Quantum comms

An international team of scientists have made a major breakthrough in the quest to create a viable quantum communication network. The discovery moves researchers a step closer towards an ultra-secure future network of interconnected super-fast quantum computers. 

Dr Mehul Malik of Heriot-Watt’s Institute of Photonic and Quantum Sciences (IPaQS) is one of an 11-strong group of physicists who have, for the first time, carried out a series of experiments where the quantum property known as entanglement was successfully transferred under real-world conditions by utilising the enigmatic properties of quantum physics.  

The experiments demonstrated the ability of quanta to overcome its biggest hurdle, the natural environment. Known as ‘noise’, this obstacle has, until now, stood in the way of entanglement-based quantum communication.

This is a very exciting development for us and is particularly relevant in today’s day and age, where information security plays an ever-increasing role in our daily lives.

Dr Mehul Malik

Quantum communication, and an eventual quantum internet, which is believed could become a reality in the next two decades, promise to bring an end to hacking due to the complex quantum states where information is encoded onto a single light particle, or photon. These photons can then be shared over arbitrary distances and decoded by a receiving quantum computer. What makes this possible is an important quantum phenomena known as ‘entanglement’ where there is a strong correlation between particles over great distances. 

When these quantum states are disturbed, such as an attempted hack, the entanglement is lost, meaning it is impossible to copy the information each holds preventing data from being stolen.

The concept has already been proven under test conditions with information shared on ‘entangled’ light particles however it was found to be unreliable when exposed to noise where even particles of sunlight would interrupt and prevent the photons from being received correctly. 

The group has, however, successfully overcome this problem by using high-dimensional quantum states, which Dr Malik explains, is a game-changer for quantum communications.

Dr Malik, continues: “Even a small amount of noise, such as stray light entering a detector, can lead to the destruction of entanglement.

“What’s particularly exciting about our findings is that for the first time, quantum entanglement is shown to survive in daylight conditions. This will allow the strongest form of quantum-secure communication to be performed in a real-world environment, making it a huge leap forward towards the creation of a quantum internet.”

The two-year project has been led by researchers at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences (OeAW), and has succeeded in making quantum entanglement more robust, as reported in the online journal Physical Review X.

Not only has the entanglement itself become more secure, but it can also be maintained over greater distances.

“This is a very exciting development for us and is particularly relevant in today’s day and age, where information security plays an ever-increasing role in our daily lives,” explained Dr Malik.

The global project team will now use their findings to help work towards the advancement of quantum communications and ultimately a secure internet.

OeAW physicist Sebastian Ecker, said: “Quantum entanglement is the backbone of quantum communication. A secure internet can only exist if the entanglement is transmitted largely undisturbed. With our experiment we were able to show how the entanglement can be made more resilient. This is another important step towards the quantum internet of the future.”

Research into quantum technology for computing and communications is in its infancy however businesses around the world, including Google, are investing billions of dollars into this fledgling technology. 

The journal report has been published in Physical Review X and can be read here

Craig McManamon

Communications Officer

T: 0131 451 8099

E: c.mcmanamon@hw.ac.uk

Image: courtesy of Harald Ritsch/IQOQI Vienna