/ Quantum Leaps are Actually Gradual

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Shani 10 Jun 2019

Really interesting: https://t.co/vfydmkqSQW?amp=1

Pursued by a bear 10 Jun 2019
In reply to Shani:

Off the top of my head, isn't a quantum leap the smallest measurable bit of change; so it's an occasion where the popular meaning and the scientific meaning are opposites?  Similarly, but not scientific, the word 'cleave' has two meanings which are in direct opposition and I think the entymology of the word 'nice' shows that it started meaning the opposite of how we use it today.

I should probably have checked before saying that, but now I can look forward to being corrected multiple times . . .

T.

john arran 10 Jun 2019
In reply to Shani:

I now can't get out of my head the idea of a cat in a box dying a slow and painful death.

Shani 10 Jun 2019
In reply to john arran:

I'm again struggling with Zeno's paradox of the arrow!

Martin W 10 Jun 2019
In reply to Shani:

What a good article.  Just shows that public service science journalism doesn't have to dumb things down to the point of meaninglessness.

Thanks for posting the link.

wercat 10 Jun 2019
In reply to Shani:

Well it would be nice to find "hidden rules" rather than true randomness at the heart of it all.  I'm with Schroedinger and Einstein on that, not that either of them had shoelaces I'd be worthy to tie.

wintertree 10 Jun 2019
In reply to wercat:

> Well it would be nice to find "hidden rules" rather than true randomness at the heart of it all.  I'm with Schroedinger and Einstein on that, not that either of them had shoelaces I'd be worthy to tie.

If you haven’t come across Yves Couder and his oil drop experiments, you might enjoy reading about them and watching some videos.  Thought provoking macroscopic experiments.  Perhaps pilot wave theory isn’t the write of its often been proclaimed.  Of course, the classical field and particle set a pilot wave quantum world is built on is itself probably made from turtles.

If I was a betting type, I’d put money on everything being an illusion of thermodynamic information.

kestrelspl 10 Jun 2019
In reply to Pursued by a bear:

An important bit of subtlety here. In quantum mechanics systems are often described as being in a "superposition" of states. What this means is that if a system can have two states |x> and |y> (the funny vertical line angle bracket notation means a state), which are for example |x> the cat being dead and |y> the cat being alive there's some non-zero probability that the system is in state |x> and a non-zero probability the system is in state |y>. Mathematically we write this as |system>=a|x>+b|y> so a and b are related to the probabilities.

In quantum transitions in atoms you usually have systems that have a very high probability of being in one state, that then some time later transition to another state i.e. at time=0, the system is in state |system>=|x>, then some time later it's in |system>=|y>

What the article is saying isn't that the two states |x> and |y> blur into one another and you can catch the system somewhere between the two, but that the probabilities a and b don't suddenly jump from being 100% to 0% when a physical system transitions from state |x> to |y>. i.e. there's a gradual flip as a decreases and b increases

kestrelspl 10 Jun 2019
In reply to wercat:

https://en.wikipedia.org/wiki/Bell%27s_theorem is an interesting read re-hidden variables

kestrelspl 10 Jun 2019
In reply to wintertree:

The difficulty with pilot wave theory and the many other interpretations is that until they provide observables that will be different from other interpretations it's just philosophy.

I'm personally an advocate of the SUAC interpretation (Shut Up And Calculate), some stunning results so far. Electron electric dipole moment measured and agreeing with theory to 28 parts per trillion!

wintertree 10 Jun 2019
In reply to kestrelspl:

> The difficulty with pilot wave theory and the many other interpretations is that until they provide observables that will be different from other interpretations it's just philosophy.

I agree entirely - I get quite miffed when various profs start banging on about a particular interpretation as if it’s evidenced as fact.

Thst doesn’t stop Couder’s experiments from interesting me - for a long time many rather naive people insisted pilot wave theory was never realisable so it’s nice to see quantum style behaviour emerge from a set of coupled classical systems and a bit of noise.

> I'm personally an advocate of the SUAC interpretation (Shut Up And Calculate), some stunning results so far. Electron electric dipole moment measured and agreeing with theory to 28 parts per trillion!

Impressive but not really an interpretation so much as a validation.  Well, unless one thinks the universe is nothing but computation and information...   The quest for interpretation is really a sidetrack I think from the quest to understand the basis.

Deadeye 10 Jun 2019
In reply to Pursued by a bear:

> Off the top of my head, isn't a quantum leap the smallest measurable bit of change; so it's an occasion where the popular meaning and the scientific meaning are opposites?  Similarly, but not scientific, the word 'cleave' has two meanings which are in direct opposition and I think the entymology of the word 'nice' shows that it started meaning the opposite of how we use it today.

> I should probably have checked before saying that, but now I can look forward to being corrected multiple times . . .

> T.

You mean etymology. Unless "nice" has a particular meaning within the study of insects!

Pursued by a bear 10 Jun 2019
In reply to Deadeye:

Just so. My mind was obviously still on the beetle I'd recently evicted from the living room.

T.

mbh 10 Jun 2019
In reply to wintertree/kestrelpl:

What can we reason from this from H'sUP? If delta t goes up, so delta E goes down, so ....so what?

kestrelspl 11 Jun 2019
In reply to mbh:

Yeah, I may have missed something as it's a bit out of my area (particle physics), but to me this seems like a seriously impressive feat of accurate measurement rather than something that changes our interpretation of Quantum Mechanics. It's always been the case that the amplitudes associated to states can change continuously according to the dynamics of the system (e.g. Schrodingers equation).

kestrelspl 11 Jun 2019
In reply to wintertree:

Yes, I was being a bit tongue in cheek. Basically as long as the theory as posed continues to produce testable experimental predictions we'll keep testing them. When someone comes up with something that provides different predictions we'll test that too and then we can get a proper answer. I realise of course that for that to happen we need to fund people to think about what different interpretations there are, and whether they have testable predictions. However, I reserve the right to be personally more interested once there is a prediction.

DubyaJamesDubya 11 Jun 2019
In reply to Pursued by a bear:

> Off the top of my head, isn't a quantum leap the smallest measurable bit of change; so it's an occasion where the popular meaning and the scientific meaning are opposites?  Similarly, but not scientific, the word 'cleave' has two meanings which are in direct opposition and I think the entymology of the word 'nice' shows that it started meaning the opposite of how we use it today.

> I should probably have checked before saying that, but now I can look forward to being corrected multiple times . . .

> T.

I always understood it to mean a step from one level to the next with no intermediate position being possible. The size of the jump/leap is not the issue.

Robert Durran 11 Jun 2019
In reply to DubyaJamesDubya:

> I always understood it to mean a step from one level to the next with no intermediate position being possible. The size of the jump/leap is not the issue.

I agree. I've never thought the popular meaning had to be a big jump. I remember once having a bit of an argument over whether the routeQuantum Jump (E5 6b) was appropriately named since it involves a big dynamic move - I thought it was fine since it is a transition between two stable positions, whereas my friend thought it inappropriate because he thought quantum jumps had to be small.

Post edited at 10:55
HansStuttgart 11 Jun 2019
In reply to kestrelspl:

> I'm personally an advocate of the SUAC interpretation (Shut Up And Calculate), some stunning results so far. Electron electric dipole moment measured and agreeing with theory to 28 parts per trillion!

I'll stick to Shut Up And Measure then 

Blue Straggler 11 Jun 2019
In reply to Shani:

But what does Ziggy say?


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