Xavier Caillet | Searcharxiv

arXiv2006

Quantum Communication with Quantum Dot Spins

Single electron spins in quantum dots are attractive for quantum communication because of their expected long coherence times. We propose a method to create entanglement between two remote spins based on the coincident detection of two photons emitted by the dots. Local nodes of several qubits can be realized using the dipole-dipole interaction between trions in neighboring dots and spectral addressing, allowing the realization of quantum repeater protocols. We have performed a detailed feasibility study of our proposal based on tight-binding calculations of quantum dot properties.

quant-ph↗

arXiv2005

Precision of single-qubit gates based on Raman transitions

We analyze the achievable precision for single-qubit gates that are based on Raman transitions between two near-degenerate ground states via a virtually excited state. In particular, we study the errors due to non-perfect adiabaticity and due to spontaneous emission from the excited state. For the case of non-adabaticity, we calculate the error as a function of the dimensionless parameter $χ=Δτ$, where $Δ$ is the detuning of the Raman beams and $τ$ is the gate time. For the case of spontaneous emission, we give an analytical argument that the gate errors are approximately equal to $Λγ/Δ$, where $Λ$ is the rotation angle of the one-qubit gate and $γ$ is the spontaneous decay rate, and we show numerically that this estimate holds to good approximation.

quant-ph↗