Effective thermodynamics for a marginal observer

Suppose you receive an email from someone who claims “here is the project of a machine that runs forever and ever and produces energy for free!”. Obviously he must be a crackpot. But he may be well-intentioned. You opt for not being rude, roll your sleeves, and put your hands into the dirt, holding the Second Law as lodestar.

Keep in mind that there are two fundamental sources of error: either he is not considering certain input currents (“hey, what about that tiny hidden cable entering your machine from the electrical power line?!”, “uh, ah, that’s just to power the “ON” LED”, “mmmhh, you sure?”), or else he is not measuring the energy input correctly (“hey, why are you using a Geiger counter to measure input voltages?!”, “well, sir, I ran out of voltmeters…”).

In other words, the observer might only have partial information about the setup, either in quantity or quality, because he has been marginalized by society (most crackpots believe they are misunderstood geniuses). Therefore we will call such observer “marginal”, which incidentally is also the word that mathematicians use when they focus on the probability of a subset of stochastic variables… In fact, our modern understanding of thermodynamics as embodied in statistical mechanics and stochastic processes is founded (and funded) on ignorance: we never really have “complete” information.
If we actually had, all energy would look alike, it would not come in “more refined” and “less refined” forms, there would not be a differentials of order/disorder (using Paul Valery’s beautiful words), and that would end thermodynamic reasoning, the energy problem, and generous research grants altogether.

Even worse, within this statistical approach we might be missing chunks of information because some parts of the system are invisible to us. But then, what warrants that  we are doing things right, and he (our correspondent) is the crackpot? Couldn’t it be the other way around? Here I would like to present some recent ideas I’ve been working on together with some collaborators on how to deal with incomplete information about the sources of dissipation of a thermodynamic system. I will do this in a quite theoretical manner, but somehow I will mimic the guidelines suggested above for debunking crackpots. My three buzzwords will be: marginal, effective, and operational.

“COMPLETE” THERMODYNAMICS: AN OUT-OF-THE-BOX VIEW

The laws of thermodynamics that I address are:

  • The good ol’ Second Law (2nd)
  • The Fluctuation-Dissipation Relation (FDR), and the Reciprocal Relation (RR) close to equilibrium
  • The more recent Fluctuation Relation (FR)1 and its corollary the Integral FR (IFR), that have been discussed on this blog in a remarkable post by Matteo Smerlak.

The list above is all in the “area of the second law”. How about the other laws? Well, thermodynamics has for long been a phenomenological science, a patchwork.  So-called Stochastic Thermodynamics is trying to put some order in it by systematically grounding thermodynamic claims in (mostly Markov) stochastic processes. But it’s not an easy task, because the different laws of thermodynamics live in somewhat different conceptual planes. And it’s not even clear if they are theorems, prescriptions, habits (a bit like in jurisprudence…2). Within Stochastic Thermodynamics, the Zeroth Law is so easy nobody cares to formulate it (I do, so stay tuned…). The Third Law: no idea, let me know. As regards the First Law (or, better, “laws”, as many as there are conserved quantities across the system/environment interface…), we will assume that all related symmetries have been exploited from the offset to boil down the description to a minimum.

1

This minimum is as follows. We identify a system that is well separated from its environment. The system evolves in time, the environment is so large that its state does not evolve within the timescales of the system3. When tracing out the environment from the description, an uncertainty falls upon the system’s evolution. We assume the system’s dynamics to be described by a stochastic Markovian process.

How exactly the system evolves and what is the relationship between system and environment will be described in more detail below. Here let us take an “out of the box” view. We resolve the environment into several reservoirs labeled by index \alpha. Each of these reservoirs is “at equilibrium” on its own (whatever that means… 4). Now, the idea is that each reservoir tries to impose “its own equilibrium” on the system, and that their competition leads to a flow of currents across the system/environment interface. Each time an amount of the reservoir’s resource crosses the interface, a “thermodynamic cost” has to be to be paid or gained (be it a chemical potential difference for a molecule to go through a membrane, or a temperature gradient for photons to be emitted/absorbed, etc.).

The fundamental quantities of stochastic thermo-dynamic modeling thus are:

  • On the “-dynamic” side: the time-integrated currents \Phi^t_\alpha, independent among themselves5. Currents are stochastic variables distributed with joint probability density

P(\{\Phi_\alpha\}_\alpha)

  • On the “thermo-” side: The so-called thermodynamic forces or “affinities”6 \mathcal{A}_\alpha  (collectively denoted \mathcal{A}). These are tunable parameters that characterize reservoir-to-reservoir gradients, and they are not stochastic. For convenience, we conventionally take them all positive.

Dissipation is quantified by the entropy production:

\sum \mathcal{A}_\alpha \Phi^t_\alpha

We are finally in the position to state the main results. Be warned that in the following expressions the exact treatment of time and its scaling would require a lot of specifications, but keep in mind that all these relations hold true in the long-time limit, and that all cumulants scale linearly with time.

  • FR: The probability of observing positive currents is exponentially favoured with respect to negative currents according to

P(\{\Phi_\alpha\}_\alpha) / P(\{-\Phi_\alpha\}_\alpha) = \exp \sum \mathcal{A}_\alpha \Phi^t_\alpha

Comment: This is not trivial, it follows from the explicit expression of the path-integral, see below.

  • IFR: The exponential of minus the entropy production is unity

\big\langle  \exp - \sum \mathcal{A}_\alpha \Phi^t_\alpha  \big\rangle_{\mathcal{A}} =1

Homework: Derive this relation from the FR in one line.

  • 2nd Law: The average entropy production is not negative

\sum \mathcal{A}_\alpha \left\langle \Phi^t_\alpha \right\rangle_{\mathcal{A}} \geq 0

Homework: Derive this relation using Jensen’s inequality.

  • Equilibrium: Average currents vanish if and only if affinities vanish:

\left\langle \Phi^t_\alpha \right\rangle_{\mathcal{A}} \equiv 0, \forall \alpha \iff  \mathcal{A}_\alpha \equiv 0, \forall \alpha

Homework: Derive this relation taking the first derivative w.r.t.  {\mathcal{A}_\alpha} of the IFR. Notice that also the average depends on the affinities.

  • S-FDR: At equilibrium, it is impossible to tell whether a current is due to a spontaneous fluctuation (quantified by its variance) or to an external perturbation (quantified by the response of its mean). In a symmetrized (S-) version:

\left.  \frac{\partial}{\partial \mathcal{A}_\alpha}\left\langle \Phi^t_{\alpha'} \right\rangle \right|_{0} + \left.  \frac{\partial}{\partial \mathcal{A}_{\alpha'}}\left\langle \Phi^t_{\alpha} \right\rangle \right|_{0} = \left. \left\langle \Phi^t_{\alpha} \Phi^t_{\alpha'} \right\rangle \right|_{0}

Homework: Derive this relation taking the mixed second derivatives w.r.t.  {\mathcal{A}_\alpha} of the IFR.

  • RR: The reciprocal response of two different currents to a perturbation of the reciprocal affinities close to equilibrium is symmetrical:

\left.  \frac{\partial}{\partial \mathcal{A}_\alpha}\left\langle \Phi^t_{\alpha'} \right\rangle \right|_{0} - \left.  \frac{\partial}{\partial \mathcal{A}_{\alpha'}}\left\langle \Phi^t_{\alpha} \right\rangle \right|_{0} = 0

Homework: Derive this relation taking the mixed second derivatives w.r.t.  {\mathcal{A}_\alpha} of the FR.

