Category Archives: Third level

Summer hols; summer school, swimming and that book

You must be finished for the summer? Like most academics, I get asked this question every day in summer, usually by village acquaintances convinced that college closes the day the students finish their exams.

Some lecturers in the Institutes of Technology do indeed take off from June 20th to September 1st; that is their right, given the heavy teaching load during termtime. However, for those of us who try to keep up the research, the summer months are the time to get something done, just like our colleagues in the universities.

For me, this is no chore  – the sheer bliss of being able to do quiet research without classes, meetings, staff interactions and all the rest of it. Very restful. Also, we’re having a serious heatwave in Ireland this month and I’m happy to escape to the cool, quiet office every day. So I plug away happily during the day and treat myself to a swim in my village in the evenings..

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Tide’s in on Lawlor’s Strand in Dunmore East

Actually, I did give some ‘cameo’ lectures this week and last, to our summer school. We have a very nice bunch of engineering, computing and business students visiting from Kiel in Germany, and I had fun trying to condense my climate science course down to a one-hour presentation for each group. I haven’t given short presentations on climate before, it was very satisfying to prepare (see here for a copy of the talk)  The other thing I noticed was that students from the continent always seem to be very mature, polite and interested. I must look into an exchange sometime, do they have Erasmus for staff?

My main task this summer is to finish my little book on cosmology. It’s based on a course I have taught for some years and it’s been a lot of fun to write. Now I’m finding that it’s one thing to write a book and quite another to get it published! Still, I have plenty of time now to be writing book proposals and writing to publishers. In the meantime, I look forward to a swim in the sea everyday after work and a walk into the village. It’s funny to live in a village where others come for summer holidays!

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Tide’s out on Lawlor’s Strand in Dunmore East

Update

Unfortunately it’s so warm, we’re beginning to get quite a few jellyfish. Hope it cools down a little next week!

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Day II at Oxford

Today was the second day of the  Cosmology and Quantum Foundations  conference, a symposium that forms part of the  Establishing the Philosophy of Cosmology project at Cambridge and Oxford.

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The workshop this morning started with a fascinating talk by Douglas Spolyar  on a model of cosmic inflation that predicts that inflation could happen at relatively low energies. The big advantage of such models that they are testable at the TeV energies, i.e., at accelerators such as the LHC; I need to read the paper before I comment further, but all the talks will soon be available on the conference website.

Laura Mersini then gave a talk on evidence for the multiverse post-Planck. This was a discussion of her thesis that the multiverse should in principle be detectable in the cosmic microwave background because of the phenomena of quantum entanglement and decoherence. She then discussed how in her view the Planck data offers support for the model in terms of the cold spot, the dark flow and other effects. It was a good thorough lecture and I understood a lot more than I did at the Cambridge conference on the philosophy of cosmology last March.  Of course, not all cosmologists agree with her thesis and there was plenty of lively discussion from the audience – as an experimentalist, I really like the way theoreticians constantly challenge each other  during their talks, it’s very interactive!

In the afternoon , it was back to the conference proper for ‘Probability and the multiverse: an Everettian view’, the second installment of Simon Saunder’s discussion of the many-worlds interpretation of quantum theory. I found this a lot more challenging than Monday’s talk, I really need to brush up on my reading on many-worlds. Max Tegmark then gave a talk on ‘Thermodynamics, information and consciousness in a quantum multiverse’, a discussion that was  full of interesting insights and provocative ideas. A central theme of his is that entropy does not always increase, but can in fact decrease on observation. I have heard this idea before but I’ve never been clear whether it is an argument that pertains to entropy as a state of information about a system, or whether it is literally true of physical entropy.  I wanted to ask this at question time, and how one might test the hypothesis,  but time ran out.

[Update: I asked Max this question over coffee. I think the answer is yes to physical entropy and he suggested an experiment that could test the idea; unfortunately, I understood about 5% of what he said, I need to read up on this!]

