#### marcus

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Really should call it "Big Bounce" instead of Big Bang.

Yesterday another paper was posted at the Los Alamos arxiv

about getting rid of the Big Bang glitch by quantizing General Relativity.

Martin Bojowald started this line of research but more people are getting into it, the new paper is by a guy at Hamilton College and someone in the Czech Republic

http://arxiv.org/abs/gr-qc/0309035

"Isotropic Loop Quantum Cosmology with Matter II: the Lorentzian Constraint"

Franz Hinterleitner (Masaryk University, Brno) and Seth Major (Hamilton College)

The essential thing here is that (by failing at certain points) classical theories sometimes predict their own replacement by quantized versions. GR does this by breaking down at the time zero singularity (BB) and failing to compute.

There are historical parallels-----in 1900 Planck came up with a theory of thermal radiation (the first quantum theory of anything) that cured a "singularity" in the classical theory of how hot objects radiate-----the classical unquantized theory suffered from infinities, failing to compute sensible answers at either very short or very long wavelengths. Not too long after that Bohr came up with a quantum theory of the hydrogen atom which cured another classical glitch---the unquantized theory predicted absurd results at a certain point and he fixed the bug.

Sometimes by having glitches, a classical theory will show it needs to be quantized, and quantizing it sometimes fixes the bugs. The Big Bang is a glitch in GR. Quantizing GR in a minimal way (not adding new structure besides what is necessary to quantize the basic equations of GR) gets rid of the trouble at time zero (and also predicts inflation without having to add any new particle or field, just from a quantum geometrical effect of ordinary matter)

So there are a bunch of papers cropping up about this and more people getting into it. Here are some names in no particular order of people who (since Bojowald started it) have published about loop quantum cosmology getting rid of the big bang singularity and/or deriving inflation as a result of loop-quantizing GR

Ashtekar

Lewandowski

Bojowald

Smolin

Stephon Alexander (SLAC)

Golam Hossain (Chennai, India)

Gambini

Pullin

Seth Major

Franz Hinterleitner

doubtless I've missed some

Hossain's paper was mainly about getting inflation

by loop-quantizing GR, but incidentally gets rid of BB singularity.

Yesterday another paper was posted at the Los Alamos arxiv

about getting rid of the Big Bang glitch by quantizing General Relativity.

Martin Bojowald started this line of research but more people are getting into it, the new paper is by a guy at Hamilton College and someone in the Czech Republic

http://arxiv.org/abs/gr-qc/0309035

"Isotropic Loop Quantum Cosmology with Matter II: the Lorentzian Constraint"

Franz Hinterleitner (Masaryk University, Brno) and Seth Major (Hamilton College)

The essential thing here is that (by failing at certain points) classical theories sometimes predict their own replacement by quantized versions. GR does this by breaking down at the time zero singularity (BB) and failing to compute.

There are historical parallels-----in 1900 Planck came up with a theory of thermal radiation (the first quantum theory of anything) that cured a "singularity" in the classical theory of how hot objects radiate-----the classical unquantized theory suffered from infinities, failing to compute sensible answers at either very short or very long wavelengths. Not too long after that Bohr came up with a quantum theory of the hydrogen atom which cured another classical glitch---the unquantized theory predicted absurd results at a certain point and he fixed the bug.

Sometimes by having glitches, a classical theory will show it needs to be quantized, and quantizing it sometimes fixes the bugs. The Big Bang is a glitch in GR. Quantizing GR in a minimal way (not adding new structure besides what is necessary to quantize the basic equations of GR) gets rid of the trouble at time zero (and also predicts inflation without having to add any new particle or field, just from a quantum geometrical effect of ordinary matter)

So there are a bunch of papers cropping up about this and more people getting into it. Here are some names in no particular order of people who (since Bojowald started it) have published about loop quantum cosmology getting rid of the big bang singularity and/or deriving inflation as a result of loop-quantizing GR

Ashtekar

Lewandowski

Bojowald

Smolin

Stephon Alexander (SLAC)

Golam Hossain (Chennai, India)

Gambini

Pullin

Seth Major

Franz Hinterleitner

doubtless I've missed some

Hossain's paper was mainly about getting inflation

by loop-quantizing GR, but incidentally gets rid of BB singularity.

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