Little more than a system of two energy levels could be used to control a single particle of light
Modern electronics is built upon the control of electric charges through an electric field. Computing based on photons rather than electrons, on the other hand, promises significantly faster computation and information processing. An international team of researchers has now developed a theoretical system that would allow single photons to be controlled reliably. “The system we propose can be used as a quantum switch to control the transport of single photons,” says team member Franco Nori from the Advanced Science Institute, Wako, and The University of Michigan, USA.
In contrast to electrons, exercising control over photons is rather difficult to achieve, because light travels at high speeds and hardly interacts with matter. This has hampered the realization of schemes such as all-optical computing. The use of resonators, however, offers a solution to better control the way light propagates. Resonators are small cavities, bound by mirrors at both ends that bounce light back and only occasionally let light out.
As reported in the journal Physical Review Letters (1), the researchers studied a chain of resonators coupled together so that photons propagate along this line. A system with two energy levels was placed in the center of this coupled-resonator waveguide. To facilitate the interaction between light and the two-level system the separation of the two energy levels is close to the photon energy.
When there is a perfect match between the photon energy and the separation of energy levels, the two-level system interacts with the photon; physics then dictates that the photon will be reflected. However, when the energies of the photon and the two-level system do not match, the photon will be transmitted towards the other end of the waveguide.
“Such a two-level system with adjustable energy levels could be used as a switch that controls the propagation of a single photon in the same way a transistor controls the transport of electrons,“ says team member C. P. Sun from The Chinese Academy of Sciences, Beijing.
To realize this two-level system the researchers suggest using so-called superconducting qubits, used in connection with superconducting resonators, which have been demonstrated already, as the waveguides. The separation of the qubit energy levels can be easily controlled and could even be done with another single photon. The researchers have demonstrated theoretically that, with the right choice of system parameters, switching can be easily achieved. “We believe such a system is well within reach of current technology,” says RIKEN’s Lan Zhou.
1. Zhou, L., Gong, Z. R., Liu, Y.-X., Sun, C. P. & Nori, F. Controllable Scattering of a Single Photon inside a One-Dimensional Resonator Waveguide. Physical Review Letters 101, 100501 (2008).
The corresponding author for this highlight is based at the RIKEN Digital Materials Team
Fingerprints of quantum entanglement
16.02.2018 | University of Vienna
Simple in the Cloud: The digitalization of brownfield systems made easy
07.02.2018 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy