No, Quantum Computing Doesn’t “Try Every Possibility at Once”

I’m a developer. My world is one of requests, responses, queues and threads. When I write PHP and Go, I’m often thinking about performance. How can I make this code run faster? How can I handle more requests in the same period of time? These are my (almost) daily questions.

The word “parallel” is music to my ears. It means using multiple cores. It means Promise.all() in JavaScript. It means running my PHPUnit test suite in 16 processes instead of one. It’s a dream of getting more work done in less time. I particularly like this, even more when you know this is something not really doable in PHP when I’m writing these lines.

So, when I first started reading about quantum computing, one phrase jumped out at me: “quantum parallelism.”

I had already learned that a 100-qubit system can represent 2¹⁰⁰ states at once. My next thought was logical.

“Oh. I get it. It runs the same calculation on all 2¹⁰⁰ states at the same time.”

My mind immediately went to a magical place. I pictured an array_map function that could…