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Irresponsible Journalism in Scientific American | alQpr

A recent article in Scientific American promotes the views of someone who “has spent his entire career championing and extending de Broglie’s views” and “recently spoke to Scientific American about his lonely(!) path and why de Broglie might have been on to something” without any specific acknowledgement that the vast majority of physicists are well aware of this “pilot wave” theory and do not believe that there is any significant chance that it “might explain what’s wrong with quantum mechanics“.

Source: Irresponsible Journalism in Scientific American | alQpr

Silly Sock Version of EPR

A common way to start talking about the EPR “paradox” is with the parable of Bertelman’s socks.

One is green and the other red, and sadly for poor Bertelman, they have been separated and shipped to opposite ends of the universe in boxes to be opened by Alice and Bob.

No-one is surprised to hear that when Alice opens her box and sees a green sock then she knows immediately that Bob’s box contains a red sock.  We all know that she could have been informed ahead of time about Bertelman’s sartorial oddity, and of course the socks both started out together. So no-one thinks that Alice’s ability to predict what Bob will see indicates some mysterious ability to instantaneously “turn his sock red”.

So there must be something more to the EPR issue than just knowing that if a pair is split into two boxes and if we find one in one box, then the other must be in the other box.

And indeed there is. The quantum problem is not with the values of one property but how those of different properties can be related. Bertelman’s boring socks were just too simple.

But Dr. Fahni’s funny socks socks are another matter. They are actually iridescent!

Depending on how they are illuminated, one is red and one green or one yellow and one blue.

When either Alice or Bob sees one as red then with the same lighting arrangement the other sees a green one and vice versa. And the same goes for yellow and Blue. And also for Orange and Turquoise. (Oh! I forgot to mention that. There is an intermediate lighting setting under which we see orange and turquoise. And there, as we shall see later, is the rub!)

If Alice sees red, then in the same light Bob sees green (and vice versa), but if he looks in the Yellow-Blue light he sees either with equal probability.

And if Alice sees yellow then in the same light Bob sees blue (and vice versa), but if he looks in the Red-Green light he sees either with equal probability.

In fact we can get this randomness just by starting with a drawer full of pairs of socks in which each left sock is any one of RY,GY,RB,GB (with RY meaning that in Red-Green lighting it shows Red and in Yellow-Blue it shows Yellow) and the corresponding right sock is its opposite (ie GB,RB,GY,RY respectively). Now if a pair is drawn at random and sent to Alice and Bob, then if Alice sees Green she knows that in the Red-Green light Bob will see Red but she has no idea what he will see in the Yellow-Blue light. So it may be getting a little bit complicated to arrange, but there’s still no great mystery in either the randomness or the correlation.

But now let’s look at what happens when the Orange-Turquoise measurement is compared to the other two. 

One possible set-up is to build a bigger sock drawer with pairs in which the left sock is of type  RYT,GYT,RBT,GBT,RYO,GYO,RBO,GBO and the right always opposite (ie respectively GBO,RBO,GYO,RYO,GBT,RBT,GYT,RYT). If there are equal numbers of each type of pair then when Alice sees Red she still knows that if he looks in RGlight Bob will see Green but if he looks in YBlight he will see either Yellow or Blue with equal probability and if he looks in OTlight he will see Orange or Turquoise with equal probability (and similarly for all the other combinations).

BUT, since Orange is “closer” to Red and Yellow than to Green and Blue, and Turquoise is closer to Green and Blue than to Red and Yellow, Dr. Fahni wants to maintain the opposition by ensuring that whenever Alice sees Red, Bob is actually less likely to see Orange than Turquoise.

In fact when Alice sees Red, if Bob uses OTlight he sees Turquoise just 15% of the time and Orange 85%, and when she sees Green those figures are reversed. Also, if Alice looks in OTlight and sees Orange, then if Bob uses RGlight he will see Red 85% of the time and Green just 15%, and if he uses YBlight he will see Yellow 85% and Blue 15%.

So let’s see how Dr Fahni might have filled up his sock drawer to make this happen. The obvious strategy would be to have unequal numbers of the different pair types with RYT and GBO being least likely, RYO and GBT most likely, and the others somewhere in between.

A first try might be to have just GBT or RYO on the left sock (each matched with the other on the right sock) but this won’t work because we still want GY and GB to be equally likely (and add up to the total proportion green results in RGlight). And similarly for RY and RB.

