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Back to some Real Quantum Mechanics - Quantum Interference - The Movie...

Paul
user 2439713
Sydney, AU
Post #: 45
From PhysicsWorld.com, March 29, 2012

http://physicsworld.c...­

The youtube video alluded to in the text can be found at - http://www.youtube.co...­

The first real-time movie of large molecules creating an interference pattern after passing through two slits has been made by an international team of physicists. As well as being a beautiful example of the wave–particle duality of quantum mechanics, the technique could provide further insight into the boundaries between quantum and classical physics.

The build-up of an interference pattern as individual particles pass through two side-by-side slits in a screen is one of the most famous examples of how an entity such as an electron can behave both as a particle and a wave. This research has its roots in the famous double-slit experiment carried out by Thomas Young in the early 1800s. When Young shone light through his apparatus, he saw a pattern of bright and dark fringes that could only be explained by the interference of wavefronts. In the 1920s it was shown that the same occurred to electrons, establishing the concept of wave–particle duality. More recently, similar behavior has been seen using molecules containing as many as 400 atoms.

Physicists have also shown that individual particles create an interference pattern that builds up as they pass through the slits one by one and then arrive at a detector. This confirms that each individual particle does indeed behave like a wave as it passes through the slits. Observing this behaviour in large molecules is particularly interesting because it allows researchers to investigate whether there is a threshold at which particles stop behaving like waves and begin to obey the classical laws of physics.
Innovative interference

Now, physicists at institutes in Austria, Israel, Switzerland and Germany have watched in real time as interference patterns were created by 58-atom phthalocyanine molecules (C32H18N8) and 114-atom phthalocyanine derivatives (C48H26F24N8O8) – the latter being the largest ever molecule to be studied in this way. The molecules were produced using micro-evaporation, in which a laser was focused on a thin layer of the compound. This reduced the heat load to the sample, preventing the molecules from decomposing and providing the researchers with an intense and coherent beam of large organic molecules.

The team also created a silicon-nitride diffraction grating with a separation of 100 nm between slits. This ensured that the diffraction angle was large enough to be resolved after the molecules passed through the slits. Furthermore, the grating was just 10 nm thick – around 16 times thinner than previous gratings – in order to reduce interactions between the molecules and the grating material.

Another important innovation was the use of fluorescence microscopy to detect the molecules. This involved exciting the molecules with a laser, and their emitted light was imaged onto an electron-multiplying charge-coupled device (EMCCD) camera. This technique, which allowed each molecule's position to be determined with an accuracy of 10 nm, was around 10,000 times more sensitive than previous detection methods.
A textbook pattern

The end product is a movie showing the gradual build-up of the quantum interference pattern over 90 min, with each molecule appearing as a fluorescent speck against the dark background.

"The arrival of each single radiating molecule is objectively unpredictable and yet the ensemble reveals the perfect deterministic interference pattern," says team member Markus Arndt from the University of Vienna. "Previous experiments could see interference but they were not able to store the particles on a detector for future analysis. Fluorescence imaging visualizes the particle nature of the molecules much better than any of the earlier methods and it can do that for hours after the experiment."

The team used these images to plot 1D diffraction curves, integrating the patterns over a section of the molecules' velocity distribution. As expected, the curves show a strong central peak, surrounded by weaker secondary peaks – described by the researchers as a "textbook-like diffraction of plane waves at a grating".
Quantum limits

"Studying quantum interference of large molecules is important because it is a way to explore how far the realm of quantum behaviour can be extended to macroscopic objects," says Wieland Schöllkopf, a physicist at the Fritz-Haber-Institut der Max-Planck-Gesellschaft in Berlin who was not involved in the study. "I think with ever more ingenious experimental techniques like, for instance, the nanotechnologies used by the Vienna group, it will be possible to push the limits further and further."

Arndt believes that their technologies can now be scaled up to higher molecular masses. "Quantum mechanics has never been tested for this parameter regime and it is the task of experimentalists to explore the unexplored," says Arndt. "Whether our world is purely quantum or whether there is a factual transition to classical physics is open to future experiments."

The research is described in Nature Nanotechnology.

A video of the movie can be viewed here.
About the author

James Lloyd is a science writer based in the UK
lan B.
user 10895495
London, GB
Post #: 151



The build-up of an interference pattern as individual particles pass through two side-by-side slits in a screen is one of the most famous examples of how an entity such as an electron can behave both as a particle and a wave. This research has its roots in the famous double-slit experiment carried out by Thomas Young in the early 1800s. When Young shone light through his apparatus, he saw a pattern of bright and dark fringes that could only be explained by the interference of wavefronts. In the 1920s it was shown that the same occurred to electrons, establishing the concept of wave–particle duality.

