Jump to content
Objectivism Online Forum
TerribleTractors

The Double-Slit Experiment

Rate this topic

Recommended Posts

My friend showed me this video and it is very puzzling (and interesting). According to this experiment, electrons act differently when being observed than when they are not being observed, yet in order for the electron to process the information that it is being observed, the information would have to have traveled at four times the speed of light (impossible) for it to be present in the eventual action of the electron. The video is cartoonish, but explains it well:

http://www.highexistence.com/this-will-mindfuck-you-the-double-slit-experiment/

Edited by brian0918

Share this post


Link to post
Share on other sites

Please use the search function to find similar topics that have already been discussed (e.g. 1, 2).

The simple answer is that to observe an electron requires that you first shoot a photon at it. That photon interacts with the electron, changing the result.

I highly recommend watching Richard Feynman's lecture on Quantum Mechanics here. It takes all the magic out of QM.

And as an added lesson: don't learn your science from popular media. The animated video shows you a false reality (electrons moving as individual particles, or switching back and forth between particles and waves), and then reasons from that false reality.

Edited by brian0918

Share this post


Link to post
Share on other sites

what do you think of this (this is by Mills of BlackLight Power, from preface from his book):

----------------------------------

...

Many paradoxes and internal inconsistencies arise in quantum mechanics such as the requirement that two or more

contradictory results exist simultaneously, the existence of infinities, non locality, and violation of causality, to mention a few.

Unlike the solutions learned in the freshman year, none of the solutions are unique—algorithms to remove infinities and to add

fantastical corrections are totally discretionary [1 14]. One exception is the one electron atom, but the Schrödinger equation is

not a directly experimentally testable relationship. Rather, it is postulated. The solutions make no physical sense. Electron spin

is missed completely. And, in many cases, the solutions contradict experimental observations [1 14].

To add to this confusion, Newton’s Laws of mechanics are presented as invalid. With the assumption of Galilean

transformations, they fail to remain invariant at high speed. Special relativity is introduced as an independent mechanics theory

based on the constant maximum of the speed of light, which was demonstrated by the Michelson Morley experiment. But, this

experiment addressed light propagation and not mechanics, except for disproving the ether and a universal reference frame in the

sense of the speed of light. Maxwell’s equations, which govern light propagation, remain since they are consistent with special

relativity and predict c based on universal properties of spacetime. No connection to mass or mechanics is given despite the

result of the equivalence of mass and electromagnetic energy from special relativity. There is no connection to particle masses

and atomic theory. And, the infinite sea of virtual particles of atomic theory is paradoxically an ether which was abandoned with

special relativity.

Furthermore, it is taught that the validity of Maxwell’s equations is restricted only to the macro scale and that they do not

apply to the atomic scale. This is inconsistent with the application of special relativity to the mechanics of atomic particles at

high speed and the radiation of accelerating atomic particles wherein, paradoxically, Maxwell’s equations give the

electromagnetic wave equation that governs the emitted radiation. Yet, when the particle motion is thought of as a current,

Maxwell’s equations predict the radiation of atomic particles as well. Then, contradictory, postulated quantum mechanical rules

apply to the radiation or stability of electrons in atoms, which should be treated electrodynamically. Neither a special relativistic

or Maxwellian approach to the radiation is deemed to apply even though the Maxwellian Coulomb potential and special

relativistic corrections to the electron mass are invoked. Even more disconcerting is that supposedly special relativity is the basis

of electron spin in the Dirac equation. But, the solution requires an infinite sea of virtual particles that is equivalent to the ether.

This constitutes a glaring internal inconsistency because the absence of both an ether and an absolute frame is the basis of special

relativity in the first place. In addition, considering the simplest atom, hydrogen, no physical mechanism for the existence of

discrete radiative energy levels or the stability of the n ? 1 state exists—only circular reasoning between the empirical data and a

postulated wave equation with an infinite number of solutions that was parameterized to match the Rydberg lines [1 14].

Furthermore, the elimination of absolute frame by special relativity results in the elimination of inertial mass and

Newton’s Second law, foundations of mechanics, and gives rise to the twin paradox and an infinite number of energy inventories

of the universe based on the completely arbitrary definition of the observer’s frame of reference. Newton’s Law of gravitation is

also to be unlearned. It is replaced by a postulated tensor relationship that only applies to massive gravitating objects. The

replacement theory is explained in terms of warping of spacetime without any connection to the physical laws learned as a

freshman or any connection to atoms that make up the massive gravitating bodies. General relativity predicts singularities and a

deceleration cosmology—the opposite of that which is observed [15 16]. It is to be accepted with quantum mechanics as the

correct atomic theory even though these theories are mutually incompatible. It is further disconcerting that the Uncertainty

Principle of quantum mechanics—one of its fundamental tenets—predicts a continuum of particle masses and gives no

mechanism for the existence of atomic particles of precise inertial and gravitational mass in the first place. And, the infinite sea

of virtual particles and vacuum energy fluctuations throughout the entire universe requires an infinite cosmological constant that

is obviously not observed.

