BT Explainer: What is quantum computing, why it matters and how India is building it

Quantum computing is poised to revolutionize the way we process information, harnessing the peculiarities of quantum mechanics that govern the smallest particles in the universe. Unlike traditional computers, which operate on predictable binary systems, quantum computers leverage the unique behavior of quantum bits, or qubits, allowing them to tackle complex problems that are beyond the reach of classical machines. The essence of quantum computing lies in its ability to manage information differently. A classical bit can only exist in one of two states—0 or 1. In contrast, a qubit can exist in multiple states simultaneously thanks to a principle known as superposition. This characteristic enables quantum computers to explore numerous potential solutions at once, making them significantly more efficient for certain tasks, such as simulating molecular structures or analyzing vast datasets. Theoretically, this means that problems solvable by today’s fastest supercomputers in thousands of years could potentially be addressed by quantum computers in mere minutes. However, constructing quantum computers poses significant challenges. They are not merely faster versions of classical computers; they necessitate an entirely new hardware paradigm. Most quantum processors must function at temperatures near absolute zero, around -273 degrees Celsius, where materials exhibit different properties, enabling qubits to maintain their quantum states. The complexity of these systems means that even slight disturbances can disrupt computations. Thus, much of the current research in quantum computing is dedicated to enhancing hardware stability and error correction. Quantum computing is not intended to replace classical systems but to complement them, particularly in fields like chemistry and materials science. Quantum systems can perform simulations that aid in drug discovery and innovative material design. Additionally, they have potential applications in optimization, logistics, financial modeling, and energy systems. There is also a burgeoning interest in machine learning, where quantum algorithms could revolutionize the processing of intricate datasets. However, quantum computing also raises significant cybersecurity concerns, as certain quantum algorithms could undermine current encryption methods, making the development of “quantum-safe” security a priority. In a bid to harness the potential of quantum technology, India has launched the National Quantum Mission, which was approved in 2023 with an investment of over Rs 6,000 crore. This initiative aims to establish capabilities in quantum computing, communication, sensing, and materials over the next eight years, aspiring to develop intermediate-scale quantum computers equipped with 50 to 1,000 qubits. A key focus is also on creating secure communication networks using quantum key distribution, recognized for its near-impenetrability. India has already achieved a significant milestone by demonstrating a 1,000-km quantum communication network utilizing indigenous technology. Additionally, India is fostering innovation through its first open-access quantum test beds located in Andhra Pradesh. Part of the Amaravati Quantum Valley initiative, these facilities at SRM University and Medha Towers allow researchers, startups, and students to engage directly with quantum hardware, breaking from the norm of confinement in specialized labs. The modular and accessible design of these facilities is aimed at lowering barriers to entry and accelerating technological advancements. Bengaluru-based QpiAI is leading the charge in quantum hardware development with its launch of “Kaveri,” a 64-qubit superconducting quantum processor, one of India's most powerful quantum systems set to become commercially available soon. Designed for applications in cryptography, optimization, and machine learning, Kaveri aligns with global trends in quantum technology. This follows previous achievements, such as IISc’s six-qubit photonic system, highlighting India's gradual progression in building diverse quantum capabilities. Although quantum computing is still in its infancy, with most systems being experimental and large-scale fault-tolerant quantum computers years away, countries and corporations around the world are heavily investing in this technology, convinced that it will unlock groundbreaking advancements across various industries. For India, the mission transcends merely catching up; it is about fostering a self-reliant ecosystem encompassing hardware, software, talent, and applications.