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Physics Nobel Prize in a superposition between three quantum physicists

(2022/10/05)


Physicists Alain Aspect, John Clauser and Anton Zeilinger were awarded the Nobel Prize in Physics this week for performing breakthrough quantum entanglement experiments.

Quantum entanglement is a phenomenon in which a group of particles share a quantum state even when they are physically separate over some distance. Measuring the momentum, spin, or polarization of one particle instantaneously affects and determines the state of other entangled particles in the same system.

The nature of entanglement was fiercely debated among physicists. Some thought information could not travel faster than the light and there must be some other process impacting the particles in the system while others believed the weird phenomena showed a breakdown in classical physics, paving the way for quantum mechanics.

[1]

In 1964, John Stewart Bell came up with a theoretical framework that tests if the entanglement effects were due to some hidden variables affecting the entangled particles. Bell's inequalities describe the mathematical constraints an entangled system must obey if it is affected by these local hidden variables.

[2]

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The trio of boffins who bagged the Nobel Prize for Physics this week did so, we're told, "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science." That means they proved quantum entangled was an inherent property of the particles; that hidden variables do not impact the outcome of measurements.

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From left, Alain Aspect, John Clauser and Anton Zeilinger ... Image Credit: Niklas Elmehed © Nobel Prize Outreach

Clauser, 79, and Aspect, 75, performed the initial experiments proving that entangled particles violated Bell's inequalities in separate projects conducted in the US and France. Zeilinger, 77, later applied the results in other experiments demonstrating other entanglement-related effects such as quantum teleportation of a qubit.

"It has become increasingly clear that a new kind of quantum technology is emerging," Anders Irbäck, chair of the Nobel Committee for Physics, [5]said on Tuesday. "We can see that the laureates' work with entangled states is of great importance, even beyond the fundamental questions about the interpretation of quantum mechanics."

[6]You're not wrong. The scope for quantum computers remains small

[7]Nobel Prizes in Physics and Chemistry awarded to boffins studying complex systems, organic catalysts

[8]It's in their DNA: Nobel Prize in chemistry goes to pioneers of the CRISPR gene-editing tool

[9]Massive news, literally: Three super-boffins awarded Nobel Prize in physics for their black-hole breakthroughs

Meanwhile, the Nobel Prize in Physiology was [10]won by Swede Svante Pääbo "for his discoveries concerning the genomes of extinct hominins and human evolution." The evolutionary geneticist sequenced the genomes of Neanderthals and discovered Denisovans, another ancient human ancestor species using DNA analysis.

He showed that genes transferred between these hominins as they migrated from Africa 70,000 years ago affected the biological functions of modern Homo sapiens today, such as how our immune systems defend against infections.

Pääbo, 67, will scoop the total ten million Swedish Kronor prize, worth over $900,000 or £800,000, for the Nobel Prize in Physiology, whilst Aspect, Clauser and Zeilinger will split the same amount for the Nobel Prize in Physics equally. ®

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[4] https://regmedia.co.uk/2022/10/04/nobel_prize_physics_2022.jpg

[5] https://www.nobelprize.org/prizes/physics/2022/prize-announcement/

[6] https://www.theregister.com/2022/07/21/quantum_computing/

[7] https://www.theregister.com/2021/10/07/nobel_physics_chemistry/

[8] https://www.theregister.com/2020/10/08/nobel_prize_chemistry/

[9] https://www.theregister.com/2020/10/07/nobel_prize_physics/

[10] https://www.nobelprize.org/prizes/medicine/2022/prize-announcement/

[11] https://whitepapers.theregister.com/



Measuring a property does not set it...

Anonymous Coward

You're not even looking at a photon, you're looking at the net effect of a photon on a detector.

That's why you have red-shift/blue-shift, because the motion of the detector forms part of the property of the photon. The energy imparted depends on the motion of the matter, hence blue light has more energy than red.

So in your head, you set the properties of the photon by measuring them, but in reality those were neither properties of the photon, nor independent of one another....

