PhD Opportunity in Theoretical Astrophysics at Maynooth!

Posting this again because the deadline (31st January) is coming up fast….

The Department of Theoretical Physics at Maynooth University invites applications for a PhD in Theoretical Astrophysics starting in September 2023. The successful applicant will work in the group led by Dr. John Regan on a project examining the formation processes of massive black holes in the early Universe. Massive black holes populate the centres of all massive galaxies and are now also observed in both the centres and in off-centre locations in less massive dwarf galaxies.

For more details and instructions on how to apply, see here.

PhD Opportunity in Theoretical Astrophysics at Maynooth!

The Department of Theoretical Physics at Maynooth University invites applications for a PhD in Theoretical Astrophysics starting in September 2023. The successful applicant will work in the group led by Dr. John Regan on a project examining the formation processes of massive black holes in the early Universe. Massive black holes populate the centres of all massive galaxies and are now also observed in both the centres and in off-centre locations in less massive dwarf galaxies.

For more details and instructions on how to apply, see here.

A Question of the Past

I was tidying up some old files earlier today and came across some old examination papers, including those I took for my final examinations in Part II of the Natural Sciences Tripos in 1985. There were six of these, in the space of three consecutive days…

I picked one of the questions to share here because it covers similar ground to my current (!) Advanced Electromagnetism module for final-year students in Maynooth. Sorry it’s a bit grubby!

It’s been a long time since I took my finals and I’d largely forgotten what the format was. The question above was taken from Paper II which consisted of nine questions altogether in three Sections, A (Solid State Physics), B (Statistical Physics) and C (Electromagnetism, from which Q9 above was taken; I think the course was actually called Electrodynamics & Relativity). The examination was 3 hours in duration and students were asked to answer four questions, including one from each Section. That means each question would be expected to take about 45 minutes.

Looking at the paper in general and the above question in particular, a number of things sprang to mind about differences between then in Cambridge and now in Maynooth:

1. Our theoretical physics papers in Maynooth are 2 hours in duration in which time students are to answer four questions, so that the questions are a bit shorter – 30 minutes each rather than 45.
2. Our papers are also on a single subject rather than a composite of several; we typically don’t offer the students choice; my Advanced Electromagnetism paper has four questions and students have to answer all four for full marks.
3. The questions on the old Tripos papers are less structured. There is no indication of the marks allocated to each part of the question in the question above.
4. As far as I can recall there was no formula booklet back in 1985, though there was a sheet of physical constants. My Advanced Electromagnetism examination this year comes with a couple of pages of useful formulae from vector calculus and key equations in EM theory. One might argue that the old Cambridge papers relied rather more on memory (especially when you take into account that everything was in the space of three days).
5. Back to Question 9, it is true that this along with the other Electromagnetism questions is at a similar level to what I have been teaching this Semester. If I recall correctly the relevant course in Cambridge was of 24 lectures, the same length as the course I’m teaching this year.
6. Students taking my course should know how to do both parts of Question 9 without too much difficulty.

On the final point, the easiest way to tackle this sort of problem is to do what the question says: determine the electric and magnetic potentials, derive the electric and magnetic fields from them, then work out the Poynting vector quantifying the energy flux. The part of this that survives in the far-field limit gives you the radiated power then – Bob’s your Uncle – the answer is basically the Larmor Formula which is ubiquitous in problems of this type. The case of an oscillating dipole is a standard derivation but this method works for any time-varying source, as long as you remember to include the retarded potentials if it’s not periodic.

Had I been writing this question for a modern exam I think I would at very least have ended the first part with “Show that the radiated power is…” and then given the formula, so that it could be used for the second part even if a student could not derive it.

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A Day of Computing

Last Semester, Thursday was what I optimistically called a “Research Day” (on the basis that I had no teaching on it). This Semester it’s one of my busiest teaching days, with lecturing in the morning and a lab session in the afternoon, both for Computational Physics.

For most of the last two years I’ve been delivering the lectures and running the lab remotely, but now that we’re back teaching face-to-face I gave the lecture in person and was in the lab with the class for this afternoon’s session. I’ve got about twice as many students this year as last year swill be running two lab sessions (one next Tuesday repeating the material from the Thursday one, and so on throughout the term).

Running the lab remotely worked reasonably well because Python is available to download for free and works on a standard Windows-based PC. In the lab however we use a Linux (Ubuntu) system, which gives the students the chance to try a different operating system (and one which is for many purposes better than Windows).

