Quantum Physics

[rynner2]

Now this is interesting:

Quantum mechanics rule 'bent' in classic experiment
By Jason Palmer, Science and technology reporter, BBC News

Researchers have bent one of the most basic rules of quantum mechanics, a counterintuitive branch of physics that deals with atomic-scale interactions.
Its "complementarity" rule asserts that it is impossible to observe light behaving as both a wave and a particle, though it is strictly both.
In an experiment reported in Science, researchers have now done exactly that.
They say the feat "pulls back the veil" on quantum reality in a way that was thought to be prohibited by theory.

Quantum mechanics has spawned and continues to fuel spirited debates about the nature of what we can see and measure, and what nature keeps hidden - debates that often straddle the divide between the physical and the philosophical.

For instance, a well-known rule called the Heisenberg uncertainty principle maintains that for some pairs of measurements, high precision in one necessarily reduces the precision that can be achieved in the other.

One embodiment of this idea lies in a "two-slit interferometer", in which light can pass through one of two slits and is viewed on a screen.
Let a number of the units of light called photons through the slits, and an interference pattern develops, like waves overlapping in a pond. However, keeping a close eye on which photons went through which slits - what may be termed a "strong measurement" - destroys the pattern.

Now, Aephraim Steinberg of the University of Toronto and his colleagues have sidestepped this limitation by undertaking "weak measurements" of the photons' momentum.

The team allowed the photons to pass through a thin sliver of the mineral calcite which gave each photon a tiny nudge in its path, with the amount of deviation dependent on which slit it passed through.
By averaging over a great many photons passing through the apparatus, and only measuring the light patterns on a camera, the team was able to infer what paths the photons had taken.

While they were able to easily observe the interference pattern indicative of the wave nature of light, they were able also to see from which slits the photons had come, a sure sign of their particle nature.
The trajectories of the photons within the experiment - forbidden in a sense by the laws of physics - have been laid bare.

On one level, the experiment appears to violate a central rule of quantum mechanics, but Professor Steinberg said this was not the case.
He explained to BBC News that "while the uncertainty principle does indeed forbid one from knowing the position and momentum of a particle exactly at the same time, it turns out that it is possible to ask 'what was the average momentum of the particles which reached this position?'" .
"You can't know the exact value for any single particle, but you can talk about the average."

Marlan Scully of Texas A&M University, a quantum physicist who has published on the idea of sneaking around this quantum limit before, said: "It's a beautiful series of measurements by an excellent group, the likes of which I've not seen before.
"This paper is probably the first that has really put this weak measurement idea into a real experimental realisation, and it also gave us the trajectories."

He said that the work would - inevitably - raise philosophical issues as well.
"The exact way to think about what they're doing will be researched for some time, and the weak measurement concept itself will be a matter of controversy - but now we have a very pretty experiment with these weak measurements," he added.

For his part, Professor Steinberg believes that the result reduces a limitation not on quantum physics but on physicists themselves.
"I feel like we're starting to pull back a veil on what nature really is," he said.
"The trouble with quantum mechanics is that while we've learned to calculate the outcomes of all sorts of experiments, we've lost much of our ability to describe what is really happening in any natural language.
"I think that this has really hampered our ability to make progress, to come up with new ideas and see intuitively how new systems ought to behave."

http://www.bbc.co.uk/news/science-environment-13626587

 

[Ghostisfort]

Once again, a statistical value has been applied to that which cannot be measured - just like the speed of light?
I recall an article in Astronomy Now or maybe it was Astronomy, where an astronomer calculated the speed of incoming cosmic particles to 13 decimal places. The speed of light is not known to anything like this accuracy as it's a statistical value.
I would dearly like to know, of what possible value is all of this to anyone but a mathematician looking for something to do?
I realise that it baffles the brains of the plebs, but this is all coming out in the open now. I think we are all starting to realise that we are being conned.
I can predict with some certainty that nothing useful to those who pay the bill, will ever be derived from this breath-taking discovery.
But, of course, I could be wrong and I await with baited breath for your destruction of my argument.

 

[ramonmercado]

Quantum computer leap
http://phys.org/news/2012-05-quantum.html
May 18th, 2012 in Physics / Quantum Physics

Dr André Carvalho. Photo by Dr Tim Wetherell.

(Phys.org) -- The main technical difficulty in building a quantum computer could soon be the thing that makes it possible to build one, according to new research from The Australian National University.

