The most significant change in the possible future revision of the SI would be in the kilogram, the only one of the SI's seven base units* still defined in terms of a material "artifact": a 130 ...

A key meeting this month is likely to see all SI units defined for the first time in terms of fundamental constants. Benjamin Skuse explains the change. Skip to main ... New: The kelvin (K) is defined ...

In May, a team of German physicists at the Physikalisch-Technische Bundesanstalt made the most precise measurements yet of the Boltzmann constant, which will be used to define units of temperature.

Sufficient progress towards redefining the International System of Units (SI) in terms of exact values of fundamental constants has been achieved. Exact values of the Planck constant h, elementary ...

Recognizing the importance of linking SI units to such invariant quantities, ... to the 2014 CODATA adjusted value of the Boltzmann constant, along with the 2010 3 and 2014 18 CODATA values ...

Scientists from the Physikalisch-Technische Bundesanstalt (PTB) have determined the Boltzmann constant by means of a dielectric-constant gas thermometer with such accuracy that all obstacles to ...

A Boltzmann constant determination based on Johnson noise thermometry. Metrologia , 2017; DOI: 10.1088/1681-7575/aa7b3f Jifeng Qu, Samuel Benz, Kevin Coakley, Horst Rogalla, Weston Tew, D White ...

This SI unit, used by chemists to define an amount of atoms or molecules, has been defined since 1971 in relation to the kilogram, as “the amount of substance of a system which contains as many ...

Instead, the new SI would be based on constants of nature such as the Boltzmann constant, which depends fundamentally on quantum mechanics, the theory that describes matter and energy at the ...

The kilogram is shrinking. The official object that defines the mass of a kilogram is a tiny, 139-year-old cylinder of platinum and iridium that resides in a triple-locked vault near Paris.

Although this is less accurate than other techniques, the researchers think that they should be able to reduce the uncertainty to 6 ×10 –6 in the future, which would make it an attractive method for ...