Correction to: npj Quantum Information https://doi.org/10.1038/s41534-021-00449-4, published online 16 July 2021

The original version of this Article contained errors in Equation (15) and (16), in which the expressions for εA and εB 2QSS were mistakenly given in place of εmA and εmB 2QSS

$$\begin{array}{ll}\frac{{t_{{{{\mathrm{lA}}}}}}}{{t_{{{{\mathrm{rA}}}}}}} = \sqrt {\left( { - \frac{{C_{51} - C_{11}}}{{C_{21} - C_{11}}}} \right)\left( {\frac{{\frac{2}{{\left( {U - U{^\prime}{^\prime} + 2\varepsilon _{{{\mathrm{A}}}}} \right)^3}} - \frac{1}{{\left( {U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{{{{\mathrm{mA}}}}} + \varepsilon _{{{\mathrm{A}}}}} \right)^3}}}}{{\frac{2}{{\left( {U - U{^\prime}{^\prime} - 2\varepsilon _{{{\mathrm{A}}}}} \right)^3}} - \frac{1}{{\left( {U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{{{{\mathrm{mA}}}}} - \varepsilon _{{{\mathrm{A}}}}} \right)^3}}}}} \right)} ,\\\qquad \quad \left( {\varepsilon _{{{{\mathrm{mA}}}}}2{{{\mathrm{QSS}}}}} \right),\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\left({15} \right)\end{array}$$
$$\begin{array}{ll}\frac{{t_{{{{\mathrm{lB}}}}}}}{{t_{{{{\mathrm{rB}}}}}}} = \sqrt {\left( { - \frac{{C_{13} - C_{11}}}{{C_{14} - C_{11}}}} \right)\left( {\frac{{\frac{2}{{\left( {U - U{^\prime}{^\prime} + 2\varepsilon _{{{\mathrm{B}}}}} \right)^3}} - \frac{1}{{\left( {U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{{{{\mathrm{mB}}}}} + \varepsilon _{{{\mathrm{B}}}}} \right)^3}}}}{{\frac{2}{{\left( {U - U{^\prime}{^\prime} - 2\varepsilon _{{{\mathrm{B}}}}} \right)^3}} - \frac{1}{{\left( {U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{{{{\mathrm{mB}}}}} - \varepsilon _{{{\mathrm{B}}}}} \right)^3}}}}} \right)} ,\\ \qquad \quad \left( {\varepsilon _{{{{\mathrm{mB}}}}}\,2{{{\mathrm{QSS}}}}} \right).\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad \left( {16} \right)\end{array}$$

The correct forms of Eqs. (15) and (16) are:

$$\frac{{t_{lA}}}{{t_{rA}}} = \sqrt {\frac{{C_{51} - C_{11}}}{{C_{21} - C_{11}}}} \left( {\frac{{U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{mA} - \varepsilon _A}}{{U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{mA} + \varepsilon _A}}} \right)^{3/2},\quad \quad \left( {\varepsilon _{{{{\mathrm{mA}}}}}2{{{\mathrm{QSS}}}}} \right),$$
(15)
$$\frac{{t_{lB}}}{{t_{rB}}} = \sqrt {\frac{{C_{13} - C_{11}}}{{C_{14} - C_{11}}}} \left( {\frac{{U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{mB} - \varepsilon _B}}{{U - 2U^\prime + U{^\prime}{^\prime} - \varepsilon _{mB} + \varepsilon _B}}} \right)^{3/2},\quad \quad \left( {\varepsilon _{{{{\mathrm{mB}}}}}2{{{\mathrm{QSS}}}}} \right),$$
(16)

This has been corrected in both the PDF and HTML versions of the Article.