Nature India: What is quantum information all about?
Arun Kumar Pati : Information technology is based on classical physics. In today's computers, data is represented in bits – 0s or 1s. Using a quantum system as the information carrier, one can store data in superposition of 0s and 1s (known as qubits) – something like both 1 and 0 at the same time. This allows us to access large number of logical qubits in one go, and process information in parallel, resulting in massive computation beyond the power of supercomputers. QIQC systems can also transmit information that is fundamentally secure and hack-free.
NI : When did research in this field begin?
AKP : The field of QIQC is relatively young having started only in 1985 but is already witnessing tremendous progress. A major driving force in this area is to understand what one can do with quantum features such as superposition and entanglement and what new things one can do as compared to classical information processing devices. A handful of countries are on the forefront having made significant progress in quantum computers, quantum teleportation, super dense coding, remote state preparation, quantum cryptography, and several quantum communication protocols.
NI : What is happening globally in QIQC?
AKP : Government and private companies are significantly invested in developing quantum computers. The European Commission is planning a $1.1 billion investment in quantum research. China, that has already demonstrated world's first video call via quantum-encrypted communications system and longest record breaking quantum teleportation, has committed $10 billion to build world’s biggest quantum research facility in Hefei, Anhui. In the last five years, IBM has invested over $38 billion in new capabilities. Considering the importance of this area, several new Institutes and Centres for Quantum Information have been established all over the world.
NI : How did QIQC research begin in India?
AKP : Many researchers in India were working in the field of quantum mechanics and quantum foundations. Work on QIQC began about three decades back in 1988 after I joined the theoretical physics division of Bhabha Atomic Research Centre (BARC) in Mumbai. Subsequently, other theoreticians from different areas of physics started entering the field. On the experimental side, Anil Kumar's group at the Indian Institute of Science, Bangalore has implemented several algorithms and quantum information protocols since 1999.
NI : What are your major results in quantum information?
AKP : These include no-Deletion principle, Remote State Preparation (RSP), No-Hiding Theorem, Stronger Uncertainty Relations, and very recently no-Masking theorem. The no-Deletion principle, together with no-Cloning principle gives permanence to quantum information, meaning quantum information cannot be created nor destroyed. RSP, of particular importance in quantum communication, is a powerful method to prepare a qubit at a distant location without physically sending the object. The no-Hiding theorem rigorously proves the conservation of quantum information. If quantum information is destroyed from one system, it moves to another system from where it can be recovered. Not only did we prove this but also experimentally tested it in collaboration with Anil Kumar at IISc.
NI : What is the current status of QIQC in India?
AKP : The community has grown over the last 30 years with several young researchers pursuing both theoretical and experimental aspects of QIQC. For example, HRI has the largest group in QI in India and it attracts students and visitors from across the world. Several other active groups are at Indian Institute of Science, Education and Research (IISER), Mohali; Indian Statistical Institute, S N Bose National Centre for Basic Sciences and Bose Institute, Kolkata; Institute of Physics (IOP), Bhubaneswar; Raman Research Institute (RRI) and IISc, Bangalore; Institute of Mathematical Sciences, Chennai; Indian Institute of Information Technology, Hyderabad; and Indian Institute of Technology, Mumbai.
The Department of Science and Technology is planning to start a national programme in Quantum Information Science and Technology. There has to be a significant and sustained investment in quantum information science where academia, industry and government can join hands. Also, the Indian government needs to start an Institute for Quantum Information where physicists, mathematicians, and computer scientists can pursue focused research to achieve the targeted goal in stipulated time frame.
NI : What is the future of QIQC?
AKP : Undoubtedly, the future of Quantum Information is very promising. We can safely say that the future revolution in information technology will be largely based on quantum information science. We have to give importance to both basic and technological applications. We should never forget that `today's basic science is tomorrow's technology'.