Rise of Quantum Computing Chips - Google’s Willow chip

Google has announced that it has achieved a major breakthrough in quantum computing, possibly nudging the technology away from the conceptual towards the practical.

For the first time ever, the tech giant said it has developed a state-of-the-art quantum computing chip called Willow that solved in under five minutes a computation so complex, it would have taken a supercomputer around 10 septillion (10^25) years to complete.

“The Willow chip is a major step on a journey that began over 10 years ago,” Hartmut Neven, the Google executive who founded and leads Quantum AI, the research team behind the breakthrough, said in a blog post on Monday, December

We’ve always hypothesised that quantum computers can do something that classical computers cannot do. That is the main objective of quantum computing, but it has been based on theoretical constructions. If Google’s claims are true, it is a demonstration of that hypothesis to be correct,” Debapriya Basu Roy, an assistant professor in the computer science department of the Indian Institute of Technology (IIT) Kanpur

Let’s take a closer look at the essentials of quantum computing, what exactly Google has achieved with its new Willow chip, and whether it stands to gain an edge in the ongoing AI arms race.

What is quantum computing and qubits?

Everything that is typed into classical computers such as words and numbers get translated into binary code comprising bits with a value of 0 (ground state) or 1 (excited state). However, a qubit leverages the principles of quantum mechanics to exist in both states simultaneously. For instance, a qubit could have a 25% probability of having a value of 0 and a 75% probability of having a value of 1. This means that a single qubit can represent a greater amount of information than a single classical bit.

As a result, quantum computers are able to process information in ways that are impossible for classical computers to do so. They are capable of solving problems that traditional computers cannot.

How are quantum computers different from supercomputers? With advanced architectures and relying on acceleration techniques such as graphic processing units (GPUs) and multi-core processing, classical supercomputers excel at performing calculations at a faster pace. However, they are still bound by the constraints of classical computing principles and depend on logic gates such as AND, OR, XOR, and NOT gates to manipulate classical bits.

Quantum computers, on the other hand, use quantum gates such as H-gate and Pauli gates that are designed to process qubits and are also reversible in nature. “Using these quantum gates, we can develop circuits and algorithms and solve problems that are otherwise impossible to solve,” Roy explained.

What is Google’s quantum computing chip Willow?

Google said that its new state-of-the-art quantum computing chip was fabricated in a facility in Santa Barbara, California, US. The components of the chip include single and two-qubit gates, qubit reset, and readout that have been engineered and integrated to ensure that there is no lag between any two components as that may adversely impact system performance, the company said.

Errors are considered to be one of the greatest challenges in quantum computing as qubits, in superposition, tend to rapidly exchange information with their environment and make it harder to complete a computation. “Typically the more qubits you use, the more errors will occur, and the system becomes classical,” Google said.

However, with Willow, the company said it successfully drove down errors while scaling up the number of qubits processed by a quantum computer.