Quantum Technology

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Director: Dr. Jinhee Kim (jinhee@kriss.re.kr)

Team for

  • Quantum Candela
  • Quantum Information
  • Emerging Quantum Metrology
  • Quantum Theory
  • Spin Convergence Research
  • Scanning Probe Microscopy
  • Watt Balance
  • Quantum Metrology Triangle
  • Optical Lattice Clock

Its current R&D project include the following subjects :

  • Quantum-based nanotechnologies for use in precision measurements
  • Development of quantitative analysis method for intracellular nanoparticle tracking

R&D Highlights _ Quantum Technology

Watt balance compares mechanical power to electrical power. Electrical power is traceable to the Josephson and quantum Hall effects. Due to the two macroscopic quantum phenomena, electrical power is proportional to the Planck constant and the frequency of the microwave irradiated onto the Josephson junctions. SI units will be redefined by fixing numerical values of the seven constants, including the Planck constant, elementary charge, and the Avogadro constant. In the new SI, watt balance can realize the kilogram traceable to the speed of light, hyperfine splitting frequency of Cs atoms, and the Planck constant.
KRISS started the construction of the watt balance in 2012 in preparation of the forthcoming kilogram redefinition. The KRISS watt balance includes a linear motor for vertical movement, pure linear motion guides (a piston guide and a 1 D.O.F flexure guide) and a commercial weighing cell, a magnet and a coil position measurement system. The velocity of the moving coil was controlled within 4.0×10-3 (1σ) at the velocity of 2 mm s-1. Using a 3-vertical homodyne laser interferometer, the velocity ripple of the coil located inside the magnet was measured within the level of 7.3×10-3 (1σ) at the same speed. A magnet assembly, which consists of two permanent magnet rings and closed yokes, was fabricated. A flux shunt was designed for the magnet to minimize the temperature effect. The yokes were divided into three parts: top, center, and bottom yokes. The center yoke was chamfered and reassembled to improve the uniformity. The uniformity of the magnetic field was within 3.9×10-4 over a vertical distance of 20 mm. We are aiming to measure the Planck constant with an uncertainty of 5×10-8 by 2018.