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A new demonstration involving hundreds of entangled atoms tests Schrödinger’s interpretation of Einstein, Rosen, and Podolsky’s classic thought experiment.

In 1935, Einstein, Podolsky, and Rosen (EPR) presented an argument that they claimed implies that quantum mechanics provides an incomplete description of reality [1]. The argument rests on two assumptions. First, if the value of a physical property of a system can be predicted with certainty, without disturbance to the system, then there is an “element of reality” to that property, meaning it has a value even if it isn’t measured. Second, physical processes have effects that act locally rather than instantaneously over a distance. John Bell subsequently proposed a way to experimentally test these “local realism” assumptions [2], and so-called Bell tests have since invalidated them for systems of a few small particles, such as electrons or photons [3].

An unusual kind of superconductor harbors magnetic vortices that researchers predict should be readily observable thanks to the striped configurations they adopt.

In a nematic superconductor, electron pairs are bound more strongly in one, spontaneously chosen, lattice direction than in the others. This rotational symmetry breaking of the pairs’ wave function is just one of this type of superconductor’s unusual properties. A leading candidate to exhibit nematic superconductivity, copper-doped bismuth selenide, is also predicted to sustain surface charge-carrying quasiparticles known as Majorana fermions, which researchers think could be used for superconducting quantum technologies. What’s more, nematic superconductors harbor topological solitons known as skyrmions, whose complexity gives them many ways to arrange themselves and whose small size and low energy have attracted interest for data storage technologies. Now Thomas Winyard of the University of Edinburgh, UK, and colleagues have calculated the various skyrmion configurations that could arise in a nematic superconductor [1, 2].

The physicist Tony Skyrme came up with the concept of a skyrmion in 1961 when working on a particle physics problem. In the 2000s, the quasiparticle was then linked to condensed-matter systems when it was discovered that quasiparticles could also be used to explain magnetic vortices in certain thin films.

“” This achievement connects synchrotron X-rays with quantum tunneling process to detect X-ray signature of an individual atom and opens many exciting research directions including the research on quantum and spin (magnetic) properties of just one atom using synchrotron X-rays,” Hla said.”

A team of scientists from Ohio University, Argonne National Laboratory, the University of Illinois-Chicago, and others, led by Ohio University Professor of Physics, and Argonne National Laboratory scientist, Saw Wai Hla, have taken the world’s first X-ray SIGNAL (or SIGNATURE) of just one atom. This groundbreaking achievement could revolutionize the way scientists detect the materials.

There is a lot of speculation about the end of the universe. Humans love a good ending after all. We know that the universe started with the Big Bang and it has been going for almost 14 billion years. But how the curtain call of the cosmos occurs is not certain yet. There are, of course, hypothetical scenarios: the universe might continue to expand and cool down until it reaches absolute zero, or it might collapse back onto itself in the so-called Big Crunch. Among the alternatives to these two leading theories is “vacuum decay”, and it is spectacular – in an end-of-everything kind of way.

While the heat death hypothesis has the end slowly coming and the Big Crunch sees a reversal of the universe’s expansion at some point in the future, the vacuum decay requires that one spot of the universe suddenly transforms into something else. And that would be very bad news.

There is a field that spreads across the universe called the Higgs field. Interaction between this field and particles is what gives the particles mass. A quantum field is said to be in its vacuum state if it can’t lose any energy but we do not know if that’s true for the Higgs field, so it’s possible that the field is in a false vacuum at some point in the future. Picture the energy like a mountain. The lowest possible energy is a valley but as the field rolled down the slopes it might have encountered a small valley on the side of that mountain and got stuck there.

Neil Gershenfeld is the director of the MIT Center for Bits and Atoms. Please support this podcast by checking out our sponsors:
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EPISODE LINKS:
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Continue reading “Neil Gershenfeld: Self-Replicating Robots and the Future of Fabrication | Lex Fridman Podcast #380” »

Physicist Sean Carroll explains the discovery of Higgs Boson in simple terms. Credit-ICE at Dartmouth.

Particle-like quantum states called non-abelian anyons remember being swapped and could be useful for protecting information in quantum computers.

The atoms in a piece of sapphire oscillate in two directions at once, a mimic of the hypothetically dead-and-alive feline.

Light is a key carrier of information. It enables high-speed data transmission around the world via fiber-optic telecommunication networks. This information-carrying capability can be extended to transmitting quantum information by encoding it in single particles of light (photons).

“To efficiently load single photons into quantum information processing devices, they must have specific properties: the right central wavelength or frequency, a suitable duration, and the right spectrum,” explains Dr. Michał Karpinski, head of the Quantum Photonics Laboratory at the Faculty of Physics of the University of Warsaw, and an author of the paper published in Nature Photonics.

Researchers around the globe are building prototypes of quantum computers using a variety of techniques, including trapped ions, quantum dots, superconducting electric circuits, and ultracold atomic clouds. These quantum information processing platforms operate on a variety of time scales, from picoseconds through nanoseconds to even microseconds.