Tuesday, June 19, 2018

Different phases of growth and change in human organisations

When reflecting on the current state of an organisation (whether a university, a research group, an NGO, a funding agency, a state government department, a business, ...) it is natural to consider two questions.

How did it get to where it is today? In particular, what is the origin of its current positive and negative properties?

What can be done to move it in a positive direction in the future?

Human organisations are complex and diverse, yet their evolution as they grow seem to exhibit certain universal features, that transcend both the purpose and the relative size of the organisation.
There is a classic article, Evolution and Revolution as Organizations, by Larry E. Greiner, originally published by the Harvard Business Review in 1972.

The article is summarised in the figure below.

Greiner was solely concerned with businesses. However, this model has since been applied to other types of organisations.
Aside: His article contains no data or references! Perhaps, his excuse is that he wrote the article in a Swiss ski resort (long before the internet) while recovering from a skiing injury!

I will illustrate the model by considering how it might describe the evolution of a scientific research group. It starts with a young faculty member and ends being part of a large research institute.

Phase 1: Creativity.
A young assistant professor (PI) starts a new research group with start-up funds and two graduate students. They are attracted to work with her because of her passion and the excitement of working on a new technique from the ground up. Lots of different things are tried to get the technique to work. Indeed the original technique does not work but a new one is discovered. Everyone works long hours in the lab. The future is uncertain. She may not get funding or tenure. There is frequent and informal communication within the group. Thus, there is really no need for formal group meetings or policies. After about five years things start to change. Papers are published. Grant applications are successful. More grad students and a postdoc join the group. Tenure is granted. But some frustrations grow as the informality no longer works. The leader spends less time in the lab, travels more, and is less available to students. This leads to the next phase.

Phase 2: Direction.
There is a need for consolidation and organisation. The new technique is now well established. The goal is now to use it as much as possible on a suite of materials. The focus is on fine tuning the technique not on making big new discoveries. Creativity is valued less. There are now weekly group meetings. Each student has a weekly meeting with the PI. Communication becomes more formal and the relationships more distant. The group is now producing a steady stream of papers attracting more grants, and is now joined by undergraduates, visiting faculty, and more grad students and postdocs. There are now formal policies about lab use. People now join the group for different reasons than before. Some are attracted by stability or reputation. Frustrations are present and conflicts associated with competition for resources, whether concerning access to instruments, time with the PI, or author order on papers. The success of the group leads to it attracting more resources. But, this comes with the cost of increased accountability and the associated administrative load. The PI now spends more time communicating with funding agencies, university management, and collaborators, than with people in the group. The PI is rarely seen in the lab, and enjoys her job less.

Phase 3: Delegation.
The PI now delegates supervision of graduate students to postdocs. A technical officer is hired to manage the lab. A group secretary (or PA) takes care of many administrative matters and schedules meetings between group members and the PI. A theory postdoc is hired to do in-house theory. The department hires a new junior faculty member to work in a research area that has some overlap with this well-established group. As the group grows into new areas it becomes divided by research topic or technique. Competition between sub-groups emerge for resources and attention. The PI has lost control over the whole operation and there is a lack of co-ordination between sub-groups.

Phase 4: Co-ordination.
Part of the research group moves into new labs in a new institute building on campus, with a newly hired director. He works with his business manager to impose co-ordination between research groups. The original PI often receives attractive job offers and finally moves to a different university, partly in frustration. The institute director uses this as an opportunity to "reorganise" the different groups in the institute with the goal to make them co-ordinate better about use of instruments, grant applications, and collaborations. He also puts pressure on each group to be self-sustaining financially.
Things have now become quite impersonal and bureaucratic. Some graduate students now join the group because they are impressed by the shiny new building and all the expensive instruments in the lab. But some, older graduate students and postdocs resent the "managers" who they consider have little experience at the "coal face" of research. There is not much innovation or creativity happening. This all leads to the "red-tape" crisis.

Phase 5: Collaboration.
Greiner claims:
The last observable phase emphasizes strong interpersonal collaboration in an attempt to overcome the red-tape crisis. Where Phase 4 was managed through formal systems and procedures, Phase 5 emphasizes spontaneity in management action through teams and the skillful confrontation of interpersonal differences. Social control and self-discipline replace formal control. This transition is especially difficult for the experts who created the coordination systems as well as for the line managers who relied on formal methods for answers.
I remain to be convinced whether this actually ever happens. It is certainly what is desirable, but the obstacles to it happening seem formidable.

Greiner claims that each phase of growth produces problems that lead to a revolution.
But, in each phase of growth the solutions implemented in the previous revolution inevitably produce problems that lead to a new crisis and revolution.
Ironically, for a business professor this determinist perspective (inevitability) is a somewhat Marxist view of history!

