D-Wave (QBTS) Stock Drops 5% After a Laptop Challenges Its Quantum Supremacy

TLDR

• QBTS stock fell 5.37% on Tuesday, closing at $27.82, after a two-day rally of nearly 50%
• Researchers at the Flatiron Institute published a study suggesting a classical algorithm can simulate parts of the same problem D-Wave claimed required quantum supremacy
• Some early calculations were reportedly run on a laptop using tensor-network software
• D-Wave pushed back, arguing the new study does not reproduce the full scope of its original Science paper
• Wall Street maintains a Strong Buy consensus on QBTS, with an average price target of $36.11

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D-Wave Quantum pushed back hard this week after researchers claimed a classical computing study had overturned its quantum supremacy result. The market wasn’t waiting around — QBTS dropped 5.37% on Tuesday, closing at $27.82.

D-Wave Quantum Inc., QBTS

The sell-off comes after a sharp two-day run that saw the stock climb nearly 50%. That context matters.

The challenge came from a May 21 paper published in Science by physicists at the Flatiron Institute and Boston University. Their work showed that a classical tensor-network algorithm could simulate parts of the same quantum dynamics problem that D-Wave had used to claim beyond-classical computing performance.

The detail that caught investor attention: researcher Joseph Tindall reportedly ran many of the early calculations on a laptop using a software library called ITensor.

Tindall described tensor networks as “a zip file for the wave function” — a way to compress large quantum problems into a manageable mathematical structure. The implication is that some problems previously considered out of reach for classical computers may not be off-limits after all.

This cuts directly at D-Wave’s March 2025 announcement. The company had claimed its annealing quantum system could simulate quantum dynamics in programmable spin glasses in minutes — a task it said would take nearly a million years on the Frontier supercomputer and consume more energy than the world produces in a year.

D-Wave Fires Back

D-Wave was quick to respond. “The claim that D-Wave’s achievement has been overturned is inaccurate and not supported by the scientific record,” the company said in a statement.

CEO Dr. Alan Baratz acknowledged the Flatiron work as a meaningful advance in classical simulation but argued it falls short of reproducing D-Wave’s full result. He said the researchers did not compute the same observables, did not cover all problem geometries, and did not run the largest or most complex problem sizes tested by D-Wave.

Chief Development Officer Dr. Trevor Lanting backed that up, pointing to separate D-Wave research showing the BP-TNS algorithm fails for strongly coupled three-dimensional spin glasses on cubic and diamond lattices — problems that were central to D-Wave’s original demonstration.

What the Science Actually Shows

The dispute comes down to scope. D-Wave’s original Science paper studied square, cubic, diamond, and biclique topologies. The Flatiron team added large diamond lattice data, which D-Wave says is a partial advance — not a full replication.

D-Wave’s position is that the hardest cases in its study still remain beyond classical reach. The Flatiron work, the company argues, is progress at the edges, not a refutation of the core result.

For investors, the core question is shifting: it’s no longer just whether quantum machines can produce impressive outputs, but whether those outputs can stay ahead of fast-improving classical methods.

Wall Street hasn’t pulled back on QBTS just yet. The stock holds a Strong Buy consensus from 11 analysts — 10 Buys and 1 Hold — with an average price target of $36.11, implying roughly 30% upside from Tuesday’s close.