Equations reveal the rebellious rhythms at the heart of nature

Equations reveal the rebellious rhythms at the heart of nature: Physicists Dmytro Iatsenko , Professor Peter McClintock, and Professor Aneta Stefanovska, have reported a far more general solution of the Kuramoto equations than anyone has achieved previously, with some quite unexpected results.

One surprise is that the oscillators can form "glassy" states, where they adjust the tempos of their rhythms but otherwise remain uncoordinated with each other, thus giving birth to some kind of "synchronous disorder" rather like the disordered molecular structure of window glass. Furthermore and even more astonishingly, under certain circumstances the oscillators can behave in a totally independent manner despite being tightly coupled together, the phenomenon the authors call "super-relaxation".

Create the ultimate world clock with a quantum link - physics-math - 15 June 2014 - New Scientist

Create the ultimate world clock with a quantum link - physics-math - 15 June 2014 - New Scientist: Timekeeping institutes around the world each have their own caesium clocks. They submit their time signal measurements to the International Bureau of Weights and Measures in Paris, France, which averages them and publishes a monthly newsletter that sets Coordinated Universal Time (UTC). But that means there is no real-time measure of a universally agreed standard time...

...The team calculates that a global quantum clock network would be about 100 times more precise than any individual clock...

Synchronized brain waves enable rapid learning | MIT News Office

Synchronized brain waves enable rapid learning | MIT News Office:  Brain waves known as “beta bands,” produced independently by the prefrontal cortex and the striatum, began to synchronize with each other. This suggests that a communication circuit is forming between the two regions, Miller says.

“There is some unknown mechanism that allows these resonance patterns to form, and these circuits start humming together,” he says. “That humming may then foster subsequent long-term plasticity changes in the brain, so real anatomical circuits can form. But the first thing that happens is they start humming together..."

Previous studies have shown that during cognitively demanding tasks, there is increased synchrony between the frontal cortex and visual cortex, but Miller’s lab is the first to show specific patterns of synchrony linked to specific thoughts.

Ultracold Big Bang experiment successfully simulates evolution of early universe

Ultracold Big Bang experiment successfully simulates evolution of early universe: Physicists have reproduced a pattern resembling the cosmic microwave background radiation in a laboratory simulation of the Big Bang, using ultracold cesium atoms in a vacuum chamber at the University of Chicago...


It turns out that under certain conditions, a cloud of atoms chilled to a billionth of a degree above absolute zero (-459.67 degrees Fahrenheit) in a vacuum chamber displays phenomena similar to those that unfolded following the Big Bang, Hung said.

"At this ultracold temperature, atoms get excited collectively. They act as if they are sound waves in air," he said. The dense package of matter and radiation that existed in the very early universe generated similar sound-wave excitations, as revealed by COBE, WMAP and the other experiments.

The synchronized generation of sound waves correlates with cosmologists' speculations about inflation in the early universe. "Inflation set out the initial conditions for the early universe to create similar sound waves in the cosmic fluid formed by matter and radiation," Hung said.

Muscles act as metamaterials due to collective behavior, physicists show

Muscles act as metamaterials due to collective behavior, physicists show: Upon further search for possible mechanisms of negative stiffness, scientists in a new study have found that biological muscles exhibit a mechanical response that also qualifies them as metamaterials: when a tetanized (maximally contracted) muscle is suddenly extended, it comes loose, and if it is suddenly shortened, it tightens up...

Quite surprisingly, the cooperation at the nanoscale in muscles was found to be similar to magnetism; moreover, the critical point at which muscles seem finely tuned to perform near is, in this case, a direct analog of the ferromagnetic Curie point.

Computer simulation shows the sun's "heartbeat" is magnetic

Computer simulation shows the sun's "heartbeat" is magnetic: They ran their simulation on University of Montreal supercomputers which are connected to a larger network across the city. In so doing, they observed that though the sun as a whole experiences an 11 year cycle of solar polar reversals (as noted here on Earth by the periodic nature of observable sun spot activity), zonal magnetic field bands undergo a polarity reversal on average every 40 years.

Nanoscale Device Makes Light Travel Infinitely Fast - ScienceNOW

Nanoscale Device Makes Light Travel Infinitely Fast - ScienceNOW: They've developed a tiny device in which the index of refraction for visible light is zero—so that light waves of a particular wavelength move infinitely fast.

The device consists of a rectangular bar of insulating silicon dioxide 85 nanometers thick and 2000 nanometers long surrounded by conducing silver, which light generally doesn't penetrate. The result is a light-conveying chamber called a waveguide. Researchers fashioned different devices in which the width of the silicon dioxide ranged from 120 to 400 nanometers...

Right at the cutoff wavelength, things get interesting. Instead of producing a banded pattern, the whole waveguide lights up. That means that instead of acting as waves with equally spaced peaks, or "phase fronts," the wave behaves as if its peaks are moving infinitely fast and are everywhere at once. So the light oscillates in synchrony along the length of the waveguide.