It’s good to be back running the computing laboratory class in person but I was a bit nervous this morning because since I last did it that way the machines we have in our laboratory have all been upgraded to a new operating system and have a new (and very different) version of Python (3.9 versus the now obsolete 2.7). I’ve been around long enough to realize that things can go wrong in such situations, so I warned the class during this morning’s lecture that there might be teething troubles. Sure enough we had quite a few technical glitches but, to be honest, it it could have been a lot worse. Next Tuesday’s lab should be a bit less stressful as we’ve fixed a few of the things that went wrong.

So, by no means a disaster, but a busy and quite stressful day. Time to go home and relax.

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Boards of Examination

We’ve at last staggered to the end of a week dominated by Examination matters. For myself that consisted of preliminary Examination Boards for Theoretical Physics and Engineering (for which we teach modules in Engineering Mathematics) followed by Final Examination Boards in both subjects with External Examiners present. Those final meetings both took place today so it’s been a particularly busy end of the week.

That’s not quite the end of the examinations business for the academic year, however, as we have the Final Final Examination Board in about ten days’ time. That is when marks from all Departments come together to determine the final results for students who are taking degrees in combinations of subjects. We have quite a number doing Joint Honours with Mathematics, for example. It does add an extra level to the process, but I think that’s a price worth paying for the flexibility we offer to students.

This final Examination Board takes place on 23rd June and students will get their marks a couple of days later on 25th June. Even that won’t be the end, because some students will be taking repeat examinations in August, but at least it signals a gap in the assessment cycle during which we can hopefully think of other things for a while.

Obviously I’m not going to comment on the marks for individual students but nobody will be surprised to hear that the Covid-19 pandemic has obviously had a big impact on some. It also had an impact on our External Examiner for Theoretical Physics who actually caught Covid-19 recently and became quite ill. Thankfully she is now feeling better and well enough to join us remotely today.

The Repeat Examination period takes place in August and will again be conducted remotely but hopefully the 1st Semester examinations next year will be under more normal circumstances. It’s not so much that I’m worried that our online examinations are somehow inappropriate, it’s just that it does take far longer to mark them than paper examinations and this year it has been extremely tight getting everything ready for the deadline by which marks must be committed to our central system (which is Monday 14th June).

Anyway, we’ve now done the job so I have an opportunity to thank all the staff in Theoretical Physics for their hard work and diligence!

Now it’s definitely wine o’clock.

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Remote Exam Time Again

It’s Friday 14th May 2021 which means that it’s the first day of the Summer examination period here in Maynooth, so let me begin by sending my best wishes to everyone taking examinations today and over the next few weeks, wherever you are. It’s a lovely morning in Maynooth. It seems to be a law of Nature that examinations always take place when the weather outside is nice.

For readers elsewhere in the world, full-time undergraduate students at Maynooth what is called 60 “credits” in a year, usually split into two semesters of thirty credits each. This is usually split into 5-credit modules with an examination in each module at the end of each semester. Projects, and other continuously-assessed work do not involve a written examination, but the system means that a typical student will have at least 5 written examination papers in January and at least another 5 in May.  This is very similar to the system in most UK universities that I am aware of except that a full year’s work over there is 120 credits so there’s a conversion factor of 2:1. A 5-credit module in Ireland would be a 10-credit module in the United Kingdom, for example, but otherwise the system is similar.

Each examination is usually of two hours’ duration. We’ve kept that length after moving examinations online, although students are given extra time to scan and upload their answers. The question papers themselves have been slightly adapted online use by having much less “bookwork”. Generally these assessments are unsupervised and students are allowed to consult notes and textbooks so there is little point in asking them to copy out standard derivations and formulae. That means we can concentrate on the problem-solving aspects of theoretical physics, which are the most interesting bits (and perhaps the most challenging).

One big difference between our examinations in Theoretical Physics in Maynooth and those at other institutions I’ve taught at in the UK is that most of the papers here offer no choice of questions to be answered. Elsewhere  it is quite common to find a choice of two or three questions from four or five on the paper.

One  advantage of our system is that it makes it much harder for students to question-spot in the hope that they can get a good grade by only revising a fraction of the syllabus. If they’re well designed, two long questions can cover quite a lot of the syllabus for a module, which they have to in order to test all the learning outcomes. To accomplish this, questions can be split into parts that may be linked to each other to a greater or lesser extent to explore the connections between different ideas, but also sufficiently separate that a student who can’t do one part can still have a go at others. With such a paper, however, it is a  dangerous strategy for a student to focus only on selected parts of the material in order to pass.

As an examiner, the Maynooth style of examination also has the advantage that you don’t have to worry too much if one question turns out to be harder than the others. That can matter if different students attempt different questions, but not if everyone has to do everything.