The light doesn't carry all of the properties (here I'm mentioning its apparent energy changing for red/blue shift), it's properties are NET EFFECTS between the photon and the detectors.

Its also true for other properties too, not just the photons energy, and the corresponding net frequency.

Take two such net oscillations, one in the photon and one in the detector, you now have a net spin, (a photons circular polarization property, or the spin of a particle).

So when measured by detector electron D1, the photon has NetSpin(D1,Photon), but when measured relative to electron D2, our photon has a different value NetSpin(D2,Photon) and so on.

The photon appears to have lots of different NetSpin properties, all at the same time, depending on which detecting electron it is being measured with.

This is the mechanism of Superposition. The photon has lots of spin properties all at the same time.

When the photon is captured by a particular electron, e.g. D2, then NetSpin(D2, Photon) will dominate and it appears to have that spin property.

So two 'entangled' photons, P and Q. They can have the same component of oscillation, and yet when you measure them with different detectors the spin property is different, for different detectors.

What's more if you compare spin property to other properties, there appears to be no correlation.

Properties that, common sense should be related (e.g. up/down left/right polarization and spin), don't seem to correlate to others (like circular polarization).

So you hypothesize that NetSpin must be an independent property.

P and Q head in different directions across the universe.

Photon P is measured by a detector DP, and each time the experiment is performed you get a result (DP1, DP2, DP3, ...DPn) for n experiments.

Photon Q is measured by a detector DQ, and each time the experiment is performed you get a result (DQ1, DQ2, DQ3,....DQn)

Now the magic happens, you want P and Q to be entangled, so you filter for some net properties that are the same.

Perhaps its frequency, perhaps some other motion, some net property NetProp, that you have decided doesn't correlate to NetSpin and thus is 'independent'.

So perhaps in experiment 3, NetProp(P3, DP3) = to NetProp(Q3, DQ3), you decide that the third experiment was successful entanglement, while the others were unsuccessful entanglement.

And now you find also that other properties, like our spin property NetSpin(P,DP3) is equal to NetSpin(Q,DQ3).

AMAZING! you say, for entangled photons P3 and Q3, the act of measuring NetSpin(P3) set the NetSpin to be the same for Q3!

Yet it's impossible, P and Q are across the universe and not connected, but it must be true, because there is no other explanation! (bs).

But P and Q always had the same oscillating component, they were really always 'entangled'.

What you did was filter for the subset of where the *detectors* are oscillating the same way.

The photons, had the same properties, and you've filtered for the detectors that had the same properties, so now ALL the DERIVED properties between photon and detector are now the same.

The only information that travelled across the universe was your "filter for experiment 3" signal!

THE ACT OF MEASURING NetSpin(P3,DP3) DID NOT SET THAT PROPERTY IN PHOTON Q3. The spin property was never a property of P and Q, it was a NET EFFECT of P and Q on a detector.

You could calculate the energy in this net spin too. You could pretend the energy of that spin is carried in the photon. Some sort of angular momentum, or spin momentum perhaps?

But the spin is a net effect, and the apparent energy in that spin is a net effect. Each detector would detect a different 'spin momentum' energy in the photon.

THERE IS NO ENERGY STORES LIKE MOMENTUM, ANGULAR MOMENTUM, and so on, that somehow cause a motion to occur. Because each detector detects different spins, the energy would be different for each, the energy is not carried solely by the photon.

Hence blue light imparts more energy than red-light, even if the blue-light is the same red-light shifted by motion of the detector.

[All entanglement experiments have two flaws: some sort of filtering and the statistical test (e.g. Bells) done on the filtered subset after you've filtered. The information that travels is the filtering signal.]

Re: Measuring a property does not set it...

Anonymous Coward

While we're here, have a look at one of those motions of the photon, its apparent "constant speed" in a vacuum property.

c cannot be a constant.

Given the above (motion effects are net effects, a particle's net motion appears to differ depending on which detector is viewing it), the apparent position of a particle or photon is also a net effect.

[A particles cannot start in one place, move in different directions, and yet end up at the same place.

Since the motion depends on the detector, and the same particle can appear to have different motion for different detectors, so the position those detectors see is different].

