Big Bang breakthrough team back-pedals on major result - physics-math - 19 June 2014 - New Scientist

Big Bang breakthrough team back-pedals on major result - physics-math - 19 June 2014 - New Scientist: The paper published today is significant because it is the first time the researchers themselves have dialled back on their original claims...

"It seems that real data from Planck is indicating that these dust models are under-estimates," says Pryke. "The prior knowledge of dust at these latitudes in our field of view has gone up and so the confidence in the gravitational wave component has gone down."

Blockbuster Big Bang Result May Fizzle, Rumor Suggests | Science/AAAS | News

Blockbuster Big Bang Result May Fizzle, Rumor Suggests | Science/AAAS | News: To subtract the galactic foreground, BICEP researchers relied on a particular map of it generated by the European Space Agency's spacecraft Planck, which mapped the CMB across the entire sky from 2009 until last year. However, the BICEP team apparently interpreted the map as showing only the galactic emissions. In reality, it may also contain the largely unpolarized hazy glow from other galaxies, which has the effect of making the galactic microwaves coming from any particular point of the sky look less thoroughly polarized than they actually are. So using the map to strip out the galactic foreground may actually leave some of that foreground in the data where it could produce a spurious signal, Falkowski explains.

New ‘switch’ could power quantum computing | MIT News Office

New ‘switch’ could power quantum computing | MIT News Office:  “We have demonstrated basically an atom can switch the phase of a photon. And the photon can switch the phase of an atom...”

In this case, the researchers used a laser to place a rubidium atom very close to the surface of a photonic crystal cavity, a structure of light. The atoms were placed no more than 100 or 200 nanometers — less than a wavelength of light — from the edge of the cavity. At such small distances, there is a strong attractive force between the atom and the surface of the light field, which the researchers used to trap the atom in place...

“In some sense, it was a big surprise how simple this solution was compared to the different techniques you might envision of getting the atoms there,” Vuletić says.

Cosmologists Say Last Week’s Announcement About Gravitational Waves and Inflation May Be Wrong — The Physics arXiv Blog — Medium

Cosmologists Say Last Week’s Announcement About Gravitational Waves and Inflation May Be Wrong — The Physics arXiv Blog — Medium: Many cosmologists think that the same kind of phases changes occurred in the universe after inflation. Each phase change began in different regions at slightly different times...

This self-ordering process would have been hugely violent, generating its own gravitational waves that rippled through spacetime, albeit after inflation. Could this process be responsible for the polarisation that the BICEP2 team has measured?...

...a small improvement in the data could firmly rule out self-ordering as the origin of the signal.

First glimpse of big bang ripples from universe's birth - physics-math - 17 March 2014 - New Scientist

First glimpse of big bang ripples from universe's birth - physics-math - 17 March 2014 - New Scientist: Inflation should have stretched the very first gravitational waves created during the big bang, taking them from imperceptible wavelengths to a size we can detect in the CMB... Rippling gravitational waves would subtly change the polarisation pattern, twisting the CMB into distinctive swirls called B-modes...

"We see a big excess of power, and it looks exactly like the gravitational wave signal that we had been seeking," says Pryke. "There's a huge zoo of inflationary models, but if we look at the simplest ones, they would predict values in the ballpark that we're seeing..."

"If gravity were not quantised, inflation would not produce gravitational waves," says Guth.

The symphony of life, revealed - News Center

The symphony of life, revealed - News Center: Using a technique they developed based on terahertz near-field microscopy, scientists... have for the first time observed in detail the vibrations of lysozyme, an antibacterial protein found in many animals.

The team found that the vibrations, which were previously thought to dissipate quickly, actually persist in molecules like the “ringing of a bell...”

To observe the protein vibrations, Markelz’ team relied on an interesting characteristic of proteins: The fact that they vibrate at the same frequency as the light they absorb...

Markelz and her colleagues exposed a sample to light of different frequencies and polarizations, and measured the types of light the protein absorbed.

New generation laser will herald technological breakthrough

New generation laser will herald technological breakthrough: In a paper recently published in Physical Review B, researchers from the Department of Physics demonstrate their work into bosonic lasers which emit terahertz radiation.
Such lasers have been around for years, commonly found in satellites, for environmental monitoring, astronomy, security and non-destructive testing, imaging, and medical applications. But they are considered bulky, impractical and expensive.

Fastest rotating man-made object created

Fastest rotating man-made object created: To do this they manufactured a microscopic sphere of calcium carbonate only 4 millionths of a metre in diameter. The team then used the miniscule forces of laser light to hold the sphere with the radiation pressure of light...
They exploited the property of polarisation of the laser light that changed as the light passed through the levitating sphere, exerting a small twist or torque.
Placing the sphere in vacuum largely removed the drag (friction) due to any gas environment, allowing the team to achieve the very high rotation rates...