Notice the implication scheme: FR => IFR => 2nd, IFR => S-FDR, FR => RR.

“MARGINAL” THERMODYNAMICS (STILL OUT-OF-THE-BOX)

Now we assume that we can only measure a marginal subset of currents \{\Phi_\mu^t\}_\mu \subset \{\Phi_\alpha^t\}_\alpha (index \mu always has a smaller range than \alpha), distributed with joint marginal probability

P(\{\Phi_\mu\}_\mu) = \int \prod_{\alpha \neq \mu} d\Phi_\alpha \, P(\{\Phi_\alpha\}_\alpha)

2

Notice that a state where these marginal currents vanish might not be an equilibrium, because other currents might still be whirling around. We call this a stalling state.

\mathrm{stalling:} \qquad \langle \Phi_\mu \rangle \equiv 0,  \quad \forall \mu

My central question is: can we associate to these currents some effective affinity \mathcal{Q}_\mu in such a way that at least some of the results above still hold true? And, are all definitions involved just a fancy mathematical construct, or are them operational?

First the bad news: In general the FR is violated for all choices of effective affinities:

P(\{\Phi_\mu\}_\mu) / P(\{-\Phi_\mu\}_\mu) \neq \exp \sum \mathcal{Q}_\mu \Phi^t_\mu

This is not surprising and nobody would expect that. How about the IFR?

  • Marginal IFR: There are effective affinities such that

\left\langle \exp - \sum \mathcal{Q}_\mu \Phi^t_\mu \right\rangle_{\mathcal{A}} =1

Mmmhh. Yeah. Take a closer look this expression: can you see why there actually exists an infinite choice of “effective affinities” that would make that average cross 1? Which on the other hand is just a number, so who even cares? So this can’t be the point.

Fact is the IFR per se is hardly of any practical interest, as are all “asbolutes” in physics. What matters is “relatives”: in our case, response. But then we need to specify how the effective affinities depend on the “real” affinities. And here steps in a crucial technicality, whose precise argumentation is a pain. Basing on reasonable assumptions7, we demonstrate that the IFR holds for the following choice of effective affinities:

\mathcal{Q}_\mu = \mathcal{A}_\mu - \mathcal{A}^{\mathrm{stalling}}_\mu,

where \mathcal{A}^{\mathrm{stalling}} is the set of values of the affinities that make marginal currents stall. Notice that this latter formula gives an operational definition of the effective affinities that could in principle be reproduced in laboratory (just go out there and tune the tunable until everything stalls, and measure the difference). Obvsiously:

  • Stalling : Marginal currents vanish  if and only if effective affinities vanish:

\left\langle \Phi^t_\mu \right\rangle_{\mathcal{A}} \equiv 0, \forall \mu \iff \mathcal{A}_\mu \equiv 0, \forall \mu

Now, according to the inference scheme illustrated above, we can also prove that:

  •  Effective 2nd Law: The average marginal entropy production is not negative

\sum \mathcal{Q}_\mu \left\langle \Phi^t_\mu \right\rangle_{\mathcal{A}} \geq 0

  • S-FDR at stalling:

\left. \frac{\partial}{\partial \mathcal{A}_\mu}\left\langle \Phi^t_{\mu'} \right\rangle \right|_{\mathcal{A}^{\mathrm{stalling}}} + \left. \frac{\partial}{\partial \mathcal{A}_{\mu'}}\left\langle \Phi^t_{\mu} \right\rangle \right|_{\mathcal{A}^{\mathrm{stalling}}} = \left. \left\langle \Phi^t_{\mu} \Phi^t_{\mu'} \right\rangle \right|_{\mathcal{A}^{\mathrm{stalling}}}

Notice instead that the RR is gone at stalling. This is a clear-cut prediction of the theory that can be experimented with basically the same apparatuses with which response theory has been experimented so far (not that I actually know what these apparatuses are…): at stalling states, differing from equilibrium states, the S-FDR still holds, but the RR does not.

INTO THE BOX

You definitely got enough of it at this point, and you can give up here. Please
exit through the gift shop.

If you’re stubborn, let me tell you what’s inside the box. The system’s dynamics is modeled as a continuous-time, discrete configuration-space Markov “jump” process. The state space can be described by a graph G=(I, E) where I is the set of configurations, E is the set of possible transitions or “edges”, and there exists some incidence relation between edges and couples of configurations. The process is determined by the rates w_{i \gets j} of jumping from one configuration to another.

We choose these processes because they allow some nice network analysis and because the path integral is well defined! A single realization of such a process is a trajectory

\omega^t = (i_0,\tau_0) \to (i_1,\tau_1) \to \ldots \to (i_N,\tau_N)

A “Markovian jumper” waits at some configuration i_n for some time \tau_n with an exponentially decaying probability w_{i_n} \exp - w_{i_n} \tau_n with exit rate w_i = \sum_k w_{k \gets i}, then instantaneously jumps to a new configuration i_{n+1} with transition probability w_{i_{n+1} \gets {i_n}}/w_{i_n}. The overall probability density of a single trajectory is given by

P(\omega^t) = \delta \left(t - \sum_n \tau_n \right) e^{- w_{i_N}\tau_{i_N}} \prod_{n=0}^{N-1} w_{j_n \gets i_n} e^{- w_{i_n} \tau_{i_n}}

One can in principle obtain the p.d.f. of any observable defined along the trajectory by taking the marginal of this measure (though in most cases this is technically impossible). Where does this expression come from? For a formal derivation, see the very beautiful review paper by Weber and Frey, but be aware that this is what one would intuitively come up with if he had to simulate with the Gillespie algorithm.

The dynamics of the Markov process can also be described by the probability of being at some configuration i at time t, which evolves with the master equation

\dot{p}_i(t) = \sum_j \left[ w_{ij} p_j(t) - w_{ji} p_i(t) \right].

We call such probability the system’s state, and we assume that the system relaxes to a uniquely defined steady state p = \mathrm{lim}_{t \to \infty} p(t).

A time-integrated current along a single trajectory is a linear combination of the net number of jumps \#^t between configurations in the network:

\Phi^t_\alpha = \sum_{ij} C^{ij}_\alpha \left[ \#^t(i \gets j) - \#^t(j\gets i) \right]

The idea here is that one or several transitions within the system occur because of the “absorption” or the “emission” of some environmental degrees of freedom, each with different intensity. However, for the moment let us simplify the picture and require that only one transition contributes to a current, that is that there exist i_\alpha,j_\alpha such that

C^{ij}_\alpha = \delta^i_{i_\alpha} \delta^j_{j_\alpha}.

Now, what does it mean for such a set of currents to be “complete”? Here we get inspiration from Kirchhoff’s Current Law in electrical circuits: the continuity of the trajectory at each configuration of the network implies that after a sufficiently long time, cycle or loop or mesh currents completely describe the steady state. There is a standard procedure to identify a set of cycle currents: take a spanning tree T of the network; then the currents flowing along the edges E\setminus T left out from the spanning tree form a complete set.

