Quantum Physics Questions

[jim_griff]

Hi everyone. I've been off this form for a while but decided to rejoin as my interest in electronics has suddenly reappeared again! I have a couple of questions that have been playing on my mind for a few months. Not sure if anyone is an expert in physics and/or could point me in the right direction in my research. The two questions are related and are as follows:

1. Magnetic field cancellation in balanced pair of wires: If I have two wires with opposing electric/magnetic fields and they cause field cancellation due to opposing current flow, where does the magnetic energy disappear to? Can this cancellation effect be used to increase the ability to transfer more energy through power transmission lines by using a balanced setup to prevent losses due to EM radiation?

2. Light wave cancellation via thin-film interference (see link below): If light waves are cancelled out at specific frequencies when a thin oxide layer exists on a piece of metal, where does the energy in those specific frequencies go? For instance, if I have an oxide layer on a piece of metal that causes cancellation at 532nm and I shine a 532nm green laser pointer at the metal, will the light just cancel out and disappear into nothingness? Where does the energy of the 532nm wave go if it cannot be seen or detected?

https://en.wikipedia.org/wiki/Thin-film_interference

As a sound engineer with lots of experience in adding/subtracting waveforms and the effects it produces, I know that if I cancel one wave with another that is out of phase, no sound will exist on the output. I understand that, electrically speaking, the energy is maintained within the system and is lost as heat in the components. The electricity has to go somewhere and will generally hit resistance and be converted to IR radiation. But what about light waves cancelling out? What about magnetic fields too? Where does the "lost" energy go? I can't find any information about this specific effect or the loss of energy (if any occurs in the first place!) Sorry if it's a dumb question!

EDIT: Also, a little off the topic... If I am to saturate the gravitational field (putting so much mass in one place), it produces a black hole. What would happen if I am to saturate the electric field or magnetic field with some form of hyper-capacitor or hyper-inductor? Of course they don't exist, but I'm curious what the effects would be. Although, these questions probably can't be answered!

[Brumby]

My understanding in the first two questions is that the energy does not 'disappear'.  If you have two 'waves' than are 180º out of phase, both continue to propagate independently and it is only when they are 'observed' that their sum is  found to be zero.

I propose that at the point of observation, each individual wave would be absorbed and the energy transferred into heat.


No research in the above - just what seems logical to me.....  which means if there is a quantum mechanics twist, I will have got it all wrong.

[Brumby]

As an example of what I mean, consider the instantaneous wave cancellations that occur in interference patterns.  Move your measurement plane and the result changes in a manner consistent with there having been NO cancellations at any point in the path of the waves.

[helius]

A black hole is not a "saturation" of the gravitational field; if a black hole is sufficiently large, you would not notice anything at all when you pass over its event horizon. The gravitational field continues to increase further in towards the center, called the singularity, without any kind of limit.

[edy]

I'll give these questions a shot, but I'm not a physicist. I did study some chemistry, thermodynamics and physics in University so I'll use my intuition and logic see how far it takes me (I know, with Quantum physics, classical intuition falls apart). 

1. Regarding the 2-wires in parallel with opposite currents, they do not completely cancel. You have to think of the field in 3-dimensional space. If you take a cross-section of the system, the fields combine to form a more complex oval shape. No matter how close you get the wires to each other, there will still be a slight delta between your distance to each wire, therefore the field strength contribution will differ from each wire and therefore you will still have some field. As far as where the energy goes, I think it would go to mutually interfering with the electron flows in each wire. You have one wire imposing it's electromagnetic field on the other wire which is trying to conduct electrons through it in the opposite direction to the first... charges trying to pass through an externally-applied field. The other wire does the same to the first. So there will be some kind of interaction where the currents I am guessing will reduce or greater voltage will be needed to keep driving the circuit.

2. As far as light wave cancellation, the way this works is that you have light bouncing off two layers of the thin-film and they happen to meet again they are exactly 180-degrees out of phase with each other so they "cancel out". You can imagine if you point a laser of the same frequency the thin-film is designed to cancel at the film it will suck all the light out! But light is also composed of photons, and here we have again an issue with wave-particle duality and the way light behaves when it passes through the double-slit experiment. It makes no sense that there should be an interference pattern if you slow down light to the point of having only one photo pass at a time.

So now imagine you have a thin-film and you shoot ONE PHOTON at a time at it. It either bounces off the first layer, or it bounces off the second layer. Since it can only bounce off one layer at a time (like the double-slit experiment) then you would think you would not be able to get an interference (how can it interfere with nothing)? So shooting one photon at a time at the thin-film you should expect to see ALL your laser light that interacted with each layer bounce back. No intereference. Right? So with thin-film you need to imagine in the QUANTUM world your light has to do all possibilities at the same time, with certain probabilities. And the wave-function of these probabilities is what you are adding and subtracting. So the light doesn't JUST bounce off one layer, or the other. It also may refract a bit as it's going through, some may bounce several times off the thin-film and then escape, and so on. Light paths will be many different lengths and the probabilities of all the possible paths and refractive and reflective interactions, no matter how improbable, will need to be taken into account.

