Enhancing the Coherence of a Spin Qubit by Operating it as a Feedback Loop That Controls its Nuclear Spin Bath - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




Enhancing the Coherence of a Spin Qubit by Operating it as a Feedback Loop That Controls its Nuclear Spin Bath - Condensed Matter > Mesoscale and Nanoscale Physics - Download this document for free, or read online. Document in PDF available to download.

Abstract: In many realizations of electron spin qubits the dominant source ofdecoherence is the fluctuating nuclear spin bath of the host material. Theslowness of this bath lends itself to a promising mitigation strategy where thenuclear spin bath is prepared in a narrowed state with suppressed fluctuations.Here, this approach is realized for a two-electron spin qubit in a GaAs doublequantum dot and a nearly ten-fold increase in the inhomogeneous dephasing time$T 2^*$ is demonstrated. Between subsequent measurements, the bath is preparedby using the qubit as a feedback loop that first measures its nuclearenvironment by coherent precession, and then polarizes it depending on thefinal state. This procedure results in a stable fixed point at a nonzeropolarization gradient between the two dots, which enables fast universal qubitcontrol.



Author: Hendrik Bluhm, Sandra Foletti, Diana Mahalu, Vladimir Umansky, Amir Yacoby

Source: https://arxiv.org/







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