Charge qubits based on ultra-thin topological insulator films

Abstract

We study how to use the surface states in a Bi${}_2$Se${}_3$ topological insulator ultra-thin film that are affected by finite size effects for the purpose of quantum computing. We demonstrate that: (i) surface states under the finite size effect can effectively form a two-level system where their energy levels lie in between the bulk energy gap and a logic qubit can be constructed, (ii) the qubit can be initialized and manipulated using electric pulses of simple forms, (iii) two-qubit entanglement is achieved through a $\sqrt{\text{SWAP}}$ operation when the two qubits are in a parallel setup, and (iv) alternatively, a Floquet state can be exploited to construct a qubit and two Floquet qubits can be entangled through a Controlled-NOT operation. The Floquet qubit offers robustness to background noise since there is always an oscillating electric field applied, and the single qubit operations are controlled by amplitude modulation of the oscillating field, which is convenient experimentally.

12 pages, 9 figures, submitted to the journal Frontiers of Physics

References in corpus (6)

• Photovoltaic Hall effect in graphene
• Scattering Theory for Floquet-Bloch States
• Weak localization and weak anti-localization in topological insulators
• Optical response of a topological-insulator--quantum-dot hybrid interacting with a probe electric field
• Low temperature saturation of phase coherence length in topological insulators
• Entanglement generation via power-of-SWAP operations between dynamic electron-spin qubits