Quantum computing breakthrough means Google could be very close to revealing revolutionary machine

Google director says computational power is growing at 'doubly exponential' rate

Google is close to realising a practical quantum computer for the first time after making a major discovery with the revolutionary form of computing.

Hartmut Neven, director of Google’s Quantum Artificial Intelligence Lab, revealed to Quanta magazine that his lab’s most advanced quantum processor was improving at a rate far beyond what they had previously thought possible.

The revelation means the tech giant may be just months away from achieving what is known as quantum supremacy, whereby quantum computers are able to solve problems that classical computers practically cannot.

Quantum computers work by replacing traditional bits – the ‘ones’ and ‘zeros’ used in digital communications – with quantum bits, or qubits.

The quantum properties of qubits mean they exist in a state of superposition, meaning the act as both zeros and ones at the same time.

This unusual phenomenon allows quantum computers to be vastly more powerful than traditional computers and means they could potentially solve computing challenges far beyond the reach of the world’s most powerful supercomputers.

It was previously thought that quantum computers were able to make calculations exponentially faster than traditional computers, whereby every qubit added improves the machine’s processing power at an exponential rate.

But computer scientists at Google’s quantum computing lab observed that its systems were gaining power at a “doubly exponential” rate when compared to classical computers.

Quanta magazine described it: “Even exponential growth is pretty fast. It means that some quantity grows by powers of 2: 2¹, 2², 2³, 2⁴. The first few increases might not be that noticeable, but subsequent jumps are massive. Doubly exponential growth is far more dramatic. Instead of increasing by powers of 2, quantities grow by powers of powers of 2: 2²¹,2²²,2²²,2²⁴.”

This rate of development is so unfathomably fast that there is nothing that grows as quickly in the natural world to make a comparison to.

“It looks like nothing is happening, nothing is happening, and then whoops, suddenly you’re in a different world,” the lab’s director Hartmut Neven told Quanta Magazine. “That’s what we’re experiencing here.”