Quantum computing has been described as revolutionary so many times that the word has lost almost all meaning. And yet — the reality of what is happening in quantum research labs right now genuinely is remarkable, and the implications for encryption, medicine, climate modelling and AI are real and significant.
What Is a Quantum Computer, Really?
A regular computer works using bits. A bit is the most basic unit of information. It can be either 0 or 1. Every calculation your computer performs is ultimately represented as a sequence of 0s and 1s.
A quantum computer works differently. Instead of bits, it uses qubits (quantum bits). Thanks to a quantum property called superposition, a qubit can be 0, 1, or both at the same time — until you measure it, at which point it “collapses” to one definite state.
“A quantum computer with 300 qubits could explore more states simultaneously than there are atoms in the observable universe.” — IBM Quantum Research
The Second Key Concept: Entanglement
When two qubits are entangled, the state of one is instantly correlated with the state of the other — no matter how far apart they are. This allows quantum computers to coordinate calculations across qubits in a way that has no equivalent in classical computing.
Where Are We Actually Right Now?
- IBM has built quantum processors with over 1,000 qubits and has a roadmap to reach 100,000 qubits by the end of the decade.
- Google claimed “quantum supremacy” in 2019 with a 53-qubit processor that performed a calculation in 200 seconds that would take a classical supercomputer 10,000 years.
- Microsoft has taken a different approach, focusing on “topological qubits” which are theoretically more stable.
- IonQ, Rigetti, and a dozen other startups are pursuing different hardware approaches and raising significant capital.
What Will Quantum Computing Actually Change?
Drug Discovery and Materials Science
Designing new molecules is extraordinarily computationally intensive. Quantum computers can simulate molecular behaviour directly. This could dramatically accelerate the development of new drugs, new battery chemistries, new fertilisers and new materials.
Cryptography: The Most Urgent Concern
Most of the encryption that secures the internet is based on the difficulty of factoring very large numbers. For a sufficiently powerful quantum computer running Shor’s algorithm, it could become trivially easy. This is why NIST published its first approved post-quantum cryptography algorithms in 2024.
Optimisation Problems
Logistics, supply chain routing, financial portfolio optimisation, traffic management — these are all problems where you need to find the best solution among billions of possibilities. Quantum computing offers a potential path to much better solutions.
AI and Machine Learning
There is significant research into quantum machine learning — using quantum processors to speed up certain parts of AI training and inference. This remains early and speculative, but it is one of the most active research areas in both fields.