quantum dynamics

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An Interesting video explaining various fields of Physics.

The Question That Could Unite Quantum Theory With General Relativity: Is Spacetime Countable?

Current thinking about quantum gravity assumes that spacetime exists in countable lumps, like grains of sand. That can’t be right, can it?

One of the big problems with quantum gravity is that it generates infinities that have no physical meaning. These come about because quantum mechanics implies that accurate measurements of the universe on the tiniest scales require high-energy. But when the scale becomes very small, the energy density associated with a measurement is so great that it should lead to the formation of a black hole, which would paradoxically ruin the measurement that created it.

These kinds of infinities are something of an annoyance. Their paradoxical nature makes them hard to deal with mathematically and difficult to reconcile with our knowledge of the universe, which as far as we can tell, avoids this kind of paradoxical behaviour.

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How we escaped the Big Bang: New theory on moving through time

Associate Professor Dr Joan Vaccaro, of Griffith’s Centre for Quantum Dynamics, has solved an anomaly of conventional physics and shown that a mysterious effect called ’T violation’ could be the origin of time evolution and conservation laws.

“I begin by breaking the rules of physics, which is rather bold I have to admit, but I wanted to understand time better and conventional physics can’t do that,” Dr Vaccaro says.

“I do get conventional physics in the end though. This means that the rules I break are not fundamental. It also means that I can see why the universe has those rules. And I can also see why the universe advances in time.”

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Meet the Blogger

Hello, fellow science lovers!

I’ve had quite a few new followers since the last time I formally introduced myself, so I thought I’d take a few moments to do just that!

I’m Devon, the blogger and scientist behind Scientists are People Too. Currently, I’m a fourth year graduate student at UCLA working on a PhD in physical chemistry. For three years, I did ultrafast spectroscopy to look at the condensed phase dynamics of simple molecules (and bashing my head against what turned out to be a dead-end project -_-).

However, this past summer, my wonderful husband and I found out that I was going to have a baby! Since my ultrafast work involved some pretty nasty chemicals, my PI helped me switch over to a theory project. I’ve thus spent the past few months working on mixed quantum/classical molecular dynamics simulations and preparing for parenthood!

I’ve been less active on here recently due to the holidays plus the fact that I’m due to give birth any day now, but I’ve got lots of great science blogging planned for the near future!

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Can LIGO test quantum gravity?

“The dynamics of a black hole merger and the way gravitational waves travel is sensitive to even smallest deviations from general relativity, like for example violations of the equivalence principle or the possibility that the graviton is not exactly massless. Bimetric gravity, higher-order modifications of general relativity, additional long-range interactions, or the gravitational aether – all these models will have to pass additional tests now. Undoubtedly, some will be winners (most likely where the disagreements from relativity’s predictions are too small to rule out), and some will be losers. And maybe one of them will turn out to supersede Einstein’s masterwork.”

General relativity makes very specific prediction for what the curvature of space should be at the event horizon of a black hole, and for the consequences to spacetime are for a mass accelerating outside, near and through it. However, a fully quantum theory of gravity is needed to understand what happens at or near a black hole’s singularity. In some variations of quantum gravity, though, there are departures from Einstein’s theory that will extend farther out than the singularity itself, and these variations may be testable by LIGO. As more events come in, we can look for deviations from general relativity’s predictions, and if we find them, perhaps we’ll uncover the first evidence for gravitational physics beyond the scope of Einstein’s relativity after all.