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Graphene’s unique 2-D structure means that electrons travel through it differently than in most other materials. One consequence of this unique transport is that applying a voltage doesn’t stop the electrons like it does in most other materials. This is a problem, because to make useful applications out of graphene and its unique electrons, such as quantum computers, it is necessary to be able to stop and control graphene electrons.

An interdisciplinary team of scientists from the Universidad Autonoma de Madrid (Spain), Université Grenoble Alpes (France), International Iberian Nanotechnology Laboratory (Portugal) and Aalto University has solved this long-standing problem. The team included experimental researchers Eva Cortés del Río, Pierre Mallet, Héctor González‐Herrero, José María Gómez‐Rodríguez, Jean‐Yves Veuillen and Iván Brihuega and theorists including Joaquín Fernández-Rossier and Jose Lado, assistant professor in the department of Applied Physics at Aalto.

The experimental team used atomic bricks to build walls capable of stopping the graphene electrons. This was achieved by creating atomic walls that confined the electrons, leading to structures whose spectrum was then compared with theoretical predictions, demonstrating that electrons were confined. In particular, it was obtained that the engineered structures gave rise to nearly perfect confinement of electrons, as demonstrated from the emergence of sharp quantum well resonances with a remarkably long lifetime.

Updated mathematical techniques that can distinguish between two types of ‘non-Gaussian curve’ could make it easier for researchers to study the nature of quantum entanglement.

Quantum entanglement is perhaps one of the most intriguing phenomena known to physics. It describes how the fates of multiple particles can become entwined, even when separated by vast distances. Importantly, the probability distributions needed to define the quantum states of these particles deviate from the bell-shaped, or ‘Gaussian’ curves which underly many natural processes. Non-Gaussian curves don’t apply to quantum systems alone, however. They can also be composed of mixtures of regular Gaussian curves, producing difficulties for physicists studying quantum entanglement. In new research published in EPJ D, Shao-Hua Xiang and colleagues at Huaihua University in China propose a solution to this problem. They suggest an updated set of equations that allows physicists to easily check whether or not a non-Gaussian state is genuinely quantum.

As physicists make more discoveries about the nature of quantum entanglement, they are rapidly making progress towards advanced applications in the fields of quantum communication and computation. The approach taken in this study could prove to speed up the pace of these advances. Xiang and colleagues acknowledge that while all previous efforts to distinguish between both types of non-Gaussian curve have had some success, their choices of Gaussian curves as a starting point have so far meant that no one approach has yet proven to be completely effective. Based on the argument that there can’t be any truly reliable Gaussian reference for any genuinely quantum non-Gaussian state, the researchers present a new theoretical framework.

In the strange field of quantum physics, quantum entanglement – what Einstein called “spooky action at a distance” – stands out as one of the most intriguing phenomena. And now scientists just managed to successfully demonstrate it again, this time onboard a CubeSat satellite orbiting Earth.

Quantum entanglement is where two particles become inextricably linked across a distance, so that one serves as an indicator of the other in a certain aspect. That unbreakable link might one day form the basis of a super-fast, super-secure quantum internet.

While a quantum internet is still some way off, if we want to make it work, it’s going to require something other than optical fibres.

By making use of the ‘spooky’ laws behind quantum entanglement, physicists think have found a way to make information leap between a pair of electrons separated by distance.

Teleporting fundamental states between photons – massless particles of light – is quickly becoming old news, a trick we are still learning to exploit in computing and encrypted communications technology.

But what the latest research has achieved is quantum teleportation between particles of matter – electrons –something that could help connect quantum computing with the more traditional electronic kind.

Quantum computers have the potential to revolutionise the way we solve hard computing problems, from creating advanced artificial intelligence to simulating chemical reactions in order to create the next generation of materials or drugs. But actually building such machines is very difficult because they involve exotic components and have to be kept in highly controlled environments. And the ones we have so far can’t outperform traditional machines as yet.

But with a team of researchers from the UK and France, we have demonstrated that it may well be possible to build a quantum computer from conventional silicon-based electronic components. This could pave the way for large-scale manufacturing of quantum computers much sooner than might otherwise be possible.

Continue reading “Quantum computers could arrive sooner if we build them with traditional silicon technology” »

Pulses of light from infrared lasers can speed up computer operations by a factor of 1 million, and may have opened the door to room-temperature quantum computing.

A new study makes quantum encryption much more practical, and brings us closer to the dream of a latency-free internet.

Certain galaxy patterns might encode whether the Universe’s primordial density fluctuations were quantum or classical in nature.

NDSU researchers recently developed a new method of creating quantum dots made of silicon. Quantum dots, or nanocrystals, are tiny nanometer-scale pieces of semiconductor that emit light when their electrons are exposed to UV light. The most common application of quantum dots is in QLED displays. Through their use, digital displays have become brighter and much thinner, resulting in improvements to television and, potentially, cell-phone technology.

Because silicon is abundant and nontoxic, silicon quantum dots have unique technological appeal. Silicon quantum dots are currently being used for applications such as windows that remain transparent while serving as active photovoltaic collectors of energy, and they hold promise in medicine where quantum dots are coated with organic molecules to create nontoxic fluorescent biomarkers.

While traditional methods for creating silicon quantum dots require dangerous materials such as silicon tetrahydride (silane) gas or hydrofluoric acid, the NDSU team’s research uses a liquid form of silicon to make the tiny particles at room temperature using relatively benign components.