earlier reported shell model calculation. The pn-QRPA results for $^{57}$Zn were in good agreement with the experimental results [@Jokinen02] and reproduced well the measured GT strength between 2-3 MeV. The stellar weak decay rates are sensitive to the location and structure of these low-lying states in daughter $^{57}$Cu. Small changes in the binding and excitation energies can lead to significant modifications of the predictions for the synthesis of proton-rich isotopes. The primary mechanism for the production of the proton-rich nuclei is the rp-process and is believed to be important in the dynamics of the collapsing supermassive stars. The good agreement of the reported low-lying GT strength with the experimental results validates the choice of the pn-QRPA theory as a preferred model for the calculation of weak rates for proton-rich nuclei. The choice of nuclear model can affect the prediction and synthesis of proton-rich isotopes as well as the time evolution of the cosmic x-ray burst and dynamics of the collapsing supermassive stars. For comparison, in the present work we obtained a summed B(GT) of 1.86 as compared to 1.25 in Ref. [@Jokinen02] within the excitation energy interval between 0 and 7 MeV in daughter $^{57}$Cu. The shell model predicted strength 