Invited Article: A precise instrument to determine the Planck constant, and the future kilogram
Abstract
A precise instrument, called a watt balance, compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. We describe in this paper the fourthgeneration watt balance at the National Institute of Standards and Technology (NIST), and report our initial determination of the Planck constant obtained from data taken in late 2015 and the beginning of 2016. A comprehensive analysis of the data and the associated uncertainties led to the SI value of the Planck constant, h = 6.626 069 83(22) × 10{sup −34} J s. The relative standard uncertainty associated with this result is 34 × 10{sup −9}.
 Authors:
 National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899 (United States)
 (United States)
 Publication Date:
 OSTI Identifier:
 22597953
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 29 ENERGY PLANNING, POLICY AND ECONOMY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BALANCES; COMPARATIVE EVALUATIONS; ECONOMICS; HALL EFFECT; METERS; PLANCK LAW
Citation Formats
Haddad, D., Email: darine.haddad@nist.gov, Seifert, F., Williams, C., University of Maryland, Joint Quantum Institute, College Park, Maryland 20742, Chao, L. S., Li, S., Newell, D. B., Pratt, J. R., and Schlamminger, S., Email: stephan.schlamminger@nist.gov. Invited Article: A precise instrument to determine the Planck constant, and the future kilogram. United States: N. p., 2016.
Web. doi:10.1063/1.4953825.
Haddad, D., Email: darine.haddad@nist.gov, Seifert, F., Williams, C., University of Maryland, Joint Quantum Institute, College Park, Maryland 20742, Chao, L. S., Li, S., Newell, D. B., Pratt, J. R., & Schlamminger, S., Email: stephan.schlamminger@nist.gov. Invited Article: A precise instrument to determine the Planck constant, and the future kilogram. United States. doi:10.1063/1.4953825.
Haddad, D., Email: darine.haddad@nist.gov, Seifert, F., Williams, C., University of Maryland, Joint Quantum Institute, College Park, Maryland 20742, Chao, L. S., Li, S., Newell, D. B., Pratt, J. R., and Schlamminger, S., Email: stephan.schlamminger@nist.gov. 2016.
"Invited Article: A precise instrument to determine the Planck constant, and the future kilogram". United States.
doi:10.1063/1.4953825.
@article{osti_22597953,
title = {Invited Article: A precise instrument to determine the Planck constant, and the future kilogram},
author = {Haddad, D., Email: darine.haddad@nist.gov and Seifert, F. and Williams, C. and University of Maryland, Joint Quantum Institute, College Park, Maryland 20742 and Chao, L. S. and Li, S. and Newell, D. B. and Pratt, J. R. and Schlamminger, S., Email: stephan.schlamminger@nist.gov},
abstractNote = {A precise instrument, called a watt balance, compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. We describe in this paper the fourthgeneration watt balance at the National Institute of Standards and Technology (NIST), and report our initial determination of the Planck constant obtained from data taken in late 2015 and the beginning of 2016. A comprehensive analysis of the data and the associated uncertainties led to the SI value of the Planck constant, h = 6.626 069 83(22) × 10{sup −34} J s. The relative standard uncertainty associated with this result is 34 × 10{sup −9}.},
doi = {10.1063/1.4953825},
journal = {Review of Scientific Instruments},
number = 6,
volume = 87,
place = {United States},
year = 2016,
month = 6
}

The best measurement of the Planck constant is now derived from the watt balance method. This method measures mechanical power, in reference units of the kilogram (artifact mass standard), second (atomic clocks), and meter (lasers), in ratio to electrical power, in reference units of the volt (Josephson effect) and ohm (quantum Hall effect). Of these reference standards, only the kilogram is still an artifact standard. Thus a high precision measurement of the Planck constant is equivalent to monitoring the SI kilogram artifact, and may be used to redefine the kilogram. This talk will summarize the complexity of making a Planckmore »

The precise timedependent solution of the Fokker–Planck equation with anomalous diffusion
We study the time behavior of the Fokker–Planck equation in Zwanzig’s rule (the backwardIto’s rule) based on the Langevin equation of Brownian motion with an anomalous diffusion in a complex medium. The diffusion coefficient is a function in momentum space and follows a generalized fluctuation–dissipation relation. We obtain the precise timedependent analytical solution of the Fokker–Planck equation and at long time the solution approaches to a stationary powerlaw distribution in nonextensive statistics. As a test, numerically we have demonstrated the accuracy and validity of the timedependent solution.  Highlights: • The precise timedependent solution of the Fokker–Planck equation with anomalousmore » 
Retaining large and adjustable elastic strains of kilogramscale Nb nanowires [Better Superconductor by Elastic Strain Engineering: Kilogramscale FreeStanding Niobium Metal Composite with Large Retained Elastic Strains]
Crystals held at ultrahigh elastic strains and stresses may exhibit exceptional physical and chemical properties. Individual metallic nanowires can sustain ultralarge elastic strains of 47%. However, retaining elastic strains of such magnitude in kilogramscale nanowires is challenging. Here, we find that under active load, ~5.6% elastic strain can be achieved in Nb nanowires in a composite material. Moreover, large tensile (2.8%) and compressive (2.4%) elastic strains can be retained in kilogramscale Nb nanowires when the composite is unloaded to a freestanding condition. It is then demonstrated that the retained tensile elastic strains of Nb nanowires significantly increase their superconducting transitionmore »Cited by 4 
Planck 2015 results: VII. High Frequency Instrument data processing: Timeordered information and beams
The Planck High Frequency Instrument (HFI) has observed the full sky at six frequencies (100, 143, 217, 353, 545, and 857 GHz) in intensity and at four frequencies in linear polarization (100, 143, 217, and 353 GHz). In order to obtain sky maps, the timeordered information (TOI) containing the detector and pointing samples must be processed and the angular response must be assessed. The full mission TOI is included in the Planck 2015 release. This study describes the HFI TOI and beam processing for the 2015 release. HFI calibration and map making are described in a companion paper. The mainmore » 
Planck 2015 results: II. Low Frequency Instrument data processings
In this paper, we present an updated description of the Planck Low Frequency Instrument (LFI) data processing pipeline, associated with the 2015 data release. We point out the places where our results and methods have remained unchanged since the 2013 paper and we highlight the changes made for the 2015 release, describing the products (especially timelines) and the ways in which they were obtained. We demonstrate that the pipeline is selfconsistent (principally based on simulations) and report all null tests. For the first time, we present LFI maps in Stokes Q and U polarization. Finally, we refer to other relatedmore »