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The role of fundamental constants in the International System of Units (SI): Present and future
Abstract
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
... The first set of constants introduces two new references, i.e. the Planck and the Boltzmann constants h and k, thus allowing the kilogram and the kelvin to be redefined while maintaining the magnetic constant µ 0 as a reference for the electrical units. The second set allows for hypotheses of revision of the SI which have been in the air for a long time [1,[12][13][14][15], releasing µ 0 in favour of the electron charge e. The others maintain h, k and e as the most agreed, but take into account the requirement for referring also the time unit to fundamental constants, rather than to a particular parameter of a specific atom such as the Cs ground-state hyperfine transition frequency ν Cs . ...
... In matrix (15), the ith row/column pertains to the ith hierarchical level of the dissemination chain. Therefore, u s i embodies u s i−1 , so that u s i > u s i−1 . ...
... Therefore, u s i embodies u s i−1 , so that u s i > u s i−1 . Equation (15) shows that the common uncertainty u re associated with the realization of the unit introduces covariance terms in the covariance matrix. Moreover, it can be seen that, as mentioned, u re rapidly becomes negligible along the subsequent steps of the dissemination chain. ...
The trend towards an International System of Units (SI) based on fundamental constants has been confirmed and recent actions could result in the redefinition of the four units still necessary to cover all the quantities of interest for physics and chemistry. In this paper some issues whose solution is becoming critical with the approach of the General Conference on Weights and Measures (CGPM) of 2011 are discussed. The traditional kinds of definition and the new proposals are considered on the basis of their mathematical expressions and the advantageous features of the most advanced proposal are pointed out. The problem of choosing the set of fundamental constants to be adopted as reference quantities for the SI units is addressed and a general rule for verifying that the set is sufficient and non-redundant is pointed out in the form of a linear system giving also expressions of all the units as functions of the reference constants. A partial application to the most important units and different sets of constants offers some comparative criteria and shows the advantages of a set including both h and me. A general condition to be fulfilled by an experiment in order to realize an SI unit is given and a procedure suitable to optimize the availability of the best relization on a global basis is outlined. Finally, the dissemination process is analysed to show that the implied comparisons of standards at any level are not affected by the realization uncertainty, so that the process can be continued with the same standards, independently of any change in the basic reference quantities of the unit system.
... In recent years, there has been significant improvement in the stability and uncertainty of optical clocks, surpassing the performance of the current reference clock, i.e., the cesium microwave clock. Optical clocks demonstrate potential as the most promising candidate for the future redefinition of the second, based on optical transitions [1][2][3][4][5][6][7][8][9][10]. These clocks have found wide application in fundamental physics research. ...
... In Figure 3b, an exploded view of the probe beam optical setup is presented, illustrating the configuration of the springless mirror mounts. The 461nm probe laser is coupled into a non-adjustable collimator (1) to collimate the beam. The collimated beam has a diameter of approximately 1 mm and passes through a half-wave plate (3) and a wedge prism (5), finally entering the MOT vacuum chamber via a 45° mirror (9). ...
Compact and robust optical clocks are significant in scientific research and engineering. Here, we present a physical system for a strontium atomic optical clock with dimensions of 465 mm × 588 mm × 415 mm and a weight of 66.6 kg. To date, this is one of the most compact physical systems ever reported. The application of the magnetic shielding box in this physical system allowed the effect of external magnetic field fluctuation on cold atoms to be negligible. The physical system passed rigorous environmental tests and remained operational. A wavelength meter integrated in this physical system could monitor the wavelengths of the incident laser, and it could automatically calibrate the wavelengths of all lasers using a microcomputer. This compact and robust physical system could be a hardware basis for demonstrating a portable optical clock or even a space optical clock.
... The paper by Mohr et al. 5 explains the current state, where SI units are being bought more into the quantum measurement realm. The excellent paper by M. J. Duff et al. 6 includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
... Within the set in Table 2 are two parameters that deserve further consideration, and . The maximal value for Resistance is equal to the von Klitzing constant , (5) and the value of the Magnetic Flux is equal to twice the inverse of the Josephson constant , Table 3 shows that the NSI values of and are identical to and when translated into DAPU units by multiplying by the factor for ( (SI)) and √ for ( (SI)). To ensure clarity, new parameters will be defined (7) and (8) where and denote the DAPU interpretations of and which can be more easily compared with other constants in DAPU units. ...
