We all know how it feels to be low on energy at the end of a long work day. Some call-center agents at insurer MetLife are watched over by software that knows how it sounds. Continue reading “This Call May Be Monitored for Tone and Emotio”
To Understand the Universe, Physicists Are Building Their Own
The Big Bang is by far the most popular model of our universe’s beginnings, but even its fans disagree about how it happened. The theory depends on the existence of a hypothetical quantum field that stretched the universe ultra-rapidly and uniformly in all directions, expanding it by a huge factor in a fraction of a second: a process dubbed inflation. But that inflation or the field responsible for it—the inflaton—is impossible to prove directly. Which is why Weinfurtner wants to mimic it in a lab.
If the Big Bang theory is right, the baby universe would have been created with tiny ripples—so-called ‘quantum fluctuations’—which got stretched during inflation and turned into matter and radiation, or light. These fluctuations are thought to have eventually magnified to cosmic size, seeding galaxies, stars, and planets. And it’s these tiny ripples that Weinfurtner wants to model with that massive superconducting magnet. Inside, she’ll put a circular tank, some 6 centimeters in diameter, filled with layered water and butanol (the liquids have different densities, so they don’t mix).
Then, her group of researchers will kick in the artificial gravity distortions. “The strength of the magnetic field varies with its position,” says Richard Hill, one of the paper’s co-authors. “By moving the pool to different regions of the field, the effective gravitational force can be increased or decreased,” he says, “and can even be turned upside-down.”
By varying gravity, the team hopes to create ripples—but unlike those on a pond, the distortions will appear between the two liquids. “By carefully adjusting the speed of the ripples we can model an inflating universe,” says another team member, Anastasios Avgoustidis. In cosmic inflation, space rapidly expands while the ripples of matter propagate at a constant speed—and in the experiment, the speed of the ripples rapidly decreases as the liquid’s volume remains constant. “The equations describing the propagation of ripples in these two scenarios are identical,” Avgoustidis says.
That’s important: If the resulting fluctuations look as if they might trigger structures like those found in today’s universe, then we may have had a glimpse of how inflation worked.
Simulations are being used to study other aspects of inflation, too. A few years ago, a team led by Christoph Westbrook of CNRS (The French National Center for Scientific Research) in Paris studied the production of quantum particles by ‘wiggling’ a ring Bose Einstein condensate—a state of matter in which the atoms have been cooled to near absolute zero, making them behave as a single quantum object. During inflation, the temperature of the universe dropped drastically, before starting to rise again when the inflation ceased with the process called ‘reheating’—leading to the ordinary Big Bang expansion.
Another experiment last October, led by physicist Stephen Eckel at the Joint Quantum Institute at the National Institute of Standards and Technology and University of Maryland, also used a Bose Einstein condensate to observe the stretching of sound waves—analogous to the stretching, or redshifting, of light that happens as the universe expands. The team also observed an effect similar to the reheating process.
Weinfurtner says that her ‘novel’ setup can work without a Bose Einstein condensate. That means that the system will be too hot to observe quantum fluctuations directly, says Unruh. But the authors argue that it will be possible to observe the fluctuations via the thermal noise in their system—an analog of quantum noise.
Their approach, say the authors, will allow them to mimic a long expansion phase, achieving—using the technical language—‘many e-folds,’ a parameter that measures the duration of inflation. Researchers believe that inflation increased the size of the universe by more than a factor of 10^26—or more than 60 e-folds—in just a fraction of a second. The new experiment, if successful, would simulate inflation for much longer period than previous lab set-ups, or have “many more e-folds than any other, enough to put the results beyond doubt,” says Ian Moss of the University of Newcastle. “You need some time to elapse for the system to forget its initial conditions and settle down to the state governed by inflationary fluctuations,” he says.
“It is possible that they will uncover new physics that help to inform future cosmological models,” says Eckel. “Or, on the reverse, help to test some aspect of future cosmological models.”
The real test of inflation would be, Loeb says, the production of the substance that propelled it—the inflaton—in the lab. But this would require reaching energies up to a trillion times larger than those achieved in our most powerful particle accelerator, the Large Hadron Collider—and such a test seems unlikely in the near future.
“Just mimicking the equations of an analogous system is a metaphor to the real system, not an actual test of its fundamental properties,” says Loeb. It’s like “smelling food instead of eating the actual food,” he adds, only “the latter has the real value.”
That’s true, but sometimes the smells from a kitchen can tell you a lot about what was served for dinner.
Galactic Investigators
- Dan Hooper and his colleagues found a glow coming from the center of our galaxy that no one had ever noticed before—and it could hold new information about the universe.
- For nearly a decade, Shami Chatterjee and other astrophysicists have been trying to understand the nature of fast bursts of radio waves in space.
- Rachael Livermore uses the Hubble Space Telescope to spot extremely faint galaxies from as far back as 600 million years after the Big Bang.
Continue reading “To Understand the Universe, Physicists Are Building Their Own”
Incredible UX Design Innovations for iOS
UX is one of the most important components of software design. Designing and developing software is about creating a usable software product. Usability is more important than functionality. We’ve seen examples of this time and time again. Continue reading “Incredible UX Design Innovations for iOS”
Closing the SEO/SEM Gap with… Alexa?
The competition among those engaged in search engine optimization and digital advertising campaigns has never been greater, but there are an abundance of very powerful tools available – some of which marketers may likely already be aware of – that can help them “close the gap.” Continue reading “Closing the SEO/SEM Gap with… Alexa?”