What is Quantum Computing?

Have you ever wondered what it would be like if a computer could break the rules of reality? If tiny particles could store millions of pieces of data? If computers could think in ways completely different to our laptops and phones? Welcome to the world of quantum computing. 

Regular computers are incredibly powerful, but they have their limits. Some problems, such as simulating molecules for new medicines or modelling complex chemical reactions, are too complex. So, quantum computers use the strange laws of quantum physics to explore problems and possibilities that a regular computer simply can’t handle.

So, what makes these computers so special, and why are scientists so excited about them?

Bits to Qubits

To understand quantum computers, we need to understand how normal computers work. Your computer processes information using bits, tiny switches that can only be 1 or 0s. If we combine millions of them, we can make computers do amazing things, but there’ll still be some problems that even millions of bits can’t solve efficiently.

Quantum computers solve this using qubits. There are two main differences. Firstly, a qubit can be a 0, 1, or both at the same time (superposition). Secondly, two qubits can be linked in a way that changing one will instantly affect the other, even across large distances (entanglement).

Imagine, superposition as a spinning coin. When it spins, it’s not heads or tails, it’s in an ‘in-between state’. For entanglement, picture two magical dice. When one is rolled, the other is automatically rolled too. 

What do they actually do?

Quantum computers are important because they use behaviours that ordinary computers just can’t tap into. A group of qubits can explore many possibilities at once, rather than checking them one by one. When those bits entangle, they share information in a way that lets the system spot patterns that would take much too long with a normal computer. 

This doesn’t make quantum computers better for everyday work. It helps them excel at the hard and complex stuff, like cracking complicated problems that explode in size or searching for patterns in high-grade encryption. These are the sorts of challenges where quantum thinking is needed, which is why researchers around the world are racing to see who can build the most stable and reliable quantum processors. 

The Problem with Qubits?

If qubits are so powerful, then why don’t we all have quantum computers at home? It’s because of decoherence. Qubits tend to be extremely fragile, so even tiny changes in temperature, vibrations or electricity can destroy their state. To keep them stable, quantum computers need:

• Extremely low temperatures (about 0 degrees)

• Extremely clean and controlled environments

• Special shielding to stop interference

You don’t need to be a physicist to realise why this matters. The shift from bits to qubits opens a completely new way to think about information. Even if fully developed quantum computers are years away, the ideology behind them is shaping new research, inspiring new algorithms and allowing scientists to rethink what problems technology can solve. 

Reference List

McKinsey (2025). The Year of Quantum: From concept to reality in 2025. [online] Available at: https://www.mckinsey.com/capabilities/tech-and-ai/our-insights/the-year-of-quantum-from-concept-to-reality-in-2025

IBM (2023). What is a quantum computer? [online] Available at: https://www.ibm.com/think/topics/quantum-computing

Caltech Science Exchange (2022). What Is Quantum Computing? [online] Available at: https://scienceexchange.caltech.edu/topics/quantum-science-explained/quantum-computing-computers

BlueQubit (2023). Breaking Down the Barriers: Quantum Computing Basics Explained! [online] Available at: https://www.bluequbit.io/blog/quantum-computing-basics