Related papers: Entanglement-symmetry control in a quantum-dot Coo…
We propose a novel approach for efficient generation of entangled photons, based on Cooper-pair luminescence in semiconductors, which does not require isolated emitters such as single atoms or quantum dots. We show that in bulk materials,…
In hybrid quantum systems a controllable coupling can be obtained by mediating the interactions with dynamically introduced photons. We propose a hybrid quantum architecture consisting of two nitrogen vacancy center ensembles coupled to a…
We theoretically study tunneling of Cooper pairs from an s-wave superconductor into two semiconductor quantum wires with strong spin-orbit interaction under magnetic field, which approximate helical Luttinger liquids. The entanglement of…
Cooper pair splitting (CPS) is a process in which the electrons of naturally occurring spin-singlet pairs in a superconductor are spatially separated using two quantum dots. Here we investigate the evolution of the conductance correlations…
Spin qubits defined in carbon nanotube quantum dots are of considerable interest for encoding and manipulating quantum information because of the long electron spin coherence times expected. However, before carbon nanotubes can find…
Coupled electron spins in semiconductor double quantum dots hold promise as the basis for solid-state qubits. To date, most experiments have used III-V materials, in which coherence is limited by hyperfine interactions. Ge/Si…
A spin-orbit qubit is a hybrid qubit that contains both orbital and spin degrees of freedom of an electron in a quantum dot. Here we study the exchange coupling between two spin-orbit qubits in a nanowire double quantum dot (DQD) with…
We study controllable exchange coupling between two singlet-triplet qubits. We start from the original second quantized Hamiltonian of a quadruple quantum dot system and obtain the effective spin-spin interaction between the two qubits…
An unconventional superconductor is distinguished with two types of gap functions: unitary and non-unitary. This core subject has been concentrated on purely spin-triplet or singlet-triplet mixed superconductors. However, the generalization…
We theoretically study tunneling of Cooper pairs from a superconductor spanning a two-dimensional topological insulator strip into its helical edge states. The coherent low-energy electron-pair tunneling sets off positive current cross…
Whereas there exists considerable evidence for the conversion of singlet Cooper pairs into triplet Cooper pairs in the presence of inhomogeneous magnetic fields, recent theoretical proposals have suggested an alternative way to exert…
We investigate quantum repeater protocols based upon atomic qubit-entanglement distribution through optical coherent-state communication. Various measurement schemes for an optical mode entangled with two spatially separated atomic qubits…
We model a superconducting p-n junction in which the n- and the p-sides are contacted through two optical quantum dots (QDs), each embedded into a photonic nanocavity. Whenever a Cooper pair is transferred from the n-side to the p-side, two…
Spin properties of two interacting electrons in a quantum dot (QD) embedded in a nanowire with controlled aspect ratio and longitudinal magnetic fields are investigated by using a configuration interaction (CI) method and exact…
Quantum engineering requires controllable artificial systems with quantum coherence exceeding the device size and operation time. This can be achieved with geometrically confined low-dimensional electronic structures embedded within…
Manipulation of the spin-states of a quantum dot by purely electrical means is a highly desirable property of fundamental importance for the development of spintronic devices such as spin-filters, spin-transistors and single-spin memory as…
Solid state quantum bits are a promising candidate for the realization of a scalable quantum computer, however, they are usually strongly limited by decoherence. We consider a double quantum dot charge qubit, whose basis states are defined…
Split Cooper pair is a natural source for entangled electrons which is a basic ingredient for quantum information in solid state. We report an experiment on a superconductor-graphene double quantum dot (QD) system, in which we observe…
We consider a new kind of superconducting proximity effect created by the tunneling of "spin split" Cooper pairs between two conventional superconductors connected by a normal conductor containing a quantum dot. The difference compared to…
Few-electron states in carbon-nanotube quantum dots are studied by means of the configuration-interaction method. The peculiar non-interacting feature of the tunneling spectrum for two electrons, recently measured by Kuemmeth et al. [Nature…