How Google's Willow is A Quantum Leap in Computing Tech

Nations and tech giants are investing billions to harness the potential of quantum mechanics for computational tasks previously thought impossible.

This race has intensified as quantum computing moves from theoretical possibility to practical reality, with each advancement bringing us closer to solving complex problems in fields ranging from cryptography and drug discovery to climate modelling and financial analysis.

Amidst this pursuit of quantum computing supremacy, Google has created its latest breakthrough: the Willow quantum chip.

Google's journey in quantum computing, which began over a decade ago, has been marked by several milestone achievements, including their 2019 claim of quantum supremacy with the Sycamore processor.

Willow is the latest evolution in this trajectory, building upon years of research and development at Google Quantum AI, a division that has consistently pushed the boundaries of what's possible in quantum computing.

Unlike previous quantum processors that struggled with error rates and scalability, Willow achieves exponential error reduction and unprecedented computational speed, completing a task in under five minutes that would take one of today’s fastest supercomputers 10 septillion years - a number that vastly exceeds the age of the Universe.

Google’s quantum chip: Willow

Willow’s ability to complete a task in under five minutes sparks a new level of possibility for the global tech industry.

According to Hartmut Neven, Founder and Lead of Google Quantum AI, Willow is instrumental to Google’s advancement in quantum computing: “The Willow chip is a major step on a journey that began over 10 years ago.

“When I founded Google Quantum AI in 2012, the vision was to build a useful, large-scale quantum computer that could harness quantum mechanics — the “operating system” of nature to the extent we know it today — to benefit society by advancing scientific discovery, developing helpful applications and tackling some of society's greatest challenges.

“As part of Google Research, our team has charted a long-term roadmap and Willow moves us significantly along that path towards commercially relevant applications.”

What sets Willow apart from other chips, is that it  demonstrates two key achievements from previous quantum computing efforts.

Firstly, Willow can reduce errors exponentially as it scales up using more qubits, addressing a fundamental challenge in quantum error correction that has persisted for nearly 30 years.

Secondly, Willow’s remarkable performance on a standard benchmark computation.

Exponential quantum error correction: a historic milestone

One of the well known and most significant challenges in quantum computing, has been managing errors that occur due to the fragile nature of qubits, the basic units of quantum information.

Typically, as more qubits are used, more errors occur, potentially causing the system to lose its quantum properties.

However, Google reports that Willow has achieved what is known in the field as "below threshold" performance.

This means that as the number of qubits increases, the error rate decreases exponentially.

The company tested progressively larger arrays of encoded qubits, from a 3x3 grid to a 7x7 grid and found that each increase in size resulted in halving the error rate.

This achievement is particularly notable, as it demonstrates real-time error correction on a superconducting quantum system, a crucial requirement for any useful quantum computation.

It also shows that the arrays of qubits have longer lifetimes than individual physical qubits, indicating that error correction is improving the overall system performance.

Hartmut summarises: “As the first system below threshold, this is the most convincing prototype for a scalable logical qubit built to date. It’s a strong sign that useful, very large quantum computers can indeed be built.

“Willow brings us closer to running practical, commercially-relevant algorithms that can’t be replicated on conventional computers.”

Benchmark performance: quantum supremacy reaffirmed

To measure Willow's performance, Google used the random circuit sampling (RCS) benchmark, a standard test in the field that the company pioneered.

This benchmark is designed to demonstrate a quantum computer's ability to perform tasks that are infeasible for classical computers.

Willow's performance on this benchmark was impressive, as the chip completed a computation in under five minutes that would reportedly take one of today's fastest supercomputers, such as Frontier, an estimated 10 septillion years to complete.

This difference in performance lends credence to the notion that quantum computation occurs in many parallel universes, aligning with the concept of a multiverse.

Hartmut outlines the aim and potential of Willow: “On the one hand, we’ve run the RCS benchmark, which measures performance against classical computers but has no known real-world applications.

“On the other hand, we’ve done scientifically interesting simulations of quantum systems, which have led to new scientific discoveries but are still within the reach of classical computers.

“Our goal is to do both at the same time — to step into the realm of algorithms that are beyond the reach of classical computers and that are useful for real-world, commercially relevant problems.”

Explore the latest edition of Technology Magazine and be part of the conversation at our global conference series, Tech & AI LIVE.

Discover all our upcoming events and secure your tickets today.

Technology Magazine is a BizClik brand