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Scientists can now identify the exact location of a single atom in a silicon crystal, a discovery that is key for greater accuracy in tomorrow’s silicon based quantum computers.

It’s now possible to track and see individual phosphorus atoms in a silicon crystal allowing confirmation of quantum computing capability, but which also has use in nano detection devices.

Continue reading “World-first pinpointing of atoms at work for quantum computers” »

For months, physicists have been quietly freaking out over tantalising evidence of a brand new particle lying outside the standard model of physics. First seen as a ’blip’ in Large Hadron Collider data, the hunt is now on to confirm its existence, which experts say would be “bigger than the [discovery of the] Higgs boson”.

And physicists have just made the case that another new particle could be waiting to be discovered, by showing that the existence of a mysterious new particle, which they’re calling ‘particle X’, could explain a significant conundrum in physics: where the heck all the missing lithium in the Universe went to.

If you haven’t heard about the case of the missing cosmic lithium, don’t worry, we weren’t across it either. But it turns out that scientists have calculated all the lithium that should have formed in the early Universe, and it’s about three times more lithium than we observe today.

Continue reading “Physicists hint at a mysterious new ‘particle X’ messing with our Universe” »

(Phys.org)—One of the most ambitious endeavors in quantum physics right now is to build a large-scale quantum network that could one day span the entire globe. In a new study, physicists have shown that describing quantum networks in a new way—as mathematical graphs—can help increase the distance that quantum information can be transmitted. Compared to classical networks, quantum networks have potential advantages such as better security and being faster under certain circumstances.

“A worldwide quantum network may appear quite similar to the internet—a huge number of devices connected in a way that allows the exchange of information between any of them,” coauthor Michael Epping, a physicist at the University of Waterloo in Canada, told Phys.org. “But the crucial difference is that the laws of quantum theory will be dominant for the description of that information. For example, the state of the fundamental information carrier can be a superposition of the basis states 0 and 1. By now, several advantages in comparison to classical information are known, such as prime number factorization and secret communication. However, the biggest benefit of quantum networks might well be discovered by future research in the rapidly developing field of quantum information theory.”

Quantum networks involve sending entangled particles across long distances, which is challenging because particle loss and decoherence tend to scale exponentially with the distance.

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Optica l quantum technologies are based on the interactions of atoms and photons at the single-particle level, and so require sources of single photons that are highly indistinguishable – that is, as identical as possible. Current single-photon sources using semiconductor quantum dots inserted into photonic structures produce photons that are ultrabright but have limited indistinguishability due to charge noise, which results in a fluctuating electric field. Conversely, parametric down conversion sources yield photons that while being highly indistinguishable have very low brightness. Recently, however, scientists at CNRS — Université Paris-Saclay, Marcoussis, France; Université Paris Diderot, Paris, France; University of Queensland, Brisbane, Australia; and Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France; have developed devices made of quantum dots in electrically-controlled cavities that provide large numbers of highly indistinguishable photons with strongly reduced charge noise that are 20 times brighter than any source of equal quality. The researchers state that by demonstrating efficient generation of a pure single photon with near-unity indistinguishability, their novel approach promises significant advances in optical quantum technology complexity and scalability.

Dr. Pascale Senellart and Phys.org discussed the paper, Near-optimal single-photon sources in the solid state, that she and her colleagues published in Nature Photonics, which reports the design and fabrication of the first optoelectronic devices made of quantum dots in electrically controlled cavities that provide bright source generating near-unity indistinguishability and pure single photons. “The ideal single photon source is a device that produces light pulses, each of them containing exactly one, and no more than one, photon. Moreover, all the photons should be identical in spatial shape, wavelength, polarization, and a spectrum that is the Fourier transform of its temporal profile,” Senellart tells Phys.org. “As a result, to obtain near optimal single photon sources in an optoelectronic device, we had to solve many scientific and technological challenges, leading to an achievement that is the result of more than seven years of research.”

Continue reading “The path to perfection: Quantum dots in electrically-controlled cavities yield bright, nearly identical photons” »

Riding the coattails of cold atomic physics, researchers have demonstrated the ability to steer cold molecules into desired quantum states.

Ultracold atoms have become a favorite tool in physics because they can be precisely placed in a quantum state using optical and magnetic fields. This quantum control has been crucial for understanding fundamental quantum-mechanical behavior and for creating metrological devices such as the atomic clocks that keep time for GPS systems. Current efforts are devoted to using these controllable systems to simulate, for example, superconductivity, but this and other future applications will likely require that the particles within the system interact with each other. Ultracold atoms do not interact very strongly, so an obvious alternative is to turn to molecules. As opposed to atoms, molecules can have an electric dipole, which lets them naturally interact strongly with each other through dipole forces. But molecules are not a straight substitute for atoms. They are much more complicated and thus significantly harder to cool and control than atoms.

“We are reaching the limits of how precisely we can test quantum theory on Earth,” says Daniel Oi at the University of Strathclyde. Researchers from the National University of Singapore (NUS) and the University of Strathclyde, UK, have become the first to test in orbit technology for satellite-based quantum network nodes. With a network that carries information in the quantum properties of single particles, you can create secure keys for secret messaging and potentially connect powerful quantum computers in the future. But scientists think you will need equipment in space to get global reach.

Another reliable article on the Quantum Internet work.

You can’t sign up for the quantum internet just yet, but researchers have reported a major experimental milestone towards building a global quantum network — and it’s happening in space.

With a network that carries information in the quantum properties of single particles, you can create secure keys for secret messaging and potentially connect powerful quantum computers in the future. But scientists think you will need equipment in space to get global reach.

Continue reading “Quantum satellite device tests technology for global quantum network” »

Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich and the Max Planck Institute for Quantum Optics (MPQ) have devised a new interferometer to probe the geometry of band structures.

The geometry and topology of electronic states in solids play a central role in a wide range of modern condensed-matter systems, including graphene and topological insulators. However, experimentally accessing this information has proven to be challenging, especially when the bands are not well isolated from one another. As reported by Tracy Li et al. in last week’s issue of Science (Science, May 27, 2016, DOI: 10.1126/science.aad5812), an international team of researchers led by Professor Immanuel Bloch and Dr. Ulrich Schneider at LMU Munich and the Max Planck Institute of Quantum Optics has devised a straightforward method with which to probe band geometry using ultracold atoms in an optical lattice. Their method, which combines the controlled transport of atoms through the energy bands with atom interferometry, is an important step in the endeavor to investigate geometric and topological phenomena in synthetic band structures.

A wide array of fundamental issues in condensed-matter physics, such as why some materials are insulators while others are metals, can be understood simply by examining the energies of the material’s constituent electrons. Indeed, band theory, which describes these electron energies, was one of the earliest triumphs of quantum mechanics, and has driven many of the technological advances of our time, from the computer chips in our laptops to the liquid-crystal displays on our smartphones. We now know, however, that traditional band theory is incomplete.

Researchers from the University of Bristol have used acoustics to make gauntlets that are able to levitate particles.

It seems that Earth is closer to Timelord technology than ever—particularly after a team of researchers from the University of Bristol in England unveiled their latest invention: the GauntLev.

The GauntLev functions similar to Doctor Who’s infamous sonic screwdriver. Well, almost. Timelord sonic screwdrivers can pick locks and disarm weapons, scan matter, and do a bunch of other cool stuff. Earthling sonic screwdrivers can levitate objects using sound waves.

Continue reading “Scientists Just Used Sound Waves to Make Gauntlets of Levitation” »