Science and Faith – The Arts of the Unknown

I spent this morning singing a Sunday service at St. George’s Church in Borough. An odd occupation for a scientist perhaps, especially given the high profile of several atheist researchers! Yet a large number of scientists see no contradiction between faith and science. In fact, my Christian faith is only deepened by my fascination with the natural world.

Picture a scientist. Chances are you’ve already got in your mind a geeky, rational person, calibrating a precise experiment or poring over a dry mathematical formula! As with any stereotype, it has it’s merits. But it misses a vital quality in research – imagination.

To succeed as a scientist, you must be creative above all else. It’s no use just learning experimental techniques or memorising formulae. Every new idea must necessarily start off as a fantasy. Great painters are not merely lauded for their 10,000 hours of practice with a paintbrush. It is their capacity to conceive and relay vivid scenes which ensures their place in history. And so it is with science.

So why are scientists seen as cold and calculating and exact, rather than passionate and original? The problem lies in education. While young children are encouraged to express themselves in Literacy, Numeracy is all too often a trudge through tedious and predictable sums. In “arts” subjects, questions are a magical tool enabling discussion, debate and opinion. In “sciences” they merely distinguish right from wrong.

After 15 years of schooling, no wonder the stereotype is embedded! As a teenager, I very nearly ditched the sciences in favour of subjects where expression was free and original arguments rewarded. I’m eternally thankful to my teachers, parents and bookshelf for convincing me that the curriculum was utterly unrepresentative of real science.

So what’s to be done. For any budding scientists out there, your best bet is to read some books. Not your school textbooks – chances are they are dull as ditchwater and require no creative input at all. I mean books written by real life mathematicians, physicists, biologists… These will give you an insight into the imagination that drives research, the contentious debates and the lively exchanges of ideas.

You might not understand everything, but that’s the whole point – science is about the unknown, just as much as art or faith. It is exactly this point which we must evangelise again and again. Perhaps then fewer people will write negative reviews criticising science for being complex, poetic and beautiful.

As a wider society, we can take action too! We must demand better science teaching from a young age. Curricula should emphasise problem solving over knowledge, ideas over techniques and originality over regurgitation. This is already the mantra for many traditionally “artistic” discplines. It must be the battle cry for scientists also!

A better approach to science would democratize opportunity for the next generation. No longer will the relative creativity of girls be arbitrarily punished – an approach which can only discourage women from entering science in the long run. No longer will there be a tech skills gap threatening to undermine the thriving software industry. The UK has a uniquely privileged scientific pedigree. For future equality, economy and diversity, we must use it.

In the service this morning Fr Jonathan Sedgwick talked of the danger of applying scientific laws to the world at large. The concepts of “cause and effect” and “zero sum games” may well work in vacuo, but they are artificial and burdensome when applied to interpersonal relationships. Quite right – as Christians we must question these human rules, and look for a divine inspiration to guide our lives!

But this is also precisely what we must do as scientists. A good scientist always questions their models, constantly listening for the voice of intuition. For science – like our own existence – is ever changing. And it’s our job to search for the way, the truth and the life.

My thanks to Margaret Widdess, who prepared me for confirmation two years ago at St. Catharine’s College, Cambridge and with whom I first talked deeply about the infinity of science and faith.

Why does feedback hurt sometimes?


Research is hard. And not for the reasons you might expect! Sure, my daily life involves equations which look impenetrable to the layman. But by the time you’ve spent years studying them, they aren’t so terrifying!

The real difficulty in research is psychological. The natural state for a scientist is failure – most ideas simply do not succeed! Developing the resilience, maturity and sheer bloody mindedness to just keep on plugging away is a vital but tough skill.

This letter, written by an experienced academic to her PhD student is a wonderfully candid account of the minefield of academic criticism, both professional and personal. What’s more, it lays bare some important coping strategies – I certainly wish I’d read it before embarking on my PhD.

Above all, this letter is an admission of humanity. As researchers, we face huge challenges in our careers. But the very personal process of responding to them is precisely what makes us better scientists, and perhaps even improves us as people.

Originally posted on The Thesis Whisperer:

This letter was written by an experienced academic at ANU to her PhD student, who had just presented his research to a review panel and was still licking her wounds.

The student sent it to me and I thought it was a great response I asked the academic in question, and the student who received it, if I could publish it. I wish all of us could have such nuanced and thoughtfu feedback during the PhD. I hope you enjoy it.

