The Bhattacharya group is broadly interested in light-matter interactions from the perspective of fundamental science as well as technological applications. Currently, it is focused on the interplay of electromagnetic modes of radiation, such as laser light, with mechanical oscillators and cold atoms. Major aims are the cooling of macroscopic objects into the quantum regime and establishing the limits to quantum sensing of mechanical displacement and force, for example. These investigations are expected to test the foundation of quantum mechanics as well as to yield next-generation sensors that circumvent the limits posed by quantum mechanics to their sensitivity. The work is theoretical, involving analytical as well as numerical calculations, using the techniques of quantum optics, atomic physics and condensed matter physics. Close collaborations exist with experimental groups locally, nationally, as well as internationally. The program involves researchers at every level, including undergraduate, master's, and doctoral students as well as postdoctoral scholars. Recent funding sources include the Air Force Office of Scientific Research, the Office of Naval Research, and the National Science Foundation.