Obviously, if you are shooting photons at something, it will absorb some of the energy... not all will bounce back. Even a really good mirror. Some will interact with the atoms in the thin-film. A thin-film will have to reflect certain photos off the top layer, and some off the bottom, but there are also atoms in between the 2 layers of the film. The only reason light reflects off those 2 layers preferentially is because it is a junction between 2 different materials with different refractive indices. Like a soap bubble... you have air outside, then a thin layer of soap, then water, then another thin layer of soap, and then air inside the bubble itself. The light bounces off the soap/air or soap/water layers, but there are many interactions along the way inside. So the assumption that a laser of 532nm will disappear when shooting it at an oxide layer that has a separation that exactly will cancel a 532nm wavelength must be false to begin with.

3. Regarding a gravitational field, I don't think you can really consider that it "saturates" space when there is a black hole. Saturation just doesn't seem to be the right word to use. Saturation to me is more like when you have a sponge with holes in it and all the space in the sponge gets taken up by something... so you've saturated the sponge and it can't hold any more. Space, on the other hand, can hold an infinite amount of mass which then causes a singularity and therefore infinite gravitation field at that point. At least that's what I think when I hear about black holes. All our known physics and quantum ideas break down at that singularity because we can't deal with infinities and we don't know what the heck is really going on.

Also, gravity is always attractive. Electromagnetic forces can be both attractive and repulsive. It has polarity. So you can imagine a gravitational "sink" where it just sucks in everything. But I can't imagine an electromagnetic "sink" unless you somehow obtained a huge number of similar-charged particles... like protons and stuck them together and made them collapse into a singularity. Now imagine trying to pack that many protons together... the amount of repulsion they will have for each other... Electromagnetic force is MANY MANY times stronger than gravity.

Imagine you are on the space station and you have 2 magnets separated by 1 foot...they will quickly float to each other and stick. Now image the same size and weight blocks of lead with no magnetic charge and see how long it takes them to float to each other, being drawn only by their mutual gravitation forces to each other. It will take a very long time indeed! So we know gravity is VERY VERY VERY Weak in relation to Electromagnetism. So in order to create a "hyper-cap" or "hyper-inductor" you need to keep in mind that you are trying to pack a huge number of the same charged particles into a tiny space and there is only so much you can pack together before the entire thing blows apart. At what point can you SQUEEZE protons together so that their gravitational forces overcome their repulsive electromagnetic forces and end up with a massive "proton-like" singularity, or a "mono-pole" in space? And could such a thing even truly exist or would it instantly explode?

Anyways, these are interesting questions and quite fun to make the brain work through a "Gedankenexperiment", as Eintein would say. Thanks for getting my gears turning.   

[Brumby]

Can this cancellation effect be used to increase the ability to transfer more energy through power transmission lines by using a balanced setup to prevent losses due to EM radiation?

So... no.

[Brumby]

As for the gravity question - I'm not sure there is a 'saturation' level - but I have absolutely no means to back this up, other than referring to the 'Big Bang' when all matter was contained within a really, really small space.

[jim_griff]

My understanding in the first two questions is that the energy does not 'disappear'.  If you have two 'waves' than are 180º out of phase, both continue to propagate independently and it is only when they are 'observed' that their sum is  found to be zero.

I propose that at the point of observation, each individual wave would be absorbed and the energy transferred into heat.


No research in the above - just what seems logical to me.....  which means if there is a quantum mechanics twist, I will have got it all wrong.

I can see your point of view and it is the one I've had for a long time. The trouble is that if the energy is transferred into heat, it would have to be absorbed as one wavelength and then re-emitted as IR radiation.

I understand the first point that you make that the propagation of each wavefunction continues and do not disappear completely. But then again, "where" do they go?

[jim_griff]

A black hole is not a "saturation" of the gravitational field; if a black hole is sufficiently large, you would not notice anything at all when you pass over its event horizon. The gravitational field continues to increase further in towards the center, called the singularity, without any kind of limit.

What I mean by a "saturation" of the gravitational field is that it creates a high enough field to create "black hole". So, a saturation of the gravitational field creates a black hole, but what would a "saturation" of the electric or magnetic field create? A black electric/magnetic hole?

[helius]

The analogy is too vague... when you pack charges very close together, they tend to explode. That's what happens in particle accelerators: charged particles are brought together very close (by using high momentum) and then explode in a shower of daughter particles. The repulsive force between same charges means you need a lot of energy, like that, to bring them into a close spacing.
This doesn't happen with neutral particles (like atoms, or ordinary matter): the repulsive forces are too weak, although they resist the compression, the inward gravitational force is so high it overcomes them.
What happens in a neutron star is interesting: the atoms of a depleted star, with too little energy to keep its shape, fall inward together and are compressed to a very dense core. It becomes so dense that gravity overpowers the electric field repulsion between nuclei. As the nuclei are pressed together, the strong interactions that stabilize protons and neutrons are disrupted, and the protons decay into neutrons (emitting e+). So the electric field dissipates as charge gets tossed out of the growing pit of neutronium. The electric field never had a chance to become as intense as the gravitational field became.
You can also look at fusion reactors, which need to bring charged nuclei together under very strong fields. That requires a lot of power input, and if it isn't sufficient the plasma explodes and prevents fusion occurring. Electric fields can never become very dense without external power.

