Abstract: Fundamental physical laws dictate the performance bounds of all technologies. Over the last century, advances in nanotechnology and integrated circuits have driven the performance of computing, communications, and sensing toward these bounds. As scaling continues, classical limits are increasingly constraining further improvements. The advent of quantum technologies opens paths to overcoming some of these limits and to building technologies that operate at the fundamental physical limits. In this talk, I give an overview of the fundamental physical limits in computing, communications, and sensing. Across these three domains, I present integrated systems we realized in silicon photonics and electronics that serve as a proof-of-concept for deployable technologies operating at these limits. The demonstrations include (i) photonic quantum computers, (ii) quantum-limited coherent transceivers, and (iii) quantum phased arrays. For each system, I address the theory, design, experiment, and application, and outline a vision for how these technologies can be practically deployed in the future.