Environmental noise paradoxically preserves the coherence of a quantum system

Environmental noise paradoxically preserves the coherence of a quantum system

6 years ago
Anonymous $CLwNLde341

https://phys.org/news/2018-05-environmental-noise-paradoxically-coherence-quantum.html

The group, led by Seigo Tarucha of the RIKEN Center for Emergent Matter Science, set up a system of three quantum dots in which electron spins could be individually controlled with an electric field. They began with two entangled electron spins in one of the end quantum dots, while keeping the center dot empty, and transferred one of these spins to the center dot. They then swapped the center dot spin with a third spin in the other end dot using electric pulses, so that the third spin was now entangled with the first. The entanglement was stronger than expected, and based on simulations, the researchers realized that the environmental noise around the system was, paradoxically, helping the entanglement to form.

According to Takashi Nakajima, the first author of the study, "We discovered that this derives from a phenomenon known as the 'quantum Zeno paradox,' or 'Turing paradox,' which means that we can slow down a quantum system by the mere act of observing it frequently. This is interesting, as it leads to environmental noise, which normally makes a system incoherent, Here, it made the system more coherent."