The Quantum Advantage
At the end of October, the internet was abuzz with fears and excitement surrounding a major advancement made by Google's quantum computing department. The breakthrough was the achievement of quantum advantage.
So, what is quantum advantage and why does it matter?
Quantum Computing: The Basics
To understand why this matters, we need to first see what quantum computers are, and how they differ from the computers we use every day. "Traditional computers operate using bits, either 0 or 1, and every calculation is built out of combinations of those bits that work together to produce unique sequences," Eli Michaud, a computer science student at AUP pursuing a masters in quantum computing, explains.
By contrast, a quantum computer uses qubits, which obey the unintuitive laws of quantum mechanics. "A qubit has some probability of being either 0 or 1, but it's not either until it's observed. (...) And qubits can be entangled, meaning their states are inseparably linked." Thanks to these effects, quantum computers can, for certain problems, evaluate many possible outcomes “at once,” offering the possibility of dramatic speedups over classical machines, among other things.
Because of that potential, quantum computers have been theorized as tools to solve problems that are impossible for traditional computers: simulating complex molecules, designing new materials, modeling chemical reactions for drug discovery or solving difficult optimization problems. In practice, however, quantum computing has been challenged by practical obstacles: "it's largely an engineering problem," he says.
What did Google do?
That is why it was a huge deal when Google announced that its 105-qubit quantum processor (Willow) had successfully run a new algorithm called Quantum Echoes. According to Google, Willow’s run of Quantum Echoes was roughly 13,000 times faster than the best classical algorithm on one of the world’s fastest supercomputers. The real significance is that this is the first time a quantum computer has demonstrated quantum advantage in "a calculation of any scientific significance."
That being said, what does this algorithm actually do? The details are full of hard-to-understand jargon. "One of the inherent properties of quantum computation is that it's reversible, except for when we measure, and any decoherence (or 'noise')," Eli explains, "Willow takes advantage of this; when a quantum system is perturbed, reversing the calculation reveals an 'echo', how information spreads through the quantum system." According to Google, this could help scientists study complex molecular structures and quantum phenomena in physics that are unreachable for classical simulation.
What makes this important for quantum computing’s future?
For years, a major barrier to running quantum computers has been stability. Qubits are highly sensitive to noise or interference—small fluctuations can collapse the quantum state, ending computations. Keeping the computer cool enough to minimize this noise is one of the most difficult tasks engineers are faced with. Google’s advancement means progress on both qubit fidelity and error rates.
Past successes demonstrated some quantum supremacy, but on narrow, synthetic tasks "whose only purpose is to be impractical on traditional computers and show that quantum computers could do it, but with no evident real-world use," Eli explains, "but these results show that quantum computing might finally be moving in the direction where they can solve practical problems." There are still caveats to be made, however.
Looking to the future
The task Google solved is still fairly specialized. It does not yet mean that quantum computers can routinely solve the kinds of large, messy real-world problems that build headlines and excitement. Fully fault-tolerant, large-scale quantum computers are still a long way off. That said, the October 2025 breakthrough by Google is a major milestone.
Over the coming years, if improvements continue, we might see quantum computing move from lab experiments into practical use. For anyone studying science, engineering or even policy and ethics around technology — paying attention now could mean you’ll see these developments influence the world you work in.
