Scan any tech headline lately and one phrase keeps surfacing: quantum computing. NVIDIA's Jensen Huang talks about it, and Google, IBM, and Microsoft are pouring astronomical sums into it. Why?
If your mental model is "a computer, but much faster," you're missing the interesting part. Korean physicist Beomjun Kim, one of the country's best-known science communicators, has a set of wonderfully intuitive explanations for what this technology actually is and why it's different in kind, not just in degree. Here they are, no math degree required.
1. Regular Computers vs GPUs vs Quantum Computers
The machine you're reading this on and a quantum computer differ in how they process information, not just in how fast they do it.
| How It Computes | How It Scales | |
|---|---|---|
| Regular computer (PC, smartphone) | Reads voltage as 0 or 1; information arrives in one long line, processed one step at a time | Faster chips, but still sequential |
| GPU | Processes many lines at once (parallel processing), like opening 100 ticket windows so 100 people can buy tickets at the same time | To double speed, double the cores: 100 → 200 windows |
| Quantum computer | Computes with qubits, which can be 0 and 1 at the same time (superposition) and link tightly to each other (entanglement) | Add one qubit and capacity doubles, so growth is exponential |
That last row is the whole story. A regular processor needs hundreds of extra cores to double its throughput, while a quantum computer gets there by adding a single qubit. Grow a 100-qubit machine to 200 qubits and the capacity multiplies by 2100, roughly a 1 followed by 30 zeros. No amount of extra GPU cores gets you anywhere near that.
2. The Best Analogy: A Maze and the Art of Cloning
Professor Kim's most vivid illustration of quantum speed is a maze.
A regular computer solves a maze the honest way: at every fork it picks one path, follows it to the end, backtracks when it hits a dead end, and tries the next one. Diligent, reliable, and slow.
A quantum computer does something that sounds like a fantasy novel: at every fork, it clones itself and walks the left path and the right path at the same time. It isn't flickering back and forth between them. It genuinely explores every route at once, splitting again at each new fork, until all paths have been walked.
There's one catch, and it's the strangest part: you cannot peek while it's working. Mid-computation, the system is like Schrödinger's famous cat in its sealed box: a blur of possibilities that collapses if observed. Only at the final step, when you "open the box" (in physics terms, take a measurement), do you get your answer: a single, definite route out of the maze.
3. Will Quantum Computers Crack Bitcoin and Bank Encryption?
This is the question everyone asks next. Today's standard encryption, the system protecting your bank account, your messages, and your crypto wallet, rests on one convenient mathematical fact: multiplying is easy, but un-multiplying is brutally hard.
Multiply the primes 17 and 31 and you get 527 instantly. But hand someone just the 527 and ask which two primes produced it, and they have to grind through trial and error. Scale that up to numbers hundreds of digits long, and even supercomputers would need longer than the age of the universe. That asymmetry is modern security.
The unsettling part: an algorithm that lets quantum computers tear through exactly this factoring problem already exists. So is the future of online security doomed?
Professor Kim's answer: don't lose sleep over it. The security industry saw this coming and is already rolling out post-quantum cryptography (PQC), encryption designed to withstand quantum attacks. There's even a twist in the other direction. Because observing a quantum state changes it, an eavesdropper on a quantum-secured channel exposes themselves the instant they peek, which could make future systems safer than what we have today.
4. The Secret of the Golden Chandelier
If you've seen photos of Google's or IBM's quantum computers, you know they look like ornate golden chandeliers from a grand hotel lobby. What the photos don't tell you: 99% of that glittering structure is a refrigerator.
Today's leading quantum computers use superconducting circuits, and their qubits are almost comically fragile. A single stray particle or a whisper of heat destroys the quantum state (physicists call this decoherence). To shield the computation, the hardware must be chilled to nearly absolute zero, around −273°C, colder than outer space.
The actual computer, the chip doing the maze-running and code-breaking, is a palm-sized device mounted at the very bottom of the chandelier. Everything above it exists to keep that little chip in the coldest, quietest place humans can engineer.
5. The Next 10 Years: The Quantum 2.0 Era
There's a running joke in physics: thirty years ago, experts said practical quantum computers were "30 years away." Twenty years ago, the answer was still "30 years away." The horizon never seemed to get closer.
That has changed. Scientists in the field now talk about "within 10 years," and the center of gravity has shifted from pure physics departments to engineering teams and major corporations solving concrete application problems. When the builders replace the theorists, commercialization is no longer hypothetical.
Early quantum computers won't be general-purpose machines like your smartphone. They'll specialize in optimization problems, the "find the best combination among astronomically many" tasks that choke classical computers:
- Drug and materials discovery: simulating huge numbers of molecular combinations to find the most effective one, in simulation instead of years of lab trials
- Logistics and traffic routing: optimizing delivery networks and transport flows across millions of variables
- AI plus quantum: pairing quantum computers with AI models, two fast-moving technologies that could compound each other (AI is already reshaping everyday work on its own)
Physicists call the 20th century the "Quantum 1.0" era: quantum knowledge gave us semiconductors and LEDs, but the devices themselves still ran on classical physics. In Quantum 2.0, the device's operation is quantum mechanics. The race is global, and South Korea, with its semiconductor fabrication and algorithm talent, is a serious contender alongside the US and China.
Frequently Asked Questions
Will a quantum computer replace my laptop?
No, and it isn't trying to. Quantum computers are specialists for optimization and simulation problems, not general-purpose machines. For email and spreadsheets, your laptop is already the right tool.
Is my banking or crypto actually at risk?
Not imminently. Large-scale code-breaking quantum computers don't exist yet, and the migration to post-quantum cryptography is already underway precisely so the locks change before the lockpicks arrive.
Why does a quantum computer need to be so cold?
Qubits lose their quantum state the moment they interact with heat or stray particles. Near absolute zero, the environment goes quiet enough for the fragile superposition to survive long enough to compute.
When will ordinary people feel the impact?
Probably indirectly, and within the coming decade: a drug discovered faster, a cheaper battery, a delivery that shows up sooner. A quantum gadget on your desk is not the plan.
Final Thoughts
Quantum computing sounds like science fiction, yet it's being built and funded in real buildings right now. You don't need to understand superposition mathematically; the maze and the clones will carry you surprisingly far.
The shift worth registering is from machines that check one path at a time to machines that walk them all at once. The last time the rules of computing changed this deeply, we got the digital world we live in today. It's worth paying attention to what we get next.
"Nature isn't classical, dammit, and if you want to make a simulation of nature, you'd better make it quantum mechanical." — Richard Feynman
Emma is a certified wellness coach and the founder of The Daily Glow. She writes weekly about intentional living and the everyday habits that actually stick. Read her story →
