Thursday, May 31, 2007

Varying Speed of Light (VSL) theories: crackpots par excellence

The archives and sometimes even journals are continuously flooded with new articles about a theory that was originally invented by young Earth creationists to reconcile the Bible with the Big Bang and that was later adopted by non-Christian crackpots, too. It is called
  • Varying Speed of Light (VSL) theory
George Ellis has decided that there should exist an authoritative, published article explaining why all this VSL industry is complete crap. I fully agree. If this nonsense keeps on appearing all the time, there should exist some reactions that can be referred to. He mentions virtually identical arguments that I always say about these VSL theories:
  • Their authors don't understand that one can always change her units. They don't know what's the difference between dimensionless and dimensionful quantities.
  • The meter is moreover defined as 1/299,792,458 of a light second, so according to current definitions, a varying speed of light is simply a contradiction.
  • One doesn't gain anything whatsoever by redefining the speed of light in a time-dependent fashion because it is just a time-dependent change of units (or coordinates in GR).
  • When the speed of light is allowed to be different for various phenomena, we need to determine the right modifications in all equations of physics, including Maxwell's equations and others. No VSL paper is doing anything like that.
  • Moreover, one expects to end up with a generic non-relativistic theory with infinitely many parameters. The VSL papers never offer any principle that would replace the broken Lorentz symmetry and determine these parameters. They don't even acknowledge this problem.
In other words, VSL theories are 100% vacuous and stupid crap.

Tonight, Magueijo and Moffat have submitted an answer that have made me so upset by its breathtaking stupidity that I simply had to write this text to calm down. ;-) They don't understand a single one among Ellis' obvious complaints. Instead, they paint themselves as new Galileos because they are ready to make a constant variable.

Important physics has never worked like that. Quite on the contrary. Every new major revolution in physics has shown that a certain conversion parameter was not only constant but it was meaningful to set it equal to one.

Joule has figured out that heat and energy can be transformed to each other. We can thus use the same unit for both quantities: to celebrate his discovery, we call the international unit a Joule.

Einstein has found out that space and time are equivalent. This allowed him to declare "c" to be a universal constant. Moreover, all adult physicists who need relativistic phenomena use units where "c=1". This choice also implies that mass and energy are essentially the same thing.

Analogously, quantum physics is closely associated with Planck's constant. Frequencies are the same thing as energies. Adult physicists set "hbar=1". In quantum gravity we may also set Newton's constant "G=1" although in perturbative string theory, it is more natural to set "alpha'=1".

We no longer need degrees to measure angles because rads make equations simpler. Also, we don't need Avogadro's constants and moles because we can count individual atoms and molecules which are better "units" than moles. The number of constants we need to write into our equations decreases.

Making constants variable is going exactly in the opposite direction than what progress in theoretical physics has always been doing. The only "constants" that should be variable are those that depend on some parameters of the environment. But such a declaration of their variability is only interesting once we understand how the environment actually works. Saying that quantities should become variable without understanding how they vary is a meaningless sleight of hand but certainly not a complete theory of anything.

A very similar criticism applies, to a lesser extent, to doubly special relativity etc. The people who work on all these stupid things have a tremendous problem to distinguish physics from conventions, predictions from ways of writing things, deep insights from vacuous sequences of mathematical symbols. They don't understand what a choice of units and field redefinitions means and why they're unphysical. Despite all of their profound ignorance about basics of physics, these crackpots are extremely arrogant (Magueijo is the #1 example, of course) - they view themselves as competitors of inflationary cosmology and many other key segments of science - which makes me quite upset. ;-)

And that's the memo.

Weinberg cancels UK visit: cites anti-Semitism

Exactly one year ago, we reported that NATFHE, a bizarre left-wing organization, insists that the Jews must fight against their country if they don't want to be boycotted by a large part of the British academic world. That boycott was lifted so Weinberg agreed to attend a conference dedicated to Abdus Salam.

However, a week ago, Steven Weinberg sent a letter to Mike Duff that he couldn't visit the PASCOS conference because of anti-Semitism in Britain that was revived by another despicable boycott organized by a union of journalists - surely the same journalists as those who write that Einstein may have started the rot.

Weinberg mentions that he often sees anti-Semitism in the Guardian, the Independent, the BBC. But the previous link shows that the right-wing Telegraph may be added to the list, too.


That must be a doubly disappointing episode for Weinberg who loves Britain and who considers himself left-wing because these disgraceful campaigns are organized by British left-wing academics. Needless to say, similar events and sentiments are not confined to British schools. Similar campaigns at MIT and Harvard were anti-Semitic in effect, if not intent, too.

I just can't understand what leads the people to organize such campaigns against a country that surely belongs among the more democratic and decent ones and the most democratic and decent ones in the region. It must be a feeling that the Jews enjoy some advantages and wealth that they shouldn't enjoy. Maybe it is the $20,000 GDP per capita, exceeding all oil-rich Arab countries. Maybe it is the magic shekel. Maybe it is their right to have a country.

Whatever is the exact reason, we must ask: do the British scholars show a left-wing envy or a racist sentiment? Is there any way to distinguish between these two?

Hunt for the Higgs boson

Fullscreen. Via JoAnne Hewett.

Boss of NASA sensible on global warming

Michael Griffin who has been the top administrator of NASA since 2005 said the following on NPR (see news.google.com, transcript, blogs, audio):
I have no doubt that a trend of global warming exists. I am not sure that it is fair to say that it is a problem we must wrestle with. To assume that it is a problem is to assume that the state of Earth's climate today is the optimal climate, the best climate that we could have or ever have had and that we need to take steps to make sure that it doesn't change. I guess I would ask which human beings - where and when - are to be accorded the privilege of deciding that this particular climate that we have right here today, right now is the best climate for all other human beings. I think that's a rather arrogant position for people to take.
Precious.

I have always believed that the people who actually work with hard sciences and technology simply shouldn't buy a cheap and soft pseudoscientific propaganda such as the "fight against climate change". NASA has been doing many amazing and non-trivial things and they must also be irritated when pseudoscience based on such shaky and unscientific notions is given so much attention - in fact, breathtakingly, more than NASA's space program itself.

The ideology of a "fight against climate change" is based on a whole network of assumptions - dozens of assumptions each of which is highly questionable, to say the least. As long as we are a scientifically inclined society, each of these assumptions should be studied separately because rationally speaking, they are independent.

One of these assumptions says that the current climate is better than a different climate and it should be preserved. It is an arbitrary, irrational assumption that was also recently criticized by Czech president Klaus in his book, among other people.




Needless to say, a different kind of scientists such as NASA's own James Hansen responded in an irritated way. But NASA is not primarily the home of strange scientists who "prove" a 20-meter sea level rise using the concept of scientific reticence.



Antimatter spaceship for Mars missions that the NASA administrator likes (click)

NASA is primarily the home of serious engineers and scientists who are doing some truly impressive stuff - besides the spaceships and devices telling us so much about cosmology, we also find climate-related activities including the stuff about the satellite measurements of temperatures and about cosmic influences on our climate. These are the real sources of NASA's natural authority: James Hansen is not.

The Reference Frame applauds Michael Griffin and encourages him to act as a self-confident boss of a highly prestigious institution. Let me re-emphasize that it is Griffin, not Hansen, who is the boss of NASA and this fact should be taken into account if it turns out that one of them should leave NASA. Any sign of weakness, Dr Griffin, will be used against you. More precisely, I would recommend the boss of NASA to fire Hansen for his despicable comments about his boss as soon as possible.

And that's the memo. (Via Bob Ferguson.)

P.S. So far, Dr Griffin, BS MS MS2 MBA MEng Civil MEng Aerospace PhD is doing very well. For example, they have published the following press release:

  • NASA is the world's preeminent organization in the study of Earth and the conditions that contribute to climate change and global warming. The agency is responsible for collecting data that is used by the science community and policy makers as part of an ongoing discussion regarding our planet's evolving systems. It is NASA's responsibility to collect, analyze and release information. It is not NASA's mission to make policy regarding possible climate change mitigation strategies. As I stated in the NPR interview, we are proud of our role and I believe we do it well.

But Griffin must be ready to act in the same way even if the pressure quintuples. Immoral politicians such as Bart Gordon as well as radical communists will suddenly invent criticisms of NASA's work. If Griffin can resist for three weeks or so, things will be OK.

