Lehman Brothers

As a general rule I want to preserve this blog for talk about physics but several of the well read physics blogs are talking about the banking crisis and the collapse of Lehman Brothers so I will make one comment here. I am not going to say anything about whether governments should be bailing out banks. I am looking at the longer term issue of why this kind of thing happens.

Let’s get one thing out of the way. The situation is nothing to do with how quants model prices and invent new types of security. There are many types of risk when you take on a financial contract and models such as Black Sholes only take a few short term risks into account. It is well known from experience that hedge funds will collapse due to liquidity risks of you take the models too seriously. The only way to prevent it is through the application of common sense and experience.

Lehman Brothers narrowly escaped from going under in 1998 when it was hit by a combination of an Asian financial crisis, the collapse of junk bonds in emerging markets and exposure to the failed LTCM hedge fund. Why did they not learn from this? This time round they were hit by a crisis in the US mortgage market. Lehman Brothers were very big on mortgages and had huge assets in risky sub-prime loans. Low interest rates had allowed the banks to inflate the housing bubble without it bursting for too long, but it was inevitable that it would burst soon. Why could they not see such an obvious risk?

The answer of course was that they could see the risk. They may not have expected the end ot be quite so dramatic but they knew the market as well as anybody. Predicting exactly when a financial bubble will burst is like trying to predict when a good spell of Autumn whether will end. There is no formula for it. But it is easy to see that it must end at some point and it may end with a dramatic storm.

To understand why they did nothing you must look at the structure of an investment banks workforce. Most people in an investment bank are paid well but there is a small minority who are paid extremely well. They are the MDs and above. They constitute perhaps 1% of the total workforce yet they get the majority of the pay and most of that comes in the form of an annual bonus. They are paid on the basis of how much money they and their staff can make the bank each year. Many MDs count their bonuses in millions of dollars. By time they get to such a high position they have probably already earned enough to be able to retire in comfort for the rest of their lives. Few of them work in a bank because they like the lifestyle. They are there to earn as much as they can as quickly as they can before they move on. In such a system it makes sense on a personal level to take high risks in the hope of making a lot of money in a few years. When they do well they get a big bonus but when they fail and the bank looses money they do not have to pay it back. Usually they will calmly announce their departure well before the end of the year knowing that big bonuses are not due. They may move on to another bank where they will be welcomed with a huge golden hello to compensate them for their loss of tied shares, or they may just retire to their ranch in the South.

Given such a system of remuneration it is a wonder that banks do not go under more often, but there are forces that keep the risks down. In the short term risks are controlled with suitable hedging. Many financial instruments devised by quants are designed for this purpose. If you have exposure to a company that would mean a loss if it went bust then you can buy a credit default swap that pays out like insurance when that happens. Another factor that keeps risks down is regulation. Government operated regulators stipulate that banks must keep sufficient capital in liquid low risk forms such as cash so that they are financially sound, but these regulations have to be spelt out as rules and formulae. They cannot be left to common sense, yet as I already said, an element of common sense and experience is required to judge the largest risks.

There is one more factor that helps keep risk down. It’s the banks ratings. rating agencies such as Moody’s, S&P and Fitch provide credit ratings for companies, governments and other agencies that issue bonds. Governments have the highest AAA ratings when they sell debt in their own currency because they can always print more money to pay the coupons. Large banks are often the next highest. The rating agencies gauge the rating of the bank based on their performance and on the type of assets they hold. If they see that they are taking too high a risk they should lower the rating. These ratings are very important to the bank because their cost of borrowing is directly linked to them. Just like an individual person it is easier and cheaper for a bank to borrow money if they have a good credit rating. Banks need to borrow money to invest in assets and ventures that return a higher yield. The ability of an investment bank to make money is directly related to its credit rating. Nothing is more important to the bank. The ratings are intended to measure the long term security of the company because they often support bonds issued for 30 years or more, so it is these ratings that force the banks to care about their long term risks.

