Quantized conductance plateaus, a celebrated hallmark of Majorana bound states (MBSs) predicted a decade ago, have recently been observed with small deviations in iron-based superconductors and hybrid nanowires. Here, we demonstrate that nearly quantized conductance plateaus can also arise from trivial Andreev bound states (ABSs). To avoid ABS interruptions, we propose identifying ABS-induced quantized conductance plateaus by measuring the associated differential current noise $P$ versus bias voltage $V$. Specifically, for a quantized conductance plateau induced by one or multiple low-energy ABSs, the associated $P\left(V\right)$ curve exhibits a double-peak around zero bias, with the peak positions at $e\left|V\right|\approx 3k_{B}T$ (where $T$ is the temperature) and peak values larger than $2e^3/h$. These features greatly contrast those of an MBS or quasi-MBS, whose $P\left(V\right)$ curve displays a broad zero-bias dip and is consistently below $2e^3/h$. This protocol can be practically implemented in a variety of MBS candidate platforms using an electrode or STM tip as a probe.

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• Andreev reflection
• Majorana bound states
• Shot noise
• Topological superconductors
• S-matrix method in transport