What to do in Houston this weekend (and this month)

First, from Houston's least obnoxious conservo-blog (Vikk does a good write-up but I edited some of his dry snark):

Brazos Bookstore (2421 Bissonnet) has a triple-header this weekend for H-Town's Democrats, liberals, and/or progressives and it begins tonight. ...

Thursday, May 31, 6:00 PM
What do you get when you combine California, the Beat Generation, and the 1960s? Apparently something called the "religion of no religion." Jeffrey Kripal explains it all tonight in his book ESALEN: America and the Religion of No Religion.

Friday, June 1, 12:00 -2:00 PM
It would seem that Senator Kerry is still looking for his moment. This time he--and his wife--have cast their eyes on the future and come up with a new book: THIS MOMENT ON EARTH: Today's Environmentalists and Their Vision for the Future. This is a 2-hour event, so fans will probably want to get to the store early. ...

Saturday, June 2, 5:30-7:30 PM
Molly Ivins brought much joy and laughter to her audience. Saturday's event has been crafted to bring out the best of Molly and her friends with an open microphone, stories, and readings. "The Celebration of the Life and Work of Molly Ivins" festivities will include the following special guests: Lou Dubose, Molly's co-author; Charlotte McCann, publisher of the Texas Observer; Betsy Moon, Molly's "Chief of Stuff", the Chronicle's Leon Hale; and Andy and Carla Ivins. A "Special Molly Issue" of the Texas Observer will be available. There is a $10 cover charge to help defray the cost of refreshments and the bookstore asks that you bring the correct change. Since the wine and beer will be flowing, I'm sure you can expect the unexpected.


There's also these events ...

Annie's List training for potential political candidates (I can think of several local women I'd like to see run for office):

Are you a Democratic woman who has thought about running for office or would like to get more involved in helping local Democrats win? If so, Annie's List has an exciting opportunity for you to learn more about what it takes to run for office and win campaigns and network with like-minded women in Houston.

We are hosting a free campaign training during the day on Saturday, June 2nd that is available on a first come, first serve basis to all progressive, Democratic women. Topics such as fundraising, press relations, voter targeting, message development, planning to run for office and more will be covered. All meals and training materials are provided at no charge to participants who commit to stay for the entirety of the training (8:30am - 5:00pm).

Reserve your spot by REGISTERING ONLINE today as space is limited!
http://www.annieslist.com/register.php

Democracy for Houston is having a Presidential Debate Watch Party this Sunday evening. If you're tired of watching Grumpy Old Rich White Men arguing over who has the biggest penis, then you have another option, and that's to get a look at the next President -- and likely, Vice-President -- of the United States talk about an America without Bush's War and with health care for everyone. RSVP here.

Next Saturday the 9th the ROADWomen are having their "True Blue Texas Women" luncheon, with author Melinda Henneberger as one of the many keynoters. Look who else will be there:



Henneberger's publicist sent me a copy of If They Had Only Listened To Us and I'll have a review and excerpts next week in advance of this event.

And on Sunday the 10th is the Environmental Summit:

What's happening with the Houston region environment? How bad is it?

The people of Houston suffer the ill effects day in and day out and seem unable to make their voices heard by most elected officials. What can we do?

Come to the Environmental Summit on Sunday, June 10 from 1-5 p.m. at the University of Houston's University Center, 4800 Calhoun, to find out what's happening, who's working for the people of Houston, what you can do, and how we can all work together.

The event, sponsored by the Harris County Democrats progressive organization and the Billie Carr Institute, will feature a keynote by Houston Mayor Bill White and introductory comments by well-known environmental activist Jim Blackburn. In addition, Dr. Stephen Klineberg of Rice University will discuss survey research about environmental opinions and renowned climate change expert Jim Marston will speak, and a variety of environmental and political groups will offer comments about environmental goals, issues and key challenges in the near future.

The event's objectives are to broadly increase knowledge of environmental issues and introduce organizations to political activists of Harris County and surrounding areas. We hope to substantially increase interaction between people active in environmental issues and partisan politics. Ultimately, we'd like to plan future interactions for the coming election season.

Houston Region Sierra Club, GHASP (Galveston-Houston Association for Smog Prevention), Mothers for Clean Air, Houston Audubon Society, Galveston Bay Foundation, Citizen's Environmental Coalition, AND Harris County Democrats, Bay Area New Democrats (BAND), and other Democratic organizations are
expected to participate.

Organizations are encouraged to invite their members and to staff tables with literature throughout the event in the main ballroom of UH's University Center.

No pre-registration required, $10 admission. Check www.harriscountydemocrats.org for more information.


Maybe I'll finally get to meet you at one of these this month?

Alas, there is more

"Separated at Birth":


Wednesday, May 30, 2007

Separated at birth?



We report. You decide.

Eleventh elderly rich white Republican enters race

The co-star of Curly Sue, the one who has Republicans everywhere wet with pleasure, is "testing the waters". His presidential campaign committee, "Friends of Fred Thompson" -- rhymes with 'soft' -- will raise money for him without his actually having to say he's running.

This news naturally has the hearts of Houston conservatives aflutter. Because there's nothing like an unemployed actor that screams "WHITE HOUSE" in their heads.

Let's briefly review the man's career:

2007: Warming up for his turn in the spotlight, Thompson puts on a hairpiece and portrays President Ulysses S. Grant for the HBO docu-drama Bury My Heart at Wounded Knee. During his one scene and ten seconds of screen time, he grumbles and smokes a cigar. Obviously a method actor.

Also this year: responding to Michael Moore's challenge to debate him on health care policy, Thompson has a YouTube filmed of him grumbling and chewing a cigar.

Is there a pattern here?

-- Too many years to bother counting: his portrayal of New York district attorney Arthur Branch spanned four different versions of the TV show "Law and Order".

His film roles would make a pretty good resume' for an aspiring politician, if they had not been film roles, of course: CIA director in No Way Out; a Senator (himself) in Albert Brooks' Looking for Comedy in the Muslim World; a major general in Fat Man and Little Boy and a rear admiral in The Hunt for Red October. He played Racehorse Haynes in the "special TV event" Bed of Lies and former AmEx chief and corporate sleaze Jim Robinson in HBO's Barbarians at the Gate (two roles also requiring precious little departure from his everyday life).

I'd say he's eminently qualified to be the GOP nominee. I really hope he can turn back the likes of Sam Brownback and Tom Tancredo, because compared to them he's positively liberal.

Registered users can vote in the poll

here:

As a result of the congressional vote on Iraq funding last week ...

1%61 votes
3%174 votes
22%1169 votes
24%1305 votes
19%1009 votes
8%454 votes
5%260 votes
1%38 votes
1%59 votes
2%101 votes
2%101 votes
7%360 votes
1%56 votes
3%173 votes
2%105 votes
| 5425 votes

I'm in the at-the-moment 24% majority.

Tuesday, May 29, 2007

George Bush will visit Prague next week

See also: Bush in Prague and rockets, not radars and Bush liked the dumplings
Laura Bush plans to enjoy gardens of the Prague Castle, together with Lívia Klausová, the Czech first lady who is Slovak.



George Bush has to see the headquarters of the Radio Free Europe / Radio Liberty in Prague, a building that used to be the communist Parliament.



Most Czechs are looking forward to see the Bush family. However, Martina Navrátilová wants to get her Czech citizenship back to protest against the "Bush regime". ;-)

Russia has successfully tested a new intercontinental ballistic missile system (ICBM) that can beat anyone. Our Slavic brothers in Moscow's Izvestia daily have calculated that they need 15 minutes to destroy Czechia by nukes if the country hosts the missile defense system. Polish officials have correctly identified this position of the Russian brothers as their mental problem. ;-)

Cindy Sheehan's grief and rage

Will hopefully and shortly come to an end:

The most devastating conclusion that I reached this morning, however, was that Casey did indeed die for nothing. His precious lifeblood drained out in a country far away from his family who loves him, killed by his own country which is beholden to and run by a war machine that even controls what we think. I have tried ever since he died to make his sacrifice meaningful. Casey died for a country which cares more about who will be the next American Idol than how many people will be killed in the next few months while Democrats and Republicans play politics with human lives. It is so painful to me to know that I bought into this system for so many years and Casey paid the price for that allegiance. I failed my boy and that hurts the most.


