Protecting qubits from errors using photons in a silicon chip

The photonic chip is key to nurturing quantum computers.


Quantum computers can process information millions of times faster than classic computers. They offer more computing power for specific, very tricky problems.

Qubits or quantum bits are the fundamental building block for quantum information processes. Due to fragile quantum states, the qubits pick up errors very quickly. Sometimes, they get damaged by the environment of the everyday world.

Quantum error-correcting codes are a method to protect or nurture qubits by embedding them in a more robust entangled state of many particles. Scientists at Bristol’s Quantum Engineering and Technology Laboratories (QETLabs) have demonstrated this using a quantum photonic chip.

photonic chip
The photonic chip generates and entangles ensembles of photons. It can implement a range of quantum error-correcting codes.

Scientists showed how large states of entangled photons could contain individual logical qubits and protect them from the harmful effects of the classical world.

Dr. Caterina Vigliar, the first author of the work, said: “The chip is versatile. It can be programmed to deliver different kinds of entangled states called graphs. Each graph protects logical quantum bits of information from different environmental effects.”

Anthony Laing, co-Director of QETLabs, and an author of the work said: “Finding ways to deliver large numbers of error-protected qubits efficiently is key to one-day delivering quantum computers.”

Journal Reference:
  1. Caterina Vigliar, Stefano Paesani et al. Error-protected qubits in a silicon photonic chip. Nat. Phys. (2021). DOI: 10.1038/s41567-021-01333-w