Dr André Carvalho, from the ARC Centre for Quantum Computation and Communication Technology and the Research School of Physics and Engineering, part of the ANU College of Physical and Mathematical Sciences, worked with collaborators from Brazil and Spain to come up with a new proposal for quantum computers. In his research, Dr Carvalho showed that disturbance – or noise – that prevents a quantum computer from operating accurately could become the very thing that makes it work.

“Most people have experienced some kind of computer error in their life – a file that doesn’t open, a CD that can’t be read – but we have ways to correct them. We also know how to correct errors in a quantum computer but we need to keep the noise level really, really low to do that,” he said.
“That’s been a problem, because to build a quantum computer you have to go down to atomic scales and deal with microscopic systems, which are extremely sensitive to noise.”

Surprisingly, the researchers found that the solution was to add even more noise to the system.

“We found that with the additional noise you can actually perform all the steps of the computation, provided that you measure the system, keep a close eye on it and intervene,” Dr Carvalho said.

“Because we have no control on the outcomes of the measurement – they are totally random – if we just passively wait it would take an infinite amount of time to extract even a very simple computation.

“It’s like the idea that if you let a monkey type randomly on a typewriter, eventually a Shakespearean play could come out. In principle, that can happen, but it is so unlikely that you’d have to wait forever.

“However, imagine that whenever the monkey types the right character in a particular position, you protect that position, so that any other typing there will not affect the desired character. This is sort of what we do in our scheme. By choosing smart ways to detect the random events, we can drive the system to implement any desired computation in the system in a finite time.”

Dr Carvalho said quantum information processing has the potential to revolutionise the way we perform computation tasks.

“If a quantum computer existed now, we could solve problems that are exceptionally difficult on current computers, such as cracking codes underlying Internet transactions.”

The research has been published in the journal Physical Review Letters.
More information: Quantum Computing with Incoherent Resources and Quantum Jumps, Phys. Rev. Lett. 108, 170501 (2012) DOI:10.1103/PhysRevLett.108.170501

Abstract

Spontaneous emission and the inelastic scattering of photons are two natural processes usually associated with decoherence and the reduction in the capacity to process quantum information. Here we show that, when suitably detected, these photons are sufficient to build all the fundamental blocks needed to perform quantum computation in the emitting qubits while protecting them from deleterious dissipative effects. We exemplify this by showing how to efficiently prepare graph states for the implementation of measurement-based quantum computation.
Provided by Australian National University

 

[Jerry_B]

Somewhat reminds me of how the Infinite Improbability Drive came into being...

 

[Xanatic*]

From a rather odd source comes confirmation that, as many suspected, Keanu Reeves is actually an immortal.

 

[Mythopoeika]

Keanu does look well preserved for a man over 50.

 

[rynner2]

That was brilliant! Entertaining and intellectual, and it was a quality production! Thanks, Xanatic!

 

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The Quantum World May Have a Favorite Flavor, Tantalizing Results Suggest

Source: livescience.com
Date: 3 January, 2020

The world of the teensy-tiny, the quantum realm, could have a favorite flavor.

We're not talking about itty-bitty ice cream cones, of course. The world of particles is split into three camps, called "flavors" (don't ask why). For example, the electrons represent one flavor, and there are two other particles with nearly identical properties, the muon and the tau, that have their own flavors. We've long suspected — but not proven — that all three flavors should be on equal footing.

But, alas, years of collider experiments are beginning to suggest that perhaps not everything is even-steven.

The results of these experiments are still tentative, and not significant enough to claim the firm discovery of a crack in the bible of particle physics called the Standard Model. However, if the results hold up, that could open the gateway to understanding everything from dark matter to the origins of the universe. You know, major unsolved problems in modern physics.

https://www-livescience-com.cdn.amp...ience.com/quantum-world-flavor-anomalies.html

 

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Scientists Find Evidence a Strange Group of Quantum Particles Are Basically Immortal

Source: sciencealert.com
Date: 4 January, 2004

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.

"Until now, the assumption was that quasiparticles in interacting quantum systems decay after a certain time," said physicist Frank Pollman of the Technical University of Munich back in June 2019.

https://www-sciencealert-com.cdn.am...p-of-quantum-particles-are-basically-immortal

 

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A quantum breakthrough brings a technique from astronomy to the nano-scale

Source: Columbia University/phys.org
Date: 3 January, 2020

Researchers at Columbia University and University of California, San Diego, have introduced a novel "multi-messenger" approach to quantum physics that signifies a technological leap in how scientists can explore quantum materials.

