Quantum Computing: The Future
By: Gaurav Lohkna
Tags: IBM, Quantum Computing, Future, Cryptography, Computer Science

Contributor: Gaurav Lohkna

As we have observed, computer technology is exhilarating a radical transformation in our society from an industrial economy to an information economy. Code-driven systems have spread to more than half of the world’s inhabitants in ambient information and connectivity, offering previously unimagined opportunities to them.

Let us understand computation from the very beginning with an electrical computer ENIAC, 1946, being the first electrical and programmable computer that could perform 10 Kilo instructions per second(KIPS) with a memory space of 2 KiloBytes (KB) and occupying a basement of size 50x30 feet. With more than 17,000 vacuum tubes, 70,000 resistors, 10,000 capacitors, 6,000 switches, and 1,500 relays, it was easily the most complex electronic system theretofore built. It was a mammoth, producing 174 Kilowatts of heat and performing up to 5000 additions per second, which was several orders of magnitude faster than its electromechanical predecessors.

And today, here we are with much more powerful computers that have multi-core GHz processors and can process more than 100 billion instructions per second and we can fit them in our pockets while using them for everyday lifestyle. Put simply, the iPhone 6’s clock is 32,600 times faster than the best Apollo era computers(1960) and could perform instructions 120,000,000 times faster. Awestruck?

Now, you might be wondering how did we achieve all this computational power? So the answer is, the smaller the processors we made the faster the computers processed. According to Moore’s law, “the numbers of transistors in a dense integrated circuit double about every two years and hence the processing power increases”. However, Moore’s law is slowing down, meaning that decades’ worth of endless enhancements in computing power is coming to an end as it gets more expensive to create even smaller silicon-based transistors for computer chips. Still, researchers all around the world have found ways to push the limits of transistors so much that today we have 5nm, 3nm, 1nm, 0.5nm, and even single-atom transistors in the labs of researchers.

But recently, we have dared the laws of physics by creating a transistor of 0 nm, yes you read it correctly— 0 nm. Scientists have created a single-photon transistor that has a non-existent dimension.

With this much smaller transistors we might be able to achieve super-computer processing power in our smartphones in near future but the question that arises is, are supercomputers that really fast as they seem?

For some problems, supercomputers are not that super. Until now, we’ve relied on supercomputers to solve most problems. These are very large classical computers, often with thousands of classical CPU and GPU cores. However, supercomputers aren’t very good at solving certain types of problems, which seem simple at first sight.

This is why we need a whole new concept of computing: quantum computing. Quantum computers harness the phenomena of quantum mechanics to achieve a huge leap forward in computation to solve certain complex problems that today’s most powerful supercomputers cannot solve, and never will.

Now let us take a simple and classical problem of computation to understand the computational power of a supercomputer and quantum computer. Imagine you want to seat a few fussy people at a dinner party, where there is only one optimal seating plan out of all the different possible combinations. How many different combinations would you have to explore to find the optimal?

For 2 people there would be 2 combinations, for 3 people there would be 6 combinations. Can you guess how many combinations would be there for 10 fussy people? There would be more than 3 million combinations, to be exact 3,650,000 combinations. Surprised?

And what if you have to make a seating arrangement for 100 of such people? You would be requiring a supercomputer to determine the seating arrangement plan and it would be around 9.34 x 10^157 (157 zeros after 9.34) combinations which might take several days to compute. Saying it in a sarcastic way the guests would die of hunger if they have to wait for the seating arrangement plan. Here comes the quantum computer to save the guests from dying of starvation which can calculate it within seconds. Amazing, right?

Let me try to tell you in a layperson’s way of understanding about the comparison between the speeds of two. Suppose you wanted to find a person from a line of 1 trillion people (1,000,000,000,000 people), and each person took 1 microsecond to check (which is really-really fast) then a classical computer will take around 1 week to find that person and a quantum computer will take around 1 second only.

This wild beast, IBM Q, currently about the size of a household fridge, with an accompanying wardrobe-sized box of electronics, designed by IBM can create vast multidimensional spaces in which to represent these very large problems. Classical supercomputers cannot do this. Algorithms that employ quantum wave interference are then used to find solutions in this space and translate them back into forms we can use and understand.

A quantum computer uses quantum bits or qubits rather than using binary bits ( 0 or 1). A qubit itself isn’t very useful. However, by creating many qubits and connecting them in a state called superposition we can create vast computational spaces. We then represent complex problems in this space using programmable gates. These quantum bits behave randomly and to use their computational power we need entanglement, quantum entanglement enables qubits to be perfectly correlated with each other. Using quantum algorithms that utilize quantum entanglement, specific complex problems can be solved more efficiently than on classical computers.

Quantum computing is an exceptionally powerful computational tool and with this much power, we can enhance our human civilization. There is a broad spectrum of possibilities in which we can use the quantum computer. I am going to discuss some of the primary applications of quantum computers.

Molecular Modeling

One of the topics that thrill me the most is molecular level biology of some of the most famous drugs that are used to treat cancer in different type of protein cells. We can design a molecular model for every protein cell and how it is getting affected by the drug interaction because chemical reactions are quantum in nature as they form highly entangled quantum superposition states.

Weather Forecasting

Directly or indirectly, the world’s 30% of GDP is affected by the weather and its forecasting. Currently, we use classical computers to predict the weather but it is not that efficient and it might take longer than it takes the actual weather to develop. In weather forecasting, there are billions of billions variables which are dependent on each other and it gets really complex for a classical computer to predict it but a quantum computer’s basic ability is to perform exponentially large calculations parallelly and reducing the time and labor. With this, we might be able to produce better crops, save people from natural calamities, and even foretell the effect of humans on the environment in a long run.

Cryptography

Almost every online transaction’s security depends on the difficulty of factoring large numbers into primes. A classical computer can do this work but again it will take an exponential amount of time to factorize but a quantum computer can do this work in a fraction of time and thus making prime factorization cryptography out-of-date. Hence, we are going to need new and complex cryptographies to protect the internet.