Ritajit Majumdar

Ritajit Majumdar

Research Scientist — Quantum Algorithm Engineering Team, IBM Quantum

At IBM Quantum, I work on making quantum computation practical at utility scale, collaborating with academia across algorithms, error mitigation, and quantum-classical workflows.

majumdar.ritajit [at] gmail.com

Making quantum computing practical on today’s noisy hardware.
My recent work centers on error mitigation, noise characterization, and other techniques to make quantum processors reliable. Working with academia, I have applied these to high-energy and condensed-matter physics problems, publishing large-scale demonstrations that push past the limits of classical simulability. Apart from this, resource-aware scheduling and circuit cutting — my other area of study — are converging toward a quantum-centric supercomputing paradigm: QPUs as noise-characterized, schedulable accelerators alongside classical infrastructure, a direction my growing work in combinatorial optimization is now connecting to. During my PhD, I worked on higher-dimensional (qudit) systems, error correction, and circuit optimization.

Research Highlight

Our work on non-Abelian hadron dynamics is the first — and to date only — entry from India on the Quantum Advantage Tracker.

Education

Academic Background

Research

Publications and Patents

arXiv 2026 Quantum Advantage Tracker
Observation of Robust and Coherent Non-Abelian Hadron Dynamics on Noisy Quantum Processors
F. Ilčić, R. Majumdar, E. Mathew, M. O. Ali, N. Earnest-Noble, I. Raychowdhury
arXiv:2602.18080 · First entry from India on the Quantum Advantage Tracker [link] [tracker]
Journal 2026
Lightweight Targeted Estimation of Layout Noise in a Quantum Computer using Quality Indicator Circuits
S. Srivastava, R. Majumdar, P. V. Seshadri, A. Ray, Y. Simmhan
Quantum Information Processing 25, 300 [link]
Journal 2026
Low Overhead Circuit Cutting with Operator Backpropagation
D. Pal, R. Majumdar
Quantum Information Processing 25, 274 [link]
arXiv 2026
Noise-Aware Selection of Circuit Cutting Strategies under Hardware Noise Non-Uniformity
D. Pal, R. Majumdar, P. V. Seshadri, A. Ray, Y. Simmhan
arXiv:2604.24422 [link]
Journal 2025
Krylov diagonalization of large many-body Hamiltonians on a quantum processor
N. Yoshioka, M. Amico, W. Kirby, P. Jurcevic, R. Majumdar, et al.
Nature Communications 16, 5014 [link]
Journal 2024
Efficient Syndrome Decoder for Heavy Hexagonal QECC via Machine Learning
D. Bhoumik, R. Majumdar, D. Madan, D. Vinayagamurthy, S. Raghunathan
ACM Transactions on Quantum Computing 5, 1, Article 5 [link]
Conference 2024
Optimized QAOA Ansatz Circuit Design for Two-Body Hamiltonian Problems
R. Majumdar, D. Madan, D. Bhoumik, D. Vinayagamurthy, S. Raghunathan, et al.
VLSID 2024, pp. 396–401 [link]
US Patent Granted · 2025
Calibrating a Quantum Error Mitigation Technique
D. S. Wang, R. Majumdar, P. Rivero Ramirez
US 12,198,013 [link]
US Patent App. Filed 2024
Quantum Error Mitigation for Probability Distributions
R. Majumdar, P. Rivero Ramirez, S. Majumder, Z. K. Minev
US 2026/0099753 A1 [link]
US Patent App. Filed 2024
Load-Adaptive Circuit Knitting in Quantum Computing Enabled Cloud Environments
R. Majumdar, A. Ray, P. V. Seshadri
US 2025/0384198 A1 [link]
US Patent App. Filed 2024
Learning-Based Quantum Experimental Setup Selection
R. Majumdar, A. Ray, I. Sitdikov, C. Johnson
US 2025/0265484 A1 [link]
US Patent App. Filed 2023
Sparse Noise Tomography-Based Qubit Mapping
R. Majumdar, B. Pokharel, Z. K. Minev, M. Amico
US 2025/0165836 A1 [link]
Outreach

