August 14, 2020

Quantum computing – everything you need to know in 5 minutes

Quantum computing is slowly becoming a more viable source of computing. Google’s recent announcement of reaching the quantum supremacy made major headlines yet also shows how far away we really still are. This article will explore what quantum computing actually is, the potential fields that it will benefit and provide insight into how and when it may affect us all.

What are quantum computers?

Quantum computers are computers that harness the properties of atomic and subatomic principles to increase processing speeds of certain algorithms. The main principles that they harness are superposition and entanglement. Superposition is a phenomenon that mainly applies to light in classical physics, yet in quantum physics also applies to particles. Quantum states can be superposed (added together) and the result will be an equally valid quantum state. Similarly, a quantum state can be represented as a sum of two or more other distinct states. Entanglement is quite different, quantum entanglement is the phenomenon of 2 particles having opposite states, however, unless they are measured both particles exist in both states simultaneously. For example, a bit is either 1 or 0 in classical computing, in quantum computing a qubit (quantum bit) can be either. This therefore produces an exponential number of states (2n) for n qubits. If there were 2 qubits – they could represent 4 states, 3 qubits – 6 states, 10 qubits – 1024 states. When this is coupled with superposition, the bit can be any value between 1 and 0 (more precisely any value within the sphere on the imaginary axis) which allows qubit to perform tasks much much quicker than classical computers.

If qubits are able to be more than 1 state at a time (and even be an infinite number of states), it allows the quantum computer to use an exponential set of states, thereby allowing the computer to solve problems that would take classical computers multiple lifetimes. This allows quantum computers to do something classical computers cannot, quantum computers can do multiple calculations simultaneously due to these phenomena. The best analogy of this is if a computer was asked to find the quickest way around a maze it would try every single branch in turn, until it finds the fastest. A quantum computer would look at all branches simultaneously, thereby reducing computation time exponentially.

This concept is fairly complex but has been hypothesised since the 80s. The most difficult aspect of quantum computing is controlling these qubits. They are extremely hard to create and maintain meaning making a quantum computer required a lot of expertise, trial and error as well as some luck. Additionally, a lot of the materials needed are very rare with few extremely few suppliers. One of the hardest aspects of a quantum computer is keeping the qubits in the ‘unobserved’ state where they can compute using the phenomenon of superposition. Currently the qubits need to be kept as close to absolute zero (-273°C) as possible and are made of superconducting material. This allows the circuit on the chip to behave as single atoms thereby causing the atoms to follow the laws of quantum physics rather than classical physics. Furthermore, the whole setup is suspended via anti vibration brackets to ensure that not even the smallest earthquake/trembling/door slam could disturb the system. This all comes at a tremendous cost which is why the companies closest to solving these problems are some of the world’s largest: Google and IBM.

How close are we?

Well according to Google their quantum computer named Sycamore achieved the quantum supremacy. The quantum supremacy is a calculation that on an ordinary computer would take lifetimes, but on a quantum computer should take orders of magnitude less time. In Google’s case the Sycamores computation took 200 seconds, which is roughly 1 billion times faster than the estimations for a classical computer to complete the same computation (10,000 years). However, IBM argue that the problem that was solved would only take at a maximum 2.5 days, meaning according to them the quantum supremacy has not been reached. This dispute is likely to cause both organisations to push their efforts on further as both want to be seen as the undisputed first to achieve a quantum supremacy.

The problem is Google dispute IBMs dispute. Google have asked IBM to prove the calculation can be done in 2.5 days, however, no proof has been forthcoming. This has caused most people in the computing world to be fairly adamant that Google have achieved something big, however, practically there are many issues standing in the way of quantum computers being commonplace. Firstly, the data from qubits are very noisy, meaning accurate measurements of states is difficult. Furthermore, the junctions in the transistors used to manipulate the qubits are very susceptible to failure, meaning the data from qubits can be lost easily causing error prone results. Google validated their quantum supremacy by running simulations of the calculations on a classical computer as well as theoretical modelling. Once they verified that the system was working, they ran the simulations in conjunction with the quantum computer until classical simulation was no longer feasible. The engineers working on all the major quantum projects are very sceptical of predicting when quantum computers will truly become feasible in today’s world, however, most are optimistic in hoping the revolution will occur in the next 20 years.

