If light is matter why doesn't it collide with other light?

Light is waves. Waves don't collide, they do interfere though.

Basically the exclusion principle lets any number of bosons be in the same quantum state, you can do the same thing with ultra cold (bosonic!) Atoms.
Afaik, they will still collide though, but also they are almost at rest while light travels, well, at the speed of light.
The question of whether or not light can collide with itself is current research, I know at least one group at U of Michigan is investigating it.

You got an intuitive way of explain why Fermions can't occupy the same space like Bosons? Is there any analogy that might explain it? I dont understand the significance of the spin energy levels(?) Or spin states.

It does.
This board is terrible.

>You got an intuitive way of explain why Fermions can't occupy the same space like Bosons? Is there any analogy that might explain it
No, because it's an intrinsic quantum effect, so it doesn't have a classical analog.

The basic principle relies on the fact that QM particles are indistinguishable, so if you have a multi-particle wavefunction, it must reflect that. If you gave spin-1/2 particles, their wavefunction will flip sign if you exchange them, meaning it is anti-symmetric and 'repulsive' in a sense that two particles cannot be in the same quantum state, since otherwise the wavefunction would have to be zero in order to flip sign under exchange.
For bosons the wavefunction is symmetric and you can have an arbitrarynumber of particles in the same state, since it will always be the same, no matter how you shuffle them around.

[citation needed]
I can also make an arbitrary Feynman diagram and claim I found new physics

Your diagram depicts elections and anti-elections absorbing and emitting photons though. Where is the collision?

I wasn't aware elementary quantum electrodynamics is in any way new or controversial.
It depicts scattering of photons to photons through a fermionic process.

Thanks. Would it make sense to say that a multi particle wave function with fermions would lose information about what it contains because there are multiple ways to make it up from different fermions then? I'm just trying to understand it.

I think I have to read more into it. I like to actually understand stuff, but QM is a wall without going into really complicated math from what I been able to find.

>Would it make sense to say that a multi particle wave function with fermions would lose information about what it contains because there are multiple ways to make it up from different fermions then?
I've never thought about an information based approach, but it feels like you are right about it.
>I like to actually understand stuff, but QM is a wall without going into really complicated math from what I been able to find.
Most of it only linear algebra, it just gets clouded by weird physics notation so you don't recognize it easily.

then why is if affected by black holes?

Because the black hole curves spacetime making the straight path curved.
Lrn2geodesic

They aren't matter matter doesn't exist imo

>imo
neither does your opinion

because it acts as a wave and a particle

...

It travels at the speed of light

Mass is another form of energy. Light is energy. What causes gravity, rather than mass, is energy. You could have a pure-energy black hole, which would be called a Kugelblitz.

headup display does this every morning

You have a best of an point there my good Sir
light is electromagnetic wave is not exact straight line

It does if somebody shines a flashlight at you and then you shine a flashlight back at them then their flashlight appears to dim because some of your flashlights light outlights the other flashlights light

No. Wavefunctions obey superposition. The only thing you find when looking at the probability of finding multiple Fermions in the same place at the same time is 0 for the reason stated by the other guy.

Who says it doesn't?
Photons have spatial extension (non-zero radius) and therefore they have volume.
Photons contest each other's space and therefore they have density. They *do* collide with each other:

>But now scientists have spotted evidence of photons bouncing off other photons at the Large Hadron Collider at CERN, the European particle physics lab in Geneva.
sciencenews.org/article/lhc-atlas-photons-interact-physics

You can put microscopic objects into rotation by directed photon bombardment. Clearly photons are colliding with other particles (not just photons).

Mass is a function of density and volume. Photons have both. In fact all matter is made out of agglomerations of photons. It's why E=mc^2. m = density*volume of photons. The first 'c' is the linear velocity of the photon and the second 'c' is the spin velocity of the photon.

The Pauli exclusion principle states that no two identical fermions can exist in the same quantum state in the same quantum system, but photons are a type of boson so this principle doesn't apply here. Also there are no fundamental forces at play with photons other than gravity, but since photons are elementary particles, they are effectively an infinitesimal point. This means that two photons can exist in the same location without interacting.

no, but ever since i came home from college (im staying for a year and then getting my masters) she has been super sexual towards me, even insisting to sleep with me often because of night terrors, but i feel her masturbating next to me sometimes.

though, to be fair, our dad killed himself while she was barely in middle school, and then i left that same year so she is very damaged.

>through a fermionic process
stills doesnt mean bosons can collide,

gluons can stick together? but they arent photons, photons cant collide.

Those are virtual particles

this board always has been

cerncourier.com/cws/article/cern/66878

more?