I went to Camp Casey the weekend before Hurricane Katrina hit New Orleans. It was one of the most seminal experiences of my life. Sheehan organized the anti-war movement when 70% of Americans believed George Bush and his lies. Now, of course, 70% don't, but as Sheehan points out the Democrats in Congress who were elected to stop the war have failed us all in their duty to do so.

And even as she exits, the flying monkeys fling their poo at her.

I hope Cindy Sheehan finds peace.

"Surf's Up" in the San Antonio Current

Ironically this feature is one of the only things that doesn't make it into the online edition, so you'll have to pick a copy of last week's San Antonio Current to verify if this is the truth:

A hundred years from now, history may very well remember Perry Dorrell as one of the founding pillars of the Texas blogosphere, having launched his Brains and Eggs in 2002 after a long career working on the executive side of the Texas print media, including a stint with Hearst, parent of San Antonio's daily. Since then, he's developed Brains and Eggs into a serrated, left-heavy journal covering everything political on the national, state, and local (Houston, where he's based) fronts. Dorrell's also a veteran of Texas politics, having served as statewide coordinator of David Van Os' (failed) 2006 bid for Texas Attorney General. Check out Dorrell's recent posts on George Irish, former publisher of the San Antonio Light, as well as his weekly "Sunday Funnies" posts, a compilation of the week's best leftish cartoons, similar to MSNBC's Daily Political Cartoon Index (cagle.msnbc.com).


*buffs, then admires manicure*

Europe isolated over Kyoto

China, India, Russia reject carbon cuts. Australia realizes that the Kyoto has had no desirable effect.

Nominally right-wing German government is trying to convince the US government to impose caps. But Nancy Pelosi didn't offer the Germans much support.



Other two countries with nominally right-wing governments, Japan and Canada, want to reduce the CO2 emissions by 50% even if they have to pay for the third world and the U.S. However, both Republicans and Democrats want something slightly different, namely to subsidize coal.

It would be a mistake to think that the Japanese actually want to impose all these suicidal restrictions. Today, Japan refused to follow a new EU plan to stop climate from changing.

While Harper's people try to behave as greenies, they are being sued by Canadian ecoterrorists. That's where any kind of appeasement always leads.

When I suggested that right-wing politicians in many countries have started to do a lot of insane things, I should also mention that the German social democrats actually warn Merkel's government that a climate dispute against the U.S. could be dangerous. G8 is very far from a consensus and Europe is isolated over Kyoto.

But I don't mean the whole Europe. Poland and Czechia join Slovakia and all of them sue the European commission over its arrogant bureaucratic attempts to heavily reduce the CO2 emissions in these three fast-growing economies.

Today, the price of the European 2007 indulgences closed at 27 eurocents, more than two orders of magnitude below the price one year ago, but the gigantic worldwide fraud continues.

Via Benny Peiser.

P.S. Václav Klaus' book against the anti-greenhouse religion is now the #1 bestseller on kosmas.cz, a Czech counterpart of amazon.com. Al Gore's book is at #9.

Lampson is not in for the Senate, and more bloggerrhea

Just a week ago I confidently posted that Nick Lampson would declare his challenge to Senator Box Turtle for the US Senate in 2008, but yesterday Lampson, through his local spokesperson Mustafa Tameez, told the Austin American-Statesman he was a no-go:

A Senate bid is “not going to happen,” Tameez said. “It sounds goofy, but he feels like he made a commitment to the people of Congressional District 22.” Tameez said Lampson feels a Senate try would be “disingenuous.”


I am delighted to have misread the tea leaves. Of course I am more inclined to believe that the blogswarm over his dithering forced him to reconsider, but that's only because I have an inflated sense of self-importance. And considering he's at the top of Karl Rove's hitlist, he'd better go to work right now nailing down his seat in the House.

Elsewhere:

-- "Lyndon Johnson's mistress claims LBJ told her that he had JFK killed!"

-- Paul Burka found Tom Craddick in a bald-face contradiction. I'm shockedIsay.

-- The terrorists are NOT going to follow us home (so stop staying that):

The President and his supporters have been repeatedly expressing their concern that if US troops left Iraq before the war is "won" as they define it, Al Qaeda in Iraq would follow us home and carry out their terror campaigns in the streets of America instead of Baghdad. Critics like myself are suggesting the President has chosen once again to engage in fear-mongering to try to manipulate American public opinion on the war. He has done so in a desperate attempt to rationalize our continued occupation in the hope of salvaging his, and his party's, legacy. In the end, his and his supporters' claims will be proven to be just as self-serving, misguided, and delusional as the claims they made leading up to the war in Iraq about Saddam's WMDs, mushroom clouds, and being greeted as liberators.

Ironically, the only way they would have followed us home would have been if George W. Bush had actually succeeded in imposing his will on the people of the Middle East. Then they would have followed us home for revenge, much like they did on 9/11. Otherwise, they are no more or less likely to follow us home any more than we did the British, or the Viet Cong did us.


-- The movie critic at FOX News loves Michael Moore's new movie, SiCKO. There's hope for everything.

-- New sponsors of this blog include the National Cheney Impeachment Poll. Here, have an Impeachmint.

Myths about Einstein

The New York Reviews of Books have published a text by Lee Smolin who uses several recent books about Albert Einstein to define his opinions about the famous physicist. There are many points in Smolin's text that I consider correct and many more things that I consider silly. Let me start with some of the correct ones:
  • It is indeed true that people tend to incorrectly think that the revolutionary Einstein was a detached immaterial, spiritual, peaceful sage - an idealized image constructed according to Einstein when he was old. Instead, the real revolutionary Einstein was a young chap with a rather contrived personal life who assertively tried to transform the world according to his visions. I am sure that much like many other similar people, young Einstein was deeply offended by stupid folks who wanted to act as authorities.
  • The ideas that Einstein's personal life resembled the life of the (idealized) Jesus Christ are myths.
  • Einstein's disbelief in quantum mechanics was the main technical reason why the last 3 decades of his life didn't lead to important scientific results.
  • He may have become "officially" irrelevant at the IAS when the younger generation, realizing that Einstein's opinions about cutting edge physics have become silly, decided to transform Einstein into nothing an idealized but impotent symbol.
  • Albert Einstein's political abilities were non-trivial and he had the technical skills to be a top-tier politician, including the president of Israel if he wanted.

However, as I have mentioned, there are many more crazy thoughts in Smolin's text.



First of all, Smolin tries to picture Einstein's personal life and his political methods and attitudes as a key aspect of his personality that is essential to understand his creativity or even the technical content of his greatest discoveries. I think it is a completely silly association. There are no direct, rational links between Einstein's creativity on one side and details of his love affairs or political opinions on the other side.

These two projections of Einstein are largely independent of one another. Relativity and other theories could have been found by very different personalities. Whoever thinks that a detailed analysis of Einstein's love affairs allows us to speed up scientific revolutions in the future is crazy.

Smolin implicitly claims that these things are inevitably synchronized which I view as another example of Smolin's inability to think rationally about science. Smolin simply can't or doesn't want to distinguish science from sociology and from love affairs.




More generally, various pundits such as Mark Trodden claim that it is wrong if scientists are painted as people who are detached from material life. It is clear that such a picture is an oversimplification and that scientists are often ordinary people in many respects but on the other hand, I do think that scientists should fit this description more accurately than other people in many more cases. And many of them actually do. Painting scientists as "completely" ordinary people is a misrepresentation of science - or at least a misrepresentation of what science should be. More seriously, it is a hidden attempt to vulgarize science and attract all sorts of idiots into it who are driven by very different things than the passion for the truth. I think that there are already way too many idiots like that in institutionalized science.

Importance of Einstein's personal life and politics

Another weird thing about Smolin's approach to Einstein is the way how he wants the society to judge Einstein's personal ethics and political attitudes. Einstein has surely done, said, and written many things that many groups of people would dislike. But is there an objective method to decide whether Einstein has done the right thing or whether his critics would be right? Smolin thinks that there is one, I don't.