The findings appear in a recent article published in Nature Materials, led by A. S. McLeod, postdoctoral researcher, Columbia Nano Initiative, with co-authors Dmitri Basov and A. J. Millis at Columbia and R.A. Averitt at UC San Diego.

"We have brought a technique from the inter-galactic scale down to the realm of the ultra-small," said Basov, Higgins Professor of Physics and Director of the Energy Frontier Research Center at Columbia. Equipped with multi-modal nanoscience tools we can now routinely go places no one thought would be possible as recently as five years ago."

The work was inspired by "multi-messenger" astrophysics, which emerged during the last decade as a revolutionary technique for the study of distant phenomena like black hole mergers. Simultaneous measurements from instruments, including infrared, optical, X-ray and gravitational-wave telescopes can, taken together, deliver a physical picture greater than the sum of their individual parts.

https://phys-org.cdn.ampproject.org...akthrough-technique-astronomy-nano-scale.html

 

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Finding solutions amidst fractal uncertainty and quantum chaos

Math professor Semyon Dyatlov explores the relationship between classical and quantum physics.

Source: Jonathan Mingle | MIT News correspondent
Date: 25 January, 2020

Semyon Dyatlov calls himself a “mathematical physicist.”

He’s an associate editor of the journal Probability and Mathematical Physics. His PhD dissertation advanced understanding of wave decay in black hole spacetimes. And much of his research focuses on developing new ways to understand the correspondence between classical physics (which describes light as rays that travel in straight lines and bounce off surfaces) and quantum systems (wherein light has wave-particle duality).

So it may come as a surprise that, as a student growing up in Siberia, he didn’t study physics in depth.

“Much of my work is deeply related to physics, even though I didn’t receive that much physics education as a student,” he says. “It took when I started working as a mathematician to slowly start understanding things like general relativity and modern particle physics.”

http://news.mit.edu/2020/associate-professor-semyon-dyatlov-0126

 

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Quantum computers offer another look at classic physics concepts

Source: Brookhaven National Laboratory / phys.org
Date: 27 January, 2020

"Think what we can do if we teach a quantum computer to do statistical mechanics," posed Michael McGuigan, a computational scientist with the Computational Science Initiative at the U.S. Department of Energy's Brookhaven National Laboratory.

At the time, McGuigan was reflecting on Ludwig Boltzmann and how the renowned physicist had to vigorously defend his theories of statistical mechanics. Boltzmann, who proffered his ideas about how atomic properties determine physical properties of matter in the late 19th century, had one extraordinarily huge hurdle: atoms were not even proven to exist at the time. Fatigue and discouragement stemming from his peers not accepting his views on atoms and physics forever haunted Boltzmann.

Today, Boltzmann's factor, which calculates the probability that a system of particles can be found in a specific energy state relative to zero energy, is widely used in physics. For example, Boltzmann's factor is used to perform calculations on the world's largest supercomputers to study the behavior of atoms, molecules, and the quark "soup" discovered using facilities such as the Relativistic Heavy Ion Collider located at Brookhaven Lab and the Large Hadron Collider at CERN.

https://phys-org.cdn.ampproject.org...2020-01-quantum-classic-physics-concepts.html

 

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Wormholes Reveal a Way to Manipulate Black Hole Information in the Lab

Source: quantamagazine.org
Date: 27 February, 2020

Wormholes offer a way for information to escape the seemingly insurmountable grip of black holes.

As experimental proposals go, this one certainly doesn’t lack ambition. First, take a black hole. Now make a second black hole that is quantum entangled with it, which means that anything that happens to one of the black holes will seem to have an effect on the other, regardless of how far apart they are.

The rest sounds a bit easier, but a lot weirder. Feed some information into the first black hole, encoded in a quantum particle. As it falls beyond the event horizon — the point beyond which not even light can escape — the information is rapidly smeared throughout the black hole and is scrambled seemingly beyond recall.

But have patience — if you’ve linked the two black holes in the right way, after a short wait the quantum information will pop out of the second one, fully refocused into readable form. To get there, it will have traveled through a shortcut in space-time that links the two objects — a wormhole.

That, at least, is what physicists have predicted. Now a group led by Sepehr Nezami of the California Institute of Technology has suggested how to actually perform this extraordinary experiment — and they are beginning to work with collaborators to put the idea to the test.

https://www.quantamagazine.org/worm...e-black-hole-information-in-the-lab-20200227/

 

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The natural direction of heat flows—from hot to cold—can be reversed thanks to quantum effects

Source: sciencex.com
Date: 2 March, 2020

In a hot summer Sunday braai or shisa nyama (South African barbecue), if you don't finish your favorite beverage quickly, the ice cubes will melt and the drink will get warm—undoubtedly spoiling your braai/shisa nyama. That's because the natural direction of the heat is always from hot to cold (Fig. 1). The reverse, a drink that grows increasingly colder—which would definitively save your Sunday—looks like science fiction. Indeed, this would be like reversing the arrow of time. Our recent study establishes that things might be very different in the quantum world.