What is energy though?
How was it formed

>The phenomenon manifests itself as beams of nearly real photons,
wtf is a nearly real photon? I already accepted that virtual particles exists, but come on, nearly real particles?

Then you have never seen the 57274738 quasiparticles in condensed matter physics.

Phonons, skyrmions, holons, Bogoliubov quasiparticles.

In the end many things are just mathematics more than physical reality

Nah, I'm totally fine with quasi particles, virtual ones are sketchy but I guess it works.
But 'nearly real' sounds literally retarded

>this precisely defined and empirically established phenomenon confuses me, who has no clue about quantum field theory
>surely everyone else is stupid

Virtual are a bit sketchy but not as sketchy that antiparticle go backwards in time.

Or what always confused me in my QFT class: Why are the Eigenvalues of the Time inverse operator squared i.e. T^2 ± 1?

If I would use the parity operator P twice: P^2 it's logically 1

>Light is energy

I'm retarded, bear with me

Does this mean light could theoretically have mass under some circumstances?

If it's so precisely defined, pls explain it. What makes a particle "nearly real" compared to being a virtual particle, a real particle or a quasiparticle?

Never took QFT, but I'd feel it has to do with the fact, that time only moves one way while space can go both ways.
About those anti-particles, aren't they just the negative solution of the Dirac equation? Would make sense to me then.

Alternative thinking
Light is a high dimensional particle

When we deal with high dimensions object to project it's location point in lower dimensional you get more than one answer

For example
by Newton law
0 mass can mean
no momentum or always stop, go as speed of light
By Einstein law
not bending space time or go as speed of light, have mass equal always stop

Newton equal oppersit with Einstein
And all 4 answer was right because light as 3D object is 4 projection at the same time

...

actually, it does. Nonlinear quantum effects.

Continued...

If light can be 4 point in 3d space

Look at the Moon the distance is about 300,000 km or 1 light second
2 particle of light stop at moon surface
2 particle of light travel at light speed and hit your detector

2 particle that hit you , give you it's own kinetic energy to you as momentum
1 particle is normal particle carry surface of time dimension +1 second
1 particle is anti particle carry surface of space dimension -300,000 km

After detect , detector got -1 second , +300,000 km
That why you can see a thing with light

And anti particle with - properties is in Quantum point of view.

Continue...

All 4 point of light kinetic energy is

+1 second
-300,000 km
-1 second
+300,000 km

Summary of energy is always 0
Particle need it own surface of dimension
That another 4 type of space-time-gravity dimension
The symmetry's is 4 particle and 4 3dimension ( of space of time of gravity)

The super symmetry supposed to be a pair if my example but first you need to unlock your mind
Because Sci today standard for me it's upside down.

For OP
The Answer is light not travel in space, -300,000 km mean its jump like electron change orbit but light orbit can be

>light not travel
>When particle jump , its automatically go to shortage distance

But we can see it travel

>Operators
I don't think that's the whole picture. If you would change time 2 times, why do you end up with negative time? That's fishy

>Dirac equation
That's partly true. If you take the Klein Gordon equation you have 2 solutions, with one being antiparticles.

One way to derive dirac equation is by taking the root of the derivatives of the KG-eq. (Which is not a well defined mathematical approach, but dirac introduced the slash notation and can take the root via gamma matrices).
The dirac equation itself is only a description of fermions. Like KG-eq. (Which describes bosons) the dirac equation has antiparticles solutions as well.

But still, I have no idea why T^2 has eigenvalues ± 1

Came here to post this.

This is an [math]\mathcal{O}(\alpha^2)[/math] term in the series expansion for the scattering matrix of two photons. It's contribution is incredibly tiny, but has effects measured at very high energy (or similarly very strong electric fields). In particular, photon states can become polarized when passing through a region of high elective field because of this phenomena. This has been measured in light passing near neutron stars.
space.com/34852-neutron-star-shows-quantum-property-evidence.html
The actual papers are not hard to find either.

*electric field

Probably to keep CPT. For example the Dirac Lagrangian is linear in the time derivative, so the fields must transform to cancel this negative sign that appears from the derivative term. Roughly speaking...

Light is composed of 'force carriers,' which are particles that transfer between particles via 3D lines that lead to the south pole - the north pole ejects force carriers like photons.

A force carrier (Which includes photons) isn't a 'real particle' like a proton or electron is - it's like a value transfered between real particles. So when you see light, what you're really seeing is the level of energy being transfered between you and the illuminated object - brighter and closer means more energy, and dimmer and further means less energy.

I disagree with this post. Not all light is virtual.

>light could theoretically have mass under some circumstances?

Sure. Two photons going in different directions have mass.

Wave-particle duality