Fighting on

February 24, 2017


Just finished watching Avengers: Age of Ultron (again). Caring for my sick daughter does have its compensations (though I shudder at the backlog piling up at work!) 

The powerful image in the end credits, of the main characters portrayed as classical heroes, in marble, made me reflect on Joss Whedon’s take on heroism. I think it is best captured in the closing words of Angel – with which the 12 seasons of the Buffy/Angel television saga came to an end:

SPIKE: In terms of a plan?

ANGEL: We fight.

SPIKE: Bit more specific.

ANGEL:

(steps forward)

Well, personally, I kind of want to slay the dragon. 

(the demon horde attacks)

Let’s go to work.

(swings his sword)

(Fade to black.)

Or beloved heroes do not die on screen, but we are left in doubt as to what will happen next. 

In the Whedon universe, heroes are not the guys who always win, but the ones who are always ready to put up a fight. This idea is not a Whedon invention, of course, but Whedon does come up with powerful ways to put it forward in the realm of pop culture.

As our world is increasingly crunched between the souless wills of haters and philistines it is good to remind ourselves that heroism is about fighting on, even when it feels like we’ll be crushed. 

Ultimately, heroism (or whatever lesser version of it we, mere mortals, may manage to muster) is not about winning, but just a better way of life. As in the opening lines of that other great piece of pop culture, the feature film Lorenzo’s Oil:

“Life has meaning only in the struggle. Triumph or defeat is in the hands of the Gods. So let us celebrate the struggle.” 

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The naturalness of altruism

September 19, 2016

screenshot-from-2016-09-19-110456

Our culture tends to assume that selfishness is natural, while altrusim requires an explanation. But why?

This question sprang to my mind the other day, while I was reading John Brashaw’s “In Defense of Dogs” (a book I am enjoying greatly – but that’s a different topic). I noticed a statement, made in passing, that whereas biologists do not feel the need to explain altruism in animals when it is directed towards members of the individual’s family, when this is not the case it always calls for an explanation. I get the impression that this is quite a well-established and reasonable view: when an individual helps a member of its family to survive, it is aiding the propagation of some of its genes – half when we help our offspring, one quarter when we help a sibling, one eighth when we help a first cousin, and so on. In contrast, helping a completely unrelated individual does not help the helper’s genes to propagate.

But then I thought: what if the other individual is of the same species? It does not help any of your genes, but that individual shares the same genome – the genome of your species – so you are helping your genome, and therefore your species, to survive. It would be reasonable to expect that species may have evolved whose evolutionary strategy includes altruism towards individuals of the same species, which would have given that species a competitive advantage against other species. This seems to me quite reasonable. But if we start to think that way, then we have to ask: what about helping individuals of other species? All species on Earth share the use of DNA as the gene-encoding substrate, so species that ehlp other species are contributing to the survival of DNA-based life. In fact, when you think of it, it is evident that all life on Earth is cooperating on a global scale, e.g. the plants capture CO2 and release oxygen that we breathe. While DNA-based lifeforms are not in direct competition with other forms of life, they may have been in the past, and in any case the DNA-based living Earth is always competing with the alternative, dead Earth. So again, if different species had not helped each other out perhaps there would be no life on Earth. 

So I think a more reasonable approach is to consider that there is a hierarchy of levels of organisation, and at every level cooperation is essential to make the whole possible (see figure). There are even some intermediate levels, for example oxygen-breathing lifeforms helped each other in competition with sulfur-based ones, for example. So although when you look at the nitty-gritty of individual interactions between individuals there seems to be a lot of competition going round, I think the big story of life on Earth is one of cooperation.

I think this part of a more general theme: in life, in society, and even at the microscopic level in the interactions between myriads of atoms or electrons inside materials, cooperation leads to behaviours that can reinforce themselves and survive, while pure competition leads to and “averaging out to zero”. So what is natural is coopertation and leads to what we observe -be it life on Earth or the magnetic field of a nedymium magnet. 

It is also, incidentally, a nicer way to look at the world than the victorian cut-throat tinge with which natural evolution is often described.

 


Thank you, Professor Eco

February 21, 2016

Umberto Eco has died aged 84.

There are few intellects I admired more than Eco’s. The tiny bit of his work that I had the good fortune to read shaped much of my worldview and even some of my deepest feelings.

My PhD thesis on unconventional superconductors opened with a quote from The Name of The Rose: «Nessuno ci impone di sapere, Adso. Si deve, ecco tutto, anche a costo di capire male.» I asked an Italian colleague, fellow physicist Natascia Andrenacci, to look for those sentences in her copy of the book so I could quote the original (I asked her in an email if she owned one; she explained that everyone in Italy did). I then asked a friend, Caroline Turner, to check that my English translation made sense: “No one demands that we know, Adso. We must, that is all, even at the risk of being wrong.” I had come across these sentences first in Spanish. I felt the English edition did not make them justice. I think the author of “Mouse or Rat?” would have appreciated my vicisitude.

