In the lab, Oxford holds quantum entanglement for 10 seconds

In a laboratory at the University of Oxford, four atoms now share a single quantum state, and it survives for 10 seconds. Strontium and calcium atoms sit in two different locations. The sources present it as a record entanglement time that paves the way for longer links between atoms.

A quantum computer works with qubits, units that can take several values at once. Their real strength comes from entanglement: when two qubits are entangled, the state of one determines the state of the other, even if they are not physically connected. Multiplied across many qubits, these correlations are what allow a quantum machine to explore many possibilities together. Entanglement also lets quantum processors share information without sharing the qubits themselves, which is the basis of distributed quantum computing.

The Oxford method works in two steps. Light links the strontium atoms across the two sites. Local operations then extend the entanglement to the calcium atoms, so that the four atoms form one shared state. The calcium is there for its stability: it is less sensitive to magnetic noise than strontium, and it preserves the quantum state for much longer. Using two atom types also beat the single-type approach, which kept entanglement at a few milliseconds. “Different types of atoms offer different advantages and disadvantages for quantum applications,” said Dougal Main, a researcher at Oxford. “Having more than one type in your quantum computer lets you take the best from each.”

What changes for the field is the ability to keep distant atoms coordinated for longer. Gabriel Araneda, also at Oxford, pointed to uses that depend on this: “That could include quantum computing, more sensitive measurements made across remote locations, and comparisons between different types of atomic clocks.” The gain is for researchers and for future quantum networks first; the sources give no timeline, no figures on how often the link fails, and no plan for scaling beyond four atoms. A 10-second link is a strong laboratory result, not yet a service anyone can buy.