Smolin seems to criticize Einstein's political opinions. Einstein was a socialist, anti-communist, pacifist (at least before he realized how dangerous the Nazis were), and Zionist. Well, I would only subscribe to anti-communism and Zionism in this list ;-) but I don't understand how Smolin can write that "the man [Einstein] himself was an embarrassment." What the hell does it mean?

Einstein held certain political and other opinions. These opinions were rather coherent and there have always been reasons for wise people to listen to him. I may disagree with some of Einstein's opinions but I can't pick Einstein as a scapeboat who should be described as "an embarrassment". There have been millions of pacifists and socialists around.

The same Smolin who is producing hundreds of essays about mad social-engineering projects to increase the "diversity" is always ready to divide people to the correct people on one side and "embarrassments" on the other side. In this case, Einstein wasn't too lucky because Smolin's PC police have transformed him into an embarrassment. Smolin even seems to agree with a director of the IAS who was opening Einstein's mail to prevent him from meeting the U.S. president, among others. I personally think that this treatment of Einstein's privacy was despicable and those who were doing these things had absolutely no credentials for their acts.

What Einstein has thought about politics is no longer a primary question that determines my opinions about politics today - even though the personality of Einstein has influenced me tremendously when I was a teenager. But what a director of an institute thought 50 years ago is even more irrelevant. I just can't understand why Lee Smolin thinks that it's important whether a particular opinion of Einstein was considered to be an embarrassment by an irrelevant director.

Smolin also criticizes Isaacson, the author of one of the books, for claiming that we shouldn't be overly concerned by Einstein's rough edges. I happen to agree with Isaacson. Einstein is such an important personality that his rough edges, whatever they are, are either secondary characteristics or inevitable by-products of his ingenious mind. Another thing that Smolin dislikes about Isaacson's book is that Isaacson claims that Einstein has underestimated the resilience of American democracy when he was very worried about McCarthyism.

Smolin asks: "Why does Isaacson feel he has to assure us that we don't need to take his subject's political views too seriously?" Well, the answer is that Isaacson realizes that history has proven that Einstein's worries about this point and similar points were not justified and Einstein's political opinions - in this case somewhat misled opinions - were simply not terribly important even though they were clearly more important than the opinions of an average person or an average physicist. Why does Smolin feel that the political opinions of Einstein were more important?

Einsteinian stamp on theories

At the end of his text, Smolin displays his uncontrollably huge reliance on authorities when he suggests that some misguided attempts of an old Einstein to revolutionize science once again should be viewed as an argument to support various kinds of contemporary crackpots such as those who envision a discrete spacetime or those who still haven't understood or accepted the probabilistic nature of quantum mechanics.

I simply think that this approach of Lee is mad. Einstein could have afforded to have held these silly views simply because he had already made it. But there was nothing spectacular about the theories he was writing down in his last 30 years. If these theories were the only thing Einstein represented, there would be no reason to hire him or celebrate him.

And if you think about some parrots who would be just indirectly copying these later theories of Einstein or emulating his flawed way of thinking (and maybe even 50 years after his death) but who have never done anything comparable to what the young Einstein did, it is even more obvious that their work doesn't deserve to be supported. I think that no sane person in science would ever suggest that the society should be supporting people who only try to imitate a well-known personality's acts during an era when he was already irrelevant. Nevertheless, that's exactly what Smolin seems to propose.

Lee Smolin, the same man who often talks about original scientists, reveals that he actually likes something completely different, namely if young people are writing even more confused parodies of his and other narrow-minded and physically naive papers that should be viewed as important because they resemble the flavor of some basic misunderstandings of a genius that were written when he was already unspectacular. That's one of the reasons why he surrounds himself with loads of untalented people who only say Yes Mr Smolin. He also likes when people's opinions about the society are judged according to a universal, politically correct criterion.

Moreover, Smolin tries to discuss whether the new developments in string theory follow the philosophy of Einstein. Other people including myself sometimes talk about these questions as well but it is very important to realize that any kind of an answer to this question is an artificially created story. Einstein was trying to answer different questions in a different context and there is no one-to-one correspondence between the answers to some questions in the 1950s and answers to the present questions in 2000s.

Even if there were some correspondence, the "Einsteinian stamp" wouldn't influence the contemporary scientists' decisions about the validity or value of their theories as long as they would be scientists. Smolin seems to care about the "Einsteinian stamp" and similar rituals a lot which is another profoundly unscientific feature of his approach.

Is string theory a continuation of Einstein's dreams to find a unified field theory? Well, it is certainly a continuation of his attempts to figure out verifiable and mathematically elegant laws that account for all forces. At this superficial level, all string theorists are inheritors of Einstein's legacy, even the legacy of the old misled Einstein. From a more technical perspective, however, it's the other way around. String theory is a full-fledged quantum mechanical theory that is fully accepting the premises that Niels Bohr and his friends believed and that is taking the observations and the detailed work of many careful scientists very seriously, unlike the old Einstein.

String theory surely reveals the kind of beauty and depth that we normally associate with Einstein and his dreams but Einstein wouldn't have been able to work on it because he didn't appreciate quantum mechanics.



Einstein, stop telling God what to do with his dice!

If you look at these aspects of Einstein's approach, string theory is clearly the inheritor of the quantum mechanical generation while various loop quantum gravitational and related alternative physicists are inheritors of Einstein's flawed and superficial games attempting to find some extremely simple-minded laws and to convince everyone else (and themselves) that these naive laws should govern the whole Cosmos, regardless of any evidence and any "details".

It is clear that certain aspects of "good science" - at least most of these aspects - are found in the context of many important discoveries. Analogously, certain aspects of "bad science" are frequently associated with attempts that didn't lead anywhere, including attempts of famous scientists who had already "lost it". For example, if someone loses a contact with all newly discovered "details", it is a bad thing.

As we have already mentioned, Smolin apparently tries to do something completely different than a rational analysis of various aspects of Einstein's life and ideas and their actual causal relationships. He wants to attach the same stickers to ideas and approaches in different contexts, using superficial sociological similarities as a justification, and divide them to "good" ideas of "seers" and "bad" ideas of "craftsmen" according to these superficial keys. Such an algorithm is all but guaranteed to lead to nothing else than noise which is indeed what Smolin writes in more than 90% of cases.

Best strategies keep on changing

Another fundamental fact about the philosophy of science that Smolin and dozens of other critics of science seem completely unable to comprehend is that there is no eternal and universal set of rules that would tell you how to make progress in science or that would determine what the society should do to make this progress happen. Einstein's talent combined with his basic philosophical assumptions were important for many of his earlier discoveries and they allowed him to find many important things including general relativity.

But the same strategy simply didn't work afterwards. It couldn't have been clear a priori whether his disciplined search for beautiful deterministic laws describing physics could have led to further breakthroughs. Nevertheless, the answer turned out to be No. Quantum mechanics has revolutionized the framework in which important cutting edge physical theories had to be formulated. Einstein didn't want to or wasn't able to absorb this additional paradigm shift and this simple fact has become a severe limitation that guaranteed that virtually all of his later work was irrelevant and misguided.

But it could have been otherwise. If Nature were organized a little bit differently, Einstein could have discovered special relativity in 1905, general relativity in 1915, and divine relativity in 1925. There is no philosophical or sociological law that would guarantee that such a scenario was a priori impossible. But once you look into the structure of physics, you will see that there is no divine relativity. Nature happens to work differently and all really important new results in theoretical physics after 1925 rely on quantum mechanics in one way or another.

Lee Smolin also tries to pretend that Einstein was still a leader in the middle 1930s, using his paper with Podolsky and Rosen as an example. OK, I don't think it's true. The EPR entanglement (improved by insights of Bell and others) has become a popular way to express some of the most surprising features of quantum mechanics. But it didn't really lead to an increased ability to make predictions. The quantum mechanical heroes knew how to predict the results of all thought experiments (and real experiments) that Einstein designed for them. Moreover, both sides of the debate deserve credit for having defined the questions about entanglement. Most importantly, Einstein's answers were wrong. I happen to think that it is not an irrelevant detail to see who was right and who was wrong. Most of my respect towards Einstein's criticism results from Einstein's previous amazing contributions. If someone else were saying these things about quantum mechanics, I would think that he is simply dense.

Smolin chastises Freeman Dyson and others for believing that famous old men like Einstein were making fools of themselves by expecting another conceptual revolution as profound as the quantum mechanical revolution. Dyson and others realized that this expectation was completely silly and that the following century in theoretical physics would be built on the same postulates of quantum mechanics that were known to Bohr.