This paper presents a tool kit of new ways of understanding fundamental physics and the relationships between parameters. The novel insights and predictions include: A self-contained consistent new Planck unit set of maximal-sized parameters from which all observed values can be compared and easily combined in equations. A self-contained consistent new Planck unit set of electron-charge-based parameters, some of which are directly observable in experiments. The interpretation of the gravitational constant G as a dimensionless ratio. The elimination of the need to test the equivalence of gravitational and inertial mass. That all parameters can be displayed in terms of only h and c for the Planck maximal-parameter set and additionally in alpha for the electron-charge-based set, previously considered impossible. A new dimensional analysis employed to describe parameter dimensionality and to uncover any law of nature or universal constant. That all electron-charge-based Planck parameters can be described solely in terms of ratios of Rk and Kj and so will benefit from the precision of measurement of these two parameters. That most electromagnetic parameters can be reinterpreted in terms of mechanical parameters. By adjusting currently misaligned SI units to be self-consistent and consistent with these Double-adjusted-Planck units, greater clarity will ensue.
... The paper by Mohr et al. 5 explains the current state, where SI units are being bought more into the quantum measurement realm. The excellent paper by M. J. Duff et al. 6 includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
... Within the set in Table 2 are two parameters that deserve further consideration, and . The maximal value for Resistance is equal to the von Klitzing constant , (5) and the value of the Magnetic Flux is equal to twice the inverse of the Josephson constant , Table 3 shows that the NSI values of and are identical to and when translated into DAPU units by multiplying by the factor for ( (SI)) and √ for ( (SI)). To ensure clarity, new parameters will be defined (7) and (8) where and denote the DAPU interpretations of and which can be more easily compared with other constants in DAPU units. ...
The eight Vigier Symposium held at a joint meeting with the British Computer Society - Cybernetics Machine Group (BCS-V8) at its national headquarters in Covent Garden, London, was very succesfull with about 50 delegates from dozen of countries. As the 52 chapters will reflect this symposium was a delightifull and erudite cornucopia of ideas.
The volume covers a broad spectrum of theoretical and mathematical physics by researchers from over 20 nations from four continents. Like Vigier himself, the Vigier symposia are noted for adressing avant-garde, cutting edge topics in contemporary physics.
... 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 Aether Physics Model (APM) presents a radical reinterpretation of fundamental physics, offering potential solutions to long-standing problems in Quantum Mechanics and General Relativity. This paper explores the core concepts and equations of the APM, demonstrating how they provide a unified framework for understanding the nature of space, time, matter, and fundamental forces. We examine the implications of the APM's quantized Aether structure, the role of the Singularity and Gforce, and the reinterpretation of fundamental constants and forces. The model's predictions regarding dark matter, neutron content in stable matter, and the unification of forces are discussed, along with potential experimental tests. Additionally, we introduce the loxodrome concept and toroidal particle topology as central elements in explaining fundamental particles and forces. While speculative, the APM offers a thought-provoking alternative to standard physics models and warrants further investigation.
... 9 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 Aether Physics Model (APM) presents a radical reinterpretation of fundamental physics, offering potential solutions to long-standing problems in Quantum Mechanics and General Relativity. This paper explores the core concepts and equations of the APM, demonstrating how they provide a unified framework for understanding the nature of space, time, matter, and fundamental forces. We examine the implications of the APM's quantized Aether structure, the role of the Singularity and Gforce, and the reinterpretation of fundamental constants and forces. The model's predictions regarding dark matter, neutron content in stable matter, and the unification of forces are discussed, along with potential experimental tests. Additionally, we introduce the loxodrome concept and toroidal particle topology as central elements in explaining fundamental particles and forces. While highly speculative, the APM offers a thought-provoking alternative to standard physics models and warrants further investigation.
... 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 Aether Physics Model (APM) presents a radical reinterpretation of fundamental physics, offering potential solutions to long-standing problems in Quantum Mechanics and General Relativity. This paper explores the core concepts and equations of the APM, demonstrating how they provide a unified framework for understanding the nature of space, time, matter, and fundamental forces. We examine the implications of the APM's quantized Aether structure, the role of the Singularity and Gforce, and the reinterpretation of fundamental constants and forces. The model's predictions regarding dark matter, neutron content in stable matter, and the unification of forces are discussed, along with potential experimental tests. Additionally, we introduce the loxodrome concept and toroidal particle topology as central elements in explaining fundamental particles and forces. While highly speculative, the APM offers a thought-provoking alternative to standard physics models and warrants further investigation.
... The presence of an alternative standard that was more precise threatened to make the SI irrelevant. Faced with this crisis, the SI began a long process of reinventing itself (see Taylor & Mohr 2001) leading to the reforms of 2018/2019. In the new SI (BIPM 2019) only the second is specified by a specific physical process (a spectral line in Cs). ...
... The presence of an alternative standard that was more precise threatened to make the SI irrelevant. Faced with this crisis, the SI began a long process of reinventing itself (see Taylor & Mohr, 2001) leading to the reforms of 2018/2019. In the new SI (BIPM, 2019) only the second is specified by a specific physical process (a spectral line in Cs). ...
