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Archive for the ‘quantum physics’ category: Page 846

Oct 18, 2015

A New Experiment May Determine Whether Gravity Is Quantized

Posted by in categories: particle physics, quantum physics

In physics there are two broad ways to look at the world. One is the classical realm of Newton and Einstein, where objects have definite form and interact in clearly determinate ways. The other is the quantum realm, where objects seem nebulous, with a strange mix of particle-like and wave-like behavior. The classical view gives us a wonderfully accurate description of everything from planets to baseballs. The quantum view is necessary to accurately describe the behavior of light and atoms. The classical world dominates on the scale of our daily lives, but nature seems to be rooted in quantum theory at its most basic level.

While both the classical and quantum approach are extremely accurate in their respective regimes, what happens in the intersection of the two regimes is still unclear. We don’t have a rigorous theory combining our classical and quantum models. We also don’t have certain key observational evidence, particularly in the nexus of quantum theory and gravity. But as quantum experiments increasingly study more massive objects and gravity experiments become increasingly sensitive, we’re approaching the point where “quantum gravity” experiments could be made. That’s the goal of a recently proposed experiment.

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Oct 15, 2015

Researchers use engineered viruses to provide quantum-based enhancement of energy transport

Posted by in categories: bioengineering, genetics, particle physics, quantum physics, solar power, sustainability

Nature has had billions of years to perfect photosynthesis, which directly or indirectly supports virtually all life on Earth. In that time, the process has achieved almost 100 percent efficiency in transporting the energy of sunlight from receptors to reaction centers where it can be harnessed—a performance vastly better than even the best solar cells.

One way plants achieve this efficiency is by making use of the exotic effects of quantum mechanics—effects sometimes known as “quantum weirdness.” These effects, which include the ability of a particle to exist in more than one place at a time, have now been used by engineers at MIT to achieve a significant efficiency boost in a light-harvesting system.

Surprisingly, the MIT researchers achieved this new approach to solar energy not with high-tech materials or microchips—but by using genetically engineered viruses.

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Oct 12, 2015

A newly proposed table-top experiment might be able to demonstrate that gravity is quantized

Posted by in categories: particle physics, quantum physics

Tl;dr: Experimentalists are bringing increasingly massive systems into quantum states. They are now close to masses where they might be able to just measure what happens to the gravitational field.

Quantum effects of gravity are weak, so weak they are widely believed to not be measurable at all. Freeman Dyson indeed is fond of saying that a theory of quantum gravity is entirely unnecessary, arguing that we could never observe its effects anyway. Theorists of course disagree, and not just because they’re being paid to figure out the very theory Dyson deems unnecessary. Measurable or not, they search for a quantized version of gravity because the existing description of nature is not merely incomplete – it is far worse, it contains internal contradictions, meaning we know it is wrong.

Take the century-old double-slit experiment, the prime example for quantum behavior. A single electron that goes through the double-slit is able to interact with itself, as if it went through both slits at once. Its behavior is like that of a wave which overlaps with itself after passing an obstacle. And yet, when you measure the electron after it went through the slit it makes a dot on a screen, like a particle would. The wave-like behavior again shows up if one measures the distribution of many electrons that passed the slit. This and many other experiments demonstrate that the electron is neither a particle nor a wave – it is described by a wave-function from which we obtain a probability distribution, a formulation that is the core of quantum mechanics.

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Oct 10, 2015

Physicists say energy can be teleported ‘without a limit of distance’

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

A team of physicists has proposed a way of teleporting energy over long distances. The technique, which is purely theoretical at this point, takes advantage of the strange quantum phenomenon of entanglement where two particles share the same existence.

The researchers, who work out of Tohoku University in Japan, and led by Masahiro Hotta,describe their proposal in the latest edition of Physical Review A. Their system exploits properties of squeezed light or vacuum states that should allow for the teleportation of information about an energy state. In turn, this teleported quantum energy could be made useable.

Unlike teleportation schemes as portrayed in Star Trek or The Fly, this type of teleportation describes entanglement experiments in which two entangled particles are joined despite no apparent connection between them. When a change happens to one particle, the same change happens to the other. Hence, the impression of teleportation. Physicists have conducted experiments using light, matter, and now, energy.