But it’s not just the number of questions that’s important, it’s the duration. I’ve never felt that it was even remotely sensible for undergraduate physics examinations to be a speed test, which was often the case when I was a student. Why the need for time pressure? It’s better to be correct than to be fast, I think. I always try to set examination questions that could be done inside two hours by a student who knew the material, including plenty of time for checking so that even a student who made a mistake would have time to correct it and get the right answer. If a student does poorly in this style of examination it will be because they haven’t prepared well enough rather than because they weren’t fast enough.

My first examination is this afternoon. The subject is (3rd Year) Computational Physics. This is an unusual module as a majority of the marks (60%) come from continuous assessment in the form of four class tests (20% altogether) and a mini-project (40%). The exam is a theory paper concerned with such topics as accuracy and stability. There are two questions on the paper, both of them compulsory. Next week there is my (4th year) Advanced Electromagnetism paper with four questions, again all compulsory. Obviously I’ll have to wait to see how the students do.

In the meantime here are some tips for students

1. Try to get a good night’s sleep before the examination!
2. Be ready well before the start and try to ensure you won’t be disturbed for the duration.
3. If you’re doing an unsupervised examination, download the paper and any supplementary material needed  at the start to avoid problems if you get disconnected.
4. Read the entire paper before starting to answer any questions. In particular, make sure you are aware of any supplementary information, formulae, etc, given in the rubric or at the end.
5. Start off by tackling the question you are most confident about answering, even if it’s not Question 1. This will help settle any nerves.
6. Don’t rush! Students often lose marks by making careless errors. Check all your numerical results on your calculator at least twice and remember to put the units!
7. Show your working! Especially in an unsupervised examination you need to convince the examiner that you actually did the problem rather than looking up the answer on the net somewhere.
8. Don’t panic! You’re not expected to answer everything perfectly. A first-class mark is anything over 70%, so don’t worry if there are bits you can’t do. If you get stuck on a part of a question, don’t waste too much time on it (especially if it’s just a few marks). Just leave it and move on. You can always come back to it later.
9. Try to finish the paper at the assigned time, i.e. use the upload time for uploading rather than doing more work. There is always the chance that you might run out of time for upload if you’re rushing right at the end.
10. If you’re scanning and uploading answers, check that you have submitted everything you intended to. I have had several examples of missing pages over the last year…

Anyway, once again, good luck and best wishes!

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Theorists and Experimentalists in Physics

Regular readers of his blog (Sid and Doris Bonkers) will know that here at Maynooth University there are two Physics departments, one the Department of Theoretical Physics (of which I am a Faculty member) and the other the Department of Experimental Physics. These two units are in the same building but have so far have been largely separate in terms of teaching and research; Experimental Physics (EP) is somewhat larger in terms of staff and student numbers than Theoretical Physics (TP).

For instance, when students enter on our General Science degree programme they have to choose four subjects in the first year, including Mathematics (much as I did when I did my Natural Sciences degree at Cambridge back in the day). Picking `double physics’ (i.e. Experimental Physics and Theoretical Physics) uses up two of those choices, whereas Physics was a single choice in the first year of my degree. In the second year of this programme students do three subjects so can continue with both Theoretical and Experimental Physics (and another) , as they can in Year 3 where they do two subjects, and in Year 4 where they can do a single Major in either TP or EP or a double Major doing a bit of both.

To confuse matters still further, the Department of Theoretical Physics only changed its name from the Department of Mathematical Physics relatively recently and some of our documentation still carries that title. Quite often I get asked what’s the difference between Theoretical Physics and Mathematical Physics? As far as Maynooth is concerned we basically use those terms interchangeably and, although it might appear a little confusing at first, having both terms scattered around our webpages means that Google searches for both `Mathematical Physics’ and `Theoretical Physics’ will find us.

The Wikipedia page for Theoretical Physics begins

Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena.

This is what Wikipedia says about Experimental Physics:

Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and observations, such as the Cavendish experiment, to more complicated ones, such as the Large Hadron Collider.

I count myself as a theoretical physicist (that’s what I did in Part II at Cambridge, anyway) though I do work a lot with data and many of the researchers in my discipline (cosmology) actually work at the interface between theory and experiment, so the distinction between theorists and experimentalists is perhaps not a very useful one.

As a matter of fact I think there’s a good case for theoretical physicists to have at least some experience of practical experimental work. There are two reasons for this:

1. to understand about errors in measurement and how to treat them properly using statistical methods;
2. to learn how easy it is to break expensive laboratory equipment.

