Giant Shot Noise from Majorana Zero Modes in Topological Trijunctions

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Mesoscopic Physics

Background:

• Experimental identification of Majorana bound states in transport measurements is difficult.
• Topological superconductors offer a platform for hosting Majorana states.
• Understanding the transport signatures of Majorana states is crucial for their detection.

Purpose of the Study:

• To identify a direct experimental signature of Majorana bound states.
• To investigate the role of Majorana states in transport measurements, specifically shot noise.
• To determine the conditions under which Majorana states influence shot noise.

Main Methods:

• Theoretical analysis of a junction of three topological superconductor wires.
• Focus on zero-energy states formed at the junction.
• Investigation of shot noise amplitudes as a function of voltage and contact transparency.

Main Results:

• The zero-energy Majorana state is directly responsible for giant shot noise amplitudes.
• This effect is particularly pronounced at low voltages.
• Small contact transparency further enhances the observed shot noise signature.

Conclusions:

• Giant shot noise is a direct and measurable consequence of Majorana bound states.
• This finding provides a new pathway for the experimental identification of Majorana states.
• Current-induced dephasing from multiple Andreev reflections is the intrinsic noise limitation.