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Quantum Measurement Division

The Quantum Measurement Division (QMD) provides the physical foundation for the International System of Units (Système International d'Unités or SI), colloquially referred to as the metric system.

We achieve this through precision measurements of various fundamental constants, realization of resistance and voltage through the quantum hall effect and Josephson effect respectively, and through our determination of the best values of the fundamental constants done under the auspices of the Task Group on Fundamental Constants of the Committee on Data for Science and Technology (CODATA, an interdisciplinary unit of the Scientific Committee of the International Council for Science).

The division is currently heavily engaged in the redefinition of the SI that is expected to occur in 2018. We support this effort through R&D and through interactions with the International Bureau of Weights and Measures (BIPM) and its consultative committees including the Consultative Committee for Units (CCU), the Consultative Committee for Electricity and Magnetism (CCEM), and the Consultative Committee for Mass and Related Quantities (CCM).

As part of this effort, NIST is building a new Watt Balance which - prior to the redefinition -will be used to make one final precision measurement of the Planck constant. After the redefinition, it will become the means for the realization of the kilogram in the United States.

The planned redefinition of the SI in 2018 will achieve the goal of turning the SI into a system based on fundamental constants and properties of nature. In fact, the new redefined SI will be largely based on quantum mechanics and its generalizations. including quantum electrodynamics.

As such, the strategy of the QMD is to:

  • investigate and exploit quantum behavior to create measurement tools and capabilities at and beyond the standard quantum limit
  • explore the basic capabilities of complex quantum systems to better understand what future quantum technologies will allow us to measure, compute, and simulate
  • exploit this knowledge to create the foundation to realize and disseminate mass, force, and electrical quantities and improve our ability to realize these quantities
  • disseminate these quantities from first principles, through specially developed instruments and methodologies, or through scaling that minimizes the loss of accuracy of the various technologies involved relative to the best available quantum or classical technology
  • to create critically evaluated data relevant to both fundamental constants and atomic properties

Redefining the Kilogram

K20 prototype mass

For more than a century, the kilogram (kg) – the fundamental unit of mass in the International System of Units (SI) – has been defined as exactly equal to the mass of a small polished cylinder, cast in 1879 of platinum and iridium, which is kept in a triple-locked vault on the outskirts of Paris.

That object is called the International Prototype of the Kilogram (IPK), and the accuracy of every measurement of mass or weight worldwide, whether in pounds and ounces or milligrams and metric tons, depends on how closely the reference masses used in those measurements can be linked to the mass of the IPK.

That situation is about to change. The world metrology community plans to redefine the kilogram soon, freeing it from its embodiment in one golf-ball-sized artifact at one location, and basing it instead on a constant of nature. That transformation will be as profound as any in the history of measurement.  MORE

News and Updates

Industry Impacts

Massive Forces for Heavy Industry

Measuring large forces, such as the thrust of a rocket engine or the deflection of an aircraft wing, requires well-calibrated force sensors. NIST’s unique

Projects and Programs

SI-traceable Dynamic Force

Traditional calibration methods for force transducers are static, with a known constant force applied to the transducer and compared to the transducer

Metrology of the Ohm

Resistance standards traceable to NIST provide references for measurements of current at levels from 3000 A to below 20 fA and are used to support a wide

Memory

Critical to quantum information applications is the need to store a quantum state while other qbits are created or processed.

Software

Awards

Alan Migdall Elected OSA Fellow

Optical Society of America (OSA) members who have served with distinction in the advancement of optics may be proposed for election to the...

2019 PECASE - Alexey Gorshkov

The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to...

Press Coverage

A more perfect unit: the new mole

Popular Science
A video about the redefinition of the mole, featuring NIST's Savelas Rabb, Robert Vocke, and Stephan Schlamminger.

Contacts

Division Chief