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arXiv · 2306.13209

Deterministic generation of arbitrary ultrasmall excitation of quantum systems by composite pulse sequences

Hayk L. Gevorgyan·Nikolay V. Vitanov
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Abstract

In some applications of quantum control, it is necessary to produce very weak excitation of a quantum system. Such an example is presented by the concept of single-photon generation in cold atomic ensembles or doped solids, e.g. by the DLCZ protocol, for which a single excitation is shared among thousands and millions atoms or ions. Another example is the possibility to create huge Dicke state of $N$ qubits sharing a single or a few excitations. Other examples are using tiny rotations to tune high-fidelity quantum gates or using these tiny rotations for testing high-fidelity quantum process tomography protocols. Ultrasmall excitation of a quantum transition can be generated by either a very weak or far-detuned driving field. However, these two approaches are sensitive to variations in the experimental parameters, e.g. the transition probability varies with the square of the pulse area. Here we propose a different method for generating a well-defined pre-selected very small transition probability -- of the order of $10^{-2}$ to $10^{-8}$ -- by using composite pulse sequences. The method features high fidelity and robustness to variations in the pulse area and the pulse duration.

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Hayk L. Gevorgyan, Nikolay V. Vitanov. 2023-06-22. Deterministic generation of arbitrary ultrasmall excitation of quantum systems by composite pulse sequences. https://arxiv.org/abs/2306.13209

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