/sci/ - Science & Math

That's no electromagnetism, that's Chess.

Seriously, what the?

>>4765616

>What is the "nature" of an electromagnetic field?

What do you mean by "nature"? eXPLAIN YOURSELF!

>How is the force it exerts in some particle transmitted through space?

Photons

>I've read that "photons" are .....random bullshit

You read wrong, or misunderstood what they wrote.

>How is the force it exerts in some particle transmitted through space?

Charge carriers. Also all particles have an angular momentum that manifest as magnetic moments. Spintronics.

>What is the "nature" of an electromagnetic field?

The nature of an electromagnetic field is to organize matter into configurations consistent with the laws of nature.

>>4765622

Sorry, wrong image, but still, the questions are these. I'm actually a med student really interested in physics, but almost no time to learn anything more than the basics in calculus, and undergrad physics.

>>4765623

By "nature" I meant "what is an electromagnetic field made of".

>>4765626

>Also all particles have an angular momentum that manifest as magnetic moments. Spintronics.

Ok, I think I've got it partially. So a charged particle, by means of its oscillating electric field produces a magnetic field, right? And the magnetic field itself is the means through which the force is applied, correct?


>>4765623

>Photons

So the light we see is the carrier of the force exerted in a particle due to the electromagnetic field of another particle?

>>4765628
Charge doesn't propagate very far through space. However, energy, photons, do and those packets of energy can influence the magnetism of a system by adding more energy to it.

When you want to create more electricity from a dynamo you increase the kinetic energy driving the dynamo. Photonic energy can 'turn' electrons faster. Not literally but that is the best visualization I can think of under the circumstances.

>>4765638
>electromagnetic field

An electromagnetic field is nothing more than a series of number's we assign to space. It has patterns so we can work with it and describe it. Don't think about electromagnetic fields. Think about photons, in the particle state, traveling through space to hit electrons and raise their energy states. Much easier to think about photons as particles in this instance rather than electromagnetic waves.

>>4765638
>what is an electromagnetic field made of

Photons and other charges particles

> the light we see is the carrier of the force exerted in a particle due to the electromagnetic field of another particle

That sentence is kinda worded funny, but I think I understand what you meant. Yes, the answer is yes.

>>4765628
np.

Just make sure to put "pic unrelated" in your post so we know for next time.

>>4765616
Field is some way (a function) to assign some number (or a vector) to every point in space. Charged objects move according to how this field changes in space.

The force is given by how the field changes, i.e., imagine a ball on some wrinkled surface, it would fall down the slope. With electromagnetic field the rules are somewhat different, but similar -- the so called Lorenz force.

After many experiments and deep thinking it turns out that, if we want to be very precise, electromagnetic field can be looked at as if it was made of infinitely many oscillators (Jeans' theorem). The quantization (the photons) is then given by quantization of these oscillators (quantization of an oscillator can be shown in quantum physics).
The photon isn't a disturbance in field. It's a quantum of the field itself. The force acting between charged bodies then can be explained by exchanging photons, but the physics of this is _not simple_ and cannot be explained in bunch of posts.

>>4765657
*Lorentz force

damn, I always mix these two up

>>4765646

Ok, I think I'm starting to get the point.

SO, "light" as we perceive it daily is actually a manifestation of the the energy being transmitted from a source to our retina.
And thus, "light", or photons, are considered literally "packets", or quanta, of energy being transmitted through space.

Though photons are packets they can also behave like waves, correct? So the "electromagnetic waves" really *do* exist? I mean, can you visualize the onscillations of that wave (not the same way as we see light, but the way we draw it, like the graph of sin(x))...

This way, if we could photograph a photon, what we would see something like the pic?

>>4765616
There is one field called the "electromagnetic field". It is basically just a lot of photons interacting with each other and other charged particles, carrying away energy, and sometimes charge.

We often see the electromagnetic field in two different states, the electric field and the magnetic field. In reality they are the exact same field. The magnetic field is just an illusion of the electric field caused by special relativity (the very fast motion of charged particles).

Whenever you have objects moving fast you get a distortion in space-time, this is special relativity. The magnetic field is just the distorted version of the electric field.

In fact everything about the magnetic field can be found from applying the principles of special relativity to the electric field.

