An international team led by researchers at Nagoya University, along with U.S. and Swiss colleagues, has identified a new type of solar event and dated it to the year 5480 BC; they did this by measuring carbon-14 levels in tree rings, which reflect the effects of cosmic radiation on the atmosphere at the time. They have also proposed causes of this event, thereby extending knowledge of how the sun behaves.
When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called ‘carbon-14’ increases in the earth’s atmosphere. Because trees absorb carbon in the air, carbon-14 levels in tree rings actually reflect solar activity and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.
“We measured the 14C levels in the pine sample at three different laboratories in Japan, the U.S., and Switzerland to ensure the reliability of our results,” A. J. Timothy Jull of the University of Arizona says. “We found a change in 14C that was more abrupt than any found previously, except for cosmic ray events in AD 775 and AD 994, and our use of annual data rather than data for each decade allowed us to pinpoint exactly when this occurred.”
The team attempted to develop an explanation for the anomalous solar activity data by comparing the features of the 14C change with those of other solar events known to have occurred over the last couple of millennia.
“Although this newly discovered event is more dramatic than others found to date, comparisons of the 14C data among them can help us to work out what happened to the sun at this time,” Fusa Miyake of Nagoya University says. She adds, “We think that a change in the magnetic activity of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data.”
Although the poor understanding of the mechanisms behind unusual solar activity has hampered efforts to definitively explain the team’s findings, they hope that additional studies, such as telescopic findings of flares given off by other sun-like stars, could lead to an accurate explanation.
Study Reveals Substantial Evidence of Holographic Universe
A UK, Canadian and Italian study has provided what researchers believe is the first observational evidence that our universe could be a vast and complex hologram.
Theoretical physicists and astrophysicists, investigating irregularities in the cosmic microwave background (the ‘afterglow’ of the Big Bang), have found there is substantial evidence supporting a holographic explanation of the universe—in fact, as much as there is for the traditional explanation of these irregularities using the theory of cosmic inflation.
The researchers, from the University of Southampton (UK), University of Waterloo (Canada), Perimeter Institute (Canada), INFN, Lecce (Italy) and the University of Salento (Italy), have published findings in the journal Physical Review Letters.
A holographic universe, an idea first suggested in the 1990s, is one where all the information that makes up our 3D ‘reality’ (plus time) is contained in a 2D surface on its boundaries.
Professor Kostas Skenderis of Mathematical Sciences at the University of Southampton explains: “Imagine that everything you see, feel, and hear in three dimensions (and your perception of time) in fact emanates from a flat two-dimensional field. The idea is similar to that of ordinary holograms where a three-dimensional image is encoded in a two-dimensional surface, such as in the hologram on a credit card. However, this time, the entire universe is encoded!”
Although not an example with holographic properties, it could be thought of as rather like watching a 3D film in a cinema. We see the pictures as having height, width and crucially, depth—when in fact it all originates from a flat 2D screen. The difference, in our 3D universe, is that we can touch objects and the ‘projection’ is ‘real’ from our perspective.
In recent decades, advances in telescopes and sensing equipment have allowed scientists to detect a vast amount of data hidden in the ‘white noise’ or microwaves (partly responsible for the random black and white dots you see on an un-tuned TV) left over from the moment the universe was created. Using this information, the team was able to make complex comparisons between networks of features in the data and quantum field theory. They found that some of the simplest quantum field theories could explain nearly all of the cosmological observations of the early universe.
Professor Skenderis comments: “Holography is a huge leap forward in the way we think about the structure and creation of the universe. Einstein’s theory of general relativity explains almost everything large scale in the universe very well, but starts to unravel when examining its origins and mechanisms at quantum level. Scientists have been working for decades to combine Einstein’s theory of gravity and quantum theory. Some believe the concept of a holographic universe has the potential to reconcile the two. I hope our research takes us another step towards this.”
Scientists Unveil New Form of Matter: Time Crystals
To most people, crystals mean diamond bling, semiprecious gems, or perhaps the jagged amethyst or quartz crystals beloved by collectors.
To Norman Yao, these inert crystals are the tip of the iceberg.
If crystals have an atomic structure that repeats in space, like the carbon lattice of a diamond, why can’t crystals also have a structure that repeats in time? That is, a time crystal?
In a paper published online last week in the journal Physical Review Letters, the UC Berkeley assistant professor of physics describes exactly how to make and measure the properties of such a crystal, and even predicts what the various phases surrounding the time crystal should be—akin to the liquid and gas phases of ice.
