‘Spooky action at a distance’ demonstrated in single-particle quantum experiment for first time

A team of scientists have for the first time successfully demonstrated the non-local collapse of a particle’s wave function in an experiment using a single particle.

Using homodyne detectors to measure the particle, and quantum tomography to map the effect of those measurements, the scientists, from Griffith University and the University of Tokyo, were able to verify single-particle quantum entanglement an unusual form of entanglement that could prove invaluable for quantum computing and communications.

While quantum entanglement usually refers to two particles that are bound by opposing spins, the directions of which will only be set when they are observed, single particles can also be entangled, meaning their wave function – ie the equation that defines their likely location and behaviour – can cover any distance.

In other words, a single entangled particle can only be in one place at a given time, but it can be located over a very large distance. When the particle is measured, the wave function will instantly collapse to a set location.

Professor Howard Wiseman at the Centre for Quantum Dynamics. Image courtesy of Griffith University.

Professor Howard Wiseman at the Centre for Quantum Dynamics. Image courtesy of Griffith University.

This was demonstrated by the scientists, who split a single photon between their labs in Japan and Australia, but was previously regarded as an unlikely phenomenon by Albert Einstein.

Almost 90 years ago, he used single-particle entanglement as evidence that quantum mechanics was incorrect, deriding non-local wave function collapse as “spooky action at a distance”.

“Einstein never accepted orthodox quantum mechanics and the original basis of his contention was this single-particle argument,” explained Professor Howard Wiseman, director of Griffith University’s Centre for Quantum Dynamics.

“This is why it is important to demonstrate non-local wave function collapse with a single particle.”

While taking issue with quantum mechanics, Einstein proposed an alternative hypothesis for the particle’s behaviour.

“Einstein’s view was that the detection of the particle only ever at one point could be much better explained by the hypothesis that the particle is only ever at one point, without invoking the instantaneous collapse of the wave function to nothing at all other points.”

Although this alternative theory seems more acceptable to the human brain, Wiseman and his colleagues have shown it to be incorrect.

“Rather than simply detecting the presence or absence of the particle, we used homodyne measurements enabling one party to make different measurements and the other, using quantum tomography, to test the effect of those choices,” he explained.

“Through these different measurements, you see the wave function collapse in different ways, thus proving its existence and showing that Einstein was wrong.”

The research was published today in Nature Communications.


Journal reference: Fuwa M, Takeda S, Zwierz M, Wiseman HM, Furusawa A. Experimental proof of nonlocal wavefunction collapse for a single particle using homodyne measurements. Nature Communications 06 March 2015. doi:10.1038/ncomms7665.


 

China planning to end sales of fossil-fuel-powered vehicles

Xin Guobin, China's vice minister of industry and information technology, has said the government is working with regulators to put in place a timetable to end the production and sale of cars powered by fossil fuels. It's hoped the move will accelerate the expansion of the electric car market.

Source: Bloomberg

Limited Tesla Autopilot was "partly to blame" for crash

The US National Transportation Safety Board (NTSB) has found that Tesla's Autopilot system was partly to blame for a fatal accident in which a Model S collided with a lorry. The safety board concluded that Tesla allowed the driver to use the system outside of the environment for which it was designed,

Source: BBC

Chelsea Manning warns about the risks of AI

During a conversation at Noisebridge hackerspace, Chelsea Manning commented on some of the inherent risks of AI. "We’re now using huge datasets with all kinds of personal data, that we don’t even know what information we’re putting out there and what it’s getting collected for," Manning said.

Source: Ars Technica

US government bans Kaspersky software from its agencies

The Department of Homeland security has ordered government agencies to stop using software products made by Kaspersky Lab because of possible ties between Kaspersky officials and Russian intelligence. The process of discontinuing Kaspersky products is expected to begin within 90 days.

Source: Ars Technica

Hyperloop One selects ten possible routes for the first hyperloop

Hyperloop One has announced that it has selected ten proposed routes for the first hyperloop. The company also announced that it would “commit meaningful business and engineering resources and work closely with each of the winning teams/routes to determine their commercial viability”.

Source: Inverse

Artificial 'skin' gives robotic hand a sense of touch

A team of researchers from the University of Houston has reported a breakthrough in stretchable electronics that can serve as an artificial skin, allowing a robotic hand to sense the difference between hot and cold, while also offering advantages for a wide range of biomedical devices.

Source: Science Daily

The plan to make every surface inside the car of the future smart

Yanfeng Automotive Interiors (YFAI) has revealed a vision for the future of cars where every surface inside the vehicle can become a smart surface.

Launched at the International Auto Show, YFAI’s activeSkin concept will turn the largely decorative surfaces inside cars, including the door trim, floor console and instrument panel, into smart interior surfaces, which YFAI says will be “fully interactive” and could be ready by 2022.

“The future generation of surfaces will be smarter than ever. Just by passing your hand over a upholstered surface of the car will appear an interactive surface or dynamic decorative ambient light. Surfaces interact with us, “says Han Hendriks , YFAI’s chief technology officer.

“This technology is impressive.”

Images courtesy of YFAI

YFAI says its customisable 3D glass surfaces could benefit drivers by replacing some of the current operating elements in traditional cars.

However, If no information is called up by the driver, integrated screens and operating surfaces would remain invisible as purely decorative glass surfaces, so drivers would not be distracted by unnecessary information popping up.

“We offer on-demand functionality, so it will only be visible when you need it. In this way we will be able to customise features on interior surfaces,” said Hendriks. “With activeSkin we can achieve a 3D effect that gives a feeling of amazing depth.”

This isn’t the first time YFAI has tried to predict what cars of the future will be like.

The company’s XiM17 concept car was designed with autonomous driving in mind and helped answer the question, “What will people do in their vehicle, if they no longer have to drive?”

YFAI’s XiM17 allows passengers to switch between a number of different modes to allow passengers a number of different ways of engaging.

For example, in family mode all four seats in the car are positioned facing each other, whereas in meeting mode the rear seats are folded away. so that the driver and passenger seats face each other. and a floor console rises to form a desk.