The ice cubes' fate in Fig. 1, summarized by the formula "the heat always flows from hot to cold," is a consequence of the second law of thermodynamics. Then, considering a quantum system interacting with its environment assumed to be initially hotter, the heat flow's direction is from the environment to the quantum system, as for your favorite drink. Things change when the quantum system is in a state presenting genuine quantum properties called quantum coherences. In particular, such quantum coherences are responsible for coherent superpositions, the central phenomenon around the famous Schrödinger's cat.

This deserves a short digression: Going back to the beginning of quantum mechanics, Schrödinger came up with a thought experiment aiming to highlight the unusual properties of the quantum world and to question its range of validity. Indeed, at the nanoscale, elementary particles can be found in coherent superposition of different states. For instance, an atom can be in a coherent superposition of excited state and ground state, which means that the atom is simultaneously in the excited state and in the ground state—fundamentally different from being either in the excited state or in the ground state.

https://sciencex.com/news/2020-03-natural-flowsfrom-hot-coldcan-reversed.html

 

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Superconductor transition switches single-molecule magnet

Source: physicsworld.com
Date: 4 Mar, 2020

A superconductor can switch the magnetic moment of a single-molecule magnet placed on top of it. This novel phenomenon, discovered by researchers in Italy, occurs because of quantum tunnelling of magnetic spins, and might be exploited in future quantum information technologies.

Single-molecule magnets are paramagnetic materials that can switch their magnetization between two states – “spin up” and “spin down”, for example. At low temperatures, these molecular complexes retain their magnetic state even in the absence of a magnetic field because reversing the magnetization would require them to overcome an energy barrier. This magnetic “memory” effect could be exploited in spintronics and quantum computing applications since the spins can act as stable quantum bits, or qubits.

According to study lead author Giulia Serrano, the combination of molecular magnets and superconductors is currently a hot research topic. Among other findings, researchers have discovered that monolayers of paramagnetic molecules can influence the temperature at which an adjacent layer of material becomes superconducting (that is, conducting electricity with no resistance). This change in the superconducting transition temperature Tc occurs because the paramagnetic monolayers create local states in the bandgap of the superconductor.

https://physicsworld.com/a/superconductor-transition-switches-single-molecule-magnet/

 

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Physicists take snapshots of quantum measurement

Source: phys.org
Date: 7 March, 2020

Anyone familiar with quantum mechanics knows that the act of measurement forces quantum systems into definite classical states. But new research shows that some measurements don’t destroy all quantum information in the process. It also reveals that measurements are not instantaneous, but instead gradually convert superposition states into classical ones.

The idea that all superposition is destroyed when a measurement is made was an underlying assumption of quantum mechanics as formulated by John von Neumann and others in the 1930s. Two decades later, however, Gerhart Lüders theorized that certain “ideal” measurements should only collapse superpositions of the specific states being probed, leaving others intact. In this way, he argued, a series of such measurements should preserve quantum coherence.

[...]

Repeating this process many times over, the researchers found that the excitation and emission destroyed all the superpositions related to the state being probed. The other superpositions, however, remained intact. According to Hennrich, this shows that he and his colleagues had indeed carried out an ideal measurement. What’s more, the fact that they did not need to detect the emitted photons shows that the measurement process does not depend on the presence of an observer. “It is already happening as a result of one fluorescence photon being emitted into the environment,” he says.

https://physicsworld.com/a/physicists-take-snapshots-of-quantum-measurement/

 

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‘Milestone’ Evidence for Anyons, a Third Kingdom of Particles

Source: quantamagazine.org
Date: 12 May, 2020

Anyons don’t fit into either of the two known particle kingdoms. To find them, physicists had to erase the third dimension.

Every last particle in the universe — from a cosmic ray to a quark — is either a fermion or a boson. These categories divide the building blocks of nature into two distinct kingdoms. Now researchers have discovered the first examples of a third particle kingdom.

