About

I was born and raised in the southern Indian coastal city named Chennai (fondly called Madras). I am currently a postdoctoral research associate with Prof. Bane Vasic at the University of Arizona, Tucson, AZ, USA. I completed my doctoral studies in the Department of Electrical and Computer Engineering at Duke University, Durham, NC, USA, under the supervision of Prof. Henry Pfister and
Prof. Robert Calderbank at the Rhodes Information Initiative at Duke (iiD). My dissertation is here.

Prior to this, I completed my Master of Science (M. S.) degree at Texas A&M University, where I worked with Prof. Henry Pfister on the construction of Cyclic Polar Codes. I was a graduate research intern during the summer of 2015 at Alcatel-Lucent Bell Labs, Stuttgart, Germany, where I worked on the analysis of Spatially-Coupled LDPC ensembles over burst erasure channels, under the supervision of Dr. Laurent Schmalen and Dr. Vahid Aref. My Master’s thesis discusses cyclic polar codes as well as my internship work. Earlier, I completed my Bachelor of Technology (B. Tech.) degree in Electronics and Communication Engineering at Amrita University, Coimbatore, India.

My research interests are in the realms of information and coding theory (both classical and quantum), compressed sensing, and general inference problems. Currently, I am working on the construction of quantum codes and synthesis of their fault-tolerant logical operators for quantum computing. I am also interested in codes and decoding algorithms for quantum communications. I am a Member of the IEEE and the Information Theory Society.

I love pencil sketching and like to read about science, philosophy and life. I play cricket, volleyball and bowling. I am a novice writer and hope to disseminate productive thought and knowledge through this powerful platform called internet. My old blog is here.

This website is powered by Jekyll and this theme is an open source contribution by Panos Sakkos. All suggestions for improving this website are most welcome.

Updates

June 2021: Nature’s npj Quantum Information (npjQI) publishes our paper on a quantum communication advantage using belief propagation with quantum messages (BPQM)! We think this points to a new and exciting application for a small, special-purpose, photonic quantum computer


Mar. 2021: Paper on channel duality between the classical binary symmetric channel (BSC) and the quantum pure-state channel (PSC), targeted primarily at classical information/coding theorists


Dec. 2020: Quantum publishes our paper on unraveling the Clifford hierarchy using Weyl expansions


Nov. 2020: A double blow to the arXiv on the same day! One paper on mitigating coherent noise passively using stabilizer codes, another on approximate unitary 3-designs from transvection Markov chains and Kerdock codes


Sep. 2020: I joined Prof. Bane Vasic’s lab at University of Arizona as a postdoctoral research associate!

IEEE Transactions on Quantum Engineering publishes our Logical Clifford Synthesis (LCS) algorithm MATLAB implementation available open source on GitHub


Aug. 2020: IEEE Transactions on Information Theory publishes our Kerdock Unitary 2-Designs paper


July 2020: Paper connecting robust quantum metrology and classical weight distributions

IEEE Journal on Selected Areas in Information Theory publishes our paper on stabilizer codes that support transversal T; IEEE ISIT publishes the shorter version

Talks at ISIT on classical coding and transversal T and quantum advantage via BPQM


June 2020: Paper on unraveling the Clifford hierarchy using Weyl expansions


May 10, 2020: I have been officially conferred the Doctor of Philosophy (Ph.D.) degree!


March 18, 2020: I successfully defended my Ph.D. in Electrical Engineering at Duke! My dissertation is called Classical Coding Approaches to Quantum Applications and my defense talk is on YouTube!

I turned out to be the first ever student in Duke Engineering to give the Ph.D. defense fully online


Jan. 2020: I gave a talk in Quantum Information Processing (QIP ‘20) about our transversal T work! The video is available online

Shorter paper emphasizing the new classical coding open problem from quantum T gates

Timeline

Publications

A list of my publications is below. You can also follow me on Google Scholar and ResearchGate (which includes unpublished notes and research).

Here is my most recent Curriculum Vitae.

Journal Articles and Preprints

  1. N. Rengaswamy, K. P. Seshadreesan, S. Guha, and H. D. Pfister, “Belief propagation with quantum messages for quantum-enhanced classical communications,” npj Quantum Inf., vol. 7, no. 1, p. 97, Jun. 2021 [Online]. Available at: http://arxiv.org/abs/2003.04356

  2. N. Rengaswamy and H. D. Pfister, “A Semiclassical Proof of Duality Between the Classical BSC and the Quantum PSC,” arXiv preprint arXiv:2103.09225, Mar. 2021 [Online]. Available at:
    http://arxiv.org/abs/2103.09225


  3. T. Pllaha, N. Rengaswamy, O. Tirkkonen, and R. Calderbank, “Un-Weyl-ing the Clifford Hierarchy,” Quantum, vol. 4, p. 370, Dec. 2020 [Online]. Available at: http://arxiv.org/abs/2006.14040

  4. N. Tan, N. Rengaswamy, and R. Calderbank, “Approximate unitary 3-designs from transvection Markov chains,” arXiv preprint arXiv:2011.00128, Nov. 2020 [Online]. Available at: https://arxiv.org/abs/2011.00128

