Entangling spins in double quantum dots and Majorana bound states

Abstract

We study the coupling between a singlet-triplet qubit realized in a double quantum dot to a topological qubit realized by spatially well-separated Majorana bound states. We demonstrate that the singlet-triplet qubit can be leveraged for readout of the topological qubit and for supplementing the gate operations that cannot be performed by braiding of Majorana bound states. Furthermore, we extend our setup to a network of singlet-triplet and topological hybrid qubits that paves the way to scalable fault-tolerant quantum computing.MBS qubits are largely immune to decoherence effects arising from fluctuations in the electromagnetic fields or due to quasiparticle poisoning 46-52 .Eigenstates of the MBS qubit are degenerate, making energy-resolved readout of the MBS qubit impossible. arXiv:1902.10251v1 [cond-mat.mes-hall]

The germanium quantum information route

“…Perhaps the most exciting one is the interaction between topologically trivial and topological qubits. Quantum information transfer may occur between spin qubits based on individual holes and parity qubits based on MZM [247][248][249][250] . While scientifically highly interesting, such a transfer may also resolve key challenges in quantum information.…”

Manipulating Majorana zero modes in double quantum dots

“…The simplest case where Majorana manipulation is possible is in a double quantum dot (DQD). Tunneling Majorana modes in these basic structures have inspired theoretical studies [26][27][28][29] and experimental setups confirming the observations of Andreev molecules 30 . However, despite the fact that DQDs offer several possibilities for manipulation of MZMs, there is still no complete analysis of the possible transitions of these Majorana signatures between the QDs even in a simple model.…”

Hallmarks of Majorana mode leaking into a hybrid double quantum dot

“…Moreover, a rapid progress in materials science of superconducting hybrid nanostructures [4,5] stimulated vivid interest in constructing quantum bits out of the Andreev bound states [4,[6][7][8][9]. Further perspectives for the realization of topological superconducting qubits are related to nanostructures involving DQDs coupled to topological superconducting wires, hosting the Majorana zeroenergy modes (MZM) at their ends, the so-called Majorana wires (MW) [10][11][12][13][14][15]. Such platforms allow for the implementation of fault-tolerant quantum computing protocols, which are in the center of interest of quantum information research [16].…”