie Wood (and Merrill Sherman) have incorporated that work into an attempt to unveil the particle’s secrets: “Inside the Proton, the ‘Most Complicated Thing You Could Possibly Imagine’,” from @walkingthedot in @QuantaMagazine.

* Edmund Burke

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As we ponder presumptive paradoxes, we might send insightful birthday greetings to David Schramm; he was born on this date in 1945. A theoretical astrophysicist, he established the field of particle astrophysics, a branch of particle physics that studies elementary particles of astronomical origin and their relation to astrophysics and cosmology. He was particularly well known for the study of Big Bang nucleosynthesis and its use as a probe of dark matter and of neutrinos. And he made important contributions to the study of cosmic rays, supernova explosions, heavy-element nucleosynthesis, and nuclear astrophysics generally.

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October 25, 2022 at 1:00 am

“The ‘paradox’ is only a conflict between reality and your feeling of what reality ‘ought to be’”*…

John Stewart Bell (1928-1990), the Northern Irish physicist whose work sparked a quiet revolution in quantum physics

Elegant experiments with entangled light have laid bare a profound mystery at the heart of reality. Daniel Garisto explains the importance of the work done by this year’s Nobel laureates in Physics…

One of the more unsettling discoveries in the past half century is that the universe is not locally real. “Real,” meaning that objects have definite properties independent of observation—an apple can be red even when no one is looking; “local” means objects can only be influenced by their surroundings, and that any influence cannot travel faster than light. Investigations at the frontiers of quantum physics have found that these things cannot both be true. Instead, the evidence shows objects are not influenced solely by their surroundings and they may also lack definite properties prior to measurement. As Albert Einstein famously bemoaned to a friend, “Do you really believe the moon is not there when you are not looking at it?”

This is, of course, deeply contrary to our everyday experiences. To paraphrase Douglas Adams, the demise of local realism has made a lot of people very angry and been widely regarded as a bad move.

Blame for this achievement has now been laid squarely on the shoulders of three physicists: John Clauser, Alain Aspect and Anton Zeilinger. They equally split the 2022 Nobel Prize in Physics “for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.” (“Bell inequalities” refers to the pioneering work of the Northern Irish physicist John Stewart Bell, who laid the foundations for this year’s Physics Nobel in the early 1960s.) Colleagues agreed that the trio had it coming, deserving this reckoning for overthrowing reality as we know it. “It is fantastic news. It was long overdue,” says Sandu Popescu, a quantum physicist at the University of Bristol. “Without any doubt, the prize is well-deserved.”

“The experiments beginning with the earliest one of Clauser and continuing along, show that this stuff isn’t just philosophical, it’s real—and like other real things, potentially useful,” says Charles Bennett, an eminent quantum researcher at IBM…

Quantum foundations’ journey from fringe to favor was a long one. From about 1940 until as late as 1990, the topic was often treated as philosophy at best and crackpottery at worst. Many scientific journals refused to publish papers in quantum foundations, and academic positions indulging such investigations were nearly impossible to come by…

Today, quantum information science is among the most vibrant and impactful subfields in all of physics. It links Einstein’s general theory of relativity with quantum mechanics via the still-mysterious behavior of black holes. It dictates the design and function of quantum sensors, which are increasingly being used to study everything from earthquakes to dark matter. And it clarifies the often-confusing nature of quantum entanglement, a phenomenon that is pivotal to modern materials science and that lies at the heart of quantum computing…

Eminently worth reading in full: “The Universe Is Not Locally Real, and the Physics Nobel Prize Winners Proved It,” from @dangaristo in @sciam.

Apposite: entangled particles and wormholes could be manifestations of the same phenomenon, and resolve paradoxes like information escaping a black hole: “Black Holes May Hide a Mind-Bending Secret About Our Universe.” 

Richard Feynman

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As we rethink reality, we might spare a thought for Walter Brattain; he died on this date in 1987. A physicist (at Bell Labs at the time), he worked with John Bardeen and William Shockley to invent the point-contact transistor in 1947, the birth of the semiconductor– work for which the trio shared the Nobel Prize in Physics in 1956.

At college, Brattain said, he majored in physics and math because they were the only subjects he was good at. He became a solid physicist with a good understanding of theory, but his strength was in physically constructing experiments. Working with the ideas of Shockley and Bardeen, Brattain’s hands built the first transistor. Shortly, the transistor replaced the bulkier vacuum tube for many uses and was the forerunner of microminiature electronic parts.