Any other questions?

>>4765660
The wave/particle duality is kinda fun to think about. Consider this:

A photon travels 30,000 light years across the cosmos and a human being staring up at the night sky receives that photon into their retina and they 'see' a star. What happens to the photon? In the exchange of photons between particles the photon just bounces back and forth ( or is absorbed and re-emitted ). When that photon from a distant star hits your retina it ends its journey for all time. It is gone. No one else will ever 'see' that same photon you saw for the rest of existence.

Now ask yourself what happens you, personally, are trying to observe an experiment about the vary photons that you are removing from existence by observing them? What happens? How can you perform an experiment in which you must observe the photons but in doing so you remove them from existence?

>>4765660
>So the "electromagnetic waves" really *do* exist?

Waves can exist in an "electromagnetic field". Photons are not these waves though. Photons are better regarded as particles.

>>4765657
I think this is one of the best posts on 4chan ever

>>4765654

Thanks, I'll remember that!

>>4765651

Oh, I see, so the electromagnetic field is not be thought of as a huge sheet of fibers that give support to particles, but rather they are abstractions of some mathematical functions (the gradient operator and stuff) to describe phenomena we can measure, right?

---To be honest, it's hard to think of something in a way I'm not used to. But I get the point, I think.

>>4765653

That's cool, so light is a force carrier. In a practical example:

THe axons of neurons are sometimes surrounded by fat tissue (myelinated) at somewhat regular intervals. In these fibers the action potential is faster, meaning that the ion transport from outside the cell to its inwards is faster and they kind "jump" the places where there is myelin, which is an insulator. The movement of the ions, or charged particles, produces a magnetic field that exerts a force in other surrounding ions. This force is carried over by means of photons, meaning that we "produce" light, even if it's a very small amount of it. Is this assumption correct or am I completely mistaken?

>>4765677
In this sense you have NEVER seen the same thing as someone else. Ever. If someone says 'Yea I saw that too' then they are wrong. No one ever sees the same photons as you. It is impossible. Every single microsecond that you are alive you spend seeing something 100% completely unique.

>>4765677
That's not particle/wave duality but problem of measurement.

>>4765659
the lorenz force is the force young greylag geese have towards rubber boots.

>>4765693
I remember I cracked up when I learned what Clausius-Mossotti equation for index of refraction is called

http://en.wikipedia.org/wiki/Lorentz%E2%80%93Lorenz_equation

>>4765686
Right. Photons hit receptors in your eye that initiate those electrotonic potentials. Are wondering how those electrotonic potentials can propagate down a neuron just using the principals of magnetism and ionic gradients inside and outside the cell, without anything seemingly "doing the work"? The work, in the Newtonian sense, is being done by electromagnetic fields that are created by the movement of like forces repelling each other.

If you take a magnet and move it towards a like charged magnet it will repel. The repulsion does work. The work will be equivalent to the force you used to move the magnets together. The brain works the same way but instead of a person moving those magnets together it is photons that do it and initiate that cascade of work.

>>4765689
>>4765677
>implying photons are unique

Nope
Photons with the same energy (spin, ect) are fucking indistinguishable. There is no "unique" when it comes to particle physics bro. Everything is literally an exact copy of everything else.

Stop trying to get all philosophical dipshit!

The photon that I see from an exploding star is exactly the same as the photon you see. There is no way WHATSOFUCKINGEVER to distinguish between fundamental particles with the same quantum states.

If we both watch a viral video, we are indeed watching the same thing. It doesn't fucking matter that we watched different copies.

>>4765686
>THe axons of neurons are sometimes surrounded by fat tissue (myelinated) at somewhat regular intervals. In these fibers the action potential is faster, meaning that the ion transport from outside the cell to its inwards is faster and they kind "jump" the places where there is myelin, which is an insulator. The movement of the ions, or charged particles, produces a magnetic field that exerts a force in other surrounding ions. This force is carried over by means of photons, meaning that we "produce" light, even if it's a very small amount of it. Is this assumption correct or am I completely mistaken?

Well, we clearly "produce" photons, as you say, because the force has to be carried by them, but they are virtual. Consider the simpler example of two electrons being repulsed (see pic): the photon exists only for a very short time to produce the necessary repulsive force, hence the term "virtual". It is a photon, but it's not part of radiation, and hence not "light" in the conventional sense. The same thing happens for magnetic forces (even though the situation is much more complicated because relativity).

