In so many aspects quantum physics is something that we barely know, We have so many theories that apply in real life but we have others that are on constantly study. 

In general, the advance in a field provokes more questions than answers. And that is something that never ceases to amaze. It gives the feeling that we always go several steps behind nature

Keep in mind that in these answers and these ramifications are not linear but to the same question, you can usually give several answers. The only way to stay with the correct branch is: THE EXPERIMENT

# Quantum and Relativity theories 
#

At the beginning of the 20th century, We have two very well defined theories

1) * **Quantum mechanics** That forced us to stop thinking about particles following defined trajectories, that taught us that a system can be here and there with a certain probability and that was the most important conceptual revolution in the history of humanity

2) * **Special relativity** In this theory, we learned that the speed of light in a vacuum is constant for inertial observers, that space and time were not absolute entities and that energy and mass were intimately linked.

# How does quantum mechanics particles move at speeds closer to the light speed?
#

With surprise it, We saw that it was not possible to describe a quantum particle with relativistic velocities. In fact, what happens is that if you try to do that you realize that you have to describe an infinity of particles for the theory to make sense, that’s it, if we join the quantum and relativistic teachings we can not speak of a single particle but of something known as a field. (A field is defined in all space-time and quantumly has excitations that behave like particles, that’s it, they have a defined mass, spin, and charge).

In addition, thanks to [Dirac](https://en.wikipedia.org/wiki/Paul_Dirac), we saw how the content of matter in a relativistic quantum theory doubled and the concept of antimatter appeared.

Therefore, joining two theories that work well leads us to the question of how to treat fields quantumly.

# Quantum Field Theory
#

Quantum field theory is the branch of physics that deals with systems that satisfy the principles of quantum mechanics and special relativity, and as we have said, we can no longer speak of individual particles in this context.

<center>https://plato.stanford.edu/entries/quantum-field-theory/cm-qm-qft.png</center>
<center>[Source](https://plato.stanford.edu/entries/quantum-field-theory/cm-qm-qft.png)</center>

The problem became when we realize that there were calculations of physical processes in the quantum theory of fields that gave infinite results. This is a clear indication that the theory cannot predict anything more than it without senses.

And here is when a big problem arises, one relies on relativistic and quantum principles, and yet their union produces theories that gave us an infinite useless result, So physicists forced the machine to find something that eliminated the infinities: **THE RENORMALIZATION**.

# Interactions
#

_Can we have quantum theories of fields that explain the interactions between elementary particles and that are renormalizable?_

Here is where [Martinus J. G. Veltman](https://en.wikipedia.org/wiki/Martinus_J._G._Veltman) and [Gerardus 't Hooft](https://en.wikipedia.org/wiki/Gerard_%27t_Hooft) demonstrated that there is a class of theories that are always renormalizable and therefore give finite results to the physical magnitudes, these are the [gauge theories](https://en.wikipedia.org/wiki/Gauge_theory).

<center>https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Feynmann_Diagram_Gluon_Radiation.svg/211px-Feynmann_Diagram_Gluon_Radiation.svg.png</center>
<center>[Source](https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Feynmann_Diagram_Gluon_Radiation.svg/211px-Feynmann_Diagram_Gluon_Radiation.svg.png)</center>

It turns out that if we want to decide to use the gauge theories for this to be consistent you have to accept that:

* **All the particles that surround us are particles without mass.**

This obviously goes against all the accumulated experience, There are massless particles like the photon, but most of them have their mass.

Does gauge leave us a theory for predicting something meaningless? The answer is no, And it is not because the gauge theories are elegant, they are beautiful and give us interactions, which are not little They are also renormalizables and give us finite results. So  the option is to put something that is consistent with the gauge theory giving  mass to some particles: THE HIGGS MECHANISM.

# The Higgs
#

>  The Higgs boson is an elementary particle in the Standard Model of particle physics. First suspected to exist in the 1960s, it is the quantum excitation of the Higgs field, a fundamental field of crucial importance to particle physics theory. Unlike other known fields such as the electromagnetic field, it has a non-zero constant value in vacuum. The question of the existence of the Higgs field became the last unverified part of the Standard Model of particle physics, and for several decades, was considered "the central problem in particle physics" [Source](https://en.wikipedia.org/wiki/Higgs_boson)

<center>http://c3.thejournal.ie/media/2012/07/Higgs-boson1-390x285-390x285.jpg</center>
<center>[Source](http://c3.thejournal.ie/media/2012/07/Higgs-boson1-390x285-390x285.jpg)</center>

Without going into so many details let's say that all the particles are diving in a Higgs field that is everywhere. There are particles that have a greater affinity for the Higgs and therefore Higgs particles are grouped making it a "fat" particle with mass and there are others that ignore the Higgs and move through it freely, without mass.

Well, that's it, we have everything solved. Almost.. a problem arises with this. When one sets out to study what mass the Higgs should have and therefore the particles that interact with it to acquire its own mass, we get a surprise. The mass of the Higgs is of the order of the mass of Planck, that it does not matter what is worth now,  but that is a barbarity for a particle. Our machines do not produce that energy concentrated in a particle, we have several zeros below that.

And now another question arrives

_Why does the theory tell us that the Higgs has to be very large and our particles are very very light compared to the Planck mass?_

The temptation is to get rid of the Higgs and look for something else. Well no ... it is not so easy to find a mechanism of mass generation that is compatible with gauges theories. So we have to find another mechanism that lowers the Higgs mass from the mass of Planc to the masses we see around us, and one of the possibilities is: THE SUPERSIMETRY.

# THE SUPERSIMETRY
#

Supersymmetry is based on the fact that it is possible to find a mechanism that for each bosonic particle there is an associated fermion and vice versa.

<center>http://www.hephy.at/fileadmin/user_upload/Theorie_SUSY1.jpg</center>
<center>[Source](http://www.hephy.at/fileadmin/user_upload/Theorie_SUSY1.jpg)</center>

If we introduce a fermion for each known boson and a boson for each known fermion then the Higgs acquires a short mass, which we see around us in the particles.

The problem is that we have no record of the existence of these supersymmetric particles yet, but surely it will be a technical problem that we have not yet reached the energy necessary to produce them. 

A more serious problem is that when introducing supersymmetry the theory is consistent with the Higgs mechanism and the mass of it is short but it happens that tells us that the proton has to disintegrate (in a short time compared to the life of the universe). Unfortunately (this is ironic because it would go bad otherwise) the proton, experimentally, has a life comparable to the age of the universe.

So far, Do we  have a Solution? Yes, R-Simmetry 

# R-Simmetry
#

So If we want that supersymmetry does not destroy our matter, we must put into our theories a relation between supersymmetric things. That's what they called R-Symmetry,the problem is that if there is that then apart from electromagnetism, the weak interaction, the strong interaction and the gravitational interaction we should see other interactions that we certainly do not see.

_Disclaimer: This is a compilation of my research and my own conclusion_ 

# References 

* https://en.wikipedia.org/wiki/Renormalization
* https://plato.stanford.edu/entries/quantum-field-theory/
* http://www.mdpi.com/journal/symmetry/special_issues/symmetry_in_quantum
* https://ncatlab.org/nlab/show/R-symmetry
* https://www.scientificamerican.com/article/what-exactly-is-the-higgs/

<center>https://steemitimages.com/0x0/https://steemitimages.com/DQmcwqJQxGf2mm6i6PF8ibhPsPZjcn9L596SoMXWFDp91JY/steemstem.gif</center>