The last speaker of the day was Carlo Rovelli, who spoke on a new interpretation of quantum theory known as the relationary view, a hypothesis  he put forward in the 1990s. This interpretation of qt  imports a lot of ideas from special relativity, in particular applying the idea of the reference frame of the observer to the measurement problem. Thus, instead of talking about wavefunctions that collapse into one state or another, one has to consider that measurements of systems are made relative to another system – it is the relation between the systems that counts. It was fascinating to hear a description of this intriguing new idea from its creator, and tomorrow he will explain how the new theory gives a description of  quantum gravity. [Writing this, I seem to remember that one of Schrodinger's own objections to the notion of collapsing wavefunctions involved the problem of observations of the same object from different reference frames, must look this up]

After all that, it was time for the conference dinner. I was lucky enough to be at the same table as Carlo, who is also  the author of the highly regarded book ‘The First Scientist: Anaximander and His Legacy’ and we had a great discussion on the history of science. I have never met a physicist who is not interested in the history of our subject – how things were found out is almost as interesting as the things themselves!

As a bonus, the an after-dinner talk was given by Max Tegmark who posed an intriguing question; what if mathematics is a useful way of describing nature simply because nature *is* mathematics? This question was  first raised by Pythagoras, and Max gave an extremely interesting talk on the subject. So much so that I finally realised who he reminds me of – Richard Feynman!

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I had a quick walk under the Bridge of Sighs before dinner

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Filed under Cosmology (general), Third level

A day in the life

There is a day-in-the life profile of me in today’s Irish Times, Ireland’s newspaper of record. I’m very pleased with it, I like the title  – Labs, lectures and luring young people into scence  – and the accompanying photo, it looks like I’m about to burst into song! This is a weekly series where an academic describes their working week, so I give a day-to-day description of the challenge of balancing teaching and research at my college Waterford Institute of Technology in Ireland.

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Is this person singing?

There is quite  a lot of discussion in Ireland at the moment concerning the role of  institutes of technology vs that of universities. I quite like the two-tier system – the institutes function like polytechnics and tend to be smaller and offer more practical programmes than the universities. However, WIT is something of an anomaly – because it  is the only third level college in a largeish city and surrounding area, it has been functioning rather like a university for many years (i.e. has a very broad range of programmes, quite high entry points and is reasonably research-active). The college is currently being considered for technological university status, but many commentators oppose the idea of an upgrade – there are fears of a domino effect amongst the other 12 institutes, giving Ireland far too many universities.

It’s hard to know the best solution but I’m not complaining – I like the broad teaching portfolio of the IoTs, and there is a lot to be said for a college where you do research if you want to, not because you have to!

Update

I had originally said that the institutes cater for a ‘slightly lower level of student’. Oops! This is simply not true in the case of WIT, given the entry points for many of the courses I teach, apologies Jamie and Susie. Again, I think the points are a reflection of the fact that WIT has been functioning rather like a university simply because of where it is.

Comments on the article are on the Irish Times page

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Resistors in series and parallel

In the last post, we saw that for many materials, the electric current I through a device is proportional to the voltage V applied to it, and inversely proportional its resistance, i.e. I = V/R (Ohm’s law). If there is more than one device (or resistor) in a circuit, the current through each also depends on how the resistors are connected, i.e., whether they are connected in series or in parallel.

In a series circuit (below), the resistors are connected one after the other (just as in a TV series, one watches one episode after another). The same current runs through each device since there is no alternative path or branch, i.e.  I = I1 = I2. From V = IR, we see the voltage across each device will be different; in fact, the largest voltage drop will be across the largest resistance (just as the largest energy drop occurs across the largest waterfall in a river). The total voltage in a series circuit is the sum of the individual voltages, i.e. V = V1+V2. As you might expect, the total resistance (or load) of the circuit is the simply the sum of the individual resistances, R = R1 + R2.

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Series circuit: the current is the same in each lamp while there may be a different voltage drop across each (V = V1+V2 +V3)

On the other hand, resistors in a circuit can be connected in parallel (see below). In this case, each device is connected directly to the terminals of the voltage source and therefore experiences the same voltage (V = V1=V2). Since I = V/R , there will be a different current through each device (unless they happen to be of equal resistance) .The total current in a parallel circuit is the sum of the individual currents, i.e. I = I1+I2. A strange aspect of parallel circuits is that the total resistance of the circuit is lowered as you add in more devices (1/R = 1/r1 + 1/r2). The physical reason is that you are increasing the number of alternate paths the current can take.

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Parallel circuit: the voltage is the same across each lamp but the currents may be different (I = I1+I2)

Confusing? The simple rule is that in a series circuit, the current is everywhere the same because there are no branches. On the other hand, devices connected in parallel see an identical voltage. In everyday circuits, electrical devices such as kettles, TVs and computers are connected in parallel to each other because it is safer if each device sees the same voltage source; it also turns out to be more efficient from the point of view of power consumption (an AC voltage is used, more on this later).

