Alex Hahn

PhD student
EQUS
Macquarie University
Road-tripping Sydney to Bendigo (2022)

What do you do?

You might have realised that not everything in our world is good. We had the pandemic during the past two years. Also, our planet is getting warmer so that the poles melt and penguins and polar bears lose their habitat. For humanity to overcome these issues, we need to develop new technologies. In the context of the pandemic, this would be new drugs to heal people or the vaccine to avoid infections. With regards to global warming, solutions could involve new types of battery to store a lot of power. One promising technology that is potentially able to find new batteries or drugs is quantum computers. These are similar to your laptop or computer at home but much faster. So imagine a snail (your computer) on a race with a rabbit (quantum computer). The downside of quantum computers is that they are very fragile, similar to a balloon filled with water. A very small perturbation can destroy them completely. This is where I come in.

I work on methods to protect the quantum computer from getting destroyed. More specifically, imagine again your quantum computer to be a very fragile balloon filled with water. It is so fragile that the air around us would act as millions of little needles trying to destroy the balloon. So what I am working on can be thought of as a fan that rotates very, very quickly. It creates some wind that blows away all the needles from the balloon. By this procedure, we are able to protect the quantum computer and ensure that it can perform all the important calculations to solve humanity’s big issues.

How did you get to where you are today?

Already as a child, I was intrigued by nature. I was collecting stones and sticks from the ground observing them for hours. What I always had in mind was: What are they made of? Why do they look like this? This intrinsic interest in the essence of matter followed me throughout my time in school. Therefore, I chose to focus on physics, maths and chemistry. It was at this point where I heard about the ‘standard model of elementary particles’. This is a theoretical model to describe what matter is made of, from the smallest, most microscopic point of view. To learn more about it, I decided to study physics and found my fascination for quantum mechanics. After a very mathematical training during my Bachelor’s and Master’s, I decided to do something more practical for my PhD. I also wanted to go abroad—outside of Germany, where I stayed my entire life. Therefore, I applied for a PhD at Macquarie University under the supervision of Daniel Burgarth. Our group is working on quantum control—the field that links fundamental quantum science to practical quantum engineering.

What’s the best thing about your work?

What I really enjoy about doing research is the freedom of thoughts. You are basically getting paid for thinking about interesting things and learning something new every day. It is just an amazing feeling if a calculation that you are doing works out and you know that you are—at least for a second—the only person on the planet who has ever seen this new result.

What advice would you give to someone considering studying science?

Science can be frustrating sometimes if things do not work out as expected. Studying is sometimes really hard and involves working long hours. But it is rewarding at the same time. Just stay curious and keep your drive. You will have a motivation for studying your subject, so always think about this when it’s getting tough. Also, many things that you will learn do not immediately make sense. Often, you will have to go through them many, many times. And even if you understand them, the motivation why you should learn these things is often not obvious. You will just realise much later what they are useful for.

What do you enjoy doing outside outside work?

I love spending time with friends. Especially during the weekends, I am always out with them exploring Sydney and Australia. We will go hiking or visiting another neighbourhood in Sydney for some cultural exchange. I also enjoy playing table tennis in Macquarie’s sports centre.