More robust quantum systems using hidden symmetry

Researchers at University of Cambridge have found a way to protect highly fragile quantum systems from noise, which could aid in the design and development of new quantum devices.

They have shown that microscopic particles can remain intrinsically linked, or entangled, over long distances even if there are random disruptions between them. Using the mathematics of quantum theory, they discovered a simple setup where entangled particles can be prepared and stabilized even in the presence of noise by taking advantage of a previously unknown symmetry in quantum systems.

They modeled an atomic system in a lattice formation, where atoms strongly interact with each other, hopping from one site of the lattice to another. The authors found if noise were added in the middle of the lattice, it didn’t affect entangled particles between left and right sides. This surprising feature results from a special type of symmetry that conserves the number of such entangled pairs.

They showed this hidden symmetry protects the entangled pairs and allows their number to be controlled from zero to a large maximum value. (

The paper has been published in Physical Review Letters.

Read more.