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A new research project aims to harness the power of quantum computers to build a new type of neural network — work the researchers say could usher in the next generation of artificial intelligence.

“My colleagues and I instead hope to build the first dedicated neural network computer, using the latest ‘quantum’ technology rather than AI software,” wrote Michael Hartmann, a professor at Heriot-Watt University who’s leading the research, in a new essay for The Conversation. “By combining these two branches of computing, we hope to produce a breakthrough which leads to AI that operates at unprecedented speed, automatically making very complex decisions in a very short time.”

A team of researchers at Utrecht University, the Norwegian University of Science and Technology and the University of Konstanz has recently proposed a new method to determine magnon coherence in solid-state devices. Their study, outlined in a paper published in Physical Review Letters, shows that cross-correlations of pure spin currents injected by a ferromagnet into two metal leads normalized by their dc value replicate the behavior of the second-order optical coherence function, referred to as g, when magnons are driven far from equilibrium.

“Consider a big room full of people having a party,” Akash Kamra, one of the researchers who carried out the study, told Phys.org. “These people can either behave as in a night club, bumping into each other in an uncoordinated way and with chaotic movements, or the party people might be directed by a common host, such as at a wedding party. Such a ‘condensed’ crowd of people moves swiftly without bumping into each other.”

Kamra draws an analogy between the party situations he described and magnons, quantum particles that correspond to a specific decrease in magnetic strength, traveling as a unit through a magnetic substance. In his analogy, an uncoordinated “party” would occur if magnons are in a “thermal” state, while a coordinated one if they are in a “coherent” or “condensed” state. The coordinated movement of guests in the second type of party, on the other hand, would correspond to a superfluid flow, which is a manifestation of a remarkable state of matter: the condensate.

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…our techniques may enable quantum enhanced AIs to learn the effect of their actions much more efficiently.

Researchers at the University of Queensland (UQ) have produced what may very well be the first pieces of art made using non-classical matter. The team has reproduced famous artworks like the Mona Lisa and Starry Night on a “quantum canvas” as small as a human hair, by projecting light onto Bose-Einstein condensates (BECs).

VIENNA—Over the past several days, I attended a fascinating conference that explored an old idea of Einstein’s, one that was largely dismissed for decades: that quantum mechanics is not the root level of reality, but merely a hazy glimpse of something even deeper.

• By George Musser on October 7, 2013

Quantum information protocols require various types of entanglement, such as Einstein-Podolsky-Rosen, Greenberger-Horne-Zeilinger, and cluster states. In optics, on-demand preparation of these states has been realized by squeezed light sources, but such experiments require different optical circuits for different entangled states, thus lacking versatility. Here, we demonstrate an on-demand entanglement synthesizer that programmably generates all these entangled states from a single squeezed light source. This is achieved by a loop-based circuit that is dynamically controllable at nanosecond time scales and processes optical pulses in the time domain. We verify the generation of five different small-scale entangled states and a large-scale cluster state containing more than 1000 modes without changing the optical circuit. Moreover, this circuit enables storage and release of one part of the generated entangled state, thus working as a quantum memory. Our demonstration should open a way for a more general entanglement synthesizer and a scalable quantum processor.

Entanglement is an essential resource for many quantum information protocols in both qubit and continuous variable (CV) regimes. However, different types of entanglement are required for different applications (Fig. 1A). The most commonly used maximally entangled state is a two-mode Einstein-Podolsky-Rosen (EPR) state (1), which is the building block for two-party quantum communication and quantum logic gates based on quantum teleportation (2, 3). Its generalized version is an n-mode Greenberger-Horne-Zeilinger (GHZ) state (4, 5), which is central to building a quantum network; this state, once shared between n parties, enables any two of the n parties to communicate with each other (5, 6). In terms of quantum computation, a special type of entanglement called cluster states has attracted much attention as a universal resource for one-way quantum computation (7–9).

Protons are complicated. The subatomic particles are themselves composed of smaller particles called quarks and gluons. Now, data from the Large Hadron Collider hint that protons’ constituents don’t behave independently. Instead, they are tethered by quantum links known as entanglement, three physicists report in a paper published April 26 at arXiv.org.

Quantum entanglement has previously been probed on scales much larger than a proton. In experiments, entangled particles seem to instantaneously influence one another, sometimes even when separated by distances as large as thousands of kilometers (SN: 8/5/17, p. 14). Although scientists suspected that entanglement occurs within a proton, signs of that phenomenon hadn’t been experimentally demonstrated inside the particle, which is about a trillionth of a millimeter across.

“The idea is, this is a quantum mechanical particle which, if you look inside it, … it’s itself entangled,” says theoretical physicist Piet Mulders of Vrije Universiteit Amsterdam, who was not involved with the research.

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They started their experiment with a different goal in mind.

A prime number theory equation by mathematics professor emeritus Carl Pomerance turned up on The Big Bang Theory, where it was scrawled on a white board in the background of the hit sitcom about a group of friends and roommates who are scientists, many of them physicists at the California Institute of Technology.

In a recent paper, “Proof of the Sheldon Conjecture,” Pomerance, the John G. Kemeny Parents Professor of Mathematics Emeritus, does the math on a claim by fictional quantum physicist Sheldon Cooper that 73 is “the best number” because of several unique properties. Pomerance’s proof shows that 73 is indeed unique.

The Big Bang Theory is known for dressing the set with “Easter eggs” to delight the self-avowed science nerds in the audience. When UCLA physics professor David Saltzberg, technical consultant for The Big Bang Theory, heard about the Sheldon proof, he contacted Pomerance to ask if they could use it in the show, which was broadcast April 18.

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