# Modeling a Universe

1. Feb 14, 2008

### Dennis Sugden

Several years ago, after reading about Wheeler's quantum foam, I wondered what would happen if you used wormhole propogation and a quality in some wormhole positions to prefer taking the shortest distance to the next position (mass) to try to reproduce effects similar to gravity. I had also just read about gravity "corridors" used by NASA and I wanted to see what they were like.

I programed my computer to start at three (mass) positions; one a factor of 100, one of 10, and one of 1. [this is all 2D] As I wasn't concerned to exactly match gravity an arbitrary length was established as the unconstrained wormhole length. I don't remember exactly what it was. I remember I chose it to make it easier to shade colors on my screen display. Then at each mass position and at each point on the screen going in circles around the (masses) a value of that wormhole length was calculated. eg at point (mass 1) length = Arbitrary/2; point (mass 1-1) = Arbitrary/2; point (mass1-2) = Arbitrary /4; etc.

When all points had been calculated each mass randomly moved to the new calculated level but preferred a new position that involved the shortest length.

On the computer I had then this ran forever but as I was shading screen colors to show short to long points I could watch it slowly change.

Point is I got curvatures that bent hypothetical light rays and even frame dragging. And I got to look at my gravity corridors.

Marcus, does this in any way connect to the models some of your posts refer to?

2. Feb 14, 2008

### marcus

Dennis, what you programmed sounds like a visually intriguing process to watch. I can't tell how or if it relates to the computerized universe models I've been reading about lately. That would be something for you to decide.

The models I am most interested in are of two kinds. one type is what they run at Utrecht Institute of Theoretical Physics---a lead author is named Renate Loll

the other is a kind of model they run at Penn State, particularly Ashtekar's group and also Bojowald.

The field is a relatively new one called Quantum Cosmology and it is sort of on the borderline between QG (in the Beyond forum) and Cosmology (in the Cosmology forum).
The current research can, i guess, be discussed in either place.

Have a look at the literature just to see what I'm talking about. Don't get bogged down in heavy details, just take a glance.

Here are Loll's papers
http://arxiv.org/find/grp_physics/1/au:+Loll/0/1/0/all/0/1
The one titled "Quantum Gravity on Your Desktop" describes some of the computer simulations of quantum universes

Here are recent (keyword=quantum cosmology) papers in the Stanford database, sorted by number of citations. the most highly cited papers appear first
http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=k+quantum+cosmology+and+date+%3E+2005&FORMAT=WWW&SEQUENCE=citecount%28d%29 [Broken]

If this kind of overview doesnt work for you, ask for links to some sample papers. But instead of delving into entire papers you can tell a little bit of what is going on by just looking at the titles and reading the abstracts (brief summaries).

It seems as if you made something beautiful on the computer that was inspired by Wheeler's conception of quantum foam, but it might be difficult to find a connection at the nutsbolts level.

Last edited by a moderator: May 3, 2017