In the past during Open Days I have asked the audience of prospective physics students if they could name a famous physicist. Most popular among the responses were the names you would have guessed: Einstein, Hawking, Feynman, Dirac, Newton, Schrodinger, and some perhaps less familiar names such as Leonard Susskind and Brian Greene. Every single one of these is (or was) a theorist of some kind. This is confirmed by the fact that many potential students mention similar names in the personal statements they write in support of their university applications. For better or worse, it seems that to some potential students at least Physics largely means Theoretical (or Mathematical) Physics.

Although it is probably good for our recruitment that there are so many high-profile theoretical physicists, it probably says more about how little the general public knows about what physics actually is and how it really works. No doubt there are many prospective students who are primarily drawn to laboratory work just as there are many drawn to theoretical calculations. But there are probably others whose interests encompass both. For me the important thing is the interplay between theory and experiment (or observation), as it is in that aspect where the whole exceeds the sum of the parts.

Anyway, this year we’ve been thinking very hard about bringing about closer cooperation between the two Physics Departments at Maynooth. It remains to be seen precisely what form that closer cooperation will take but I think it’s a good idea in principle. In fact in the Open Day at Maynooth coming up on Saturday 24th April there will, for the first time ever, be a joint talk by the Departments of Theoretical Physics and Experimental Physics. I’m looking forward to seeing how that goes!

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Teaching after Covid

I know it’s a Business lecture, but at least there is a periodic table on the wall to remind students of the time when Universities used to care about science.

Near the end of a planning meeting this morning I was asked to give my thoughts about any long-term impacts of the Covid-19 pandemic on teaching and/or research. That also echoed a discussion I had with staff in the Department of Theoretical Physics on Teams a while ago, which touched on the same question.

My own view in general is that although we find ourselves constantly saying things like “When we get back to normal…” I think we have to accept that the pandemic is going to change many things irreversibly. We’re going to have to get used to new ways of working in both teaching and research. Some changes will be made to make financial savings owing to loss of income over however long the pandemic lasts, and some of those will no doubt be painful and sad. Others will be opportunities created by us learning how to do things differently and a number of these could be very positive, if we seize the initiative and make the most of them.

One specific thing in the latter category is that Maynooth University installed a system of lecture capture to help deliver teaching when access to campus was restricted (as it is now). The hardware and software installed is fairly basic and isn’t by any means perfect, but it has worked pretty well. The main problem is that the cameras that have been installed are very limited webcams and are not capable of capturing, e.g. a blackboard.

One thing I hope will happen in the long term is that we include lecture capture as a routine way of augment students’ learning. That will require additional investment in infrastructure, but I think it would be well worth it.

Some years ago I blogged about this at another institution, which had facilities allow lecturers to record videos of their own lectures which are then made available for students to view online.

This is of course very beneficial for students with special learning requirements, but in the spirit of inclusive teaching I think it’s good that all students can access such material. Some faculty are apparently a little nervous that having recordings of lectures available online would result in falling attendances at lectures, but in fact there is evidence that indicates precisely the opposite effect. Students find the recorded version adds quite a lot of value to the “live” event by allowing them to clarify things they might not have not noted down clearly. In my experience they rarely watch the whole video, instead focusing on things they didn’t get first time around. And if a few students decide that it’s good enough for them just to watch the video, then so what? That’s their choice. They are adults, after all.

I’ll add that I do feel we should still make the effort to return to doing live lectures in some form and not rely entirely on recordings. I think that what you can do in a lecture is fairly limited part of the overall educational package, but that’s not the same as saying that they should be scrapped. Many students do enjoy lectures and find them very helpful. I just think we should make the best of the available technology to offer as wide a range of teaching methods as possible. No two students are the same and no two students learn precisely the same way. Let us offer them a variety of resources and they can choose which serves them best.

Another important, but perhaps less tangible, aspect of this is that I think education is or should be a shared experience for students. Just having everyone sit in the same room “enjoying” the same teaching session is a great benefit compared with having them sit in their room watching things on a laptop screen. I think that’s one of the worst issues with remote teaching, and wish we had found better ways of dealing with that over the past year.

There is a benefit for the lecturer of having a live audience too, in that actually seeing the people you’re trying to teach helps you gauge how well you’re getting it across.

Anyway, I started a poll on lecture capture a while ago before the pandemic. Feel free to add your opinion. It will be interesting to see if opinions have changed!

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Remote Exam Time

It’s the day before the start of the January examination period at  Maynooth University so I thought I’d do a quick post on the topic of examinations or, as they are right now, online timed assessments.