This is not mere speculation. Two groups followed Yao’s blueprint and have already created the first-ever time crystals. The groups at the University of Maryland and Harvard University reported their successes, using two totally different setups, in papers posted online last year and have submitted the results for publication. Yao is a co-author on both papers.
“Time crystals repeat in time because they are kicked periodically, sort of like tapping Jell-O repeatedly to get it to jiggle,” Yao said. The big breakthrough, he argues, is less that these particular crystals repeat in time than that they are the first of a large class of new materials that are intrinsically out of equilibrium, unable to settle down to the motionless equilibrium of, for example, a diamond or ruby.
“This is a new phase of matter, period, but it is also really cool because it is one of the first examples of non-equilibrium matter,” Yao said. “For the last half-century, we have been exploring equilibrium matter, like metals and insulators. We are just now starting to explore a whole new landscape of non-equilibrium matter.”
While Yao is hard put to imagine a use for a time crystal, other proposed phases of non-equilibrium matter theoretically hold promise as nearly perfect memories and may be useful in quantum computers.
The time crystal created by Chris Monroe and his colleagues at the University of Maryland employs a conga line of 10 ytterbium ions whose electron spins interact, similar to the qubit systems being tested as quantum computers. To keep the ions out of equilibrium, the researchers alternately hit them with one laser to create an effective magnetic field and a second laser to partially flip the spins of the atoms, repeating the sequence many times. Because the spins interacted, the atoms settled into a stable, repetitive pattern of spin flipping that defines a crystal.
Time crystals were first proposed in 2012 by Nobel laureate Frank Wilczek, and last year theoretical physicists at Princeton University and UC Santa Barbara’s Station Q independently proved that such a crystal could be made. According to Yao, the UC Berkeley group was “the bridge between the theoretical idea and the experimental implementation.”
“From the perspective of quantum mechanics, electrons can form crystals that do not match the underlying spatial translation symmetry of the orderly, three-dimensional array of atoms,” Yao said. “This breaks the symmetry of the material and leads to unique and stable properties we define as a crystal.”
A time crystal breaks time symmetry. In this particular case, the magnetic field and laser periodically driving the ytterbium atoms produce a repetition in the system at twice the period of the drivers, something that would not occur in a normal system.
“Wouldn’t it be super weird if you jiggled the Jell-O and found that somehow it responded at a different period?” Yao said. “But that is the essence of the time crystal. You have some periodic driver that has a period ‘T’, but the system somehow synchronizes so that you observe the system oscillating with a period that is larger than ‘T’.”
Yao worked closely with Monroe as his Maryland team in making the new material, helping them focus on the important properties to measure in order to confirm that the material was in fact a stable, or rigid, time crystal. Yao also described how the time crystal would change phase, like an ice cube melting, under different magnetic fields and laser pulsing.
The Harvard team, led by Mikhail Lukin, set up its time crystal using densely packed nitrogen vacancy centers in diamonds.
“Such similar results achieved in two wildly disparate systems underscore that time crystals are a broad new phase of matter, not simply a curiosity relegated to small or narrowly specific systems,” wrote Phil Richerme, of Indiana University, in a perspective piece accompanying the paper published in Physical Review Letters. “Observation of the discrete time crystal… confirms that symmetry breaking can occur in essentially all natural realms and clears the way to several new avenues of research.”
Sound Waves Create Whirlpools to Round Up Tiny Signs of Disease
New technique could form the basis of a small, inexpensive point-of-care device for early disease diagnosis.
Mechanical engineers at Duke University have demonstrated a tiny whirlpool that can concentrate nanoparticles using nothing but sound. The innovation could gather proteins and other biological structures from blood, urine, or saliva samples for future diagnostic devices.
Early diagnosis is key to successfully treating many diseases, but spotting early indicators of a problem is often challenging. To pick out the first warning signs, physicians usually must concentrate scarce proteins, antibodies or other biomarkers from small samples of a patient’s body fluid to provide enough of a signal for detection.
While there are many ways to accomplish this today, most are expensive, time consuming or too cumbersome to take to the field, and they might require trained experts. Duke engineers are moving to develop a new device that addresses these obstacles.
The results appeared online January 25, 2017, in the journal American Chemical Society Nano.
By Ken Kingery: http://pratt.duke.edu/about/news/acoustic-whirlpools