Fundamentals and device techniques for quantum measurements will be developed in this subgroup. The developed results will be transferred to accelerate R&D of other subgroups in this project. One of main aims is to establish new quantum measurement techniques and to apply the developed techniques to a variety of fields of fine measurements. We are covering wide spectral fields: Photon detector/mid-infrared light source (M. Yamanishi), Quantum measurement devices based on semiconductor nano-structures (T. Fujisawa and T. Ohta), High sensitivity measurement technique by photon superposition states (S. Takeuchi), Magnetic flux meter by atom BEC (T. Hirano), and Superconductor chip for quantum measurements based on atom interferometer (T. Mukai). The developed devices/techniques will be combined resultantly to realize synergetic quantum systems.