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December 16, 2022

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An interview with a Computer Scientist in Quantum – Professor Julio Hernandez-Castro, University of Kent

Having studied Mathematics and Computer Science at undergraduate level, followed by a PhD in Computer Science, Professor Julio Hernandez-Castro took up a career in industry, however, it was not for him. Julio decided to pursue a career in academia instead. He first took up a position in his home country of Spain but then moved to the UK and has not looked back since. Julio is now a Professor in Cyber Security at the University of Kent and works on multiple projects, including the Quantum Communications Hub, where he focuses on the certification of quantum random number generators. We caught up with Julio to find out more about his work, what his role involves and what advice he would give to others interested in pursuing a career in the same field.

You have a background in mathematics and computer science, can you tell us a little bit more about what inspired you to become involved in the field of quantum and your journey to where you are today?  

I grew up and studied in Spain, mostly in Madrid. I got a degree in Mathematics and Computer Science, and then a PhD in Computer Science. I then spent some time in industry but I didn’t like it very much. I was always interested in investigating new problems and so moving into academia to do research was a natural move. I also really like teaching and sharing  ideas with others and a university is the best place to do that. You can, of course, have an academic career in Spain, however, I thought by moving to the UK I would have more opportunities and that has definitely been the case. I moved here 13 years ago and so far, I am really happy to have made the move. There are many more opportunities to do research, and particularly to obtain funding for research, and I have benefitted greatly from this. I very much like the environment here, with regards to science research, compared with Spain. Despite recent challenges, such as Brexit, I think the community and the environment here is extremely attractive for international talent, and I hope that people realise that and we continue to bring the best talent to the UK. 

I have always been extremely interested in the concept of randomness. I think this is because it is closely related to mathematics, computer science and cryptography. I am interested in randomness as a mathematical, practical and philosophical challenge and I am convinced that the only way to achieve true randomness is through quantum technologies and so that’s what encouraged me to become involved in this field.

What are you working on at the moment and what are the applications of this? 

My work focuses on analysis of the randomness features of quantum technologies, specifically quantum random number generators (QRNGs).  I think randomness is a fascinating subject because it pushes the limits of the human mind in terms of being able to understand it. Also, as scientists, we are very focused on searching for patterns and inferring things from patterns within data, however, in randomness  there are no patterns at all, so it is one of the limits of science too, which is fascinating. In the field of cryptography, you need true randomness for generating secure keys. These are very important for data security and particularly in sectors such as finance, where you might be sending billions of pounds in a single transaction and any breach of security would have a devastating effect.  

There are not that many manufacturers of QRNGs at the moment and we lack proper standards for the technologies currently being developed. Standards are required so that devices are produced to a certain minimum level of quality, including a level of security. This is where my work fits in, I work on developing security certification for QRNGs. As part of this, I look at the resistance of QRNGs to side-channel attacks and their properties as randomness generators, including identifying biases and other defects. It is important that these things are investigated because if a random number generator is poor, it will compromise your security and privacy and mean hackers can access your data and communications. Although my work is on the analysis of QRNGs, I also work with the people making them because, after carrying out the analysis, we outline issues we find, make recommendations, and advise on what needs to change, so we influence the final design of their product. Certification and standards are really important in helping us to create a strong industry for quantum technologies here in the UK. Successive governments have been supportive of the development of the technologies and progress on certification and standards will help to enable a leading industry which takes up a significant proportion of future world markets.  

Can you tell us a little bit more about what your role involves and what a typical day at work is like for you? 

I work as a Professor at the University of Kent. I do research and teaching, so I must juggle both of those. Most of my time is spent reading papers, thinking about how to improve papers, following the latest developments of technology, considering windows of opportunity, preparing lectures, giving lectures, collaborating with people and meeting with my post-doctoral researchers to discuss their work. I really like working with my post-doctoral researchers as they are relatively early in their careers so I can give them guidance and mentor them. It is great to see them grow as they build up their research and their careers.  

What transferable skills do you think you have gained throughout your career and what do you think are the most important skills for working in a role like yours? 

I am an atheist and very much believe in scientific method, and I think skepticism is very important. As human beings we tend to be very social and try to follow orders and believe the stories that we are told. However, I think having a natural skepticism and therefore thinking critically about everything including God, politics or the latest scientific papers is very healthy in life and enables you to be a little bit less vulnerable to believing misinformation, for example. I think this comes from my mathematics background, and I think related to that skill of skepticism and critical thinking is having a good background in statistics. Finally, in this field, hard work is super important, you must be willing to learn new things across mathematics, physics, computer science and so on, to succeed.

What experiences do you think are valuable for someone hoping to hold a role like yours?

At the University of Kent, for example, we run summer internships and I think attending things like that is very useful for students. It helps them to see how the university works and what it is like to do research here. It enables them to understand how we can start with a problem, for which we do not even know if a solution exists and go about tackling it. I think for students to undertake an internship at a university local to them would be good. I would also advise people to read popular science and even science fiction. I think if you enjoy science fiction, chances are you will find true science even more fascinating. Doing logic puzzles or recreational mathematics can also be helpful and is something that I know a lot of people in this field enjoy. Of course, there are many ways to become a good scientist, but these are some of the things that spring to mind when I think of experiences that would be valuable.  

Is there a particular application of quantum technologies that you are particularly excited to see the development of in years to come and what are your hopes for the future? 

For me, my excitement is all around QRNGs as they are the only way to generate truly random numbers. I will be very happy and excited to see QRNGs within popular devices such as mobile phones in the next 5-10 years, giving individuals greater levels of security. This is already starting to become reality now as there are some smartphones in South Korea which contain QRNGs, but I look forward to seeing them everywhere, from everyday handheld personal devices to big high-security environments, and I am really excited to contribute to that happening. I am also particularly excited to see the UK industry develop.  

What would you say to young people who are considering pursuing a career in STEM, particularly in a role like yours?  

I have made many decisions in my life, however, the one I have never ever come to regret is studying mathematics at degree level. I think that was so informative and really set me up for the future, so I would encourage others to do the same. I did consider studying physics or another scientific discipline, however, I found that mathematics is so beautiful and is the best way to understand how the universe truly works. If you have a passion or an interest in mathematics I’d strongly suggest you study it further. However, science in general is very useful and we definitely need more scientists to tackle the problems that we have not yet solved, and to discover new ones. Taking up a career in science is the only way to create change that you know will remain and not be reversed. Of course, there are many other careers that make changes, law, for example, however, different governments can change laws and thus reverse the change you made, but that cannot happen in science and I think that’s incredibly powerful, and I encourage anyone who is interested to pursue a career in STEM!