(Hmmm .. I have read in more than 1 textbook that the first researchers to achieve that were a team of Japanese working between about 1989 and 1992. It is technically difficult because unlike photons or neutral molecules, electrons are of course charged!)

(Tomomura, Endo, Matsuda, Kawasaki and Ezawa.)

Here’s an excellent, non-technical overview of such work that’s been done since Ingram Taylor’s work:

https://community.emc...­


More recently, similar behavior has been seen using molecules containing as many as 400 atoms.

Physicists have also shown that individual particles create an interference pattern that builds up as they pass through the slits one by one and then arrive at a detector. This confirms that each individual particle does indeed behave like a wave as it passes through the slits. Observing this behaviour in large molecules is particularly interesting because it allows researchers to investigate whether there is a threshold at which particles stop behaving like waves and begin to obey the classical laws of physics.

It’s highly unlikely that there is any such cut-off point. As far as the decoherence interpretation of QM is concerned only QM is true, and the appearance of the “classical world” is just that: predictable according to the decoherence effect!

Of course, those of us – everyone I’m guessing! – who would like to get their hands on the definitive interpretation of QM would very much like there to be an real quantum-classical watershed. This would add extra factors into consideration and presumably also alter the mathematical structure of QM itself, which would be quite a theoretical challenge! .. But it would have the consequence of providing useful constraints on what any interpretation of QM is not “allowed” to say, thus putting teastable flesh for the first time on interpretative bones!

Readers unfamiliar with the line of research alluded to within Paul’s notification will be pleased to know that the first person to achieve such a single-particle-at-once effect with any “particle” was the British mathematical physicist Geoffrey Ingram Taylor who using very dark-filter high optical quality glass was able to show that his own Young’s 2-slit interferometer was admitting only 1 photon at a time!

.. And it was low-budget – not like these Austrian geezers”

Thanks for this very interesting research achievement notification Paul. I have many times within mails sent to this Meetup Group mentioned the sterling work in support of the decoherence interpretation of QM which has been underway for nearly 20 years or so by a succession of teams led by the redoubtable Anton Zeilinger, and as I suspected a Wikiwebwhack on his name shows that the Markus Arndt mentioned in this article has indeed been working as Zeilinger’s understudy. Well trained that physicist!/color]

In 1999, Zeilinger abandoned atom optics for experiments with very complex and massive macro-molecules - fullerenes. The successful demonstration of quantum interference for and molecules (fullerenes) in 1999 opened up a very active field of research. Key results include the most precise quantitative study to date of decoherence by thermal radiation and by atomic collisions and the first quantum interference of complex biological macro-molecules. This work is continued by Markus Arndt.

(Not only fullerenes but fullerenes with wings on. Specifically, fullerenes with pentafluorophenyl groups attached. Molecular weights of 1,000 or more!)

A former member
Post #: 92
Hi,


Trying to get my head round this.

I do remember first learning about the Young's Slits experiment at school: and I also remember that as soon as we understood the significance of the result we demanded from our teachers an explanation of how this result merged into the real world where such things clearly don't happen. Precocious teenagers, lol.

I recall most clearly of all how angry the teachers became that we should dare to ask such an impertinent question. They put the whole class in detention and changed the subject very rapidly. My parents had to explain that the teachers were simply too insecure, and lacked the curiosity or intelligence to address any issue where they did not already know the answer; and were simply punishing the students in self defense. A much harder lesson, lol.

Anyway Paul has (thank you) re-asked the question, and so now I'm trying to understand the answer.

Ian provides a technical QM answer - "Quantum decoherence", but I feel that merely causes the question to be re-asked using new terminology. I'm reading this:
http://en.wikipedia.o...­
but I have the horrible feeling that when I understand it I may have a technical answer, bur still be no closer to any mental model of what is really going on.

Ian mentions a "quantum-classical watershed", and clearly we are interested in whether any such phenomena exists. However, I can distinguish two watersheds - the quantitative one and the conceptual one; and my hunch is that we will find no quantitative watershed, but that the conceptual watershed is inescapable.