So in fact we need  GY=GB=RY=RB=25%. 

But Bell noted that RB=RBT+RBO<=RBT+RBO+RYT+GBO=RBT+RYT+RBO+GBO=RT+BO

So if the situation is symmetric with RT and BO equal, they cannot be less than 12.5%

But with GYT+GBT=85%of50%=RYO+RBO and RYT+RBT=15%of50%=GYO+GBO, we get RT=BO=7.5%.

So the observed correlations cannot be achieved by just selecting at random from a set of pre-prepared pairs of socks.

What About the Ice Cores?

Once again a Quoran tries to ask a “gotcha” question about the fact that geologically recent ice cores show CO2 lagging temperature over the last few glaciation periods.

One key point is that it is NOT true that temperature rises always precede the rise in CO2. As noted by Richard Rothwell (6years ago!) “If the trigger event is an increase in CO2 due to a massive increase in volcanic activity, then CO2 will rise first and the temperature rise will follow.” And as pointed out by Elijah Williams (3years ago) a good example of this is the Permian Extinction event when “Massive volcanic emissions increased CO2 from around 400ppm to over 2000 (maybe even over 6000) ppm over the course of 75 thousand years. This caused rapid increases in temperature, ocean hypoxia and acidification, and very nearly did render Earth uninhabitable. ‘The Great Dying’ wiped out over 80% of all genera and is the greatest extinction event we know of.”

Another example of CO2 increase preceding temperature rise is happening right now. We can see that CO2 has been going up more and more rapidly for a couple of centuries, but it is only within the last 50 years or so that the consequent increase in temperature has become undeniably measurable (even though any competent physicist could have told you it was bound to follow – at least since Arrhenius did an approximate calculation in 1896).

But as the ice cores show, it can also go the other way because A causes B does not necessarily mean that B does not cause A.

Of course, when B does also cause A we get what is called positive feedback and the risk of testing how far that might go by playing FAFO with the CO2 vs Temperature situation is somewhat more serious than a burned out amplifier in your sound system.

Source: (1002) Alan Cooper’s answer to What real hard evidence do we have that CO2 is actually driving the increase in temperature? We know from ice core samples that initial temperature rises always preceded the rise in CO2 by several centuries. Correlation is not causation. – Quora

Bump on Lake

The surface of water in a lake is NOT always perfectly level in the sense of being geometrically flat. It is just “level” in the sense of not having any transverse gravitational field, and follows the curvature of a gravitational equipotential which at the Earth’s surface bends downwards about eight inches per mile.

This is obvious if you ever look across a large lake towards a distant city with tall buildings, but is also possible to notice when swimming in a much smaller lake with your eyes just an inch or two above the surface.

Source: (1002) Alan Cooper’s answer to If the Earth isn’t flat, how come the surface of water in a lake is always perfectly level? Since when does water have the ability to curve and stay curved? – Quora

Mass-Energy Equivalence

The “mass” of any complex “body” or system of interacting component “bodies”, defined as its resistance to acceleration from rest, includes not just the masses of its components but also terms corresponding to the kinetic energy of their motions relative to one another and to the force fields acting between them.

The numerical factor relating the amount of energy corresponding to a unit of mass depends on the units of time and distance but it is exactly one if we use years for time and light-years for space or approximately one if we use feet for distance and nanoseconds for time. In terms of more normal units like metres and seconds the conversion factor is very large and one unit of mass corresponds to almost 17 powers of ten (ie 100,000,000,000,000,000 ) in units of energy.

Source: (1002) Alan Cooper’s answer to Can you give an intuitive description of what Einstein’s mass-energy equivalence equation means in one or two short sentences without describing the equation or the math? – Quora

Absolute Rest?

It is a common misunderstanding that what someone once jokingly called the “Big Bang” theory describes the universe as expanding from a single point.

What General Relativity actually suggests is just that in the distant past the universe was very dense (but still of infinite extent) and very hot, with everything flying apart so that since then it has been becoming less dense but not actually “expanding” in the sense of having a boundary that is moving outwards.

