A novel approach to testing for the presence of the virus that causes Covid-19 may lead to tests that are faster, less expensive, and potentially less prone to erroneous results than existing detection methods. Though the work, based on quantum effects, is still theoretical, these detectors could potentially be adapted to detect virtually any virus, the researchers say. The new approach is described in a paper published Thursday in the journal Nano Letters, by Changhao Li, an MIT doctoral student; Paola Cappellaro, a professor of nuclear science and engineering and…