The Name of the Rose could be intepreted as a post-post-modern parable of scientific research. As William of Baskerville explains to Adso, our theories may be wrong, but they allow us to reach a truth, described by a better theory, that we would never otherwise have reached. That truth, of course, is subject to the same relativism and so on ad infinitum. But there is something to find out, and that’s what matters.

I always thought the ideas in “Mouse or Rat?”, his collection of essays on translation, could also be adapted as a vindication of the hopefulness of science from a postmodern perspective. In Eco’s view, exactness cannot exist in translation, but loyalty and faithfulness does. Is that what we are doing when we describe the physical world: translating God’s design (speaking metaphorically, of course) into a description that could never really capture it, but might at least constitute an honest, coherent attempt? I always wondered if Eco had ever written on this subject or at least entertained similar ideas. I should have written to him to ask, but I didn’t. Now I’ve missed my chance.

Even more important to me than Eco’s ideas was the way reading him can connect us with some very basic features of what it is to be alive, and human. In Foucault’s Pendulum the main character, when he realises that all is lost for him, focuses on his young son, and imagines him having his special moment, that instant when being, place and time itself combine together to produce an intense awareness of the sensory wonderness of our world and our being sentient beings in it. He wonders what will make it for his son. Observing a little ant, maybe? Eco’s monumentally important point is that, above and beyond any Popperian, rational arguments against magical thinking and conspiracy theories like the ones pursued by the main character’s tormentors, their way of thinking misses the very point of what fascinates that “diabolical” horde: the inherent trascendnce in our being in this world. Such transcendence is not achieved by reason, be it through the (diabolical) discovery of hidden networks of conspirators or the (scientific) unveiling of fundamental laws of nature, but by raw sensory awareness and self-awareness. It’s not a thought, but a feeling.

Many years later, when my daughter was born, I wrote her a poem (as sentimental parents do) and wondered what wonders she would see today. The poem mentions a little ant as an example of what something wondrous could be for a little baby. I now realise I was channelling Eco without even noticing it.

Like Richard Feynman, Eco teaches us not just that to think deeply is fun, but that we must think deeply because it is fun.

Thank you, Professor Eco. I wish your special moment, whenever that was, and whatever it consisted of, was as eye-widening and intense as any could ever have been.


The other blog that has been keeping me away from this one…

September 21, 2011

Well over a year has passed since my last post and I think that requires an explanation. Since September 2010 I have been busy setting up a small theory outpost of the University of Kent’s Functional Materials Group at the Rutherford Appleton Laboratory. The new research group, which is part of SEPnet and of the Hubbard Theory Consortium, has its own blog (much more active than this one) at

http://blogs.kent.ac.uk/strongcorrelations

The new blog is of a rather more technical nature than this one so I will keep Condensed Matters open to post the occasional wild speculation or unfettered musing as inspiration calls.


Are high-energy physicists about to give us yet another probe?

October 17, 2009

In some recent posts I have highlighted the fact that some of the cutting-edge research in high-energy physics (HEP) is providing us with novel form of condensed matter – in particular, the quark-gluon plasma. This type of interaction between (or merging of) condensed matter and high-energy physics is new, since in the past HEP looked at process involving a few particles at a time, i.e. it was not concerned with collective states of matter or with phase diagrams.

On the other hand, there is a different short of interaction between HEP and condensed matter physics that goes a long way back, namely we owe to high-energy physicists some of the most powerful probes available of condensed matter systems. For example, the most advanced X-ray and neutron sources are based on particle accelerators (e.g. the electron and proton synchrotrons employed by Diamond and ISIS, respectively, here on the Harwell campus). Such machines ride on the back of advances in technology that were spurred by research at the frontier of particle physics some decades ago.

Now Andreas Ipp and Christoph Keitel propose that a new probe of matter may be provided by the quark-gluon itself:

Ipp, A., Keitel, C.H. & Evers, J., 2009. Yoctosecond Photon Pulses from Quark-Gluon Plasmas. Physical Review Letters, 103(15), 152301-4.

For a short summary see

Physics – The shortest known photon pulses.

The article argues that ultra-short pulses of light are emitted by the quark-gluon plasma formed in heavy-ion collisions and propose it as a probe of ultra-fast processes, such as those taking place inside the nucleus. The pulses are ~ 1 Yoctosecond = 1E-24 seconds in duration (look it up on Wikipedia). This corresponds to approximately 4 GeV. The question I ask is: what about condensed matter? Could this be useful there, too?

