NMR Quantum Information Processing: Indian Contributions and Perspectives

Quantum processors based on NMR architectures, which use nuclear spins as qubits and radio frequency pulses to implement unitary quantum gates, came into existence nearly two decades ago. Since their first proof-of-principle demonstrations as a testbed quantum processors, NMR quantum processors have contributed significantly to advances in various subareas of quantum information processing. Indian researchers have been working in this field since its inception and have continued to contribute to novel developments. This article begins by delineating the basic building blocks of an NMR quantum processor and evaluating the advantages and disadvantages of this quantum technology. Contributions of NMR quantum information processing techniques in the areas of the state initialization and quantum control, experimental implementation of quantum algorithms, entanglement detection and characterization, foundational tests of quantum mechanics, quantum state and process tomography, noise characterization and decoherence mitigation protocols, quantum simulation, and quantum thermodynamics are described. The article traces the historical development of this area, with an emphasis on Indian contributions and perspectives.