https://phys.org/news/2018-11-coping-errors-quantum-age.html

Just like their classical counterparts, quantum computers are built from imperfect components, and they are far more sensitive to disturbances from the outside. This leads inescapably to errors as calculations are executed. For conventional computers, there exists a well-established toolkit for detecting and correcting such errors. Quantum computers will rely even more on locating and fixing errors. This requires conceptually different approaches that take into account the fact that information is encoded in quantum states. In particular, reading out quantum information repeatedly without disturbing it, a requirement for detecting errors, and reacting in real time to reverse these errors pose considerable challenges.

The Home group encodes quantum information in the quantum states of single ions that are strung together in a trap. Typically, these strings contain ions of only one species. But Ph.D. students Vlad Negnevitsky and Matteo Marinelli, together with postdoc Karan Mehta and further colleagues, have now created strings in which they trapped two different species—two beryllium ions (9Be+) and one calcium ion (40Ca+). Such mixed-species strings have been produced before, but the team has used them in novel ways.