Dynamical generation of Floquet Majorana flat bands in s-wave superconductors
1 Department of Physics and Astronomy, Dartmouth College - 6127 Wilder Laboratory, Hanover, NH 03755, USA
2 Department of Physics, Indiana University - Bloomington, IN 47405, USA
Received: 6 December 2014
Accepted: 24 March 2015
We present quantum control techniques to engineer flat bands of symmetry-protected Majorana edge modes in s-wave superconductors. Specifically, we show how periodic control may be employed for designing time-independent effective Hamiltonians, which support Floquet Majorana flat bands, starting from equilibrium conditions that are either topologically trivial or only support a Majorana pair per edge. In the first approach, a suitable modulation of the chemical potential simultaneously induces Majorana flat bands and dynamically activates a pre-existing chiral symmetry which is responsible for their protection. In the second approach, the application of effective parity kicks dynamically generates a desired chiral symmetry by suppressing chirality-breaking terms in the static Hamiltonian. Our results demonstrate how the use of time-dependent control enlarges the range of possibilities for realizing gapless topological superconductivity, potentially enabling access to topological states of matter that have no known equilibrium counterpart.
PACS: 73.20.At – Surface states, band structure, electron density of states / 74.40.Gh – Nonequilibrium superconductivity / 74.78.-w – Superconducting films and low-dimensional structures
© EPLA, 2015