An Elementary particle then is a fundamental constituent of matter
whose substructure is unknown so far.
Take as an example the electrons in the atoms or the quarks in the protons.
The rest of the particles are obviously not elementary particles,
but are constitued by them, electrones and quarks.
So, for instance: a proton is made up by 3 quarks.
This is clearly a really interesting field, because if it is true that all the matter is
constitued by these kinds of elementary particles we could have
a wider understanding of the universe by being aware of them and their interactions.
There is a really important factor in Particle physics,
called "wave-particle duality", which means that a particle
is not only a corpuscle but that it also has a wave nature.
We all have waves around us, so we know intuitively what a wave is.
Well, it turns out that a particle does not only behave as matter does,
(as we usually think)but also as waves do.
In this picture, (which is a real image) you can see that I clearly
exemplified the images of the waves produced by the effect
of two electrons in the surface of a crystal of copper,
merely to explain that an electron (a particle) produces a wave-like effect
in its surroundings when it moves in a surface. In other words
it can also be seen as a wave. It is actually this property,
when particles behave as waves do, what
allows us to understand this very important issue of Fundamental physics:
the relation between distance and energy.
Once we have identified this duality in a particle,
it is necessary to establish a connection between the inherent
properties to the particle and the ones inherent to the wave.
For instance, we know that a particle is characterized by a
determined mass and speed. Just like when we move,
we have mass and speed, well the same happens with a particle.
As I have just explained, a wave is characterized by a determined
wave-length and frequency, right? Well, when I study a particle in
its duality, as a wave and as a particle at the same time,
there will logically be a relation among these numbers, ok?
You can see this relation there, but it is basically
what I've already said: when the particle moves
at a high speed, it will have a small wave-length.
This is the speed in the denominator and this means "short wave-length".
In other words, this is a particle with high energy and speed,
but when this energy is studied for its wave behaviour,
it will have a short wave length (If we were considering that it had high energy).
To sum up, this is key in Quantum mechanics.
When high energy is reached, when we
considerably accelerate a particle, when it is full of energy,
What can we do? Well, we try to find
another particle in the way, which can be accelerated or at rest,
in order to make them collide so the energy of the first particle
is able, just as a microscope, to go to really tiny discances.
A big deal of the energy of this particle will look at really tiny distances
(in a quantic level) of the other particle. That is the
"Quantum key distribution". So, again, the summary would be that
we considerably accelerate the particles, we make them collide against
whatever we would like to study, it is like a microscope that will
get closer each time, so the more energetic the particle,
the smaller the distance covered: we would see
in more detail the hair of a fly, so to speak.
Therefore, particle accelerators are very poweruful microscopes.
Excerpt from the conference held
November 15th, 2013, at the Residencia de Estudiantes,
during the sessions "Las fronteras de la Física Fundamental".
Full video available at: www.eddaddeplata.org