Professor Ramanathan, Ravishankar

PhD National University of Singapore
Assistant Professor

Tel: (+852) 2859 2350
Fax: (+852) 2559 8447
Email: ravi@cs.hku.hk
Research Group Homepage: https://qift.weebly.com/

Dr. Ramanathan's main research interests are in Quantum Cryptography, specifically Randomness Amplification, Expansion and Key Distribution, Device-Independent Applications of Quantum Theory and Foundations of Quantum Mechanics. He has 49 refereed publications in these areas, including 4 papers in Nature Communications, 11 papers in Physical Review Letters, 3 in npj Quantum Information and 5 in Quantum. He received his MSc and PhD in Physics at the National University of Singapore. Before joining HKU, he was a Research Fellow at The National Quantum Information Centre at The University of Gdansk and then a Postdoctoral Researcher at Universite Libre de Bruxelles and University of Oxford.

Research Interests

Quantum Information Theory, Quantum Cryptography, Device-Independent Quantum Information Processing, Foundations of Quantum Mechanics

Selected Publications

• C. Vieira, R. Ramanathan, A. Cabello. Test of the physical significance of Bell non-locality. Nature Communications 16, 4390 (2025).
• R. Ramanathan. Generalised Kochen–Specker theorem for finite non-deterministic outcome assignments. npj Quantum Information 10, 99 (2024).
• Y. Liu, R. Ramanathan, K. Horodecki, M. Rosicka, P. Horodecki. Optimal measurement structures for contextuality applications. npj Quantum Information 9, 63 (2023).
• R. Ramanathan, M. Banacki, R. R. Rodriguez, P. Horodecki. Single trusted qubit is necessary and sufficient for quantum realization of extremal no-signaling correlations. npj Quantum Information 8, 119 (2022).
• R. Ramanathan, M. Rosicka, K. Horodecki, S. Pironio, M. Horodecki, P. Horodecki. Gadget structures in proofs of the Kochen-Specker theorem. Quantum 4, 308 (2020).
• P. Horodecki and R. Ramanathan. The relativistic causality versus no-signaling paradigm for multi-party correlations. Nature Communications 10, 1701 (2019).
• R. Ramanathan, D. Goyeneche, S. Muhammad, P. Mironowicz, M. Grunfeld, M. Bourennane and P. Horodecki. Steering is an essential feature of non-locality in quantum theory, Nature Communications 9, 4244 (2018).
• H. Wojewodka, F. G. S. L. Brandao, A. Grudka, M. Horodecki, K. Horodecki, P. Horodecki, M. Pawlowski, R. Ramanathan, M. Stankiewicz. Amplifying the randomness of weak sources correlated with devices. IEEE Transactions on Information Theory, vol. 63, no. 11, 7592 (2017).
• F. G. S. L. Brandao, R. Ramanathan, A. Grudka, K. Horodecki, M. Horodecki, P. Horodecki, T. Szarek, H. Wojewodka. Realistic noise-tolerant randomness amplification using finite number of devices. Nature Communications 7, 11345 (2016).
• R. Ramanathan, J. Tuziemski, M. Horodecki and P. Horodecki. No Quantum Realization of Extremal No-Signaling Boxes, Physical Review Letters 117, 050401 (2016).
• R. Ramanathan, F. Brandao, K. Horodecki, M. Horodecki, P. Horodecki, H. Wojewodka. Randomness amplification against no-signaling adversaries using two devices. Physical Review Letters 117, 230501 (2016).
• R. Ramanathan and P. Horodecki. Necessary and Sufficient Condition for State-Independent Contextual Measurement Scenarios, Physical Review Letters 112, 040404 (2014).
• R. Ramanathan, A. Kay, G. Murta, P. Horodecki. Characterising the Performance of XOR Games and the Shannon Capacity of Graphs. Physical Review Letters 113, 240401 (2014).
• R. Ramanathan and P. Horodecki. Strong monogamies of no-signaling violations for bipartite correlation Bell inequalities. Physical Review Letters 113, 210403 (2014).