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Archive for the ‘particle physics’ category: Page 181

May 24, 2016

Scientist suggests possible link between primordial black holes and dark matter

Posted by in categories: cosmology, particle physics

Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe’s existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

“This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good,” said Alexander Kashlinsky, an astrophysicist at NASA Goddard. “If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun’s mass.”

In 2005, Kashlinsky led a team of astronomers using NASA’s Spitzer Space Telescope to explore the background glow of infrared light in one part of the sky. The researchers reported excessive patchiness in the glow and concluded it was likely caused by the aggregate light of the first sources to illuminate the universe more than 13 billion years ago. Follow-up studies confirmed that this cosmic infrared background (CIB) showed similar unexpected structure in other parts of the sky.

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May 24, 2016

New evidence could break the standard view of quantum mechanics

Posted by in categories: particle physics, quantum physics

Quantum mechanics is difficult to understand at the best of times, but new evidence suggests that the current standard view of how particles behave on the quantum scale could be very, very wrong.

In fact, the experiment hints that an alternative view predicted almost a century ago might have been right this whole time. And before you get too bummed about that, the good news is that, if confirmed, it would actually make quantum mechanics a whole lot simpler to understand.

So let’s step back for a second here and break this down. First thing’s first, this is just one study, and A LOT more replication and verification would be needed before the standard view comes crumbling down. So don’t go burning any text books just yet, okay? Good.

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May 24, 2016

We can begin an interstellar mission today – and we should

Posted by in categories: particle physics, space travel

Fifty-five years ago, Yuri Gagarin rocketed into orbit and began to break our bonds to our planet. To mark the occasion, the nonprofit Breakthrough Institute just announced plans to free us from an even more formidable set of bonds and send a fleet of small spacecraft beyond our solar system, off to the stars. News of the ‘Breakthrough Starshot’ plan was met with great enthusiasm, but also with more than a little skepticism. The distance between stars is vast. Our closest neighbour, the Alpha Centauri system, is 4.4 light years away – roughly 25 trillion miles. The Voyager 1 spacecraft, the fastest object ever created by humans, would take 70,000 years to travel that far. Many reporters greeted the Breakthrough Starshot as an idea grounded more in fantasy than in reality.

The reaction was understandable. All previous plans for interstellar flight relied on non-existent or impractical technologies such as antimatter, wormholes and warp drives. But now we have a concrete path forward, which I have published in detail. It is possible to begin the journey to the stars today.

Drawing on recent advances in photonics and electronics, we could use arrays of lasers to accelerate miniature probes (the size and mass of a semiconductor wafer, weighing less than one ounce) to unprecedented velocities. Particles of light, or photons, have no rest mass but they carry energy and momentum. Just as a sailboat can be propelled by the wind, light sails can ride the momentum of photons by reflecting a wind of intense laser light. We call such focused beams of light ‘directed energy’.

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May 24, 2016

Precise atom implants in silicon provide a first step toward practical quantum computers

Posted by in categories: computing, particle physics, quantum physics

Nice.


Sandia National Laboratories has taken a first step toward creating a practical quantum computer, able to handle huge numbers of computations instantaneously.

Here’s the recipe:

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May 24, 2016

Where Is New Physics Hiding, And How Can We Find It?

Posted by in categories: cosmology, particle physics

The Standard Models of particle physics and cosmology don’t add up to all there is. What might be the next giant leap forward?

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May 23, 2016

Size quantization of Dirac fermions in graphene

Posted by in categories: electronics, particle physics

Printed Electronics World Tags.

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May 23, 2016

Viewpoint: An Arrested Implosion

Posted by in categories: cosmology, particle physics, quantum physics

The collapse of a trapped ultracold magnetic gas is arrested by quantum fluctuations, creating quantum droplets of superfluid atoms.

Macroscopic implosions of quantum matter waves have now been halted by quantum fluctuations. The quantum wave in question is an atomic Bose-Einstein condensate (BEC), a quantum state with thousands to tens of millions of atoms in an ultracold gas all sharing the same macroscopic wave function. Attractive atomic interactions can cause BECs to collapse in spectacular ways, in what’s been termed a “bosenova,” a lighthearted allusion to a supernova explosion [1]. Tilman Pfau and colleagues from the University of Stuttgart, Germany, have shown that for BECs made of dysprosium, whose bosonic isotopes are among the most magnetic atoms in the periodic table, long-range dipole-dipole interactions between these neutral atoms create a totally new phenomenon: the arrested collapse of a quantum magnetic fluid, called a quantum ferrofluid [2, 3]. Such a ferrofluid relies crucially on the strong dipolar interactions in the dysprosium gas.

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May 19, 2016

New device steps toward isolating single electrons for quantum computing

Posted by in categories: computing, particle physics, quantum physics

Finally, some well deserved recogonition to Argonne Natl. Labs in their efforts on QC with the Univ. Of Chicago.


If biochemists had access to a quantum computer, they could perfectly simulate the properties of new molecules to develop novel drugs in ways that would take the fastest existing computers decades.

Electrons represent an ideal quantum bit, with a “spin” that when pointing up can represent a 0 and down can represent a 1. Such bits are small—even smaller than an atom—and because they do not interact strongly, they can remain quantum for long periods. However, exploiting electrons as qubits also poses a challenge because they must be trapped and manipulated. Which is exactly what David Schuster, assistant professor of physics, and his collaborators at UChicago, Argonne National Laboratory and Yale University have done.

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May 19, 2016

Theorists smooth the way to modeling quantum friction: New paradigm offers a strategy for solving one of quantum mechanics’ oldest problems

Posted by in categories: chemistry, computing, nanotechnology, particle physics, quantum physics

Princeton’s answer to Quantum friction.


Abstract: Theoretical chemists at Princeton University have pioneered a strategy for modeling quantum friction, or how a particle’s environment drags on it, a vexing problem in quantum mechanics since the birth of the field. The study was published in the Journal of Physical Chemistry Letters.

“It was truly a most challenging research project in terms of technical details and the need to draw upon new ideas,” said Denys Bondar, a research scholar in the Rabitz lab and corresponding author on the work.

Quantum friction may operate at the smallest scale, but its consequences can be observed in everyday life. For example, when fluorescent molecules are excited by light, it’s because of quantum friction that the atoms are returned to rest, releasing photons that we see as fluorescence. Realistically modeling this phenomenon has stumped scientists for almost a century and recently has gained even more attention due to its relevance to quantum computing.

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May 18, 2016

Ultrasensitive magnetometer proposed based on compass needle

Posted by in category: particle physics

(Phys.org)—A team of researchers with members from several institutions in the U.S. and one in Germany has proposed the idea of using an extremely small compass needle to build an ultrasensitive magnetometer. In their paper published in Physical Review Letters, the team describes their idea and the possibility of such a device actually being built.

Current magnetometers are very sensitive, able to detect levels of magnetism that are approximately a trillion times less than that of the Earth’s magnetic field. They achieve this feat by taking advantage of the wobble that occurs when an atom is placed in a magnetic field—such magnetometers are made by placing cells of atomic gas in a magnetic field, the wobbles of the are averaged to arrive at a single measurement. In this new effort, the researchers suggest that a new way to measure magnetic fields could be perhaps as much as 1000 times more sensitive.

The idea behind the still theoretically magnetometer comes from the way a compass needle works—instead of wobbling when exposed to a magnetic field, it simply lines up—at least when viewed from a distance. The researchers have shown that such needles do actually wobble like atoms, when they are very small and placed in a very weak magnetic field. They envision a very tiny needle made of cobalt with all of its atoms aligned in a single direction. When the needed is placed in a weak magnetic field, the angular momentum of the rotation of the needle would be a lot smaller than its intrinsic , which means it would precess, very much like single atoms do. Measuring the precess then would offer a means of measuring the level of magnetism.

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