The last ingredient you need to know are the affinities. They can be constructed as follows. Consider the Markov process on the network where the observable edges are removed G' = (I,T). Calculate the steady state of its associated master equation (p^{\mathrm{eq}}_i)_i, which is necessarily an equilibrium (since there cannot be cycle currents in a tree…). Then the affinities are given by

\mathcal{A}_\alpha = \log  w_{i_\alpha j_\alpha} p^{\mathrm{eq}}_{j_\alpha} / w_{j_\alpha i_\alpha} p^{\mathrm{eq}}_{i_\alpha}.

Now you have all that is needed to formulate the complete theory and prove the FR.

Homework: (Difficult!) With the above definitions, prove the FR.

How about the marginal theory? To define the effective affinities, take the set E_{\mathrm{mar}} = \{i_\mu j_\mu, \forall \mu\} of edges where there run observable currents. Notice that now its complement obtained by removing the observable edges, that we call the hidden edge set E_{\mathrm{hid}} = E \setminus E_{\mathrm{mar}}, is not in general a spanning tree: there might be cycles that are not accounted for by our observations. However, we can still consider the Markov process on the hidden space, and calculate its stalling steady state p^{\mathrm{st}}_i, and ta-taaa: The effective affinities are given by

\mathcal{Q}_\mu = \log w_{i_\mu j_\mu} p^{\mathrm{st}}_{j_\mu} / w_{j_\mu i_\mu} p^{\mathrm{st}}_{i_\mu}.

Proving the marginal IFR is far more complicated than the complete FR. In fact, very often in my field we will not work with the current’ probability density itself,  but we prefer to take its bidirectional Laplace transform and work with the currents’ cumulant generating function. There things take a quite different and more elegant look.

Many other questions and possibilities open up now. The most important one left open is: Can we generalize the theory the (physically relevant) case where the current is supported on several edges? For example, for a current defined like \Phi^t = 5 \Phi^t_{12} + 7 \Phi^t_{34}? Well, it depends: the theory holds provided that the stalling state is not “internally alive”, meaning that if the observable current vanishes on average, then also should \Phi^t_{12} and \Phi^t_{34} separately. This turns out to be a physically meaningful but quite strict condition.

IS ALL OF THERMODYNAMICS “EFFECTIVE”?

Let me conclude with some more of those philosophical considerations that sadly I have to leave out of papers…

Stochastic thermodynamics strongly depends on the identification of physical and information-theoretic entropies — something that I did not openly talk about, but that lurks behind the whole construction. Throughout my short experience as researcher I have been pursuing a program of “relativization” of thermodynamics, by making the role of the observer more and more evident and movable. Inspired by Einstein’s gedankenexperimenten, I also tried to make the theory operational. This program may raise eyebrows here and there: Many thermodynamicians embrace a naïve materialistic world-view whereby what only matters are “real” physical quantities like temperature, pressure, and all the rest of the information-theoretic discourse is at best mathematical speculation or a fascinating analog with no fundamental bearings.  According to some, information as a physical concept lingers alarmingly close to certain extreme postmodern claims in the social sciences that “reality” does not exist unless observed, a position deemed dangerous at times when the authoritativeness of science is threatened by all sorts of anti-scientific waves.

I think, on the contrary, that making concepts relative and effective and by summoning the observer explicitly is a laic and prudent position that serves as an antidote to radical subjectivity. The other way around, clinging to the objectivity of a preferred observer — which is implied in any materialistic interpretation of thermodynamics, e.g. by assuming that the most fundamental degrees of freedom are the positions and velocities of gas’s molecules — is the dangerous position, expecially when the role of such preferred observer is passed around from the scientist to the technician and eventually to the technocrat, who would be induced to believe there are simple technological fixes to complex social problems

How do we reconcile observer-dependency and the laws of physics? The object and the subject? On the one hand, much like the position of an object depends on the reference frame, so much so entropy and entropy production do depend on the observer and the particular apparatus that he controls or experiment he is involved with. On the other hand, much like motion is ultimately independent of position and it is agreed upon by all observers that share compatible measurement protocols, so much so the laws of thermodynamics are independent of that particular observer’s quantification of entropy and entropy production (e.g., the effective Second Law holds independently of how much the marginal observer knows of the system, if he operates according to our phenomenological protocol…). This is the case even in the every-day thermodynamics as practiced by energetic engineers et al., where there are lots of choices to gauge upon, and there is no other external warrant that the amount of dissipation being quantified is the “true” one (whatever that means…) — there can only be trust in one’s own good practices and methodology.

So in this sense, I like to think that all observers are marginal, that this effective theory  serves as a dictionary by which different observers practice and communicate thermodynamics, and that we should not revere the laws of thermodynamics as “true
idols,  but rather as tools of good scientific practice.

REFERENCES

  • M. Polettini and M. Esposito,  Effective fluctuation and response theory, arXiv:1803.03552

In this work we give the complete theory and numerous references to work of other people that was along the same lines. We employ a “spiral” approach to the presentation of the results, inspired by the pedagogical principle of Albert Baez.

  • M. Polettini and M. Esposito,  Effective thermodynamics for a marginal observer, Phys. Rev. Lett. 119, 240601 (2017), arXiv:1703.05715

This is a shorter version of the story.

  • B. Altaner, MP, and M. Esposito, Fluctuation-Dissipation Relations Far from Equilibrium, Phys. Rev. Lett. 117, 180601 (2016), arXiv:1604.0883

Early version of the story, containing the FDR results but not the full-fledged FR.

  • G. Bisker, M. Polettini, T. R. Gingrich and J. M. Horowitz, Hierarchical bounds on entropy production inferred from partial information, J. Stat. Mech. 093210 (2017), arXiv:1708.06769

Some extras.

  • M. F. Weber and E. Frey, Master equations and the theory of stochastic path integrals, Rep. Progr. Phys. 80, 046601 (2017).

Great reference if one wishes to learn about path integrals for master equation systems.

1 There are as many so-called “Fluctuation Theorems” as there are authors working on them, so I decided not to call them by any name. Furthermore, notice I prefer to distinguish between a relation (a formula) and a theorem (a line of reasoning). I lingered more on this here.

2

“Just so you know, nobody knows what energy is”. Richard Feynman.

I cannot help but mention here the beautiful book by Shapin and Schaffer Leviathan and the air-pump about the Boyle vs. Hobbes diatribe about what constitutes a  “matter of fact,” and Bruno Latour’s interpretation of it in We have never been modern. Latour argues that “modernity” is a process of separation of the human and natural spheres, and within each of these spheres a process of purification of the unit facts of knowledge and the unit facts of politics, of the object and the subject. At the same time we live in a world where these two spheres are never truly separated, a world of “hybrids” that are at the same time necessary “for all practical purposes” and unconceivable according to the myths that sustain the narration of science, of the State, and even of religion. In fact, despite these myths, we cannot conceive a scientific fact out of the contextual “network” where this fact is produced and replicated, and neither we can conceive society out of the material needs that shape it: so in  this sense “we have never been modern”, we are not quite different from all those societies that we take pleasure of studying with the tools of anthropology. Within the scientific community Latour is widely despised; probably he is also misread. While it is really difficult to see how his analysis applies to, say, high-energy physics, I find that thermodynamics and its ties to the industrial revolution perfectly embodies this tension between the natural and the artificial, the matter of fact and the matter of concern. Such great thinkers as Einstein and Ehrenfest thought of the Second Law as the only physical law that would never be replaced, and I believe this is revelatory. A second thought on the Second Law, a systematic and precise definition of all its terms and circumstances, reveals that the only formulations that make sense are those phenomenological statements such as Kelvin-Planck’s or similar, which require a lot of contingent definitions regarding the operation of the engine, while fetished and universal statements are nonsensical (such as that masterwork of confusion that is “the entropy of the Universe cannot decrease”). In this respect, it is neither a purely natural law — as the moderns argue, nor a purely social construct — as the postmodern argue. One simply has to renounce to operate this separation. While I do not have a definite answer on this problem, I like to think of the Second Law as a practice, a consistency check of the thermodynamic discourse.