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Oct 9, 2015

Scientists paint quantum electronics with beams of light

Posted by in categories: computing, electronics, materials, quantum physics

A team of scientists from the University of Chicago and the Pennsylvania State University have accidentally discovered a new way of using light to draw and erase quantum-mechanical circuits in a unique class of materials called topological insulators.

In contrast to using advanced nanofabrication facilities based on chemical processing of materials, this flexible technique allows for rewritable ‘optical fabrication’ of devices. This finding is likely to spawn new developments in emerging technologies such as low-power electronics based on the spin of electrons or ultrafast quantum computers.

The research is published today in the American Association for the Advancement of Science’s new online journal Science Advances, where it is featured on the journal’s front page.

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Oct 8, 2015

Scientists float new approach to creating computer memory

Posted by in categories: computing, quantum physics

What can skyrmions do for you? These ghostly quantum rings, heretofore glimpsed only under extreme laboratory conditions, just might be the basis for a new type of computer memory that never loses its grip on the data it stores.

Now, thanks to a research team including scientists from the National Institute of Standards and Technology (NIST), the exotic ring-shaped magnetic effects have been coaxed out of the physicist’s deepfreeze with a straightforward method that creates magnetic skyrmions under ambient room conditions. The achievement brings skyrmions a step closer for use in real-world data storage as well as other novel magnetic and electronic technologies.

If you have a passing familiarity with particle physics, you might expect skyrmions to be particles; after all, they sound a lot like fermions, a class of particles that includes protons and neutrons. But skyrmions are not fundamental pieces of matter (not even of yogurt); they are effects named after the physicist who proposed them. Until just recently, magnetic skyrmions had only been seen at very low temperatures and under powerful magnetic fields.

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Oct 8, 2015

Entanglement: Gravity’s long-distance connection

Posted by in categories: computing, cosmology, quantum physics

Many researchers find these ideas irresistible. Within the last few years, physicists in seemingly unrelated specialties have converged on this confluence of entanglement, space and wormholes. Scientists who once focused on building error-resistant quantum computers are now pondering whether the universe itself is a vast quantum computer that safely encodes spacetime in an elaborate web of entanglement. “It’s amazing how things have been progressing,” says Van Raamsdonk, of the University of British Columbia in Vancouver.

Physicists have high hopes for where this entanglement-spacetime connection will lead them. General relativity brilliantly describes how spacetime works; this new research may reveal where spacetime comes from and what it looks like at the small scales governed by quantum mechanics. Entanglement could be the secret ingredient that unifies these supposedly incompatible views into a theory of quantum gravity, enabling physicists to understand conditions inside black holes and in the very first moments after the Big Bang.

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Oct 7, 2015

Can quantum physics explain irrational decisions? — By Leslie D’Monte | Livemint

Posted by in category: quantum physics

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“Thinking in a quantum-like way lets people confront complex questions.”

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Oct 6, 2015

Crucial hurdle overcome in quantum computing

Posted by in categories: computing, quantum physics

The significant advance, by a team at the University of New South Wales (UNSW) in Sydney appears today in the international journal Nature.

“What we have is a game changer,” said team leader Andrew Dzurak, Scientia Professor and Director of the Australian National Fabrication Facility at UNSW.

“We’ve demonstrated a two-qubit logic gate — the central building block of a quantum computer — and, significantly, done it in . Because we use essentially the same device technology as existing computer chips, we believe it will be much easier to manufacture a full-scale processor chip than for any of the leading designs, which rely on more exotic technologies.

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Oct 5, 2015

Australian engineers just built a quantum logic gate in silicon for the first time

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

For decades, researchers have been trying to build a computer that harnesses the enormous potential of quantum mechanics. Now engineers from the University of New South Wales (UNSW) in Australia have overcome the final hurdle, by creating a quantum logic gate in silicon — the same material that today’s computer chips are made from.

The newly developed device allows two quantum bits — or qubits — to communicate and perform calculations together, which is a crucial requirement for quantum computers. Even better, the researchers have also worked out how to scale the technology up to millions of qubits, which means they now have the ability to build the world’s first quantum processor chip and, eventually, the first silicon-based quantum computer.

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