Archive for February 2015

The Search For Neutrons That Leak Into Our World From Other Universes

The Search For Neutrons That Leak Into Our World From Other Universes — The Physics arXiv Blog — Medium

One of the more exciting ideas in high energy physics is the possibility that our three-dimensional universe is embedded in a much bigger multidimensional cosmos. Physicists call these embedded universes “branes” and say that it should be possible for stuff from our brane to leak into other branes nearby and vice versa.

Today, Michael Sarrazin at the University of Namur in Belgium and a few pals say they have worked out to detect this leakage by measuring whether neutrons can bypass barriers by leaping into another brane and back again.

These guys are proposing to measure this effect by placing a neutron detector close to a nuclear reactor to see whether neutrons appear unexpectedly as a result of being transported out of the reactor via another braneworld.

via The Search For Neutrons That Leak Into Our World From Other Universes — The Physics arXiv Blog — Medium.

Google Brain’s Co-Inventor Tells Why He’s Building Chinese Neural Networks

To chat with Andrew Ng I almost have to tackle him. He was getting off stage at Re:Work’s Deep Learning Summit in San Francisco when a mob of adoring computer scientists descended on (clears throat) the Stanford deep learning professor, former “Google Brain” leader, Coursera founder and now chief scientist at Chinese web giant Baidu.

[snipped]

Um, can you elaborate on studying time?

By moving your head, you see objects in parallax. (The idea being that you’re viewing the relationship between objects over time.) Some move in the foreground, some move in the background. We have no idea: Do children learn to segment out objects, learn to recognize distances between objects because of parallax? I have no idea. I don’t think anyone does.

There have been ideas dancing around some of the properties of video that feel fundamental but there just hasn’t yet been that result. My belief is that none of us have come up with the right idea yet, the right way to think about time.

Animals see a video of the world. If an animal were only to see still images, how would its vision develop? Neuroscientists have run experiments in cats in a dark environment with a strobe so it can only see still images—and those cats’ visual systems actually underdevelop. So motion is important, but what is the algorithm? And how does [a visual system] take advantage of that?

I think time is super important but none of us have figured out the right algorithms for exploring it.

[That was all we had time for at the Deep Learning Summit. But I did get to ask Ng a followup via email.]

Do you see AI as a potential threat?

I’m optimistic about the potential of AI to make lives better for hundreds of millions of people. I wouldn’t work on it if I didn’t fundamentally believe that to be true. Imagine if we can just talk to our computers and have it understand “please schedule a meeting with Bob for next week.” Or if each child could have a personalized tutor. Or if self-driving cars could save all of us hours of driving.

I think the fears about “evil killer robots” are overblown. There’s a big difference between intelligence and sentience. Our software is becoming more intelligent, but that does not imply it is about to become sentient.

The biggest problem that technology has posed for centuries is the challenge to labor. For example, there are 3.5 million truck drivers in the US, whose jobs may be affected if we ever manage to develop self-driving cars. I think we need government and business leaders to have a serious conversation about that, and think the hype about “evil killer robots” is an unnecessary distraction.

Read full interview via Google Brain’s Co-Inventor Tells Why He’s Building Chinese Neural Networks — Backchannel — Medium.

Cosmic inflation theory of Big Bang bites the space dust

Cosmic inflation theory of Big Bang bites the space dust | MNN - Mother Nature Network

It is the announcement no one wanted to hear: The most exciting astronomical discovery of 2014 has vanished. Two groups of scientists announced on Jan. 30 that a tantalizing signal — which some scientists claimed was “smoking gun” evidence of dramatic cosmic expansion just after the birth of the universe — was actually caused by something much more mundane: interstellar dust.

In the cosmic inflation announcement, which was unveiled in March 2014, scientists with the BICEP2 experiment, claimed to have found patterns in light left over from the Big Bang that indicated that space had rapidly inflated at the beginning of the universe, about 13.8 billion years ago. The discovery also supposedly confirmed the existence of gravitational waves, theoretical ripples in space-time.

But in a statement, scientists with the European Space Agency said that data from the agency’s Planck space observatory has revealed that interstellar dust caused more than half of the signal detected by the Antarctica-based BICEP2 experiment. The Planck spacecraft observations were not yet available last March when the BICEP2 science team made its announcement. [Cosmic Inflation and the Big Bang Explained (Infographic)]

“Unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation,” Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d’Astrophysique Spatiale in Orsay, France, said in the statement. The conclusion is the result of a collaborative analysis by scientists with both BICEP2 and Planck, using data from both telescopes as well as the Keck array at the South Pole.

via Cosmic inflation theory of Big Bang bites the space dust | MNN – Mother Nature Network.