Technology as we know it is limited by the fact that the computers of our time do not have adequate processing power to solve the most challenging problems that we have to offer. Computers that we use in our day-to-day lives are based on conventional computing; computer chips contain transistors, which can either be in an on or off state, similar to a light switch. Essentially, computers are a vast collection of switches, each in one of two states. These states are represented in binary, with 0 representing the off state and 1 representing the on state. To put it simply, binary is the “language” that a computer can “understand,” and it is the only one that a computer can communicate in. The key issue with this system is that it is slow, or rather that it can be slow when faced with a particularly difficult problem, which is where quantum computers come in.

Quantum superposition

Quantum physics has demonstrated that it is possible for a quantum system to be in two different states at once until it is measured. This phenomenon is known as quantum superposition and occurs in photons, which are quanta of the electromagnetic field (a quantum is the minimum amount of any physical entity involved in an interaction). Schrödinger’s cat provides a simplified example of quantum superposition: a cat is placed in a box with an object that can kill it, and then the box is sealed. Until the box is opened, you can’t know if the cat is alive or dead. Therefore, while the cat is not observed, it is both alive and dead simultaneously. A quantum computer works on this basis, using qubits rather than bits. Whilst bits can only be in an on or off state (1 or 0), qubits can be in a state of quantum superposition, meaning that, whilst they can still be on or off, they can also be both on and off simultaneously, or somewhere between the two.

Quantum interference and entanglement

Superposition allows quantum algorithms to utilise other quantum mechanical phenomena, such as interference and entanglement. Qubit states can experience quantum interference as each qubit has a probability amplitude describing its position, and these probabilistic superposition states allow qubits to interact with each other. Quantum entanglement occurs when two systems are so strongly correlated that information gained about one can give immediate information about the other, no matter the distance between the two systems. Changing the state of an entangled qubit will immediately change the state of the paired qubit, meaning immense speed of processing in quantum computers. Together, superposition, interference, and entanglement create computing power that can solve problems exponentially faster than classical computers, as quantum computers are exponentially more complex: to simulate a quantum system of n qubits, you’d need to have 2^n bits. Therefore, for a system of 50 qubits, 2^50 bits would be needed, which is over 1 quadrillion bits (about 250 terabytes).

Quantum computing in Finance

This immensely powerful technology is predicted to have applications in hundreds of different fields, one of which is the finance sector. Financial modelling is used to simulate decisions on conventional computers (Monte Carlo simulation), taking into account risk, potential returns, and more. These simulations are run continuously, consuming an enormous amount of computer time. By utilising quantum technology in these simulations, companies can not only improve the quality of the solutions they reach but also reduce the time it takes to develop them. Companies that run these simulations will be handling billions of pounds at a time, so even minuscule improvements in efficiency will lead to a large increase in returns. Furthermore, quantum technology can be used to optimise trading: with conventional computers, investment managers struggle to incorporate real-life constraints, like market volatility and customer life-event changes, into portfolio optimisations. Quantum technology will allow money managers to simulate scenarios and investment options in order to calculate expected returns from different actions, cutting through the complexity of modern trading environments. This would allow investment managers to improve portfolio diversification and ensure investments more precisely respond to current market conditions and the goals of investors.

Quantum computing and AI

Quantum computing will also have wider applications in the field of computer science—for example, in artificial intelligence. Machine learning models require thorough training, which is a very long process. Quantum computers are able to process huge amounts of information when compared to classical computers, so they can speed up this training process as AI can be trained from larger and more complex data sets. Quantum computing can also allow AI to break through language barriers, meaning AI no longer needs to be retrained before being able to function in other languages. This makes the prospect of global AI all the more feasible. As they both continue to develop, AI and quantum computers will work in conjunction, each facilitating the other’s development as we move towards the future of technology.

Looking to the future

So, how long can we expect to wait until this technology is readily available? It is estimated that there could be 2–5000 quantum computers in the world by 2030. Hardware for quantum computers has to be very specific, as qubits are prone to errors. Environmental changes (thermal fluctuations, electromagnetic radiation, magnetic fields) can knock a qubit out of its intended state, causing degradation of information; this is known as decoherence. Quantum computers can be refrigerated to reduce the risk of thermal fluctuations, but decoherence can still eventually creep in. On February 23, 2023, Google reached a major milestone in the development of quantum computers, reducing errors in calculations while increasing the number of physical qubits in a logical qubit (groups of physical qubits working together to perform a computation). The largest and most powerful technology companies are actively researching and developing this technology, and progress is continuous. Whilst there are many challenges involved in its development, and we may be unsure of how long it will be until it is readily available, one thing is clear: the future of quantum computing is profoundly exciting, and will, in my opinion, be worth the wait.