Often in physics, we can separate the object from the environment and the experimental apparatus from what’s being measured, but that separation is approximate. In quantum systems, those distinctions break down, to the point where the environment “measures” the system, in ways we don’t fully understand even after nearly a century of study. (A lot of nonsense has been written about the subject, too, which is a rant for another day.) A new experiment may help mitigate some of the problems of system-environment interaction, through understanding how photons and atoms couple—and when they do not.

One remaining frontier is comprehension of how systems gradually lose coherence via interactions with their environment, which prevents their usefulness in quantum computing. A new set of experiments by Yinnon Glickman, Shlomi Kotler, Nitzan Akerman, and Roee Ozeri revealed part of the mechanism by which environment disrupts quantum systems: photons. They found that photons that interacted with a quantum system can end up correlated with the system’s state, the hallmark of entanglement. By careful preparation of the atom’s state, it may be possible to reduce the loss of quantum information to the environment, and thus extend the life of these systems. [Read more…]