No magic and the same photons, but you can have the hardware sensor read them out differently. Specifically using varying amounts of analog gain / amplification before doing analog-to-digital conversion, minimizing noise. This varies based on camera design.
The article mentions the Sony A7S as an example, with the sensor showing marked improvements in SNR when reaching ISO 100, 200, 1600 and 3200, while behaving ISO-invariant wrt. noise in between those values.
See the "ISO-Invariance and Downstream Electronic Noise" part here for a better explanation: https://www.lonelyspeck.com/how-to-find-the-best-iso-for-ast...
The article mentions the Sony A7S as an example, with the sensor showing marked improvements in SNR when reaching ISO 100, 200, 1600 and 3200, while behaving ISO-invariant wrt. noise in between those values.