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Sujet de stage / Master 2 Internship

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Vers le calcul quantique à base de spins nucléaires

Contact: BERTET Patrice, , patrice.bertet@cea.fr, +33 1 69 08 55 29
Summary:
The internship is part of a research project that aims at using nuclear spins in solids (which can have ultra-long coherence times, up to few hours) as quantum bits for quantum computing. The spin state will be measured by coupling them to superconducting circuits.
Possibility of continuation in PhD: Oui
Deadline for application:27/04/2018

Full description:
Nuclear spins in solids are quantum systems that are well protected from their environment and can therefore have exceptionally long coherence times (up to several hours). It is thus tempting to use them as carrier of quantum information, in a quantum processor. It remains however utterly difficult to readout the quantum state of a single nuclear spin, and even more so to couple two nuclear spins that are distant from each other, which is needed for quantum logic operations.
Our group is leading a long-term research project (in collaboration with an industrial and with the support of an ERC grant) that aims at using superconducting circuits to measure and interface nuclear spin qubits. In a first step we wish to demonstrate quantum state manipulation and readout of a single nuclear spin, using its hyperfine coupling to an electron spin, itself coupled to a superconducting resonator. This strategy applies to a large variety of physical systems; we work in particular with NV centers in diamond, donors in silicon, and Erbium ions in orthosilicate crystals. In order to reach our goal, we need to be able to detect a single electronic spin, in a measurement time smaller than one second.
The internship relies on recent results obtained in our team, demonstrating the detection of a very small number of electronic spins with a sensitivity 5 orders of magnitude higher than the previous state-of-the-art [1,2,3]. Our spectrometer has demonstrated a sensitivity of 65 spins / \sqrt{Hz} by measuring donors in silicon; we thus simply need to win another two orders of magnitude. The goal of the internship will be to do so by turning to a different system : Erbium ions in a YSO matrix. Indeed, these ions have a magnetic moment that is 7 times higher than donors in silicon, which would automatically bring the spectrometer sensitivity below the 1spin/\sqrt{Hz} value, and would bring the first experimental demonstration of single spin detection with microwave signals.
Technics/methods used during the internship:
- Cleanroom techniques - Ultra-low-noise microwave measurements - Cryogenic températures (mK)

Laboratory
Tutor of the internship

 

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