The relevance of Labor Day to physicists and philosophers

This past Monday, May 8, was a public holiday in Queensland, marking Labor Day. I don't know why we don't celebrate it on May 1, but that does not matter.

In honour of the event, I post two relevant resources. The first resource is a moving video by Sabine Hossenfelder, who has carved out a post-academic income as a populariser of physics. The video is funny and sad, describing her own experience in academia leading to "Death of a Dream".

Sabine has many poignant observations about the dysfunctionalities of physics in academia, from the personal to the intellectual.

I find it sad that people who leave academia because they could not find a permanent job see themselves as a "failure." First,  most of the select few who get permanent jobs do so because they are at the right place at the right time, not because they are so much more brilliant and productive than others. Second, there is so much more to life than professional success. Finally, Sabine has been an incredible success. She has been able to popularise physics far beyond what has been achieved by others with big names and lots of resources. Furthermore, Sabine has made a significant contribution to the physics community by calling out hype and BS.

The second resource to mark Labor Day is an article, 

In Australian Universities, There Is No Such Thing as a Secure Job, by Danny Wardle. 

It puts a specific (alarming) incident in the broader context of the history of how and why the governance and management of Australian universities have been captured by the ideology of neoliberalism. This has been facilitated by the opportunism and vanity of mediocre academics who become "managers" with million-dollar salaries.

Opening the door for women in science

 I really liked reading Transcendent Kingdom by Yaa Gyasi. She is an amazing writer. I recently reread some of it for an extended family book club. Just check out some of these quotes. 

A colleague suggested I might like Lessons in Chemistry, a novel by Bonnie Garmus. I have not read the book yet, but I have watched the first two episodes of the TV version on AppleTV. I watched the first episode for free.

The show contains a good mix of humour, love of science, and feminism. The chemistry dialogue seems to be correct. The show chronicles just how in the 1950s how awful life was for a young woman who aspired to be a scientist. Things have improved. But there is still a long way to go... 

A light slow start to the year

Best wishes for the New Year!

Over the holidays my son introduced me to the humorous wonders of Philomena Cunk. Here is a short sample.

The Story of Science is a nice video series

 I am on the lookout for good video resources about science that I can recommend to others, particularly non-scientists. By chance, I recently came across the BBC production, The Story of Science: Power, Proof, and Passion, hosted by Michael Mosley.

There is also a beautiful book that goes with the series, containing more detail, including colour illustrations. I was able to get the DVDs and the book from my local public library.

I particularly appreciate that science is presented as a human endeavour and progress is influenced by local contexts (economic, political, religious, ...). That can be acknowledged and enjoyed without descending into a social constructivist view of scientific knowledge. In a similar vein, the series does not have an ideological edge, or embrace some common tropes that too often popular video treatments may promote such as science the saviour, science the moneymaker, science the spoiler, science the monster-maker, ... or that science is uncontrollable, is inscrutable, or is the domain of evil/eccentric geniuses,....

The series introduced me to several colourful characters who played key roles in the history of science, including Hennig Brand, Hans Sloan, Georges Cuvier, Horace-Benedict de Saussure, Simon Sevin, Richard Trevithick, ...

Why are superfluids creepy?

 A signature effect associated with superfluidity in liquid helium is that it can climb up the walls of a container and empty the container. This is seen in the video below (beginning at 1:10).

But what is the physics behind this? 

Why is this a signature of superfluidity?

The schematic below is helpful. [It is figure 1.8 in Superfluidity and Superconductivity by Tilley and Tilley.]

We need to distinguish between which parts of the underlying physics occur for all fluids and which only occur for a superfluid.

1. For any liquid in thermodynamic equilibrium inside a container there is some vapour present. Some of this vapour condenses onto the surface of the container, forming a thin film of liquid on the surface. The surface of the liquid is actually not completely flat but curves upwards at the edge of the container surface. An example of this is a concave meniscus that one sees inside a small tube.