>>4765705
You know, that's quite deep psychophysically and it confused the shit out of people who did statistical physics for some time.

>>4765707
>psychophysically

what the fuck did I write?

*philosophically

>>4765707
>mfw

There only exists one type of each particle. The "illusion" of the universe is due to the same ~15 particles bouncing back and forth through time. You can actually see all this shit with basic QFT and feynman diagrams.

The universe is just one really big feynman diagram made of ~15 particles endlessly interacting with eachother

>>4765715
I don't understand why are you angry. Indistinguishability of particles is no simple matter. It's much more profound than just "they are the same".

>>4765707
Of course it is. I mean, I can stomach subatomic particles being indistinguishable in practice, but in principle? What if I keep my eye on one of them and never lose it? I can't, of course, because particles aren't little dots, they're described by wavefunctions. But it makes a huge difference in statistical weight and ultimately in distributions

>>4765705
You might want to do some research on the problems we are having with Quantum computing and why they arise. That should clear up your misconception.

Photons and photonic systems are novel at any given point in time. Humans discovered this by examining black holes and how they correlate to information propagation throughout space.

No. We do not see the same photons. We see our own copy of photons that are generated from a 2D informational sub-space.

Time and space are relative because in order to travel faster than the speed of light you would have to travel faster than the particles shaping local reality as you observe it. In a manner of speaking, photons from a distant star don't exist until YOU observe them. Not Bob. Not James over at N.A.S.A. Until you personally observe those photons they simply don't exist as part of the matrix of your reality. Period.

>>4765715
Holographic Universe Theory disproves this.

The entire 3D universe is generated by information at a 2D level. ( Common sense when you think about black holes and the maximum informational density of anything in the Universe ). Those particles do not exist in 3D reality that we observe all the time. They pop up and pop out at a certain rate. An electron does not move through out space. It pops into our space for a small time then disappears back into the 2D quantum world then comes back based on that information...over and over and over and over and over for the past 13.7 billion years. It is likely that those particles that are pushed out into 3D space and then sucked back into 2D sub-space are completely novel.

>>4765720
>Indistinguishability of particles is no simple matter. It's much more profound than just "they are the same".

Nope. It is actually the simplest matter if you think about it. It makes perfect sense. What wouldn't make sense is if you could distinguish between identical things, it would be nonsensical by definition.

>>4765722
You cannot label indistinguishable particles. It doesn't work. If you could label them, they wouldn't be indistinguishable would they? LOL

>>4765741
A 1995 Camaro engine is an engine.
A 2002 Camaro engine is an engine.
A 2010 Camaro engine is an engine.

All these engines are exactly the same because they are all engines. Same displacement. Same fuel injection systems. They are EXACTLY THE SAME BECAUSE HUMANS AND THEIR WORDS ARE DEFINITE IN ALL CIRCUMSTANCES.

>>4765736
These particles are completely novel because they must obtain information about how to next appear in 3D space based on quantum information of other particles in that 2D sub-space we call the quantum world. This exchange of information is called entanglement. When those particles exchange information through entanglement in the quantum sub-space level then they become novel and manifest in 3D reality as such.

>>4765741
You obviously don't understand what are you talking about. Suppose you have two identical dices. Calculate the probability of sums of the two numbers you get for classical and quantum case. You get different numbers.

The statistics of identical particles is one of the most important and non-trivial consequences of quantum mechanics and it is not intuitive at all you ignorant twat.

>>4765727
It sounds like maybe you have taken high school physics, but nothing of any merit (College level).

What you are saying is cute, and it sounds like something a highschooler who was really into physics might say. It is wrong and incomplete though. Please stop reading pop-science, it will only confuse you, and lead you to bullshit. It is nice you like physics, but just please stop talking bullshit!

>photons from a distant star don't exist until YOU observe them.....random bullshit

This is just bullshit. And a horrible misunderstanding of quantum mechanics. WTF gave you such a shitty conclusion son? Explain your faggotry!

>>4765745

I think you need to read up and stop wasting everyone's time.

