A gas turbine engine comprising: a first spool comprising a first compressor rotationally driven by a first turbine via a first shaft ; a primary combustor ; a diffuser having walls that diverge towards the primary combustor , wherein the first compressor , the diffuser , and the primary combustor are arranged in series to provide a compressed airflow discharged from the first compressor to the primary combustor via the diffuser ; a second spool comprising a second compressor rotationally driven by a second turbine via a second shaft ; a secondary combustor disposed downstream from the second compressor and upstream from the second turbine , wherein: the second compressor is fluidly coupled to the diffuser to receive at least a portion of the compressed airflow from the diffuser ; the second compressor , the secondary combustor , and the second turbine are arranged in series to provide a compressed boost airflow discharged from the second compressor to the secondary combustor and a combusted boost airflow from the secondary combustor to the second turbine ; and the second turbine is fluidly coupled to the diffuser to discharge an expanded airflow to the diffuser , characterized in that the engine further comprises: a first motor generator mechanically connected to the first shaft of the first spool ; and a second motor generator mechanically connected to the second shaft of the second spool , wherein the first motor generator is electrically coupled to the second motor generator;. a first spool comprising a first compressor rotationally driven by a first turbine via a first shaft ; a primary combustor ; a diffuser having walls that diverge towards the primary combustor , wherein the first compressor , the diffuser , and the primary combustor are arranged in series to provide a compressed airflow discharged from the first compressor to the primary combustor via the diffuser ; a second spool comprising a second compressor rotationally driven by a second turbine via a second shaft ; a secondary combustor disposed downstream from the second compressor and upstream from the second turbine , wherein: the second compressor is fluidly coupled to the diffuser to receive at least a portion of the compressed airflow from the diffuser ; the second compressor , the secondary combustor , and the second turbine are arranged in series to provide a compressed boost airflow discharged from the second compressor to the secondary combustor and a combusted boost airflow from the secondary combustor to the second turbine ; and the second turbine is fluidly coupled to the diffuser to discharge an expanded airflow to the diffuser , the second compressor is fluidly coupled to the diffuser to receive at least a portion of the compressed airflow from the diffuser ; the second compressor , the secondary combustor , and the second turbine are arranged in series to provide a compressed boost airflow discharged from the second compressor to the secondary combustor and a combusted boost airflow from the secondary combustor to the second turbine ; and the second turbine is fluidly coupled to the diffuser to discharge an expanded airflow to the diffuser , characterized in that the engine further comprises: a first motor generator mechanically connected to the first shaft of the first spool ; and a second motor generator mechanically connected to the second shaft of the second spool , wherein the first motor generator is electrically coupled to the second motor generator;. a first motor generator mechanically connected to the first shaft of the first spool ; and a second motor generator mechanically connected to the second shaft of the second spool , wherein the first motor generator is electrically coupled to the second motor generator;. <EOS>