Perovskite qubits should not work - but they do, and they cost almost nothing to make

The recipe sounds like it belongs in a kitchen, not a quantum physics lab. Mix chemicals in a beaker. Heat to 480 degrees Celsius. Cool. Add a dash of chromium for color. What comes out is a crystal that looks like a rose-tinted diamond - and it contains functional quantum bits.

Researchers at Linkoping University in Sweden have demonstrated for the first time that perovskite materials can host qubits - the fundamental units of quantum computation. The finding, published in Nature Communications, defies theoretical expectations. Most physicists in the field believed that the atomic interactions within perovskites would be far too strong, causing quantum states to collapse before any useful computation could occur.

Why perovskites were written off

Quantum bits exploit the strange property of superposition: unlike classical bits, which must be either 0 or 1, a qubit can exist in any combination of both states simultaneously. This enables quantum computers to process vastly more information in a given space. But superposition is fragile. Environmental interactions - thermal vibrations, electromagnetic interference, interactions between neighboring atoms - can destroy it, a process called decoherence.

Perovskites have a crystal structure in which atoms interact strongly with each other. That strong coupling should, in theory, cause rapid decoherence - the qubit would lose its quantum properties before completing a calculation. For this reason, the materials were not considered viable candidates for quantum hardware.

The dominant approach to solid-state qubits uses defects in diamond: specifically, nitrogen atoms substituted for carbon in the diamond lattice, creating what are called nitrogen-vacancy (NV) centers. These work well but are expensive and technically demanding to produce, requiring high-energy processes to create precise atomic-scale defects in one of the hardest materials on Earth.

Cooking qubits in a beaker

"That is why we began exploring a new idea - to 'cook up' our qubits in the lab," said Yuttapoom Puttisong, associate professor at Linkoping University.

The process is strikingly simple compared to diamond NV center fabrication. Different chemicals are mixed in solution, heated to 480 degrees Celsius, and cooled to form a perovskite crystal. To create the qubits, chromium is added as a dopant - an active impurity that introduces the necessary electronic states for quantum behavior. The resulting crystal has a rose-like shimmer.

The advantages over diamond are practical: the process is fast, cheap, and controllable. The qubit's properties can be tuned by adjusting the chemistry of the solution rather than relying on high-energy implantation techniques. And because perovskites are fabricated through wet chemistry at relatively modest temperatures, scaling up production is potentially straightforward.

Higher temperatures and optical output

Two additional properties make perovskite qubits interesting. First, they can operate at higher temperatures than superconducting qubits, which require cooling to within thousandths of a degree of absolute zero. While the press release does not specify exactly how warm perovskite qubits can run, avoiding the extreme cryogenic requirements of superconducting systems would substantially reduce the energy, cost, and physical footprint of quantum hardware.

Second, the team demonstrated that qubit signals can be translated into optical signals - pulses of light. This enables quantum communication using photons, a capability that is essential for building quantum networks and could allow perovskite-based systems to interface with existing fiber-optic communication infrastructure.

From crystal to computer: a long gap

Demonstrating that a material can host a qubit is the first step in a long sequence. A functional quantum computer requires not just individual qubits but large arrays of them, connected by precise control and readout systems, with error rates low enough to perform meaningful calculations. The study demonstrates proof of concept - perovskite qubits exist and are measurable - but does not report qubit coherence times, gate fidelities, or error rates, the metrics that determine whether a qubit technology is computationally useful.

The strong atomic interactions that were supposed to prevent perovskite qubits from working have not been fully explained away. The study shows they work despite theoretical objections, but understanding why they work - and what limits their performance - will require further investigation.

"Our findings open up an entirely new research field," Puttisong said. Doctoral student Sakarn Khamkaeo is more specific about the ambition: "In the long term, I believe it could become a natural part of our society in the same way that silicon is today."

That comparison is aspirational. Silicon took decades to go from laboratory curiosity to the backbone of the electronics industry. Perovskite qubits are at the very beginning of that arc. But the cost and simplicity of their fabrication give them a practical advantage that more exotic qubit technologies lack.