  5. J. Hu, Q. Liang, N. Rengaswamy, and R. Calderbank, “Mitigating Coherent Noise by Balancing Weight-2 Z-Stabilizers,” arXiv preprint arXiv:2011.00197, Nov. 2020 [Online]. Available at:
    https://arxiv.org/abs/2011.00197


  6. N. Rengaswamy, R. Calderbank, S. Kadhe, and H. D. Pfister, “Logical Clifford Synthesis for Stabilizer Codes,” IEEE Trans. Quantum Engg., vol. 1, Sep. 2020 [Online]. Available at: http://arxiv.org/abs/1907.00310

  7. T. Can, N. Rengaswamy, R. Calderbank, and H. D. Pfister, “Kerdock Codes Determine Unitary 2-Designs,” IEEE Trans. Inform. Theory, vol. 66, no. 10, pp. 6104–6120, Aug. 2020 [Online]. Available at:
    http://arxiv.org/abs/1904.07842


  8. N. Rengaswamy, R. Calderbank, M. Newman, and H. D. Pfister, “On Optimality of CSS Codes for Transversal T,” IEEE J. Sel. Areas in Inf. Theory, vol. 1, no. 2, pp. 499–514, Jul. 2020 [Online]. Available at: http://arxiv.org/abs/1910.09333

  9. Y. Ouyang and N. Rengaswamy, “Weight Distribution of Classical Codes Influences Robust Quantum Metrology,” arXiv preprint arXiv:2007.02859, Jul. 2020 [Online]. Available at:
    http://arxiv.org/abs/2007.02859


  10. S. Brandsen, M. Lian, K. D. Stubbs, N. Rengaswamy, and H. D. Pfister, “Adaptive Procedures for Discrimination Between Arbitrary Tensor-Product Quantum States,” arXiv preprint arXiv:1912.05087, Dec. 2019 [Online]. Available at: http://arxiv.org/abs/1912.05087

  11. N. Rengaswamy, R. Calderbank, and H. D. Pfister, “Unifying the Clifford Hierarchy via Symmetric Matrices over Rings,” Phys. Rev. A, vol. 100, no. 2, p. 022304, 2019 [Online]. Available at:
    http://arxiv.org/abs/1902.04022 (or) https://journals.aps.org/pra/abstract/10.1103/PhysRevA.100.022304


  12. V. Aref, N. Rengaswamy, and L. Schmalen, “Finite-Length Analysis of Spatially-Coupled Regular LDPC Ensembles on Burst-Erasure Channels,” IEEE Trans. Inform. Theory, vol. 64, no. 5, pp. 3431–3449, 2018 [Online]. Available at: http://arxiv.org/abs/1611.08267 (or) http://ieeexplore.ieee.org/document/8272426/

  13. N. Rengaswamy, R. Calderbank, S. Kadhe, and H. D. Pfister, “Synthesis of Logical Clifford Operators via Symplectic Geometry,” arXiv preprint arXiv:1803.06987, 2018 [Online]. Available at:
    http://arxiv.org/abs/1803.06987


Conference Articles

  1. N. Rengaswamy, K. P. Seshadreesan, S. Guha, and H. D. Pfister, “Quantum Advantage via Qubit Belief Propagation,” in Proc. IEEE Int. Symp. Inform. Theory, 2020, pp. 1824–1829. Slides

  2. N. Rengaswamy, R. Calderbank, M. Newman, and H. D. Pfister, “Classical Coding Problem from Transversal T Gates,” in Proc. IEEE Int. Symp. Inform. Theory, 2020, pp. 1891–1896 [Online]. Available at:
    http://arxiv.org/abs/2001.04887
    Slides

  3. T. Can, N. Rengaswamy, R. Calderbank, and H. D. Pfister, “Kerdock Codes Determine Unitary 2-Designs,” in Proc. IEEE Int. Symp. Inform. Theory, 2019, pp. 2908–2912. Slides

  4. N. Rengaswamy, R. Calderbank, S. Kadhe, and H. D. Pfister, “Synthesis of Logical Clifford Operators via Symplectic Geometry,” in Proc. IEEE Int. Symp. Inform. Theory, 2018, pp. 791–795. Slides

  5. N. Rengaswamy, L. Schmalen, and V. Aref, “On the Burst Erasure Correctability of Spatially Coupled LDPC Ensembles,” in Proc. IEEE Intl. Zurich Seminar on Commun., 2016, pp. 155–159.

  6. V. Aref, N. Rengaswamy, and L. Schmalen, “Spatially Coupled LDPC Codes Affected by a Single Random Burst of Erasures,” in Proc. Int. Symp. on Turbo Codes & Iterative Inform. Proc., 2016, pp. 166–170.

  7. N. Rengaswamy and H. D. Pfister, “Cyclic Polar Codes,” in Proc. IEEE Int. Symp. Inform. Theory, 2015, pp. 1287–1291. Slides

Theses

  1. N. Rengaswamy, “Classical Coding Approaches to Quantum Applications,” PhD thesis, Duke University, 2020 [Online]. Available at: http://arxiv.org/abs/2004.06834 Slides

  2. N. Rengaswamy, “On Cyclic Polar Codes and the Burst Erasure Performance of Spatially-Coupled LDPC Codes,” Master's thesis, Texas A&M University, 2015
    [Online]. Available at: http://arxiv.org/abs/2004.06875
    Slides

Contact

Drop me an email if you are interested in my work or want to collaborate or to even say hello!