Lee Smolin doesn't like the opinion that after quantum mechanics was found, the major conceptual revolutions were over. Smolin doesn't seem to care that Dyson's thesis that quantum mechanics is the correct framework to describe the world is by 10 orders of magnitude at the energy scale and by 60 years more powerful than when Dyson expressed them for the first time. Again, I don't think that these additional developments are details that can be ignored. Whoever ignores them is making an even greater fool of himself than he is.

Peter Galison's theories

Other scholars offer some opinions that I find strange, too. In his 2003 book, Peter Galison tried to argue that Einstein has found special relativity primarily because he was working with train synchronization patents and because his father and uncle did some business in technology.

From the viewpoint of the actual historical resources showing how Einstein was looking for the answers, I have always found these theories extremely unconvincing. The details about his family and jobs look like unimportant curiosities. Already as a teenager, Einstein was demonstrably asking questions what happens with light if you try to chase it. He was aware of some tension between the Galilean transformations on one side and Maxwell's equations on the other side. He decided to solve this problem, and he did so. It was a theorist's approach par excellence and almost any profession of his father and uncle could be painted as being instrumental in Einstein's discoveries.

Technical jobs are surely helpful but on the other hand, it is very clear that there were lots of people around whose background was expected to be much more useful for making similar breakthroughs than Einstein's background. Einstein's contributions were huge. They were arguably surprising but they were not physically impossible. His life has been affected by many social phenomena and personal affairs but these social events are not the most critical aspect of Einstein's personality. I am always amazed how people - including historians of science - misunderstand not only the way how people like Einstein were thinking but how they misunderstand what was actually important and what was unimportant.

And that's the memo.

Monday, May 28, 2007

Bussard's IEC fusion for dummies: video



Two minutes of video by Foger Rox explaining Robert Bussard's reactor. See also emc2fusion.org. If you ask me how does the geometry from the video lead to fusion, you are not the only one who asks! ;-)

Via M. Simon.

Doomsday arguments

Sabine has written an essay about the doomsday arguments. If I understand her well, I think that the two of us agree. But it may be useful to mention which of the assumptions are rational or justified and which of them are not. Let me start with the

Copernican Principle

The principle says that the Earth is not a privileged celestial body, the Sun is not a privileged star, and the Milky Way is not a privileged galaxy. A generalization of the principle says that the humans are not a privileged species. A more ambitious version of the principle, the mediocrity principle, is the actual driving force of many people who believe the anthropic principle. All these people must believe in some kind of integalactic democracy that gives the same voice to every single intelligent observer within the Galaxy or even the multiverse.

Is the principle universally true and profound?

Well, I wouldn't say so. What would you expect from a person who doesn't even believe in trans-national democracy and who thinks that even the equality within one country is just a convenient law that can never quite work de facto?

In my opinion, the original version of the Copernican principle was mainly an ideological tool to oppose a wrong theory of astronomy, namely a theory that has always been driven by religious and political forces rather than scientific arguments. The Catholic black-buttockers used to insist that the Earth had to play as special a role in the Universe as it played in their favorite book, the Old Testament. While Christianity has made many great things for the Western civilization, its stubborn belief in certain ancient astrophysical theories - and later also biological theories - turned out to be counterproductive at a certain point. The Copernican principle is a symbol of the revolt against the religious dogmas.

In the case of the Earth, Copernicus and his soulmates were right. The physical parameters of our planet don't differ from the parameters of other planets in some spectacular qualitative way.

However, we should ask: Was this conclusion inevitable? Is there a permanent physical principle that tells you that things always turn out to be less special than they are believed at the beginning? My answer is a resounding "No". If you declare that things are not special but they are rather generic, you only choose a probability distribution that describes your ignorance more faithfully.

But it is not true that as we continue to learn how the real world works, objects are constantly becoming less special. Sometimes they are becoming more special and less equal. All values of wavelengths of light may a priori look equally natural and likely but the 21.1 centimeter line turns out to be rather special in astrophysics, after all.

Billions of other insights of all sciences - essentially all insights we have - may be viewed as additional examples of objects and numbers becoming more special than they used to be before you have a learned a new fact or before you have written down a new theory. When we look more carefully, the Earth has certain features that also make it somewhat special, after all. You can also find features of homo sapiens that make our species more viable and more intelligent than many others.

As you can see, I view all kinds of mediocrity arguments to be a tool to construct quasi-realistic "priors" - expectations that you insert as a starting point for your logical inference. These arguments represent a tool to avoid unjustified dogmas. These arguments seem to be a more fair description of your primordial ignorance. However, they are definitely not unbreakable constraints that the final answers must confirm.

Naturalness

Naturalness is another example. If you deal with an effective field theory, are all dimensionless couplings inevitably comparable to one? Once again, the answer is clearly "No". Why do we expect that is should "normally" be so? Well, it's because we describe our ignorance by a uniform prior. With a uniform probability distribution for a certain dimensionless parameter, it is unlikely that the parameter will be extremely tiny.

But the uniform probabilistic distribution is not a God-given law of the Cosmos. It is just a convenient trick to make balanced expectations - expectations that often turn out to be wrong anyway as soon as we figure out how the system works in more detail, as soon as we discover new reasons that make some special expectations more meaningful. Naturalness is thus not an unbreakable law of physics either. Even if you are a huge optimist, it is just a useful tool to quantify how unexpected the values of numerical parameters within a certain framework are.

Doomsday argument

The doomsday argument is an example of the mediocrity reasoning that is even worse than just an unjustified prejudice: I think that in this case, the conclusions of a mediocrity argument are manifestly flawed.

The argument assumes that you should be a generic observer. Because the number of people on the Earth grows exponentially, most people during the history live right before the collapse of the civilization. That's why the doomsday argument leads many people to predict that the humankind will collapse pretty soon. Jehovah's Witnesses as well as Anthropogenic Global Warming bigots, among dozens of similar groups, surely consider the doomsday arguments to be a general weapon that strengthens their predictions about the judgment day.

Are they right?

We can't be quite sure whether their particular predictions are going to be right - except for the predictions that have already been falsified - but we can be absolutely sure that the method with which they have reached their conclusions are completely irrational. Why? It's because we actually know the laws that will decide about the collapse of the civilization. More precisely, we know them partially but well enough to falsify certain oversimplified doomsday calculations.

Whether or not men will be around in 2100 and whether or not the future civilization is going to be stronger than ours will depend on the success of our fight against Islamic terrorists, North Korean communists, environmental terrorists, diseases, political correctness, shrinking fossil fuel resources, mutated viruses, left-wing nutcases who want to cripple the world's economy just for the sake of it, dangerous asteroids, or dozens of other potential threats you could think about. When you understand how these things work, you may offer qualified estimates of the probability that all of us will be screwed by 2100.

Even though we are clearly not able to make perfect predictions about the world in 2100 - not even good predictions - it seems clear to me that the method of looking into particular threats and their internal mechanisms is much more rational and reliable a way to deduce the future of mankind than some general doomsday arguments. I believe that if we understand the microscopic mechanisms of the dangerous processes in depth, we can make essentially accurate predictions of certain phenomena.

There is absolutely no reason to think that such predictions calculated from an increasingly detailed and accurate microscopic description of these phenomena will agree with some simple stochastic predictions based on the doomsday arguments or the mediocrity arguments. And if the two approaches to make predictions disagree, be sure that your humble correspondent prefers the microscopic analysis of the terrorists, asteroids, or viruses.

Such a contradiction means that one of the frameworks to predict has to be wrong. It is the mediocrity framework that is wrong. The only acceptable reason why a mediocrity argument should be right is a causal mechanism that is included among the laws of Nature. Such a mechanism would have to be somewhat analogous to thermalization: thermalization is a process that naturally makes all microstates with the same values of macroscopic parameters equally likely.

But as soon as we find out that the answers to various questions are actually decided by mechanisms different from such generalized thermalization or as soon as we find out that such hypothetical thermalization mechanisms would contradict causality and other well-established principles, these thermalization mechanisms that were invented to produce uniform distributions are simply falsified.

