Physics News of the Week: Dark Future of the Universe

| November 2, 2014 | 0 Comments

It’s another beautiful Sunday and it’s time to take a look at what’s been going on in the world of physics this week. Here are the top 3 news stories with additional links. If you would like to receive these news to your email box, register for our email newsletter.

1. Can the Wave Function of an Electron be Divided and Trapped? (Oct 28)

New research by physicists from Brown University puts the profound strangeness of quantum mechanics to test. Experiments led by Humphrey Maris, professor of physics at Brown, suggest that the quantum state of an electron can be shattered into pieces and those pieces can be trapped in tiny bubbles of liquid helium. This is achieved by a special canister of liquid helium, which allows scientists to experiment with tiny electron bubbles only 3.6 nanometers in diameter. If Maris’ interpretation of the experimental results is correct, it raises important questions regarding the measurement process in quantum mechanics.

“We are trapping the chance of finding the electron, not pieces of the electron,” Maris said. “It’s a little like a lottery. When lottery tickets are sold, everyone who buys a ticket gets a piece of paper. So all these people are holding a chance and you can consider that the chances are spread all over the place. But there is only one prize—one electron.”

“The experiments we have performed indicate that the mere interaction of an electron with some larger physical system, such as a bath of liquid helium, does not constitute a measurement,” Maris said. “The question then is: What does?”

The fate of the universe might be ‘darker’ than expected

2. Universe May Face a Darker Future (Oct 31)

Researchers in Portsmouth and Rome have recently discovered hints that dark matter is being slowly erased, swallowed up by dark energy. The findings appearing in the journal Physical Review Letters favours a model of dark energy that grows as it interacts with dark matter, which in turn appears to be slowing the growth of structure in the cosmos.

“Dark matter provides a framework for structures to grow in the Universe. The galaxies we see are built on that scaffolding and what we are seeing here, in these findings, suggests that dark matter is evaporating, slowing that growth of structure,” said Professor David Wands, Director of Portsmouth’s Institute of Cosmology and Gravitation. “If the dark energy is growing and dark matter is evaporating we will end up with a big, empty, boring Universe with almost nothing in it.”

3. Ultracold Dissapearing Act (Nov 2)

Rice University Physicist Randy Hulet and colleagues have recently observed a strange disappearing act during collisions between forms of Bose Einstein condensates called solitons.  The colliding clumps of matter appeared to keep their distance even as they passed through each other.

Pairs of Bose Einstein Condensates are clumps of a few hundred thousand lithium atoms that are cooled to within one-millionth of a degree above absolute zero, a temperature so cold that the atoms march in lockstep and act as a single “matter wave.” Solitons are waves that do not diminish, flatten out or change shape as they move through space. The researchers expected to observe the property that a pair of colliding solitons would pass though one another without slowing down or changing shape. However, they found that in certain collisions, the solitons approached one another, maintained a minimum gap between themselves, and then appeared to bounce away from the collision.

“You never see them together,” said Hulet, Rice’s Fayez Sarofim Professor of Physics and Astronomy. “There is always a hole, a gap that they must jump over. They pass through one another, but they never occupy the same space while they’re doing that.” The phenomena is most likely best explained by the wave packet interference. “Think of them as waves that can have a positive or negative amplitude,” explained Hulet. “One of the solitons is positive and the other is negative, so they cancel one another. The probability of them being in the spot where they meet is zero. They pass through that spot, but you never see them there.”

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