First, for readers elsewhere, full-time undergraduate students at Maynooth what is called 60 “credits” in a year, usually split into two semesters of thirty credits each. This is usually split into 5-credit modules with an examination in each module at the end of each semester. Projects, and other continuously-assessed work do not involve a written examination, but the system means that a typical student will have at least 5 written examination papers in January and at least another 5 in May.  This is very similar to the system in most UK universities that I am aware of except that a full year’s work over there is 120 credits so there’s a conversion factor of 2:1. A 5-credit module in Ireland would be a 10-credit module in the United Kingdom, for example, but otherwise the system is similar.

Each examination is usually of two hours’ duration. We’ve kept that length after moving examinations online, although students are given extra time to scan and upload their answers. The question papers themselves have been slightly adapted online use by having much less “bookwork”. Generally these asssessments are unsupervised and students are allowed to consult notes and textbooks so there is little point in asking them to copy out standard derivations and formulae. That means we can concentrate on the problem-solving aspects of theoretical physics, which are the most interesting bits (and perhaps the most challenging).

One big difference between our examinations in Theoretical Physics in Maynooth and those at other institutions I’ve taught at in the UK is that most of the papers here offer no choice of questions to be answered.  A typical format for a two-hour paper is that there are two long questions, each of which counts for 50 marks. Elsewhere  one normally finds students have a choice of two or three questions from four or five on the paper.

One  advantage of our system is that it makes it much harder for students to question-spot in the hope that they can get a good grade by only revising a fraction of the syllabus. If they’re well designed, two long questions can cover quite a lot of the syllabus for a module, which they have to in order to test all the learning outcomes. To accomplish this, questions can be split into parts that may be linked to each other to a greater or lesser extent to explore the connections between different ideas, but also sufficiently separate that a student who can’t do one part can still have a go at others. With such a paper, however, it is a  dangerous strategy for a student to focus only on selected parts of the material in order to pass.

As an examiner, the Maynooth style of examination also has the advantage that you don’t have to worry too much if one question turns out to be harder than the others. That can matter if different students attempt different questions, but not if everyone has to do everything.

But it’s not just the number of questions that’s important, it’s the duration. I’ve never felt that it was even remotely sensible for undergraduate physics examinations to be a speed test, which was often the case when I was a student. Why the need for time pressure? It’s better to be correct than to be fast, I think. I always try to set examination questions that could be done inside two hours by a student who knew the material, including plenty of time for checking so that even a student who made a mistake would have time to correct it and get the right answer. If a student does poorly in this style of examination it will be because they haven’t prepared well enough rather than because they weren’t fast enough.

The structure of the Maynooth examinations at more introductory level is rather different, with some choice. In my first year module on Mechanics & Special Relativity, for example, there is a compulsory first question worth 50 marks (split into several pieces) and then the students can pick two out of three shorter questions worth 25 marks each. This is a somewhat gentler approach than with the more advanced papers, partly adopted because we have quite a few students doing the General Science degree who taking Mathematical Physics as one of their 4 first-year subjects but will not be taking it further.

As both my examinations are not until next week, I’ll have to wait to find out how my students have done. This will be the examination taken at University level for most of my class, so let me take this opportunity to pass on a few quick tips.

1. Try to get a good night’s sleep before the examination!
2. Be ready well before the start and try to ensure you won’t be disturbed for the duration.
3. If you’re doing an unsupervised examination
4. Read the entire paper before starting to answer any questions. In particular, make sure you are aware of any supplementary information, formulae, etc, given in the rubric or at the end.
5. Start off by tackling the question you are most confident about answering, even if it’s not Question 1. This will help settle any nerves.
6. Don’t rush! Students often lose marks by making careless errors. Check all your numerical results on your calculator at least twice and – PLEASE – remember to put the units!
7. Don’t panic! You’re not expected to answer everything perfectly. A first-class mark is anything over 70%, so don’t worry if there are bits you can’t do. If you get stuck on a part of a question, don’t waste too much time on it (especially if it’s just a few marks). Just leave it and move on. You can always come back to it later.

Oh, and good luck to anyone at Maynooth or elsewhere taking examinations in the next few weeks!

P.S. It snowed overnight in Maynooth, although only a centimetre or so…

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Temporary Lectureship in Theoretical Physics at Maynooth University!

While I remember I should announce that we have fixed term ten-month full-time teaching position available in the Department of Theoretical Physics at Maynooth University.

The appointment is to provide sabbatical cover for Dr Jiri Vala.

The advert only went up last week but the deadline is just a fortnight away, on Sunday 12th July, which is pretty soon. This is because we need the person in post by September! Interviews are likely to be held in early August.

You can find the ad here or here or at the Maynooth University website here (which is also where you should apply).

Please feel free to pass this on to anyone you think might be interested!

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