In the case of the doomsday arguments, we simply know that the answer to the question "When will the last humans die?" manifestly depends on other questions than those that enter the doomsday argument calculations.

Another recent example have been the Jovian citizens - those who live on Jupiter. Should the number of Jovian beings predicted by a theory influence our confidence that a particular theory is right before we actually count how many people live there? I have argued, together with Hartle and Srednicki, that the answer is "No". Theories become more acceptable or less acceptable once we compare their predictions to phenomena that we can already check and once we see an agreement or a disagreement. This is the right method to refine the probability estimates that a theory is correct. Predictions that we are not yet able to test - confirm or rule out - can't influence our confidence in a theory as long as we remain rational.

Analogously, if someone believes that the world should collapse because of some mediocrity argument, he or she is just a victim of another irrational prejudice. This prejudice might have the opposite flavor than the typical prejudices imposed upon our ancestors by Christianity. But this opposite flavor doesn't make these prejudices correct. They are equally irrational as the Christian dogmas.

Moreover, there exist methods to use the mediocrity arguments that lead to very different conclusions. For example, a mediocrity argument may be used to argue that the present can't be a special moment in the history of the Universe (or mankind) because all moments are created equal. Such a conclusion sharply contradicts the gloomy predictions of the usual doomsday arguments.

Summary

If you allow me to summarize, I view all kinds of mediocrity arguments to be nothing else than a very rough method to decide about your expectations long before you know anything about the system you study. Once you start to understand how various systems work, you may instantly realize that the expectations based on the mediocrity principle were just wrong. There exists no God-given rule that an egalitarian viewpoint based on uniform distributions is closer to the truth than the viewpoint of someone who avoids the mediocrity arguments.

Also, if you can prove that there can exist no mechanism that would be creating certain uniform distributions but that would still be consistent with other well-known facts about the Universe, the mediocrity argument is ruled out, too. Various types of thermal equilibrium of intelligent observers who live in different parts of a huge multiverse and at different moments are probably incompatible with the rest of physics we know.

We should carefully avoid unjustified dogmas about the special nature of our environment or our species or ourselves but we should also avoid unjustified dogmas claiming that these things can't be special.

And that's the memo.

Some trips

During the last two weekends (and some days around them), we have been away to see The Statue of Liberty, Empire State Building, Niagara Falls (boats, caves), Thousand Islands, Salem (105 km on bike in 34 Celsius degrees), New England Aquarium, Navy Yard so I apologize for the silence.

Among the six movies in the bus, I would recommend you The Princess Diaries 2 (2004). A princess of Genovia finishes her college but can't become a queen unless she's married. So she eventually agrees to find and marry a perfect-on-paper husband within weeks. Opposing political forces try to prevent the wedding. Needless to say, the guy whose task is to stop the wedding falls in love with Mia and she loves him, too. Eventually she is able, in the middle of the wedding ceremony, to abolish the queen-must-be-married law, becomes a queen, but marries the real lover anyway later.

My #2 choice is What Women Want (2000). Mel Gibson is a creator of commercials for cosmetics products. A serious incident with a hair dryer (electrical shock) allows him to "hear" what women really think but can't say. He becomes a sex god & successful creator of the commercials by reading his blonde colleague's thoughts. She finally forgives him and a happy end follows.

Saturday, May 26, 2007

Craddick Coup continues today

There was a revolt last night in the Texas House.

BOR followed the action (several other threads provided play-by-play as well). The House parliamentarians resigned due to the dictatorial will of Speaker Craddick. He replaced them with his stooge, former Rep. Terry Keel, who literally fed the Speaker his lines. (Muse had the quick wit on this comic drama.) Craddick refused to recognize motions -- even from Republicans like Fred Hill -- to consider the vacation of the chair.

Parliamentary procedure denied, the House was in an uproar most of the late evening and early morning, at the end of the legislative session, with numerous bills still to be considered. An historical pandemonium -- not since 1871 has a motion to vacate the chair been advanced -- and Craddick declared that occurrence divined no precedent in this case. He declared that any attempt to remove him would have to be an impeachment proceeding, requiring a two/thirds majority of the House's members to advance.

Update (ten minutes after original post): Via Eye on Williamson, John Kelso applies the, uh, coup de grace:

Mention Craddick’s name and the words “mean,” “small” and “autocratic” come up. I’ve heard him called autocratic so often I’m surprised they haven’t started calling him Otto — as in “Otto” Craddick.

So nevermind being civilized.

Just wait till he’s not there. Then send a moving crew of members into his posh 2,000-square-foot apartment behind the House chamber, and leave his stuff out on the Capitol lawn on bulky trash day.


Today the House reconvenes, at 11 a.m. Quite a few more of us will be watching.

Thursday, May 24, 2007

Sparrow makes statement on Bush's statement on Gonzales

ABC's Ann Compton reports: An outdoor news conference in perfect spring weather, with birds chirping loudly in the magnolia trees, is not without its hazards.

As President Bush took a question Thursday in the White House Rose Garden about scandals involving his Attorney General, he remarked, "I've got confidence in Al Gonzales doin' the job."

Simultaneously, a sparrow flew overhead and left a splash on the President's sleeve, which Bush tried several times to wipe off.

No word on whether the on-the-sleeve incident can be successfully cleaned in the White House spin cycle.

Video here: http://abcnews.go.com/Video/playerIndex?id=3209176

Ron Paul: Rudy needs to read up

I just love the way Dr. No is making the GOP crazy:

"I'm giving Mr. Giuliani a reading assignment," the nine-term Texas congressman said as he stood behind a stack of books that included the report by the commission that examined the attacks on the United States on September 11, 2001. ...

"I don't think he's qualified to be president," Paul said of Giuliani. "If he was to read the book and report back to me and say, 'I've changed my mind,' I would reconsider."

Among the books on Paul's reading list were: "Dying to Win," which argues that suicide bombers only mobilize against an occupying force; "Blowback," which examines the unintended consequences of U.S. foreign policy; and the 9/11 Commission Report, which says that al Qaeda leader Osama bin Laden was angered by the presence of U.S. troops in Saudi Arabia. Another book on the list was "Imperial Hubris," whose author appeared at the press conference to offer support for Paul.

"Foreign policy is about protecting America," said author Michael Scheuer, who used to head the CIA's bin Laden unit. "Our foreign policy is doing the opposite."

A Giuliani campaign official could not confirm whether he had read any of the books on Paul's list.


Since an assortment of lunatics on the right fringe were incensed by Paul's insinuations after last week's Republican pukefest debate, I'll look forward to more sputtering indignation from over there in short order.

Why are there gravitons in string theory

Sean Carroll has written a text for Nude Socialist. It has an optimistic name
After I read the full text, it looks fair even though I am flabbergasted by the very observation that some people apparently think that physicists can suddenly change their opinions about theoretical physics because of a campaign organized mainly by two crackpots.

If an activist such as Al Gore organizes such a campaign in climate science, he can scare all sane people and everyone starts to twist the numbers and publish higher, catastrophic estimates of the future warming. It is hard to figure out that what the scientists produce is a biased pile of nonsense because every number a priori seems as good as every other number.




But in theoretical physics, this is simply not possible. If someone scares you into studying a theory of quantum gravity that differs from string theory, it simply won't work. Ingredients won't fit together. When you're ordered to work on such an inconsistent theory, you will feel like an idiot after you write down the second equation. Rightfully so. The whole machinery will collapse just like if you replace gasoline in your Chrysler by used toilet paper.

Gravity in string theory

But back to the main topic. Some people ask why string theory inevitably predicts spin 2 massless particles that moreover interact as gravitons.



Let me explain. Consider a closed string - a loop of energy - that oscillates in a spacetime. There exist functions
  • X^m (sigma,tau)
that describe the embedding of the two-dimensional worldsheet, a history of propagating string, in this spacetime. The laws controlling the oscillations may be described by a two-dimensional field theory defined on this worldsheet - a two-dimensional manifold with a spatial coordinate "sigma" along the string (X^m have periodic conditions in sigma, to make the string closed) and a temporal coordinate "tau".

Its equations of motion are essentially wave equations for the scalars X^m.

For every background geometry (and possibly other fields such as dilaton and gauge fields), there exists a two-dimensional action on the worldsheet. But only some geometries lead to a consistent string theory. In fact, the worldsheet theory must be invariant under conformal transformations - transformations of the worldsheet coordinates that preserve angles - because the internal geometry on the worldsheet and the choice of coordinates on the worldsheet must be unphysical: if they were not, we would introduce new, unwanted degrees of freedom (essentially new spacetime coordinates). Scaling is the most important conformal transformation.

How does the theory on the worldsheet change under scalings? A quantum field theory - and the theory on the worldsheet is an example - has various coupling constants. The change of a "running" coupling constant under scaling transformations is generally encoded in the so-called beta-function. For each coupling constant, you have one beta-function.



At the beginning, we mentioned that for every background geometry, we have one theory on the worldsheet. All numbers describing such a geometry, namely all components of the metric tensor
  • g_{mn} (X^k)
as functions of spacetime coordinates, are thus coupling constants of the theory on the worldsheet. How much do they run? What are the beta-functions? It is not hard to see that for every value of a component of the metric tensor, there will be one beta-function. Consequently, the beta-functions will depend on X^k and they will carry two vector indices. Moreover, they can be seen to include second spacetime derivatives of the metric tensor. When you think about the "manifest" spacetime diffeomorphism symmetry, it is not hard to see that the full answer for the beta-functions must actually be proportional to
  • R_{mn} (X^k).
If the worldsheet theory is consistent as a string theory, it must be scale-invariant, and the spacetime geometry must thus be Ricci-flat! We have just derived Einstein's equations from scale invariance of a two-dimensional theory. Or at least we have sketched the derivation. If we considered backgrounds with other fields (matter fields), they would also contribute to the beta-function. We would obtain Einstein's equations with the correct right-hand side.

State-operator correspondence

Strings can only propagate consistently on backgrounds that respect the laws of general relativity or its generalizations. Does it mean that there are gravitons? Yes, it does.

Take the worldsheet action for a particular spacetime geometry, and make an infinitesimal (epsilon) change of the spacetime geometry so that the geometry remains Ricci-flat (for example, add a gravitational wave). Look at the difference of these two actions (and divide by epsilon). In other words, differentiate the worldsheet action with respect to the spacetime metric. You will inevitably get another integral over the worldsheet coordinates:
  • integral d sigma d tau V(sigma,tau)
Any infinitesimal variation of the spacetime metric is thus associated with an operator V(sigma,tau) on the worldsheet. We can make something even more interesting. Cut a very small disk from the worldsheet. The new, short boundary of the worldsheet will look like a closed string. The actual length of this boundary is actually unphysical, because of the scaling symmetry of the worldsheet theory. For every wave functional on this closed string - a possible state in the Hilbert space of states of a single closed string - there will exist a local operator, and vice versa.

This one-to-one map is known as the state-operator correspondence.



Inserting the operator V(sigma,tau) at the point (sigma,tau) of the worldsheet is therefore equivalent to cutting a small disk around (sigma,tau) and integrating over all possible initial conditions on this circle weighted by an appropriate wave functional. For every local operator V(sigma,tau), there exists a state.

But previously, we have found an operator V(sigma,tau) for every possible infinitesimal variation of the background, e.g. for every gravitational wave. When we combine this old result with the most recent one, we see that for every gravitational wave, we discover one state of the closed string. In other words, closed strings will always have a state in their Hilbert space that is canonically associated with a change of the spacetime geometry.

Because closed strings in the Minkowski space - the simplest example (that approximates very well any background whose radius of curvature is much longer than the string scale, a typical distance scale associated with string theory) - are really described by a pile of ordinary harmonic oscillators, it is not hard to see that the states associated with the operators V(sigma,tau) corresponding to an infinitesimal perturbation of the spacetime geometry are spin 2 particles.

The operator V(sigma,tau) for a gravitational wave looks like
  • exp(i k.X(sigma,tau)) partial_+ X^m(sigma,tau) partial_- X^n(sigma,tau)
It depends on a spacetime momentum vector "k". The complex exponential is multiplied by a holomorphic derivative of one "X" and the anti-holomorphic derivative of another "X". The two free indices "m,n" give it a spin equal to two.

Do the corresponding particles - closed strings with a particular vibration on them - interact as gravitons? You bet. When you deduce the interaction rates among these spin 2 particles composed of a vibrating closed string, the state-operator correspondence guarantees that they will respect the overall equations of motion given by Ricci-flatness - a condition that we have derived from the conformal symmetry.

There are other ways to see that the interactions of the string-theoretical gravitons must exactly respect the rules of general relativity. Every consistent gauge-invariant theory of spin 2 massless particles must inevitably have the diffeomorphism symmetry built in it which essentially guarantees that the theory is a version of general relativity.

You can indeed check that the spin 2 particles obtained from the vibrating closed strings are massless, gauge-invariant, and their interactions are consistent. That assures that the scattering amplitudes will coincide with those obtained from general relativity (in the long distance limit). You may also verify this conclusion by explicit calculations.

AdS/CFT

There are other approaches to string theory that have been shown to describe the same laws of physics. Holography in anti de Sitter spaces is a popular example. In this picture, there is a non-gravitational theory defined on the boundary of the anti de Sitter space at infinity and the key statement is that this theory is equivalent to a theory in the bulk.

The bulk theory is inevitably a gravitational theory. In other words, it is a consistent theory of quantum gravity, also known as string/M-theory. How can you see that there must always be gravity in the AdS bulk?

Well, the reasons are somewhat similar to the worldsheet arguments above. A particle that can go to the boundary of the AdS space corresponds to a local operator on the boundary. In this case, we are interested in the stress-energy tensor on the boundary, a rather special kind of a local operator. For every component of the stress-energy tensor of the boundary theory, there must exist a physical particle in the bulk. Once again, one can prove that the interactions of these particles must be consistent with the diffeomorphism symmetry: they must be gravitons.

There are other reasons why the bulk theory is always a gravitational theory. In non-gravitational theories, the entropy stored in a volume V is proportional to the volume. In gravitational theories, however, the maximum entropy you can squeeze into this volume is carried by a black hole and the black hole entropy is only proportional to the surface area. Gravitational theories secretly carry a small number of degrees of freedom than what you would naively think. This is a key fact that makes holography possible.

Matrix theory

In the BFSS Matrix theory, only highly supersymmetric backgrounds are well-understood. The origin of gravitons in any Matrix theory is always analogous to the case of the maximally supersymmetric, 11-dimensional background of M-theory.

If you have 32 supercharges, you can prove that there are states that preserve one half of the supercharges, namely 16. The broken generators can be combined into 8 complex pairs - 8 creation plus 8 annihilation operators in a fermionic harmonic oscillator. Each such an operator raises or lowers the spin by 1/2. They're exactly enough to climb from
  • j_z = -2 ... to ... j_z = +2
because there are (+2 - (-2)) / (1/2) = 8 steps in between. 32 supercharges thus guarantee, once again, that the spin j=2 is the highest spin included in the simplest supermultiplet. Supersymmetry - one of the symmetries that can also be proven in Matrix theory - also implies that general relativity must be included in the effective action, by spacetime arguments.

There are other approaches to string/M-theory that can be proven to describe the same local physics in spacetime. In all cases, one can also explicitly show that the graviton is a part of the story. The methods to find the gravitons that we sketched above look very diverse but in overlapping situations, they are related.

Wednesday, May 23, 2007

A reply to Gina

Unsuccessfully linked elsewhere: Falsifiability in physics (direct link here)
Gina is one of the more sensible participants of the laymen's discussions about string theory. While the majority of others who think that Smolin's and Woit's comments make any sense are deeply confused people incapable of a rational manipulation with ideas related to theoretical physics, Gina at least sometimes tries to use his or her brain a little bit.

As we can see in this new text, this positive appraisal certainly doesn't hold universally.

Weakest link

Joe writes that a chain of reasoning is only as strong as its weakest link. You would think: what an obvious fact. Gina conjectures that there are cases when it's not true because the weakest links are strengthened by the stronger links. Well, I happen to think that if this occurs, we can be pretty sure that the person is doing something very different from a rational analysis.

Many links can make a lot of sense but if a whole argument depends on a link that cannot be replaced by another link and if this link is weak, the whole argument is weak, too. I simply can't imagine how a rational person could ever disagree with this fact. Weak links can only be ignored if there are other links that can be substituted instead of them into the logical chain and that can play their role, either completely or at least partially.