A second important claim is that the type of managers or leaders required at the different phases have quite different personalities, strengths, skills, values, and training. Consequently, each revolution is associated with a time of conflict within the organisation.

Why am I interested in all of this? How is it relevant to universities?
There are two ideas that I think are particularly important.

The first idea, is that different phases of growth attract quite different types of people to the organisation. The first phase tends to attract creative people who are driven by passion for thinking, learning, and research. They are independent thinkers who tend to dislike formality and structure.
In contrast, success and growth leads to attracting people who may be more motivated by money, power, or social status. Furthermore, they may be more passionate about organisation, procedures, and structures, than the actual original "core business." In fact, they would be just as happy working in HR, finance, or management in a soft drinks company, a large NGO, as in a university. These differences inevitably lead to conflicts of values. I think this is actually one of the major problems of research universities today. They have become so "successful", large, wealthy, and complex, that they now attract the "wrong" type of people to leadership and management. Passion for transformative education of undergraduates and for creative diligent scholarship is just not present.

The second idea, is the incredible challenge of going from phase 4 to phase 5. In a complex and large organisation how do you create a culture and structures that use the massive resources of the large organisation to actually foster the creativity, entrepreneurship, flexibility, and passion of "grass roots" activities that were present at stage 1, and are essential for the long-term viability and relevance of the organisation.

What do think about Greiner's growth model?
How is it relevant, whether to research groups, departments, or universities?

Friday, June 15, 2018

Quantum spin liquid on the hyper-honeycomb lattice

Two of my UQ colleagues have a nice preprint that brings together many fascinating subjects including strong electron correlations and MOFs. Again it highlights an ongoing theme of this blog, how chemically complex materials can exhibit interesting physics. A great appeal of MOFs is the possibility of using chemical "tuneability" to design materials with specific physical properties.

A theory of the quantum spin liquid in the hyper-honeycomb metal-organic framework [(C2H5)3NH]2Cu2(C2O4)3 from first principles 
A. C. Jacko, B. J. Powell

What is a hyper-honeycomb lattice?
It is a three-dimensional version of the honeycomb lattice.
A simple tight-binding model on the lattice has Dirac cones, just like graphene.

The preprint is a nice example how one can start with a structure that is chemically and structurally complex and then use calculations based on Density Functional Theory (DFT) to derive a "simple" effective Hamiltonian (in this case an antiferrromagnetic Heisenberg model of coupled chains) to describe the low-energy physics of the material.
We construct a tight-binding model of [(C2H5)3NH]2Cu2(C2O4)3 from Wannier orbital overlaps. Including interactions within the Jahn-Teller distorted Cu-centered eg Wannier orbitals leads to an effective Heisenberg model. The hyper-honeycomb lattice contains two symmetry distinct sublattices of Cu atoms arranged in coupled chains. One sublattice is strongly dimerized, the other forms isotropic antiferromagnetic chains. Integrating out the strongest (intradimer) exchange interactions leaves extremely weakly coupled Heisenberg chains, consistent with the observed low temperature physics.
There is some rather subtle physics involved in the superexchange processes that determine the magnitude of the antiferromagnetic interactions J between neighbouring spins. In particular, there are destructive quantum interference effects that reduce one of the J's by an order of magnitude and increases another by an order of magnitude. To illustrate this effect, the authors also evaluate the J's when one flips the sign of some of the matrix elements in the tight-binding model. Similar subtle physics has also been observed in different families of organic charge transfer salts.

As an aside, there is some similarity (albeit many differences) with the basic chemistry of the insulating phase of cuprates: the parent compound involves a lattice of copper ions (d9) where there are three electrons in eg orbitals that are split by a Jahn-Teller distortion. The differences here are first, that the interactions between the frontier orbitals on the Cu sites is not via virtual processes involving oxygen p-orbitals but rather via pi-orbitals on the oxalate bridging orbitals. Second, the lattice of Cu orbitals is not a square but the hyper-honeycomb lattice.

The preprint is motivated by a recent experimental paper in JACS
Quantum Spin Liquid from a Three-Dimensional Copper-Oxalate Framework 
Bin Zhang, Peter J. Baker, Yan Zhang, Dongwei Wang, Zheming Wang, Shaokui Su, Daoben Zhu, and Francis L. Pratt

Thursday, June 7, 2018

Three important questions for talk preparation

I have lots of experience giving talks, on a wide range of topics, and to a diverse range of audiences. Some people say I give nice talks. However, preparing good talks remains a struggle and requires a lot of work, particularly for a new topic and/or a new audience. This week I am give two such talks and have been getting some feedback on drafts. Here are the three questions I have to keep coming back to.

Who is my audience?
What is their background, interests, and prejudices?
The talk MUST be tailored to my actual audience, not a different audience, including the audeince I might wish I had.