3 This assumption really belongs to a time, the XIXth century, when resources were virtually infinite on planet Earth…

4 As we will see shortly, we define equilibrium as that state where there are no currents at the interface between the system and the environment, so what is the environment’s own definition of equilibrium?!

5 This because we already exploited First Law.

6 This nomenclature comes from alchemy, via chemistry (think of Goethe’s The elective affinities…), it propagated in the XXth century via De Donder and Prigogine, and eventually it is still present in language in Luxembourg because in some way we come from the “late Brussels school”.

7 Basically, we ask that the tunable parameters are environmental properties, such as temperatures, chemical potentials, etc. and not internal properties, such as the energy landscape or the activation barriers between configurations.

Future of energy and thermodynamic cycles

Yesterday the conEnergia conference on future prospects of energy consumption has taken place in the beautiful renaissance theater Bibiena of Mantova. Here a few notes on the seminars (I expand on my own intervention).

Matteo PolettiniIntroduction: energies in transformation

“In transformation” =  entropy.

Thermodynamics is the science of energy management. It grew alongside the industrial revolution, at a time when resources were virtually infinite. The infinity of resources is inbuilt in the foundations of Statistical Mechanics, the modern formulation of thermodynamics I work on, where it is assumed that some “infinite sink” of resources is present: in other words, that things thrown into the environment do not come back. In a way, thermodynamics is the cultural product of its time. As resources on planet Earth become scarce, so thermodynamics needs to evolve as well.

The title the conference organizers proposed is “from the line to the circle”. Let me delve on this.

The first law of thermodynamics states that energy is conserved. The second law states that energy’s quality is degraded (forget about the formulation ” the entropy of the Universe does not decrease”, that doesn’t make sense as it has no operational value). Rather, there is a whole collection of second laws, each peculiar to a machine or process. They usually go like: “it is impossible for a cyclic process to … as its only effect”. What fills the dots depends on the machine under consideration. For example: “to transfer heat from a cold to a hot reservoir” etc. Let us dissect this sentence. First, the second law signals an impossibility: from a practical point of view, it is to be used not to build things, but to be skeptical about things. It is the law of skepticism, almost an ethical judgement on the methodology by which we conduct our research. Second: it has to do with a cyclic process within the system; this is necessary if we want to restart the process and initiate its industrial reproduction. Third: the “to be filled” sentence always represents a “linear” non-cyclic transfer of some resources across the environment, from one reservoir to another. Finally: as its only effect. So, if we include further effects we might be able to operate the cycle in the other direction, and revert the flow through the environment, thus closing the environmental cycle. Then, it might be feasible to, say, recycle what has already been trashed. But now the newer effect (or, more typically, effects) will have opened up other noncyclic processes in the environment, and so on head so on. If we really want a so-called “circular”, or “cradle-to-cradle” economy, we need to close cycles sure*, but in doing so we need to assure that we don’t open other ones, and we resort to the one and only process that has the right to remain linear, that of the sun’s life **.

Often in energy-related news one hears “zero-emission” stuff has been built. That is always suspect. For example, the zero-emission train (the Independent https://www.independent.co.uk/news/world/europe/germany-unveils-zero-emissions-train-only-emits-steam-lower-saxony-hydrogen-powered-a7391581.html) running on hydrogen is obviously not zero emission: hydrogen on planet Earth is all burnt already, so to produce it we have to burn something the traditional way. “Zero-emission” then refers to the very “modern” principle that there are no emissions in Germany where the train will run, but on the other hand there will be lots of emissions in those countries of the third world where we use to throw our dirt, as if under the carpet.

So, as you see, each thermodynamic cycle that closes opens up one or many other cycles.

Finally, a more philosophical consideration: Now that I’m all into Bruno Latour, and in particular I suggest “We have never been modern”, I realize that the individual cycles we talk translate into what are called the pneumatic facts by Boyle, and that the interlacing of cycles are Latour’s “hybrids”. In this sense, this conference is “a celebration of hybrids…”.
Nicola ArmaroliThe Energy Transition

80% of the world energy consumption is still sustained by fossil fuels. Solar is growing fast. He proposes an interesting analysis of consumption in terms of energetic slaves, that is, how many humans would be needed to do the same thing (a concept from Ivan Illich). An airplane requires 1.6 milion slaves. These slaves are the carbon-carbon and carbon-hydrogen bonds of the hydrocarbons. People often think that energy is expensive. But that’s not true, fuel is even cheaper than water – and it includes a lot of taxes. Debate is mostly focused on electrical energy, but 25% is electricity consumption and 75% are fuels. There are at least two kinds of oils: the “easy one” of Saudi Arabia that literally pours out. And now we are moving towards the non-conventional oil. In one hour the sun gives the quantity of energy that humans use in one year. Sun is versatile.

Today the sun produces 2% of world energy. In italy 7%. photovoltaic is mostly silicium. Wind power in the world is equivalent to 150 nuclear plants. It has never happened in history that some simple transitions like this was this fast. Transportation is the main leverage for the energy transition. From harvesting 1m^2 of rapeseed for one year in one’s backyard, one runs the car 2km. From 1m^2 of a panel for one year on one’s backyard, one does 500 Km. Choices have to be technically informed by numbers.

The bottlenecks of the energy transition. Would it be possible that we all go by electric car, as regards the materials? Suppose we can all buy a Tesla S. 80 TWh of energy consumed in Italy. It’s actually very little. It’s not the problem of the amount of electricity to all go by electric car. The problem is that we would need 20 times the world extraction of Lithium, just for Italy.
Gianluca Ruggieri, Consuming less to produce better – The energy transition and us

Starts with the Mononoke princess, representing the conflict between the city and the forest [again, interesting link to the beginning of “We have never been modern” on the separation between man and nature]. The spirits of the forest fight back the city because of the use of wood. The age of wood finished when wood finished. Between the ‘700 and the ‘800 they moved to carbon, which before was considered to provide “bad smoke”, as described by Charles Dickens in Hard Times. The British cities are made around coal.

Next: Motown, the name of Detroit, the capital of the auto industry. The American cities are made around cars.

Now: Freiburg, Solarsiedlung. It’s easier to go by bike than by car. The houses are all exposed south. And you cannot move by car. The objective in Switzerland is to reduce to one third of the energy consumed today. The proposal came from a green politician, it was opposed, they a referendum was held and the pro-green policy won (citizens were more responsible than politicians). Germany has as objective the 50% of energy consumption by 2050, especially in buildings 80% less than today. In France they want to reduce nuclear by 50%.

He mentions that he has a collection of energetic scenarios built in the past and they were wrong. They are not meant for prediction, but for understanding.

Italy imports 3/4 of the energy. Energy efficiency requires a lot of human work, so it’s also virtuous from that point of view.