Anyons, as they’re known, don’t behave like either fermions or bosons; instead, their behavior is somewhere in the middle. In a recent paper published in Science, physicists have found the first experimental evidence that these particles don’t fit into either kingdom. “We had bosons and fermions, and now we’ve got this third kingdom,” said Frank Wilczek, a Nobel prize–winning physicist at the Massachusetts Institute of Technology. “It’s absolutely a milestone.”

[...]

https://www.quantamagazine.org/milestone-evidence-for-anyons-a-third-kingdom-of-particles-20200512/

 

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Physicists exploit a quantum rule to create a new kind of crystal

Atoms can arrange themselves in regular configurations thanks to the Pauli exclusion principle

Scientists created a new type of crystal, based only on a quantum rule called the Pauli exclusion principle, by using lasers to confine lithium atoms (illustrated at center) to a region within a vacuum chamber.

Source: sciencenews.org
Date: 19 May, 2020

Physicists have harnessed the aloofness of quantum particles to create a new type of crystal.

Some particles shun one another because they are forbidden to take on the same quantum state as their neighbors. Atoms can be so reluctant to overlap that they form a crystal-like arrangement even when they aren’t exerting any forces on one another, physicists report May 8 at arXiv.org. Called a Pauli crystal, the configuration is the result of a quantum mechanical rule called the Pauli exclusion principle.

Scientists had previously predicted the existence of Pauli crystals, but no one had observed them until now. “It just teaches us how beautiful physics is,” says quantum physicist Tilman Esslinger of ETH Zurich. The experiment reveals there are still new phenomena to be observed from a foundational principle taught in introductory physics classes. “If I wrote a textbook,” Esslinger says, “I would put that [experiment] in.”

Although the Pauli crystals themselves are based on known physics, the technique used to observe them could help scientists better understand certain mysterious states of matter, such as superconductors, materials that conduct electricity without resistance, or superfluids, which flow without friction.

[...]

https://www.sciencenews.org/article/physicists-exploit-quantum-rule-create-new-pauli-crystal/

 

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Scientists Just Found a Way to Make Quantum States Last 10,000 Times Longer

DAVID NIELD
16 AUGUST 2020
www-sciencealert-com

One of the major challenges in turning quantum technology from potential to reality is getting super-delicate quantum states to last longer than a few milliseconds – and scientists just raised the bar by a factor of about 10,000.

They did it by tackling something called decoherence: that's the disruption from surrounding noise caused by vibrations, fluctuations in temperature, and interference from electromagnetic fields that can very easily break a quantum state,

"With this approach, we don't try to eliminate noise in the surroundings," says quantum engineer Kevin Miao, from the University of Chicago. "Instead, we trick the system into thinking it doesn't experience the noise."

By applying a continuous alternating magnetic field to a type of quantum system called a solid-state qubit, in addition to the standard electromagnetic pulses required to keep such a system under control, the team was able to 'tune out' unnecessary noise.

The researchers compare it to sitting on a merry go round – the faster you go, the less able you are to hear the noise of your surroundings, as it all blurs into one. In this case spinning electrons are the merry go round.

[...]

https://www.sciencealert.com/scient...tum-states-lasting-up-to-10-000-times-longer/

 

[Anonymous34905]

Scientists Just Found a Way to Make Quantum States Last 10,000 Times Longer

DAVID NIELD
16 AUGUST 2020
www-sciencealert-com

One of the major challenges in turning quantum technology from potential to reality is getting super-delicate quantum states to last longer than a few milliseconds – and scientists just raised the bar by a factor of about 10,000.

They did it by tackling something called decoherence: that's the disruption from surrounding noise caused by vibrations, fluctuations in temperature, and interference from electromagnetic fields that can very easily break a quantum state,

"With this approach, we don't try to eliminate noise in the surroundings," says quantum engineer Kevin Miao, from the University of Chicago. "Instead, we trick the system into thinking it doesn't experience the noise."

By applying a continuous alternating magnetic field to a type of quantum system called a solid-state qubit, in addition to the standard electromagnetic pulses required to keep such a system under control, the team was able to 'tune out' unnecessary noise.

The researchers compare it to sitting on a merry go round – the faster you go, the less able you are to hear the noise of your surroundings, as it all blurs into one. In this case spinning electrons are the merry go round.

[...]

https://www.sciencealert.com/scient...tum-states-lasting-up-to-10-000-times-longer/

I really wish that I had a much more mathematical and scientific brain to understand all this.

I find it incredibly fascinating but often my brain just melts into confusion

 

[Comfortably Numb]

I find it incredibly fascinating but often my brain just melts into confusion

Quantum Physics, eh... what's that all about?

