A team of researchers have successfully discovered that combining stable light paths with light particle interactions could make quantum computers more reliable and lead to new technological advancements.
The discovery arose after researchers from the Institute of Physics at the University of Rostock and Albert-Ludwigs-Universität Freiburg sought to study how light moves through special circuits called optical waveguides, using a concept called topology.
Discovering a way to topologically protect optical elements
Through their collaborative work, the researchers found a way to combine topologically robust propagation of light with the interference of photon pairs, after searching for such a connection for a long time.
Professor Alexander Szameit of the Institute of Physics at the University of Rostock said: “In topological systems, light only follows the global characteristics of the waveguide system. Local perturbations to the waveguides such as defects, vacancies, and disorder cannot divert its path. This result is truly a milestone.”
Commenting on the optical behaviours and mechanism at hand, the researchers said: “Pairs of photons that see each other perceive the waveguide structure as twisted. This causes them to link up, as if they were dancing along the twisted dance floor as a couple. Photons that pass through the waveguide separately only experience a conventional flat surface. So, we have a topological difference.”
The outcome is a potential design tool for topological protection of optical elements. Such usage could help to ensure proper operation of quantum computers, regardless of the finite manufacturing tolerances of the optical elements. This could help with the ever-increasing complexity of designs.
Building on previous scientific concepts
Like many incidents of scientific progression, the optical-focused work of the researchers arose from synthesis of seemingly unrelated concepts.
For example, the reciprocity of electricity and magnetism paved the way for Maxwell’s theory of light, which, up until now, is continually being refined and extended with ideas from quantum mechanics.
Similarly, the research group explored light evolution in optical waveguide circuits in the presence of topology using a mathematical concept that was initially developed to classify solid geometries according to their global properties.
Looking ahead to further research
Despite their amazements at how far it was possible to deform the waveguide system without any impact on quantum interference, the researchers believe there is more work to be done in the area and that the findings are just the beginning.
Professor Alexander Szameit concluded: “Our waveguide systems provide a rich pool of possibilities for constructing topological systems for light. The symbiosis with quantum light is just the beginning.”