Gina also writes:
  • Certainly Joe’s line is not so positive when it comes to string theory. Some of the links (or steps) are not only weak but yet non-existing.
Well, I think that this pair of sentences is thoroughly incompatible with a scientific mode of thinking. There are two basic problems with these sentences:
  • It is not explained what statements are actually being discussed in these sentences: "string theory" is not a statement
  • The statements are really untrue as long as the actual subject is any important and generally accepted well-known insight of string theory: how can someone be so "certain" about a statement that is demonstrably incorrect?
Let me explain a little bit. If science is done properly, we don't reduce all questions to the question "string theory Yes/No" that would be discussed with the help of oversimplified sociological pseudo-arguments: physicists leave this job to the crackpots and journalists.

Instead, physicists are talking about much more concrete, less ambitious questions that can actually be grasped and studied by the scientific method. It is nice if someone is ambitious but if he can't find any chain with strong links that makes any sense, the ambitions are useless or worse.

In junk sciences, things are very different. For example, the "climate change science" tries to transform every observation to an argument showing that "global warming is true", and the statement "global warming is true" is then used to justify any favorite assertion or policy of the people who like this particular junk science.

The similarity with God - something that always sits at the center of all arguments - is obvious. This new kind of God always plays a role in any system of ideas that the climate change "scientists" and their fans produce. Moreover, the links between this new kind of God and the actual observations or predictions are usually weak and sometimes they are upside-down.

But high-energy physics is not another junk science. High-energy physicists actually talk about concrete chains of arguments and facts and their relationships - relationships that usually circumvent the "big questions" and God - and they must very carefully realize that the chain is as weak as its weakest link. It is much more reasonable to connect two things by a chain if these two things are close to one another in which case the chain can often be extremely strong: we don't need to connect A and B by a long chain from A to God to B. When these things are done properly, we can demonstrate things like
  • local quantum field theories of the known types can't lead to a predictive theory of quantum gravity at the Planck scale
  • black holes inevitably have thermodynamic properties such as entropy and temperature
  • string theory is finite to all orders of perturbation theory and probably beyond
  • huge classes of theories at a comparable level of complexity as string theory are much less consistent than string theory
  • a conformal field theory is equivalent to stringy quantum gravity in the anti de Sitter bulk
  • experimentally established physics of gauge theories is connected with - in fact, equivalent to - gravitational physics in higher-dimensional spacetime that includes stringy phenomena
  • vacua of string theory are connected
and thousands of others in such a way that all links are strong. Whoever thinks that the physicists are so stupid that they are consciously using chains where links are weak has been manipulated by factories producing fog and lies such as Peter Woit and Lee Smolin. Their statements are simply not true and every good theoretical physics grad student knows why.

The fact that many people repeat Woit's and Smolin's stupidities doesn't make these stupidities less stupid. The fact that it has become fashionable in certain communities to say these things doesn't make them intelligent either. Whoever repeats all these silly comments about divergences of string theory, doubts about Maldacena's duality, comments about the heresy of believing a large number of solutions to the fundamental equations of quantum gravity, or speculations about a hypothetical weakness of the string-theoretical picture in general is just an overly simple-minded person whom I assertively encourage to realize his or her severe intellectual limitations.

The weakest link in the string-theoretical image of the world is a direct experimental evidence. Everyone realizes that this is a weak link. It is not easy to get experimental data about quantum gravity. This unsurprising fact is a real difficulty for everyone who actually tries to think about these things and find answers, as opposed to a "critic" who only wants to spread hatred and lies.

No string theorist would dispute that the absence of a direct experimental proof is one of the weakest links in the chain of reasoning that leads us to think that string theory describes the real world at the most fundamental level. It is probably the weakest one. One can try to replace this weakest link by other, more theoretically flavored links, but everyone knows that the replacement is not perfect.

It is extremely important to realize and acknowledge what the weak links actually are. It is extremely important not to hide weak links. It is however equally important not to create the impression that some additional weak links exist if they don't. It is illegitimate to spread lies about weak links, even in the context when you make loads of dopes happy by spreading these lies.

Maldacena's duality

Gina tells us that he or she sees nothing wrong with a research program aimed to find weak points in or counter arguments to the strong Maldacena’s conjectures. Well, there are only three wrong things about this research program:
  • this research program is demonstrably wrong because it contradicts things that have been established by careful analyses
  • the very motivation of the research program is biased
  • there is nothing such as strong and weak Maldacena's correspondence.
Whoever tries to think that there simply must exist weak links of the AdS/CFT correspondence and is not ready to change his or her opinion even when robust calculations show that the whole duality is unbreakable is a bigot. Moreover, the very approach trying to selectively look for weak links shows a prejudice of the researcher. The scientific community - and in most cases even individual scientists - should try to find out whether a statement is true instead of selectively trying to look for negative or positive arguments only. Gina's recommendation is just another example of a lack of scientific integrity. It is shocking if he or she doesn't realize that.

Needless to say, when things are done properly, we can see that there exist no weak links in the chain of reasoning that leads to the AdS/CFT correspondence, at least in the backgrounds that have been widely studied such as the N=4 gauge theory in four dimensions. Indeed, to falsify Maldacena's duality, it would be enough to find one calculation that would demonstrate that the AdS/CFT correspondence doesn't work. No such calculation exists.

Gina claims that Polchinski has argued that finding errors in a duality is a priori misguided. Polchinski has never claimed so. It is misguided to be looking for errors in "strong" Maldacena's correspondence and it is misguided to talk about "weak" Maldacena's correspondence but it is only misguided a posteriori, after the checks have been carefully made in thousands of papers, checks that imply that no such weak links exist and no available definition of a "weak" Maldacena's correspondence can survive a scrutiny.

Temptation of rigor

Gina shows us that he or she has completely misunderstood the facts about rigor being useless or worse when the assumptions are physically wrong. He or she asks:
  • If there are scientific reasons to reject the argument based on “Rehren duality” that is fine, but what does it have to do with rigor in general?
Well, the reason why these two questions are closely related is that Lee Smolin, among many others, is trying to oversell physically meaningless constructions such as the Rehren duality by claiming that the Rehren duality is "rigorous". It may be rigorous but from a physics viewpoint, it is a naive tautology about non-holographic theories, a tautology that has nothing to do with the actual non-trivial content of holography in quantum gravity. Joe only gives his explanations because he has finally noticed that some people misunderstand that by formulating some ideas in a "rigorous" framework, they don't become physically valid.

As our understanding of the laws of physics expands, we are becoming more familiar with the importance of different characteristics of scientific hypotheses. We learn which characteristics eventually decide about the validity and consistency of a physical hypothesis or a framework, and which characteristics are superficial and physically irrelevant clothes.

The Rehren approach is an approach that tries to be careful about superficial characteristics that are physically irrelevant - the approach cares about the shape of the wooden earphones that you know from the cargo cult sciences - while it completely ignores the things that are essential for physical theories. The standard particle physics and string theory approach is the opposite one.
  • But, in my opinion, it does not come across very well when (even justified) weaknesses are portrayed as advantages.
No one has ever claimed that a weakness is an advantage. Joe has just explained the obvious fact that having the Rehren style of rigor is not a physical advantage because it is not. And the lack of the Rehren style of rigor is not a physical disadvantage. The actual physical arguments ultimately boil down to an indirect analysis of observations and after the dust is settled, they imply that Maldacena's duality is profound and true while the Rehren duality is a vacuous and silly tautology. The validity of physical theories has nothing to do with the beauty of the fonts in which the equations are written or with the Rehren style of rigor.

Retractions

Gina is surprised that we hardly see any retractions - statements like "I was wrong on this point". Well, Lee Smolin has had more than 25 years to understand why his ideas from 100+ of his mutually incompatible papers are wrong and make these retractions because many leading figures whom I know as well as many other physicists such as your humble correspondent have spent quite a lot of time with explaining him his mistakes in detail.

I fear that if he hasn't listened to rational arguments for more than 25 years (or if he has never remembered the discussions after they ended), he will never do so. Physicists who understand their science probably won't think that Lee's comments and papers make many sense but millions of confused laymen and thousands of journalists will and that is apparently what Lee Smolin really cares about.

And that's the memo.