Report of the Topical Group on Quantum Sensors for Snowmass 2021

Quantum Sensors offer great potential for providing enhanced sensitivity in high energy physics experiments. In this report we provide a summary of key quantum sensors technologies - interferometers, optomechanics, and clocks; spin dependent sensors; superconducting sensors; and quantum calorimeters - highlighting existing experiments along with areas for development. We also provide a set of key messages intended to further advance the state of quantum sensors used for high energy physics specific applications.