With regard to the second question about whether an object can “remain stationary”, in the absence of gravity (ie in Special Relativity) there is no way for an observer to identify whether or not it is moving in any absolute sense. But it is possible to identify whether an object is moving relative to any particular other object, or to the centre of mass of all the other material in its visible universe (so long as that visible universe contains just a finite total mass). And in General Relativity this can be done by checking for isotropy (sameness in all directions) of the microwave background radiation coming from the “Big Bang”.

Source: (1002) Alan Cooper’s answer to What is the rate of expansion of the universe from a single point? Can an object remain stationary in the universe? – Quora

Does Observing Change a Wave to a Particle?

The electron cloud is just a way of predicting what the observer will see on future observations of the electron. When an observation is made, the range of what might be possibly seen in future observations is reduced. So starting right from the moment an observation is made, the observer’s knowledge about the electron is described by a new wave which applies until the observer makes another observation. But the apparent wave behaviour does not cease. It just changes to that new wave, and the electron is never seen to behave like a classical particle. In fact, it is not actually ever either a classical particle with a definite position or a wave of some definite form, and the question of what it “is” may not have any real meaning. All we can talk about are the probabilities of various observations – which we know from experiments do not correspond to any classical picture of what is going on.

Source: (1001) Alan Cooper’s answer to What is it about the act of observing that changes an electron cloud into a single electron that behaves like a particle? – Quora

Do quantum fields have mass?

As so often happens, the answer to this question depends on what you mean by the words used.

Quantum fields are not things in the universe, but rather postulated quantities that are used in an attempt to provide descriptions of possible states of that universe. A state of the universe described in terms of such fields may or may not have mass, depending on the situation and on what you mean by “mass”.

And “mass” is also problematic. The parameter called “mass” in the equations defining a quantum field theory is related to the mass of a minimal (“single particle”) excitation of that field – and indeed this can sometimes be zero (as in the case of the Electromagnetic field for example). But a single photon does have energy and Viktor Toth tells us that Einstein said “E=mc^2” and so it must have mass. So what gives?

Well, when Einstein said “E=mc^2” (or perhaps a bit after the first time he said it) he understood that this was just in the particular situation of a system in its rest frame and a single photon does not have a rest frame!

For states involving many photons it may be possible to define a specific frame of reference by requiring some condition of balance between the observed frequencies (eg for two photons, the point from which they both appear to be departing in opposite directions with equal frequencies might perhaps be taken as the centre of mass). And in that case the force required to accelerate the entire system away from rest might be used to define a rest mass of the system that includes the kinetic energies of its components (in this case just the energies of the photons) as well as the masses of those components (which in the case of photons would be zero).

Source: (1001) Alan Cooper’s answer to Do quantum fields have mass? – Quora

Seeing the Curve

When swimming you can notice the effect over the width of a small lake:

But if you want to see a noticeable effect over just two meters then it depends on what you mean by “noticeable” (eg it would be a trivial high school exercise to calculate the largest radius at which a two meter tangent line ends at least one mm from the corresponding arc).

Source: (1001) Alan Cooper’s answer to How close to the Earth’s core would you need to be to see an ‘uneven’ water level?Not regarding temperature etc making it impossible, how deep would you have to dig to see a noticeable curvature in, lets say a 2m length of water? – Quora

Mass “Loss” in Chemical Reactions

In exothermic chemical reactions the combined masses of the resulting molecules is indeed slightly less than that of the inputs. But this does not make “the system’s mass appear to decrease” for two reasons. The superficial reason is that in chemical reactions the mass decrease due to energy loss from the system is far too small for us to detect, and so we did originally learn the very slightly wrong conclusion “that mass is conserved”. But the deeper reason is that, so long as the system is isolated (eg by including walls that reflect or absorb photons so that none can escape), then the system’s mass does not in fact decrease at all. This is because the system’s mass includes not just the masses of the individual molecules but also all of the energy in the system (including both photons and the thermal kinetic energy of relative motion of molecules). And if we do allow energy to escape, then the system’s mass is not conserved, as what we have learned more recently (though well over a hundred years ago now) is that what is conserved is not just the total mass of constituent particles but rather the total energy (where that includes a contribution from the masses of any particles within the system).

Source: (1001) Alan Cooper’s answer to In chemical reactions like CH₄ + 2O₂ → CO₂ + 2H₂O, we learn that mass is conserved.But since heat energy is released, E=mc² implies a tiny mass decrease. Heat is emitted as massless photons, so why does the system’s mass appear to decrease? – Quora