In 2019 the International System of units (SI) conceptually re-invented itself. This was necessary because quantum-electronic devices had become so precise that the old SI could no longer calibrate them. The new system defines values of fundamental constants (including c,h,k,e but not G) and allows units to be realized from the defined constants through any applicable equation of physics. In this new and more abstract SI, units can take on new guises --- for example, the kilogram is at present best implemented as a derived electrical unit. Relevant to astronomy, however, is that several formerly non-SI units, such as electron-volts, light-seconds, and what we may call "gravity seconds" , can now be interpreted not as themselves units, but as shorthand for volts and seconds being used with particular equations of physics. Moreover, the classical astronomical units have exact and rather convenient equivalents in the new SI: zero AB magnitude amounts to photons per logarithmic frequency or wavelength interval, light-seconds, light-seconds, while a solar mass gravity-seconds. As a result, the unit conversions ubiquitous in astrophysics can now be eliminated, without introducing other problems, as the old-style SI would have done. We review a variety of astrophysical processes illustrating the simplifications possible with the new-style SI, with special attention to gravitational dynamics, where care is needed to avoid propagating the uncertainty in G. Well-known systems (GPS satellites, GW170817, and the M87 black hole) are used as examples wherever possible.
... The paper by Mohr et al. 5 explains the current state, where SI units are being bought more into the quantum measurement realm. The excellent paper by M. J. Duff et al. 6 includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper presents a tool kit for new ways of understanding fundamental physics and the relationships between
properties. The novel insights and predictions include: A self-contained consistent new adjusted-Planck unit set of
maximal-sized properties from which all observed property values can be compared and more easily combined in
equations; A self-contained consistent new adjusted-Planck unit set of electron-charge-size based properties, some of
which are directly observable in experiments; The interpretation of the Gravitational, Planck and Boltzmann constants
G, h and kB as dimensionless ratios, the former two innovatively split equally between the mass and length units; The
equivalence of the strength of charge and gravitational fields; The elimination of the need to test the equivalence of
gravitational mass and inertial mass and that all properties can be displayed in terms of only square root c for the adjusted-
Planck maximal-property set and additionally in square root (2 pi c /alpha) for the electron-charge-size based set, previously
considered impossible. A new dimensional analysis is employed to describe property dimensionality and to uncover
any law of nature or universal constant. It is shown that all electron-charge-size based adjusted-Planck properties can
be described solely in terms of ratios of the von Klitzing the Josephson constants Rk and K j
, so will benefit from
the precision of measurement of these two properties, and that most electromagnetic properties can be reinterpreted in
terms of mechanical properties. By adjusting currently misaligned SI units to be self-consistent and consistent with the
newly introduced Triple-adjusted-Planck units, greater clarity will ensue. The new dimensional analysis shows that the
current set of properties is missing two from the set, whose dimensions and probable units can be inferred.
... The paper by Mohr et al. 5 explains the current state, where SI units are being bought more into the quantum measurement realm. The excellent paper by M. J. Duff et al. 6 includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper presents new ways of understanding the relationships between parameters. The novel insights and pre-
dictions include: A self-contained and consistent new Planck unit set of maximal sized parameters from which all
observed values can be compared and easily combined in equations. A self-contained and consistent new Planck unit
set of electron-charge based parameters, some of which are directly observable in experiments. The interpretation of
the gravitational constant G as a dimensionless ratio and its relegation from gravitational to permeability use and
the elimination of the need to test the equivalence of gravitational and inertial masses. That all parameters can be
displayed in terms of only h and c for the Planck maximal parameter set and in terms of only h, c and alpha for the
electron-charge based set (other than permeability and permittivity which have G content), and which was previously
considered impossible. There exists a new hypothetical dimensional analysis that can be used to describe parame-
ter dimensions and to uncover any law of nature or any universal constants. That all electron charge based Planck
parameters can be described solely in terms of ratios of the Rk and Kj and so will benefit from the precision of mea-
surement of these two parameters. That the experimentally observed value of Rk implies either that the velocity of a
current within certain electromagnetic materials could be in excess of light speed, the patterns produced by subluminal
physical objects have a maximum velocity of 2 pi c/alpha or that such a velocity is required in order to pass through those
material. That most electromagnetic parameters can be reinterpreted in terms of mechanical parameters. By adjusting
currently misaligned SI units to be self-consistent and consistent with DAPU units, greater clarity will ensue. This is
a toolkit for providing a better understanding of the fundamentals of physics.