Invited Talks and Tutorials

Tutorials
Hybrid quantum–classical and quantum-centric supercomputing workflows for combinatorial optimization and quantum simulation
R. Majumdar, N. Bronn, S. Raghunathan · HiPC 2026
Finding the sweet spot: balancing error mitigation and circuit simplification for efficient quantum computing
R. Majumdar, K. Shah, A. Eddins, N. Earnest-Noble · IEEE Quantum Week 2026
Operator backpropagation in large scale quantum-classical environments
R. Majumdar, D. Pal, I. Sitdikov, N. Earnest-Noble · IEEE Quantum Week 2025
Algorithms and use-cases for chemistry using quantum-centric supercomputing
R. Majumdar, A. Ray · Supercomputing India 2025
Solving combinatorial optimization on a quantum computer
R. Majumdar, D. Bhoumik, A. Chakrabarti · IEEE International Conference on VLSI Design 2024
Invited Talks
Sample, Don’t Optimize: Quantum Computing’s New Playbook for Molecular Electronic Structure
In-House Symposium 2026 · Department of Chemistry, IIT Bombay
Aug 2026
Diagonalization Beyond Exact Simulation on a Quantum Computer
CQST-FDP-2026 · Centre for Quantum Science and Technology, Siksha ‘O’ Anusandhan University
Aug 2026
Watch →
Making Quantum Computing Practical: Reducing Noise and Overhead
QuCS Lecture 77 · Quantum Computer Systems Lecture Series
Jul 2026
Watch →
Two-Day Lecture Series: Variational Algorithms, Noise in Quantum Hardware, Error Mitigation, and Sample-Based Quantum Diagonalization
QM2C · SRM University, AP
Jun–Jul 2026
Two-Day Workshop on Quantum Computing: From Theory to Practice
With D. Bhoumik · Dept. of Computer Science & Engineering, Birla Institute of Technology, Mesra
Mar 2026
From Quantum Utility to Advantage and Beyond
Susegad Symposium on Quantum Dynamics and Thermalization · BITS Pilani, Goa Campus
Feb 2026
Scaling Circuit Cutting with Operator Backpropagation
Shaastra Fest 2026 · IIT Madras
Jan 2026
Error Mitigation & Careers in Quantum Tech
Qiskit Fall Fest, Day 3 · IISER Kolkata
Oct 2025
Watch →
Quantum Approximate Optimization Algorithm
Qiskit Fall Fest, Day 6 · IIIT Srikakulam, RGUKT-AP
Oct 2025
Watch →
Chemistry Beyond Exact Diagonalization
Sungkyunkwan University, South Korea
Feb 2025
Seminar on the Fundamentals of Quantum Computing
Ramakrishna Mission Vivekananda Educational and Research Institute (RKMVERI)
Sep 2024
Watch →
Fighting Noise on Quantum Devices with Zero Noise Extrapolation
QIQT 2023
May 2023
Watch →
Education

Teaching

Video Lecture Series
Fundamentals
A Mathematical Introduction to Quantum Computing
Watch →
Entanglement
Quantum Entanglement: Superdense Coding, Teleportation and the CHSH Game
Watch →
Algorithms
Grover’s Algorithm
Watch →
Error Mitigation
Expectation Values, Readout Noise and Mitigation
Watch →
Teaching Resources
Code & Tutorials
Quantum Computing Tutorials — Code Repository
View on GitHub →
Guidance

Student Mentorship

For Prospective Interns

Notes from two years of interviewing candidates for the Quantum Algorithm Engineering Team — on the gap between theoretical knowledge and practical, hardware-aware skill that most often separates applicants: Want to intern with the Quantum Algorithm Engineering Team at IBM?

Recognition

Awards & Honors

2022–2025 · NERSC
Director’s Reserve Allocation Award
PI, 50,000 node-hours/year · National Energy Research Scientific Computing Center, U.S. DOE
2021–2022 · USIEF
Fulbright-Nehru Doctoral Research Fellowship
8-month research stay at IBM T. J. Watson Research Center, New York
2017–2018 · DST
DST INSPIRE Scholarship
Department of Science and Technology, Govt. of India
2014–2016 · AICTE
AICTE Scholarship
For pursuing M.Tech · All India Council for Technical Education
Media

Press

Cited in ParliamentPress Information Bureau, Govt. of India
Quantum simulation of the strong nuclear force on a 120-qubit IBM processor — cited in a written reply in the Lok Sabha on the development of quantum algorithms by Indian research institutions
The Hindu
Indian Lab Designs Quantum Algorithm to Beat Classical Computers
Times of India
IBM is at the Forefront of Quantum Computing Tech