Look around you. Probably a lot of the things that you can see have something to do with quantum mechanics. Even the light from the screen that you are using right now has a very ‘quantum’ description. However, not all of these things are readily usable as a qubit, the basic unit of quantum information processing. Only in particular environments, we can use the laws of quantum mechanics to our advantage.
These unique environments, so-called “quantum materials”, are essential in the road to quantum information processing applications. In this video, Giordano Scapucci (QuTech) introduces the research field that looks into optimizing these materials, discusses their parameters, and cites several real-life examples.
- Introductory solid state physics if you want to recognize all the examples in the video
A quantum computer should have some necessary properties to be called as such. These properties are the DiVincenzo criteria:
- The system must be scalable with well-defined qubits;
- The computer must have the ability to initialize the state of qubits;
- Qubits must have long decoherence times;
- The computer must be able to perform a universal set of quantum gates on the qubits;
- It should be possible to measure the qubits.
We have to keep these criteria in mind when we choose the material for our qubits. For example, having homogeneous materials makes it possible to scale the system easily.
Which property should the material have to ensure long decoherence times?
A. Use materials with low density where qubits can easily be accessed for error correction.
B. Use materials with high density to reduce the interaction of qubits with neighboring qubits.
C. Use materials that can be cooled down quickly.
D. Avoid materials with a complex structure, as it is more likely to interact with the qubits.
The research field of Quantum Materials is vast. For each type of qubit, there is a lot of ‘Quantum Material research’ that can be read. Below you can find some of the more general sources to extend your reading on the subject.
If you have watched the video and still find the understanding to be a bit difficult, check out this Newsletter on Quantum Materials. Here postdoctoral researcher at Johns Hopkins University Elizabeth Pogue writes about Quantum Materials for a broad target audience. https://www.energyfrontier.us/content/what-are-quantum-materials
Experts can take a look at this Nature paper on the ‘rise of quantum materials’. https://www.nature.com/articles/nphys3668
For a more extensive expert insight in the field of Quantum Materials, take a look at the Nature collection of papers on the subject. This collection explores the physics of quantum materials, their synthesis and design, the control over their properties, and the functionality that emerges from these properties. https://www.nature.com/collections/ydsxkfvwws/