How do we use energy in the house. Most of the energy that we use is for heating. We disperse it through walls, windows, or ventilation. In a typical ’70s house in Italy most of the dispersion is through walls. NZEB (“nearly zero energy building”) is now the standard in Lombardy, if you start from zero you have to build it like this. For ventilation, the air from the inside pre-heats the air from the outside.

“Il futuro non è più quello di una volta”.

 

Alicia Valero Delgado, Materials for the future in the energy transition

– Thanatia and the Second Law of Thermodynamics

An hypothesis about an Earth where all concentrated energy resources have been exploited and dispersed in the crust. We have to understand and know where we are in this process. The equilibrium state of life is death. If you don’t do anything to the system it will degrade. Everything that is different from the dead environment has “exergy”, which is a measure of the quality of energy. The “exergy” or “utility” of resources allows to put everything into the same units and it allows to compare things.

An “equilibrium” approach to thermodynamics. The sun allows directly or indirectly to regenerate that which has become degraded. So the question is “Are we approaching Thanatia? And at which rate?”.

– Towards a green energy transition?

ITC <-> Gold, tin, niobium, tantalum
Biomass <-> phosphorous
Wind <-> permanent magnets Nd, Dy, Pr, Sm and Co (rare earths, critical if we want to have wind power that has little maintenance, which is crucial if we want to have the wind power offshore)
Photovoltaics <-> In, Te, Ga, Ge, As, Gd
LETs and screens: Y, Eu, Tb, In, Sn
Batteries: <-> Ni, Mn, Co (absolutely critical!), Cd, La, Ce, Li
Electric vehicles <> La, Imanes permanents

“Multicolor economy”, not green! because we are going to use a lot of the periodic table. From here to 2020, 2030, 2040 etc. exergetic analysis of the energy transition. -25% less exergy in terms of fossil fuels, and +16% exergy more in raw materials.

Conventional power plants do not need rare materials. Which is more efficient: the old light bulb (tungsten, aluminum, glass, that’s it), the fluorescent, the LED is 10X more efficient. The fluorescent was a horrible idea. The LED is good.

You have to consider the quantity in the crust, and the energy required to extract, which increases exponentially the rarest the materials will become. As regards copper, in ten years 30% copper extraction more, but 46% energy cost of extracting copper.

They have assessed supply risks from a physical/geological point of view. We defined a risk scale. High: cumulative demand 2016-2050 > availability. Medium: there is a momentary difference between supply and demand.

Very high risk: Ag, Cd, Co, Cr, Cu, ga, In, Li, Mn, Ni, Pb, Pt, Te, Zn.

Lithium availability: Hubbard-sort of peak. The peak depends on what is in the ground, and no one know exactly what it’s in the ground. And even in the most optimist assumption the peak is just a few decades away.

The case of phosphorous is also problematic, because it exists but it is localized: most of it is in Western Sahara (I didn’t know this). The green oil: it cannot be replaced, and it is absolutely necessary for agriculture.

Today, mining is between 8% and 10% of the world energy consumption.

We need to recycle more, because at the moment is really bad.

 

– Towards a circular economy?

Share, repair, etc. Circular economy for everything? How to reuse tiny microparticle in cosmetics, in paintings, in the etc. Is the cure worse of the disease? Circular economy is impossible, we call it “spiral economy” because everything gets degraded in any case.

The value of durability. We have to increase the diameter of the spirals.

It is fashionable to say. We are developing great materials through the mixture of great materials: metal mixology. We need a global assessment of how it is expensive to separate them back.

reducing consumption, dematerialization, substitution of critical raw materials, and increase of the spirals.

 
Matteo Zuin, For a carbon-free energy: research in thermonuclear fusion

“It’s important to understand that in physics we have absolutely no idea of what is energy…”

R. Feynman.

[my opinion: Energy is conserved. It’s the other way around! That which is conserved, that’s energy. It’s not a law, it’s a definition!]

[I couldn’t take notes here because of low battery.]

 

Students of the high schools

Two students from scientific high schools. Our carbon footprint.

Surface of wood surface necessary to absorb the carbon dioxide.

62% of Km is car alone. 33% in two people.

We need to consider numbers to take sensible decisions.

 

Fabio Di Menna, Energy ad food systems: waste and opportunities

The relationship between food and energy is even intrinsic to physical units. The Joule is the energy necessary to raise an apple by one meter. The calorie is necessary to heat water.

Food energy and drinkable water are three aspects that cannot be separated.

Waste: food that is thrown away but that is edible. 33% of the world production is wasted.

world BALANCE (2014) Diagram of Sanct….??? Very interesting diagram.

When we talk about energy we also need to talk about equity. OECD countries use mostly fossil, Africa mostly biomasses.

They considered a comprehensive energy balance of milk produced in Missouri USA and in Emilia-Romagna in 15 farms… We have more energy input for the industrial production of food than there is inside the food itself. They considered energy in working and packaging salad according to different branding necessities.

Digestato…
Biogas…

The problem with incentives
Marco Grasso, Climate policy and consumption-based carbon accounting

He starts saying that his argument is more theoretical, abstract, and less “sexy”. With the Paris meeting countries made some pledges declaring what they intend to do in terms of nationally determined contributions. This is contrary to the Kyoto protocol to pretend to say how countries should have done the transition, a very top-down approach. The unit measure of emissions are measured in terms of the production of the emission of those goods and services that are produced. This is often made in Taiwan, and made in China etc. 2°C is sort of the unanimously considered the boundary (without scientific arguments, a bit naive). Even in the better of hypothesis Paris brings us beyond that. Hurricanes enter the discussion. Some thinkers believe catastrophes are needed to take action. The acceptance of responsibility has slowed down the reaching the compromise, and the compromise is very modest.

What could unblock, or favor to go beyond Paris before the “global stocktake” in 2023. He proposes to pass from emission basing on production bases accounting (PBA) to consumption based accounting (CBA), there already exist databases from the second half of the ’80s (it is not a problem of measurement). The advantages would be in terms of equity (the countries that have polluted more would pay more), efficacy (it would stimulate international collaboration), and more politically doable.

An example: sharing the carbon budget. He and a coauthor published on Nature Climate Change trying to look at what would happen. We Europeans have off-shored our productions via colonialism.

 

* We should also make sure that the cycles that we open are not much bigger and expensive that the original one. Unfortunately assuming the opposite is a quite realistic attitude, as notes Fukuoka in his The one straw revolution.

** Even assuming that technologies could be invented to invert the chemical reactions that occur (for the most part) in the production of energy, and even assuming that we become so smart to produce very cheap and ecological technologies in this respect, I’m actually skeptical of the theoretical possibility of using the sun as the only source of both the energy input and the technology. If that was the case, we would have a “no-cradle-to-cradle” theorem… In this respect, it would be interesting to study wether “nature alone” (that is, that thing that was running basically up until the industrial revolution) did the whole thing just using the sun, or there was some “linear” (though minimal) consumption of earthly resources.

 

 

 

conEnergia @ Mantova

conEnergia is a Festival on the future perspectives of energy taking place in these days in Mantova. I contributed to the organization of several activities taking place at this Festival, including movies screenings, laboratories with high-school students, and a scientific conference that will take place next Friday in the beautiful Teatro Bibiena, see the program below. I will try to live-blog from the conference.

 

FROM THE LINE TO THE CIRCLE: WHICH ENERGETIC TRANSITION?

Mantova, Teatro Bibiena, Friday April 20th, 2018, 9 a.m. – 4 p.m.