While all condensed matter processes are much less energetic than that, the energy of the probe need not be the energy of the excitation being probed – the energy of the probe just limits the resolution (the energy of the excitation being probed is the energy change of the photons in the pulse as they go through the sample). In that sense these ultra-short, high-energy pulses could be useful to probe excitations at much lower energies (e.g. ~ 10 meV, which is relevant for example for magnetic excitations in superconductors) but with potentially much more resolution than can be currently achieved.

The question is: are our current probes limited by their resolution? After all, what could we possibly learn that would be relevant to understand, say, a superconductor, that happens on the yoctosecond timescale? I’d love to know what people think about this.

One final though: the Yoctosecond pulses are obtained because a ys is the typical lifetime of a quark-gluon plasma (QGP). This raises the following difficulty, from the point of view of regarding the QGP itself as a condensed system and an object of study: if it only lasts for a ys, we are going to need even faster pulses to study its dynamics. In other words, if we regard the QGP as a condensed matter system, it is going to be really hard to invent the equivalents of neutron and X-ray scattering for this system. Perhaps we could use photons created in one QGP to probe another one…?


Are robots the next condensed matter?

September 23, 2009
Modular robots on the march... Is this the next condensed matter?

Modular robots on the march... Is this the next condensed matter?

Because condensed matter deals with concepts as fundamental as as scale invariance and broken symmetry, it is sometimes hard to predict where the next big condensed matter physics problem will turn up. For example (continuing from my latest post) who would have guessed twenty years ago that atomic physicists and high-energy physicists would today be furnishing some of the most interesting examples of strongly correlated matter? So it is interesting to be wild and speculate where the next big realm of condensed matter physics may lay. (After all, wild speculation is one of the things a blog may be useful for.)

In this spirit, I dare suggesting a look at modular reconfigurable robotics: robots made up of many individual, but interacting, identical elements. There are a number of groups around the world working on it. At the time of writing, there is a fairly detailed overview of the field on Wikipedia.

The Wikipedia article list a number of challenges for the future. It starts with the following (I quote):

Demonstration of a system with >1000 units. Physical demonstration of such a system will inevitably require rethinking key hardware and algorithmic issues, as well as handling noise and error.

A way to phrase this problem is to say that we want a large assembly of robots to behave like a condensed matter system, where a very large collection of individual, interacting elements (e.g. all the individual atoms in a magnetic material) conspire to produce a collective behaviour (e.g. ferromagnetism) in spit of the presence of errors and imperfections (e.g. impurities, missing atoms at indivudal lattice sites, and so on). So in some sense this problem of modular reconfigurable robotics has already been solved by Nature in condensed matter systems. Thus some important problems in modular reconfigurable robotics might be solved by looking to condensed matter for inspiration (e.g. find the conditions to achieve in the robots the equivalent of generalised rigidity).

Indeed researchers in that field are already having to draw on some elementary condensed matter concepts. See, for example, the PARC Modular Robotics website: the section on the Proteo project even has a good old-fashioned discussion of close packing structures.

Conversely, and perhaps even more interestingly (at least from a condensed matter theorist’s point of view) the robots could be used to realize new states of classical condensed matter – just as novel forms of quantum condensed matter are currently being created through chemical synthesis and in ultra-cold atom labs. Interestingly, the individual building blocks in the case of robots can be a lot more complex than in any form of condensed matter we currently know of e.g. the rules governing element-element interactions may be very complicated – for example, the interactions could be time-dependent or depend on the history of previous interactions for each individual particle (i.e. each individual robot module). It will be interesting to see whether such complexity of the individual particles will find a manifestation at the collective (macro) level or rather we will find that the beahviour of the whole always obeys simpler, emergent organisational principles. The latter is the case of, for example, a human crowd – though the interactions between individual components of a human crowd are in fact simple, while in the case of robots we might engineer them to be very complex.


Strong correlations in ultra-cold atom gases and at the RHIC – the string connection

September 17, 2009

You may remember a brief mention of Brookhaven’s Relativistic Heavy Ion Collider (RHIC) in our article on strong correlations of a couple of months ago. This month Physics World carries another article, by Barbara Jacak, that discusses that type of strongly-correlated quantum matter in a lot more detail. The new article explains how string theory can be used to connect the experiments at RHIC to others carried out on another type of strongly-correlated system: ultra-cold atomic gases. Well worth reading:
http://physicsworld.com/cws/article/indepth/40224

PS: there was also a much more technical article on strongly interacting matter (as the quark-gluon soup is now known) in Rev. Mods. Phys. a few months ago:

Colloquium: Phase diagram of strongly interacting matter
P. Braun-Munzinger and J. Wambach, Rev. Mod. Phys. 81, 1031 (2009)
http://dx.doi.org/10.1103/RevModPhys.81.1031