So the rating agencies have a controlling hand in Wall Street, yet they are not government controlled. They are public profit making companies. Somehow they failed to see the huge risk that the banks had taken with mortgage backed securities. When the dust settles and people start to seriously investigate what went wrong, the big question will be, Why did the ratings not reflect the risks the banks faced?

Today Wall Street has undergone a dramatic change. Lehman Brothers are gone, Merril Lynch has been acquired by BOA. Goldman Sachs and Morgan Stanley have given up their investment bank status. There is not much left of the system that ruled a few months ago. But in time they will return. The US treasury will release the grip it has been forced to take and the money making machine will move back into the hands of the MDs. Investment banks are needed to finance the economy and politicians are notthe right kind of people to run them. Human nature cannot be changed so history will be in danger of repeating itself, but the world needs a stable economy. It does not need a cyclic economy that falls flat on its face every 10 years.

Solutions: Governments buying back bad debt is a short term solution and not one they will want to repeat. The bonus system for renumeration in banks is partly to blame for the problem but it is driven by market forces so it is hard to eliminate. Monitoring individual bonus awards is not practical in the long term although a few measures such as outlawing golden hellos which compensate loss of CSA would help.

The only practical long term solution is for governments to set up their own impartial rating agencies for banks and other large institutions who issue debt or act as counterparties in financial transactions. These agencies would have to be harsh by reducing ratings when a bank takes on too much risk, especially liquidity risks. To make the process less painful they could use a more fine grained rating that can be raised and lowered in smaller increments. They could even include the effect of the companies bonus policy in the equation. Traders would be quick to factor the ratings into their pricing just as they do now with the ratings from Moodys and S&P to take account of counterparty risk. The effect would be more immediate and dramatic than any artificial process of sanction or taxation.

LHC roundup

Today CERN took a huge risk with the media by transmitting the LHC first beam live to the world. They may not have expected so much interest but the controversy about imagined dangers brought it to the worlds attention. Physicists are not used to such exposure and it must have put a lot of pressure on the engineers controlling the operations today.  

It could have backfired if they had to delay the start for technical reasons but that was not allowed to happen. Instead we were treated to an exciting day watching the experiment start up and proceed much better than expected. When the days goal of circulating a beam one way was achieved within an hour, Lyn Evans ordered an attempt on the contercirculating beam for the afternoon. It nearly went wrong when some problems with the magnets slowed down progress but some tuning was enough to fix it.

I dont know how many people watched the events live as I did but with not much else happening in the news it is making top billing on many news broadcasts. For once people have seen physicists as real people doing an exciting job showing international cooperation and great expertise. There should be a lot of followup interest from people wanting to understand more and hear of the results.

It was good that this was publicised because people have paid for it and deserved to know what was going on. I wonder how many young physicists in ten years time will cite this as the defining moment when they wanted to become a scientist.

Well done to all the CERN teams!

LHC live

It is 8:56 in London and the beam has now gone half way round the collider to applause from the control room. So far they have progressed faster than expected. Carlo Rubbia (Fromer director of CERN and Nobel prize winner for discovery of W) can be seen in the crowd.

9:00 The beam has been seen in CMS and Alice. CMS has seen tracks. Now they are going for next shot…

9:02 They are very excited by how fast they have been able to get to this stage. The champagne bottles are already open with the beam 60% of the way round. They now hope to do a full trip round the beam in th next half hour. That was the target for today. then they have to make it go in the other direction.

9:12 Another light round of applause. Looks like they are about three quarters of the way round.

9:16 even google are in the act..

9:17 another run nearly all round..

9:19 the guy directing the proceedings is Lyn Evans from the Cynon Valley town of Aberdare

9:20 Only Atlas has not yet seen the beam

9:23 Atlas has seen the beam. They are romoving the last block and will start the next cycle in one minute to go all the way round

9:25: cheers and applause. The run worked. In fact they made two round trips.

9:30: the bbc news 24 has stopped reports for now.

Large Hadron Collider FAQ

The LHC is scheduled to start up in 23 minutes (It is 8:17 London time)  and with little else news around it is top headline news here in the UK. The BBC is getting ready to cover the event and has just past on the news that CERN has reported some “small electrical probelms” that could cause delay. I am not expecting anything spectacular to happen today but am following the news to see if the BBC has learnt how to pronouce “Hadron Collider” today. Yesterday they mispronounced both words ha ha. I would be watching this on the CERN live web feed but as predicted it is not working dur to heavy load.

OK so here is a quick FAQ while we wait

Why is this happening?  They are running this experiment purely to know how the universe works. Our current theories of physics can explain everything we see on Earth and most of the universe but there are gaps in our knowledge. For example we do not know what dark matter consists of. The LHC may answer that question and others.

Will the LHC destroy the Earth? No, the collisions being created in the collider happen all the time in the Earth’s atmosphere and all around the universe. If there were dangers we would already have encountered them in  nature. The theory that the LHC could create blackholes is very speculative and is one of the least likely things to happen and even if it did the black holes would evaporate very quickly and do no harm.

What will be the practical benefits (given that it cost billions)? No direct benefits are expected and it is even unlikely that there will be any unexpected ones from the physics at least within current lifetimes. However the technology used to build the collider pushes boundaries in the same way as the space program does. The money spent creates high tech jobs and the expertise gained helps progress technology and world economies. There are also educational benefits because it helps get people interested in physics. Other unexpected benefits do appear. The World Wide Web was invented in CERN and is regarded as one of them.

What will the LHC find? If we knew the answer to that we would not have to do it, however there are some theories. The LHC is expected to find the Higgs boson which accounts for the mass of particles like the electron. It may also find supersymmetric particles and who knows what else.

When will these discoveries be made? Well not today. First there will be tests and a series of callibration runs that could last months. The collider will be shut down and restarted next year. It will probably not be until then that useful data will be taken. It could then take years of runs to collect enough data to show where the Higgs is. It is possible that supersymmetry could show up quite fast..

Newsflash: after a five second countdown the first beam started and went 1/8 of the way round. They are now going to tune some magnets, remove some blocks and try to go further. They say it could be another couple of hours before they do the full tour.

… but even if it does it will take months to analyse the data well enough to publish the results. The teams of experimenters will be expected to keep results secret until the analysis has been done but with so many people involved we would expect some leaks eh?

Update: There has been another run which wenrt 10 km. It has reached the CMS detector. It is now 8:47 in UK

Big Bang Day

Wednesday the 10th September is now “Big Bang Day” in the UK. It is of course the day when the LHC gets turned on and there will be coverage by the BBC on radio 4. Nothing is scheduled for TV which indicates a profound lack of interest from the public and media. That has not stopped the tabloids trying to drum up some interest by highlighting the claims that the experiment will destroy the Earth. Despite the British public’s profound distrust of scientists this storyline seems to be failing to pique the imagination of the anti-science lobby. As far as I know there will be no protests or overnight vigils outside parliament. Perhaps the papers should have directed people to the lecture by Jon Ellis on LHC safety. The site of a stereotyped mad scientist with a bushy white beard and scary teeshirt instructing a sniggering audience of younger boffins so that they can go out and reassure the public would be sure to sound the alarm loudly.

Yesterday evening we were treated to a couple of hours of programs about the big bang and the LHC on BBC 4. As far as I can tell there is nothing else about it on TV but I have not ploughed through all the TV listings for the next week so maybe I missed something. The best place to follow what is going on is probably the CERN website where they prefer to call the event ”LHC first beam”. They will have live webcasts using the same technology that they used for “strings 2008″ a couple of weeks ago. I don’t know if it was just me but I did not find those webcasts ran smoothly and I suspect there may be more interest in this event. So I am not optimistic that it is going to work well. There will be some FTA satellite feeds but I dumped my steerable dish some time ago so that option is blown.

Loop Quantum Gravity and String Theory

In the early days of Loop Quantum Gravity there were people who expressed a hope that ideas from LQG could be applied to string theory in order to provide the background independent formulation that people were looking for. It was a natural idea because we knew that string theory lacked a formulation that was non-perturbative and diffeomorphism invariant. LQG is constructed in a way that respects the general relativistic structure of spacetime but it fails to provide the right classical limit with gravity. The failing of one theory were the strengths of the other so perhaps a mergence of the two would solve everything

It seemed like there were good reasons to believe that LQG and string theory could be brought together  because they both had origins in loop models of gauge theory. In three dimensional gravity string theory and LQG could be viewed as different views of the same model. This just had to be extended to higher dimensions.

Lee Smolin, one of the founders of LQG, responded by learning string theory and trying to reformulate it in LQG terms, but string theorists were not impressed. I don’t think you can generalise the point of view of every string theorists but the open secret passed around was that LQG was a wrong lead. Physicists working on LQG were actually proud of the fact that it worked only in four dimensions and that it worked without including matter, (except that it didn’t actually work). To string theorists these ideas were simply out of date. There were even mad people who thought that the loops in LQG could be he same thing as strings and that was plain crazy. Every string theorist knows that strings can pass cleanly through themselves and each other without restriction while knotted loops can’t.

Over time the split between LQG and string theory grew stronger. It was aided by the politcal need to divide research into separate disciplines for the purposes of funding. With most people working on string theory, LQG had to be characterised as an alternative approach to be funded separately. Smolin abandoned his attempt to apply LQG methods to string theory and instead wrote his infamous book “The Trouble with Physics: The Rise of String Theory, the Fall of a Science and What Comes Next” . His followers went with him and the wedge between LQG and string theory moved further in.

So what is the reality? Could LQG tell us anything about string theory? Well first of all the fact that LQG has not worked on its own does not mean that it can’t be applied to string theory. Perhaps it can only work when the right matter fields are included in the right way. The knotty mathematics of LQG is related to quantum groups which also make an appearance in the conformal field theories used by string theorists so perhaps the two approaches are not so distant.  But what of the argument that strings are not like knots because they pass through without hindrance? Actually this is not how things really are. When a string passes through itself it may pass unhindered or it may interact with itself at the crossing point causing it to split into two separate strings. The resulting interaction looks just like the Skein relations used in the mathematics of knot invariants. Other relations in spin networks related to associativity can be connected to crossing symmetry of the string theory S-matrix. In fact the list of connections between LQG and string theory is endless once you start looking for them.

At this year’s string conference David Gross renewed the call to find out what string theory is and how it should be formulated correctly. So why doesn’t someone just apply LQG quantisation to string theory and solve the problem? Gross and other string theorists are quick to dismiss LQG, so does that stop other smart people trying? I think the real problem is that there is a genuine mathematical gap between LQG and string theory that is hard to bridge. LQG relies on a special property of 4-dimensional spacetime that allows gravity to be reformulated in a way that succumbs to quantization. The same trick cannot be applied to the higher dimensional supersymmetric spacetimes in String Theory.

Yet there is still hope. There are hints of relationships between supersymmetry in 3,4,6 and 10 dimensions and the division algebras R, C, H and O. Perhaps if the complex based quantum mechanics of LQG could be replaced with quaternionic or octonionic quantum mechanics it would work in 6 and 10 dimensions. Who knows?

A string theorist recently said in his blog that you have to look at the equations and discover the solution rather than inventing new theories. In string theory this approach has been a very successful way of discovering cross-dimensional dualities and other unexpected phenmena like holography. As they are fond of saying around here “you couldn’t make it up”. But LQG was also ”discovered” by quantising gravity in a particular way. Like string theory it was not invented, so it also has a special power to show us new things.

For the moment everybody is stuck. I think the situation is stalled because of a lack of vision that blinds people to the mathematical relationships they need to be thinking about. Perhaps something observed in the LHC will provide a new light that shows the way forward, or perhaps the inspiration will come from someone else who steps back and sees the big picture. Community attitudes may fog our view but it will only require one person with vision to see the way. Let’s hope we dont have to wait too long.

Large Hadron Collider

Tests of the LHC at CERN have now been completed and final preparations are underway to start running in just two weeks. Collision energies will ramp up to 14TeV (centre of mass) by the end of the year before further adjustments are made to bring the energies up to 20TeV next year.

So this is a good moment to think about why the LHC is so exciting for theoretical particle physics. For the last few decades collider experiments have gradually built up in energy and have found many new particles along the way, the W, Z, bottom, top etc. It has been exciting for the experimentalists and some of them have even come away with Nobel prizes, but for the theorists it has been a bit underwhelming. The problem is that all the particles seen were predicted as part of the standard model 40 years ago and nothing that is definitely outside it has been observed. Only parameters such as masses and decay rates were not predicted and had to be determined by these experiments.

The main task of the LHC is to find the Higgs Boson, the last of the particles predicted by the standard model and not yet seen. The Higgs boson is unlike any fundamental particle seen before because it has spin zero. All fundamental constituents of observed particles have either spin half (quarks, leptons and neutrinos) or spin one (photons and other gauge bosons). So if the standard models is correct the Higgs boson will be a unique discovery. Yet it is still a particle predicted in the 1960s and its discovery will be a dissapointment if it is not accompanied by something else a bit more special.

What makes the LHC so exciting is that there is a strong optimism that something more special willbe found. We know that the standard model cannot stand alone in particle physics. According to phenomenology the Higgs particle would be lost is a blizzard of radiative corrections if it were alone. It can only survive if there it is accompanied by a fermion of nearly equal mass. This fermion known as the Higgsino would have to have its own corresponding interactions to match those of the Higgs. In fact there would have to be a whole load of other partner particles for each of the known particles in the standard model which would be similar but heavier. These partners are called superpartners and the simplest model that includes them is the Minimal Supersymmetric Standard Model, or MSSM. If the MSSM is correct then the Higgsino and some of the other superpartners will also be seen at the LHC, and if it is not correct then something different must take its place.

There are other good reasons to expect to see the MSSM. Supersymmetry can explain the hierarchy problem, and its corrections to the running coupling constants bring them together simultaneously at the GUT scale. There is also hope that one supersymmetric particle should be stabilised by a feature of the MSSM called  R-symmetry and a heavy particle of that sort is needed to explain the existence of dark matter.

Is there a danger that the MSSM is such a certain prediction that its discovery will have little impact on theoretical physics? Maybe but probably not. Supersymmetry in the MSSM is broken, otherwise all particles would have the same mass as their superpartners and would already have been seen. The MSSM does not include a specific mechanism for the symmetry breaking so it has a couple of hundred independently undetermined parameters. There are many constraints on these parameters which are needed to make the model consistent with the lack of flavour changing currents and CP violation at low energies, but apart from that we have very little understanding of how the model works. Once we start to study it we may start to see more clearly what the mechanism for supersymmetry breaking is, and then we would have an idea what unbroken supersymmetry would be like at high energies.

What we really want to find is that supersymmetry is a gauge symmetry with a dynamical symmetry breaking mechanism related to the one that breaks the gauge groups in the standard model. That would be exciting because supersymmetry as a gauge group can be a spacetime symmetry as well as an internal gauge invariance. That means it could include gravity and unify it with the other forces. There is no guarantee that this will happen. The supersymmetry in the MSSM could just be an approximate global symmetry like the one between different flavours of quark, or it could be an internal gauge symmetry that does not include gravity. But at some scale something must happen to reduce the large parameter space of possible models and stop the endless trail of anomalies that are thrown up.

It would be going too far out on a limb to say that supersymmetry will tell us if superstring theory is correct. String theory itself seems to predict that the connection between low energy physics and superstrings is lost in the landscape of possible superstring vacuums and we have no right to expect a superstring signature at collider energies. Of course the observation of large extra dimensions at the LHC has been slated as a possibility but it is not a certain prediction of superstring theory and is not a serious expectation.

Nonetheless, if observations of supersymmetry can be used to make a case for supergravity as a superunification, then superstrings are not far away. Cancellation of anomalies in supergravity have been seen to be better than even the supersymmetry can account for. Its good behavior is best explained by the fact that it is a limit point of superstring theory. Indeed the structure of supergravity theories in high dimensions are so close to those in superstrings that it seems unnatural to have one without the other. So supersymmetry at the LHC would not itself be strong evidence for superstrings but it would be a big step in the right direction. After we have taken that step we will know how much further we can see from there. 

What else can we expect at the LHC? I don’t know, but one thing I do not expect is black holes. Back holes belong to the realms of energies well above the Plank scale. Anything that is theoretically a black hole below the Plank scale would in fact just be an ordinary particle. Light black holes have no properties to distinguish them from interacting particles. They are not black and they do not swallow up mass. It baffles me that some people talk about the production of black holes at the LHC. I can’t see the sense in it.

Could there be something else unexpected to be found at the LHC? Yes of course. A new particle of high mass does not leave much signature at lower energies, you only find them when you probe with a big enough acceleraor. But new particles and interactions could happen at any scale and for several decades all new fundamental particles were already predicted before discovery. It was only in the early days of experimental particle physics that new entities such as the muon could take us completely by surprise. The LHC is exciting because it reaches the scale of electroweak unification where we expect something special, but we have a good idea what it should look like. The most likely scenario is the emergence of the MSSM with nothing else new. That should be exciting enough.

Lesson 4: The Quantum Necklace

Its time for another string theory lesson yipee! We are building up to quantizing the superstring in small steps and the next stpe is going to be to quantize an ordinary non-relativistic closed free string like the one we looked at in lesson 1.

To make things more interesting we are going to discretise the string so that it is made up of N classical particles each of mass M/N. We can get back the continuous string of mass M by taking the N → ∞ limit. A discretised string like this is called a necklace for obvious metaphorical reasons.  

The beads on our necklace are held together with little springs that join neighbors. The tension increases in proportion to how much they are stretched with coeeficient of elasticity EN so the potential energy in each spring is proportional to the square of the spring length. Let’s write the position of the i^th bead (i = 1,…, N) as x_i  and the momentum p_i, then the total Energy of the system is

H = Σ ½ (M/N) [(d/dt)x_i]²  + Σ ½ (EN)(x_i – x_i-1)²

with cyclic boundary condition. The renormalisation of the mass and coefficient of elasticity are chosen so that the energy terms have a finite limit as N goes to infinity for a fixed string path.

This equations of motion  are of course linear and can be diagonalised using a discrete fourier transform

x_l  = Σ a_j e^{2πi jl/N}    summed over j = 0, … , N-1   with a_N-j = a_j^*

The energy transforms to a collection of independent harmonic oscillators (and one free mode for j=0)

        H = Σ ½ M |(d/dt)a_j|²  + Σ ½ EN² sin(πij/N)|a_j|²

These can be quantised in the usual way amd the infinite N limit can be taken so long as you don’t try to calculate the total energy.

