To cite this article: M. Jagadesh Kumar, “Quantum Computing in India: An Opportunity that Should Not Be Missed, ” IETE Technical Review, vol.31(3), pp.187-189, May-June 2014.
The laws of quantum physics permit us to process information using what is known as quantum computing. A quantum computer is different from a digital computer that we are so familiar with. While quantum computing sounds like a new technology, the fact is that it is a mathematical approach to finding efficient solutions to computational problems.
Unlike the CMOS integrated circuit technology, which is the backbone of today’s communication revolution, it is difficult to predict the trajectory of future developments in quantum computing. We must remember that the exponential advances in CMOS technology, during the last 60 years, are largely due to the evolution of planar technology based solely on silicon. The historical lesson that we need to learn here is that unless we zero-in on one or two possible technologies using a material whose properties are well understood, the evolution of any technology becomes unpredictable.
Unfortunately, during the last two decades, researchers have been grappling with too many alternate technological approaches (nearly 16 ways) from diverse fields of science to realize quantum computers. Some of these are based on electronic, optical and NMR experimental methods while others draw their strength based on advances in semiconductor and superconductor technologies. Our current inability to make a clear choice from among the available technologies is an indication of our immature status in building a working quantum computer. Unless we narrow down these approaches to a small band of realizable technologies, a quantum computer will only remain as an abstract idea.
To make quantum computing a reality in near future, the following approaches are aggressively studied: Josephson junction circuits, single electron quantum dots, and ion traps. Developments in nanotechnology will, therefore, form the backbone for advancing and realizing quantum computers. In addition, since quantum computing is prone to errors due to imperfections and noise, developing efficient algorithms to take care of quantum error corrections should be an inherent part of any quantum computing initiative. The challenges for the research community, therefore, include creating new models and quantum algorithms, sorting out architectural issues and developing technological solutions if quantum computers are to become a certainty.
From an experimental point of view, there are three areas in which research needs to be focussed: (i) Realizing qubits which are the elementary physical systems of a quantum computer to hold information, (ii) interconnects to pass information from one point to other in the physical platform on which qubits are fabricated and (iii) scaling-up the quantum computing systems. Interconnects in CMOS technology have already become a major roadblock because they cannot be scaled down at the same rate as the transistors. We do not yet know what kind of obstacles will be faced while designing the interconnects for a quantum computer. Qubits are very volatile and can lose the information very fast. This necessitates increasing the computational speed which in turn is affected by how these qubits are interconnected. Much of the research effort now is focussed on realizing the stable qubits on test beds. Broadly, the major research groups in various parts of the world are working on: (i) Superconducting qubits, (ii) flux based qubits, (iii) charge based qubits, and (iv) phase based qubits.
Theories are being developed for scaling and fault tolerant architectures for implementing better quantum algorithms. Other challenging issues for theoreticians include developing models for measurement and control of qubits particularly to minimize the impact of noise and fabrication non-uniformities on the behaviour of qubits. In quantum computing, developing theoretical approaches go hand-in-hand with experimental advances.
There are very few groups working in India in the area of quantum computing. During the last decade, there are less than 100 international journal publications from India on quantum computing. This is less than 2 % of research contribution from India to the world’s research output. Within India, we need to identify groups working in the area of computer algorithms, physics, electronics and materials engineering with interests in quantum computing. It is a highly interdisciplinary area. Computer scientists and mathematicians need to work on algorithms, architectural issues for scalable systems, data storage and data transmission while others will focus on the physical realization of the basic elements of the quantum computers.
Quantum computers can be realized using both top-down approach (based on existing silicon CMOS technology) or bottom-up approach (self-assembly). If we use top-down approaches, we are bound to face the similar road blocks common to highly scaled down silicon technologies. Setting up of such nanoscale fabrication facilities is very expensive running into more than US $ 6 billion. In India, the most cost effective method is to encourage the research groups to focus on bottom-up approaches. This will buoy up a large number of researchers since they can establish the required facilities with moderate cost. Existing expensive nano-research facilities in some of the IITs and IISc should be encouraged to follow the top-down approach to realize practical qubits and their chip level integration.
Some of the important quantum computing research concerns for India in the next ten years, therefore, should be:
1) Develop basic technologies for realizing qubits.
2) Integrate qubits and develop quantum computer test beds by optimizing the architectural issues.
3) Develop quantum algorithms and implement them on quantum computer test beds to demonstrate a proto-type quantum computer that works better than a digital computer.
4) Parallel to this effort, we need to work on issues related to noise, error correction algorithms, data storage and data communication within the quantum computer and between the quantum computers.
In addition, we should also give top priority to the following:
1) Identify the strengths and weaknesses of major research groups working in Josephson junction circuits, single electron quantum dots, and ion traps and set appropriate milestones with sufficient funding. Also encourage groups working with approaches other than the above to realize quantum computers.
2) Encourage theoretical computer scientists and mathematicians to work in close collaboration with experimentalists.
3) Have regular workshops and conferences among the above groups.
4) Establish national level high value fellowships to encourage doctoral and post-doctoral researchers to work in this area.
Developing quantum computational capacity should be India’s “top national priority” simply because acquiring such technologies from outside the country will be too difficult and expensive. The use of quantum computing can lead to many fundamental scientific breakthroughs and new technologies with wide ranging societal and commercial applications such as data encryption, new drug discovery and weather prediction.
In order to keep track of international developments in quantum computing and to assess and steer India’s progress in this area, we need to have an Indian Quantum Computing Roadmap Group (IQCRG) consisting of academicians, industry representatives and end users. Several research groups are working in India within the broad area of Nanotechnology with diffused goals. The benefits of Nanotechnology efforts could be channeled into a specific national goal if these research groups turn their attention to quantum computing putting India on the world map as a significant contributor towards advancing the quantum computing efforts.