HD quantum encryption gets a step closer to everyday use with world’s first urban trial

Researchers have sent a message secured with high-dimension quantum encryption through the air above a city for the first time in history, bringing practical use of the technology a step closer.

Using photons to encode information, quantum encryption is increasingly being explored as an ultra-secure method of sending information. However, previous real-world tests have only been focused around 2D encryption, where a single photon only encodes one bit: a single one or zero. As a single letter needs eight bits, this severely limits the amount of information that can be sent.

High-dimension quantum encryption, however, allows numerous bits to be stored in each photon, allowing greater quantities of data to be sent, and making it a far more practical option for real-world use.

But as the real world contains considerable ‘noise’ from turbulent air, failed electronics and even attempts by third parties to intercept the data, it is important to demonstrate HD quantum encryption works in an urban setting.

“Our work is the first to send messages in a secure manner using high-dimensional quantum encryption in realistic city conditions, including turbulence,” said research team lead, Ebrahim Karimi, from the University of Ottawa, Canada.

“The secure, free-space communication scheme we demonstrated could potentially link Earth with satellites, securely connect places where it is too expensive to install fiber, or be used for encrypted communication with a moving object, such as an airplane.”

The research, which is published today in the journal Optica, involved sending HD quantum-encrypted data over the city of Ottowa, Canada, over a distance of 0.3km.

The data, which was sent between two buildings at the university, was secured using 4D quantum encryption. This is named as such because each photon encodes two bits of information instead of one, resulting in four distinct possibilities: 01, 10, 00 or 11.

4D quantum encryption is important not only for its ability to send more data on the same number of photons, but because it is also more resistant to noise, making it more practical for real-world conditions.

“This higher noise threshold means that when 2D quantum encryption fails, you can try to implement 4D because it, in principle, is more secure and more noise resistant,” said Karimi.

The messages, which were sent between to rooftops, demonstrated an error rate of 11%, which is considered a key success as it is comfortably below the widely recognised threshold of 19% that is needed to keep a secure connection.

The researchers also found that 4D encryption enabled 1.6 times more information to be sent per photon than 2D encryption.

Image courtesy of SQO team, University of Ottawa

While the research is promising, there is undoubtedly still a long way to go before quantum encryption can be used for commercial applications.

Next the researchers plan to implement their 4D encryption into a network of three links, located 5.6km apart. In the long term, this will be linked into an established network within the city, to further test the use of the technology,

“Our long-term goal is to implement a quantum communication network with multiple links but using more than four dimensions while trying to get around the turbulence,” explained Alicia Sit, an undergraduate student in Karimi’s lab.

Soviet report detailing lunar rover Lunokhod-2 released for first time

Russian space agency Roskosmos has released an unprecedented scientific report into the lunar rover Lunokhod-2 for the first time, revealing previously unknown details about the rover and how it was controlled back on Earth.

The report, written entirely in Russian, was originally penned in 1973 following the Lunokhod-2 mission, which was embarked upon in January of the same year. It had remained accessible to only a handful of experts at the space agency prior to its release today, to mark the 45th anniversary of the mission.

Bearing the names of some 55 engineers and scientists, the report details the systems that were used to both remotely control the lunar rover from a base on Earth, and capture images and data about the Moon’s surface and Lunokhod-2’s place on it. This information, and in particularly the carefully documented issues and solutions that the report carries, went on to be used in many later unmanned missions to other parts of the solar system.

As a result, it provides a unique insight into this era of space exploration and the technical challenges that scientists faced, such as the low-frame television system that functioned as the ‘eyes’ of the Earth-based rover operators.

A NASA depiction of the Lunokhod mission. Above: an image of the rover, courtesy of NASA, overlaid onto a panorama of the Moon taken by Lunokhod-2, courtesy of Ruslan Kasmin.

One detail that main be of particular interest to space enthusiasts and experts is the operation of a unique system called Seismas, which was tested for the first time in the world during the mission.

Designed to determine the precise location of the rover at any given time, the system involved transmitting information over lasers from ground-based telescopes, which was received by a photodetector onboard the lunar rover. When the laser was detected, this triggered the emission of a radio signal back to the Earth, which provided the rover’s coordinates.

Other details, while technical, also give some insight into the culture of the mission, such as the careful work to eliminate issues in the long-range radio communication system. One issue, for example, was worked on with such thoroughness that it resulted in one of the devices using more resources than it was allocated, a problem that was outlined in the report.

The document also provides insight into on-Earth technological capabilities of the time. While it is mostly typed, certain mathematical symbols have had to be written in by hand, and the report also features a number of diagrams and graphs that have been painstakingly hand-drawn.

A hand-drawn graph from the report, showing temperature changes during one of the monitoring sessions during the mission

Lunokhod-2 was the second of two unmanned lunar rovers to be landed on the Moon by the Soviet Union within the Lunokhod programme, having been delivered via a soft landing by the unmanned Luna 21 spacecraft in January 1973.

In operation between January and June of that year, the robot covered a distance of 39km, meaning it still holds the lunar distance record to this day.

One of only four rovers to be deployed on the lunar surface, Lunokhod-2 was the last rover to visit the Moon until December 2013, when Chinese lunar rover Yutu made its maiden visit.

Robot takes first steps towards building artificial lifeforms

A robot equipped with sophisticated AI has successfully simulated the creation of artificial lifeforms, in a key first step towards the eventual goal of creating true artificial life.

The robot, which was developed by scientists at the University of Glasgow, was able to model the creation of artificial lifeforms using unstable oil-in-water droplets. These droplets effectively played the role of living cells, demonstrating the potential of future research to develop living cells based on building blocks that cannot be found in nature.

Significantly, the robot also successfully predicted their properties before they were created, even though this could not be achieved using conventional physical models.

The robot, which was designed by Glasgow University’s Regius Chair of Chemistry, Professor Lee Cronin, is driven by machine learning and the principles of evolution.

It has been developed to autonomously create oil-in-water droplets with a host of different chemical makeups and then use image recognition to assess their behaviour.

Using this information, the robot was able to engineer droplets to have different properties­. Those which were found to be desirable could then be recreated at any time, using a specific digital code.

“This work is exciting as it shows that we are able to use machine learning and a novel robotic platform to understand the system in ways that cannot be done using conventional laboratory methods, including the discovery of ‘swarm’ like group behaviour of the droplets, akin to flocking birds,” said Cronin.

“Achieving lifelike behaviours such as this are important in our mission to make new lifeforms, and these droplets may be considered ‘protocells’ – simplified models of living cells.”

One of the oil droplets created by the robot

The research, which is published today in the journal PNAS, is one of several research projects being undertaken by Cronin and his team within the field of artificial lifeforms.

While the overarching goal is moving towards the creation of lifeforms using new and unprecedented building blocks, the research may also have more immediate potential applications.

The team believes that their work could also have applications in several practical areas, including the development of new methods for drug delivery or even innovative materials with functional properties.