 

Francesco Dugoni (direttore AGIRE). The project “conEnergia”

Matteo Polettini (University of Luxembourg). Introduction – Energies in transformation

At a first sight, the energetic discourse regards the harvesting of some specific resources, which are usually categorized as either fossil or “renewable”. However, every form of energy is degraded, and its regeneration depends on external factors: closing a thermodynamic cycle requires to open up another one, each with its own “externality” (which are never actually external, given that they remain on planet Earth). Thus, at a second sight, all energies are in mutual relation, often through several intermediate passages: photo-electric conversion is in relation to mechano-chemical extraction of the rare metals needed for the construction of solar panels; metabolic energy is in relation with the fossil energy sustaining the agricultural industry; the finiteness of resources of planet Earth is in relation with climate change. Finally, the great “cycle” of energetic policies conditions, and is conditioned, by local and global practices of energy management.

Matteo Polettini is research in Theoretical Physics at the University of Luxembourg, where he works on statistical mechanics and on the thermodynamics of irreversible processes.

 

Nicola Armaroli (ISOF CNR). The energy transition

We all use energy in each and every moment of the day, with an abundance never experienced in the history of humankind; this entails a considerable impact on theenvironment, climate, economy and international relations. My discussion will briefly illustrate the global energy picture, highlighting how the formidable expansion of renewable technologies indicates that the phasing out of traditional energy resources has started. However, the energy transition will be e a long and difficult process, requiring remarkable technological, economic and social progress, among which (a) a rational use ofthe limited mineral resources of “spaceship Earth”, which are necessary to fabricate theconverters and accumulators of renewable fluxes, (b) technologies that produce much more energy than that necessary to make them available, (c) a reduction of the primary consumption in the richest countries, (d) a transition from a linear to a circular economy, (e) a strong reduction of inequalities in the access to energy across the world.

Nicola Armaroli is a CNR director or research. He studies new materials for the conversion of solar energy, luminescence and catalysis.

 

Gianluca Ruggieri (University of Insubria). Consuming less to produce better – The energy transition and us

The renewable revolution proceeds faster than most favorable previsions. To complete it though will require an equally important effort to reduce the primary consumptions in all developed economies. Less energy we consume, the easier it is to produce it. The process has started but it needs a major boost. Which are the objectives that posed by the biggest European countries? What will these objectives imply in the fields of motility and building? What is the energetic intensity and how is it evolving in time? How can we be sure that the technologies that we use can effectively bring to a reduction of absolute consumes (and not just to a mimetization?) In all of this, which role can have every single citizen with his personal action or with collective activities “from below”?

Gianluca Ruggeri, environmental engineer, is researcher in Environmental Technical Physics at the University of Insubria.

 

Matteo Zuin (University of Padova – CNR). Sustainable thermonuclear fusion research for ultimate carbon-free energy

Thermonuclear fusion, the reaction that powers the Sun and the stars, is a potential source of safe, non-carbon emitting and virtually limitless energy. Scientists from all over the world have moved a step closer to achieving sustainable nuclear fusion. Harnessing fusion’s power is the goal of the ITER experiment, which is under construction in the southern France as the result of an international collaboration, including the European Union, the USA, China, Japan, India, Korea and Russia. ITER been designed as the key experimental step between today’s fusion research machines and tomorrow’s fusion power plants. The talk will introduce the basic concepts about the way plasmas, gases which can be ten times hotter than the sun, are produced and controlled in the laboratory and will describe the recent achievements in fusion research. The relevant role of Italy will be discussed.

Matteo Zuin has a master degree in Physics and a Ph.D. in Energetics at the University of Padova. He is researcher at CNR, working on the physics of Controlled Thermonuclear Fusion with Magnetic Confinement at the RFX experiment in Padova.

 

Alicia Valero Delgado (Fundatiòn CIRCE, University of Saragoza). Materials for the future in the energy transition

Decarbonizing world economies and thereby avoiding a 2ºC global average temperature increase implies the urgent adoption of the so called “green technologies”. Their deployment will mean a renovation of the energy sector toward using renewable sources and zero emission transport technologies. This renovation will require a huge amount of raw materials some of them considered to have high supply risks. This talk will cover the problems associated with resources supply risk for different low carbon energy technologies, including the new developments of solar photovoltaics, wind energy, CSP, biomass and biodiesel and the electric vehicle.

Dr. Alicia Valero Delgado is senior researcher at the Research Centre for Energy Resources and Consumption (CIRCE – Institute) and lecturer at the University of Zaragoza. Her more than ten years research activity has been focused on the identification of resource efficiency measures and the application of thermodynamics in the evaluation of resource depletion, subject from which she has received four international awards. Author of over 50 research papers and co-author of her renown book: Thanatia: the destiny of the Earth’s mineral resources.

 

Marco Grasso (Università degli Studi di Milano-Bicocca). Climate policy and consumption-based carbon accounting

The history of climate policy is long and awkward. A possible way to increase the success of climate policy is to use consumption-based carbon accounting. This accounting basis is, in fact, more effective, fair, and undemanding than the traditional production based one.

Marco Grasso is associate professor of geographical economy at the University of Milan-Bicocca. He works on the politics of climate change, with particular attention to the aspects of mitigation and adaptation, to the role of the oil industry and on the gonvernance of geo-engeneering.

 

L’Idée fixe

Some sparse quotes taken out of Paul Valéry, L’Idée fixe ou Deux Hommes à la mer (1932). Some I will translate in English, some I will comment, some I will leave as are. Full French text is available here.

The incipit is a piece of perfection, describing what we might call today a “depressive episode”. I report it as is:

J’étais en proie à de grands tourments : quelques pensées très actives et très aiguës me gâtaient tout le reste de l’esprit et du monde. Rien ne pouvait me distraire de mon mal que je n’y revinsse plus éperdument. Il s’y ajoutait l’amertume et l’humiliation de me sentir vaincu par des choses mentales, c’est-à-dire faites pour l’oubli. L’espèce de douleur qui a une pensée pour une cause apparente entretient cette pensée même ; et par là, s’engendre,s’éternise, se renforce elle-même. Davantage : elle se perfectionne en quelque manière ; se fait toujours plus subtile, plus habile, plus puissante, plus inventive, plus inattaquable. Une pensée qui torture un homme échappe aux conditions de la pensée ; devient un autre, un parasite.

J’avais beau essayer de reprendre l’égalité de mon âme, et de réduire enfin des idées à l’état de pures idées, ce n’était qu’un instant d’effort suivi de peines plus profondes. Vainement j’observais que ni le chagrin, ni la colère, ni ce poids énorme sur La poitrine, ni ce cœur empoigné, n’étaient des conséquences nécessaires de quelques images : Un autre, me disais-je, qui les verrait en moi, n’en serait point ému… Dans trois ans, me disais-je encore, ces mêmes fantômes n’auront plus de force… Et je trouvais en moi le désir insensé de faire par l’esprit en quelques instants ce que trois ans de vie eussent peut-être fait. Mais comment produire du temps ?

Et comment détruire l’absurde, — que nous choyons et cultivons quand il nous est délicieux ?

