Hartle Definition and 15 Threads

Physicists Stephen W Hawking and James B Hartle 1 proposed that the universe, in its origins, had no boundary conditions both in space and time. To do that, they proposed a sum over all compact euclidean compact metrics. I have heard that they only considered these metrics in order to simplify...

A question concerning FIg. 7.11 on page 173. It seems to me, in light of what is said on the preceding page about null surfaces, that he has interchanged "normal" and "tangent" in the third and fourth sentences of the figure caption. I would say: "The tangent to the surface l lies in the...

Hi guys! I am reading the book "Gravity" by Hartle. I came across this scary-looking integral. The author does integration by parts and I don't get how he does it. Could someone guide me please? Relevant equations: ∫u dv = uv - ∫v du

I've started learning GR from Hartle's "Gravity: An Introduction ...". It's all going well, but I feel I could benefit from solutions to some of the key problems. I assume Hartle hasn't published a companion solution guide. A few options show up on line. One by Jorge Ramos, for example. Any...

Here was my success with trying to understand Hartle. Thanks WannabeNewton. https://www.youtube.com/watch?v=Fvt-Fc6uQjc

It started out OK, like a lot of books, but all of a sudden I hit a mass of integrals at page 22 out of nowhere. No build up, no explanation, many solution steps skipped (of course). Sorry to sound weak, but I need to be "nannied" through the maths of General relativity. I'm a right brain...

I came across this statement from James Hartle on Stephen Hawking's website, http://www.hawking.org.uk/ and wondered where you see this proposal currrently [Hartle sure seems to think it explains an awful lot] : James Hartle: Wikipedia has a brief discussion here...

I'm going to attempt to start a beginner GR book since we're covering it in Modern Physics and I've been covering the material up a notch so far (I did the SR by reading Spacetime Physics by Taylor and Wheeler & I've already read Griffith's for the Qmech section etc.) I don't intend to finish an...

In Fredrik's recent thread: https://www.physicsforums.com/showthread.php?t=506326 some questions arose about this paper: J. B. Hartle, "Quantum Mechanics of Individual Systems", Am. J. Phys., vol 36, no 8, (1968), pp704-712. [For other readers, you'll need to have read or be able to...

Hartle Hawking suggest probabilities for observations (eternal inflation picture) http://arxiv.org/abs/1009.2525 Eternal inflation without metaphysics James Hartle, S.W. Hawking, Thomas Hertog 4 pages (Submitted on 13 Sep 2010) "In the usual account of eternal inflation the universe is...

I hope this is the right forum to post this... I'm going through Wald's book in my first graduate level GR course, and am looking for lower level supplementary reading. I have a relatively strong math background, so Wald's language suits me well, but sometimes I feel like I need more...

Helo all, I have a very simple question about basis Four-Vectors and Components. In Hartle's book, Gravity, he uses the following equation to show the components of the 4-vector, a a =a^t{}e(sub t) + a^x{}e(sub x) + a^y{}e(sub y) + a^z{}e(sub z) Sorry for the half LaTex half something...

I am looking for a study partner (over the internet) I am using Gravity by James B. Hartle. Is there anyone else using this book that would like to study with me. Also, I am teaching myself. Thanks

Help with Hartle! Hello, I find Hartle's working very confusing. I was wondering if someone could help me decode this problem: Three observers are standing near each other on the surface of the Earth. Each holds an accurate atomic clock. At time t = 0 the first observer throws their clock...

I just watched this talk by Hartle Generalizing Quantum Mechanics for Quantum Spacetime given at Perimeter on 19 April, just a couple of days ago. http://streamer.perimeterinstitute.ca:81/mediasite/viewer/FrontEnd/Front.aspx?&shouldResize=False in the seminar series near the top of the list...