A Quantum Chip Calmed Its Own Chaos, a Step Toward Trustworthy Answers

It started with a bet at a birthday party in 2021. Sriram Ganeshan, a physicist at City College of New York, bet his longtime collaborator, Rutgers physicist Jedediah Pixley, that a puzzling quantum effect had a counterpart in ordinary physics. Pixley lost and paid up in two scoops of blueberry ice cream. The theory that came out of that argument has now been tested on an IBM quantum computer, and the results were published in Nature Physics on October 9, 2026.

The finding is about control. Using a chain of up to 100 qubits on IBM’s 156-qubit Heron processor, the team showed a quantum computer can check parts of itself while it is running and reset them, again and again, until chaotic behavior settles into order. In its largest runs, the paper reports, the processor applied nearly 5,000 operations linking pairs of qubits and nearly 5,000 mid-run checks and resets. Rutgers describes it as among the largest demonstrations to date of this kind of real-time feedback.

Why should anyone outside a physics department care? Because the qubits that make quantum computers powerful are also fragile. Heat, stray signals and tiny hardware flaws nudge them off course, and errors pile up until an answer cannot be trusted. Future machines that keep working despite those mistakes, called fault tolerant, will have to catch and fix problems while a calculation runs. As Pixley put it in the Rutgers release:

“To build a fault-tolerant quantum computer, we have to make these checks and corrections not just once or twice, but a huge number of times during a calculation.” Jedediah Pixley, Rutgers University

The experiment itself is a tug of war, and it is easier to picture than it sounds. One step acts like shuffling a deck of cards, scrambling information across neighboring qubits in a quantum version of a classic chaotic system called the Bernoulli map. The other step checks individual qubits and resets them, pushing the system toward a simple, orderly state the researchers picked. The team dialed how often each step happened. When scrambling ran more than half the time, chaos won. When checking and resetting ran more often, control won. Right around a 50 to 50 split, the whole system flipped at once, a sudden change physicists call a phase transition, like water freezing into ice.

That flip was predicted by theory, and the hardware matched it on systems up to 100 qubits, far beyond the roughly two dozen the team could simulate on conventional computers. Haining Pan, a co-first author, said in the release that the transition became more clearly defined as the systems got larger. Maika Takita of IBM, a senior author, said the experiment shows present-day hardware can coordinate operations, measurements and resets thousands of times across a large system.

A fair caution: this is not full error correction. Steering qubits toward a simple state the researchers picked in advance is a different job from protecting the information a calculation is carrying, and Rutgers notes that a fault-tolerant machine must detect and correct errors without losing the information it carries. The paper itself frames the work as controlling quantum chaos. It is also not brand new: the team posted it as a preprint in September 2025, and peer review has now caught up. Five of the 11 authors work at IBM, which built the processor; the paper declares no competing interests.

Still, the ability to look inside a running quantum computer and act on what is there, thousands of times without the whole thing falling apart, is one of the skills these machines have to master before they can help with the work Rutgers lists: better batteries, cleaner industrial catalysts, and molecules and materials too complex for today’s computers. For the chemists and engineers waiting on that day, an ice cream bet just paid off a little more than anyone expected.