Screen Shot 2014-02-05 at 7.27.05 PMA letter to…My PhD student after her upgradeWell you did it. You got your upgrade. But from the look on your face I could tell you thought it was a hollow victory. The professors did their job and put the boot in. I remember seeing that look in the mirror after my own viva. Why does a win in academia always have the sting of defeat?

Yeah, it’s a…

View original 1,120 more words

Mathematica for Physicists

I’ve just finished writing a lecture course for SEPnet, a consortium of leading research universities in the South East of Britain. The course comprises a series of webcasts introducing Mathematica – check it out here!

Although the course starts from the basics, I hope it’ll be useful to researchers at all levels of academia. Rather than focussing on computations, I relay the philosophy of Mathematica. This uncovers some tips, tricks and style maxims which even experienced users might not have encountered.

I ought to particularly thank the Mathematica Summer School for inspiring this project, and demonstrating that Mathematica is so much more than just another programming language. If you’re a theorist who uses computer algebra on a daily basis, I thoroughly recommend you come along to the next edition of the school in September.

Using Thunderbird Client with Office 365

I’ve just wasted a good half hour trying to migrate my email to an Office365 SMTP server. It seems that QMUL have decided to discontinue their in-house email server, but have not provided sufficient details about the new settings needed for email clients.

So here they are, in case anyone else runs into difficulties.

SMTP server :
Username : <your-id>
Port : 587 (not the default)
Encryption : STARTTLS (not SSL/TLS)

I imagine that similar settings should work for other institutions which have moved to an Office365 system.

T-duality and Isometries of Spacetime

I’ve just been to an excellent seminar on Double Field Theory by its co-creator, Chris Hull. You may know that string theory exhibits a meta-symmetry called T-duality. More precisely, it’s equivalent to put closed strings on circles of radius R and 1/R.

This is the simplest version of T-duality, when spacetime has no background fields. Now suppose we turn on the Kalb-Ramond field B. This is just an excitation of the string which generalizes electromagnetic potential.

This has the effect of making T-duality more complicated. In fact it promotes the R\to 1/R symmetry to O(d,d;\mathbb{Z}) where d is the dimension of your torus. Importantly for this to work, we must choose a B field which is constant in the compact directions, otherwise we lose the isometries that gave us T-duality in the first place.

Under this T-duality, the B field and G metric get mixed up. This can have dramatic consequences for the underlying geometry! In particular our new metric may not patch together by diffeomorphisms on our spacetime. Similarly our new Kalb-Ramond field B may not patch together via diffeomorphisms and gauge transformations. We call such strange backgrounds non-geometric.

To express this more succintly, let’s package diffeomorphisms and gauge transformations together under the name generalized diffeomorphisms. We can now say that T-duality does not respect the patching conditions of generalized diffeomorphisms. Put another way, the O(d,d) group does not embed within the group of generalized diffeomorphisms of our spacetime!

This lack of geometry is rather irritating. We physicists tend to like to picture things, and T-duality has just ruined our intuition! But here’s where Double Field Theory comes in. The idea is to double the coordinates of your compact space, so that O(d,d) transformations just become rotations! Now T-duality clearly embeds within generalized diffeomorphisms and geometry has returned.

All this complexity got me thinking about an easier problem – what do we mean by an isometry in a theory with background fields? In vacuum isometries are defined as diffeomorphisms which preserve the metric. Infinitesimally these are generated by Killing vector fields, defined to obey the equation

\displaystyle \mathcal{L}_K g=0

Now suppose you add in background fields, in the form of an energy-momentum tensor T. If we want a Killing vector K to generate an overall symmetry then we’d better have

\displaystyle \mathcal{L}_K T=0

In fact this equation follows from the last one through Einstein’s equations. If your metric solves gravity with background fields, then any isometry of the metric automatically preserves the energy momentum tensor. This is known as the matter collineation theorem.

But hang on, the energy momentum tensor doesn’t capture all the dynamics of a background field. Working with a Kalb-Ramond field for instance, it’s the potential B which is the important quantity. So if we want our Killing vector field to be a symmetry of the full system we must also have

\displaystyle \mathcal{L}_K B=0

at least up to a gauge transformation of B. Visually if we have a magnetic field pointing upwards everywhere then our symmetry diffeomorphism had better not twist it round!

So from a physical perspective, we should really view background fields as an integral part of spacetime geometry. It’s then natural to combine fields with the metric to create a generalized metric. A cute observation perhaps, but it’s not immediately useful!

