Researchers Create Entangled, Squeezed Light At Room Temperature

If two objects are entangled, they must be seen as a unified whole regardless of how far from each other they are. They will still behave as one unit—and if the objects are measured individually, the results will be correlated to such a degree that it cannot be described based on the classical laws of nature. This is only possible using quantum mechanics.

Entanglement is not restricted to pairs of objects. In their efforts to observe quantum phenomena on a macroscopic scale, the researchers at bigQ managed to create a network of 30,000 entangled pulses of light arranged in a two-dimensional lattice distributed in space and time. It is almost like when a myriad of colored threads are woven together into a patterned blanket.

The researchers have produced light beams with special quantum mechanical properties (squeezed states) and woven them together using optical fibre components to form an extremely entangled quantum state with a two-dimensional lattice structure—also called a cluster state.

“As opposed to traditional cluster states, we make use of the temporal degree of freedom to obtain the two-dimensional entangled lattice of 30.000 light pulses. The experimental setup is actually surprisingly simple. Most of the effort was in developing the idea of the cluster state generation,” says Mikkel Vilsbøll Larsen, the lead author of the work.

Creating such an extensive degree of quantum physical entanglement is—in itself—interesting basic research. The cluster state is also a potential resource for creating an optical quantum computer. This approach is an interesting alternative to the more widespread superconducting technologies, as everything takes place at room temperature.