Quantum computers store and process information using quantum two-level systems (quantum bits or qubits) which follow the laws of quantum physics. Unlike classical bits in conventional digital computersthat can take the values 0 or 1, qubitscan also be prepared in a superposition state which are combinations of 0 and 1. One way to visualize such states is to consider them as all possible points on the surface of our globe. In this model, the north and south pole represent the states 0 and 1 respectively, while all other points are possible superposition states. If this was not strange enough, the quantum laws only allow us to get a binary answer when trying to probe the state of such systems, with the possible answers being 0 (north pole) or 1 (south pole). For different superposition states, the answer is random with the probability of getting a 0 (or 1) being higher if the point on the globe is closer to the north (or south) pole.
Nevertheless, this fundamental ability to create superposition states and entangled states (special superposition states involving multiple qubits) makes quantum computers extremely powerful compared to conventional computers when solving certain kinds of problems. One such example is theShor’s algorithm developed in the 1990s and has important implications for security as it can break RSA encryption, a popular method for secure communication today. In addition, quantum computers can efficiently solve quantum mechanical problems which are otherwise intractable on a conventional computer. Since quantum mechanics is at the heart of most physical, chemical and biological phenomena, a quantum computer promises to revolutionize these fields by enabling us to understand natural processeseffectively and at a fundamental level. This will lead to the discovery of novel materials, clean energy solutions, effective medicines and a deeper understanding of nature.
Several hardware platforms are being pursued today to develop a quantum computer. They include trapped ion qubits, superconducting qubits, semiconducting qubits, photonic qubits, and neutral atom qubits to name a few. All these platforms use different physical systems to isolate two quantum levels for use as a qubit and also differ in how they are controlled and manipulated. While several small-scale quantum processors are now available, including many with free cloud-based access, none of these systems implement quantum error correction (QEC), which is crucial to develop a practical quantum computer.
QEC is required because all qubits are unstable and lose their “quantumness” or quantum coherence in a time ranging from microseconds to seconds depending on the hardware platform. This means that one cannot trust the results of the calculations if they require a runtime comparable to these decoherence times. QEC uses quantum entanglement among several physical qubits to create an effective logical qubit which can be significantly more stable than the constituent physical qubits. While QEC theory is well-developed, and several proof-of-principal experiments have shown promise, practical QEC is a significant milestone that is yet to be achieved.
While the importance of quantum computing (and quantum technologies in general) was clear by the early 2000s, there was very limited activity in India, especially in experimental research with very limited funding.The situation started to improve around 2010 and the past three to five years have seen a significant push in quantum technology research, with many institutions, government agencies, start-ups getting involved and a significant influx of new funds.The Government of India announced a national mission in the Union Budget of 2020with a proposed budget of 8000 crores covering all areas of quantum technologies. It is broadly divided into four verticals: Quantum Computing & Simulations, Quantum Communications, Quantum Sensing & Metrology, and Quantum Material & Devices.
Each of these verticals will be coordinated by a Thematic Hub (T-Hub), which will be set up as a Section 8 company to provide more freedom and flexibility when compared to conventional funding models. The goal of each hub is to coordinate and consolidate all the required activities to achieve the targets set out in the Detailed Project Report (DPR)of the mission. The T-Hub will be awarded to an institute or a consortium based on an open call. All the relevant stakeholders are expected to come together to form a cohesive team to bid for the T-Hubs. In addition, hubs will also carry out translational research, incubate start-ups, create links with industries, foster international collaboration, run an outreach programme and also develop a comprehensive Human Resource Development programme to create the workforce needed to execute this mission.
Since it is not yet clear which hardware platform is likely to yield a practical quantum computer, the mission will focus on key hardware platforms like trapped ion, superconducting, semiconducting, photonic and neutral atom qubits while keeping a close eye on any new emerging platforms. The goal is to develop quantum computers with 50-100 qubits in about 5 years and accelerate to 1000 qubits and beyond in 8 years across several hardware platforms. A strong emphasis will be given to the development ofquantum error correction and quantum algorithms for practical applications relevant to the needs of the country. The mission will also create the ecosystem to enable start-ups to thrive so that they can develop and provide component technologies for quantum computers and also create profitable business cases in the long run.
While ample funding is important, several other things must fall into place to ensure the mission's success. Aggressive hiring of new talent and intensive training programmes in the early part of the mission will be crucial to create a large workforce. In addition, strong coordination with industry to create future opportunities for this workforce will be needed to attract and retain the best talent. Delays in funds disbursal and other impediments like restrictions on import of critical enabling technologies must be removed to enable rapid progress and prevent wastage of time and resources. The mission will generate several indigenously developed technologies but in an increasingly globalized world, a careful balance must be struck between a push for self-reliance and quick access to much needed (and easy available) global resources.With several breakthroughs still needed to make quantum computers practical and useful, the mission should aim to create the right conditions for these breakthroughs to take place in India.
Quantum computing and other quantum technologies are being aggressively pursuedby many countries in the world. The national quantum mission offers a tremendous opportunity for India to contribute significantly in this area with many favourable conditions present currently. With significant implications for healthcare, sustainability, clean energy, climate change,job creation and more, it is clear that the outcomes of this mission will affect the lives of every citizen of the country.However, it will require dedicated teamwork withsmart and efficient execution from all the stakeholders. An optimal mix of basic, applied and translational R&D in conjunction with a continuous and effective evaluation programmewill be needed to keep India relevant in this highly critical area of science and technology and set the stage for taking a leadership position in the 21st century.