Apparently:

"The quantum world is a pretty wild one, where the seemingly impossible happens all the time: Teensy objects separated by miles are tied to one another, and particles can even be in two places at once. But one of the most perplexing quantum superpowers is the movement of particles through seemingly impenetrable barriers".

"Quantum tunneling is a phenomenon where an atom or a subatomic particle can appear on the opposite side of a barrier that should be impossible for the particle to penetrate. It's as if you were walking and encountered a 10-foot-tall (3 meters) wall extending as far as the eye can see. Without a ladder or Spider-man climbing skills, the wall would make it impossible for you to continue".


If you're Spiderman, you can go straight through walls?

However, being in 'Two places at the one time'..

So you can be in the bookies and still in the pub?

Aye, right... these people must think we're eejits...

New subscriber, WSL? if so, Quantum physics isn't the easiest - kind of like jumping in the deep end attached to a battle tank!

 

[Anonymous34905]

Quantum Physics, eh... what's that all about?

Apparently:

"The quantum world is a pretty wild one, where the seemingly impossible happens all the time: Teensy objects separated by miles are tied to one another, and particles can even be in two places at once. But one of the most perplexing quantum superpowers is the movement of particles through seemingly impenetrable barriers".

"Quantum tunneling is a phenomenon where an atom or a subatomic particle can appear on the opposite side of a barrier that should be impossible for the particle to penetrate. It's as if you were walking and encountered a 10-foot-tall (3 meters) wall extending as far as the eye can see. Without a ladder or Spider-man climbing skills, the wall would make it impossible for you to continue".


If you're Spiderman, you can go straight through walls?

However, being in 'Two places at the one time'..

So you can be in the bookies and still in the pub?

Aye, right... these people must think we're eejits...

New subscriber, WSL? if so, Quantum physics isn't the easiest - kind of like jumping in the deep end attached to a battle tank!

Lol!! Yup, a new subscriber and definitely I chose a tricky subject for my first post!!

I watched a BBC documentary on it.

The closest I got to making sense of it was when they said it was like having a choice of 1 or 2 but also 1 & 2 at the same time.

Normal computers were 1 or 2 but quantum ones could be a mix of the 2 as well as separate.

And then the rest went over my head!

 

[Comfortably Numb]

Lol!! Yup, a new subscriber and definitely I chose a tricky subject for my first post!!

I watched a BBC documentary on it.

... Normal computers were 1 or 2 but quantum ones could be a mix of the 2 as well as separate.

And then the rest went over my head!

"I watched a BBC documentary on it".

Aye, thought as much...

That's where my problems started as well - probably part of the 'Horizon' series.

Between that and 'How Big is the Universe', 'How Small is the Universe', 'Parallel Universes' and one of my favourites, 'How Long is a Piece of String', etc., I (genuinely) came to realise it all, 'jist wisnae for the likes o' us tae ken'...

You have however raised an important point re same, it might be helpful for others to find one page with links to some of the most profound of these. Last time I looked into it, some of them were prohibited on YouTube because of copyright.

Which brings us to a seperate posting I am about to make.

It's a reported breakthrough concerning
'Time Crystals...'.

Would that possibly not only be yourself thinking, Time Crystals... shall I be following this with an update on latest research developments re Sonic Screwdrivers or, perhaps Dilithium Crystals...

 

[Anonymous34905]

"I watched a BBC documentary on it".

Aye, thought as much...

That's where my problems started as well - probably part of the 'Horizon' series.

Between that and 'How Big is the Universe', 'How Small is the Universe', 'Parallel Universes' and one of my favourites, 'How Long is a Piece of String', etc., I (genuinely) came to realise it all, 'jist wisnae for the likes o' us tae ken'...

You have however raised an important point re same, it might be helpful for others to find one page with links to some of the most profound of these. Last time I looked into it, some of them were prohibited on YouTube because of copyright.

Which brings us to a seperate posting I am about to make.

It's a reported breakthrough concerning
'Time Crystals...'.

Would that possibly not only be yourself thinking, Time Crystals... shall I be following this with an update on latest research developments re Sonic Screwdrivers or, perhaps Dilithium Crystals...

Yes, it was horizon on BBC4!!

 

[Comfortably Numb]

Oh boy... Schrödinger's cat amongst the pigeons...?

Physicists Just Found a New Quantum Paradox That Casts Doubt on a Pillar of Reality

Source: The Conversation
Date: 28 August, 2020

If a tree falls in a forest and no one is there to hear it, does it make a sound? Perhaps not, some say.

