The Publisher apologises that due to a typesetting error all instances of μ were rendered as m in Tables 2 and 5, making the units of some entries incorrect by a factor of 103.
Additionally, there are missing minus signs in equations (5) and (7) in Tables 2 and 5, as well as in the table notes of Tables 3 and 4. The correct equations are:
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_eqn1.png?pub-status=live)
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_eqn2.png?pub-status=live)
The correct tables are as below
Table 2. The Planck frequency comb with ${\hbar} \rightarrow h$
$n_{h, \alpha } =\log {( E/\sqrt {hc^5/G}) }/ \! \log {( e^2/( ch) ) }$.
This set contains no convenient lines in the optical or near-infrared.
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_tab2.png?pub-status=live)
Table 3. The Planck frequency comb with $\hbar \rightarrow h$ and base e
$n_{h, e} =-\ln {( E/\sqrt {hc^5/G}) }$.
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_tab3.png?pub-status=live)
Table 4. The Planck frequency comb with base e
$n_{\hbar, e} =- \ln {( E/E_{\rm P}) }$.
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_tab4.png?pub-status=live)
Table 5. The Rydberg frequency comb $n_{R} = \log _\alpha {( E/( m_{\rm e}c^2/2) ) }$.
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20211130100009127-0588:S1473550420000324:S1473550420000324_tab5.png?pub-status=live)