# Profile

# Mr Farhan Tanvir Chowdhury

## Postgraduate Researcher (Theoretical Physics)

Telephone: **01392 727467**

Extension: **(Streatham) 7467**

**What is my research about? **

My work as a doctoral researcher under Daniel Kattnig & Oleksandr Kyriienko builds on concepts and computational techniques from quantum control theory to refine simulation approaches for studying the dynamics of driven open quantum systems.

**What do I do, and how ****do I do it?**

I simulate the dynamics of electronic and nuclear spin systems numerically, using primarily Python, sometimes Julia. Using establised optimal quantum control methodologies like GRAPE/CRAB, I optimise the reaction products in spin dynamics simulations of radical pair recombination reactions pulsed by radio-frequency (RF) magnetic fields. The latter essentially drives a given quantum spin system to reach a desired target state.

Our initial findings using optimal quantum control to drive radical pair spins in closed quantum systems treatments of their spin dynamics suggest scope for enhancement in their magnetosensitive response to weak magnetic fields. But being able to further extend to more appropriate open quantum systems approaches for modelling the driven dynamics is key to better understanding phenomenon in natural systems subject to a noisy environment and harnessing that understanding to inform design principles for more sensitive quantum magnetometers.

Another key aspect is the need to be able to simulate more physically plausible spin systems with greater number of spins, where we hit computational bottlenecks quickly due to the decreasing tractability in performing spin simulations as the system size grows. In the immediate near term, GPU and parallel computation capabilities are presently the best available tools that could potentially provide some simulation scalability. But for the longer term, harnessing the quantum information processing capabilities of noisy intermediate scale quantum devices could prove crucial for shifting the paradigm in spin simulations.

On the other hand, the fundamental quantum information aspects of many-body quantum physics in large spin systems could provide key insights to better understanding the dynamical behaviour of complex quantum systems. Living systems often manifest noise-assisted quantum effects, where driving the system could be vital for maintaining quantum states in far from equilibria conditions. This is a fundamental requirement for spins to be able to sustain magnetic interactions which are orders of magnitude smaller than thermal energies. Without it, thermal effects would dominate and the system would be restricted to classical behaviour.

**Project Goals**

By formulating optimal quantum control protocols for controlled spin dynamics in quantum complex systems of potential physiological relevance, the goal is to be able to inform experiments to bring about non-classical enhancements in room temperature quantum magnetometry. My work lies at the intersection of fundamental research and the development of computational tools, and producing open-source code for simulating quantum spin dynamics is a primary goal. My preprints and publications so far can be found via Google Scholar.

**Background and other Interests**

In addition to research, I am a postgraduate teaching associate in the Department of Physics. I also remotely teach quantum computing basics and Qiskit to a global cohort of students through QxQ's flagship Intro to Quantum Computing program. I am also an editor/contributor at QuBytes.

Having studied Mathematics and Physics as an undergraduate student at Aberystwyth University, I am fascinated by the connections that fundamental Physics has to diverse areas like Theoretical Computer Science, Abstract Algebra, Mathematical Linguistics, Machine Learning and Complexity Theory. My Erdös Number is 6 (Paul Erdös → Vance Faber → Emanuel Knill → Carlton M. Caves → Animesh Datta → Luke D. Smith → me).

During my masters studies in Mathematical and Theoretical Physics at the University of Sheffield, I remotely worked on a project in Quantum Error Correction, numerically simulating and applying basic QEC protocols on spin chains. I had also looked at the theory of deep generative models, and its links to fundamental Physics, as part of a literature review for a postgraduate taught research training module.

During the pandemic in late 2020, I remotely worked as a research assistant on an ERC climate policy project at the Urban Institute, Sheffield. During sixth form, I was also associated with the Bangladesh Youth Environmental Initiative (BYEI), having assisted in organising the local divisional round for the 2014 International Earth Science Olympiad.

Outside of converting coffee to equations, I like to think of myself as a connoisseur of world literature and a cinéaste, and I occasionally moonlight as a blue-penciler for friends in more artistic circles with literary aspirations.

**Talks and Posters**

- "Quantum Control of Radical Pair Dynamics beyond Time-Local Optimisation"- poster at QuEBS 2023, University of Surrey
- "Spin Chemistry Simulation via Hybrid-Quantum Machine Learning"- poster at IEEE Quantum Week 2022, Colorado
- "Driving spin dynamics with optimal control to enhance quantum effects in the RPM"- poster at QIMP22, TU München
- "From Optimal Control Theory to Quantum Mechanics"- CAPS '19, Swansea University
- "Quantum Walks and Neutrinos"- Particle Physics, String theory and Cosmology (PASCOS) 2019, University of Manchester
- "Undecidability in Mathematics and Physics"- Tomorrow’s Mathematicians Today (TMT) 2019, University of Greenwich

**Spring, Summer and Winter Schools**

- CIQC Winter School on Contemporary Quantum Algorithms and Applications, UCLA, February 2023
- Qalypso Summer School School on Open Quantum Systems, Gozo, September 2022
- IAMP – EMS Summer School in Mathematical Physics, TU München, August 2022
- CIQC Spring School on Open Quantum Systems, March 2022
- 2021 Wolfram Summer School (Fundamental Physics Track)
- 2020 Qiskit Global Summer School on Quantum Computing

**Other Attended Events**

- Participant at NQCC's second "UK Quantum Hackathon", University of Birmingham, July 2023
- Participant at UKRI National Quantum Computing Centre's first "UK Quantum Hackathon", Royal Holloway, July 2022
- Participant at virtual Geometric Representation Theory 2022, Kavli IPMU, University of Tokyo, June 2022
- Participant at virtual Quantum Thermodynamics 2022, Queen's University Belfast, June 2022
- Participant at Mathematics in Life Sciences, University of Exeter, June 2022
- Participant at Quantum Natural Language Processing, University of Oxford, December 2019
- Participant at London Mathematical Society's Prospects in Mathematics Meeting, University of Warwick, September 2018

**Memberships**

- Institute of Physics (IOP), MInstP
- Elected member on the IOP Mathematical and Theoretical Physics special interest group committee
- Association for Computing Machinery (ACM)
- Institute of Electrical and Electronics Engineers (IEEE)

**Other Links: **GitHub, Twitter, Research Gate