An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
The NIST ac-dc Difference Project provides U.S. industry with the essential link between ac and the corresponding dc electrical standards via a world-class
Theory is being developed and used to devise methods for preserving and exploiting the quantum behavior of ever-larger systems for metrology, communication, and
NIST provides calibration services for force-measuring instruments by applying known forces, compression, tension or both, to the elastic transducer and
NIST maintains the national standard for mass in the form of the prototype kilograms (K4, K20, K79, K92, and K102) and provides services to support the parts of
Every four years, the Committee on Data for Science and Technology (CODATA) issues recommended values of the fundamental physical constants. The values are
The Dynamic Mechanical Metrology Project develops new methods to provide accuracy in, and provides calibration services for, acoustic, vibration, acceleration
Our country's way of life depends on the electric power distribution system. Keeping the national electric grid in good working order -- and ensuring power is
This project provides the basis for a new definition of mass, based on unchanging quantum properties of nature rather than a physical artifact. This is
This project aims to provide the world's best basis for accurate impedance measurements by tying the U.S. legal system of electrical units to the International
Accurate measurements of atomic wavelengths, energy levels, oscillator strengths and isotope and hyperfine structure using diffraction grating spectrographs
The International System of Units (SI) provides definitions of units of measurement that are widely accepted in science and technology and which set measurement
The quantum optics of light interacting with semiconductor-based nanostructures is being studied to extend concepts of entanglement and coherence in atomic
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
Laser cooling of atoms is a powerful and widely used tool in atomic physics. Traditional laser cooling relies primarily on the mechanical effect of single
The Newtonian constant of gravitation G is one of the most fundamental constants of classical physics. Recent measurements of G are in disagreement, with
Nonlinear optics provides a way to generate light with different frequencies and different quantum statistical properties. We have developed a nonlinear 4-wave
Since 1970, the National Institute of Standards and Technology (NIST) has awarded Precision Measurement Grants for significant research in the field of
Since the inception of the SI system of units, physical mass artifacts have been disseminated in order to realize the unit of the kilogram, essential to a broad