Topological light to connect quantum bits

Scientists propose a more robust way to connect quantum bits using topological light. Topological materials are more resistant to imperfections and can help build more robust chips for quantum computers.

In a simplified way, matter can be classified into three phases (solid, liquid and gas) according to how the atoms that make up the materials are stacked or move. This classification is based on local properties, that is, by looking at a small portion of the system it is possible to distinguish in which phase of matter it is. However, there are materials, known as topological materials, for which it is necessary to “look” at all the material to identify the phase. Recent advances allow these materials to be used to also shield the propagation of light therein.

The results of a study led by the Consejo Superior de Investigaciones Científicas (CSIC) in Spain indicate that it may be highly advantageous to use these topological photonic materials to build, among other things, quantum computer chips that are more resistant to imperfections. The study is a collaboration between researcher Alejandro González Tudela, from the CSIC’s Institute of Fundamental Physics (IFF), and scientists Iñaki García Elcano, Jaime Merino, and Jorge Bravo-Abad, from the Autonomous University of Madrid (UAM) in Spain. .

“In our work we have shown that, by placing quantum emitters on the surface of topological materials, these emitters can communicate through ‘topologically shielded’ photons. This means that its properties, such as conduction of electricity, are potentially better than those of conventional materials”, explains the IFF researcher.

Artist’s impression of topological light being used to connect quantum bits. (Image: Jorge Munnshe for NCYT of Amazings)

The researchers have used in this work techniques from quantum optics, the branch of physics that studies the interaction of light and matter on microscopic scales. “Since these quantum emitters can often encode quantum bits, this communication channel can be used to generate entangled states (a resource in quantum computing that relies on quantum bits rather than conventional bits) between emitters and to create ‘quantum gates’ that make it possible to process quantum information”, adds the CSIC scientist.

Although it is a theoretical finding, the objective is to be able to improve the robustness of current quantum technologies and their ability to be scaled up to larger scales. “These technologies can have a great impact because they allow information to be processed in a safer and faster way and even allow more precise measurements,” says González-.

The study is titled “Probing and harnessing photonic Fermi arc surface states using light-matter interactions”. And it has been published in the academic journal Science Advances. (Source: CSIC)