In the lab, circuits often contain some devices connected in series, others in parallel. In order to calculate the current through a given device, redraw the circuit with any resistors in parallel replaced with the equivalent resistance in series, and analyse the resulting series circuit.

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Problem

Assuming a resistance of 100 Ohms for each of the resistors in the combination circuit above, calculate the total resistance of the circuit. If a DC voltage of 12 V is applied, calculate the current in the circuit. (Ans: 133 Ω, 0.09 A)

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End of semester

This week is one of my favourites in the college timetable. The teaching semester finished last Friday and the hapless students are now starting their Christmas exams. It’s time to empty out the teaching briefcase and catch up on research…

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Examtime in college

I recently compiled a list of this semseter’s research and outreach and was pleasantly surprised – three conference presentations, two academic papers and eight public lectures , not to mention a couple of science articles and book reviews in The Irish Times (see here for presentations and here for articles).

All of this is on top of an 18-hour teaching week, which adds up to a lot of late nights. I’ve been arguing for years that the workload in the Institutes of Technology should be more flexible; it’s very difficult to do any meaningful research if you’re teaching 18 hours a week. Another challenge is that most lecturers in the IoT sector are 3-4 to an office, with consequent staff interactions, phone calls and students coming to the door. As a result, a great many lecturers simply stop doing research, which is a terrible waste and hardly ideal for a college that teaches to degree level and beyond. I often think that, far from enhancing ‘productivity’, work practices in the IoT sector mitigate strongly against good teaching and research at third level.

In my case, I stay in college most evenings until 9 pm. That said, I enjoy the research – as I say to my students, if you find a job you truly like, you’ll never work a day in your life!

I’m particularly pleased with my recent paper on the discovery of the expanding universe. It’s my first foray into the history of cosmology, and it has already got quite a bit of attention,  thanks to a very nice conference in Arizona. I very nearly didn’t go to this conference because of teaching commitments; now I’m glad I did as it was a lot of fun and the paper has opened quite a few doors. These days, I turn down far more opportunities than I accept, it may finally be time to consider an academic move.

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Slipher’s telescope at the Lowell Observatory in Flagstaff, Arizona

Update

Meanwhile, rumours continue to circulate in the media concerning the prospect of our college being turned into a technological university. This would certainly be a welcome development, especially if it meant reduced teaching for those engaged in research, but I’d be quite surprised. WIT has been very successful at attracting research funding in certain areas, but research activity per academic is quite low in our college in comparison with the university sector. I don’t see how we could qualify as a university without bringing in quite a lot of new research-active staff , a buy-in for which there is no money whatsoever; hopefully I’m wrong on this.

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September conference: origins of the expanding universe

A conference next month will celebrate the pioneering work of the American astronomer Vesto Slipher. On September 13-15th, the Lowell Observatory in Flagstaff, Arizona, will host the conference The Origins of the Expanding Universe to commemmorate the hundredth anniversary of Slipher’s measurements of the motion of the distant nebulae; see here for the conference website.

As readers of this blog will know, Slipher observed that the light from many of the distant nebulae was redshifted, i.e. shifted to lower frequency than normal. This was the first  indication that the distant nebulae are moving away at significant speed and it was an important hint that some nebulae are in fact distinct galaxies far beyond our own Milky Way (see cosmology 101 section). A few years later, Edwin Hubble combined Slipher’s redshift results with his own measurements of distance to establish that there is a linear relation between the distance to a galaxy and its rate of recession; the relation became known as Hubble’s law although it probably should be called the Hubble/Slipher law.

The Hubble/Slipher discovery of the recession of the galaxies  was a key step along the road to the discovery of the expanding universe, but the two are not quite the same thing; for the latter, one needs to situate the phenomenon in the context of the general theory of relativity (according to relativity, the galaxies appear to be moving away from one another because space is expanding). The Belgian physicist Georges Lemaitre was the first to make the connection between the relativistic universe and the observed recession of the galaxies, although his contribution is often overlooked. A major thrust of the conference is to explore exactly such distinctions; looking at the lineup, it looks like an intriguing mixture of cosmologists, astronomers and historians.

All this is highly relevant to my yet-to-be-completed book so after a long, wet summer at WIT, I’m off to sunny Arizona next month!  My own talk is titled ‘Who discovered the expanding universe?’ and I intend to compare and contrast the contributions of various pioneers such as Slipher, Hubble, Humason, Friedmann and Lemaitre. You can see a list of speakers and abstracts for the talks here.

