Life transitions

Sometimes I never get around to writing or finishing planned blog posts. Last month something changed, but nothing changed for me. None of this is covid-related.

Three years ago I negotiated with my university a "transition to retirement" contract. These seem to be designed by the accountants to incentivize "highly paid old farts" to retire (regardless of whether they have anything to contribute) and make the university "financially sustainable". I got to go half-time for three years with no teaching and administrative responsibilities.  (BTW. I actually love teaching. I just don't enjoy it or see the point when it becomes bureaucratic and/or students are disengaged.) Pretty strong incentive!

I did this for a multitude of reasons: mental health, other opportunities and priorities, an unwillingness to take on administrative roles that seem to be mostly implementing dubious management decisions, and general concerns about where Australian universities are heading...(money, management, marketing, and metrics)...  Taking long service leave helped clarify things. Since then the wisdom of decision for me personally has only been confirmed, particularly with covid and some family health issues. I could not imagine that I would have coped with having to teach online with two weeks notice. I admire those of you who have done it... And then there are other things in the background such as an opinion piece in The Wall Street Journal  and associated submissions to a recent parliamentary inquiry...

At end of February, the three years came to an end and I officially "retired" and became an Emeritus Professor. My wife says I have not "retired" but just changed to new responsibilities and income streams.  I agree.

I am 60. I consider myself very blessed and privileged that I am able to do this. Not everyone has this freedom. I had about 25 years in Australian universities and most of it was as "research faculty" and I was generously funded and so got to work with many excellent postdocs.

In the short term very little has changed (besides the paychecks). I still have an office, am finishing Condensed Matter Physics: A Very Short Introduction, and collaborating with Ben Powell's group on spin-crossover materials, and trying to write more blog posts. I think some of this work is the nicest I have been involved with. I also work half-time as a consultant for a Christian NGO on a project that combines some of my passions and concerns: science, theology, Jesus, and the Majority World. Again I feel privileged to have that opportunity.

I am hardly "a man of leisure," contrary to what one of my wife's friends said last week.

So what about this blog? I have no immediate plans to change anything. I would like to post more often but always seem too "busy" or spend too much time polishing posts...

Crowdsourcing answers to some science questions

Often when I write a post commenter's suggest some useful references. Answers to any of the following questions would be appreciated. The questions relate to things I am curious about, working on or subjects of possible blog posts.

1. Quasi-particles are a key concept in quantum many-body theory. Is there an analogous concept in classical many-body systems, e.g., dense liquids or plasmas?

2. Is there a simple physical argument, possibly accessible to non-experts, of why decreased dimensionality leads to increased fluctuations?
(An example is the Mermin-Wagner theorem). I understand how to mathematically show that fluctuations increase due to decreased phase space, but I am skeptical that I could make this argument comprehensible to a non-expert?

3. Why does increased CO2 in the atmosphere lead to an increased frequency of extreme weather events (cyclones, droughts, floods, ...)? What is the basic physics involved?
This is the scientific aspect of climate change that I understand the least. It also seems to be the aspect of climate change that could be the worst. I write this in the context of the current bushfires in Australia.

4. Who was the first person to write down the Landau theory for a superfluid transition, suggesting that the order parameter was a complex number?
Was it Ginzburg and Pitaevskii in 1958?

5. Who was the first person to fully appreciate that at a critical point the correlation length of the order parameter diverges and fluctuations in the order parameter become large?
[In 1914 Ornstein and Zernike solved this problem for a liquid-gas transition].

6. Are there philosophical problems or paradoxes associated with the principle of least action in quantum mechanics?
Consider a particle that moves from x at time t to x' at time t'. The path taken is that which is an extrema of the action (time integral of the Lagrangian) along that path relative to others. Superficially, that sounds like the particle ''considers" all the possible paths and then "chooses" the right one. Spooky action at a distance? This makes it sound like to understand classical mechanics you have to consider it as a limit of quantum mechanics and just perhaps embrace the many-worlds interpretation....

Ten years of blogging!

I just realised that last month I had been blogging for ten years.
On the five year anniversary, I reflected on the influence that the blog has had on me.
I don't have much to add to those reflections. The second five years has not been as prolific but has been just as enriching and I am grateful for all the positive feedback and encouragement I have received from readers.

Advice for beginning bloggers

A friend asked me for any advice I have before he launches a blog. What mistakes have I made? How do I manage comments? What is the best platform?

So here are my rough thoughts.

Just do it!

This applies to both starting, persevering, and what you write. Blogging is not for perfectionists and procrastinators. A major strength (and weakness) of the medium is that one can float tentative and controversial ideas and not worry about endless editing and polishing. It can be an incredibly enriching experience, for both yourself and others.

The biggest impact of your blog may be on you not on your audience.

This is really true in my case. Blogging has clarified my thinking on a wide range of issues, from science to politics to religion.

Blogging saves time rather than taking time.

Don't be driven by metrics.
It is easy to keep track of page views and an abundance of other data. It is not clear how accurate or helpful it is. Furthermore, this can easily lead to feelings of insecurity and a temptation to write "click bait". I think the only really meaningful "metrics" are whether a post generates some useful discussion, someone learns something, or even changes their mind.

Go for the long haul.

Many people start blogs but quickly give up because they don't get much feedback. After about four years I was really wondering whether many people were reading this blog or whether it was having much impact. Then on an international trip, I kept meeting people who read it and thanked me for it. This provided motivation to keep going.

Most readers enjoy a diverse range of subjects.
That is the feedback I received from many readers, as I traverse from the technicalities of constructing diabatic states to mental health to teaching philosophy to ranting about metrics .... Obviously, some posts will be of more interest to some readers than to others. Don't worry about it.

Find ways to stimulate discussion in the comments section
This is probably my only regret. I was too slow to ask readers questions, to engage in discussion with commenters and to allow anonymous comments. On the one hand, I have not attracted as many comments as I would like. I am quite "jealous" of some of the discussions that people like Peter Woit, John Quiggin, and Peter Enns [there is an interesting mix of three people!] can generate. On the other hand, I have been blessed by the absence of trolls or the inane comments or abusive debates that seem so common on many blogs, youtube, and newspaper websites. The only comments I have felt the need to delete are spam advertising. But maybe I am not controversial enough to generate heated debate. One thing I do have to discipline myself is to not "name and shame" scientists and administrators that I think are charlatans. There are also certain topics I just avoid because it tragically seems almost impossible to have a civil online discussion and I am too scared of getting "condemned" for life for exploring some nuanced view that is "offensive", whether to people on the left or on the right.

Keep the software and formatting simple
There are endless possibilities for flashy formats. I am sticking with the most basic blogger.com format. There are plenty of popular and valuable blogs (e.g. John Quiggin and Peter Woit) that also use rudimentary formats. I suspect wordpress may be better than blogger.com because it does give more reliable and wider statistics.

Do readers or bloggers have other suggestions for someone about to start out?

Big changes in universities?

I was recently asked to give a talk to an NGO about how universities are changing.
There is no doubt that there are rapid changes, many for the worse, happening. For me the biggest change has been the rising influence of neoliberalism (free market ideology) in the values, goals, and decision making within universities. But that is another story...
In the past few weeks some relevant articles "came across my desk" [through my web browser...].

I would be particularly interested to hear readers comments on the first one.
My wife sent me this New York Times piece to read and I really despaired
The iGen Shift: Colleges Are Changing to Reach the Next Generation 
The newest students are transforming the way schools serve and educate them, including sending presidents and deans to Instagram and Twitter.

Why do I despair?
I believe a university education should largely be about two things. The first goal is explicit and the second is implicit.

The first and primary goal of university education is to help students to learn to think: to think about specific disciplines, and to think about anything. Deep and valuable thinking does not come easily. It takes time, concentration, perseverance, and freedom from distractions. It a student is constantly checking their phone or just skimming the first material that comes up on a Google search or in the Twitter (for twits!) feed for their course, it is highly unlikely they are going to do much deep thinking.

Second, a university education is about helping students "grow up":  to move towards adulthood, to learn to be responsible and independent, to create an identity that is more independent of their parents and their peers, to have a sense of direction and purpose, and a desire to be good citizens.
Unfortunately, too many students think "growing up" means getting really drunk and throwing up...
However, too many of the initiatives described in the article seem to be pandering to students (customers) and "hand holding" them through their university experience. For example, at some point in life students are going to have to learn to seek and find relevant information, regardless of whether it is nicely packaged in some cool app with great graphics and lots of "likes".

