quantum theory

Spooky action at a distance

Hi,
maybe you have already heard it.

“spukhafte Fernwirkung” or “spooky action at a distance” – Albert Einstein

what is it? Are we able to transmit information faster than light using it?

Spooky action at a distance or also quantum entanglement. This is very famous phenomenon which seems to allow information to travel faster than light, luckily not, otherwise we would have to throw all our physical theories to trash (or maybe it would benefit, who knows).

Particles have spin as I have shown countless times in posts about standard model or about particles and so on. They have also other properties which has to do with quantum entanglement.

What experiments shown was that when independently measure two photons for example the results about their attributes are correlated. This is indeed spooky because it does not matter how far away those particles are but always the result will somewhat be similar.

This cartoon helps explain the idea of "entangled particles."

The picture above from NASA page well explains how this works. The people there are detectors called superconducting nanowire single photon detectors which are cooled to be superconductive and when photon hits the wire it changes the resistance in the wire to some higher value so you can record the event.

Why does not this break the rules of speed of light? Because there is actually no data transmitted. You can not use it to communicate since the results are random anyway. And when you know your result you also know the result anywhere in the Universe, that does not matter because it was random.

I will just repeat: you need pair of entangled particles, for example laser beam can create photons that when they go through crystal and they split, they become entangled, measuring one particle will influence the other.

Einstein thought that this is because the particles contain what is called “hidden information”. That when they are created at one point in the crystal from the laser beam for example, that they make their “secret plans” on how their spin will work out when they are measured, which would not need any faster than light travel. In this video, Derek Müller shows the experiment of Bell that shows that there is no “hidden information” and how the measurements work, because what you can do is to measure the spin of particle in various angles which changes the probability of the particle to have that kind of spin.

Dragallur

 

 

Various fields for dummies!

Hi,
fields? Well yes, this is probably the last post before I will write about Higgs boson. Today you will learn that everything is made up of fields and that particle is just a special vibration.

Take for example magnet, it is something totally special if you think about it. Not that it sticks to stuff but that you can feel how it wants to stick without actually touching anything, just through EMPTY SPACE!

Magnet has his magnetic field all around, that is why we can feel it from some distance and the strength decreases with distance increasing.

On the picture above you can see lines of force around magnet.
This is electromagnetism and now we know that there is electromagnetic field around all the stuff that have charge. We know that we can magnetize needle using electric current.

This field is not only around magnets but also around all things that have mass, this is called gravitational field and even that it does not sound very exciting to us, in Newtonian age it was very cool when Newton found out that there is similarity between apple falling on his head and Moon orbiting Earth!

What happens when you start to rapidly move with source of electromagnetic field? Well you create waves. If you do it well enough such waves will create light! This light then comes to you in quantum! If you do it more rapidly you will get gamma rays and if you do it less rapidly you will get radio waves. This is just a vibration of field.

Or when you take radioactive decay. There is neutron which somehow changes itself into proton, electron and antineutrino. This is just a change of vibration in various fields.

Now there are 4 fields if I do not count Higgs field. What physicists want to achieve is the prove that all those fields are just one field and everything is just a various vibration of it, creating the effect of gravity, electromagnetism and so on. This would be the Theory of Everything.

Dragallur

Taking closer look on, NOTHING!

Hi,
in this post I want to look on literal nothingness, vacuum, empty space.
And why are neutron stars so freaking dense.

When you put your hands as far away from the other one and imagine that this is the volume of atom the nucleus is going to be thinner than the diameter of human hair.. well yes, that escalated quickly. And I am not even talking about electrons which are much smaller than protons and neutrons.

This simply means that you are, and everything you know, is mostly made up of empty space.

Now for the neutron stars.
Neutron stars are collapsed massive stars. They are extremely small and dense at the same time and the gravity of all the stuff keeps this stable.
Wow, neutron star is pretty scary when you take that their diameter ranges from 10-20 kilometers and at the same time they have 1.35 to 2.1 of Solar mass. The first picture corresponds to this, so if you would compress all humanity to size of sugar cube it would be as dense as neutron star. So in neutron star there is not much of empty space.

That is all for neutron stars but let me return to the empty space and vacuum.

Vacuum is extremely important, while I don’t want to list all technology using it, let me say that for example simple straw is working because of vacuum.
While you are not making the best vacuum ever, when drinking your juice from straw, you are lowering the pressure so the juice runs up. If you would lower the pressure a lot like in space this effect would be much stronger (you would not explode).

There is actually scale on Wikipedia about the levels of vacuum. OK now lets assume that you would be able to suck out all of the air and stuff inside closed box.
Is there going to be something?

Yes, it may sound strange but there is lot of stuff, and this stuff likes to change a lot.

Lets introduce you virtual particles!
OK, they are real kind of, at least it is known that they really exist. They have to do a lot with quantum theories like quantum field theory.. I do not understand any of it but that is not really important right now.

Virtual particles are particles that are popping in and out of existence all the time. In this kind of way they should be in pairs which then both disappear in nearly NO time. I read that since they are so virtual and may not carry any energy or momentum they may even travel faster than light or travel in time (this is questionable, as you will see (source Wikipedia)). Those particles are made in pair, one of them is anti particle so they then collide and annihilate.
For example there are virtual photons that actually do any kind of electromagnetic radiation, so photons are called force carriers of e. m. radiation. I already wrote about this earlier..

OK, I know that there must be something more to it since at the same time SOME virtual particles can travel faster than light as Wikipedia says, while force can not be transferred faster than the speed of light.

So there is all the stuff popping in and out of existence which is constantly annihilating. But when this happens on the edge of black hole when one particle is inside the event horizon and the other one outside, the one outside does not annihilate and it pops into existence and escapes the black holes gravity. Since conversation of mass/energy this must have taken something from the black hole. This really happens in what is called Hawking radiation, when eventually black hole can evaporate!
To watch something more about vacuum, check this video by Veritasium where he is talking about quantum fluctuations.

Dragallur

1st picture
2nd picture

Dimensions: Short Expansion

Hi,
here it comes, here it goes, again seemingly very favorite topic about dimensions. Last time I wrote about imagining higher dimensions and how they work and that we have 3+1 dimensions. 3 are space dimensions and one time dimension. Actually I should have added that there is and option of much more dimensions. Thanks to Joseph from Rationalising The Universe reminding me of this through his post which I recommend you to read.

Fine if you read his post you know that I want to talk about dimensions that can exist in string theory.

So there are two main theories: Theory of Relativity and Quantum theory.
What we know for sure that both are wrong. This is because TOR is not able to predict stuff on small scales and QT on large scales while they are both very good on their fields.
Then there is third guy called String theory. This theory says that on very small scale fundamental particles are one dimensional strings, which mean lines and when you are looking at them “from above” they look like particles.

String theory predicts a lot of dimensions on extremely small scales (check Joseph`s post to read about gravity etc.).
There are two most important ST theories. Boson and Superstring theories. The first one predicts 26 dimensions and second 10, now choose :D.
The thing is that actually for some stuff it is much better to have more dimensions.
Since for me it is so extremely complex I can just advice you for wiki page for start.
Still String theory is just theory as are others and I am totally looking forward to Theory of Everything!
Dragallur