A Quantum Jump

This month, our columnist provides an overview of Quantum Computing, a paradigm shift in computing with unparalleled speed and power. It is likely to improve our understanding of chemical bonds and chemical reactions and thus pave the way for the development of new drugs, materials, and catalysts. Though its widespread adoption is still a decade away, we need to prepare ourselves to use this disruptive technology.


A Quantum Jump

“When you change the way you look at things; the things you look at change.”
– Max Planck, Father of Quantum Physics.

Among the slew of emerging technologies that promise to disrupt businesses and industries in the decades to come, Quantum Computing is the most mysterious and magical and hence very exciting. It has confounded intellects like Albert Einstein and Bill Gates; the explanation of Quantum Computing borders on the metaphysical. Chemistry and chemical-related sciences are expected to benefit most from the unparalleled power of Quantum Computing. Quantum Computing is expected to enable modeling of systems currently not possible in a conventional computer. These models would be able to accurately simulate chemical bonds and thus aid in the development of new drugs, efficient catalysts and new materials for photovoltaic cells. It would aid us in a deeper understanding of the way enzymes function in photosynthesis and fixing Nitrogen.


Quantum Computing uses qubits instead of bits as the basis of computing. Qubits are superconducting electrons and other subatomic particles, which are manipulated by microwave pulses. Unlike bits that exist in binary states of 1 or 0, qubits exist in a combination of states called “Superposition” and thus hold far more information than bits used in classical computing. The increase in processing power is exponential. Quantum Computing is expected to solve problems that previously eluded solutions due to limitations of computing power. Problems that would have taken hundreds of years to solve on the best supercomputers are expected to be solved in hours and days by quantum computers. These problems are in varied areas like chemistry, materials science, drug discovery, food production, climate change, and traffic management. Quantum Computer is not just faster than a conventional computer; it represents a paradigm shift in computing.

Magical Properties

One of the magical properties of Quantum Computing is “Superposition”, in which a system can exist in more than one state at the same time. A Quantum Computer can represent data as either 1, 0 or both at the same time. Another mystifying feature of Quantum Computing is “Entanglement”, a quantum property which causes two particles to move in perfect sync, no matter how far apart they are physical.

There are 2 approaches to building a Quantum Computer – Trapped Ions and Superconducting Circuits. The Trapped Ions approach involves manipulating quantum information at the atomic level and is the preferred choice of most university research groups. This approach is not easily scalable to industrial levels. Industry start-ups prefer to print the “Quantum System” in Superconducting Circuits.

Quantum Chemistry

One of the first practical uses of Quantum Computing was demonstrated last year by a research team at the University of Sydney, through the simulation of bonds of Lithium Hydride and Hydrogen molecules. Quantum Chemistry is the science of understanding the bonds of molecules and their reactions using quantum mechanics. Modeling chemical processes at the molecular level is beyond the capacity of today’s fastest supercomputers. If these can be modeled using Quantum Computing, it will pave the way to unlock lower energy pathways of chemical reactions and thereby help to develop efficient catalysts. This will have huge benefits for many chemical processes. Experts are unanimous that Quantum Chemistry is emerging as the “killer app” of Quantum Computing.

Bonds and Reactions

Quantum Chemistry is rapidly developing as an interdisciplinary field requiring knowledge of both quantum computation and computational chemistry. Much of computational chemistry is about determining the ground-state energies of molecules, based on which their stability and reactivity can be predicted. The simple Hydrogen molecule was the first to be simulated on Google’s Quantum Computer. Researchers have established the methodology of implementing an algorithm on Quantum Computer that can elucidate a reaction mechanism in order to determine the reaction pathways and calculate the rates. Presently, this is possible only for the simplest of reactions. Over time this has to be extended to study the catalytic action of an organometallic complex or to predict the rate and stability of a drug binding to a protein.

Metal atom clusters, as seen in transition metal catalysis, have the kind of electron structures that lend themselves well to quantum simulation. Breaking of C-H bond for polymerization, CO2 fixing to mitigate climate change and production of Hydrogen for fuel are some of the important reactions that stand to benefit from Quantum Computing. The fixation of atmospheric Nitrogen into Ammonia by the enzyme Nitrogenase is one of the keenly studied reactions in Quantum Chemistry.

Quantum Computers

2019 could very well go down as a milestone in the history of Quantum Computing. In January this year, IBM unveiled the world’s first Quantum Computer for commercial use. It is currently available as a cloud computing service to select customers. IBM, Google, and Microsoft are among the many who are in the race to seize the big opportunity.
Qubits are very sensitive and vulnerable to errors. Today’s Quantum Computer requires an unreasonably large number of iterations to obtain an accurate answer. A fundamental problem in Quantum Computers is the need to provide for an enormous amount of redundancy. A report released last December by the National Academies of Sciences, Engineering and Medicine have some sobering advice on the hype around Quantum Computing. The report cautions that in the near-term, there are no commercially viable applications for Quantum Computing that cannot be handled by conventional computers. Quantum Computing appears at least a decade away from widespread use.


Workforce development is crucial for the growth and advancement of Quantum Computing. Last December, the US Congress passed the National Quantum Initiative Act (NQIA), under which $1.2 billion will be spent over the next 5 years to accelerate investment in quantum information science and to develop a quantum-smart workforce. The National Science Foundation in the USA has created grants to support universities to hire faculty who specialize in quantum sciences. Leading universities in the USA have started offering graduate and undergraduate programmes in Quantum Computing.

“If you want to simulate nature, better make it quantum mechanical”. This 1981 pronouncement of the legendary physicist, Richard Feynman, is more prophetic than ever today.

Readers’ responses may be sent to k.sahasranaman@gmail.com or chemindigest@gmail.com