By Gokul Siddharthan J, DCMME Graduate Student Assistant

The birth of quantum physics was in the early 20th century, with renowned scientist such as Albert Einstein, Werner Heisenberg making significant contributions in the field. But quantum computing as a discipline emerged only in the 1970s and 1980s. In the 1990s, algorithms were processed faster in quantum computing, leading to an increased interest in the field. Additional discoveries eventually led to a better understanding of how to build real systems that could implement quantum algorithms and correct for errors.

Quantum Computing

We see the benefits of classical computing in our everyday lives. Most of the applications and devices that are ubiquitous in the world today are run on classical computing principles. However, there are limitations that today’s systems will never be able to solve. For challenges above a certain scale and complexity, there isn’t enough computational power on Earth. To stand a chance to solve these complex problems, we need a new kind of computing system that scales exponentially as the complexity grows.

Quantum computing is different from classical computing at a fundamental level. In classical computing, information is processed and stored in bits, 0s and 1s. Millions of bits work together to create the results you see every day. In quantum computing, different physical phenomena are used to manipulate information. These phenomena are superposition, entanglement, and interference. To accomplish this, we rely on different physical devices, quantum bits, or qubits. A qubit is a counterpart to the bit in classical computing. Just as a bit is the basic unit of information in a classical computer, a qubit is the basic unit of information in a quantum computer.

So how is information stored by qubits? A number of elemental particles such as electrons and photons can be used, with either their charge or polarization act as a representation of 0s and 1s. Each of these particles is known as qubits. The nature and behaviour of these particles form the basis of quantum computing. The two most relevant and popular aspects of quantum physics are superposition and entanglement. Superposition is the term used to describe the quantum state where particles can exist in multiple states at the same time and allow quantum computers to look at many different variables at the same time.


The power of quantum computing is unimaginable. A quantum computer comprised of 500 qubits has the potential to do 2^500 calculations in a single step. 2^500 is infinitely more atoms than there are in the known universe. This is true parallel processing. Classical computers today that have so-called parallel processors, still only truly do one thing at a time. There are just two or more of them doing it. Classical computers are better at some tasks than quantum computers such as email, spreadsheets, desktop publishing, etc. The intent of quantum computers is to be a different tool to solve different problems, not to replace classical computers.

Quantum computers are great for solving optimization problems from figuring out the best way to schedule flights at an airport to determine the best delivery routes for the FedEx truck. Google announced it has a quantum computer that is 100 million times faster than any classical computer in its lab. Every day, we produce 2.5 exabytes of data. This is equivalent to the content on 5 million laptops. Quantum computers will make it possible to process the amount of data we’re generating in the age of big data. Rather than use more electricity, quantum computers will reduce power consumption anywhere from 100 to 1000 times because quantum computers use quantum tunnelling. IBM’s computer Deep Blue defeated chess champion Garry Kasparov in 1997. It was able to gain a competitive advantage because it examined 200 million possible moves each second. A quantum machine would be able to calculate 1 trillion moves per second. Google has stated publicly that it will make a viable quantum computer in the next 5 years by launching a 50-qubit quantum computer. Top supercomputers can still manage everything a 5-20 qubit quantum computer can but will be surpassed by a machine with 50 qubits.

Though a viable and true quantum computer is still not a reality, the race is on with many companies offering quantum machines. Quantum computing is no longer in the distant future.