Towards a buckyball spin future

December 20, 2020

Building the future of quantum technology requires highly controllable quantum units. Single atomic spins are forefront contenders for controllable quantum units. However, they are fragile and prone to lose information to their environment. To prevent this, we encapsulate the atomic spin inside a robust football-shaped molecule made of carbon, known as a buckyball.

Fig. 1: An atomic spin (blue sphere) encapsulated inside a buckyball cage. — **Fig. 1:** An atomic spin (blue sphere) encapsulated inside a buckyball cage.

© Max Planck Institute for Solid State Research

**Fig. 1:** An atomic spin (blue sphere) encapsulated inside a buckyball cage.

© Max Planck Institute for Solid State Research

Fig. 2: A nanoscale quantum sensor (pink arrow) inside a diamond pillar scans its environment (red hemisphere). It finds the fingerprint of a buckyball spin (shown in background spectrum). This fingerprint is encoded in the red light emitted by the quantum sensor. To extract this information, we must excite the sensor with a green laser. — **Fig. 2:** A nanoscale quantum sensor (pink arrow) inside a diamond pillar scans its environment (red hemisphere). It finds the fingerprint of a buckyball spin (shown in background spectrum). This fingerprint is encoded in the red light emitted by the quantum sensor. To extract this information, we must excite the sensor with a green laser.

© Max Planck Institute for Solid State Research

**Fig. 2:** A nanoscale quantum sensor (pink arrow) inside a diamond pillar scans its environment (red hemisphere). It finds the fingerprint of a buckyball spin (shown in background spectrum). This fingerprint is encoded in the red light emitted by the quantum sensor. To extract this information, we must excite the sensor with a green laser.

© Max Planck Institute for Solid State Research

Like an MRI scanner in a hospital, we look for the magnetic resonance fingerprint of our buckyball spin. However, since the signal from a buckyball spin is so weak, a traditional sensor cannot detect it. A nanoscale quantum sensor in diamond, however, can detect it. Once we find this magnetic resonance fingerprint, we control the behavior of this buckyball spin. As an example, we can make the spin point in a specific direction and rotate it at different speeds in endless circles.

Our work published in Nature Communications is the first experimental demonstration of an idea proposed over ten years ago. The idea involved controlling a single buckyball spin with a quantum sensor. The next milestone is to control an array of buckyball spins, all exchanging quantum information with each other. We are incredibly excited about the possibilities opened up by our technique towards building large-scale buckyball quantum machines in the near future.