Cost effective quantum moves a step closer

September 19, 2017

Canadian and US researchers have taken an important step towards enabling quantum networks to be cost-effective and truly secure from attack.

The experiments, by the team from the University of Calgary, the California Institute of Technology and the National Institute of Standards and Technology, Colorado, prove the viability of a measurement-device-independent quantum key distribution (QKD) system, based on readily available hardware.

QKD provides a method of provably secure communication. Many QKD systems, including commercial systems, have been developed during the last 30 years, and important elements such as secret key rates and maximum transmission have continuously improved.

The team's results, published today in the journal Quantum Science and Technology, shows how they employed cost-effective and commercially available hardware such as distributed feedback (DFB) lasers and field-programmable gate arrays (FPGA) electronics, which enable time-bin qubit preparation and time-tagging, and active feedback systems that allow for compensation of time-varying properties of photons after transmission through deployed fibre.

The first author Raju Valivarthi said: "Quantum hacking over the past decade has also shown, however, that the specifications of components and devices used in actual QKD systems never perfectly agree with the theoretical description used in security proofs, which can compromise the security of real QKD systems. For instance, so-called 'blinding attacks' exploit vulnerabilities of single photon detectors (SPDs) to open a side-channel, via which an eavesdropper can gain full information about the (assumed-to-be) secure key. Making practical QKD systems secure against all such attacks is a challenging task."

Senior author Dr. Qiang Zhou said: "Our MDI-QKD system includes four parts: qubit preparation module, Bell state measurement (BSM) module, control module, and time-tagging module, which allows key generation from qubits in randomly prepared states. It is worth to note that our control module in the demonstration is further improved to control the polarisation and arrival-time of photons travelling from Alice and Bob to Charlie, which ensures their indistinguishability at the moment of the BSM."

Group leader Professor Wolfgang Tittel said: "Our experimental demonstration paves the way for MDI-QKD-based star-type quantum networks with kbps secret key rates spanning geographical distances of more than 100km."

IOP Publishing

Related Photons Articles from Brightsurf:

An electrical trigger fires single, identical photons
Researchers at Berkeley Lab have found a way to generate single, identical photons on demand.

Single photons from a silicon chip
Quantum technology holds great promise: Quantum computers are expected to revolutionize database searches, AI systems, and computational simulations.

Physicists "trick" photons into behaving like electrons using a "synthetic" magnetic field
Scientists have discovered an elegant way of manipulating light using a ''synthetic'' Lorentz force -- which in nature is responsible for many fascinating phenomena including the Aurora Borealis.

Scientists use photons as threads to weave novel forms of matter
New research from the University of Southampton has successful discovered a way to bind two negatively charged electron-like particles which could create opportunities to form novel materials for use in new technological developments.

The nature of nuclear forces imprinted in photons
IFJ PAN scientists together with colleagues from the University of Milano (Italy) and other countries confirmed the need to include the three-nucleon interactions in the description of electromagnetic transitions in the 20O atomic nucleus.

Pushing photons
UC Santa Barbara researchers continue to push the boundaries of LED design a little further with a new method that could pave the way toward more efficient and versatile LED display and lighting technology.

Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.

An advance in molecular moviemaking shows how molecules respond to two photons of light
Some of the molecules' responses were surprising and others had been seen before with other techniques, but never in such detail or so directly, without relying on advance knowledge of what they should look like.

The imitation game: Scientists describe and emulate new quantum state of entangled photons
A research team from ITMO University, MIPT and Politecnico di Torino, has predicted a novel type of topological quantum state of two photons.

What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.

Read More: Photons News and Photons Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to