For decades, thermoelectric devices have carried the quiet promise of turning wasted heat into useful energy, yet the tools to truly understand them have remained incomplete. A researcher at Saitama University has now built a theoretical framework that treats these devices not as isolated materials but as living systems — where electrodes, heat loss, and electrical signals are all part of one conversation. By listening carefully to how a device responds to a pulse of current over time, Yasuhiro Hasegawa found a way to separate what was once an indecipherable tangle of signals, and discovered b