Abstract
The natural unit system, in which the value of fundamental constants such as c and ℏ are set equal to one and all quantities are expressed in terms of a single unit, is usually introduced as a calculational convenience. However, we demonstrate that this system of natural units has a physical justification as well. We discuss and review the natural units, including definitions for each of the seven base units in the International System of Units (SI) in terms of a single unit. We also review the fundamental constants, which can be classified as units-dependent or units-independent. Units-independent constants, whose values are not determined by human conventions of units, may be interpreted as inherent constants of nature.
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Another method of deciding a truly fundamental and inherent constant of nature is that it must have the same value in both inertial and non-inertial frames. The result of this method is consistent with our discussion in this paper. The reason for this method is that all physically realizable frames of reference are, strictly speaking, non-inertial because of the long-ranged gravitational force and the accelerated cosmic expansion. Inertial frames are idealized frames when the accelerations of non-inertial frames approach zero. For a discussion of accelerated frames and the Wu transformations of space-time, see the appendix of L. Hsu, J.P. Hsu, Nuovo Cimento B, 112, 1147 (1997), J.P. Hsu, D. Fine, Int. J. Mod. Phys. A. 20, 7485 (2005), J.P. Hsu, Chin. J. Phys. 40, 265 (2002)
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Hsu, L., Hsu, J.P. The physical basis of natural units and truly fundamental constants. Eur. Phys. J. Plus 127, 11 (2012). https://doi.org/10.1140/epjp/i2012-12011-5
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DOI: https://doi.org/10.1140/epjp/i2012-12011-5
Keywords
- Natural Unit
- Fundamental Constant
- Thermodynamic Temperature
- Luminous Intensity
- Planck Unit