2. For a normal fluid the surface film is relatively thin and is pinned to the container surface by the viscosity of the fluid.

3. In superfluid helium the film is thick enough that the superfluid component of the fluid can flow freely. The film also extends to the top of the container walls.

Thus, the superfluid forms a continuous film that extends up and over the container walls. 

4. Superfluid in the film can flow freely if there is a driving force. The difference in gravitational potential energy between the surfaces of the liquid inside and outside the container provides such a driving force. The physics of this is identical to that of a regular siphon. It is just that in the case of superfluid helium the "tube" is the surface film and that due to superfluidity this film can flow.

And so, that is why superfluids are creepy.

Biology in a nutshell: emergence at many levels

 One of the many great things about The Economist magazine is that they run "Briefing" articles that give brief readable introductions and analyses to important topics, ranging from racism to taxation to climate change. Last year they ran a series about new ideas in economics.

They are currently running a series, Biology Briefs. Each week, for six weeks, there is a two-page article on one key topic in modern biology. They are naturally divided by different scales: molecules, cells, organs, individual lives, species, and living planets. 

The most important idea in molecular biology: DNA encodes information that is used to make specific proteins.

Replication: the protein DNA polymerase makes new DNA molecules with the same sequence of base pairs

Transcription: the protein RNA polymerase makes single strands of RNA that have the same genetic information.

Translation: the protein ribosome reads the information in the mRNA and uses it to make chains of amino acids (with specific sequences determined by the RNA sequence). These polymers then fold spontaneously into proteins with specific functions.

There is much that is amazing and awesome about this, including that people have been able to figure all this out. What I find most amazing/miraculous/awesome/cool is not the software but rather the hardware, i.e. the proteins that act as nanoscale biochemical factories, particularly the ribosome.

Springy stringy molecular crystals

Perfect crystals are elastic. When a stress is applied and then removed the crystal will bounce back to its original shape. However, in reality no crystal is perfect. If the applied stress is too large the crystal will fracture. Understanding fracture is a big deal in materials science and involves some fascinating physics, including the role of topological defects. 

There are two distinct properties: elasticity and plasticity. They are associated with temporary and permanent changes in shape in response to an applied stress.

They are quantified by the elastic stiffness and the tensile strength, respectively. They reflect material properties at quite different length scales. 

A beautiful and accessible short introduction is 

Stressed out crystals

Bart Kahr & Michael D. Ward 

This is a commentary of some work by a few of my UQ chemistry colleagues, who have made and studied a molecular crystal that is incredibly flexible, as seen in this movie.

Atomic resolution of structural changes in elastic crystals of copper(II) acetylacetonate

Anna Worthy, Arnaud Grosjean, Michael C. Pfrunder, Yanan Xu, Cheng Yan, Grant Edwards, Jack K. Clegg & John C. McMurtrie 

A particular advance is that they use a synchrotron to perform spatially resolved X-ray crystallography to determine how the crystal structure varies spatially within a bent crystal. 

The material of interest has quasi-one-dimensional antiferromagnetic interactions and has been studied theoretically by my condensed matter theory colleagues.

Mechanomagnetics in Elastic Crystals: Insights from [Cu(acac)2]

Elise P. Kenny, Anthony C. Jacko, Ben J. Powell

But there is more...

A recent Science paper describes ice fibers that were particularly flexible.

Elastic ice microfibers

Peizhen Xu, Bowen Cui, Yeqiang Bu, Hongtao Wang, Xin Guo, Pan Wang, Y. Ron Shen, Limin Tong

The intellectual legacy of Phil Anderson

I am looking forward to reading Andrew Zangwill's book, A Mind Over Matter: Philip Anderson and the Physics of the Very Many, that should be available in January 2021.

Andy recently gave a beautiful talk at an ICAM meeting on the life and science of Phil Anderson. I highly recommend it. Yesterday, at the UQ condensed matter theory group meeting we watched it and discussed it.

A few things that stood out to me, partly because some were new to me.

``PWA was a brilliant intuitionist who did more than any other person to transform the patchwork of ideas and techniques of what was formerly called solid state physics into the deep, subtle, and intellectually coherent discipline know as condensed matter physics.''

Phil's wife, Joyce, had an MA in English literature and edited all his prose pieces. This may explain how well written his writing for general audiences, such as Physics Today columns and book reviews in The Times Higher Education Supplement were so well written. In contrast, Phils talks and some papers were rather obscure.

PWA was a contrarian. He did not follow the pack. This is embodied in the fact that he chose to work on his PhD at Harvard with van Vleck, rather than Schwinger, who was chosen by eleven of his peers! van Vleck said "follow the data". During this time he was a friend of Tom Lehrer, a mathematics graduate student who became famous for writing and performing satirical songs with a strong social justice theme.

Phil did a BS in Electronic Physics (essentially Radio Engineering) and did not learn any modern physics. He did a PhD in chemical physics. It was only at Bell Labs that he started working on condensed matter problems. There he had three significant mentors: Conyers Herring, Gregory Wannier, and Charles Kittel.

Phil's 1952 paper on antiferromagnetism contained the idea of spontaneous symmetry breaking. But, this was not appreciated for a decade.

Phil's 1957 localisation paper and his 1961 magnetic impurities paper [the two works cited for his Nobel Prize] were both stimulated by talking to experimentalists at Bell Labs [George Feher and Berndt Matthias, respectively].

Concepts in Solids, based on his graduate lectures at Cambridge in 1961-2, was revolutionary for the time because the focus was on the properties of model Hamiltonians, rather than detailed phenomenology.

Phil's criticisms of high energy physics, its reductionism and drawing resources away from "tabletop" science, began as early as 1971, when he wrote a New Scientist article on the subject. 

But there is a lot more. Watch the video!

Common examples of symmetry breaking

In his beautiful book, Lucifer's Legacy: The Meaning of Asymmetry, Frank Close gives several nice examples of symmetry breaking that make the concept more accessible to a popular audience.

One is shown in the video below. Consider a spherical drop of liquid that hits the flat surface of a liquid. Prior to impact, the system has continuous rotational symmetry about an axis normal to the plane of the liquid and through the centre of the drop. However, after impact, a structure emerges which does not have this continuous rotational symmetry, but rather a discrete rotational symmetry.



Another example that Close gives is illustrated below. Which napkin should a diner take? One on their left or right? Before anyone makes a choice there is no chirality in the system. However, if one diner chooses left others will follow, symmetry is broken and a spontaneous order emerges.

Debating emergence and reductionism

As part of a TV documentary, Why are we here? produced by Ard Louis and David Malone there is a nice series of interviews where emergence is discussed by George Ellis, Peter Atkins, and Denis Noble.
I can't seem to embed the interviews here and so have put in links to short clips.

George Ellis discusses the difference between weak and strong emergence and his attitude to each.

In separate clips, Denis Noble discusses emergence  and reductionism in biology.

Peter Atkins, a hardcore reductionist, IMHO does not seem to seriously engage with the issue.

Who was the greatest theoretical chemist of the 19th century?

Dimitri Mendeleev, who proposed the periodic table of the elements, purely from phenomenology and without quantum mechanics!
He even successfully predicted the existence of new elements and their properties.

A friend who is a high school teacher [but not a scientist] asked me about how he should teach the periodic table to chemistry students. It is something that students often memorise, especially in rote-learning cultures, but have little idea about what it means and represents. It makes logical sense, even without quantum mechanics. This video nicely captures both how brilliant Mendeleev was and the logic behind the table.



A key idea is how each column contains elements with similar chemical and physical properties and that as one goes down the column there are systematic trends.
It is good for students to see this with their own eyes.
This video from the Royal Society of Chemistry shows in spectacular fashion how the alkali metals are all highly reactive and that as one goes down the column the reactivity increases.



The next amazing part of the story is how once quantum theory came along it all started to make sense!

A lucid lecture on the last 50 years of superconductivity

At the weekly condensed matter theory cake meeting today we watched a video of a KITP blackboard talk given by Piers Coleman in 2015.
Superconducting Surprises: five decades of discovery, in both temperature and time!

It is a very nice exposition of the history and some of the key physics.

A couple of minor comments.

Organic superconductors were discovered in 1980 not 1973.

Piers claims that the difference between the thermodynamic entropy of the superconducting and metallic states (determined from integrating the temperature dependent specific heat) is related to the quantum entanglement entropy of the superconducting ground state.
The relationship between entanglement entropy (defined on a pure quantum state (at zero temperature) which is divided in two) and thermal entropies (defined for a bulk system in a mixed state at finite temperature) is an incredibly subtle and complex issue that I don't think is resolved. See for example the discussion in this paper.

A good video on the discovery of the transistor

I am on the lookout for good videos that meet roughly the following criteria:
-available free online
-on condensed matter or chemistry
-accessible and interesting to a popular audience
-represent the science in a reasonable and helpful way
-lack hype

This is motivated by the following experience. I knew that there were people (mostly young) who will spend endless hours watching trashy videos (whether B-grade movies or silly antics) on Youtube. However, I only recently learned that there are also people who will spend hours watching videos on serious subjects (science, politics, history, religion, ...)

I am keen to find such material so I can recommend it as alternatives to the kind of thing featuring Michio Kaku or string theory propaganda from Brian Greene.

This is why I recently watched Forces of Nature with Brian Cox. Unfortunately, I think only the first episode is available for free.

In my search, I came across this nice history of the discovery of the transistor narrated by Ira Flatow and produced by PBS.

It nicely brings out the healthy interaction between Bardeen's theoretical work and Brattain's experimental work, even when one or both did not work out. They were a great stimulus to one another.

It also discusses the mixed legacy of Shockley, the Broken Genius.




What videos can you recommend that meet the criteria above?

The shape of nature

I watched the first episode of The Forces of Nature narrated by Brian Cox, The Universe in a Snowflake.
[Unfortunately, I don't think the whole episode is free online. It should be! I watched it streamed through my university library website].

The imagery and creativity are stunning.
The episode focuses on shapes that occur in nature: spherical planets, human towers in Spain, hexagonal snowflakes, honeycomb beeswax, and "spherical" manatees, animals with bilateral symmetry,  ...
Cox nicely discusses some of the underlying principles, including how complexity emerges from simple underlying laws.

How do bees "know" that a honeycomb structure is optimal? This relates to a simple example of symmetry breaking and the much more difficult honeycomb conjecture that was only solved in 1999.

A video illustrating the length scales of the universe

Sometimes when I speak about science to church groups I show the old (1977) video Powers of Ten which nicely illustrates the immense scale of the universe and orders of magnitude.
I often wished there was a more polished modern version.
Yesterday it was pointed out to me there is, Cosmic Eye.



The phone app can be purchased here for $1.

How to give a bad science talk

Amongst his one page guides John Wilkins [my postdoc supervisor] has
Guidelines for giving a truly terrible talk

"Strict adherence to the following time-􏰀tested guidelines will ensure that both you and your work remain obscure and will guarantee an audience of minimum size at your next talk􏰁."

Independently, David Sholl has illustrated the problems in concrete ways with an actual talk "The Secrets of Memorably Bad Presentations"

 

I am not sure if it is funny or just plain painful. But it does drive home the points.
All students (and some faculty) should be forced to watch it in full.

John Oliver on science and hype

John Oliver has an impressive ability to combine humour with cutting political and social commentary, and thorough and substantial background research, in a very engaging manner that is accessible to a broad audience.