As semiconductor technology has advanced, it has begun to incorporate quantum effects.

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“Iteration, like friction, is likely to generate heat instead of progress”*…

A word of caution from the wondrous Randall Munroe (@xkcd): “Rotatation.”

* George Eliot, The Mill on the Floss

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As we resist repetition, we might send perpetual birthday greetings to Jean Bernard Léon Foucault; he was born on this date in 1819.  A physicist who made an early measurement of the speed of light, discovered eddy currents, and is credited with naming the gyroscope (although he did not invent it), Foucault is best remembered for the (eponymously-named) Foucault’s Pendulum– suspended from the roof of the Panthéon in Paris– demonstrating the effects of the Earth’s rotation.  Using a long pendulum with a heavy bob, he showed its plane was not static, but rotated at a rate related to Earth’s angular velocity and the latitude of the site.

In fact, essentially the same experimental approach had been used by Vincenzo Viviani as early as 1661; but it was Foucault’s work that caught the public imagination: within years of his 1851 experiment, the were “Foucault’s Pendulums” hanging– and attracting crowds–in major cities across Europe and America.

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September 18, 2022 at 1:00 am

“It is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime”*…

… and it continues to change…

Our universe could be the mirror image of an antimatter universe extending backwards in time before the Big Bang. So claim physicists in Canada, who have devised a new cosmological model positing the existence of an “antiuniverse” which, paired to our own, preserves a fundamental rule of physics called CPT symmetry. The researchers still need to work out many details of their theory, but they say it naturally explains the existence of dark matter.

Standard cosmological models tell us that the universe – space, time and mass/energy – exploded into existence some 14 billion years ago and has since expanded and cooled, leading to the progressive formation of subatomic particles, atoms, stars and planets.

However, Neil Turok of the Perimeter Institute for Theoretical Physics in Ontario reckons that these models’ reliance on ad-hoc parameters means they increasingly resemble Ptolemy’s description of the solar system. One such parameter, he says, is the brief period of rapid expansion known as inflation that can account for the universe’s large-scale uniformity. “There is this frame of mind that you explain a new phenomenon by inventing a new particle or field,” he says. “I think that may turn out to be misguided.”

nstead, Turok and his Perimeter Institute colleague Latham Boyle set out to develop a model of the universe that can explain all observable phenomena based only on the known particles and fields. They asked themselves whether there is a natural way to extend the universe beyond the Big Bang – a singularity where general relativity breaks down – and then out the other side. “We found that there was,” he says.

The answer was to assume that the universe as a whole obeys CPT symmetry. This fundamental principle requires that any physical process remains the same if time is reversed, space inverted and particles replaced by antiparticles. Turok says that this is not the case for the universe that we see around us, where time runs forward as space expands, and there’s more matter than antimatter.

Instead, says Turok, the entity that respects the symmetry is a universe–antiuniverse pair. The antiuniverse would stretch back in time from the Big Bang, getting bigger as it does so, and would be dominated by antimatter as well as having its spatial properties inverted compared to those in our universe [as per the illustration above]…

More at “Our universe has antimatter partner on the other side of the Big Bang, say physicists,” in @PhysicsWorld.

Apposite: “The Big Bang no longer means what it used to.”

* Lawrence M. Krauss, A Universe from Nothing: Why There Is Something Rather Than Nothing

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As we debate doppelgangers, we might send chronologically-accurate birthday greetings to Louis Essen; he was born on this date in 1908. A physicist, he is best remembered for his measurements of time– he invented the quartz crystal ring clock and the first practical atomic clock. His cesium-beam atomic clock ultimately changed the way time is measured: the cesium atom’s natural frequency was formally recognized as the new international unit of time in 1967; the second was defined as exactly 9,192,631,770 oscillations or cycles of the cesium atom’s resonant frequency, replacing the old “second” which had been defined in terms of the Earth’s motion.

Perhaps unsurprisingly, given Essen’s punctilious dedication to accuracy, he was a critic of Einstein’s theory of relativity, particularly as it related to time dilation. Moreover, we note (with an eye to the item above) that Essen’s clocks measured time in only one direction…

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September 6, 2022 at 1:00 am

“Horror vacui”*…

A 1672 book about the vacuum by the German scientist Otto von Guericke depicts a demonstration he gave for Emperor Ferdinand III, in which teams of horses tried unsuccessfully to pull apart the halves of a vacuum-filled copper sphere.

