Nuclear mass prediction using bidirectional recurrent neural networks with isotopic and isotonic chain correlations
Nuclear masses are fundamental quantities in nuclear physics, providing essential information for understanding nuclear structure, decay properties, and reaction processes. Here we develop a bidirectional recurrent neural network (Bi-RNN) that naturally incorporates sequential correlations along isotopic and isotonic chains for nuclear mass prediction. The model achieves a root-mean-square (rms) deviation of 78 keV for binding energies of 2339 nuclei with known masses, a 45% improvement over a conventional artificial neural network (ANN) with comparable parameter count. The Bi-RNN also delivers consistent accuracy across different odd-even parity groups and yields an rms of 99 keV for $Q_β$ values without explicit training, demonstrating that recurrent correlations encode physically relevant information beyond individual nuclear features. Extrapolation tests on 292 nuclei updated from AME2003 to AME2012 and on 109 nuclei updated from AME2012 to AME2020 reveal that the Bi-RNN maintains stable performance, substantially outperforming WS4, ANN, and earlier AME evaluations. These results demonstrate the power of recurrent architectures in capturing correlations along nuclear chains and suggest Bi-RNN as a robust tool for studying nuclear masses.