There is this joke about a cat that belonged to a gentleman called Schrdinger: Schrdingers cat walks into a bar. And doesnt."

If you chuckled, you must have been a student of quantum physics. Austrian physicist Erwin Schrdingers Cat Theory is a paradox that explains the seeming contradiction between what we see with our naked eye and what quantum theory says actually is in its microscopic state. He used this to disprove something called the Copenhagen Interpretation" of quantum mechanics. This interpretation states that a particle exists in all states at once until observed". Schrdingers cat is in a box and could be alive or dead. But, till the box is opened, you wont know its state. This would mean that the cat could be both alive and dead at the same time.

Now, hold that thought while we leap from cats to computers. The ones that we use now follow the principles of a Turing machine. Here, information is encoded into bits (either 1s or 0s) and one can apply a series of operations (and, or, not) to those bits to perform any computation. A quantum computer is different, it uses qubits or the quantum analogue of bits. Now, jump back to the cat. Much like the feline in Schrdingers box, a qubit is not always 0 or 1, but can be both at the same time. Only at the end of the computation or when the box is opened, would you know which, but during the computation process, its exact state is indeterminate.

If this leaves you scratching your head, do not fret. In a 2017 Wall Street Journal interview, here is what Bill Gates said: I know a lot of physics and a lot of math. But the one place where they put up slides and it is hieroglyphics, its quantum." Even Einstein had some difficulty grasping the concept and famously dismissed it with, God does not play dice with the universe."

What makes a quantum computer exciting is its ability to exploit these properties of quantum physics to perform certain calculations far more efficiently and faster than any supercomputer. Thus, megacorps such as Microsoft, IBM, and Google have been working on quantum computers. Last week, Google claimed to have achieved quantum supremacy, or the point when such a computer can perform a calculation that a traditional one cannot complete within its lifetime. Googles quantum computer took 200 seconds for a calculation that would take a supercomputer 10,000 years.

While all this is impressive, what does it mean for us? Its hard to fully answer this, as we are venturing into an entirely new area, and the future will reveal applications we have not even imagined yet. Its a bit like classical computing. We did not know how it will totally revolutionize our world. In the same manner, quantum computing could be a game-changer for many industries.

Take big data and analytics. We produce 3 exabits of data every day, equivalent to 300,000 Libraries of Congress. Classical computers are reaching their limits of processing power. However, with exponentially more powerful quantum computers, we could spot unseen patterns in large data sets, integrate data from different data sets, and tackle the whole problem at once. This would be rocket fuel for artificial intelligence (AI), with quantum computing offering quick feedbacks and collapsing the learning curve of machines. This will make AI more intuitive, expand to various industries and help build artificial general intelligence.

Online security will be impacted, with our current data encryption strategies wilting under the assault of quantum power. On the other hand, there will be formidable new cryptographic methods like quantum key distribution, where even if the message gets intercepted, no one can read it (the Cat, again). On a side note, the security of every public blockchain will be under threat from quantum hacks. It was no coincidence that Bitcoins price slumped the day Google announced its breakthrough. Quantum computing could speed up drug development by reviewing multiple molecules simultaneously, quickly sequencing individual DNAs for personalized drugs. Another application lies in weather forecasting and, more importantly, climate-change predictions. It will require the tremendous power of quantum computing to create complex, ever-changing weather models to properly predict and respond to the climate cataclysm that awaits us.

Its a brave new world of quantum computing were entering, and we will discover its possibilities as we go along. If you feel youve got it but are still confused, thats okayit is the nature of this beast. Just step out of the box.

Jaspreet Bindra is a digital transformation and technology expert, and the author of the book The Tech Whisperer

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Opinion | Quantum supremacy and the cat thats neither alive nor dead - Livemint