Je ne sais ce qui me gardait des grands remèdes… Je me bornai aux moindres : le travail et le mouvement. Je me traitai l’intellect et le corps en tyran, avec violence et inconstance. Je leur donnai des exercices difficiles : c’était faire en petit ce que fait l’humanité par ses recherches et ses spéculations : elle approfondit pour ne pas voir. Mais je me lassais promptement de mes problèmes volontaires. Leur objet indirect ruinait tout à coup leur objet direct. Je ne parvenais point à tromper mon appétit de chagrins et d’angoisse : la substitution ne se faisait pas.

The rest of the story is a dialogue. There are many passages worth mentioning, but I prefer to only focus on those that I can somehow relate to research and my own experience of it.

On the activity of research:

— Oui Monsieur ! Je développe : j’ai le mal de l’activité ! Je ne puis, je ne sais ne rien faire… Demeurer deux minutes sans idées, sans paroles, sans actes utiles… Alors, je transporte en un coin désert ces accessoires, symboles évidents de la vacance de l’esprit. Ils ordonnent l’immobilité, ils prescrivent les stations de longue et nulle durée.

[…]

— Vous voulez dire que plus on trouve, plus on cherche ; et plus on cherche, plus on trouve.

— C’est cela. Il me semble parfois qu’entre la recherche et la découverte il s’est produit une relation comparable à celle qui s’institue entre la drogue et l’intoxiqué.

On order and disorder:

[…] concédez-vous que les mots Ordre et Désordre correspondent à quelque chose ?

— A quelque chose de tout à fait relatif.

 “— Do you concede that the words Order and Disorder correspond to something? — To something relative as a matter of fact”. This connects well to my criticism of entropy: if it is order, whose order is it? Myself and my son don’t have the same perception of how tidy is his room.

La puissance du moderne est fondée sur « l’objectivité ». Mais à y regarder de plus près, on trouve que c’est… l’objectivité même qui est puissante, — et non l’homme même. Il devient instrument, — esclave, — de ce qu’il a trouvé ou forgé : une manière de voir.

“Modern power is founded on “objectivity”. But looking at it closer, one finds that… is objectivity itself to be powerful, — not humans themselves. They become instruments, — slaves, — of what they found or forged: a way of seeing.” This passage can be put in relation with lots of other thinkers, from Marx to Illich. In an automated world (he writes: “De plus en plus fort, de plus en plus grand, de plus en plus vite, de plus en plus inhumain, — ce sont des formules d’automatisme…”), mankind is used by its instruments, it becomes an instrument of the blind presumed “objectivity” of the system.

— […] Dire que nous ne savons rien de rien sur cette illustre et inconcevable propriété…

— Rien… C’est beaucoup dire. On voit que vous ne lisez pas beaucoup… Il y a des bibliothèques sur la question.

— C’est bien ce que je veux dire en disant que nous ne savons rien.

“— […] Considering that we know absolutely nothing  about this illustrious and inconceivable property… — Nothing… It’s a bit too much. I can see that you don’t read much… There are entire libraries on the question. — That’s precisely what I mean by saying we know nothing.”

— Vous ne tenez pas compte du travail. II me semble que l’esprit tend à passer du désordre à l’ordre… Ou, si vous le préférez, d’un certain désordre-pour-soi, à un certain ordre-pour-soi… Il travaille, en quelque sorte, en sens contraire de la transformation qui s’opère par les machines, lesquelles changent une énergie plus ordonnée en énergie moins ordonnée…

— Hum…

— Ce n’est qu’une image grossière… Je reviens à l’esprit… Pour qu’il opère lui aussi, sa transformation caractéristique, il faut bien lui fournir… du désordre !

— C’est immense, ce que vous dites.

— Dame…

— Ce sont des énormités.

— Et il prend son désordre où il le trouve. En lui, autour de lui, partout… Il lui faut une différence Ordre-Désordre, pour fonctionner, comme il faut une différence thermique à une machine, à un phénomène quelconque !… Mais je vous répète que la comparaison est…

— Fausse.

— Non !… Oui… Soit !…

The last lines: “— [The spirit] takes disorder from where it finds it. Inside itself, around itself, everywhere… To function,  it needs a  difference of Order-Disorder, just like a machine or any phenomenon needs a thermal difference to work!… But let me repeat to you that this comparison is…  — False. — No!… Yes… Be it!…

C’est qu’une idée ne peut pas être fixe. Peut-être fixe (si quelque chose peut l’être) ce qui n’est pas idée. Une idée est un changement, — ou plutôt, un mode de changement, — et même le mode le plus discontinu du changement… Tenez. Point de théorie. Essayez un peu de fixer une idée… Je vais chronométrer. Mais c’est inutile ! Une idée est un moyen, ou un signal detransformation, — qui agit plus ou moins sur l’ensemble de l’être. Mais rien ne dure dans l’esprit. Je vous défie d’y arrêter quoi que ce soit. Tout y est transitif… Mais presque tout y est renouvelable.

“Fact is an idea cannot be fixed. It can only be fixed (if anything can be) what is not an idea. An idea is changement, — or either, a mode of changement, —  the more discontinuous mode of changement… [etc.]”

— Eh bien, qui sait si l’Univers

— Oh ! Oh !…

— En admettant, bien entendu, que ce mot ait un sens… qui résiste à l’examen.

— Pourquoi pas ?

— Ou du moins, que nous puissions qualifier ce mot, le faire entrer dans une proposition…

— Mais pourquoi pas ?

— Comment voulez-vous que le Tout soit représenté par une image ou par une idée quelconque ? Le Tout ne peut avoir de figure semblable.

— Croyez— vous ?

“—Well, who knows if the Universe… —  Oh! oh!… — Admitting, of course, that his words has any sense… that resists to an examination. — Why? — Or at least, that we could qualify this word, put it inside a proposition… —  But why? —  How would you domand that the Whole is represented by an image or by any idea? The Whole cannot have a similar image. —  You think so?” This connects well to my criticism of the Second Law of Thermodynamics as “the entropy of the universe does not decrease”, which makes no sense to me (I will come back to this at some point).

Blackfoots’ language and physics

I just realized by chance that a person by the name David Peat died last year. I have never met him on person, and I only know of him what the Internet has to offer me, so I won’t spend useless words, you can make your own idea.

The reason why I pay this small tribute to his memory is that I once read with very much interest and without prejudice his book  Blackfoot Physics, a personal recollection of his encounter with the Blackfoots and a reflection on the world-views of Western Science and of Native Americans. The book was extremely well-written and persuasive, and it revealed a sensible soul. Although it is nowhere close to the standards of academic rigour I usually prefer, still I found it a quite honest recount and a commendable take on the processes of knowledge, a theme that I’m getting more and more sensible about.

Today I went back to one paper that summarizes his thought:

F. D. Peat, Blackfoot Physics and European Minds, Futures 29, pp. 563-573 (1997).

I find it a remarkable paper. I will report some of the sentences that I like best, and sometimes I will comment on them. I perfectly know that this practice is pure cherry-picking, and that many of his claims throughout the paper might not withstand a deeper examination. But I’m becoming more and more sympathetic to Paul Valery’s motto about what “humanity does with its researches and speculations: it deepens to not see” [L’Idée fixe ou Deux Hommes à la mer (1932)].

“Time, the theologicians had argued, belongs to God but now it became secularized through the practice of usury. Banking is about buying time and setting time aside.”

In this passage he is trying to argue for a specific era when time and space were separated. I’m not interested in that, but I like the idea that banking is a way to secularize time, to quantify, buy and sell it. It resonates with many of the considerations about debt and credit I found in David Graeber’s Dept: the first 5000 years.