And if someone is there to hear it? If you think that means it obviously did make a sound, you might need to revise that opinion.

We have found a new paradox in quantum mechanics – one of our two most fundamental scientific theories, together with Einstein's theory of relativity – that throws doubt on some common-sense ideas about physical reality.

Take a look at these three statements:

When someone observes an event happening, it really happened.

It is possible to make free choices, or at least, statistically random choices.

A choice made in one place can't instantly affect a distant event. (Physicists call this "locality".)

These are all intuitive ideas, and widely believed even by physicists. But our research, published in Nature Physics, shows they cannot all be true – or quantum mechanics itself must break down at some level.

This is the strongest result yet in a long series of discoveries in quantum mechanics that have upended our ideas about reality. To understand why it's so important, let's look at this history.

[...]

https://www.sciencealert.com/a-new-...foundations-of-observed-reality-into-question

 

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Why there is no speed limit in the superfluid universe

Source: phys.org
Date: 21 September, 2020

Helium-3 is a rare isotope of helium, in which one neutron is missing. It becomes superfluid at extremely low temperatures, enabling unusual properties such as a lack of friction for moving objects.

It was thought that the speed of objects moving through superfluid helium-3 was fundamentally limited to the critical Landau velocity, and that exceeding this speed limit would destroy the superfluid. Prior experiments in Lancaster have found that it is not a strict rule and objects can move at much greater speeds without destroying the fragile superfluid state.

Now scientists from Lancaster University have found the reason for the absence of the speed limit: exotic particles that stick to all surfaces in the superfluid.

The discovery may guide applications in quantum technology, even quantum computing, where multiple research groups already aim to make use of these unusual particles.

To shake the bound particles into sight, the researchers cooled superfluid helium-3 to within one ten thousandth of a degree from absolute zero (0.0001K or -273.15°C). They then moved a wire through the superfluid at a high speed, and measured how much force was needed to move the wire. Apart from an extremely small force related to moving the bound particles around when the wire starts to move, the measured force was zero.

Lead author Dr. Samuli Autti said: "Superfluid helium-3 feels like vacuum to a rod moving through it, although it is a relatively dense liquid. There is no resistance, none at all. I find this very intriguing."

[...]

https://www.phys.org/news/2020-09-limit-superfluid-universe.amp

 

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Quantum Tunnels Show How Particles Can Break the Speed of Light

Recent experiments show that particles should be able to go faster than light when they quantum mechanically “tunnel” through walls.

Source: Quantamagazine
Date: October 20, 2020

No sooner had the radical equations of quantum mechanics been discovered than physicists identified one of the strangest phenomena the theory allows.

“Quantum tunneling” shows how profoundly particles such as electrons differ from bigger things. Throw a ball at the wall and it bounces backward; let it roll to the bottom of a valley and it stays there. But a particle will occasionally hop through the wall. It has a chance of “slipping through the mountain and escaping from the valley,” as two physicists wrote in Nature in 1928, in one of the earliest descriptions of tunneling.

Physicists quickly saw that particles’ ability to tunnel through barriers solved many mysteries. It explained various chemical bonds and radioactive decays and how hydrogen nuclei in the sun are able to overcome their mutual repulsion and fuse, producing sunlight.

But physicists became curious — mildly at first, then morbidly so. How long, they wondered, does it take for a particle to tunnel through a barrier?

The trouble was that the answer didn’t make sense.

The first tentative calculation of tunneling time appeared in print in 1932. Even earlier stabs might have been made in private, but “when you get an answer you can’t make sense of, you don’t publish it,” noted Aephraim Steinberg, a physicist at the University of Toronto.

It wasn’t until 1962 that a semiconductor engineer at Texas Instruments named Thomas Hartman wrote a paper that explicitly embraced the shocking implications of the math.

Hartman found that a barrier seemed to act as a shortcut. When a particle tunnels, the trip takes less time than if the barrier weren’t there. Even more astonishing, he calculated that thickening a barrier hardly increases the time it takes for a particle to tunnel across it. This means that with a sufficiently thick barrier, particles could hop from one side to the other faster than light traveling the same distance through empty space.

In short, quantum tunneling seemed to allow faster-than-light travel, a supposed physical impossibility.

“After the Hartman effect, that’s when people started to worry,” said Steinberg.