... The paper by Mohr et al. [1] explains the current state, where SI units are being bought more into the quantum measurement realm. The paper by M. J. Duff et al. [2] includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper shows that there are deeper symmetries within physics than are currently recognised. The use of SI units in their existing form hides that gravity is not the weakest force. The paper shows through symmetry arguments that Planck's constant h and the Gravitational constant G are both dimensionless ratios when dimensional analysis is used at property levels deeper than mass, length and time. The resultant adjustments shown to be needed for SI units produce much simpler sets of units which also solve the issue of why magnetic field H and magnetic inductance B have not previously had the same units. The result shows that gravitational and charge fields have the same strengths when considered in fractional adjusted-Planck values. By showing that h and G are dimensionless, they can be understood to be unit-dependent ratios which can be eliminated from all equations by merging them within new adjusted SI units. The implications are that mass and charge sizes, and distance, are not the properties which separate quantum and classical gravitational systems. The equivalence of gravitational and inertial mass is also shown. The new type of dimensional analysis shows how to uncover any law of nature or universal constant and that the current set of properties of nature is missing two from the set, whose dimensions and units can be inferred.
... The paper by Mohr et al. [1] explains the current state, where SI units are being bought more into the quantum measurement realm. The paper by M. J. Duff et al. [2] includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper shows that there are deeper symmetries within physics than are currently recognised. The use of SI units in their existing form hides that gravity is not the weakest force. The paper shows through symmetry arguments that Planck's constant h and the Gravitational constant G are both dimensionless ratios when dimensional analysis is used at property levels deeper than mass, length and time. The resultant adjustments shown to be needed for SI units produce much simpler sets of units which also solve the issue of why magnetic field H and magnetic inductance B have not previously had the same units. The result shows that gravitational and charge fields have the same strengths when considered in fractional adjusted-Planck values. By showing that h and G are dimensionless, they can be understood to be unit-dependent ratios which can be eliminated from all equations by merging them within new adjusted SI units. The implications are that mass and charge sizes, and distance, are not the properties which separate quantum and classical gravitational systems. And the equivalence of gravitational and inertial mass. The new type of dimensional analysis shows how to uncover any law of nature or universal constant and that the current set of properties of nature is missing two from the set, whose dimensions and units can be inferred. The article in the Journal of Mathematical Physics is missing the property power analysis included here.
... The conventional values K J−90 = 483 597:9 GHz=V and R K−90 = 25 812:807 Ω adopted in 1990 for the Josephson and von Klitzing constants established conventional units of voltage and resistance, V 90 and Ω 90 , given by V 90 = ðK J−90 =K J Þ V and Ω 90 = ðR K =R K−90 Þ Ω. Other conventional electric units follow from V 90 and Ω 90 , for example, A 90 = V 90 =Ω 90 , C 90 = A 90 s, W 90 = A 90 V 90 , F 90 = C 90 =V 90 , and H 90 = Ω 90 s, which are the conventional units of current, charge, power, capacitance, and inductance, respectively, (Taylor and Mohr, 2001). The 2014 adjustment gives for the relations between K J and K J−90 , and for R K and R K−90 , ...
This paper gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. Details of the data selection and methodology of the adjustment are described. The recommended values may also be found at http://physics.nist.gov/constants. © 2016 AIP Publishing LLC for the National Institute of Standards and Technology.
... The paper by Mohr et al. [1] explains the current state, where SI units are being bought more into the quantum measurement realm. The paper by Duff et al. [2] includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper shows that there are deeper symmetries within physics than are currently recognised. The use of SI units in their existing form hides that gravity is not the weakest force. The paper shows through symmetry arguments that Planck’s constant h and the Gravitational constant G are both dimensionless ratios when dimensional analysis is used at property levels deeper than mass, length and time. The resultant adjustments shown to be needed for SI units produce much simpler sets of units which also solve the issue of why magnetic field H and magnetic inductance B have not previously had the same units. The result shows that gravitational and charge fields have the same strengths when considered in fractional adjusted-Planck values. By showing that h and G are dimensionless, they can be understood to be unit-dependent ratios which can be eliminated from all equations by merging them within new adjusted SI units. The implications are that mass and charge sizes, and distance, are not the properties which separate quantum and classical gravitational systems. The equivalence of gravitational and inertial mass is also shown. The new type of dimensional analysis shows how to uncover any law of nature or universal constant and that the current set of properties of nature is missing two from the set, whose dimensions and units can be inferred.
... The paper by Mohr et al. 5 explains the current state, where SI units are being bought more into the quantum measurement realm. The excellent paper by M. J. Duff et al. 6 includes a broad and varied introduction to the problems of fundamental units and also covers their relationship with SI units. ...