“matter and spirit became fragmented one from the other and a participatory reality was transformed into scientific objectivity”

In my talk in Berlin I quoted Wheeler: “All things physical are information-theoretic in origin and this is a participatory universe…. Observer participancy gives rise to information; and information gives rise to physics.”. (apparently Feynman said of Wheeler: “Some people think that Wheeler’s gotten crazy in his later years, but he’s always been crazy!”). Interesting that the word “participatory” appears here as well, it might well be that there is an historical connection between the two.

“It is to ask if an ethincal and moral dimension can be added to our science and technology and if supposed objectivity can be tempered through participation.”

I like “supposed” objectivity.

“Not only do they speak with rocks and trees, they are also able to converse with that which remains invisible to us, a world of what could be variously called spirits, or powers, or simply energies. However, these forces are not the occupants of a mystical or abstract domain, they remain an essential aspect of the natural, material world.”

This passage might be tough for any scientist. A few years ago, when I heard the word “energy” coming from the mouths of mystics or yogi or astrologists etc. or all that crowd I would almost faint. Now, even though I don’t give an ounce more credit to these people, I’ve come to realize that we scientists don’t own words. Furthermore, in a framework of processes, these “spirits” should not be considered as something “existing” for real like ghosts in spirited houses. “Spirits” are the manifestations of the incompressible complexity of certain processes. Also our imaginary world as theoretical physicists is haunted by such figures: consider for example the experimentalist-who-reads-our-papers-and-considers-making-an-experiment-out-of-them, that mythological figure to whom we dedicate our prayers at the end of our writings…

“How can anything be preserved from change? The answer lies in participation within the flux by means of acts of renewal”

As a thermodynamician, I like this idea of renewal. After all thermodynamics is the science of cyclic processes.

“An expression of the Blackfoot’s relationship to a reality of rocks, trees, animals, and energies is expressed within what many Native Americans call ‘a map in the head’. This map is a way of knowing where one is in relationship to the land, its history, society and all the living being s of nature.”

I love this passage, the more so the the more I realize that the “westernization” of our human functions brings us to outsource many mental faculties to external toys and tools. An obvious example is the sense of orienteering, which with the advent of geolocalization is completely lost.

“Knowledge is no mere collection of facts but something that one grows towards.”

Our schools and faculties instead often teach mere collections of facts to people who don’t give a shit any longer.

“Our physical reality is that of objects in interaction with one another: nouns linked by verbs […] How eagerly do we build categories and concepts, how literally do we take our “language games”, how easily do we become in empty philosophical argument.”

As epigraph of another of his papers, The Role of Language in Science, he reports an interesting sentence by David Hume: “Nothing is more usual than for philosophers to encroach on the province of grammarians, and to engage in disputes of words, while they imagine they are handling controversies of the deepest importance and concern” (this reminds me a lot of all the disputes in thermodynamics about what is entropy, what is temperature, and all that plethora of thermodynamic potentials etc.)

“It is not the intention of this essay to argue that we should abandon the Western world-view and become Blackfoot over night. Rather it is to suggest that it would be useful for us to examine our metaphysics in the light of that of another society”.

I strongly advocate for an ethnoanthropology of the scientific community, of its myths and rites. One of those myths is certainly that of objectivity.

“While other problems may certainly arise, this sort of trap is not present within a language where the verb takes the centre stage. Within Blackfoot all is movement, process and transformation. Nouns as objects emerge in a secondary way through the modification of verbs. To them the English language is a straight-jacket which forces their minds into a world of objects, categories and restrictive logic”.

This was the original motivation to come back to this paper. I love the idea that the Blackfoot had a more naturalistic language focused on processes rather than objects. Unfortunately, this claim is not supported here by a serious analysis. But I did manage to find a better reference:

P. Bakker, Algoquian verb structure: Plains Cree, LOT Occasional Series 5 (2006): 3-27.

Some quotes:

“Cree is a typical polysynthetic language [i.e. words are made of several morphemes that often cannot appear alone] in the sense that almost all of the grammatical information is given in the verb, and very little in the noun. This means that verbs are frequent and also morphologically complex.”

“Verbs contain most of the information. It contains obligatory reference to grammatical roles and number of its arguments (subject, direct and indirect object), and optionally also several valency-changing affixes (causative, applicative, detransitivizer, passive), gender-changing suffixes (from animate to inanimate, and the reverse), plus adverbial modifiers, tense, mood, aspect, Aktionsart, discourse markers, and further also incorporated nouns, classifiers, and diminutive suffixes.

Somewhere in other readings (probably from Howard Zinn’s recount of the “discovery” of the Americas) I have read that allegedly the fact that the structure of language was so different between Europeans and Native Americans made so that it was easy for Europeans to “buy” their land off them for nothing, because Native Americans did not even conceive of the possibility of the land to be “owned”. But I’ve also heard contrary opinions on this thesis, so I’ll have to dig this up more in depth.

 

Ph.D. @ Uni Lux on thermodynamics of computation

There will soon be an official opening for a thematic Ph.D. position at the Complex Systems and Statistical Mechanics group of the University of Luxembourg, where Prof. Massimiliano Esposito is Principal Investigator and I am research associate. I will be the Ph.D.’s advisor. The project is entitled “Accuracy and energetic efficiency of computation in the post-Moore-law era: a Stochastic Thermodynamics approach” (see short description below). We would like the candidate to start in June 2018. We are looking for a student with a strong background in mathematics and theoretical physics, and with some programming skills. Students interested should submit their application directly to me, including their curriculum, complete with marks from their bachelor and master degrees, a motivation letter, and possibly a short presentation letter by their master thesis advisor.

PROJECT DESCRIPTION

The process of miniaturization of the microprocessor, which has sustained the tremendous spreading of digital technologies, is slowing down and might eventually come to a halt as it meets its fundamental thermodynamic limits, both in the process of computation and in the process of transportation of information. At the macroscopic level, keeping within an energetic budget is crucial to avoid over-heating at room temperature of personal devices; furthermore, the energy expenditure to maintain major data centers and High Performance Computing facilities cool should remain a small share of the world’s energy consumption. At the microscopic level, as the electronic components become smaller, the operating voltages become comparable to the random voltage generated by thermal noise (the environment), which produces false bit flips and makes computation inaccurate. Therefore, keeping within a fixed energy budget is at the same time a formidable constraint and the occasion to venture into new research directions that demand a better integration between all levels involved in the process, from the algorithmic one, to the technological, to the architecture of the network. In this respect, many recent lines of research propose a slow-down of the computational task and to trade energetic feasibility with accuracy (whenever the tasks need not be too precise). As infinitely-fast computation is accurate but expensive, and infinitely-slow computation is cheap but completely unreliable, there exists a (class of) optimums in between. The main objective of this project is to find and characterize this class. The physical theory that allows to study the trade-off between velocity, thermodynamic efficiency, and accuracy is Stochastic Thermodynamics, which was recently formalized into a complete theory but has among its milestones the work by Johnson and Nyquist on the analysis of electrical noise in circuits. The project’s goal is to develop a set of tools that will allow to make claims about optimal conditions for the “next switch” (any technology that might replace the transistor with a slower technology), or for the next integration step. The project will be based on the mathematics of Langevin systems applied to the electrical elements and circuits that are fairly representative of IT technologies.