"I am intrigued with the prospect of extending this to multiple trapped particles and rotating systems. We may even be able to shed light on the area of quantum friction – that is – does quantum mechanics put the brakes on the motion or spinning particle even though we are in a near perfect vacuum with no other apparent sources of friction?"

How neurons ‘decide’ to create axons or dendrites | KurzweilAI

How neurons ‘decide’ to create axons or dendrites | KurzweilAI: They found that embryonic nerve cells manufacture a signaling enzyme called Atypical Protein Kinase C (aPKC) in two varieties: a full-length one and a shorter one...
When the researchers blocked the production of the short form, the nerve cell grew multiple axons and no dendrites. When they created an artificial abundance of the short form, dendrites formed at the expense of axons.

Quantum teleportation approaches the computer chip | Matter & Energy | Science News

Quantum teleportation approaches the computer chip | Matter & Energy | Science News; Now physicist Andreas Wallraff at ETH Zurich and his team have created the first solid-state device, similar to a computer chip, that is capable of teleporting quantum information. The chip contains tiny circuits that each behave like an atom. The circuits are connected by millimeters-long transmission lines carrying microwave radiation, which entangles the circuits so that the properties of one affect the other. By programming a bit of quantum information into circuit A, Wallraff and his team changed the signal arriving at circuit B. They could then use that changed signal to determine the original properties of circuit A and transfer them to circuit B.

Most importantly, Wallraff’s teleportation system successfully transports information in nearly every attempt, and it can do it roughly 10,000 times per second, an unprecedented rate.

Twisted Magnetic Fields Tie Information in a Knot: Scientific American

Twisted Magnetic Fields Tie Information in a Knot: Scientific American: Writing in Science, von Bergmann and her collaborators describe how they created skyrmions on a thin magnetic film of palladium and iron on an iridium crystal. They began with a sample in which all the atomic bar magnets were aligned. The team then used the tip of a scanning tunnelling microscope to apply a small current made up of electrons that had their spins aligned, or polarized, in a particular way. The polarized current interacted with the atomic bar magnets to twist them into knot-like configurations of skyrmions, each a few nanometers, or about 300 atoms, in diameter, says von Bergmann. The scientists could also use the polarized current to erase the knot, deleting the skyrmion...

...this is the first time that scientists have created and deleted individual magnetic skyrmions...

Swirls in the Afterglow of the Big Bang Could Set Stage for Major Discovery | Science/AAAS | News

Swirls in the Afterglow of the Big Bang Could Set Stage for Major Discovery | Science/AAAS | News . In a patch of sky, the random polarization pattern can be separated into two superimposed components: B-modes, in which the polarization forms right- or left-handed swirls, and E-modes, in which it does not. Whereas the coalescing of matter in the early universe can produce only E-modes, gravity waves rippling along during inflation should produce B-modes. The intensity of those "primordial" B-modes should reveal the energy density of the universe during inflation and help explain how it happened.

Physicists Create Quantum Link Between Photons That Don't Exist at the Same Time

Physicists Create Quantum Link Between Photons That Don't Exist at the Same Time: They start with a scheme known as entanglement swapping. To begin, researchers zap a special crystal with laser light a couple of times to create two entangled pairs of photons, pair 1 and 2 and pair 3 and 4. At the start, photons 1 and 4 are not tangled. But they can be if physicists play the right trick with 2 and 3.

The key is that a measurement "projects" a particle into a definite state -- just as the measurement of a photon collapses it into either vertical or horizontal polarization. So even though photons 2 and 3 start out unentangled, physicists can set up a "projective measurement" that asks, are the two in one of two distinct entangled states or the other? That measurement entangles the photons, even as it absorbs and destroys them. If the researchers select only the events in which photons 2 and 3 end up in, say, the first entangled state, then the measurement also entangles photons 1 and 4. (See diagram, top.) The effect is a bit like joining two pairs of gears to form a four-gear chain: Enmeshing to inner two gears establishes a link between the outer two.

In recent years, physicists have played with the timing in the scheme. For example, last year a team showed that entanglement swapping still works even if they make the projective measurement after they've already measured the polarizations of photons 1 and 4. Now, Eisenberg and colleagues have shown that photons 1 and 4 don't even have to exist at the same time, as they report in a paper in press at Physical Review Letters.

To do that, they first create entangled pair 1 and 2 and measure the polarization of 1 right away. Only after that do they create entangled pair 3 and 4 and perform the key projective measurement. Finally, they measure the polarization of photon 4. And even though photons 1 and 4 never coexist, the measurements show that their polarizations still end up entangled. Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting.

First Demonstration of the Storage And Release of Light in a Metamaterial

First Demonstration of the Storage And Release of Light in a Metamaterial: In this case, Nakanishi and co have created a metamaterial in which each repeating unit contains two variable capacitors. One of the capacitors is designed to absorb and radiate waves at a particular frequency while the other is designed to trap them.