What is the context of my talk?
Why was I invited?
Who is speaking before me and after me?
When does my talk occur?
A colleague recently told me to cut a lot of material/information from a draft simply because my talk  will occur on friday before lunch. The audience will be quite tired after five days of intense meetings, discussions, and presentations.
This is quite different to giving the first presentation at a meeting, and which is meant to set the stage, direction, and context for a meeting.

What is the one point I want my audience to take away?
People may not remember or even understand a lot of the detail. What is the single outcome I really want: read my paper, get a job offer, realise theory X is wrong, realise technique Y can help measure Z,  believe A is an exciting new field, give money, stop believing B, be excited about what they are doing, want to collaborate with me on C, generate discussion about D ....?
Focussing on this outcome gives the freedom to cut a lot from the talk and to tailor it to this one single goal rather than a multitude of worthwhile but less important goals.

Not every talk is or should be a TED-style talk but I found very helpful, The Top 5 TED talks about how to give a great TED talk.

Wednesday, May 30, 2018

Broken symmetry, order, and entropy

One of the greatest joys of teaching is having students ask questions that you do not know the answer to. In the last week of the course PHYS2020 Thermodynamics and Condensed Matter Physics for second year undergrads at UQ, I give two lectures about critical points, universality, critical exponents, broken symmetry, order parameters, and Landau theory.

Many students find this quite challenging. However, I think it is important that students be exposed to two of the most important ideas of theoretical physics from the twentieth century: broken symmetry and universality. Furthermore, there is no technical reason why second year undergrads cannot learn this material. Since the text, Thermal Physics by Schroeder, does not cover this material we have finally settled on a chapter from a book by Hoch.

After my last lecture, a student asked an excellent question along the lines of
"Why is it that broken symmetry occurs at lower temperatures?
How is this related to entropy and order?"

This led me to wondering whether there were any rigorous results that answer the question. I could not find anything in a quick search.
Do you know of anything?

I was wondering whether something like the following conjecture was true:
Conjecture. Consider a physically reasonable Hamiltonian H for an infinite system. Suppose H is invariant under some symmetry group G. Let rho(T) be the equilibrium density matrix at temperature T. Then for sufficiently large T, rho(T) is also invariant under G.
Maybe this is equivalent to
Lemma. At sufficiently high temperatures, the von Neumann entropy S (rho) = - Tr( rho ln (rho)) is maximal if rho is invariant under G. 
This looks to me like the kind of thing that people like Elliot Lieb, David Ruelle, Y. Sinai, ... might have tackled at some point.

I welcome ideas and suggestions.

Monday, May 28, 2018

Pushing back against the multi-versity

One of the many concerns I have about universities, particularly in Australia, is the trend to compartmentalisation, factionalisation, fragmentation, obscure over-specialisation, ...
Long ago visions of the UNIversity included unity of knowledge, collegiality, and combining breadth and depth, ...
This trend to the multi-versity manifests itself in diverse ways:
- the lack of appreciation for the value of a liberal arts education
- students who are reluctant to see the relevance of previous subjects and course they have studied to the one they are studying right now, and more broadly the value of other majors (e.g. maths to physics, physics to chemistry, chemistry to biochemistry, history to sociology, philosophy to everything, ....)
- departments that ruthlessly compete with one another for student enrolments
- a ridiculous diversity of undergraduate majors, minors, and degrees
- claims that all points of view are equally valid and should not be critiqued
- a lack of interest in big ideas, big questions, and big issues

In light of this I was fascinated to read about an initiative of the current President of Princeton, Christopher Eisgruber. The Pre-Read has now been running for six years. Before they arrive on campus all Freshman are sent a copy of the same academic book to read and discuss.
In a recent short article, Eisberger discusses the criteria he uses for selecting the book each year.
 The Pre-read’s author speaks to the incoming class at the Freshman Assembly during Orientation week. The book also forms the basis of my Opening Exercises remarks, and I lead Pre-read seminars in the residential colleges during the fall semester.
His two primary goals are to "introduce students to Princeton's vibrant intellectual culture" and "to encourage students to reflect on the values that should guide their Princeton educations and their lives after graduation''.

There are many things I like about the initiative. One is that it helps encourage civil, robust, and intellectually rigorous debate among the students.
Another positive is that the university president himself interacts with the undergrads about the book. This not only has benefits for the students but also for the President himself (and consequently the whole university) because he is exposed first hand to "coal face". I emphasised this point earlier in a post All University Managers should have to teach.
[Aside. I am very happy that the UQ Provost is currently helping teach an undergrad physics class.].

There is many things that Princeton does that other universities cannot do due to lack of resources. However, this is actually an initiative that almost any university could do.

Do you know of other similar initiatives?

Wednesday, May 23, 2018

Metrics and mental health

I never thought I would write a post linking the two issues in the title.