Let me explain:


Quantitative: as the size of particles used in the Young's Slits experiment are progressively increased from a photon to a ping-pong ball I'd expect the QM interference pattern to fade, progressively and smoothly, into the uniform (or at least random) distribution predicted by Classical Physics. I would expect no watershed, no sudden discontinuity of behaviour. I think it would be truly astounding (though correspondingly informative) if we found one particle which exhibited the QM interference pattern in the Young's Slit Experiment, but another particle (1 % bigger, say) that exhibited the behaviour predicted by Classical Physics.

I do have a technical question on this point though. Does using larger particles degrade the experiment by forcing you to used wider slits for particles sufficiently large to exhibit Classical behaviour? What happens if you conduct the experiment using typical small particles but the larger slit size? Is the apparent paradox caused by this series of experiments using progressively larger particles, simply an illusion because the experiment won't work with wider slits. I have no idea. Anyone?


Conceptual: The interference pattern has a line of zero probability. Not small, zero. The waveform exactly cancels itself out. As we move to successively larger particles this zero line either persists or it does not. Maybe I'm wrong, and the zero line only really exists if the slits have zero width (this is, I think, another way of looking at my technical question above); but if that is not the case, then the zero line exists for some particles, so it must either be present or be absent for any given particle (no gradations in the concept of zero) and a conceptual watershed exists.


The final possibility is that I'm hopelessly confused, because I'm deluding myself by thinking I can employ this sort of macro-level logic to QM. That's a real possibility. So I end where I started i.e.

"Trying to get my head round this."


But also with a plea for someone who understands more than me to come and explain... and I do mean understand, not simply know the science, lol.


Thoughts?

Ideas?




Thanks



Peter


lan B.
user 10895495
London, GB
Post #: 152

From Peter:

>I do remember first learning about the Young's Slits experiment at school: and I also remember that as soon as we understood the significance of the result we demanded from our teachers an explanation of how this result merged into the real world where such things clearly don't happen. Precocious teenagers, lol.

You were more sophisticated than me then. I recall coming across this in late-first year A-level Physics, and I just went into denial. The question gnawed at me during my undergraduate years but I continued to ignore it until the mid-'90s. Shameful! (On the other hand, the patient explanation of my physics teacher -- also the Head of Physics -- indicates that my teachers were perhaps a little more sophisticated than yours, so .. swings and roundabouts.)

After playing around with different possibilities -- having plunged myself into a 6-month-long, hairshirt monastic regime of trying to get to grips with what the official QM textbooks bought or ordered via then-Dillons, Gower Street, then-excellently crammed basement Physics Section -- and not the popular science books -- were really saying -- I finally decided to take the de Broglie relation: [lambda] = h/mv (one of the simpler equations to crop up in A-level physics!) seriously, at phenomenological face-value. It was clearly a fundamemtal, if very bizarre, feature of the world.


> My parents had to explain that the teachers were simply too insecure, and lacked the curiosity or intelligence to address any issue where they did not already know the answer; and were simply punishing the students in self defense. A much harder lesson, lol.

One is strikingly reminded of the behaviour of plainclothes police when they've been "rumbled", and one then proceeds for obvious reasons to take the p... out of them. They tend actually to get quite violent -- I have personally experienced this -- and especially so when one converts the situation into a game and takes them out for deliberately time-wasting "surveillance walkies" on the London Underground system. Particualrly touching are the occasions in which several hours into some amusing but otherwise totally pointless excursion one then re-encounters someone seen earlier, and sometimes wearing different clothes! It's utterly hilarious when one points this fact out and consequent, intense, denial-behaviour ensues. Try it sometime!

Maybe I shouldn't have typed this. It's undeniably off-subject and must strike those who've never had such experiences as unbelievably bizarre.

(Still, this is a forum set up to discuss the extremely bizarre nature of quantum mechanics, which is almost as bizarre as that of the Metropolitan Police, and perhaps the take-home lesson in Social Psychology is that stupid people tend to compensate for their inadequacies by seeking positions of power rather than of intellectual discrimination, and so it becomes rather easy to propose a Unified Theory which accounts for the class of experiences of which Peter's and mine are members.)