[...]

https://www.quantamagazine.org/quantum-tunnel-shows-particles-can-break-the-speed-of-light-20201020/

 

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In a Mind-Bending New Paper, Physicists Give Schrodinger's Cat a Cheshire Grin

Source: sciencealert.com
Date: 11 December, 2020

"I've often seen a cat without a grin," thought Alice. "But a grin without a cat! It's the most curious thing I ever saw in all my life!"

It's an experience eminent physicist Yakir Aharonov can relate to. Together with fellow Israeli physicist Daniel Rohrlich, he's shown theoretically how a particle might show its face in a corner of an experiment without needing its body anywhere in sight.

To be more precise, their analysis argues information could be transferred between two points without an exchange of particles.

The theory dates back to 2013 when researchers based in the US and Saudi Arabia suggested a kind of freezing effect applied to a quantum wave still might not be enough to stop it from transmitting information.

"We found it extremely interesting – the possibility of communication without anything passing between the two people who communicate with each other," Aharonov explained to Anna Demming at Phys.org.

"And we wanted to see if we can understand it better."

The experimental model they base their calculations on is surprisingly simple.

Think of a corridor with one end capped in a mirrored door. In quantum physics, where objects aren't defined until observed, the door is both open and closed until it's seen, not unlike the condemned cat in Schrödinger's proposed thought experiment.

If a particle were to be sent down the corridor, its fate would also be a blur of possibility until its journey was made known. It would reflect and not reflect. Pass and not pass.

That's because the particle's wave of possibility has characteristics of any physical wave. There are crests and troughs governing the chances of the particle being found somewhere, and phases as it evolves over time.

Putting it simply, a part of the particle's phase describing its angular momentum, or spin, should change in relation to the opened or closed state of the mirror, according to the physicists.

Even when the particle itself should be nowhere near that end of the corridor, Aharonov and Rorlich found that it's almost as if the momentum should be capable of reaching out with a ghostly finger to touch the closed door, before carrying back a bit of information with it.

Particles aren't typically known to let go of things like spin or charge, to have them wander away and affect distant surroundings, no more than a smile is known to remain while a face makes an exit.

"If you're talking about a cat and its grin, that's very strange," Rorlich told Demming over at Phys.org.

"But of course, all of this has to translate back to elementary particles, and if an elementary particle loses its spin because its spin goes somewhere else – maybe that's something we can get used to."

[...]

https://www.sciencealert.com/schrod...in-in-a-mind-bending-quantum-physics-analysis

 

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... and if an elementary particle loses its spin because its spin goes somewhere else...

 

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Physicists Suggest All Matter May Be Made Up of Energy 'Fragments'

Source: sciencealert.com
Date: 11 December, 2020

Matter is what makes up the Universe, but what makes up matter? This question has long been tricky for those who think about it – especially for the physicists.

Reflecting recent trends in physics, my colleague Jeffrey Eischen and I have described an updated way to think about matter. We propose that matter is not made of particles or waves, as was long thought, but – more fundamentally – that matter is made of fragments of energy.

The ancient Greeks conceived of five building blocks of matter – from bottom to top: earth, water, air, fire and aether. Aether was the matter that filled the heavens and explained the rotation of the stars, as observed from the Earth vantage point.

These were the first most basic elements from which one could build up a world. Their conceptions of the physical elements did not change dramatically for nearly 2,000 years.

Then, about 300 years ago, Sir Isaac Newton introduced the idea that all matter exists at points called particles. One hundred fifty years after that, James Clerk Maxwell introduced the electromagnetic wave – the underlying and often invisible form of magnetism, electricity and light.

The particle served as the building block for mechanics and the wave for electromagnetism – and the public settled on the particle and the wave as the two building blocks of matter. Together, the particles and waves became the building blocks of all kinds of matter.

This was a vast improvement over the ancient Greeks' five elements but was still flawed. In a famous series of experiments, known as the double-slit experiments, light sometimes acts like a particle and at other times acts like a wave. And while the theories and math of waves and particles allow scientists to make incredibly accurate predictions about the Universe, the rules break down at the largest and tiniest scales.

Einstein proposed a remedy in his theory of general relativity. Using the mathematical tools available to him at the time, Einstein was able to better explain certain physical phenomena and also resolve a longstanding paradox relating to inertia and gravity.

But instead of improving on particles or waves, he eliminated them as he proposed the warping of space and time.

Using newer mathematical tools, my colleague and I have demonstrated a new theory that may accurately describe the Universe. Instead of basing the theory on the warping of space and time, we considered that there could be a building block that is more fundamental than the particle and the wave.

[...]

https://www.sciencealert.com/physic...-to-describe-matter?__twitter_impression=true