Universal Nonequilibrium Signatures of Majorana Zero Modes in Quench Dynamics

作者：Vasseur R^*; Dahlhaus J P; Moore J E

来源：Physical Review X, 2014, 4(4): 041007.

DOI：10.1103/PhysRevX.4.041007

The quantum evolution that occurs after a metallic lead is suddenly connected to an electron system contains information about the excitation spectrum of the combined system. We exploit this type of "quantum quench" to probe the presence of Majorana fermions at the ends of a topological superconducting wire. We obtain an algebraically decaying overlap (Loschmidt echo) L(t) = vertical bar vertical bar(2) similar to t(-alpha) for large times after the quench, with a universal critical exponent alpha = 1/4 that is found to be remarkably robust against details of the setup, such as interactions in the normal lead, the existence of additional lead channels, or the presence of bound levels between the lead and the superconductor. As in recent quantum-dot experiments, this exponent could be measured by optical absorption, offering a new signature of Majorana zero modes that is distinct from interferometry and tunneling spectroscopy.

• 出版日期2014-10-14