>I do have a technical question on this point though. Does using larger particles degrade the experiment by forcing you to used wider slits for particles sufficiently large to exhibit Classical behaviour? What happens if you conduct the experiment using typical small particles but the larger slit size? Is the apparent paradox caused by this series of experiments using progressively larger particles, simply an illusion because the experiment won't work with wider slits. I have no idea. Anyone

If over-wide slits are used, the interference pattern washes out gradually as more and more photons enter each slit and as the ratio of their wavelength to the slit-width continually falls the phenomenon underpinning this -- diffraction -- begins to lose its teeth. Maximum effectiveness is achieved whenever the slit-width is [lambda]/2. Even in Zeilinger's experiments, technology is pushed to the absolute limits by trying to fabricate uniform-diameter and same-diameter slits of around, say, 40 nm-width, and this is why such specifically double-slit experiments weren't successfully carried out until the early 2000s rather than the 1930s when "atomic-wave interference" was first observed, but this time by using highly oblique beam-incidence diffraction gratings instead!

40 nm is very wide even by biological macromolecule standards! Even the human haemoglobin molecule -- molecular weight around 68,000 if I remember right -- is < 10 nm in diameter, and that's getting on for 2 orders of magnitude > massive than the phthalocyanines and functional group-augmented buckyballs referenced within the current research literature.


>The interference pattern has a line of zero probability. Not small, zero. The waveform exactly cancels itself out. As we move to successively larger particles this zero line either persists or it does not. Maybe I'm wrong, and the zero line only really exists if the slits have zero width (this is, I think, another way of looking at my technical question above); but if that is not the case, then the zero line exists for some particles, so it must either be present or be absent for any given particle (no gradations in the concept of zero) and a conceptual watershed exists.

There is never any empirical "zero line" (if I understand your terminology correctly). Just as the interference maxima appear "speckled" rather than continuous, on closer inspection of the CCD pattern -- due to the discrete, quantised nature of photons as Uncle Albert pointed out in 1905 -- so one finds that even in the "deepest voids" of the parallel minima "anti-fringes" a lightly scattered, just-beginning-to-snow-like pattern of just a few photons -- or electrons, or buckyballs! -- is always found to be present.

It is of course the case that the use of successively more massive "quantum artillery"through double-slit interferometers does as said constitute a severe technical challenge. This is because of the de Broglie relation: mass is in the denominator, and so matters rapidly become extremely finicky. Also, the entire interior of the interferometer must for obvious reasons be pumped out unto a state of extremely hard vacuum. These "test-particles" are no longer photons!

Velocity is also in the denominator of de Broglie's neat little expression, and so the electrons and particularly the larger molecules in question must have a very low effective beam temperaure. Coupled to this consideration is the fact that as in consequence [lambda] tends to zero then the necessity as earlier alluded to of needing to engage effectively in diffracting-through-slits at all demands ever-smaller (both) slit widths and slit separations, which as said is very challenging from a technical point of view.

[ Continued .. ]











lan B.
user 10895495
London, GB
Post #: 153

[ Continued .. ]

Consider: in order to produce effective Zelinger-type results one needs to run the experiment:

1) As near to Absolute Zero as possible!

2) In as high-vacuum an environment as can be achieved.

3) Using minutely carved pieces of interference "filter" whose slit diameters are < less than 1,000th the separation of the shortest wavelengths which the human eye is able to discrimiante. I.e. invisibly small!

Hope all this helps.

Ian


A former member
Post #: 93
From Ian:
... Maybe I shouldn't have typed this. It's undeniably off-subject and must strike those who've never had such experiences as unbelievably bizarre.

(Still, this is a forum set up to discuss the extremely bizarre nature of quantum mechanics, which is almost as bizarre as that of the Metropolitan Police, and perhaps the take-home lesson in Social Psychology is that stupid people tend to compensate for their inadequacies by seeking positions of power rather than of intellectual discrimination, and so it becomes rather easy to propose a Unified Theory which accounts for the class of experiences of which Peter's and mine are members.)


But this is soooooo important: yes - you should have typed it. It represents the first point since I joined this group where any connection between Quantum Theory, Cosmology and Consciousness has emerged.

We now have the beginnings of a Unified Theory of Incompetence arising from the reconciliation between the Special Theory of Stupidity (in which the simple inability of an individual to apply logic causes random or uncertain behaviour in a manner analogous to QM uncertainty) and the General Theory of Corporate Madness (which shows how large groups of people come to share, and determine their actions by, totally bizarre ideas which they reject as soon as they are separated from the group in question). Examples of the latter include most religions, Sony's "Corporate Culture" which led to the staggering belief that it was morally entitled to install viruses (the Sony rootkit) in every PC on the planet in defense of it's digit media rights, and the genuine Nanny State worldview exhibited by all bureaucrats that they really do know better than the individual (including themselves) what is best for each individual.