Recently, (Roughly) Daily took a look at nothing– and the perplexing philosophical questions that it raises. Today, Charlie Wood examines nothing’s physical manifestation, the vacuum, and the similarly perplexing questions it raises for physicists…

Millennia ago, Aristotle asserted that nature abhors a vacuum, reasoning that objects would fly through truly empty space at impossible speeds. In 1277, the French bishop Etienne Tempier shot back, declaring that God could do anything, even create a vacuum.

Then a mere scientist pulled it off. Otto von Guericke invented a pump to suck the air from within a hollow copper sphere, establishing perhaps the first high-quality vacuum on Earth. In a theatrical demonstration in 1654, he showed that not even two teams of horses straining to rip apart the watermelon-size ball could overcome the suction of nothing. [See illustration above.]

Since then, the vacuum has become a bedrock concept in physics, the foundation of any theory of something. Von Guericke’s vacuum was an absence of air. The electromagnetic vacuum is the absence of a medium that can slow down light. And a gravitational vacuum lacks any matter or energy capable of bending space. In each case the specific variety of nothing depends on what sort of something physicists intend to describe. “Sometimes, it’s the way we define a theory,” said Patrick Draper, a theoretical physicist at the University of Illinois.

As modern physicists have grappled with more sophisticated candidates for the ultimate theory of nature, they have encountered a growing multitude of types of nothing. Each has its own behavior, as if it’s a different phase of a substance. Increasingly, it seems that the key to understanding the origin and fate of the universe may be a careful accounting of these proliferating varieties of absence.

“We’re learning there’s a lot more to learn about nothing than we thought,” said Isabel Garcia Garcia, a particle physicist at the Kavli Institute for Theoretical Physics in California. “How much more are we missing?”

So far, such studies have led to a dramatic conclusion: Our universe may sit on a platform of shoddy construction, a “metastable” vacuum that is doomed — in the distant future — to transform into another sort of nothing, destroying everything in the process.

Nothing started to seem like something in the 20th century, as physicists came to view reality as a collection of fields: objects that fill space with a value at each point (the electric field, for instance, tells you how much force an electron will feel in different places). In classical physics, a field’s value can be zero everywhere so that it has no influence and contains no energy. “Classically, the vacuum is boring,” said Daniel Harlow, a theoretical physicist at the Massachusetts Institute of Technology. “Nothing is happening.”

But physicists learned that the universe’s fields are quantum, not classical, which means they are inherently uncertain. You’ll never catch a quantum field with exactly zero energy…

For an explanation of how key to understanding the origin and fate of the universe may be a more complete understanding of the vacuum: “How the Physics of Nothing Underlies Everything,” from @walkingthedot in @QuantaMagazine.

* attributed to Aristitole, and usually “translated,” as above, “Nature abhors a vacuum”

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As we noodle on nought, we might spare a thought for Hugo Gernsback, a Luxemborgian-American inventor, broadcast pioneer, writer, and publisher; he died on this date in 1967 at the age of 83.

Gernsback held 80 patents at the time of his death; he founded radio station WRNY, was involved in the first television broadcasts and is considered a pioneer in amateur radio.  But it was a writer and publisher that he probably left his most lasting mark:  In 1926, as owner/publisher of the magazine Modern Electrics, he filled a blank spot in his publication by dashing off the first chapter of a series called “Ralph 124C 41+.” The twelve installments of “Ralph” were filled with inventions unknown in 1926, including “television” (Gernsback is credited with introducing the word), fluorescent lighting, juke boxes, solar energy, television, microfilm, vending machines, and the device we now call radar.

The “Ralph” series was an astounding success with readers; and later that year Gernsback founded the first magazine devoted to science fiction, Amazing Stories.  Believing that the perfect sci-fi story is “75 percent literature interwoven with 25 percent science,” he coined the term “science fiction.”

Gernsback was a “careful” businessman, who was tight with the fees that he paid his writers– so tight that H. P. Lovecraft and Clark Ashton Smith referred to him as “Hugo the Rat.”

Still, his contributions to the genre as publisher were so significant that, along with H.G. Wells and Jules Verne, he is sometimes called “The Father of Science Fiction”; in his honor, the annual Science Fiction Achievement awards are called the “Hugos.”

(Coincidentally, today is also the birthday– in 1906– of Philo T. Farnsworth, the man who actually did invent television…)

Gernsback, wearing his invention, TV Glasses

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