Many thanks to Peter Coles of In the Dark for drawing the conference to my attention.

Update

Going on holiday just as classes start back? Nice job – Ed.

Sigh. I haven’t had a day off all summer and this is not a holiday.

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Filed under Astronomy, Cosmology (general), Third level

O’Raifeartaigh Conference in Munich

I’m in Munich this weekend, at a physics conference in honour of my late father. The 2012 O’Raifeartaigh Conference is taking place in Munich’s Ludwig Maximilians Universität (LMU) and there are speakers here from Harvard, MIT, Stanford, the University of Tokyo, the Niels Bohr Institute (DK), the Eugene Wigner Institute (HN) and the Dublin Institute for Advanced Studies.

It sounds rather grand, but such memorial conferences are a good way for researchers who work in related fields to meet and present their latest work to each other. Many of the speakers worked with Dad at one stage or another and I think he would be very pleased to be remembered in this way. There are also some really sharp young scholars here and he would have liked that too. It’s the third memorial conference in Lochlainn’s memory, see here for the programme and other details.

Munich itself is fantastic – the university is right in the middle of the city and the neighbourhood is full of bookshops, coffee-houses, museums and beer gardens. The teaching term is not yet finished in Germany so there are students everywhere (don’t tell Minister Quinn!). In fact, I have never seen so many bicycles and bookshops in one place. The conference talks are in the University’s Arnold –Sommerfeld Centre for Theoretical Physics and the building has a Museum for Modern Art on one side and a music conservatoire or Musik Hochshule down the block. I could get used to this.

LMU University Munich (Main Entrance)

Lochlainn’s work concerned the use of mathematical symmetry methods to describe the physics of the elementary particles. Throughout his career at the Dublin Institute for Advanced Studies, he was considered a leading expert in the field. He is probably best known for his contributions to a radical theory known as ‘supersymmetry’, a theory that is currently being tested at the Large Hadron Collider at CERN. You can read more on his career by clicking on the tab Lochlainn on the top of the page.

There are some great talks here although some are are far beyond the comprehension of yours truly (an experimentalist). As always, I’m impressed by the style of presentation in theoretical physics; there are no polite powerpoint lectures here, but chalk-and-blackboard sessions with searching questions from the audience every few minutes. ‘‘Does that function even have a ground state?’, a speaker was asked within the first two minutes of his talk. ‘‘Well, it doesn’t in anti-deSitter space, but I hope to convince you that it does in deSitter space”, was the response. Answers to the frequent questions are tackled at the board until everyone in the room is satisfied. No-one gets away with anything here, from the youngest postdoc to the most eminent physicist. I think it’s a style of presentation that helps both lecturer and audience and I wish the humanities would adopt it – my pet hate is listening politely to a philosopher or historian for an hour before one gets to question a statement made in the first three minutes.

I gave a short talk myself on Friday. This was a ‘life-in-science’ presentation where I used pictures of people and places that influenced Lochlainn during his career: from his early work on general relativity with JL Synge  at the Dublin Institute for Advances Studies to his work on quantum field theory with Walter Heitler at the University of Zurich, from his use of group theory to prove his famous no-go theorem at Syracuse University in New York State to his work on the history of gauge theory at L’Institut des Hautes Etudes in Paris. I was worried I might have got some things wrong (e.g. “No, that work was completely incidental!’’), but thankfully it didn’t happen. In fact, I think the audience enjoyed the presentation as many of them had known the people and places mentioned at firsthand. You can find the photos and slides I used here.

Update

The conference is over today so Mum and I took an open bus tour of Munich. I find this a great way to get to know any city and it didn’t disappoint. Munich may not be as large as Berlin or Hamburg, but it is the capital of Bavaria and is an extremely impressive city. I’m amazed by the huge number of parks, wide boulevards and splendid buildings – clearly, it was did not suffer as much as so many other German cities from bombing in the war. This is one of the great privileges of being an academic – you get to see the most interesting places, all in the line of work.

The ‘heroes’ monument on Leopoldstrasse

And finally

On the way back to the hotel, I was intrigued to see a huge banner draped over the main university entrance; the legend’ STRINGS 2012′ is leaving the whole city in no doubt that a major conference on string theory is about to take place here! Such a civilised country..

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