[edy]

What I mean by a "saturation" of the gravitational field is that it creates a high enough field to create "black hole". So, a saturation of the gravitational field creates a black hole, but what would a "saturation" of the electric or magnetic field create? A black electric/magnetic hole?

Gravity is purely an attractive force. Electromagnetic forces have 2 types of charges/poles and therefore attraction and repulsive forces between like and opposite types. To create an electromagnetic "black hole" you would need to squeeze a bunch of electrons together, or a bunch of protons together (which by the way are made up of 3 quarks which have fractional charges that are both + and - anyways that just happen to add up to +1). The point is, you would need to create a massive "monopole" out of some elementary particle of whatever charge you decide to use (either + or -) and keep that ball of charge together, which is not going to happen because every particle wants to repel the other and fly apart. You cannot turn that ball of charge to some kind of "collapsed" state which will keep it together, because the repulsiveness of the charges is always orders of magnitude greater than the gravitational attraction between the particles as you continue to SQUEEZE is down.

Now what is interesting is that in a black hole you have all types of matter falling in, both + and - charges. Electrons are -, but then protons and neutrons are composed of quarks which have fractional charges that just happen to add up to +1 and 0. So somehow you CAN squeeze these particles together ever more closely because they are next to other particles of opposite charge that they want to stick to, even though a simliar-charged particle is there as well.

I mean, just look at the inside of a proton and a neutron. Protons are 2 UP quarks (+2/3 x 2) and 1 DOWN (-1/3 x 1). So when you add up +2/3 x 2 = +4/3 - 1/3 = +3/3 = +1, which is the charge of a proton. The neutron is 2 DOWN (-1/3 x 2) and 1 UP (+2/3) so when you add up -2/3 + 2/3 = 0, the charge of a neutron. Yet these particles stick together very nicely.... You can have 2 UP quarks (which are +2/3 charge each) having absolutely no problem as long as a DOWN quark is there between them, and yet it is only -1/3 charge as compared to the +4/3 of the UP quarks. But the proton doesn't fly apart!!!! It can happily exist as a particle, quarks stable inside.

Anyways, when a black hole forms, everything goes in. The electrons, the protons, the neutrons, all of it has to fall in. So ultimately you get some neutral entity. Or is it? What if you had a black hole and decided to only "feed it" protons? Somehow you were able to send electrons in another direction in the universe and only gave it protons. Would the black hole be "charged"? Could you somehow feel that on the outside? By definition, a black hole can't emit information of any kind. It is lost forever. Although some theorize that the information becomes encoded on the event horizon. Either way, if you feed one proton at a time into a black hole, do you make it positively charged? 

One other thought that is more philosophical is to think of the universe as trying to revert back to it's original state of the bing bang singularity. The concept of charge, anti-particles, and all of the various particles and opposites of those particles are a perturbation of the fabric of space/time that has separated matter/energy, along different dimensions that ultimately when all brought back together add up to a ZERO SUM GAME. Our understanding is still evolving and we really don't know why but there is a search for an elegant theory and mathematics that would provide that esthetic of it all adding to NOTHING. Balance. Ying and a Yang. That would at least help explain more of it. If we "Big Banged" out in this direction, could another anti-universe "Big Banged" in the opposite direction? Will we all collapse back into a big crunch, or go on forever? And what is this "Dark Energy" that is supposedly make us expand ever so fast (or is that an illusion that curves on itself at some point). 

[helius]

Black holes are not required to be electrically neutral. The equations are consistent with charged black holes (they are charged because the matter that fell into them was charged). This is not part of the information that is "lost", because the charge can be detected from outside the event horizon (as can angular momentum). It would be hard to observe such charge at astronomical distances.

[T3sl4co1l]

1. Yes. Sort of.  They're called transmission lines.  The fields are supported by the two conductors, contained between them.  Ideally, the fields do not extend to infinity, and therefore there is no radiation.  Twisted pair (except at frequencies harmonic with the twist) and coax are good examples.  (Twin lead has an overall dipole moment, so has some radiation at a distance.)

2. Reflected.  An interference filter is a spacial implementation of a transmission line filter, where waves bounce off mismatched lines.  Rejected waves are reflected (in or out of phase, depending on frequency), or transmitted (usually with weird phase shifts, particularly around the band cutoff edges, except for minimum-group-delay (Bessel) filters).

Filters with absorption are much more common.  Pigments and semiconductors and such.  (Semiconductors act like a lowpass filter, where the bandgap energy corresponds to the cutoff frequency.)

You can make electronic filters with absorption too (constant resistance filter).

Tim

[TimFox]

General statement about constructive and destructive interference:
Interference neither creates nor destroys energy, but re-distributes it spatially.
With two parallel closely-spaced wires, there will be a relatively large field between the two wires.

[jim_griff]

Thanks very much for all the replies There's a lot there to think about and research

I'm very appreciative of the time you have all spent replying to my post. I can't really add anything as I am not as knowledgable about Physics. But thank you all so much anyway!