This paper presents a tool kit of new ways of understanding fundamental
physics and the relationships between parameters. The novel insights and
predictions include: A self-contained consistent new Planck unit set of
maximal-sized parameters from which all observed values can be compared
and easily combined in equations. A self-contained consistent new Planck
unit set of electroncharge-based parameters, some of which are directly
observable in experiments. The interpretation of the gravitational
constant, G as a dimensionless ratio eliminates the need to test the
equivalence of gravitational and inertial mass. That all parameters can
be displayed in terms of only h and c for the Planck maximal-parameter
set and additionally in a for the electron-charge-based set, previously
considered impossible. A new dimensional analysis employed to describe
parameter dimensionality and to uncover any law of nature or universal
constant. That all electron-charge-based Planck parameters can be
described solely in terms of ratios of Rk and Kj
and so will benefit from the precision of measurement of these two
parameters. That most electromagnetic parameters can be reinterpreted in
terms of mechanical parameters. By adjusting currently misaligned SI
units to be self-consistent and consistent with these
Double-adjusted-Planck units, greater clarity will ensue.
... To ensure the continuity within the SI, the conventionally fixed value of h would be the generally accepted experimental value at the time of the new definition. According to propositions of Taylor and Mohr [22,23], the new definition of the kilogram could read as follows: 'The kilogram is the mass of a body at rest whose equivalent energy equals the energy of a collection of photons whose frequencies sum to 135 639 274 × 10 42 Hz', or in other words: 'One kilogram is a mass such that the Planck constant h is exactly 6.626 068 76 × 10 −34 J s'. These definitions are based on the well-known Einstein relation E = mc 2 , where c is the speed of light fixed by the definition of the metre, and the relation E = hν valid for the energy of photons. ...
Among the priority tasks in the further development of the International System of Units is the redefinition of the kilogram based on fundamental constants. One of the strategies pursued today is to relate mass to Planck's constant h using the equivalence between mechanical and electrical energies. In this paper, possible experimental approaches in this direction are described. The approach which promises to reach the required uncertainty at the earliest is the concept of the moving-coil watt balance. The status of the different watt balance experiments is reviewed in detail.
... So, today, we can consider the proposition of an overlay to the SI system, linking it more or less completely to the fundamental constants, which would allow our present understanding of the physical world and of the fundamental interactions to be better taken into consideration, and interfering as little as possible with the current system in use (Taylor & Mohr 2001;Kose et al. 2003;Moldover & Ripple 2003;Tuninsky 2003;Bordé 2004a;Bordé & Kovalevsky 2004). ...
Over the past 40 years, a number of discoveries in quantum physics have completely transformed our vision of fundamental metrology. This revolution starts with the frequency stabilization of lasers using saturation spectroscopy and the redefinition of the metre by fixing the velocity of light c. Today, the trend is to redefine all SI base units from fundamental constants and we discuss strategies to achieve this goal. We first consider a kinematical frame, in which fundamental constants with a dimension, such as the speed of light c, the Planck constant h, the Boltzmann constant k(B) or the electron mass m(e) can be used to connect and redefine base units. The various interaction forces of nature are then introduced in a dynamical frame, where they are completely characterized by dimensionless coupling constants such as the fine structure constant alpha or its gravitational analogue alpha(G). This point is discussed by rewriting the Maxwell and Dirac equations with new force fields and these coupling constants. We describe and stress the importance of various quantum effects leading to the advent of this new quantum metrology. In the second part of the paper, we present the status of the seven base units and the prospects of their possible redefinitions from fundamental constants in an experimental perspective. The two parts can be read independently and they point to these same conclusions concerning the redefinitions of base units. The concept of rest mass is directly related to the Compton frequency of a body, which is precisely what is measured by the watt balance. The conversion factor between mass and frequency is the Planck constant, which could therefore be fixed in a realistic and consistent new definition of the kilogram based on its Compton frequency. We discuss also how the Boltzmann constant could be better determined and fixed to replace the present definition of the kelvin.
The problem in defining a measurement unit in terms of an artefact is the long time constancy of the quantity contained in the artefact. Maxwell James Clark was perhaps the first scientist to oppose to defining a unit in terms of an artefact. He said “If we wish to obtain standard of length, time and mass, which shall be absolutely permanent, we must not seek them in dimension, motion, and mass of a planet but in terms of wavelength, period of vibration and the absolute mass of the imperishable and unalterable and perfectly similar molecules”. Max Planck went even further and advocated that units of measurements should be defined in terms of fundamental constants of nature instead of atoms or molecules.
In the previous chapters, we have seen a number of sets of physical constants to define a system of units. All through the efforts are being to find out a set of physical constants, which can describe all units of measurement.
By showing that the Planck and Gravitational constants are dimensionless, they can be understood to be unit-dependent ratios which can be eliminated from all equations by merging them within new adjusted SI units. This requires first that current SI units be analysed and their inconsistencies rectified. The reinterpretation of G and h implies the equivalence of the strength of charge and gravitational fields. This implies that mass and charge sizes, and distance, are not the properties which separate quantum and classical gravitational systems and eliminates the need to test the equivalence of gravitational and inertial mass. A new type of dimensional analysis is employed to describe property dimensionality, show the dimensionless nature of h and G and to uncover any law of nature or universal constant. Only by solving these existing issues in our current SI units is it possible to show that supposedly different equations describing relationships between mechanical properties and between electromagnetic properties are actually identical, allowing the reinterpretation of electromagnetic properties in terms of mechanical properties. The new dimensional analysis shows that the current set of properties of nature is missing two from the set, whose dimensions and probable units can be inferred.
