Anticrossings in Foerster Coupled Quantum Dots

Optical Schemes for Quantum Computation in Quantum Dot Molecules

We give three methods for entangling quantum states in quantum dots. We do this by showing how to tailor the resonant energy (Foerster-Dexter) transfer mechanisms and the biexciton binding energy in a quantum dot molecule. We calculate the magnitude of these two electrostatic interactions as a function of dot size, interdot separation, material composition, confinement potential and applied electric field by using an envelope function approximation in a two-cuboid dot molecule. In the first implementation, we show that it is desirable to suppress the Foerster coupling and to create entanglemen…

Selective spin coupling through a single exciton

We present a novel scheme for performing a conditional phase gate between two spin qubits in adjacent semiconductor quantum dots through delocalized single exciton states, formed through the inter-dot Foerster interaction. We consider two resonant quantum dots, each containing a single excess conduction band electron whose spin embodies the qubit. We demonstrate that both the two-qubit gate, and arbitrary single-qubit rotations, may be realized to a high fidelity with current semiconductor and laser technology.

Observation of Mollow Triplets with Tunable Interactions in Double Lambda Systems of Individual Hole Spins

Although individual spins in quantum dots have been studied extensively as qubits, their investigation under strong resonant driving in the scope of accessing Mollow physics is still an open question. Here, we have grown high quality positively charged quantum dots embedded in a planar microcavity that enable enhanced light-matter interactions. Under a strong magnetic field in the Voigt configuration, individual positively charged quantum dots provide a double-lambda level structure. Using a combination of above-band and resonant excitation, we observe the formation of Mollow triplets on all o…

Optical measurement and modeling of interactions between two hole or two electron spins in coupled InAs quantum dots

Two electron spins in quantum dots coupled through coherent tunneling are generally acknowledged to approximately obey Heisenberg isotropic exchange. This has not been established for two holes. Here we measure the spectra of two holes and of two electrons in two vertically stacked self-assembled InAs quantum dots using optical spectroscopy as a function of electric and magnetic fields. We find that the exchange is approximately isotropic for both systems, but that significant asymmetric contributions, arising from spin-orbit and Zeeman interactions combined with spatial asymmetries, are requi…

电子通过基于掺杂剂量子点的一维链的输运

Electron Transport Through a 1D Chain of Dopant-Based Quantum Dots

本研究利用扩展费米-哈伯德模型分析一维量子点链中的电荷输运，揭示能级排斥与等离激元行为，为硅掺杂半导体研究提供新见解。

低磁场下电子自旋量子比特在两个半导体量子点之间转移过程中的退相干

Decoherence of electron spin qubit during transfer between two semiconductor quantum dots at low magnetic fields

本文理论分析了低磁场下自旋量子比特在两个半导体量子点间绝热转移时的退相干机制，指出低隧穿耦合会放大各类误差，并提出硅基系统中实现高保真度转移所需的隧穿耦合条件。