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Category: quantum physics – Page 599

:oooo circa 2009.

The portrait of Peter Higgs is on display at the University of Edinburgh’s School of Informatics. Photograph: Ken Currie.

It seems that Peter Higgs, despite his known aversion to publicity is turning up everywhere. Of course the potential discovery of the particle in the next few years by either/both of the Large Hadron Collider at CERN and the Tevatron at Fermilab is bringing a lot more attention to him, and a little to the other theorists, such as Guralnik, Hagen, Kibble, Brout, and Englert, who also developed the ideas behind a mass-giving spontaneously symmetry broken quantum field and its manifestation as a particle, now known as the Higgs boson. (Yep, that sounds scary because it gets technical.)

But Higgs the man seems to turn up in all kinds of places and lots of people have stories about where and how they met the man. I ran into him in at a function in a museum in the Hunterian Museum at the University of Glasgow over a decade ago, while Lauren, one of the symmetry interns, used to make him his sandwich in a cafe most days when she spent time in Glasgow. (Tell us your story of meeting Higgs in the comments below.)

Continue reading “Higgs turning up everywhere, this time in paint” | >

Ions trapped nanoscale optical cavities could be used to distribute entangled quantum particles over large distances. That is the conclusion of Jonathan Kindem and colleagues at Caltech in the US, who showed that a trapped ion of ytterbium can remain entangled with a photon for long periods of time. Furthermore, the team showed that the ion’s quantum state can be read out when manipulated by laser and microwave pulses. Their achievement could lay the foundations for a future quantum internet.

Quantum computers are becoming a reality as research labs and companies roll out nascent devices. An important next step in this quantum revolution is creating a “quantum internet” across which quantum information can be shared. The delicate nature of quantum information, however, means that it is very difficult to connect quantum computers over long distances.

Most quantum computers encode quantum bits (qubits) of information into the quantum states of matter – trapped atoms or superconducting circuits, for example. However, the best way to transmit quantum information over long distances is to encode it into a photon of light. An important challenge is how to transfer quantum information from stationary matter-based qubits to photon-based “flying” qubits and then back again.

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Could be made into a generator of some kind :3.

One of the strangest effects to arise from the quantum nature of the universe is the Casimir force. This pushes two parallel conducting plates together when they are just a few dozen nanometres apart.

At these kinds of scales, the Casimir force can dominate and engineers are well aware of its unwanted effects. One reason why microelectromechanical machines have never reached their original promise is the stiction that Casimir forces can generate.

On the other hand, many engineers hope to exploit the Casimir force. Various theoretical models predict that the force should be repulsive between objects of certain shapes, a phenomenon that could prevent stiction.

Continue reading “Engineers Unveil First Casimir Chip That Exploits The Vacuum Energy” | >

High vibrational states of the Magnesium dimer (Mg2) are an important system in studies of fundamental physics, although they have eluded experimental characterization for half a century. Experimental physicists have so far resolved the first 14 vibrational states of Mg2, despite reports that the ground-state may support five additional levels. In a new report, Stephen H. Yuwono and a research team in the departments of physics and chemistry at the Michigan State University, U.S., presented highly accurate initial potential energy curves for the ground and excited electron states of Mg2. They centered the experimental investigations on calculations of state-of-the-art coupled-cluster (CC) and full configuration interaction computations of the Mg2 dimer. The ground-state potential confirmed the existence of 19 vibrational states with minimal deviation between previously calculated rovibrational values and experimentally derived data. The computations are now published on Science Advances and provide guidance to experimentally detect previously unresolved vibrational levels.

Background

Weakly bound alkaline-earth (AE2) dimers can function as probes of fundamental physics phenomena, such as ultracold collisions, doped helium nanodroplets, binary reactions and even optical lattice clocks and quantum gravity. The magnesium dimer is important for such applications since it has several desirable characteristics including nontoxicity and an absence of hyperfine structure in the most abundant 24 Mg isotope that typically facilitates the analysis of binary collisions and other quantum phenomena. However, the status of Mg2 as a prototype heavier AE2 species is complicated since scientists have not been able to experimentally characterize its high vibrational levels and ground-state potential energy curve (PEC) for so long.

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To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the other. Now, researchers at Stevens Institute of Technology have coaxed photons into interacting with one another with unprecedented efficiency — a key advance toward realizing long-awaited quantum optics technologies for computing, communication and remote sensing.

The team, led by Yuping Huang, an associate professor of physics and director of the Center for Quantum Science and Engineering, brings us closer to that goal with a nano-scale chip that facilitates photon interactions with much higher efficiency than any previous system. The new method, reported as a memorandum in the Sept. 18 issue of Optica, works at very low energy levels, suggesting that it could be optimized to work at the level of individual photons — the holy grail for room-temperature quantum computing and secure quantum communication.