So if anybody thinks they can take this and put some flesh on it, please start a new thread. As a "left brained corporate professional" (thanks Frances) I lack, by definition, the wit, imagination or empathy to even conceive of such a theory, far less develop it, so I must stand aside for others to bring this to fruition.


But I'm looking forward to the peer review when the fully fledged theory is submitted prior to formal publication.


Enjoy... BUT no responses to this idea WITHIN this thread please - start a new thread if we want to develop this.


Peter
A former member
Post #: 94
From Peter:
>I do have a technical question on this point though. Does using larger particles degrade the experiment by forcing you to used wider slits for particles sufficiently large to exhibit Classical behaviour? What happens if you conduct the experiment using typical small particles but the larger slit size? Is the apparent paradox caused by this series of experiments using progressively larger particles, simply an illusion because the experiment won't work with wider slits. I have no idea. Anyone

Ian:
>If over-wide slits are used, the interference pattern washes out gradually as more and more photons enter each slit and as the ratio of their wavelength to the slit-width continually falls the phenomenon underpinning this -- diffraction -- begins to lose its teeth. Maximum effectiveness is achieved whenever the slit-width is [lambda]/2. Even in Zeilinger's experiments, technology is pushed to the absolute limits by trying to fabricate uniform-diameter and same-diameter slits of around, say, 40 nm-width, and this is why such specifically double-slit experiments weren't successfully carried out until the early 2000s rather than the 1930s when "atomic-wave interference" was first observed, but this time by using highly oblique beam-incidence diffraction gratings instead!

40 nm is very wide even by biological macromolecule standards! Even the human haemoglobin molecule -- molecular weight around 68,000 if I remember right -- is < 10 nm in diameter, and that's getting on for 2 orders of magnitude > massive than the phthalocyanines and functional group-augmented buckyballs referenced within the current research literature.


>The interference pattern has a line of zero probability. Not small, zero. The waveform exactly cancels itself out. As we move to successively larger particles this zero line either persists or it does not. Maybe I'm wrong, and the zero line only really exists if the slits have zero width (this is, I think, another way of looking at my technical question above); but if that is not the case, then the zero line exists for some particles, so it must either be present or be absent for any given particle (no gradations in the concept of zero) and a conceptual watershed exists.

There is never any empirical "zero line" (if I understand your terminology correctly). (Ed: You do) Just as the interference maxima appear "speckled" rather than continuous, on closer inspection of the CCD pattern -- due to the discrete, quantised nature of photons as Uncle Albert pointed out in 1905 -- so one finds that even in the "deepest voids" of the parallel minima "anti-fringes" a lightly scattered, just-beginning-to-snow-like pattern of just a few photons -- or electrons, or buckyballs! -- is always found to be present.

Thank You.

I think you are telling me that using wider slits to allow larger particles to pass through them will cause the interference pattern to wash out, but is not sufficient on it own to explain the slow melding of the QM interference pattern into the uniform Classical Physics phenomena as particle size increases.

Shame. I had such a lovely experiment in mind. First, use slits of zero width to eliminate all tolerance issues and problems with failed diffraction. Such slits require no effort to manufacture perfectly. You may wonder, of course, whether slits with zero width are in fact different from no slits at all: and it is indeed easy to prove that the difference is null. However, you may recall that in the first Consciousness thread I proved the trivial result that the difference between Strong and Weak AI was null: but carefully abstained from moving from this to the highly contentions assertion that the two are the same thing. I shall adopt the same cautious sophistry here.

So, how do the particles pass through these zero width slits? That's easy - Quantum Tunneling. The hard bit is how the particles know where the slits are. They need to do their tunneling in the right place. Zero width slits may prove rather hard to detect. I have concluded that the experimenter must focus his mind on the slits and guide the particles so that they can find the slits and tunnel through the (apparently) solid material the slits are embedded in at the right point.

Essentially, the experimenter is guiding the particles with his mind.

This gives a whole new meaning to the term "thought experiment".

I accept, of course that this experiment contains the embedded assertion that the particles have enough awareness to accept the experimenter's guidance and "know" where the slits are. I think this implies the particles are conscious. I concede this may prove a mildly contentious assertion - hence the importance of conducting this experiment.



Enjoy.


Again... if this is worthy of ANY response a new thread is called for, I think.