Humanoid Robot Swarm Synchronized Using Quorum Sensing� - Technology Review

Humanoid Robot Swarm Synchronized Using Quorum Sensing� - Technology Review: Now Bechon and Slotine say a similar approach provides a robust way to synchronise humanoid robots. The ideal approach  to synchronisation is for each robot to have access to every other robot's position. Instead, the quorum sensing approach gives, each robot  access to a global variable such as the average position or average clock time. Each robot can also change this variable because it contributes to the average.

The idea is that if each robot attempts to synchronise with this global average, the swarm as whole should keep good time.

The Hidden Risk of a Meltdown in the Cloud

The Hidden Risk of a Meltdown in the Cloud: Now Ford imagines the scenario in which both load balancing programs operate with the same refresh period, say once a minute. When these periods coincide, the control loops start sending the load back and forth between the virtual servers in a positive feedback loop.

"The two controllers each compensate with a stronger action causing a larger swing the next minute," says Ford. Clearly, this is a process that must eventually spiral out of control and crash the system.

Not Pulling Your Leg: Tractor Beams May Be Possible

Not Pulling Your Leg: Tractor Beams May Be Possible: The tractor beam would work in a new way. In this case, the light would pull an object toward the source of the beam even though the beam has the same intensity all along its length. The trick is to use a special type of laser beam. In an ordinary beam, each photon moves in the direction of the beam, so when a photon bounces directly back from an object, it imparts the largest possible push. However, physicists can generate a beam by overlapping light waves that make an angle relative to the desired direction (see figure). The overlapping waves produce a forward-moving beam known as a Bessel beam whose intensity remains constant along its length. But each photon is now moving at an angle relative to the beam. So when one bounces off an object, it exerts a smaller forward push.

Nevertheless, the beam is still pushing, and to overcome that push, physicists need to rely on another bit of physics. Again, the light will polarize the material in the object electrically and magnetically. The polarized object will then radiate and redirect the light. By adjusting the material properties of the object and the polarizations and synchronization of the individual light waves in the beam, physicists can make the object radiate more light forward along the beam than backward toward its source. The radiated light then acts like a reverse thruster, overcoming the already-reduced forward push of the beam and driving the object back toward its source.

Flocking Behaviour Improves Performance Of Financial Traders� - Technology Review

Flocking Behaviour Improves Performance Of Financial Traders� - Technology Review: Out of all this seemingly unconnectedness, synchrony still emerges between entirely unrelated trades. Saavreda and co say that 96 per cent of simultaneous trades--those that occur within a second of each other--are of different stocks...
...During the working day, traders constantly message each other through a network that, by law, has to be carefully monitored. Traders use this system to make sense of the news they are receiving...
...It turns out that messaging patterns are positively correlated with the level of synchrony. In other words, as traders exchange more messages, they become more synchronized.

Music of the brain: each synapse has its own natural rhythm | KurzweilAI

Music of the brain: each synapse has its own natural rhythm | KurzweilAI: Contrary to what was previously assumed, Mehta and Kumar found that stimulating the neurons at the highest frequencies was not the best way to increase synaptic strength. “To our surprise, we found that beyond the optimal frequency, synaptic strengthening actually declined as the frequencies got higher.”

The knowledge that a synapse has a preferred frequency for maximal learning led the researchers to compare optimal frequencies based on the location of the synapse on a neuron...

The optimal frequency for inducing synaptic learning changed depending on where the synapse was located. The farther the synapse was from the neuron’s cell body, the higher its optimal frequency.

“Incredibly, when it comes to learning, the neuron behaves like a giant antenna, with different branches of dendrites tuned to different frequencies for maximal learning,” Mehta said.

The Strange Symphony of the Stock Traders - ScienceNOW

The Strange Symphony of the Stock Traders - ScienceNOW: Sociologist Brian Uzzi of Northwestern University in Evanston, Illinois, and colleagues analyzed all trades taking place in a single firm of 66 employees over 2 years. As is usual in trading firms, the employees specialized in different markets—housing, autos, or health care, for example—so they had no obvious incentive to copy one another's behavior. Each trader typically bought or sold stocks about 80 times a day, which the researchers allotted to second-long time windows.

A 7-hour working day is roughly 25,000 seconds, so the chance of one employee's 80 trades randomly synchronizing with any of his colleague's is small. Yet Uzzi's group found that up to 60% of all employees were trading in sync at any one second. What's more, the individual employees tended to make more money during these harmonious bursts, the team reports online this week in the Proceedings of the National Academy of Sciences.

Mastering bandwidth: Researchers develop tunable, low-cost laser device

Mastering bandwidth: Researchers develop tunable, low-cost laser device: The new laser is constructed using microelectromechanical systems (MEMS) technology to achieve wavelength tunability. By moving a tiny mirror, the laser switches between different operating modes, each of which produces a different wavelength. This tuning capability is built into a ‘master’ laser, which injects laser light into a secondary ‘slave’ laser. The slave laser increases the power of the emitted light, suppresses unwanted wavelengths, and allows for the encoding of information by modulating the light intensity. The two-part configuration surpasses the performance of conventional tunable lasers, without increasing bulk or cost.

