Local master equations bypass the secular approximation

Master equations are a vital tool to model heat flow through nanoscale thermodynamic systems. Most practical devices made up of interacting sub-system, and often modelled using either local master (LMEs) or global (GMEs). While the limiting cases in which LME GME breaks down well understood, there exists 'grey area' both capture steady-state currents reliably, but predict very different transient flows. In such cases, one should we trust? Here, show that, when it comes dynamics, approach can be more reliable than for weakly open quantum This is due fact that secular approximation, underpins GME, destroy key dynamical features. To illustrate this, consider minimal transport setup its displays exceptional points (EPs). These singularities have been observed superconducting-circuit realisation [1]. However, stark contrast experimental evidence, no EPs appear within approach. We then feature built into Redfield equation, accurate GME. Finally, emerges as weak-interaction limit entirely avoids approximation.