When pop and R&B’s biggest stars look for inspiration, they turn to Stargate. The Norwegian duo of Tor E. Hermansen and Mikkel S. Eriksen has penned some of the 21st century’s most memorable hits, dominating the charts with inspiring songs of triumph and sorrow, whether it’s an empowering anthem from Katy Perry, an exhilarating come-on from Rihanna, or a tearful ballad from Sam Smith.