If the capacitors are tuned to the same frequency, any light at that frequency is absorbed and trapped. Detuning the capacitors then releases the electromagnetic waves, allowing them to continue on their way...


What’s more impressive, however, is that the released waves have the same phase distribution as the originals. “The electromagnetic waves were stored and released, while maintaining the phase distribution in the propagating direction,” they say.

Turning Pull Into Push? - ScienceNOW

Turning Pull Into Push? - ScienceNOW: To see how this scenario works, consider the case in which just a point charge moves across the surface of an insulator. In that case, the polarization pattern moves with it, becoming so-called evanescent waves that still attract the point charge.

If the point charge moves fast enough, another factor comes into play. In an insulating material such as glass, light travels slower than in empty space. And if a charge moves through the glass faster than light can, it creates a shockwave of light, known as Cherenkov radiation, much like the sonic boom from a supersonic jet. Now, if a point charge above the insulator whizzes along faster than light can within the material, then the induced polarization pattern will move that fast as well and create Cherenkov radiation. That radiation flows at an angle down into the material and carries momentum with it. But by Newton's law that every action has an equal and opposite reaction, the downward flow of momentum must be balanced by an upward push on the point charge.

Quantum Teleportation Achieved over Record Distances

Quantum Teleportation Achieved over Record Distances:  In a paper posted May 17 to the physics preprint Web site arXiv.org, just eight days after the Chinese group announced their achievement on the same Web site, a European and Canadian group claims to have teleported information from one of the Canary Islands to another, 143 kilometers away. That paper has not been peer-reviewed but comes from a very reputable research group.

Dark matter, dark energy, dark… magnetism?

Dark matter, dark energy, dark… magnetism?:   In 2008 at the Complutense University of Madrid, Spain, they were playing with a particular version of a mutant gravity model called a vector-tensor theory, which they had found could mimic dark energy. Then came a sudden realisation. The new theory was supposed to be describing a strange version of gravity, but its equations bore an uncanny resemblance to some of the mathematics underlying another force. "They looked like electromagnetism," says Beltrán, now based at the University of Geneva in Switzerland. "We started to think there could be a connection."

So they decided to see what would happen if their mathematics described not masses and space-time, but magnets and voltages...

Crucially, inflation could also have boosted the new electromagnetic waves. Beltrán and Maroto found that this process would leave behind vast temporal modes: waves of electric potential with wavelengths many orders of magnitude larger than the observable universe. These waves contain some energy but because they are so vast we do not perceive them as waves at all.

Pigeons may ‘hear’ magnetic fields : Nature News & Comment

Pigeons may ‘hear’ magnetic fields : Nature News: Individual neurons in birds' brains can relay crucial information about Earth’s magnetic field...

For their latest research, the subject of today's Science paper, Wu and Dickman restrained seven homing pigeons (Columba livia) and placed them in a dark room. A magnetic field was created to cancel Earth’s field, and the researchers then monitored the birds’ brain activity while creating and rotating carefully controlled artificial magnetic fields around the pigeons.

The authors found that vestibular neurons — which are linked to balance systems in the inner ear — fired differentially in response to alterations in the field’s direction, intensity and polarity, and that these cells were especially sensitive to the bandwith that covers Earth’s geo-magnetic field...

“I would say now there are three potential places where magnetoreceptors may rest...”  These are the beak, the eyes and the ears.

Molecular "Wankel Engine" Driven By Photons

Molecular "Wankel Engine" Driven By Photons: A couple of year ago, chemists discovered that groups of 13 or 19 boron molecules form into concentric rings that can rotate independently, rather like the piston in a rotary Wankel engine. Because of this, they quickly picked up the moniker "molecular Wankel engines". The only question was how to power them.

Now Zhang and buddies have calculated that this should be remarkably easy--just zap them with circularly polarised infrared light. That sets the inner ring counter-rotating relative the outer one, like a Wankel engine...
What makes this one special is that the polarised light doesn't excite the molecule's electronic ground state,  leaving it free to be chemically active.

Ants can learn vibrational and magnetic landmarks

Ants can learn vibrational and magnetic landmarks: Trained ants of the species Cataglyphis noda pinpointed their nest without any problem if a battery-powered vibrational device was buried next to the nest entrance so that the ants could localize their nest by using the vibrational landmark. To exclude electromagnetic effects of the device, experiments were performed using the vibrational device without contact to the ground. The result: The ants behaved like their untrained conspecifics. They wandered around aimlessly. If two strong neodym magnets generating a magnetic field of about 21 millitesla (the earth’s magnetic field was, for comparison, only 0.041 millitesla) were placed above ground next to the nest, trained ants again found their home without any problems.