Take 10 with... Cris Calude

Professor Cris Calude from the School of Computer Science gives us 10 minutes of his time to discuss how he uses probabilistic models to trespass classical incomputability and optimisation techniques to speed up some quantum computations.

Cris Calude

1.    Describe your research topic to us in 10 words or less.

What classical & quantum computers cannot do.

2.    Now describe it in everyday terms!

Most mathematical problems cannot be solved by classical computers and even less by quantum computers. I use probabilistic models to trespass classical incomputability and optimisation techniques to speed up some quantum computations.

3.   What are some of the day-to-day research activities you carry out?

I am working on three different projects with local and overseas collaborators, frequently talking on Skype/WhatsApp.

4.   What do you enjoy most about your research?

Almost everything.

5.   Tell us something that has surprised or amused you in the course of your research.

Once I was in a bus of an excursion organised at an international conference. After a while I told the person seating next to me that I was reading an exciting book on constructive mathematics, so we talked about it for a while. At the end my interlocutor introduced himself and ... surprise: he was one of the authors of the book. This was the start of a long friendship and collaboration with Professor Douglas Bridges who is to a large extent responsible for our move to Auckland.

6.   How have you approached any challenges you’ve faced in your research?

Keep an open mind and try not to be intimidated by authority. Greg Chaitin, the creator of a class of highly incomputable Omega numbers, told me once that there is no way to compute exact bits of such a number. To his surprise, with M. Dinneen and C. Shu (our PhD student) we computed the first 64 exact bits of an Omega number.

7.  What questions have emerged as a result?

How much can we push the boundary of such computations and how many bits of an Omega number can solve problems in a large class of mathematical questions; for example, 7,780 bits would suffice to prove the Riemann Hypothesis.

8.    What kind of impact do you hope your research will have?

I am not concerned about impact or rewards, I just enjoy doing my research.

9.  If you collaborate across the faculty or University, or even outside the University, who do you work with and how does it benefit your research?

I have many overseas collaborators, computer scientists, mathematicians, physicists. The long time collaboration with Professor Fred Kroon from Philosophy resulted in publications and a new course, Philosophy of Computation. 

10.  What one piece of advice would you give your younger, less experienced research self?

Choose two interesting open problems, ignore the literature and work on them with a fresh mind; later on, compare your results with what is known and continue.