Peter
A former member
Post #: 95
I had to explain Young's Slits to a schoolkid in Armenia yesterday, and found this video:

http://www.attano.com...­


Enjoy



Peter

A former member
Post #: 96
Hi,

Returning from the remote astral planes, where my penultimate and ante-penultimate posts reside, to reality...

Oops! reality? we are talking about QM effects here, lol

returning to what passes for reality in a Universe which includes Quantum Theory, I find I am still having trouble getting my head round all this.

Ian has suggested Quantum Decoherence as the explanation for the Quantum phenomena meld into the Classical phenomena we all experience in everyday life.

I'm prepared to be corrected, but as I read up on Quantum Decoherence it does not feel right. I don't buy it, it won't wash, and hence in particular it cannot cause the washing out of the quantum interference pattern Ian describes.

So why don't I buy it. Well... Quantum Decoherence involves the loss of synchronization between different particles. The Young's Slit experiment demonstrates each particle interacting only with itself. Decoherence should not affect that.

So, what other possible explanations might there be?

I turn, as always in my hour of need, to the Sacred Elephant. I know he exists because I have written a poem about him; and he is very wise.

He is walking through the jungle and he encounters a tree. He must pass around it. Which side should he take? This is a rather large scale version of the Young's Slit experiment (Yes Ian, I can confirm that the Sacred Elephant is (significantly) more than 40 nm wide).

Clearly, if anybody is watching the Sacred Elephant the waveform must collapse and we will get the normal everyday Classical Physics behaviour. The Sacred Elephant will make a decision, he will pass one side of the tree or the other, and everything will be "normal".

But what if there is no observer? Might the Sacred Elephant interact with himself and create an interference pattern?

The degradation caused by having large slits would be significant, but we have agreed that is not a complete description of the transition from QM to Classical Physics.

So I would be forced to conclude that in the absence of any observer, the Sacred Elephant would interact with itself and create a (degraded) interference pattern.

However, the Sacred Elephant is quite intelligent, and almost certainly conscious:
. "And he lives Alone in the Jungle Wild"
. "Where he sits in State and preserves the Lore"
so he may act as a permanent self observer, forcing his waveform into a state or permanent collapse, and thereby ensuring he exhibits only Classical Behaviour.

Looking at smaller particles, but still relatively large by QM standards, it is clear that you could still get interference patterns so long as the particle is not observed. However, as the particles get larger the issue of ensuring they do not get observed may become critical, and I think it would do so very quickly.

I think this might prove to be an explanation of how QM merges into Classical Physics. Moreover, if this is the explanation, we would expect to see a very rapid transition from QM behaviour to Classical Physics behaviour as the particle size reached the point where it cannot avoid being observed. Conversely, if the explanation is something different (such as Quantum Decoherence) we'd expect, well.. I would anyway, a much smoother transition.

So this idea does make a testable prediction, it is real science, notwithstanding the involvement of the Sacred Elephant.



Peter





A former member
Post #: 99
We do not have a consensus explanation of quantum physics because we cannot do any experiments (and may never be able to) to see what if anything lies hidden beneath the quantum world. The decoherence explanation is just one idea of many, though I think it has quite a following. My understanding of this idea is that all matter and energy is in a state of quantum superposition (as in 'two places at the same time' for example) all the time. We tend to picture this concept in terms of 'fuzziness' but really state superposition is much more subtle and much harder to understand than that simplified picture. It applies to position, energy, spin and other observables. It can involve quantum entanglement where two or more far-apart particles behave as if they were a single entity.

In the decoherence explanation all that happens when you measure the position of a 'fuzzy' electron is that you force the fuzzy electron into communication with measuring apparatus and cause it to be a lot less fuzzy and show itself to be in one place. Its degree of fuzziness has been greatly reduced but (perhaps) not completely eliminated.

In contrast, other explanations (or interpretations) of quantum physics make a strong distinction between (a) the superposed state of the electron, the progress of which over time is governed by Schrodinger's equation (or its relativistic version), and (b) the single state of the electron being in one definite place immediately after measurement. Then all these other quantum interpretations have the huge problem of explaining how and why the Schrodinger equation suddenly stops applying to that electron bit of the universe in question.

So the decoherence interpretation simply denies that Schrodinger's equation suddenly stops applying. That's a great plus. But it's a sort of pragmatic answer that does not really satisfy those like me who would love to know what's really going on in the two-slit experiment. And some of the other quantum interpretations do offer answers.

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