A crystal stores quantum messages in 11 channels for on-demand retrieval

An integrated device stored time-based and five-path quantum states with fidelities above 99% and 96%, respectively.

Editorial illustration — not from the study.

The device uses waveguides—structures that guide light—written into a europium-doped yttrium silicate crystal. Electrodes on the chip independently control when each of its 11 channels releases a stored quantum state, enabling random access to the memory rather than requiring all channels to be read in a fixed sequence.

In tests, the memory stored three time-bin qubits, which encode information in different arrival times, with fidelity exceeding 99%. It also stored quantum states using five possible light paths with fidelity above 96%.

What the crystal stored

The researchers demonstrated an 11-channel integrated quantum memory based on laser-written waveguides in a 151Eu3+:Y2SiO5 crystal. On-chip electrode arrays independently controlled the read-out time in each channel through an electrically induced change in the crystal’s atomic response. The memory achieved random-access storage of three time-bin qubits with fidelity above 99% and stored five-dimensional path-encoded quantum states with fidelity above 96%.

Why multiple channels matter

Quantum memories temporarily store quantum states so they can be used later in communication or computation. A memory that can independently access multiple channels could support more flexible quantum networks and photonic quantum-computing systems than a single-channel device. The integrated crystal-based design also provides a hardware platform for combining random access with high-dimensional quantum states on a chip.

Evidence and open limits

This is an experimental demonstration of a device, with performance assessed through the reported storage fidelities for time-bin and path-encoded states. The abstract does not provide details about storage duration, efficiency, loss, operating conditions, or how the device compares with other memories. It also does not establish how the system would perform when scaled beyond 11 channels or deployed in a complete quantum network.

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