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>> Ordinary matter, broken
into its smallest pieces,
is made of particles:
protons, neutrons, electrons.
But what if we could create
new kinds of particles?
Well, it turns out this is possible in
Condensed matter physics.
They're called quasiparticles.
Mathematically speaking,
a particle is a wave or
an excitation in a quantum field.
But the same mathematics also
applies to magnetic materials.
If we have an array of
interacting magnetic atoms,
shown here on the bottom, we
can create a wave of magnetism
moving through this material.
And we can use the
mathematics of particles, from
Particle physics, to describe this wave.
It looks and it acts like a
particle, and so we call it
a quasiparticle.
Now, these quasiparticles are not just
mathematical constructs,
they're actually used to create
electronic devices.
One very well known quasiparticle
is the electron hole,
which is the basis for the transistor,
the integrated circuit
and the modern computer.
But there are many more
kinds of quasiparticles
that are predicted to
exist, which have even more
bizarre properties.
And because of their unique properties,
mathematicians have
proposed that they be useful
for creating new kinds of electronics or
ultra-fast quantum computers.
The trouble is, these quasiparticles
are extremely difficult
to detect.
It's a bit like someone handing
you a box and telling you,
without looking inside, you
have to determine the shape
of an object that's on the inside.
So we have to rely on all
sorts of indirect measurements
to infer their existence
and their properties.
In my thesis research, I've
used a technique called
Neutron scattering to peer inside the box
and look for new kinds of
magnetic quasiparticles.
Neutrons are particles which
are chargeless, so they pass
through material very easily,
but they are magnetic,
so they get deflected by magnetic fields.
So, in my research, I
took many newly-discovered
magnetic materials, placed
them in a neutron beam,
which is generated by
a particle accelerator,
and watched how the neutrons
scattered off the material.
And then we took this
data and we compared it to
computer simulations and
looked for signatures of
quasiparticles in the
data that we collected.
Now, the research that
I did was exploratory,
so, for most of the
materials, we had no idea
what we were going to see beforehand.
But I did ha- find some
interesting results.
In one material, I found a
quasiparticle that exists only
on the surface of the material,
but not on the inside.
In a different material, I found
evidence of a quasiparticle
that moved through prescribed
channels through the material,
instead of moving freely, like most do.
And in a different material,
I found quasiparticles
that act like magnetic
north and south poles,
which move around
independently of each other.
And all this has given
us a better understanding
of what quasiparticles are
possible, and the materials
that they are found in.
The entire silicon age
was founded upon a single
quasiparticle: the electron hole.
Just imagine what we could
do if we had a whole library
of quasiparticles to choose from.
And this research has
taken us one step closer.
Thank you.
(audience claps)