I have been working on my talk on mental health for the School of Maths and Physics colloquium on friday. Here is the current version of my slides. I welcome any comments.

In my preparation I have become aware of a few more resources. A recent issue of Nature includes several articles, including:

An Editorial, What to do to improve postgraduate mental health.
Four researchers write from their own experience, How to handle the dark days of depression
A collection of resources.

On the one hand, it is wonderful that Nature is highlighting the issue. On the other hand, it would be nice if they reflected how Nature Publishing Group might actually be part of the problem, as they mindlessly promote metrics and their journals. It is a case of corporate "well-washing."
The link between metrics and mental health is brought out in a report to the Higher Education Funding Council for England.

The Metric Tide, Report of the Independent Review of the Role of Metrics in Research Assessment and Management, July 2015. The preface states:
Too often, poorly designed evaluation criteria are dominating minds, distorting behaviour and determining careers. At their worst, metrics can contribute to what Rowan Williams, the former Archbishop of Canterbury, calls a “new barbarity” in our universities. 
The tragic case of Stefan Grimm, whose suicide in September 2014 led Imperial College to launch a review of its use of performance metrics, is a jolting reminder that what’s at stake in these debates is more than just the design of effective management systems. 
Metrics hold real power: they are constitutive of values, identities and livelihoods. 

Monday, May 14, 2018

Conducting metallic-organic frameworks

Thanks to the ingenuity of synthetic chemists metallic-organic frameworks (MOFs) represent a fascinating class of materials with many potential technological applications.
Previously, I have posted about spin-crossover, self-diffusion of small hydrocarbons, and the lack of reproducibility of CO2 absorption measurements in these materials.

At the last condensed matter theory group meeting we had an open discussion about this JACS paper.
Metallic Conductivity in a Two-Dimensional Cobalt Dithiolene Metal−Organic Framework 
Andrew J. Clough, Jonathan M. Skelton, Courtney A. Downes, Ashley A. de la Rosa, Joseph W. Yoo, Aron Walsh, Brent C. Melot, and Smaranda C. Marinescu

The basic molecular unit is shown below. These molecules stack on top of one another, producing a layered crystal structure. DFT calculations suggest that the largest molecular overlap (and conductivity) is in the stacking direction.
Within the layers the MOF has the structure of a honeycomb lattice.

The authors measured the resistivity of several different samples as a function of temperature. The results are shown below. The distances correspond to the size of the compressed powder pellets.

Based on the observation that the resistivity is a non-monotonic function of temperature they suggest that as the temperature decreases there is a transition from an insulator to a metal. Since there is no hysteresis they rule out a first-order phase transition, as is observed in vanadium oxide, VO2.
They claim that the material is an insulator about about 150 K, based on fitting the resistivity versus temperature to an activated form, deducing an energy gap of about 100 meV. However, one should note the following.

1. It is very difficult to accurately measure the resistivity of materials, particularly anisotropic ones. Some people spend their whole career focussing on doing this well.

2. Measurements on powder pellets will contain a mixture of the effects of the crystal anisotropy, random grain directions, intergrain conductivity, and contact resistances. This is reflected in how sample dependent the results are above.

3. The measured resistivity is orders of magnitude larger than the Mott-Ioffe-Regel limit. suggesting the samples are very "dirty" or one is not measuring the intrinsic conductivity or this is a very bad metal due to electron correlations.

4. It is debatable whether one can deduce activated behaviour from only an order of magnitude variation in resistance, due to the narrow temperature range considered.

The temperature dependence of the magnetic susceptibility is shown below, and taken from the Supplementary material.

The authors fit this to a sum of several terms, including a constant term and a Curie-Weiss term. The latter gives a magnetic moment associated with S=1/2, as expected for the cobalt ions, and an antiferromagnetic exchange interaction J ~ 100 K. This is what you expect if the system is a Mott insulator or a very bad metal, close to a Mott transition.

Again, there a few questions one should be concerned about.

1. How does this relate to the claim of a metal at low temperatures?

2. The problem of curve fitting. Can one really separate out the different contributions?

3. Are the low moments due to magnetic impurities?

The published DFT-based calculations suggest the material should be a metal because the bands are partially full. Electron correlations could change that. The band structure is quasi-one-dimensional with the most conducting direction perpendicular to the plane of the molecules.

All these questions highlight to me the problem of multi-disciplinary papers. Should you believe physical measurements published by chemists? Should you believe chemical compositions claimed by physicists? Should you believe theoretical calculations performed by experimentalists? We need each other and due diligence, caution, and cross-checking.

Having these discussions in group meetings is important, particularly for students to see they should not automatically believe what they read in "high impact" journals?

An important next step is to come up with a well-justified effective lattice Hamiltonian.