...

----------------------------------

Share this post


Link to post
Share on other sites

what do you think of this (this is by Mills of BlackLight Power, from preface from his book):

----------------------------------

These complaints are not original to Mills. Some are valid and some are not. Everyone acknowledges that relativity theory and quantum theory do not conjoin neatly to produce a quantum gravity theory. Almost no one will grant that the quantum virtual particles are equivalent to the absolute reference frame version of the aether theory.

Share this post


Link to post
Share on other sites

First, what is an explanation in exact sciences, in particular in physics? "Within advanced science and as far as logic is concerned, *explanation* is deduction within a theory" (M.Bunge)

Do not count as explanations all kind of analogies and such.

Specifically, for the double slit experiments with electrons, the explanation should consist in solving the corresponding Schrödinger equation.

It seems that only numerical solutions are possible and I have seen several publications about this, and they do indeed obtain an interference-like pattern. The slits are modeled by boundary conditions for the partial differential equation (which the Schrödinger eq. is)

For a graphical representation of the (complex) solution of the Schrödinger equation for the double slit see http://www.kfunigraz...es/104_18a.html

This site (http://www.kfunigraz.ac.at/imawww/vqm/) contains a lot of other such representation, for various cases. Highly interesting and very instructive!! The site is based on two books by Berndt TALLER, "Visual Quantum Mechanics" and "Advanced Visual Quantum Mechanics".

It is also often claimed that the *transitions* between different quantum states are non-physical, that they cannot be described by the Schrödinger equation. This is false.

This site "Pictures of the Hydrogen Atom" http://www.physikdid...llung_2_uk.html shows, among others, the process of transition of a hydrogen atom between states with various states described by (n, l, m) - electron energy, orbital momentum and one of its projections, respectively. The link is this:

http://www.physikdid...spielANIM3D.htm

Alex

Edited by AlexL

Share this post


Link to post
Share on other sites

There is only one correct theory -- the theory of reality. Explanation means explaining what is really going on. You assume shrodinger equation is correct way to explain what is going on, but in fact quantum physics doesn't have solid experimental evidence. It interprets the cat paradox as that there are two cats, one dead, and one alive. That is absurd, as far as my understanding is. It takes a comfortable position that it can't be disproved, by definition, and that is a circular argument.

Share this post


Link to post
Share on other sites

quantum physics doesn't have solid experimental evidence. It interprets the cat paradox as that there are two cats, one dead, and one alive. That is absurd,

The math of quantum mechanics is very good at agreeing with the experimental evidence, but the interpretations of the theory have been debated. What you just described is the Copenhagen interpretation which is not popular among actual physicists now.

Share this post


Link to post
Share on other sites
"Within advanced science and as far as logic is concerned, *explanation* is deduction within a theory"

There is only one correct theory -- the theory of reality. Explanation means explaining what is really going on.

OK, let's take a simple example - free fall.

How do you explain that the velocity is proportional to the time, and the displacement - to t2 ?

So, what is really going on here? Why precisely this time dependency? And, BTW, what do the words "velocity" and "displacement" mean?

Sasha

Edited by AlexL

Share this post


Link to post
Share on other sites

There is only one correct theory -- the theory of reality. Explanation means explaining what is really going on. You assume shrodinger equation is correct way to explain what is going on, but in fact quantum physics doesn't have solid experimental evidence.

It has an enormous amount of solid experimental evidence. Your computer, phone, dvd player and all other modern electronic gadgets can only exist thanks to tha application of quantum mechanics.

It interprets the cat paradox as that there are two cats, one dead, and one alive. That is absurd, as far as my understanding is. It takes a comfortable position that it can't be disproved, by definition, and that is a circular argument.

Nope. The famous Schrödinger cat paradox was a thought experiment by Schrödinger in the early years of quantum theory to describe the difficulty of the transition from QM in the microscopic domain to classical physics in the macroscopic domain. It was at the time not clear why the superposition of quantum states in the atomic realm disappeared for large objects (like cats), it seemed that only the fact of observation by a conscious observer destroyed the superposition, which gave rise to weird speculations about the importance of observing by a consciousness. However, this problem has already been solved long ago. The observer is not necessary, it is the phenomenon of decoherence, due to the interaction of the quantum system with the environment, that explains that there can be no superposition of an alive and a dead cat. The cat is dead or alive long before anyone looks into the box, just as classical physics predicts. Experiments have shown that superposition of states can exist for relatively large molecules like fullerenes, but these are still far from macroscopic objects, for which any superposition decoheres in extremely short times. It seems however that many popular accounts of QM are still decades behind the facts.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×