A simple framework for our universe in which the basic constituents act as a background upon which actions by composite particles, composed of those same constituents in motion, act and whose presence or absence from volumes give rise respectively to relativistic and quantum systems. Where the background exists, all composite particles experience energy loss in motion due to viscosity and a maximum velocity and where the background does not exist, there is no energy loss in motion and no maximum velocity. The framework is based on the simple premises of the one size of fundamental building block, the meon, two types of energy, one composite loop form of particle and only three dimensions. Composite loops formed from the unit meon building blocks during different inflation events produce different sizes of fermions, nucleons and atoms, but produce a type of universe with symmetries similar to ours as the inevitable outcome of a successful inflation event. The rate of expansion after a big bang is a function of the size of the electron formed during inflation and that size defines whether the expansion will eventually succeed or fail. Key paradoxes are shown not to be paradoxes. This framework explains what energy and inertia are, how positive-only mass arises, spin units of ½ h, electrons with 720 o of rotation, charge unit sizes, why particles have internal magnetic moments, the second law of thermodynamics and the arrow of time, where there is a maximum speed for particles, why stable states exist, why tired light may reduce the need for dark energy or the size of the universe, why there is no matter/anti-matter imbalance, what dark matter is likely to be, the physical reality underlying zero point energy, why physics fails nowhere and why there is only one universe with threefold symmetry within our nucleons.
A pulsar time scale is considered, including possibilities for its realization and possible applications to fundamental problems in astronomy and physics.
Kilogram, the unit of mass, is the last one of seven base units in International System of Units (SI) which is still defined and kept by a material artifact. 1 kg is defined as the mass of the International Prototype of the Kilogram (IPK) kept at the Bureau International des Poids et Mesures (BIPM) in Paris. One of the major disadvantages of this definition is the fact that the amount of material constituting the IPK changes with time. Because a more stable mass reference does not exist, the variation of IPK is completely unknown so far. The International Committee for Weights and Measures (CIPM) recommended redefining the kilogram by fixing the numerical value of the Planck constant h and called on every national metrology institute to study the measurement of the h. To avoid possible system errors from one method, more experiments especially based on different principles are expected and encouraged for the final determination of the Planck constant. The CCM required that at least three consistent results should be obtained before the redefinition. Since 1970 s, the Kibble balance (also known as the Kibble balance) experiment has been used by a number of national metrology institutes such as NPL, NIST, METAS, LNE and BIPM. The IAC including the PTB, NMIJ and NMIA used the XRCD method to measure the Avogadro constant. To make contribution to the redefinition of kilogram, the National Institute of Metrology of China (NIM) proposed a joule balance method in 2006, which is also an electrical way but different from the watt balance method in that the dynamic phase is replaced with a static phase to avoid the trouble in the dynamic measurement. The progress of these approaches and the current situation of the redefinition of the kilogram are presented in this paper. In 2013, a model apparatus was built to verify the principle of the joule balance. Then NIM started to build its new joule balance aiming to obtain an uncertainty of 10⁻⁸ level since 2013. In Dec. 2016, the new apparatus was built and could be used to measure the Planck constant h in vacuum. In May 2017, the measurement result was submitted to the Metrologia and accepted by the CODATA TGFC as the input data. However, the measurement result has an uncertainty bigger than 10⁻⁸ and was not used for the final determination of the h value. At present, the joule balance group of NIM, together with the Harbin Institute of Technology, Tsinghua University and China Jiliang University is still making great efforts to improve the joule balance apparatus. The uncertainty of 10⁻⁸ level is expected to be achieved in the next two years.
The AC-DC magnetic field standard systems were constructed for the calibration of magnetometers for low magnetic field and the tests for low magnetic field characteristics of sensors and materials. In the range of 1 mT, the expanded uncertainty of dc is 8{\times}10\^-6/, ac uncertainties are 0.16% in 0.1?1 kHz, 0.26% in 1?5 kHz, and 0.44% in 5?20 kHz. We have been participated in international key comparison(KC) to achieve the equality and the mutual agreement between standard institutes for the results of calibrations and tests. KRISS participating in ac-dc magnetic flux density of KC got equal level of uncertainty results compare with the advanced nations. It confirm that measurement ability of magnetic flux density is high level in the world.
