Ben Shoemate's Notebook

Breaking radio silence here to report on some of the actual work I’ve been able to complete: a new paper with Heywood Tam.

Unitary Evolution and Cosmological Fine-Tuning
Authors: Sean M. Carroll, Heywood Tam
(Submitted on 8 Jul 2010)

Abstract: Inflationary cosmology attempts to provide a natural explanation for the flatness and homogeneity of the observable universe. In the context of reversible (unitary) evolution, this goal is difficult to satisfy, as Liouville’s theorem implies that no dynamical process can evolve a large number of initial states into a small number of final states. We use the invariant measure on solutions to Einstein’s equation to quantify the problems of cosmological fine-tuning. The most natural interpretation of the measure is the flatness problem does not exist; almost all Robertson-Walker cosmologies are spatially flat. The homogeneity of the early universe, however, does represent a substantial fine-tuning; the horizon problem is real. When perturbations are taken into account, inflation only occurs in a negligibly small fraction of cosmological histories, less than 10^{-6.6×10^7}. We argue that while inflation does not affect the number of initial conditions that evolve into a late universe like our own, it nevertheless provides an appealing target for true theories of initial conditions, by allowing for small patches of space with sub-Planckian curvature to grow into reasonable universes.

In English: our universe looks very unusual. You might think we have nothing to compare it to, but that’s not quite right; given the particles that make up the universe (or the quantum degrees of freedom, to be technical about it), we can compare their actual configuration to all the possible configurations they could have been in. The answer is, our observed universe is highly non-generic, and in the past it was even more non-generic, or “finely tuned.” One way of describing this state of affairs is to say that the early universe had a very low entropy. We don’t know why; that’s an important puzzle, worth writing books about.

Part of the motivation of this paper was to put some quantitative meat on some ideas I discussed in my book. The basic argument is an old one, going back to Roger Penrose in the late 1970’s. The advent of inflation in the early 1980’s seemed to change things — it showed how to get a universe just like ours starting from a tiny region of space dominated by “false vacuum energy.” But a more careful analysis shows that inflation doesn’t really change the underlying problem — sure, you can get our universe if you start in the right state, but that state is even more finely-tuned than the conventional Big Bang beginning.

We revisit this question, bringing to bear some mathematical heavy machinery developed in the 1980’s by Gary Gibbons, Stephen Hawking, and John Stewart. Previous discussions have invoked general ideas of entropy or reversibility, but we were able to do a relatively down-to-earth calculation using conventional cosmological models. And we tried our best to explicitly list all of the caveats of the argument, which is important in a context like this where we don’t know all the rules.

We find that inflation is very unlikely, in the sense that a negligibly small fraction of possible universes experience a period of inflation. On the other hand, our universe is unlikely, by exactly the same criterion. So the observable universe didn’t “just happen”; it is either picked out by some general principle, perhaps something to do with the wave function of the universe, or it’s generated dynamically by some process within a larger multiverse. And inflation might end up playing a crucial role in the story. We don’t know yet, but it’s important to lay out the options to help us find our way.

via http://27.media.tumblr.com/tumblr_kp49f3GTet1qzxdxzo1_400.jpg

by Lance Rosenfield, Special to ProPublica

Freelance photographer Lance Rosenfield was working on assignment for ProPublica in Texas City, Texas, last week, when a BP security guard began following him. Rosenfield was later detained by police after taking photos for two ProPublica stories. One revealed that BP’s Texas City refinery had illegally emitted 538,000 pounds of toxic chemicals into the air in April and May. The other reported that the Texas City refinery continues to have serious safety violations five years after an explosion at the plant killed 15 workers.

What follows is Rosenfield’s account of what happened on Friday night after the police, accompanied by the BP security guard, stopped him at a local gas station.

I parked my car on the shoulder of Hwy. 197 near the Texas City sign that is in the pictures, on the south side of town and the refinery. I walked onto the median where the sign is and took the pictures. I walked back to my car and drove a couple of miles to a gas station that is on the way to my hotel. I noticed that what looked like a security truck, which had a light on the top, was following me, although he continued on when I pulled into the Valero gas station. I got out of my car to fill the tank and moments later two Texas City police cars pulled in next to my car, essentially blocking me in, although I wasn't trying to go anywhere, I was trying to get gas.

The first police officer asked me what I was doing and said he had gotten a report that I was taking pictures near the refinery. I told him I am a photojournalist and had only taken some pictures of a Texas City sign. He asked to see the pictures and I told him I didn't think I had to show them, legally. Another police officer walked up and again asked to see the pictures. I told him the same thing, but assured him that they were just pictures of the city sign, taken while I was in the public right of way.

He said I could show him the pictures or he could handle this another way, including calling Homeland Security and taking me in. I agreed to show him the pictures on the back of my camera, while he took my driver's license. Meanwhile, the truck that had been following me showed up, driven by a security guard with a BP patch on his uniform. The first police officer seemed to fade back during all this, but remained present in the background. I asked the second police officer-- Officer T. Krietemeyer--for his card, which he gave me. 

Officer Krietemeyer took my name, driver's license, the car license number, my D.O.B., Social Security Number and phone number.

The BP security guard asked for my personal information and I declined because he is a corporate security guard and I had already given it to the police. Then the BP security guard asked Officer Krietemeyer for my information, which he gave him.

I protested and asked on what legal grounds could the police officer share my information with BP? I was never on BP property. They told me it was standard procedure and I told them I didn't agree with it and didn't understand what legal authority they had to share that information.

They said that when there is a Homeland Security threat, then BP files a report. I said I wasn't a Homeland Security threat, that Officer Krietemeyer had already determined that the pictures posed no threat. Also, I was not under arrest, so why was BP getting my information? I asked the BP guard for his information, which he gave me: Gary Stief, BP Security.

They both told me they would call Homeland Security/FBI agent Tom Robison to come down and explain it, as if that were a threat to me. I said I didn't think that was necessary but Officer Krietemeyer called Mr. Robison anyway and handed me the phone, which I didn't ask for, but my natural reaction was to take the phone. They had already spoken to Mr. Robison when they arrived; when he got on the phone he asked what my problem is. I told him I didn't understand why BP was getting my information, but he had it anyway and we were starting to wrap up here. He said, "Oh no you're not, you're staying right there until I get there." This was obviously a scare tactic.

Mr. Robison arrived several minutes later and asked what my problem was. His demeanor was aggressive and antagonistic. I repeated myself, in a respectful manner. He aggressively explained that a refinery like this is a terrorist target and any time people take pictures of it, they have to investigate.

He asked who I was working for. I said I'm a freelance photojournalist working on assignment for ProPublica. He asked for verification of that so I showed him the letter from (ProPublica senior editor) Susan White. Officer Krietemeyer took down the information. Mr. Robison tried to dig at what the article was about, and I stayed mostly vague because I'm not the writer and I didn't see the significance anyway. Eventually he asked if it's about BP and I said yes, which seemed to make him angrier.

I then felt like Mr. Robison and Mr. Stief, the BP guard, started harassing me, primarily by keeping me there and talking to me in an aggressive and antagonistic manner, and relating what I had done to terrorist activity, ignoring what had actually happened. This went on for some time. I stayed calm and polite and on point.

Mr. Robison twice asked Officer Krietemeyer if had he reviewed the pictures carefully and concluded there was no threat, to which Officer Krietemeyer said yes. Mr. Robison seemed to be shaky with adrenaline; he was clearly worked up.

Stief said he was ready to go so the group broke up quickly.

I shook all three men's hands.

I'm guessing the whole thing lasted 20 to 30 minutes.