Abstract
Optical control of chirality in chiral superconductors bears potential for future topological quantum computing applications. When a chiral domain is written and erased by a laser spot, the Majorana modes around the domain can be manipulated on ultrafast time scales. Here we study topological superconductors with two chiral order parameters coupled via light fields by a time-dependent real-space Ginzburg-Landau approach. Continuous optical driving, or the application of supercurrent, hybridizes the two chiral order parameters, allowing one to induce and control the superconducting state beyond what is possible in equilibrium. We show that superconductivity can even be enhanced if the mutual coupling between two order parameters is sufficiently strong. Furthermore, we demonstrate that short optical pulses with spot size larger than a critical one can overcome a counteracting diffusion effect and write, erase, or move chiral domains. Surprisingly, these domains are found to be stable, which might enable optically programmable quantum computers in the future.
Highlights
Chiral superconductors spontaneously break time-reversal symmetry and host topologically protected chiral Majorana edge modes [1,2], bearing potential for applications in quantum computing [3,4]
Phenomenological GL approaches solely rely on system symmetry and do not strongly depend on the underlying mechanism for chiral superconductivity [21]
The parameters therein depend on the environment such as the substrate and phonons, which may play a role in the superconducting mechanism [61,62] and, as bosonic and fermionic baths, can influence the switching processes
Summary
Chiral superconductors spontaneously break time-reversal symmetry and host topologically protected chiral Majorana edge modes [1,2], bearing potential for applications in quantum computing [3,4]. Our TDGL theory phenomenologically but transparently describes the dynamics of coupled order parameters of general chiral superconductors in both spatially homogeneous and inhomogeneous scenarios. Size switching can be obtained in a stable fashion, allowing for the optical creation or annihilation of chiral domains of multicomponent superconductors [10,21], such as the widely studied chiral p ± ip superconductivity. Since the induced chiral domain is stable after application of optical pulses, manipulation of Majorana modes at the boundary of such domains is possible This could be used to optically program quantum logic gates. Our theory transparently describes the coupling of order parameter components via an optical field, addresses the conditions of optical enhancement of chiral superconductivity, reveals the necessary conditions for local switching of chirality, and elevates the concept introduced in Ref. Our theory transparently describes the coupling of order parameter components via an optical field, addresses the conditions of optical enhancement of chiral superconductivity, reveals the necessary conditions for local switching of chirality, and elevates the concept introduced in Ref. [10] towards the functionalities of quantum gates
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