(Roughly) Daily

Posts Tagged ‘quantum theory

“I’ve developed a new philosophy. I only dread one day at a time.”*…

 

Peanutz2

 

Starting [last] month, the very talented Adam Koford, the creator of Laugh-Out-Loud Cats webcomic, started posting these wonderful bootleg Peanuts comics to his Twitter account, and continued almost every day since.

Loose and sketchy, they capture the essence of Charles Schultz’ Peanuts so well: sweet and sad, combining childlike wonder and existential dread. As he went on, they started evolving a unique style of their own, distinct from the Peanuts characters but still recognizable….

Via Andy Baio‘s wonderful site Waxy.  The “Peanuts” panels are strewn through Adam’s Twitter feed; as a gift to us all, Baio collected a bunch of them into a Twitter “Moment.”

Enjoy… and don’t mention it to the Schultz estate.

* Charlie Brown

###

As we ruminate on reality, we might recall that today’s a relative-ly good day for it, as it was on this date in 1900 that German physicist Max Planck presented and published his study of the effect of radiation on a “black-body” substance (introducing what we’ve come to know as the Planck Postulate), and the quantum theory of modern physics– and for that matter, Twentieth Century modernity– were born.

Planck study demonstrated that in certain situations energy exhibits the characteristics of physical matter– something unthinkable at the time, when energy was thought to exist only in wave form– and suggested 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.

220px-Max_Planck_1933Max Planck

 

Written by LW

December 14, 2019 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

###

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.

source

Happy Birthday (1894), James Thurber!!

 

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

 

neutrino1-800x533

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”

###

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.

220px-Max_Planck_1933 source

 

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

###

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).

 source

 source

 

 

Written by LW

September 26, 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

###

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).

220px-James_R._Hoffa_NYWTS source

 

Written by LW

July 30, 2019 at 1:01 am

“Humanize your talk, and speak to be understood”*…

 

violet_personified

Personification is weird…yet entirely natural. It’s the odd practice of pretending things are people. When we personify, we apply human attributes to inanimate objects, to nature, to animals, or to abstract concepts, sometimes complete with dramatic stories about their social roles, emotions and intentions. We can observe this linguistically through features like unexpected pronoun use or certain animate verbs and adjectives that are usually only applied to people. A common example is how ships and other vessels traditionally have a feminine gender in English (even if the ship happens to be a “man-of-war“)… There’s a strange empathy in words like “she is alone” applied to an object that can’t possibly have a sense of loneliness. This isn’t the artifice of poetry, but everyday language. On the face of it, the concept of personification seems pretty crazy, the stuff of fantasy and magical thinking…

You might think, like many a respectable scientist, that it has no place in our earth logic, because not only is it not real, it is objectively false (and therefore unscientific), since inanimate objects do not have feelings or intentions (and if animals do, we can’t possibly know for sure). Yet personification is not only wildly popular in language use (even if we don’t always notice it), it’s a fascinating psychological phenomenon that reveals a lot about social cognition and how we might understand the world…

How the way we talk about the things around us both shapes and reflects our understanding of the world: “Personification Is Your Friend: The Language of Inanimate Objects.”

* Moliere

###

As we muse on anthropomorphic metaphor and meaning, we might recall that today’s a relative-ly good day for it, as it was on this date in 1900 that German physicist Max Planck presented and published his study of the effect of radiation on a “black-body” substance (introducing what we’ve come to know as the Planck Postulate), and the quantum theory of modern physics– and for that matter, Twentieth Century modernity– were born.

Planck study demonstrated that in certain situations energy exhibits the characteristics of physical matter– something unthinkable at the time– and suggested 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.

220px-Max_Planck_1933Max Planck

 

Written by LW

December 14, 2018 at 1:01 am

“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”*…

 

quantum computing

Quantum computing is all the rage. It seems like hardly a day goes by without some news outlet describing the extraordinary things this technology promises. Most commentators forget, or just gloss over, the fact that people have been working on quantum computing for decades—and without any practical results to show for it.

We’ve been told that quantum computers could “provide breakthroughs in many disciplines, including materials and drug discovery, the optimization of complex manmade systems, and artificial intelligence.” We’ve been assured that quantum computers will “forever alter our economic, industrial, academic, and societal landscape.” We’ve even been told that “the encryption that protects the world’s most sensitive data may soon be broken” by quantum computers. It has gotten to the point where many researchers in various fields of physics feel obliged to justify whatever work they are doing by claiming that it has some relevance to quantum computing.

Meanwhile, government research agencies, academic departments (many of them funded by government agencies), and corporate laboratories are spending billions of dollars a year developing quantum computers. On Wall Street, Morgan Stanley and other financial giants expect quantum computing to mature soon and are keen to figure out how this technology can help them.

It’s become something of a self-perpetuating arms race, with many organizations seemingly staying in the race if only to avoid being left behind. Some of the world’s top technical talent, at places like Google, IBM, and Microsoft, are working hard, and with lavish resources in state-of-the-art laboratories, to realize their vision of a quantum-computing future.

In light of all this, it’s natural to wonder: When will useful quantum computers be constructed? The most optimistic experts estimate it will take 5 to 10 years. More cautious ones predict 20 to 30 years. (Similar predictions have been voiced, by the way, for the last 20 years.) I belong to a tiny minority that answers, “Not in the foreseeable future.” Having spent decades conducting research in quantum and condensed-matter physics, I’ve developed my very pessimistic view. It’s based on an understanding of the gargantuan technical challenges that would have to be overcome to ever make quantum computing work…

Michel Dyakonov makes “The Case Against Quantum Computing.”

* Albert Einstein

###

As we feel the need for speed, we might recall that it was on this date in 1942 that a team of scientists led by Enrico Fermi, working inside an enormous tent on a squash court under the stands of the University of Chicago’s Stagg Field, achieved the first controlled nuclear fission chain reaction… laying the foundation for the atomic bomb and later, nuclear power generation.

“…the Italian Navigator has just landed in the New World…”
– Coded telephone message confirming first self-sustaining nuclear chain reaction, December 2, 1942.

Illustration depicting the scene on Dec. 2, 1942 (Photo copyright of Chicago Historical Society)

source

Indeed, exactly 15 years later, on this date in 1957, the world’s first full-scale atomic electric power plant devoted exclusively to peacetime uses, the Shippingport Atomic Power Station, reached criticality; the first power was produced 16 days later, after engineers integrated the generator into the distribution grid of Duquesne Light Company.

 source

 

Written by LW

December 2, 2018 at 1:01 am

%d bloggers like this: