Quantum Control with Spinor Bose-Einstein Condensates

Publication Date


Document Type



Physics and Astronomy


Atomic, Molecular and Optical Physics

Publication Title

51st Annual Meeting of the American Physical Society Division of Atomic, Molecular and Optical Physics

Conference Location

Portland, OR


Understanding and controlling many-body quantum systems in noisy environments is paramount to developing robust quantum technologies. An external environment can be thought of as a "measurement reservoir"' which extracts information about the quantum system. Cold atoms are well suited to examine system-environment interaction via weak (i.e. minimally destructive) measurement techniques, wherein the measurement probe acts as the environment and provides a record of system dynamics. The measurement record can then be used in a feedback scheme, leading to real time control of quantum gases. I will discuss our proposal to use weak measurement and feedback to engineer new phases in spin-1/2 Bose-Einstein condensates. We show that measurement and feedback alters the effective Hamiltonian of the system, thereby driving phase transitions reminiscent of a quantum quench for the closed system. We also develop a feedback cooling protocol which prevents runaway heating of the condensate due to measurement backaction. Our results provide a new route toward Hamiltonian engineering in many-body systems.