Hi everyone my name is Mithuna and I'm a third year PhD student studying quantum
physics at the University of Cambridge. In this video I just wanted to explain
how I got here since what I started off in high school
I really wasn't into science. In fact I quite liked art. I mean you probably can't
tell from the quality of my illustrations these days, but back then I wasn't so bad,
and I really enjoyed it and I also really enjoyed English literature and
learning a second language and basically I really identified as a humanities student.
So what changed and how on earth did I get here eventually?
So the big turnaround came for me when I was 16 suddenly I understood what was
going on in science class. Maybe it was because I had a really great teacher at
the time or maybe it was because we were learning some really cool topics at
the time, but it made sense for the first time. I realized that science was about
coming up with basic laws that are simple and yet can explain so much
complex phenomena. So then after that I picked up this popular science book
which you might have heard of. It's by Bill Bryson and it's called a Short
History of Nearly Everything. I love that book and I totally recommend it. When I
finished that book I have this distinct memory of closing it and thinking I'm
gonna be a physicist. And yet it wasn't such an easy path. For one thing I was
still absolutely terrible at maths. At the age of 13 when we start high school
we had taken a test that would show us whether we were good at maths or not
apparently, and then according to that we would end up in different levels of
maths class, and I was placed in one of the lowest maths levels- in fact almost
the lowest maths level -and I'd stayed there for all these years. Suddenly I
realized that if I wanted to be a physicist I would have to do quite a lot
of maths, so I decided that I would take the highest level of maths that they
offered at my school and I asked my maths teacher at the time whether he
thought I would be able to do it. He laughed and walked away... but he couldn't
stop me and so I did it anyway -even though my teacher the next year really
really tried to persuade me to drop the class. In my final year though I had a
fantastic maths teacher and I finally realized that actually a lot of the
things that I liked about physics were the same things that I could like about
maths - that you can take simple rules and use logic to be able to solve
complicated problems. I still struggled a bit with maths and so it wasn't my very
favourite subject. That was still definitely physics. At this point I
remember I often would skip having lunch with my friends so I could go to the
library and read physics textbooks.
In my first year of university I did physics and chemistry along with a
second language and a maths course. The maths course that I picked though wasn't
the one meant for people who wanted to become mathematicians, it was the one who
meant for people who were interested in engineering, let's say. I decided to do
that course because I was still not feeling super confident about my
mathematical abilities. In that course we learned about linear
algebra which is super beautiful- I love that you can just visualize what's going on.
At the same time though I was starting to feel more and more
disillusioned with physics. Ironically the final nail in that coffin was
quantum mechanics in second year. Quantum mechanics was this course that I was
super excited to do because it was meant to be about like the strange laws that
govern physics... and yet quantum mechanics class was mostly about solving this
partial differential equation for different boundary conditions. I'd come
to physics because I thought that I'd learned how to solve problems
but instead I felt that I was just learning how to use mathematical
formulas. At that point I was feeling quite lost
but I got very lucky because the next semester I decided to take a course in
abstract algebra for no other reason then that it sounded similar to linear
algebra, which I really enjoyed. This course was meant for mathematicians and
so in particular it was meant for people who had taken the hard math courses the
year before and in the semester before which I hadn't, so I was completely unprepared.
I took the course anyway and I ended up loving it.
This was the first time that I'd met pure maths, and pure maths is all about
taking axioms that describe a particular type of system and then from those
axioms driving lots of properties of that system that aren't obvious. It
had a lot of these elements that are really liked about physics but it was
very very rigorous which was actually quite a challenge for me, because up
until this point I was a very intuitive kind of person. Even in physics I would
give very hand-wavy arguments for things and I would just think that certain
things are obviously true and because it's obvious to me but they're true I
wouldn't need to show that they're true. Whereas maths is the complete opposite,
and I really really did struggle because of that culture clash. But it taught me
so much and I after that was completely hooked on the pure maths way of thinking
and I decided to switch my focus from physics to maths. The Bachelor of Science
was very very flexible and so I did a bunch of other subjects as well. I
decided to take a course in information theory because thermodynamics has this
quantity called entropy in it and information had this quantity called
entropy in it and I was just wondering, are they the same thing or not? So I did
this class that was meant for computer scientists I was the only not computer
scientists in the class and it was so cool -no matter what discipline you're in
I would recommend information theory. It has such deep consequences for basically
every other subject of human knowledge. In my final year of undergraduate I took
a course in functional elseis which is basically the maths of
quantum mechanics and it's basically linear algebra on steroids. I really
loved that and so I had this crazy idea that I would become a mathematical
physicist who focuses on the maths of quantum mechanics. So basically I would
become a physicist just to have an excuse to be able to do maths that
applies to the 'real world'. I'm so glad that I didn't end up there and the
reason I didn't end up there is because of this channel. For some reason I made
a couple of videos about quantum mechanics.
