I see that Stephen Hawking has a new book under contract. The Grand Design is to be co-authored by Leonard Mlodinow, who also worked with Hawking on A Briefer History of Time. This one takes on an issue that is challenging even for Hawking, namely the question of why the laws of physics act as they do and, if a Bantam Dell publisher is to be believed, the question of why there is a universe in the first place.
Meanwhile, Hawking spent the week of September 24 to October 1 visiting CERN in Geneva, meeting with physicists in the Theory Unit of the Physics Department there and touring the facilities of the Large Hadron Collider, due to be started up in 2007. Note that two Hawking lectures are now available over the Web, one of which, titled The Origin of the Universe, anticipates the new book. The other, The Semi-Classical Birth of the Universe, is aimed at a specialist audience.
And one other note apropos of great physicists for an otherwise quiet weekend. The BBC offers a 1981 interview with Richard Feynman here.
great stuff.
The No-Boundary Measure of the Universe
Authors: James B. Hartle, S.W. Hawking, Thomas Hertog
(Submitted on 29 Nov 2007 (v1), last revised 6 Feb 2008 (this version, v3))
Abstract: We consider the no-boundary proposal for homogeneous isotropic closed universes with a cosmological constant and a scalar field with a quadratic potential. In the semi-classical limit, it predicts classical behavior at late times if the initial scalar field is more than a certain minimum. If the classical late time histories are extended back, they may be singular or bounce at a finite radius. The no-boundary proposal provides a probability measure on the classical solutions which selects inflationary histories but is heavily biased towards small amounts of inflation. This would not be compatible with observations. However we argue that the probability for a homogeneous universe should be multiplied by exp(3N) where N is the number of e-foldings of slow roll inflation to obtain the probability for what we observe in our past light cone. This volume weighting is similar to that in eternal inflation but derived in a gauge invariant manner and without redundant bubble universes outside our past light cone. In a landscape potential, it would predict that the universe would have a large amount of inflation and that it would start in an approximately de Sitter state near a saddle-point of the potential. The universe would then have always been in the semi-classical regime.
Comments: 4 pages, revtex4, one argument improved
Subjects: High Energy Physics – Theory (hep-th); Astrophysics (astro-ph); General Relativity and Quantum Cosmology (gr-qc)
Cite as: arXiv:0711.4630v3 [hep-th]
Submission history
From: James B. Hartle [view email]
[v1] Thu, 29 Nov 2007 00:29:59 GMT (165kb)
[v2] Thu, 13 Dec 2007 23:54:27 GMT (165kb)
[v3] Wed, 6 Feb 2008 22:23:45 GMT (165kb)
http://arxiv.org/abs/0711.4630
QED – a play about Richard Feynman
Henri Szeps plays Richard Feynman in Peter Parnell’s play
about physicist Richard Feynman. Henri Szeps discusses his
character and we hear some archival material of Feynman.
Full transcript here:
http://www.abc.net.au/rn/scienceshow/stories/2008/2234039.htm
Microsoft CEO Bill Gates recently took a trip to CERN with his ten year old son who
has a strong interest in physics and announced that Richard Feynman’s Messenger
Lecturers from the 1960s will soon be made by him available for free to all – as all
education and knowledge should be (or at least everyone should have an equal
opportuntity to learn).
The quote by Gates from the following article:
“We need more kids doing maths and physics – it’s good for them and it’s good for the peaceful innovation of the world,” he said. But in Gates’ opinion part of the problem is the way science is taught. “Even some very bright people can find science intimidating and uninteresting. But it can be explained well,” he continued.
“I just bought the rights to the Feynman ‘Messenger Lectures’ that he gave in Cornell [University] in the 1960s. The BBC filmed Feynman giving what I think are the best physics lectures I have ever seen. So we are going to make these lectures free for anyone to watch.”
The CERN Bulletin article URL:
http://cdsweb.cern.ch/journal/article?issue=26/2009&name=CERNBulletin&category=News%20Articles&number=6&ln=en
Hawking says there were an infinite number of quantum beginnings:
http://www.dailygalaxy.com/my_weblog/2009/10/were-there-an-infinite-number-of-quantum-beginnings-stephen-hawking-says-yes.html