A little over a month ago, science media all over the world were
hailing Leo Kouwenhoven's discovery of the
Majorana fermion particle. Now, the work of his team was published in Science Express.
ScienceGuide talked to doctoral candidate Vincent Mourik who was
part of the researcher group that made this major breakthrough.
Mourik explains his fascination for the Majorana quest, what
challenges his team faced along the way and what this discovery
could mean for quantum computers.
Pure curiosity
You and your team are investigating Majorana fermions. Why
is that?
It all starts with curiosity. Finding and understanding this yet
unknown particle is really something new. It has characteristics
which have never been observed before. That is why I dare to say
that its discovery might be truly revolutionary.
So what you are saying is that you were trying to discover
it simply because you can.
Fundamentally yes. You know for years nothing much happened in
this field of science. We were looking for the Majorana fermion and
what drove us was scientific interest as an end to itself.
How did you start your search for this rare
particle?
I was studying technical natural sciences in Delft and through
my final university project I got in touch with the research group
surrounding Professor Leo Kouwenhoven. His team was part of the
Kavli Institute of Nanoscience, a very prestigious organization.
That was around two years ago.
Back then, the whole idea of looking for the Majorana fermion
was just at its beginning. Leo and his postdoc were contemplating
ways of tackling this quest. They concluded that they could do this
right here at Delft University. At that point in time, I was still
looking for a topic I would focus on for my PhD thesis. I took the
chance and joined their team which was quite a fortunate decision
as it appears now.
Synthesize or collide?
So how did you ultimately go about the search?
Basically what we did is that we created these particles
ourselves by combining a number of ingredients. Of course there are
a lot of theoretically appealing ways of detecting these kind of
particles. Our goal, however, was to go beyond these theoretical
concepts and make our search concrete. The know-how for this was
right there in our team. We translated that into a practical
experiment.
Science media all over the world are hailing what they
describe as an "incredible" approach to realize a major
breakthrough. What was unique about your work?
Well, if you consider that it took us only two years to detect
such a fascinating particle, it is quite exceptional what we
achieved. All we used was one tiny computer chip at little cost. I
guess that really distinguishes ourselves from others.
At CERN for instance experiments are conducted at a much greater
scale. The people working there do an amazing job. Their approach
is different, however. They are trying to detect particles by
letting them collide with one another. By contrast, we were acting
more like 'engineers' creating a system instead of only measuring
results of a collision.
Breakthrough for quantum computers
What do you believe will the impact be of your
discovery?
Our ultimate goal here at the Kavli Inistitute is still the
creation of a quantum computer. We want to build a computing system
that works based on the smallest particles you could think of.
Majorana fermions are of great interest in this context. What we
discovered can become a key component of future quantum
computers.
Theoretically, research has shown that it is possible to build
nano-sized computers. But they are very vulnerable to interferences
from their environment. This would not be the case if you employ
quantum bits with Majorana fermions. We believe that these are much
more robust.
This is really important. Since these fermions are much more
stable you can use them to create hard disks for quantum computers.
That is also why Microsoft is very interested in the research we
are doing.
Because of these unique features, scientists all over the world
were looking for the Majorana Fermion. The very elite of our
discipline was put to the task. That means we are talking about 50
teams all over the world working on this, from Harvard to ETH
Zurich, from MIT to Chinese institutes. We hope that this
competition is over now. Everybody know that our quest to find the
Majorana Fermion was successful. And it was our team in Delft that
made it.
Nobel prize candidate
Two years you were working heavily on this project. Was
there also a moment when you starting doubting the success of your
mission?
For the past two years we were extremely busy. But of course
there was also a phase when we made no progress. We needed a
certain new material to conduct our experiment. It was made of nano
wires and our colleagues at Eindhoven University were particularly
skilled at working with it. We had to combine this material with a
superconductor. That turned out to be a very challenging task and
for three months we really got stuck.
Twenty, maybe thirty times we tried to combine those parts
without success. Every time we failed we had to see again what went
wrong. But then after a lot of attempts it finally worked...
There is a rumor among the Dutch technical universities that
this discovery might be Nobel prize worthy.
Well, this depends. The real question is what we do with this
discovery. Majorana particles have a similar potential like graphene. Everybody understands that. What is
important to see is that Andre Geim did not only discover graphene,
but he worked intensively on follow up research showing its
potential. That is really smart.
So we cannot just leave the discovery of the Majorana fermion as
it is right now. Instead, we have to look for real world
applications and see what else we can find out about its
characteristics. What can we do with it, that's the real question,
isn't it? If we manage to build on this, the basis for future
quantum computers may be laid out right now.
If you would like to have a look at the data underlying the
experiment, click here. For a complete press release by TU
Delft, click here.