>>4765750
Just stop. You are just confusing concepts now. It is just sad

>>4765749
You make the assumption that probability, as humans understand it, is somehow built into the Universe. It is more likely that probability is just a human way of interpreting, with a small amount of certainty, things which we don't fully understand yet.

I doubt the Universe has randomness to it at all. It is more likely that it just seems that way to humans because of our incomplete understanding of the universe.

Tornadoes seems like random occurrences to humans. We can't predict them. We build probability density functions to determine where a likely spot of formation might be. Does this mean that tornadoes are probabilistic in nature? No. Tornadoes have a definite cause and will only appear when those conditions are met. Humans just don't have the information needed about them to draw definite conclusions.

Practically everything in the Universe sits in our human probability space until we have gather enough information about the phenomenon to explain it in 100% detail. Then probability has no meaning anymore.

>>4765760
Jesus Christ you are full of shit. Look up Bell's inequalities and come back again telling me that universe isn't statistical.

>>4765749
>The statistics of identical particles is one of the most important ....blah blah blah..... and is not intuitive at all you ignorant twat

It is actually very very intuitive. The stats for that kinda shit has existed for hundreds and hundreds of years. It is nothing new or special, and it taught in every freshman level probability and stats course (Even in alot of grade schools). It is pretty basic.

Its application to QM maybe relativity new, but it is pretty straight forward and easy to do.

>>4765758
Maybe I just have a better understanding of reality than what you are currently being preached by some dude who just feeds you 50 year old, disproved, theories in some classroom? Ever thought of that?

You are the type of person who told Einstein he was crazy about relativity simply because he wasn't attending the same college and lectures as you and thus has different ideas, and mathematical proof, about the Universe.

Our understanding about the Universe changes so rapidly now that by the time the words come out of your professor's mouth, they are likely outdated and at best, not the entire truth.

>>4765765
Just as I said, you don't understand what are you talking about.

>>4765749
>The statistics of identical particles

That is pretty ancient shit yo. I think I did that in kindergarden!

You have a bag of 5 identical red coins, and 3 identical black coins. What is the chance you pull out a red coin? A black coin?

>>4765765
I love listening to these people. They are like the modern day flat earthers.

Netwon: SEE MATH IT WORKS! This math shows that this is the answer! See MATH!

Einstein: Um... what if the math also alludes to a curved space time in which gravity operates?

Netwon: THE MATH DOESN'T LIE! LOOK! LOOK! MATH MATH MATH MATH.

Grow up.

>>4765766
>implying I'm still in school
>implying I didn't master relativity at least 6 years ago

LMFAO. You are too cute!

>>4765772
This is exactly what I'm talking about. It's _different_ for classical and quantum statistics.

>>4765772
I thought we were talking about Quantum Mechanics? The real question is what is the chance I pull out a dinosaur? The answer is, not zero.

We don't have enough information and thus statistics is needed. With more understanding we will no longer need them.

>>4765777
>implying I can't calculate the probability you will pull out a dinosaur

>>4765776
Just like the measurements for gravity on Earth seemed to differ from those in space. We could have used probability within the constraints of Newton's laws to derive the movement of interstellar bodies through space. Then Einstein came along.... and.... now we aren't ignorant so the mathematics has become definite. Just like Quantum mathematics might one day.

>>4765777
I don't think you understand what statistics is

>>4765780
>Implying your calculation of the probability doesn't inherently change the quantum system and thus change the probability before you can even calculate it.

>>4765781
You got me on the verge of tears, I... I give up. You win. Your stupidity cannot be defeated.

>>4765781
>Quantum mathematics

>>4765781
ARe you mentally ill?

>>4765788
Funny thing is those two is a single person.

ITT - A troll and a mad dude with a 4chan reaction image folder.

I'm out.

>mfw people cannot even into spin statistics
Fuck you people are retarded

Here, read the original paper written by Pauli
http://web.ihep.su/dbserv/compas/src/pauli40b/eng.pdf

It's trivial bullshit

And all particles are technically fucking identical, it's not even 15 like was stated earlier in this thread, they just have different observable properties because of representation theory

Mathematically, we live on a differentiable manifold with a compact lie group acting upon it

Particles are simply different representations of this lie group in terms of fields which live on the manifold, including the photon

sage for shit thread