The Limit of human technology – Quantum Computers

What Is Quantum Computing?

Quantum computing is a sophisticated approach to making parallel calculations, using the physics that governs subatomic particles to replace the more simplistic transistors in today’s computers.

Quantum computers calculate using qubits, computing units that can be on, off or any value between, instead of the bits in traditional computers that are either on or off, one or zero. The qubit’s ability to live in the in-between state — called superposition — adds a powerful capability to the computing equation, making quantum computers superior for some kinds of math.

How powerful is a quantum computer?

In 200 seconds, the machine performed a mathematically designed calculation so complex that it would take the world’s most powerful supercomputer, IBM’s Summit, 10,000 years to do it. This makes Google’s quantum computer about 158 million times faster than the world’s fastest supercomputer.

What Does a Quantum Computer Do?

Using qubits, quantum computers could buzz through calculations that would take classical computers a loooong time — if they could even finish them.

For example, today’s computers use eight bits to represent any number between 0 and 255. Thanks to features like superposition, a quantum computer can use eight qubits to represent every number between 0 and 255, simultaneously.

It’s a feature like parallelism in computing: All possibilities are computed at once rather than sequentially, providing tremendous speedups.

So, while a classical computer steps through long division calculations one at a time to factor a humongous number, a quantum computer can get the answer in a single step. Boom!

That means quantum computers could reshape whole fields, like cryptography, that are based on factoring what are today impossibly large numbers.

What’s the Outlook for Quantum Computing?

A handful of companies such as Alibaba, Google, Honeywell, IBM, IonQ and Xanadu operate early versions of quantum computers today.

Today they provide tens of qubits. But qubits can be noisy, making them sometimes unreliable. To tackle real-world problems reliably, systems need tens or hundreds of thousands of qubits.

Experts believe it could be a couple decades before we get to a high-fidelity era when quantum computers are truly useful.