Can the wave function of an electron be divided and trapped (article)

Hi,

No they don't break up. Electrons have NEVER been observed to spilt into, say two, and trigger two counters at once. To do so would prove QM false, as a fundamental postulate of QM is that any measurement must result in a single Eigen value.

The "Wave function" is not physically real. |psy> has a one to one correspondence to the *probability* P(x) of, say an electron being within a certain range, not "x", the position itself.

split its wave function like this, considering that electric charge

Pop, layman accounts of QM physics invariable talk nonsense.

The wave function is not the particle, i.e. the shape of the wave function has absolutely nothing to do with the shape of what it describes. Period.

Kevin Aylward

Did you read the article? I think Jamie is misinterpreting what's being said, but they're getting results that are not consistent with whole electrons either traveling through liquid helium or not -- rather, they're getting results that are consistent with some percentage of an electron traveling through liquid helium, then turning into a whole electron (or, presumably, not) at the bottom of a container.

So, not quite what Jamie is describing, but certainly wacky enough to be consistent with a lot of other QM phenomena.

No, not "smaller size things".

Wave functions are not "things" with sizes, exactly.

Um, no.

Electrons have been "split", but not in the way you think:

(They also mention that the "parts" detected come in a specific set of si zes which sounds like yet another unsuspected quantization effect. I'd like to see the experiment reproduced in other media frinst LN2 to see if it ha ppens, and if the quantization changes. I bet it does.)

So part of a given electron wave function injected into a vessel of liqui d helium makes it to the bottom. What I want to know is, what would a simil ar detector mounted above the liquid surface (coincidence-connected to the bottom one), positioned to see the *reflected* parts, see?

If it sees the "rest" of the partial electron that made it to the bottom, does that constitute "which-way information"?

Mark L. Fergerson

Yes.

I don't see that as being a valid interpretation of the results.

The basic issue with QM "explanations" is that there isn't any. There are the postulates of QM, and what they predict as experimental results. It all gets down to waffle when anyone tries to "explain" a result in some sort of classical description for the layman. The fact that a probability distribution may "split up" is completely irrelevant to where a particle may or may not physically be, if it is anywhere at all prior to measurement.

The root cause of all the confusion is simply not accepting that classical thinking is wrong. If it were so, QM would not be needed. Period. QM represents something fundamentally unexplainable by any macro level pictures. It is new information not derivable by any previous knowledge. Physical objects just don't behave in an "explainable" way.

According to the article, they can churn the QM mathematics and predict the results. That's all that matters.

When consciousness gets mentioned, I start rolling my eyes....

Kevin Aylward

Yes Feynman said something about this, about the limits of explanation.

quantization effect. I'd like to see the experiment reproduced in other media frinst LN2 to see if it happens, and if the quantization

changes. I bet it does.)

Hi,

They did mention that there appeared to be a continuous range of sizes of the bubbles:

"it appears there aren't just 18 objects, but an effectively infinite number of them, with a "continuous distribution of sizes" up to the size of the normal electron bubble."

I think this is evidence of the physical reality of the Schrodinger wave equation, and that it is not simply a mathematical construct.

This is a related page about the reflection/transmission of quantum particles through a barrier:

what would a similar detector mounted above the liquid surface (coincidence-connected to the bottom one), positioned to see the

Ya that would be a good experiment I think, it sounds a lot like the experiments of "entangled" light, I guess the uncertainty will be mainly in the reflected energy, as the bubble seems to be able to be measured quite accurately.

cheers, Jamie

Hi,

How do you explain this statement from the article if the wave function is not physically real:

"The idea that part of the wave function is reflected at a barrier is standard quantum mechanics, Cooper said. "I don't think anyone would argue with that," he said. "The non-standard part is that the piece of the wave function that goes through can have a physical effect by influencing the size of the bubble. That is what is radically new here.""

Already one of the researchers has a Nobel prize, I think there should be another one rewarded now as it seems like the illogical idea that the wave function is only mathematical might be disproven.

cheers, Jamie

Oh ya and that statement is from "Nobel laureate and Brown physicist Leon Cooper"!

cheers, Jamie

The wave function does not have a physical effect. It does not cause anything. The wave function simply measures the probability of an observable. The wave function is the *result* of some physical arrangement, not a cause.

Unlikely. There are alleged proofs that a measurement of the wave function is impossible.

section 6.3

"If [the wave function were a characteristic of a single particle] it would be of interest to perform such a measurement on a single particle (say an electron) which would allow us to determine its own individual wave function. No such measurement is possible" Blokhintsev, D. I., The Philosophy of Quantum Mechanics, Reidel, Dordrecht, Holland, 1968 . "

Kevin Aylward

I should add.

Standard Quantum Mechanics dictates that there is only *one* wave function for a multi-particle system. For example the wave function of a molecule has a De Broglie wavelength characteristic dictated by the total momentum lambda = h/mv . A molecule does not diffract with some sort of wavelength associated with what would be the wave functions of the individual particles of the molecule. This pretty much demolishes the view that a particle's function is physically real.

There are some approximate methods of solving the Schrodinger by effectively making an expansion on the assumption of a product of individual wave functions, e.g. Hartree?Fock

Kevin Aylward

Hi,

I think the way you are looking at the particle wave function is incorrect as you are assuming there is a particle and then trying to find the wave function, but really if you believe the Schrodinger equation, there is no particle but instead only the wave function, and that is physical reality (which we often simplistically describe somewhat incorrectly as particles)

cheers, Jamie

Oh...

Err... ahmmmm....

I would suggest that you do a first course in graduate QM.

Hint:

The Schrodinger equation is

H|psi> = E|psi>

Where H is the Hamiltonian operator of the system. For a one particle system the Hamiltonian is Del^2 (P) + PE where P is the momentum of the particle. The psi wave function is calculated from actually knowing the particles momentum, to wit QM explicitly relies on objects having characteristics expressed by their momentum and energy observables.

The wave function is simply an intermediate mathematical function with which to calculate, for example, the expectation (average) of an operator (observable), e.g.

Quantum field theory takes a mathematical approach of particles being "excitations" in a field, but whether or not this has an relevance to what a particle may or may not be in the real universe, is open to debate.

Kevin Aylward

Hi,

I am just saying that the Schrodinger equation is a wave equation, and to interpret that into a probability distribution of particles is where the problems and paradoxes of Quantum mechanics seem to arise, but for all practical purposes it is necessary to define the particles, but in reality they are an incomplete and simplified version of reality, since apparently the Schrodinger equation may be used to describe the whole universe's quantum wave state:

atomic, and subatomic systems, but also macroscopic systems, possibly even the whole universe."

This has nothing to do with particles, yet it could describe the whole universe from an outside perspective if that equation was known.

The particles come about from our own perspective/interpretation.

Yes an excitation in a field, and the field specifically being the physical quantum wave field.

All open to interpretation and opinions, just my two cents!

cheers, Jamie

This opens up a can of worms. The idea that a photon was a disturbance in a real physical medium/aether was rejected after the Michael/Morley experiment and led to the Special Theory of Relativity. If there is a field, it actually has implications on the validity of SR.

Kevin Aylward