In the present chapter, a glimpse has been given about futuristic view on definitions of base units of the international system of units SI. Methods of defining base units in terms of physical constants of one element namely hydrogen one standard namely frequency indestructible and invariable physical constants some invariant physical phenomenon like Einstein matter energy relation have been discussed. The latest thinking about redefinitions of kilogram, ampere, kelvin and mole have also been discussed
This paper gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. Details of the data selection and methodology of the adjustment are described. The recommended values may also be found at physics.nist.gov/constants.
This paper presents a new method to measure the constant h/e based on optical measurements at room temperature. This could be a new quantum voltage standard alternative to present Josephson system.
Published in: 2016 Conference on Precision Electromagnetic Measurements (CPEM 2016)
Our purpose is to offer a logical analysis of the system of units and to explore possible paths towards a consistent and unified system with an original perspective. The path taken here builds on the fact that, thanks to optical or matter-wave interferometry, any measurement can be reduced to a dimensionless phase measurement and we follow this simple guiding line. We finally show how one could progress even further on the path of a synthetic framework for fundamental metrology based upon pure geometry in five dimensions.
The problem in defining a measurement unit in terms of an artefact is the long time constancy of the quantity contained in the artefact. Maxwell James Clark was perhaps the first scientist to oppose to defining a unit in terms of an artefact. He said “If we wish to obtain standard of length, time and mass, which shall be absolutely permanent, we must not seek them in dimension, motion, and mass of a planet but in terms of wavelength, period of vibration and the absolute mass of the imperishable and unalterable and perfectly similar molecules”. Max Planck went even further and advocated that units of measurements should be defined in terms of fundamental constants of nature instead of atoms or molecules.
This paper presents a kind of axisymmetric coil system with novel dimension scale aiming at Joule balance that is used to define the quantum mass standard and is lately paid more attention to. Analytical modeling and numerical computation show that an annular homogeneous magnetic field with 2 cm axial length will exist in the symmetrical plane of the magnetic system of Joule balance through reasonably configure the geometrical parameters of the axisymmetric coil system. The conditions are that the distance between the inner and outer exciting coils R and the distance between exciting coils and suspended coil H satisfy the equation R2=4/3H2, and the ratio of the number of turns of inner, outer exciting coils and suspended coil satisfies the requirement of 10000:2700:430. In the annular homogeneous magnetic field, mutual inductance M possesses forth order homogeneity, which satisfies the requirement of accurate measurement of mutual inductance M.
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.
The various features and future prospects of the International System of Units (SI) are described. The SI is based on seven selected base units, corresponding to the seven quantities such as length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Fundamental metrology faces the anomalous situation, in which the realization of the SI electrical units is difficult to perform according to their SI definitions, although new highly reproducible quantum standards are available, allowing the National Metrology Institutes the use of practical units of voltage and resistance. From time to time, mathematical considerations give rise to change proposals, such as introduction of the number 1 as an SI unit.
The International System of Units (SI) is founded on seven base units, the metre, kilogram, second, ampere, kelvin, mole and candela corresponding to the seven base quantities of length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity. At its 94th meeting in October 2005, the International Committee for Weights and Measures (CIPM) adopted a recommendation on preparative steps towards redefining the kilogram, ampere, kelvin and mole so that these units are linked to exactly known values of fundamental constants. We propose here that these four base units should be given new definitions linking them to exactly defined values of the Planck constant h, elementary charge e, Boltzmann constant k and Avogadro constant NA, respectively. This would mean that six of the seven base units of the SI would be defined in terms of true invariants of nature. In addition, not only would these four fundamental constants have exactly defined values but also the uncertainties of many of the other fundamental constants of physics would be either eliminated or appreciably reduced. In this paper we present the background and discuss the merits of these proposed changes, and we also present possible wordings for the four new definitions. We also suggest a novel way to define the entire SI explicitly using such definitions without making any distinction between base units and derived units. We list a number of key points that should be addressed when the new definitions are adopted by the General Conference on Weights and Measures (CGPM), possibly by the 24th CGPM in 2011, and we discuss the implications of these changes for other aspects of metrology.
The objective of this paper is to provide general principles that should guide any future discussions regarding the redefinition of the SI base units. The suggestion is to use the envisaged redefinition of the unit of mass, the kilogram, as an opportunity to generally check the compliance of all base units with modern demands and the needs of economy, science and society. In order to meet these requirements it is proposed principally to separate the 'carrier' of the definition and the 'carriers' of the realization of the SI units. By providing an example of a revised SI it is shown that these considerations could add value to the International System of Units.