Recently he tackled the important issue of how the media poorly engages with recent scientific research; but the problem is not just the media but university press offices, some journals, and scientists themselves.



If you cannot view the link above (e.g. because you are in Australia) try to watch it here.

KITP seminars online

A wonderful thing about the web is that now there is so much material online. A pioneer in putting all their seminars and colloquia online is the KITP at Santa Barbara. I know some people who regularly watch seminars (both old and recent). Others do not know it exist. This is a particularly valuable resource for students and those of us in distant countries.

I have to confess that until yesterday I have never actually watched a talk; just occasionally skimmed some slides. Generally I find I don't have the patience to watch talks online. I just seem to prefer to look at papers. However, yesterday I was forced to do this because at the weekly UQ condensed matter theory group meeting we watched a nice talk by Antoine Georges on Hund's metals. Although, I have read and blogged about some of the relevant papers, I really found it helpful seeing what was highlighted and going through the material at a "slow pace". Hopefully, I will do this more often.

What do you think about online talks or lectures? How often do you watch them? Are there any that you would particularly recommend?

Is this the ultimate compliment for your paper?

For someone to put the main points to a popular song!

Yesterday I heard an interesting talk "Truths we must tell ourselves if we are to manage climate change" at UQ by Robert Socolow [aged 80!].

He is well known for a paper, Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies

The paper considers Seven ways to reduce carbon emissions. Glenn Wolkenfeld has written corresponding lyrics to the tune of the classic Paul Simon song, 50 ways to leave your lover!



Socolow has an interesting career history, having started out in theoretical physics, working on elementary particles. I will write more about that career transition later.

Preserving my mental health

In Australia this week is Mental Health Week. 10 October is World Mental Health day.
I have been told that some of my posts and talks about  mental health issues have been helpful and so here are a few random observations.

These are just some things that I have recently noticed and are helpful for myself. They are personal and so may not be helpful  for others. But, hopefully they may stimulate you to think about your own situation.

Overstimulation.
This is one reason to turn off email occasionally.
Do you really need email on your phone?
It is one of the reasons I don’t even have dumb phone!
I am currently in India and something I like about one of the places we regularly stay is there is no internet in our room. You have to walk outside 100 metres to a different building to access it.

Short breaks.
Several times a day I take a brief walk on campus to clear my head.
UQ has quite a nice campus and so this helps.

Exercise.
The more that it is integrated into your weekly/daily routine the better. I am fortunate that my home is 25 minutes walk from my office. A few years ago I started walking home several times a week.
Now I actually walk both to and from work on most days.

Take a Mental health day.
Minimise particularly stressful situations.
I have slowly learnt that there are certain individuals, activities, and organisations [whether social or professional] that take me a while to recover from. It is not possible to avoid all of them! On the one hand, I don't encourage people to run away from problems and difficult situations. On the other hand, you don't have to be a masochist. Sometimes it is best to opt out.

Sleep.
Get enough.
One or two nights with little sleep, either due to stress or travel, gives me a very bleak view of the world.

Daily victories and small satisfactions.
My view of life is much more positive is on each day I can achieve at least one small thing I think is of value or enjoyable. This is where this blog helps. Writing a post gives a concrete and tangible achievement for the day. I struggle to get such satisfaction from administrative responsibilities or research dead ends!

Physical illness may reflect stress and poor mental health.
I got a cold/flu a few months ago. I realised that I had not been sick for a year and that the last few years I rarely get sick. In contrast, in times when I have had a lot of stress I often got sick and sometimes it took me more than a week to shake off a cold/flu. There is a general folklore that stress increases the susceptibility of individuals to colds, flu, and infections. I did a quick search of the medical literature to see if this is really firmly established but could not find anything particularly convincing. Does anyone know of a relevant study?

Nature and humour.
These are two of the best drugs! The video below combines both!