B.N. Taylor’s research while affiliated with National Institute of Standards and Technology and other places

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Publications (13)


Values of the Planck constant h inferred from the input data in table 1 and the CODATA 2017 value in chronological order from top to bottom. The inner green band is  ±20 parts in 10⁹ and the outer grey band is  ±50 parts in 10⁹. KB: Kibble balance; XRCD: x-ray-crystal-density.
Table 2 . The CODATA 2017 adjusted values of h, e, k, and N A . 
Values of the Boltzmann constant k inferred from the key input data in table 1 and the CODATA 2017 value in chronological order from top to bottom. The inner green band is  ±5 parts in 10⁷ and the outer grey band is  ±15 parts in 10⁷. AGT: acoustic gas thermometry; DCGT: dielectric constant gas thermometry; JNT: Johnson noise thermometry.
The CODATA 2017 Values of \bm{h}, \bm{e}, \bm{k}, and \bm{NAN_{\rm A}} for the Revision of the SI
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  • Full-text available

January 2018

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306 Reads

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235 Citations

D B Newell

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F Cabiati

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J Fischer

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[...]

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Z Zhang

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 charge e, Boltzmann constant k, and Avogadro constant N A from the CODATA 2017 Special Adjustment of the Fundamental Constants are presented here. These values are recommended to the 26th General Conference on Weights and Measures to form the foundation of the revised SI.

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The New International System of Units: The Role of the Committee on Data for Science and Technology (CODATA)

December 2011

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16 Reads

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2 Citations

NCSLI Measure

The mission of the Committee on Data for Science and Technology (CODATA) of the International Council for Science is to strengthen international science for the benefit of society by promoting improved scientific and technical data management and use. One of their most visible outputs comes from the Task Group on Fundamental Constants (TGFC), which periodically performs a comprehensive least-squares adjustment of the values of the constants and produces the well-known and widely cited publication entitled “CODATA recommended values of the fundamental physical constants: year” (freely available at http://physics.nist.gov/cuu/constants). When the proposal to change the International System of Units (SI) by redefining the kilogram, ampere, kelvin, and mole in terms of fixed values of the Planck constant h, elementary charge e, Boltzmann constant k, and Avogadro constant NA, respectively, is implemented in the near future, it will be the responsibility of the TGFC to provide these values. In this presentation, the least-squares adjustment procedure will be outlined and illustrated with reference to current state-of-the-art measurements in several physical disciplines.


The 2006 adjustment of the fundamental constants: Looking towards 2010

July 2008

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22 Reads

CPEM Digest (Conference on Precision Electromagnetic Measurements)

A new set of values of the basic fundamental constants has been recommended by the Committee on Data for Science and Technology (CODATA) (http://phvsics.nist.gov/cuu/Constants/). It is based on a least-squares adjustment that incorporates new data that became available before the closing date of 31 December 2006 (known as the 2006 LSA). A number of key advances in experiment and theory have led to significant improvements in our knowledge of the values of the constants. The consequences of the new results and how the values were determined will be discussed.


CODATA recommended values of the fundamental physical constants: 1998

June 2008

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216 Reads

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2,206 Citations

Journal of Physical and Chemical Reference Data

This paper gives the 2006 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2006 adjustment takes into account the data considered in the 2002 adjustment as well as the data that became available between 31 December 2002, the closing date of that adjustment, and 31 December 2006, the closing date of the new adjustment. The new data have led to a significant reduction in the uncertainties of many recommended values. The 2006 set replaces the previously recommended 2002 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.


Precise calculation of transition frequencies of hydrogen and deuterium based on a least-squares analysis

April 2006

We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g-factor of the electron, which was previously the most accurate prediction of QED.



Redefinition of the kilogram: A decision whose time has come

April 2005

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152 Reads

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58 Citations

Metrologia

The kilogram, the base unit of mass in the International System of Units (SI), is defined as the mass m (K) of the international prototype of the kilogram. Clearly, this definition has the effect of fixing the value of m (K) to be one kilogram exactly. In this paper, we review the benefits that accrue would if the kilogram were redefined so as to fix the value of either the Planck constant h or the Avogadro constant N-A Instead of m (K), without waiting for the experiments to determine h or N-A currently underway to reach their desired relative standard uncertainty of about 10(-8). A significant reduction in the uncertainties of the SI values of many other fundamental constants would result from either of these new definitions, at the expense of making the mass m (K) of the international prototype a quantity whose value would have to be determined by experiment. However, by assigning a conventional value to m (K), the present highly precise worldwide uniformity of mass standards could still be retained. The advantages of redefining the kilogram immediately outweigh any apparent disadvantages, and we review the alternative forms that a new definition might take.


On the redefinition of the kilogram

March 2003

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68 Reads

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49 Citations

A new definition of the kilogram based on the relations E = mc2 and E = hν is proposed, motivated by recent progress in the development of moving-coil watt balances. Such a balance together with the definition promises to provide a practical means of directly calibrating standards of mass.