Particles That Flock: Strange Synchronization Behavior at the Large Hadron Collider: Scientific American

Particles That Flock: Strange Synchronization Behavior at the Large Hadron Collider: Scientific American: "Last summer physicists noticed that some of the particles created by their proton collisions appeared to be synchronizing their flight paths, like flocks of birds. The findings were so bizarre that “we’ve spent all the time since [then] convincing ourselves that what we were see ing was real..." The effect is subtle. When proton collisions result in the release of more than 110 new particles, the scientists found, the emerging particles seem to fly in the same direction.

Moonless Twilight May Cue Mass Spawning - Science News

Moonless Twilight May Cue Mass Spawning - Science News: Just two light-sensing pigments of the opsin type, one tuned to greenish and the other to a blue wavelength, would be enough to detect such a shift, the researchers calculate. In recent genetic analyses, opsin pigments have been showing up in abundance in invertebrates, often more abundantly than in people, Sweeney says.

Marine animals often spawn in sync with some phase of the lunar cycle, and twilight’s color changes slightly around the time of the full moon, Sweeney says. Moonlight has a slight reddish tinge. So the waxing moon, which appears in the sky before the sun sets, shifts twilight a little toward the red. A full moon, however, just peeps over the horizon as the sun sets. As the moon wanes, it rises after sunset, leaving twilight bluer.

Neurobiologists find that weak electrical fields in the brain help neurons fire together

Neurobiologists find that weak electrical fields in the brain help neurons fire together: Extracellular electric fields exist throughout the living brain, though they are particularly strong and robustly repetitive in specific brain regions such as the hippocampus, which is involved in memory formation, and the neocortex, the area where long-term memories are held. "The perpetual fluctuations of these extracellular fields are the hallmark of the living and behaving brain in all organisms, and their absence is a strong indicator of a deeply comatose, or even dead, brain," Anastassiou explains...

An "unexpected and surprising finding was how already very weak extracellular fields can alter neural activity," he says. "For example, we observed that fields as weak as one millivolt per millimeter robustly alter the firing of individual neurons, and increase the so-called "spike-field coherence"—the synchronicity with which neurons fire with relationship to the field."In the mammalian brain, we know that extracellular fields may easily exceed two to three millivolts per millimeter. Our findings suggest that under such conditions, this effect becomes significant."

Neural Feedback: Brain Influences Itself with Its Own Electric Field: Scientific American

Neural Feedback: Brain Influences Itself with Its Own Electric Field: Scientific American: In the study, Yale University neurobiologists David McCormick and Flavio Fröhlich surrounded a still-living slice of ferret brain tissue with an electric field that mimicked the field an intact ferret brain produces during slow-wave sleep. The applied field amplified and synchronized the existing neural activity in the brain slice. These results indicate that the electric field generated by the brain facilitates the same neural firing that created the field in the first place, just as the cloud of enthusiasm that envelops a cheering crowd at a sports stadium encourages the crowd to keep cheering. In other words, the brain’s electric field is not a by-product; it is a feedback loop.

Although researchers knew that periods of highly synchronized neural activity (such as that of deep sleep) are crucial for maintaining normal brain function, exactly how these stable phases are coordinated—and why they go awry in dis orders such as epilepsy—was never clear. The new study indicates scientists may find some answers in the surprisingly active role of the brain’s electric field.

Get in synch — or be enslaved by it | Science Blog

Get in synch — or be enslaved by it | Science Blog: “On one hand, synchronization is necessary for communication and information processing. On the other hand, synchronization can blow violently out of proportion and enslave everything it is in contact with,” explains Ralf Toenjes of Ochanomizu University. He and his colleagues show that adding only a few links to a network can have such a strong effect that even this modest addition can mark the difference between random noise and coherent synchronization. They devised a method of control that enables them to balance the system at states that are actually unstable and usually not observed.

Oscillatory phase coupling coordinates anatomically dispersed functional cell assemblies — PNAS

Oscillatory phase coupling coordinates anatomically dispersed functional cell assemblies — PNAS: Here we show that spiking activity in single neurons and neuronal ensembles depends on dynamic patterns of oscillatory phase coupling between multiple brain areas, in addition to the effects of proximal LFP phase. Neurons that prefer similar patterns of phase coupling exhibit similar changes in spike rates, whereas neurons with different preferences show divergent responses, providing a basic mechanism to bind different neurons together into coordinated cell assemblies. Surprisingly, phase-coupling–based rate correlations are independent of interneuron distance. Phase-coupling preferences correlate with behavior and neural function and remain stable over multiple days. These findings suggest that neuronal oscillations enable selective and dynamic control of distributed functional cell assemblies.