I made them about quantum mechanics, I think, just because I thought well I
understand quantum mechanics. I've been doing all these courses on quantum
mechanics, surely I could explain it. And I loved explaining things so I just kind
of made some videos. Those first two videos were absolutely shocking and not
just because of the quality ...although that is pretty hard to look at now, but
also because of the content. See, I decided that these videos wouldn't have
any maths in them because they were meant for laypeople but when I have to
take away the maths I realized I didn't understand quantum
mechanics at all. Sure I knew how to solve the Schrodinger equation and I
knew what Hilbert space was but, when it came down to what does quantum mechanics
actually say about how the world works, I had no idea. That's why when I finished
my undergraduate degree I took six months off and started learning quantum
mechanics. Like properly learning what it meant and as I learnt things I made
videos about them. Most of those videos are now unlisted but I was actually
really productive at the time I made it like 20 videos or something. On this
journey of learning quantum mechanics from my bedroom I met Bell's Theorem for
the first time and started thinking about the foundations of quantum
mechanics and hidden variables and bohmian mechanics and all kinds of crazy
stuff like that and I just loved it so much -and that's when I realized this is
what I want to do. I want to study quantum mechanics but properly study
quantum mechanics. Not as a mathematician trying to
just manipulate symbols, but to actually understand what was happening. That's how
I ended up doing a honours (which is sort of like a one-year masters) in physics
rather than maths and I had to pick a subject to do my thesis in and I chose
quantum computing (and information) -not that I knew anything about quantum computing but
because it had the words quantum and information which I already told you I
was very interested in but also computing which I'd learnt about in a
course on logic and thought was super fascinating as well, so I thought the
combination of these must be cool. And it turned out I was totally right. Quantum
computing is a fascinating field. See quantum computers are computers that use
the spooky laws of quantum mechanics to do calculations faster than it should be
possible for a classical computer to be able to do them. When this was discovered
people were really surprised because there are many different ways to build a
classical computer and yet they all end up being equivalent -they can all solve
the same class of problems to the same sort of efficiency - and so it doesn't
really matter what kind of model you're looking at. And yet when you make this
other model of computing using quantum mechanics suddenly it does matter and
the class of computations that you can do is different and so this means that
quantum mechanics obeys some fundamentally different logic to regular
classical mechanics. So there's this big open question in quantum computing which
is why? What exactly is so special about quantum mechanics? Exactly which part of
quantum mechanics is allowing for the speed up to happen? That was what I was
interested in in my honours thesis. I obviously didn't solve it but I decided
that I wanted to keep studying this particular topic and that's why I ended
up on almost the literal other side of the world, because my supervisor here in
Cambridge is one of the people who's really interested in
the question and has done a lot of work on it in the past and I wanted to work with
him, so I applied and somehow ended up here. So that's my story of how I went
from someone who thought that she was terrible at maths and science and ended
up as a quantum physicist. If I have any moral or any advice at all it's that I
want you to be open-minded about the kind of things that you could enjoy if
you gave them a go, but also be open to minded about what you could get good at
with practice. So thanks for watching this video this
is the first time I've had my face on these YouTube videos and I'm really
nervous about the comments.. so please don't leave me anything too weird. My mom
reads them. I'm just kidding she doesn't even watch my videos. Anyway you know
what I mean. Also the video about Hilbert space and Dirac notation and the maths
of quantum mechanics- I'm writing it right now and that means that it should
be coming out soon which means that it should be coming out within the next two
months, probably. Hopefully sooner!