Here’s where T-duality joins the party. The extended objects of string theory (and their low energy descriptions in supergravity) possess duality symmetries which exchange pieces of the generalized metric. So in a stringy world it’s simplest to work with the generalized metric as a whole.

And that brings us full circle. Double Field Theory exactly manifests the duality symmetries of the generalized metric! Not only is this mathematically helpful, it’s also an important conceptual step on the road to unification via strings. If that road exists.

Integrating Differentials in Thermodynamics

“My bad!”, he said.

I’ve just realised I made a mistake when teaching my statistical physics course last term. Fortunately it was a minor and careless maths mistake, rather than any lack of physics clarity. But it’s time to set the record straight!

Often in thermodynamics you will derive equations in differential form. For example, you might be given some equations of state and asked to derive the entropy of a system using the first law

\displaystyle dE = TdS - pdV

My error pertained to exactly such a situation. My students had derived the equation

\displaystyle dS = (V/E)^{1/2}dE+(E/V)^{1/2}dV

and were asked to integrate this up to find S. Naively you simply integrate each separately and add the answers. But of course this is wrong! Or more precisely this is only correct if you get the limits of integration exactly right.

Let’s return to my cryptic comment about limits of integration later, and for now I’ll recap the correct way to go about the problem. There are four steps.

1. Rewrite it as a system of partial DEs

This is easy – we just have

\displaystyle \partial S/\partial E = (V/E)^{1/2} \textrm{ and } \partial S / \partial V = (E/V)^{1/2}

2. Integrate w.r.t. E adding an integration function g(V)

Again we do what it says on the tin, namely

\displaystyle S(E,V) = 2 (EV)^{1/2} + g(V)

3. Substitute in the \partial S/\partial V equation to derive an ODE for g

We get dG/dV = 0 in this case, easy as.

4. Solve this ODE and write down the full answer

Immediately we know that g is just a constant function, so we can write

\displaystyle S(E,V) = 2 (EV)^{1/2} + \textrm{const}

Contrast this with the wrong answer from naively integrating up and adding each term. This would have produced 4(EV)^{1/2}, a factor of 2 out!

So what of my mysterious comment about limits above. Well, because dS is an exact differential, we know that we can integrate it over any path and will get the same answer. This path independence is an important reason that the entropy is a genuine physical quantity, whereas there’s no absolute notion of heat. In particular we can find S by integrating along the x' axis to x' = x then in the y' direction from (x',y')=(x,0) to (x',y')=(x,y).

Mathematically this looks like

\displaystyle S(E,V) = \int_{(0,0)}^{(E,V)} dS = \int_{(0,0)}^{(E,0)}(V'/E')^{1/2}dE' + \int_{(E,0)}^{(E,V)}(E'/V')^{1/2}dV'

The first integral now gives 0 since V=0 along the E axis. The second term gives the correct answer S(E,V) = 2(EV)^{1/2} as required.

In case you want a third way to solve this problem correctly, check out this webpage which proves another means of integrating differentials correctly!

So there you have it – your health warning for today. Take care when integrating your differentials!

Bibliographies and The arXiv

I’m currently writing up my first paper! The hope is that my collaborators and I will release the paper in the next couple of months. When we do, it’ll go on the arXiv – a publically accessible preprint server.

This open-access policy is adopted pretty much universally throughout mathematics and theoretical physics. I think it’s extremely good for science to be freely accessible to all. There’s still a place for journals, allowing research to be ranked by quality and rigorously peer reviewed. But the arXiv is vital in maintaining the pace of research, particularly in hot topic areas.

Every piece of work on the arXiv gets its own unique identifier. I rather like codes, so I tend to remember these numbers for my favourite papers. Just typing the number into Google search immediately takes you to the relevant document.

My current paper draft is peppered with arXiv numbers referring to important papers we need to cite. When we come to making a bibliography I’ll need to convert these into a standard form. Technically this involves making a BibTex file, and referring to it in my typesetting program.

I thought this would take ages, but it turns out that there’s an online Easter Egg solving the problem in a flash. Inspire HEP is a database of physics papers, providing all the metadata you could ever need including ready formatted BibTex. And it even has a feature which automatically generates a bibliography for you – check it out!

If you’re writing up your first paper and this tip helped you out, do drop me a line in the comments! And to the curators of arXiv and Inspire HEP – a huge thank you from me and the whole physics community.

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