This paper gives the 2002 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 subset of constants on which the complete 2002 set of recommended values is based. Two noteworthy additions in the 2002 adjustment are recommended values for the bound-state rms charge radii of the proton and deuteron and tests of the exactness of the Josephson and quantum-Hall-effect relations and , where and are the Josephson and von Klitzing constants, respectively, e is the elementary charge, and h is the Planck constant. The 2002 set replaces the previously recommended 1998 CODATA set. The 2002 adjustment takes into account the data considered in the 1998 adjustment as well as the data that became available between 31 December 1998, the closing date of that adjustment, and 31 December 2002, the closing date of the new adjustment. The differences between the 2002 and 1998 recommended values compared to the uncertainties of the latter are generally not unreasonable. The new CODATA set of recommended values may also be found on the World Wide Web at physics.nist.gov/constants.
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 would accrue if the kilogram were redefined so as to fix the value of either the Planck constant h or the Avogadro constant NA instead of m(K), without waiting for the experiments to determine h or NA 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.
We have re-analyzed the stability of pulse arrival times from pulsars and
white dwarfs using several analysis tools for measuring the noise
characteristics of sampled time and frequency data. We show that the best
terrestrial artificial clocks substantially exceed the performance of
astronomical sources as time-keepers in terms of accuracy (as defined by cesium
primary frequency standards) and stability. This superiority in stability can
be directly demonstrated over time periods up to two years, where there is high
quality data for both. Beyond 2 years there is a deficiency of data for
clock/clock comparisons and both terrestrial and astronomical clocks show equal
performance being equally limited by the quality of the reference timescales
used to make the comparisons. Nonetheless, we show that detailed accuracy
evaluations of modern terrestrial clocks imply that these new clocks are likely
to have a stability better than any astronomical source up to comparison times
of at least hundreds of years. This article is intended to provide a correct
appreciation of the relative merits of natural and artificial clocks. The use
of natural clocks as tests of physics under the most extreme conditions is
entirely appropriate; however, the contention that these natural clocks,
particularly white dwarfs, can compete as timekeepers against devices
constructed by mankind is shown to be doubtful.
This paper gives the 2010 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.
The 2010 adjustment takes into account the data considered in the 2006
adjustment as well as the data that became available from 1 January 2007, after
the closing date of that adjustment, until 31 December 2010, the closing date
of the new adjustment. 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 2010 set replaces the
previously recommended 2006 CODATA set and may also be found on the World Wide
Web at physics.nist.gov/constants.
A capacitance standard based directly on the definition of capacitance was built. Single-electron tunneling devices were used to place N electrons of charge e onto a cryogenic capacitor C, and the resulting voltage change DeltaV was measured. Repeated measurements of C = Ne/DeltaV with this method have a relative standard deviation of 0.3 x 10(-6). This standard offers a natural basis for capacitance analogous to the Josephson effect for voltage and the quantum Hall effect for resistance.
We have developed a prototype of a new capacitance standard based on a
direct implementation of the definition of capacitance. We use
single-electron tunneling devices to place a known number of electrons
onto a cryogenic, vacuum-gap capacitor, and measure the resulting
voltage to determine C. The uncertainty in the value of C is presently
less than 1 parts per million and an uncertainty of about 0.01 ppm
appears possible with further refinement of the technique. The new
standard offers potential advantages analogous to the Josephson voltage
standard and the quantum Hall resistance standard, i.e., a quantum
standard that can be replicated with relative ease at many locations and
which reduces the need for artifact calibrations by NIST. We are
constructing an automated and portable version of the standard that will
allow us to demonstrate these advantages to potential users in
industrial and government calibration labs.
We have operated a 7‐junction electron pump as an electron counter with an error per pumped electron of 15 parts in 109 and an average hold time of 600 s. The accuracy and hold time are sufficient to enable a new fundamental standard of capacitance. We compare the measured accuracy of the pump as a function of pumping speed and temperature with theoretical predictions based on a model which includes stray capacitance.
We give here the background and basis for the new international electrical reference standards of voltage and resistance that are to come into effect worldwide starting on 1st January 1990. Founded on the Josephson and quantum Hall effects, respectively, these new reference standards will improve significantly the international uniformity of electrical measurements and their consistency with the SI.
This paper gives the 1998 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 subset of constants on which the complete 1998 set of recommended values is based. The 1998 set replaces its immediate predecessor recommended by CODATA in 1986. The new adjustment, which takes into account all of the data available through 31 December 1998, is a significant advance over its 1986 counterpart. The standard uncertainties (i.e., estimated standard deviations) of the new recommended values are in most cases about 1/5 to 1/12 and in some cases 1/160 times the standard uncertainties of the corresponding 1986 values. Moreover, in almost all cases the absolute values of the differences between the 1998 values and the corresponding 1986 values are less than twice the standard uncertainties of the 1986 values. The new set of recommended values is available on the World Wide Web at physics.nist.gov/constants.
Summary form only given. The author discusses the possibility of
certain fundamental physical constants replacing the current unit of
mass in the International System of Units. These constants include the
Rydberg, fine-structure, Josephson, and von Klitzing constants, the
atomic mass of the proton, and the proton-electron mass ratio