You see this as tunneling effects in semiconductors, relative to individual atoms, the electron appears to be in different places. Position must be another net effect.

So, now lets look at the photon, its position depends on the detector detecting it, it cannot be travelling at a constant speed c independent of the matter around it, because different detectors would detect the photon in different places.

So c is not a constant.

Yet it appears to be.

Imagine the earth flying through space, left to right, the velocity of light relative to the earth should depend on which direction you measure it.

Measure IN THE SAME DIRECTION OF THE MOTION OF THE EARTH and it should be less, racing along side earth.

Measure IN THE OPPOSITE DIRECTION and it should be more, the earth and light moving apart, both contributing to the motion.

But it doesn't. It always appears to be c.

If it moves 100 atoms in time t, those 100 atoms much be squashed in the direction of travel, such that when you measure light in that direction, its motion is slower, and the atoms must be squashed, so it still travels 100 atoms in that time in that direction. And conversely in the opposing direction, atoms must be stretched.

So the mechanism of motion that gives atoms their size and dimensions must be the *same* mechanism that light moves with. So that the two properties are affected equally. Both types of motion are the same type of motion, one a repeating pattern that loops back, matter, the other not, light.

Hence light only *appears* to be a constant when compared to matter, because both are changed by the motion.

Hence the magical constant c is not the actual speed of light, but only the same when you measure it against the local matter it is travelling alongside.

[Side note: Black hole guys, boundary case: you think the event horizon is in a fixed position relative to the black hole? Nope. From the above, the real speed-of-light depends on the observer. A different observer with a different motion, has a different speed-of-light, and perceives the event horizon in a different place.

So as you fall into the black hole the event horizon moves, it shifts with you. The set of stars you see, are a sliding window around you, new stars appear and disappear, they still exist, they're just not within your local event horizons.]

Re: Measuring a property does not set it...

lglethal

I see that you have heard of paragraphs, but I'm not sure if you've quite understood how they actually work...

Anyway, I havent bothered to read what you've written because clearly anyone who writes like that cannot be relied upon to make a salient and accurate point. The only thing missing is multiple exclamation marks...

Re: Measuring a property does not set it...

DJO

I don't think you quite understand what the term "spin" means when applied to sub-atomic particles.

Re: Measuring a property does not set it...

TheRealRoland

You feel you deserved the prize, didn't you?

lglethal

Whenever I hear about Quantum Entanglement, I cant help but think of the following Terry Pratchett quote:

"The only thing known to go faster than ordinary light is monarchy, according to the philosopher Ly Tin Wheedle. He reasoned like this: you can't have more than one king, and tradition demands that there is no gap between kings, so when a king dies the succession must therefore pass to the heir instantaneously. Presumably, he said, there must be some elementary particles -- kingons, or possibly queons -- that do this job, but of course succession sometimes fails if, in mid-flight, they strike an anti-particle, or republicon. His ambitious plans to use his discovery to send messages, involving the careful torturing of a small king in order to modulate the signal, were never fully expanded because, at that point, the bar closed.”

May the bar remain wide open for these bright Boffins...

79, 75, 77

Pascal Monett

It's called work, whippersnappers. A lifetime of it.

Kardashians they are not.

So subspace is for real?

Potemkine!

If instantaneous communication is indeed possible, it will be a revolution for space communications.

== Bring us Dabbsy back! ==

Re: So subspace is for real?

DJO

You cannot use entanglement to transmit data. It's not possible to set a property of one particle to affect a separate one, you can read one and infer the properties of the other but not in a way that can pass data between the two. Once the waveform is collapsed and the properties of one particle read and the other inferred the entanglement is permanently broken.

It's a shame but physics is like that.

TeeCee

Alain Aspect, John Clauser and Anton Zeilinger

..may be happy now, but just wait until the prize collapses into a known state and two of them miss out.

b0llchit

That is why you can never look or collect your prized prize!

Or,... one will get the prize, one will get the anti-prize and one will have peeked and gone empty.

Make a wish, it might come true.