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Quantum computers process information using qubits that exploit superposition, allowing them to exist as 0, 1, or both simultaneously, unlike classical bits. When multiple qubits are linked through entanglement, their processing power multiplies exponentially, enabling quantum computers to explore vast solution spaces that would take classical computers centuries to solve. However, qubits are fragile and susceptible to decoherence from environmental interference, requiring them to operate at temperatures colder than outer space.
Why it matters
Quantum computing will revolutionize drug discovery by simulating molecular interactions far more efficiently, and simultaneously threatens current encryption systems while promising to create unbreakable quantum encryption. The technology also has transformative potential for artificial intelligence, materials science, and optimization problems affecting supply chains, financial forecasting, and climate modeling.
Imagine a maze with two exits. A classical computer must try one path, hit a dead end, back up, and try the other. A quantum computer explores both simultaneously. This isn’t science fiction—it’s the strange power of quantum mechanics, and it’s about to transform technology as we know it.
The Basic Principle
Classical computers process information using bits—tiny switches that are either 0 or 1, like a light switch that’s either off or on. Quantum computers use quantum bits, or “qubits,” which leverage a bizarre quantum property called superposition. A qubit can exist as 0, 1, or both at the same time until you measure it. It’s like a coin spinning in the air—it’s neither heads nor tails until it lands.
When you link multiple qubits together, their power multiplies exponentially. Two classical bits can represent one of four values at a time (00, 01, 10, or 11). Two qubits can represent all four values simultaneously. With 300 qubits in superposition, you could process more states than there are atoms in the universe.
But there’s a catch: qubits are fragile. They rely on another quantum trick called entanglement, where qubits become mysteriously linked so that measuring one instantly affects the others. They also suffer from “decoherence”—environmental interference causes them to lose their quantum properties. This is why quantum computers must be kept colder than outer space, near absolute zero.
Why It Matters in the Real World
Quantum computers excel at specific problems that would take classical computers centuries to solve. Drug discovery is a prime example: researchers at companies like IBM and startups are using quantum computers to simulate how molecules interact, accelerating the development of new medicines. Classical computers would need to check millions of molecular combinations individually; quantum computers can explore vast solution spaces simultaneously.
Cryptography faces an existential threat—quantum computers could crack the encryption protecting your bank account or medical records. Simultaneously, quantum computers promise to create unbreakable quantum encryption. They’re also poised to revolutionize artificial intelligence, materials science, and optimization problems that affect supply chains, financial forecasting, and climate modeling.
Key Takeaways
- Qubits exploit superposition to exist as 0, 1, or both simultaneously, giving quantum computers exponential processing power over classical systems
- Entanglement links qubits together, but environmental interference causes decoherence, requiring extreme cooling and error correction
- Quantum computing will revolutionize drug discovery, cryptography, and optimization—but only for specific problem types, not all computing tasks
The quantum internet is coming, and it's going to be amazing — Stephanie Wehner →
TED content is used under CC BY-NC-ND 4.0. © TED Conferences, LLC.
Frequently Asked Questions
What is superposition and how does it give quantum computers an advantage over classical computers?
Superposition is a quantum property that allows a qubit to exist as 0, 1, or both simultaneously until measured, unlike classical bits which must be either 0 or 1. This enables quantum computers to process multiple states at once—for example, 300 qubits can represent more states simultaneously than there are atoms in the universe, giving them exponential computational power.
How does entanglement connect qubits and why is it important for quantum computing?
Entanglement is a quantum phenomenon where qubits become mysteriously linked so that measuring one instantly affects the others, allowing them to work in coordinated ways. This interconnection is essential for quantum computers to leverage the exponential power of multiple qubits and perform complex calculations that classical computers cannot.
What is decoherence and why is it a major challenge for quantum computers?
Decoherence occurs when environmental interference causes qubits to lose their quantum properties and collapse from superposition into classical states, disrupting calculations. This is why quantum computers must operate at temperatures colder than outer space, near absolute zero, to minimize environmental disturbances and maintain qubit stability.
Why can two qubits represent four values simultaneously while two classical bits cannot?
Two classical bits can only represent one of four possible values at a time (00, 01, 10, or 11) because each bit must be definitively 0 or 1. Two qubits in superposition can represent all four values at the same time, which is the fundamental advantage that allows quantum computers to explore multiple solutions in parallel.