Coherent coupling of a superconducting flux qubit to an electron spin ensemble in diamond

By Xiaobo Zhu, S. Saito, A. Kemp, K. Kakuyanagi, S. Karimoto, H. Nakano, William J. Munro, Y. Tokura, M. Everitt, Kae Nemoto and 3 more. Nature, 2011

371 citations recorded by the source corpus.

During the past decade, research into superconducting quantum bits (qubits) based on Josephson junctions has made rapid progress. Many foundational experiments have been performed, and superconducting qubits are now considered one of the most promising systems for quantum information processing. However, the experimentally reported coherence times are likely to be insufficient for future large-scale quantum computation. A natural solution to this problem is a dedicated engineered quantum memory based on atomic and molecular systems. The question of whether coherent quantum coupling is possible between such natural systems and a single macroscopic artificial atom has attracted considerable attention since the first demonstration of macroscopic quantum coherence in Josephson junction circuits. Here we report evidence of coherent strong coupling between a single macroscopic superconducting artificial atom (a flux qubit) and an ensemble of electron spins in the form of nitrogen–vacancy colour centres in diamond. Furthermore, we have observed coherent exchange of a single quantum of energy between a flux qubit and a macroscopic ensemble consisting of about 3 × 107 such colour centres. This provides a foundation for future quantum memories and hybrid devices coupling microwave and optical systems.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/1de1dbf0019b1b9728fd81929b685394196aeca3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Franco Nori
2. Sahel Ashhab
3. J. You
4. Göran Wendin
5. Z. Xiang
6. Can-Ming Hu
7. Yasunobu Nakamura
8. G. Bauer

In Materials Chemistry

1. Sahel Ashhab
2. Göran Wendin
3. Franco Nori

Citations in the corpus

• Hybrid quantum circuits: Superconducting circuits interacting with other quantum systems (2012, methodology): “Because these two types of electron spins naturally couple to each other in the experiment (Zhu et al., 2011), applying an external magnetic field to change the energy gap of NV centers or using a better sample could effectively improve the decay time of the NV center ensemble.”
• Quantum information processing with superconducting circuits: a review (2016, result): “Similar results were also achieved by directly coupling a flux qubit to an ensemble of NV centers without a resonator bus [235].”
• Cavity magnonics (2021, background): “Noninteracting spins form paramagnetic ensembles, such as nitrogen-vacancy (NV) centers in diamond (Kubo et al., 2011; Zhu et al., 2011), cold atomic clouds (Verdú et al., 2009), molecules (Eddins et al., 2014), and dilute magnetic ion-doped oxides (Longdell et al., 2005; Probst et al., 2013;…”