Lifeboat Foundation

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.

It is one of the most astonishing results of physics: when a complex system is left alone, it will return to its initial state with almost perfect precision. Gas particles, for example, chaotically swirling around in a container, will return almost exactly to their starting positions after some time. This “Poincaré Recurrence Theorem” is the foundation of modern chaos theory. For decades, scientists have investigated how this theorem can be applied to the world of quantum physics. Now, researchers at TU Wien (Vienna) have successfully demonstrated a kind of “Poincaré recurrence” in a multi-particle quantum system. The results have been published in the journal Science.

An Old Question, Revisited

At the end of the 19th century, the French scientist Henri Poincaré studied systems which cannot be fully analysed with perfect precision — for example solar systems consisting of many planets and asteroids, or gas particles, which keep bumping into each other. His surprising result: every state which is physically possible will be occupied by the system at some point — at least to a very good degree of approximation. If we just wait long enough, at some point all planets will form a straight line, just by coincidence. The gas particles in a box will create interesting patterns, or go back to the state in which they were when the experiment started.

Among the different platforms for quantum information processing, individual electron spins in semiconductor quantum dots stand out for their long coherence times and potential for scalable fabrication. The past years have witnessed substantial progress in the capabilities of spin qubits. However, coupling between distant electron spins, which is required for quantum error correction, presents a challenge, and this goal remains the focus of intense research. Quantum teleportation is a canonical method to transmit qubit states, but it has not been implemented in quantum-dot spin qubits. Here, we present evidence for quantum teleportation of electron spin qubits in semiconductor quantum dots. Although we have not performed quantum state tomography to definitively assess the teleportation fidelity, our data are consistent with conditional teleportation of spin eigenstates, entanglement swapping, and gate teleportation. Such evidence for all-matter spin-state teleportation underscores the capabilities of exchange-coupled spin qubits for quantum-information transfer.