Oh, the Humanities! 
New data on college majors confirms an old trend. Technocracy is crushing the life out of humanism.
Ross Douhat (NYT op-ed columnist)

The third article is more controversial and political, and raises questions about whether one purported change is as big or significant as often claimed (particularly in the right-wing press)
The free speech panic: how the right concocted a crisis
Snowflake students have become the target of a new rightwing crusade. But exaggerated claims of censorship reveal a deeper anxiety at the core of modern conservatism.
William Davies (A Long Read in The Guardian)
For balance here is a counter-view that there is a problem
The Problem of Hyper-liberalism
John Gray (Times Literary Supplement)

Comments welcome.

David Pines (1924-2018): quantum-many body theorist

I learnt today that David Pines died last week. He was a pioneer in quantum many-body theory, applying it not just to solid state physics but also to nuclear physics and astrophysics (neutron stars).  Furthermore, he was a great advocate of the importance of emergence in science, writing a classic paper, "The Theory of Everything," together with Bob Laughlin.

David also left a legacy of creative new institutions, being a co-founder of the Sante Fe Institute and the International Institute for Complex Adaptive Matter (I2CAM). Indeed, starting this blog was stimulated by David Pines and I2CAM. In January 2009, I attended the annual meeting of I2CAM in Cambridge and David organised a session on public outreach, including a presentation on blogging.

Piers Coleman, a current co-Director of I2CAM, has written a nice obituary which gives more details about David's contributions, both scientific and institutional.

My ambivalence to anonymous blog comments

Although this blog has a wide readership one thing it struggles with is to attract many comments, and particularly much back and forth discussion. Sometimes people tell me that this is just because it is not provocative or controversial enough.

A while ago I changed the settings to allow anonymous comments and this has led to an increase in comments which is encouraging. However, I do have some ambivalence about this. 

Ideally, any comment and opinion should be judged on the merits of its content not based on who is giving it. We should beware of arguments from authority. On the other hand, that is not the way most of us think and act. We do give some weight to the author. For example, an anonymous commenter says "I am a physicist and I am a climate change skeptic" it does not have the same weight as the opinion of a respected physicist who has relevant expertise.

I am also concerned that people are not willing to take the risk of being publically identified with their views. This does not just reflect on the commenter but also reflects poorly on the scientific and academic community. Why are people so hesitant? Is the community so intolerant of controversial views? 

Here I should say I am very sympathetic to some peoples nervousness. At least twice, I suggested to younger colleagues who did not have permanent jobs that they delete specific comments they made on the blog that were critical of the "establishment".

I welcome discussion.

Nevertheless, please don't let my ambivalence stop you making comments.

Are theoretical physics and chemistry amenable to online collaboration?

Last week at UQ we had a very nice mathematics colloquium, "Crowdsourcing mathematics problems" by Timothy Gowers.
He first talked about the Polymath project, including its successes and marginal contributions.
He then talked about a specific example of a project currently underway on his own blog, concerning transitive dice. This was pretty accessible to the general audience.

This is where a well defined important problem is defined on a blog and then anyone is free to contribute to the discussion and solution. A strength of this approach is that it makes use of the complementary strengths, experience, and expertise of the participants. Specifically, solving problems includes:

• selecting a problem that is important, interesting, and potentially ripe for solution
• defining the problem clearly
• breaking the problem down into smaller parts including conjectures
• sketching a possible heuristic argument for the truth of the conjecture
• giving a rigorous proof of the conjecture
• finding possible counter-examples to the conjecture
• connecting the problem to other areas of mathematics

This can be efficient because dead ends and mistakes are found quicker than someone working in isolation. 

People are more motivated and engaged because they are excited to be working on something bigger than themselves and what they might normally tackle. And they enjoy the community.

What about assigning credit in such group work? There is a clear public record of who has contributed what. Obviously, this does not work for bean counters looking at traditional metrics.

This approach mostly attracts senior people who are secure in themselves and their career stage and more interested in solving problems than getting individual credit.

The cultural differences of pure mathematics and physics was striking. The talk was given on whiteboards and blackboards without notes. No powerpoint! The choice of research problems was purely based on curiousity, not any potential practical value or the latest fashion. It is fascinating and encouraging that the pure mathematics community is still "old school" with the focus on quality not quantity.

Aside: Gowers is also well known for initiating a boycott of Elsevier journals.

Now, my question. 

What is stopping theoretical chemistry and physics from such a "crowd sourcing" approach? 

Is it that the problems are not amenable? 

Or is it largely that we are too driven by a system that is fixated on individual credit?

My post on why I don't worry about getting scooped may be relevant.

Should you quit social media?

The New York Times has an interesting Op-ed. piece Quit Social Media. Your Career May Depend on It, by Cal Newport, a faculty member in computer science at Georgetown University.

When I saw the headline I thought the point was going to be an important one that has been made many times before; people sometimes post stupid stuff on social media and get fired as a result. Don't do it!
However, that is not his point.
Rather, he says social media is bad for two reasons:

1. It is a distraction that prevents deep thinking and sustained  "deep" work. Because you are constantly looking at your phone, tablet, or laptop or posting on it, you don't have the long periods of "quiet" time that are needed for substantial achievement.

2. Real substantial contributions will get noticed and recognised without you constantly "tweeting" or posting about what you are doing or have done. Cut back on the self-promotion.

Overall, I agree.

When I discussed this and my post about 13 hour days with two young scientists at an elite institution they said: "you really have no idea how much time some people are wasting on social media while in the lab." Ph.D students and postdocs may be physically present but not necessarily mentally or meaningfully engaged.

A similar argument for restraint, but with different motivations, is being advocated by Sherry Turkle, a psychologist at MIT. Here is a recent interview.

I welcome discussion.

Weird spikes in blog traffic

The plot shows the number of page views on this blog during the last week, according to blogspot.com. During one hour there was several thousand hits! 20-50 per hour is more normal.
A similar thing happened a year ago.

My fantasy would be that some celebrity tweeted me. Perhaps they liked my post about Drumpf university? However, that is highly unlikely. The spike does not show up in Google analytics (which by the way always shows consistently lower traffic). Furthermore, a breakdown in terms of individual posts or sources or referrals or geography, shows nothing unusual. I suspect the spike is due to some kind of bot. Any ideas?

Blog highlights from 2015

Best wishes for the New Year!

Here is a selection of posts from last year I thought were the best and/or the most satisfying to write.

Are American universities Crystal Cathedrals?

Is DMFT the "only game in town"?

Battling High Impact Factor Syndrome. II

What the ten key concepts in quantum many-body physics?

The two biggest obstacles to science Ph.Ds getting a job in industry

A nice write up in Physics World

Common challenges with constructing diabatic states and Wannier orbitals

Conical intersections vs. Dirac cones. Chemistry vs. Physics.

Emergence and singular asymptotic expansions. II

Engaging Indian school students in real science experiments

There is no metal-insulator transition in extremely large magnetoresistance materials. 2.

Thanks again to all the readers who provided positive feedback last year, and particular thanks to those who wrote comments on the blog. Hope to see more in 2016!

I welcome suggestions on possible topics for future posts.

A nice write up in Physics World

Physics World [Magazine for the Institute of Physics (UK) = British equivalent of Physics Today] has a feature Web life that covers different web sites.

The June 2015 issue features this blog!
Besides the publicity, I was really happy because I felt the article nicely captured what I am on about. I was not interviewed and only heard about it from a Commenter, Peter Morgan.

One mild amusement was that I was classified as "a chemical physicist". I would certainly classify myself as a "condensed matter physicist" who sometimes tries to do chemical physics. So I took this as a compliment!

Superfluid helium on prime time TV

Unfortunately, The Big Bang Theory TV show features little physics these days. It is often just like "Friends" except some of the characters happen to work at Caltech. However, a recent episode, "The Troll Manisfestation" centred on superfluid helium and also mentions co-authorship, the arXiv, and physics blogs. There is some commentary on the physics in the episode by string theorist, Lubos Motl.

Is DMFT "the only game in town"?

Last week Peter Woit kindly recommended my blog to his readers. This immediately doubled the number of daily page views for several days thereafter!

Peter also drew attention to my recent paper with Nandan Pakhira that shows that the charge diffusion constant in a bad metal violates a conjectured lower bound. This bound was conjectured, partly on the basis of arguments from string theory techniques [holographic duality, AdS-CFT]. Our calculations were all based on a Dynamical Mean-Field Theory (DMFT) treatment of the Hubbard model.

One commenter "Bernd" wrote

The violation of the holographic duality bound is based on DMFT calculations, which is a bit like string theory for strongly correlated fermions in the sense that it is somtimes sold as “the only game in town”. Nobody knows how accurate these methods really are.

For background, "the only game in town" refers to a common argument of string theorists that string theory must be correct because there are no others options for a mathematically self-consistent theory of quantum gravity. Woit's blog and book has many counter arguments to this point of view, as for example here. Ironically, a  commenter Carl points out

The quote “the only game in town” is exceptionally apt. It’s most associated with con man “Canada Bill” Jones, master of the Three Card Monte, who ironically was himself addicted to gambling and lost his money to better professionals as fast as he took from marks. Supposedly, on being advised by a friend that the Faro game he was losing money at was rigged, he replied “I know, but it’s the only game in town!”.

I wish to make two points in response to "Bernd".
First, I think we have a pretty good idea of how accurate DMFT is.
Second, I think any analogy between DMFT and string theory is very weak.

We know that DMFT is exact in infinite dimensions. It is an approximation in lower dimensions, that can be compared to the results of other methods. Cluster versions of DMFT give a systematic way to look at how the neglect of spatial correlations in single site DMFT matter. It has also been benchmarked against a range of other numerical methods.

The "sociological" comparison between string theory and DMFT is debatable.
I have never heard anyone claim it is "the only game in town".  On the other hand, there are probably hundreds of talks that I have never gone to where someone might have been said this.
I am a big fan of DMFT. For example, I think combining DMFT and DFT is one of the most significant achievements of solid state theory from the past 20 years. Yet, this is a long way from claiming it is the "only game in town".

It is worth comparing the publication lists of string theorists and DMFT proponents.
String theorists virtually only publish string theory papers reflecting their belief that it is the "only game in town". However, if you look at the publication lists of DMFT originators and proponents, such as Georges, Kotliar, Vollhardt, Metzner, Jarrell, Millis, ... you will see that they also publish papers using techniques besides DMFT. They know its limitations.

If you look at the research profiles of physics departments the analogy also breaks down. Virtually only string theorists get hired to work on "beyond the Standard Model". In contrast, when it comes to correlated fermions, DMFT is a minority, and not even represented in many departments.

Most importantly, there are no known comparisons between experimental data and string theory. DMFT is completely different. For just one example, I show the figure below, taken from this paper, that compares DMFT calculations (left)  to  experiments (right) on a specific organic metal close to the Mott insulator transition.

This organic material is essentially two-dimensional, a long way from infinite dimensions!
Furthermore, the parameter regime considered here corresponds to the same parameter regime [bad metal] that DMFT gives violations of the conjectured bound in the diffusion constant.

DMFT is not "the only game in town". We have a pretty good idea of how and when it is reliable.

Where is all this blog traffic coming from?

Normally this blog attracts about 700 page views per day, according to blogspot. However, yesterday it got 5000! I have no idea why. Presumably someone with a significant following Tweeted it.

If you know the answer, please let me know, even if you are a robot!

I have not seen a traffic increase like that this since I pointed out that Greg Scholes' "quantum biology" paper in Nature involved fitting 20 data points to a curve with 17 parameters.

Significant blog posts from 2014

Best Wishes for the New Year!

In the past, at the end of each year I have listed my most popular [i.e. most viewed] posts of the year. Unfortunately, on blogspot it is now difficult to figure that out. So, here I list ten of the more popular posts I thought were significant/satisfying.

Is the mobility of protons in water high?

Are there quantum limits to transport coefficients?

Slow spin dynamics in the bad Hund's metal

Seeking definitive signatures of quantum criticality

How 5 years of blogging has changed me

My paper submission strategy

A survival and sanity guide for new faculty

Latest talk on mental health for scientists

Is publishing debatable conclusions now encouraged?

An empirical potential to benchmark computational chemistry for hydrogen bonding?

It is particularly satisfying to me that half of these posts are about deep scientific issues, not just my rants about luxury journals, metrics, neoliberalism, quantum biology, ....