Definitions of the units radian, neper, bel and decibel

March 2003

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638 Reads

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25 Citations

The definition of coherent derived units in the International System of Units (SI) is reviewed, and the important role of the equations defining physical quantities is emphasized in obtaining coherent derived units. In the case of the dimensionless quantity plane angle, the choice between alternative definitions is considered, leading to a corresponding choice between alternative definitions of the coherent derived unit - the radian, degree or revolution. In this case the General Conference on Weights and Measures (CGPM) has chosen to adopt the definition that leads to the radian as the coherent derived unit in the SI. In the case of the quantity logarithmic decay (or gain), also sometimes called decrement, and sometimes called level, a similar choice of defining equation exists, leading to a corresponding choice for the coherent derived unit - the neper or the bel. In this case the CGPM has not yet made a choice. We argue that for the quantity logarithmic decay the most logical choice of defining equation is linked to that of the radian, and is that which leads to the neper as the corresponding coherent derived unit. This should not prevent us from using the bel and decibel as units of logarithmic decay. However, it is an important part of the SI to establish in a formal sense the equations defining physical quantities, and the corresponding coherent derived units.


The role of fundamental constants in the International System of Units (SI): Present and future

May 2001

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24 Reads

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39 Citations

IEEE Transactions on Instrumentation and Measurement

This paper addresses the role of fundamental constants in (1) the current definitions of the SI base units; (2) practical representations of SI electric units and the consistency of those representations with the SI as deduced from the 1998 CODATA recommended values of the constants; and (3) redefinition of the kilogram and the impact on realizations of SI electric units of a newly proposed definition that fixes the value of the Planck constant h


Citations (10)


... The International Council of Science established CODATA for facilitating improved scientific and technical data management and use for addressing issues of scientific interest for the benefit of society. Since then it seeks to provide the best values of fundamental constants and conversion factors used in physics and chemistry to scientific and metrology communities [24] Recommended laboratories to pursue their work with a view to monitoring the stability of IPK and in due course opening the way for the new definition of the unit of mass-based upon fundamental atomic constant Considered watt balance and X-ray Crystal Density (XRCD) (that counts the number of atoms in a silicon sphere) methods as candidates that could link mass with fundamental constant: watt Balance through Planck constant and XRCD through Avogadro constant. NIST USA, NPL UK, and NRLM Japan were working towards development of watt balance and PTB Germany was working to refine the Si sphere method [28] 1999 21st CGPM Recommended in its resolution to redefine kg ...

Reference:

Journey of Kilogram from Physical Constant to Universal Physical Constant (h) via Artefact: A Brief Review
The New International System of Units: The Role of the Committee on Data for Science and Technology (CODATA)
  • Citing Article
  • December 2011

NCSLI Measure

... Since 1885, the fixed number of entities in one mole has been measured (with uncertainty) through various experiments, materials, and methods in which the mole is quantified by mass, Becker (2001), Mohr et al (2018), Newell et al (2018). The mass of one atom of carbon-12 is fixed. ...

The CODATA 2017 Values of \bm{h}, \bm{e}, \bm{k}, and \bm{NAN_{\rm A}} for the Revision of the SI

... The advantage of this choice is that the reference-state wave functions and the Dirac-Coulomb Green's function are known analytically. The computation of the point-nucleus bound wave functions in coordinate and momentum space is described in Ref. [45]. The radial Dirac-Coulomb Green's function is represented analytically in terms of regular and irregular Whittaker functions [45]. ...

CODATA Recommended values of the fundamental physical constants: 1998
  • Citing Article
  • April 2000

Review of Modern Physics

... The results display a relative drift of about 3 × 10 –8 over the course of a century[3,4], which is one of the facts that makes the current definition of the kilogram unsatisfactory. In an era of ever-increasing measurement precision this situation is no longer acceptable, so there is a strong desire among the national metrology institutes (NMIs)to move to a new, more robust definition of the unit of mass, as well as for the other base units of SI[5][6][7][8]. For the past few decades, significant efforts have been made to link the unit of mass to a fundamental constant of physics with high accuracy. For this purpose, some NMIs have essentially developed two experiments: one is the x-ray-crystal-density (XRCD) method based on single-crystal isotopically pure silicon-28 spheres[9,10], the other one involves either Kibble watt balances[11– 17]or a joule balance[18]—to link the unit of mass respectively to the Avogadro and Planck constants. ...

Redefinition of the kilogram: A decision whose time has come
  • Citing Article
  • April 2005

Metrologia

... The set of DCs consisting of h, e, k, and N A is the preferred variant. Other variants have also been proposed [8,9,19,20]. For example, in the opinion of the authors of [9], the attained level of the data of CODATA-2014 [13] determines a new context for selecting an optimal set of DCs by comparison with what had been selected in 2007 at the 23rd CGPM [6,23]. ...

On the redefinition of the kilogram
  • Citing Article
  • March 2003

... The QMU system's units are constructed from quantum measurements rather than arbitrary or macroscale standards. This approach aims to provide more precise and physically meaningful units for quantum processes and structures [46]. ...

The role of fundamental constants in the International System of Units (SI): Present and future
  • Citing Article
  • May 2001

IEEE Transactions on Instrumentation and Measurement