Nathan D. Gemelke, PhD
Assistant Professor, Department of Physics
Pennsylvania State University
Quantum Measurement and Back-action Manipulation of Many Ultra-cold Atoms
Abstract: For over a century, quantum mechanics has enabled a rapid and thorough understanding of a vast number of physical systems. However it continues to demand subtle redefinition of simple notions in how we understand the material world, particularly when systems exhibit a high degree of ‘entanglement’ - a peculiar type interdependence of state - between the many microscopic parts of a macroscopic body. A number of simple questions remain surprisingly incompletely answered. What simple macroscopic behaviors can arise from a complex and entangled quantum system, and what cannot? Can we in some way describe the fundamental particles and interactions of nature as derivative of simpler set of underlying quantum physics? How do strongly entangled many-body systems behave far from thermal equilibrium, and how can we harness this information to drive new technologies? For example, how can information be practically stored and processed in inherently quantum mechanical ways? We believe a single laboratory development can address many of these questions in a generalized way, providing not only non-classical means for simulation of well-known many-body quantum systems, but the ability to proactively engineer new quantum phases of matter specifically chosen to shed light on these foundational questions in physics. If a complex system of interacting quantum bodies, in this case a dilute gas of laser- and evaporatively-cooled neutral atoms, can be assembled from the bottomup, with complete control of its initial state and highly tunable microscopic interactions - and if it can be probed repeatedly and non-destructively at sufficient spatial resolution by an array of secondary atoms, progress can be made on all these related fronts. This novel apparatus, which we refer to as a collisional microscope, combines the well-developed and versatile technology of high-resolution optical manipulation and detection of laser-cooled neutral atoms with new quantum measurement techniques, using highly controlled collisions of cold atoms to probe the many-body quantum phases they form.