Thanks again to my readers. I really appreciate all the positive feedback and encouragement I receive. But, I still dream of more comments and discussion.

How 5 years of blogging has changed me

Last month marked the 5 year anniversary of this blog. My first post was a tribute to Walter Kauzmann. In hindsight, after almost 1500 posts, I think that was a fitting beginning. Kauzmann represented many of the themes of the blog: careful and thorough scholarship, theory closely connected to experiment, simple understanding before computation, hydrogen bonding, fruitful interaction between chemistry and physics, ….

Reflecting on this anniversary I realised that writing the blog has had a significant influence on me. Writing posts forces one to be more reflective. I think I have a greater appreciation of

• good science: solid and reproducible, influential, ...
• how important it is to good science, rather than just publishing papers
• how hard it is to do good science
• today, the practise of science is increasingly broken
• the bleak long-term job prospects on most young people in science
• the danger and limitations of metrics for measuring research productivity and impact
• the importance of simple models and physical pictures
• diabatic states as a powerful conceptual, model building, and computational tool in chemistry
• the importance of Dynamical Mean-Field Theory (DMFT)
• bad metals as a unifying concept for strongly correlated metals

I thank all my readers, and particularly those who write comments.
I greatly value the feedback.
I do want to see more comments and discussion!

My most popular blogposts for 2013

According to blogspot here are the six most popular posts from this blog over the past year

Effective "Hamiltonians" for the stock market

Thirty years ago in Princeton

Relating non-Fermi liquid transport properties to thermodynamics 

Mental health talk in Canberra

What simple plotting software would you recommend?

A political metaphor for the correlated electron community

Thanks to my readers, particularly to those who write comments.

Best wishes for the New Year!

Chemical bonding, blogs, and basic questions

Roald Hoffmann and Sason Shaik are two of my favourite theoretical chemists. They have featured in a number of my blog posts. I particularly appreciate their concern with using computations to elucidate chemical concepts.

In Angewandte Chemie there is a fascinating article, One Molecule, Two Atoms, Three Views, Four Bonds that is written as a three-way dialogue including Henry Rzepa.
The simple (but profound) scientific question they address concerns how to describe the chemical bonding in the molecule C2 [i.e. a diatomic molecule of carbon]. In particular, does it involve a quadruple bond?

The answer seems to be yes, based on a full CI [configuration interaction] calculation that is then projected down to a Valence Bond wave function.

The dialogue is very engaging and the banter back and forth includes interesting digressions such the role of Rzepa's chemistry blog, learning from undergraduates, the relative merits of molecular orbital theory and valence bond theory, the role of high level quantum chemical calculations, and why Hoffmann is not impressed by the Quantum Theory of Atoms in Molecules.

I don't want this blog to become too popular!

This past year I have been surprised and encouraged that this blog has a wide readership. However, I have also learnt that I don't want it to become too popular.

A few months ago, when I was visiting Columbia University I met with Peter Woit. He writes a very popular blog, Not Even Wrong, that has become well known, partly because of his strong criticism of string theory. It is a really nice scientific blog, mostly focusing on elementary particle physics and mathematics. The comments generate some substantial scientific discussion. However, it turns out that the popularity is a real curse.  A crowd will attract a bigger crowd. The comments sections attracts two undesirable audiences. The first are non-scientists who have their own "theory of everything" that they wish to promote. The second "audience" are robots that leave "comments" containing links to dubious commercial websites. Peter has to spend a substantial amount of time each day monitoring these comments, deleting them, and finding automated ways to block them. I am very thankful I don't have these problems. Occasionally, I get random comments with commercial links. I delete them manually. I did not realise that they may be generated by robots.

Due to the robot problem, Peter said he thought the pageview statistics provided by blog hosts [e.g. blogspot or wordpress] were a gross over-estimate. I could see that this would be the case for his blog. However, I suspect this is not the case for mine. Blogspot claims a typical post of mine gets 50-200 page views.  This seems reasonable to me. Furthermore, the numbers for individual posts tend to scale with the number of comments and the anticipated breadth of the audience [e.g. journal policies and mental health attract more interest than hydrogen bonding!] Hence, I will still take the stats as a somewhat reliable guide as to interest and influence.