One reason for looking at the necklace is the matter of the statistics on the beads. In most quantum mechanical systems of many particles the hamiltonian is invariant under permutations of the particles. It is usually reasoned that the multi-particle wave function Ψ(x₁,…,x_N) must reflect this symmetry by either being synnetric or antisymmetric

Ψ(x₁,x₂,…,x_N)  = ±Ψ(x₂,x₁,…,x_N)  etc

The two dfferent possibilities determine whther we are dealing with bosons or fermions and determine how the system should be second quantised. With a necklace the logic breaks down from the start because the hamiltonian is not invariant under permuatuions of the particles. It is only invariant under cycles which could lead us to impose cyclic constraints such as

Ψ(x₁,x₂…,x_N)  = exp(2pik/N) Ψ(x₂,…,x_N,x₁)

for some integer k. The question is, how should this affect the way we do second quantisation for string field theory?

Dirac Medal 2008

Congratulations to Maldacena, Polchinski amd Vafa on their award of this years  Dirac Medal. The medal is awarded each year by the Abdus Salam International Centre for Theoretical Physics which is based in Italy. This years winners were acknowledged for their contributions to string theory.

The past winners list includes many other outstanding contributors to string theory such as Witten, Nambu, Polyakov, Gross, Schwarz and Green. I think that is very appropriate because Dirac himself was the first to investigate strings and membranes as alternatives to particles. The prize cannot be given to anyone who already has an award from Nobel, Fields or Wolf . It is great the theorists whose work is not likely to qualify for those but there are a few cases of people getting these prizes later.

I can’t help noticing at least one surprising omission from the list of winners, namely Lennard Susskind whose book I recently reviewed here. He is recognised as one of the founders of string theory and has made several other major contributions such as work on the holographic principle and the landscape. He has also made very significant advances in particle physics outside string theory. I wonder why he has never been handed a Dirac Medal. He does not have any of the three excluder prices. He does have the Sakurai prize but other winners of that have subsequently won the Dirac medal so it does not count against. Susskind has been quoted as saying that he would “refuse any prize for advancing the so called convergence between science and religion”, but surely that does not apply to the Dirac Medal.

I think the omission and refusal of awards is much more interesting than their giving. For example did you know that Hawking refused a knighthood? That’s fantastic, nice one Stephen. On principal I would never refuse a prize that included me getting lots of money, but pure honours are a bit crass.

Book Review: The Black Hole War

Mostly my reading material consists of papers, text books and fiction, but sometimes I can also appreciate the odd popular science book. However it needs to be a book written by someone who is an active expert in the field. If it is written by someone who just follows the science with no big contributions of their own then It will probably just go over stuff I am familiar with, especially if it is about physics. What I like to see in these books are historical accounts of how an idea developed and any speculative insights that the author is willing to give away for the future. I tend to skip the sections and chapters that just try to explain the basics in layman’s terms so if that is all that’s in the book I wont read it.  

Most active experts dont stop to write popular books unless they have a Nobel prize, then it becomes obligatory. Perhaps that is why there have been so few pop science books about string theory by the people who made the biggest contributions. Lenny Susskind is one string theorist who has broken the rule with “The Cosmic Landscape” and now “The Black Hole War”.

The Black Hole War is an account of how the puzzle of information loss in black holes was raised by Stephen Hawking and finally resolved by Susskind, ‘t Hooftand other string theorists making crucial use of the Holographic Principle. This principle is a breathtaking idea about the way physics must work which came from work done by ‘t Hooft and Susskind in the mid 1990s. I opened the book with keen interest about how the idea had developed.

‘t Hooft (being a Nobel Laureate) has himself written a popular science book called “In Search of the Ultimate Building Blocks”. There is nothing wrong with the book but I found it disappointing because it only has a few short chapters at the end that get into quantum gravity. The Holographic Principle is not mentioned. It is almost as if ‘t Hooft himself does not recognise just how important his insight turned out to be, perhaps because he does not really like string theory and that is where its impact was felt most.

Susskind certainly does recognise the importance and it is his work that brought it to prominence. However, from this book and the literature it seems to have been ‘t Hooft that first discovered it.

I dont want to spoil the book any more than that, but I will say that if you are interested in how big ideas come about in physics then this is one read you will enjoy.