“We’re pushing the boundaries of physics and optical engineering in order to bring quantum and all-optical signal processing closer to reality,” said Huang.

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It is a common misconception that quantum computers are not yet ready for applications and the technology still has many years before becoming useful. In this article we will take a look at some of the basic principles of programming a quantum computer and address this misconception. We will look at free, open-source software such as QISKit from IBM, as well as the Quantum Machine Learning software PennyLane. We will also explain how you can run your programs on actual quantum computers in the cloud at IBM. In a follow-up article we will talk about some applications in machine learning that are ready for use currently to anyone with a bit of curiosity.

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Circa 2011 essentially a magnet could be a battery and cpu and a gpu with magnonics.

Harvard physicists have expanded the possibilities for quantum engineering of novel materials such as high-temperature superconductors by coaxing ultracold atoms trapped in an optical lattice — a light crystal — to self-organize into a magnet, using only the minute disturbances resulting from quantum mechanics. The research, published in the journal Nature, is the first demonstration of such a “quantum magnet” in an optical lattice.

As modern technology depends more and more on materials with exotic quantum mechanical properties, researchers are coming up against a natural barrier.

“The problem is that what makes these materials useful often makes them extremely difficult to design,” said senior author Markus Greiner, an associate professor in Harvard’s Department of Physics. “They can become entangled, existing in multiple configurations at the same time. This hallmark of quantum mechanics is difficult for normal computers to represent, so we had to take another approach.”

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Error free qubits o.,o.

Physicists at MIT and elsewhere have observed evidence of Majorana fermions—particles that are theorized to also be their own antiparticle—on the surface of a common metal: gold. This is the first sighting of Majorana fermions on a platform that can potentially be scaled up. The results, published in the Proceedings of the National Academy of Sciences, are a major step toward isolating the particles as stable, error-proof qubits for quantum computing.

In particle physics, fermions are a class of elementary particles that includes electrons, protons, neutrons, and quarks, all of which make up the building blocks of matter. For the most part, these particles are considered Dirac fermions, after the English physicist Paul Dirac, who first predicted that all fermionic fundamental particles should have a counterpart, somewhere in the universe, in the form of an antiparticle—essentially, an identical twin of opposite charge.

In 1937, the Italian theoretical physicist Ettore Majorana extended Dirac’s theory, predicting that among fermions, there should be some particles, since named Majorana fermions, that are indistinguishable from their antiparticles. Mysteriously, the physicist disappeared during a ferry trip off the Italian coast just a year after making his prediction. Scientists have been looking for Majorana’s enigmatic particle ever since. It has been suggested, but not proven, that the neutrino may be a Majorana particle. On the other hand, theorists have predicted that Majorana fermions may also exist in solids under special conditions.

Continue reading “First sighting of mysterious Majorana fermion on a common metal” | >

In nuclear physics, like much of science, detailed theories alone aren’t always enough to unlock solid predictions. There are often too many pieces, interacting in complex ways, for researchers to follow the logic of a theory through to its end. It’s one reason there are still so many mysteries in nature, including how the universe’s basic building blocks coalesce and form stars and galaxies. The same is true in high-energy experiments, in which particles like protons smash together at incredible speeds to create extreme conditions similar to those just after the Big Bang.

Fortunately, scientists can often wield simulations to cut through the intricacies. A represents the important aspects of one system—such as a plane, a town’s traffic flow or an atom—as part of another, more accessible system (like a or a scale model). Researchers have used their creativity to make simulations cheaper, quicker or easier to work with than the formidable subjects they investigate—like proton collisions or black holes.

Simulations go beyond a matter of convenience; they are essential for tackling cases that are both too difficult to directly observe in experiments and too complex for scientists to tease out every logical conclusion from basic principles. Diverse research breakthroughs—from modeling the complex interactions of the molecules behind life to predicting the experimental signatures that ultimately allowed the identification of the Higgs boson—have resulted from the ingenious use of simulations.

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Unlike the magnetic materials used to make a typical memory device, antiferromagnets won’t stick to your fridge. That’s because the magnetic spins in antiferromagnets are oppositely aligned and cancel each other out.

Scientists have long theorized that antiferromagnets have potential as materials for ultrafast stable memories. But no one could figure out how to manipulate their magnetization to read and write information in a device.

Now, a team of researchers at Berkeley Lab and UC Berkeley working in the Center for Novel Pathways to Quantum Coherence in Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, have developed an antiferromagnetic switch for computer memory and processing applications. Their findings, published in the journal Nature Materials, have implications for further miniaturizing computing devices and personal electronics without loss of performance.

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