The Dean of Science Award honours Master’s students in the Faculty of Science who demonstrate outstanding performance. We sat down with the latest winner in the Department of Physics and Astronomy, IQC researcher Sainath Motlakunta, to learn more about his award-winning research.
Congratulations on your Dean of Science Award, Sainath. Let’s start off by talking about your Master’s thesis. What did you research?
My group and I work on trapped ions. Our ion trap is designed to trap a string of ions, where each ion is a qubit in a quantum processor. The aim of our research is to perform quantum simulations that will allow us to study physics too complex for classical computers.
The main part of my thesis was a theoretical exploration, but there was also an element of setting up the lab for experimental implementation. I, along with my collaborators, developed an experimentally feasible, scalable protocol to simulate spin systems of two-dimensional (2D) lattices using a one-dimensional (1D) string of connected trapped ions.
And what makes your protocol different from already existing ones?
Quantum simulations with trapped ions are broadly classified into two categories, analog and digital simulations. In an analog quantum simulation, you exactly replicate the system Hamiltonian—the rules for how a quantum system will evolve over time—in your simulation. This method restricts you to a few classes of Hamiltonians. In a digital quantum simulation, you break up the evolution of a Hamiltonian into multiple single- and two-qubit gates, and then you apply those to your quantum system. That method has its own problems, such as the scaling of errors with system size.
We developed a hybrid analog-digital protocol, which is more versatile than the analog method and less error-prone than the digital method. The protocol also takes relatively fewer experimental resources than other quantum simulations. Most protocols would require fully addressing each ion in the string individually, whereas this new protocol doesn’t. Our work was published in Nature Partner Journals Quantum Information.
The power of this protocol is that you can switch between spin geometries during the evolution of the system, which is not physically possible with any other physical implementation. This allows us to study the rich physics at the boundary of transitions between phases of matter. No one knows what happens during phase transitions between different geometries, so it will be really exciting to explore them with this protocol.
What challenges did you face during your masters?
My Master’s was a little bit funny. I was in a different research group for my first four terms, but then I had to switch. I only had two terms to complete a whole new thesis. I couldn’t have done it without my supervisor Rajibul Islam, Fereshteh Rajabi, a postdoc in our group, and Kevin Resch and IQC, who helped make my switch possible. I was lucky because the group had this problem lying around, so I was able to pick it up right away and get to work.
What does the Dean of Science Award mean to you?
It is very encouraging. I was worried because I had to rush my thesis. Perhaps, I thought, I could have done better with more time. But after I won the award, I no longer felt any regret. My work was validated.
What’s next for you?
I am staying at IQC to pursue my PhD. We’re in the process of shifting our lab and trapping our first ions, but once the new lab is up and running, I’m going to work on implementing this protocol experimentally. Once we’ve done that, we will able to explore various problems in physics that we can interrogate with this protocol such as Hamiltonian quenches, dynamical phase transitions and quantum transport in higher dimensions using 1D chains of ions. As a physicist, it is just fascinating to study these fundamental problems.