Precision of single-qubit gates based on Raman transitions

Abstract

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 $\chi =\Delta \tau$, where $\Delta$ is the detuning of the Raman beams and $\tau$ is the gate time. For the case of spontaneous emission, we give an analytical argument that the gate errors are approximately equal to $\Lambda \gamma /\Delta$, where $\Lambda$ is the rotation angle of the one-qubit gate and $\gamma$ is the spontaneous decay rate, and we show numerically that this estimate holds to good approximation.

8 pages, 10 figures

References in corpus (4)

• Arbitrary rotation and entanglement of flux SQUID qubits
• Phonon-induced decoherence for a quantum dot spin qubit operated by Raman passage
• Selective spin coupling through a single exciton
• Ultrafast initialization and QND-readout of a spin qubit via control of nanodot-vacuum coupling

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