Extracting entangled qubits from Majorana fermions in quantum dot chains through the measurement of parity

Abstract

We propose a scheme for extracting entangled charge qubits from quantum-dot chains that support zero-energy edge modes. The edge mode is composed of Majorana fermions localized at the ends of each chain. The qubit, logically encoded in double quantum dots, can be manipulated through tunneling and pairing interactions between them. The detailed form of the entangled state depends on both the parity measurement (an even or odd number) of the boundary-site electrons in each chain and the teleportation between the chains. The parity measurement is realized through the dispersive coupling of coherent-state microwave photons to the boundary sites, while the teleportation is performed via Bell measurements. Our scheme illustrates localizable entanglement in a fermionic system, which serves feasibly as a quantum repeater under realistic experimental conditions, as it allows for finite temperature effect and is robust against disorders, decoherence and quasi-particle poisoning.

Majorana wave-function oscillations, fermion parity switches, and disorder in Kitaev chains

“…In these systems, the Kitaev chain forming the basis of our work provides an excellent prototype and we expect our observations on Majorana oscillations and parity switches to be directly applicable. A possible avenue for exploring parity effects would involve coupling the Majorana wire to a charge sensitive system, such as a quantum dot, a single electron transistor, or a scanning tunneling microscope(STM) tip 25,89,[98][99][100][101][102] . Other methods which have gained prominence in the Majorana mode context include coupling to microwave cavity, circuit quantum electrodynamics, cooper pair boxes and Transmon systems seem to show promise and have gained much attention, especially as they directly couple to the parity sectors arising from the Majorana modes 92,[103][104][105][106][107][108][109] .…”

Majorana quasiparticles of an inhomogeneous Rashba chain

“…These emergent Majorana-type objects have been predicted in various systems, such as topological insulators 4,5 , semiconducting nanowires 6,7 , ferromagnetic chains coupled to s-wave superconducting reservoirs 8 etc. Their possible realizations have been also considered in topological superconductors with electrostatic defects 9 , Josephson type junctions 10 , quantum dot chains [11][12][13] , noncentrosymmetric superconductors 14 , ultracold atom systems 15 and many other. Intensive studies of the Majorana quasiparticles have been overviewed by several authors [16][17][18][19][20][21] .…”

Majorana bound states in a disordered quantum dot chain

“…Majorana bound states (MBSs) [1,2] in solid-state systems are recently attracting increasing interest, both theoretically and experimentally. Proposed by Kitaev more than ten years ago in a spinless toy model [1], these zero-energy bound states are expected to exist in several structures with spin, including nanowires with spinorbit coupling (SOC) in proximity to a superconductor (SC) [3][4][5], ferromagnetic atom chains on top of a SC [6], topological insulator/SC hybrid structures [7][8][9][10][11][12], quantum dot (QD) chains with SC in adjacence [13][14][15], as well as cold-atom systems [16]. Experimentally, possible signatures of MBS have been reported in nanowires [17][18][19], atom chains [20], and topological insulator/SC structures [21].…”