What are they actually useful for?

Quantum computing will have a major impact on nearly every major field worldwide. From air traffic control to simulating degradation of Lithium Ion batteries, quantum computers can really revolutionise the world.  Most importantly, perhaps, is encryption.

Public key cryptography is the way the majority of data is encrypted, from secure logins to military traffic, and it relies on RSA encryption. RSA encryption uses factorisation, as multiplying 2 primes together is easy, however finding the factors of a number consisted of 2 primes multiplied together is very difficult. This is the mathematical equivalent of a diode, very easy to go one way, very difficult to go the other. Therefore, if I chose 2 prime numbers p and q, multiply them together I will get pq. Now pq is very difficult to factorise, RSA encryption uses this to create an algorithm which pq can be used to encrypt data, but to decrypt p and q must be known individually thereby allowing anyone to encrypt the data pq (the public key) but only the person with the private key (p and q individually) to decrypt it. This is the basis of RSA encryption which underpins the majority of public key encryption on the internet. The thing is, with quantum computers, prime factorisation is one of the areas which they would be orders of magnitudes faster than classical computers. Thus, when quantum computing does become more reliable and better, RSA encryption will no longer be a viable method.

This does not mean the system will collapse. IBM among others have already started advising some of their clients on methods to “quantum-proof” their data by using specially built algorithms. This means that, by the time quantum computing is able to break RSA encryption, the probability is that not many will be using it anymore.

Another really important area that quantum computers hold a key in is medical research. Currently the pharmaceutical industry uses classical computation to analyse molecules to predict how there could have potentially therapeutic benefits. However, these systems are extremely slow, requiring a lot of time and computation power, it is hypothesised that quantum computing could streamline this process. According to a joint report by Accenture and Biogen, they have “achieved a breakthrough that verified the quantum enabled method for molecular comparison was good or better than existing methods”. This breakthrough holds real hope for the pharmaceutical industry that could (again) revolutionise the industry allowing drugs to be developed faster and more reliably, hopefully reducing costs making the therapies accessible worldwide.

Another important field which quantum technology could transform is material science. From developing new insulating materials to creating superconductors working at room temperature, material science is one of the major fields in the fight against climate change. Developing new materials takes large computation power. Predicting the mechanical properties of polymers in specific circumstances is very difficult. Using quantum computing alongside Artificial Intelligence has the capability to create extremely accurate predictions allowing less trial and error and thereby allowing the streamlining of these processes. If so, this could be another game changer allowing the development of needed materials to occur significantly faster than pre-quantum.

There are countless other industries that quantum computing has the potential of revolutionising. From optimising packing in shipping containers, to accurately predicting weather conditions months away, these are all potential areas quantum computing could have a evident impact on…

Who are the biggest players?

Clearly Google after their Sycamore chipset achieved the quantum supremacy. IBM are seen to be closely behind Google recently building a 53-qubit quantum computer, only just smaller than the 54-qubit Sycamore processor. IBM however have been attempting to try and get a different type of competitive advantage. By launching the IBM Q Experience which has 15 publicly available quantum computers (free to all to use) ranging from 5 to 53 qubits, IBM is attempting to learn from the data it is harvesting about what its clients may want in the future thus allowing them to tailor any designs to future needs.

Governments are also getting in on the action, both the EU and the USA have each committed to investing over $1.1 Billion to support a wide range of quantum technologies. China on the other hand, have committed $15 Billion to quantum computing which will go towards building a state funded dedicated research facility. This in the future could really cause a shift into the world leaders in quantum computing as having a state funded research facility will facilitate access and reduce entry costs for numerous other private and state funded companies. It seems some countries are viewing quantum computing as a private matter while China specifically believe it could help them become the worlds undisputed tech superpower.


In conclusion, it is clear quantum computers are coming. They are the next generation of computing technology which have the power to change countless industries. The power is with you, creating a quantum focus in your business to help guide your company to be able to take full advantage. Educating your staff to understand quantum computing and how it could potentially change your business environment. These are all ways to ensure you stay ahead of the game to take the opportunities that quantum computing will provide…

Sources:,,,,,,,, Accessed [14/08/2020]