Physicists at the Johannes Gutenberg University Mainz have developed a quantum interface which connects light particles and atoms. The interface is based on an ultra-thin glass fiber and is suitable for the transmission of quantum information.
This is an essential prerequisite for quantum communication which shall be used for secure data transmission via quantum cryptography. "Our quantum interface might also prove useful for the realization of a quantum computer," adds Professor Dr Arno Rauschenbeutel from the Institute of Physics at Mainz University.
Today, telephone and internet primarily rely on the optical transmission of data using glass fiber cables. In that sense, glass fiber networks can be considered as the backbone of the modern communication society. The light that travels through them is not a continuous flow of energy. It rather consists, as was discovered by Albert Einstein, of indivisible energy quanta, or photons. Each photon can then transmit one bit of information, corresponding to a zero or one. In addition to being very efficient, this also opens the route towards entirely new ways of communication because, being quantum objects, photons can exist simultaneously in both states, zero and one.
As an example, this property is what makes quantum cryptography possible and thereby enables absolute protection against eavesdropping. In order to fully exploit the potential of quantum communication, however, one additionally needs the possibility to store the quantum information that is encoded on each photon. Photons themselves are not well suited for this purpose because one cannot hold them at a given position. Therefore, it would be much more advantageous to transfer the quantum information to atoms. For this purpose one thus requires a quantum interface between photons and atoms which should ideally be easily integrated into glass fiber networks.
A group of physicists led by Professor Arno Rauschenbeutel at the Johannes Gutenberg University Mainz, Germany, has now realized such a glass fiber-based quantum interface. As reported by the research team in the current issue of the scientific journal Physical Review Letters, the central part of the work in Mainz is a glass fiber which has been heated and stretched until it measures only one hundredth of the diameter of a human hair. Remarkably, this nanofiber is thinner than the wavelength of the light it guides. As a consequence, the light is no longer restricted to the inside of the nanofiber but laterally protrudes into the space surrounding the fiber. Using this so-called evanescent field, the scientists trapped cesium atoms after they have been cooled to a few millionth of a degree above absolute zero by irradiation with suitably chosen laser light. When trapped, the atoms are arranged in a regular pattern and are levitated 200 nm above the surface of the nanofiber. This distance might seem very small but it indeed is big enough to protect the atoms from the spurious influences of the fiber surface. At the same time, the atoms reside in the evanescent field and thus interact with the photons propagating through the nanofiber.
As was demonstrated by the Mainz researchers, this process is so efficient that only a couple of thousand atoms should suffice for a close to lossless transfer of quantum information between photons and atoms. Further possible applications of the Mainz quantum interface include the connection of different quantum systems. As an example, the trapped atoms could be brought into close vicinity of a superconducting quantum circuit in order to combine the advantageous properties of both systems. This would then be an important step towards the realization of a quantum computer.
Petra Giegerich | idw
NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center
Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Physics and Astronomy
30.03.2017 | Studies and Analyses
30.03.2017 | Life Sciences