A pinboard by
Mikolaj Schmidt

Reseach associate (postdoctral researcher), Macquarie University


Designing new protocols for transfer of non-classical light beams between frequencies

Quantum computers are envisioned as distributed system, in which numerous nodes, capable of elementary quantum computations, collaborate extensively with each other to perform challenging computational tasks. To communicate, the nodes encode the results of their operations into photons, or quanta of light, and send them to other nodes. Over the last few years, tremendous effort from numerous research groups has brought us closer to realizing various architectures of the nodes, for example by using superconducting circuits or trapped ions. Our research, focused on the interface between these technologies, aims to increase the efficiency and the speed of the communication between non-identical nodes.

How do we plan to do this? Let us consider a simple analogy for a linear optical communication. Much like a simple message transferred by a line of people whispering into the neighbour's ear, photons sent into a linear optical waveguide can propagate over long distances, with little loss to the information content of the message. In this picture, if the frequencies of photons generated by the source node, and accepted by the destination node, differ, that the message has to be additionally translated between two languages (frequencies). The simplest approach would be to place two translators, or interfaces, at the ends of the communication channel. We propose an alternative approach, which relies on non-linear waveguides, which can themselves modify the frequencies of photons passing through the waveguide. Such systems would preserve the high quality of the communication channel, while eliminating the time-consuming process of translating the message. In our work we show how to realize such protocols in realistic physical systems.

With the research on different implementations of the quantum nodes progressing quickly, we hope that this work will provide the tools to interface these architectures, and later on, offer a reliable communication technology for the quantum internet.