This year’s physics Nobel Prize went to pioneers in quantum tech. Here’s how their work could change the world.A brief guide to the weird and revolutionary world of quantum computers.
Bryan Walsh
4 October 2022
Vox//Classic computing power increases linearly with the addition of each transistor, but a quantum computer’s power increases exponentially with the addition of each new reliable qubit. That’s because of another quantum mechanical property called "
entanglement," whereby the individual probabilities of each qubit can be affected by the other qubits in the system.
All of which means that the upper limit of a workable quantum computer’s power far exceeds what would be possible in classic computing.
So quantum computers could theoretically solve problems that a classic computer, no matter how powerful, never could.//
//On the security side, quantum computers could break cryptography methods, potentially rendering everything from emails to financial data to national secrets insecure — which is why the race for quantum supremacy is also an international competition, one that the Chinese government is pouring billions into.//
//Inside the Watson building, Jerry Chow — who directs IBM’s experimental quantum computer center — opened a 9-foot glass cube to show me something that looked like a chandelier made out of gold: IBM’s Quantum System One. Much of the chandelier is essentially a high-tech fridge, with coils that carry superfluids capable of cooling the hardware to 100th of a degree Celsius above absolute zero — colder, Chow told me, than outer space.
Refrigeration is key to making IBM’s quantum computers work, and it also demonstrates why doing so is such an engineering challenge. While quantum computers are potentially far more powerful than their classic counterparts, they’re also far, far more finicky.
Remember what I said about the quantum properties of superposition and entanglement? While qubits can do things a mere bit could never dream of, the slightest variation in temperature or noise or radiation can cause them to lose those properties through something called
decoherence.
That fancy refrigeration is designed to keep the system’s qubits from decohering before the computer has completed its calculations. The very earliest superconducting qubits lost coherence in less than a nanosecond, while today IBM’s most advanced quantum computers can maintain coherence for as many as 400 microseconds. (Each second contains 1 million microseconds.)//
Locked
