If Oscar Wilde were a Torus
Posted in mathematics with tags genus, Oscar Wilde, quotations, Topology, torus on March 3, 2025 by telescoperTerm goes on…
Posted in Biographical, Education, Maynooth with tags John and Pat Hume Scholarships, Maynooth University, PhD students, research, research students, teaching on March 2, 2025 by telescoperHere we are, about to start the fifth week of the Spring semester at Maynooth University. Teaching isn’t going too badly, but I have come to realize that I have a lot of continuous assessment marking to do – classs tests and mini-projects for Computational Physics and assignments for Particle Physics. The numbers of students involved are 32 in the first case and 23 in the second, but I have to do all the corrections myself. Ho hum. Still, I’m enjoying teaching particle physics again after a gap of 15 years or so so I can’t complain about that.
Last week saw some important achievements by research students. Two students in the Department of Physics – one of them supervised by me – submitted their PhD theses last week. Nominations of examiners have to be approved by Faculty and Academic Council but that should be a formality and we then have the viva voce examinations, so the process is not over yet, but the submission of a thesis is a landmark in itself and is to be celebrated.
Something less worthy of celebration is the ongoing chaos at Maynooth over funding for future research students. You may recall that I posted about the terrible decision by the Management of Maynooth University to scrap the John and Pat Hume Doctoral Scholarships and followed this up with another post suggesting the decision might be reversed and another pointing out that it hadn’t been. The Hume scheme has been paused for a “review”. That review was actually completed in January. It is now March and academic staff have still had no word about the status of the Hume Scholarships. Someone is stalling.
I have received a number of enquiries in recent weeks from prospective students about when applications would open as I’m sure is also the case for several of my colleagues. It has been very depressing to have to reply saying that I have no idea. As far as I know the scheme is suspended indefinitely. It’s now effectively too late for this year anyway, as most prospective students will already have lined up offers elsewhere. Only students not able to secure a place elsewhere will be available to apply if and when the scheme does open.
The timing of this is especially sad for the new Department of Physics. Our final-year Theoretical Physics class sizes are larger than ever but the Maynooth is sending them a very clear signal that it doesn’t want any of them to stay here for their PhDs.
A Poem for St David’s Day
Posted in Poetry with tags Dylan Thomas, Poem, Poetry, St David's Day, The hand that signed the paper on March 1, 2025 by telescoper
It’s St David’s Day so, notwithstanding the fact that I’ve just watched Leinster beat Cardiff 42-24 at Rugby,
Dydd Gŵyl Dewi Hapus!
On this day I usually post a poem by a Welsh poet. This, by Dylan Thomas, which was published in 1936 and seems to me to be rather topical, featured in the concert I went to about a month ago.
The hand that signed the paper felled a city;
Five sovereign fingers taxed the breath,
Doubled the globe of dead and halved a country;
These five kings did a king to death.
The mighty hand leads to a sloping shoulder,
The finger joints are cramped with chalk;
A goose's quill has put an end to murder
That put an end to talk.
The hand that signed the treaty bred a fever,
And famine grew, and locusts came;
Great is the hand that holds dominion over
Man by a scribbled name.
The five kings count the dead but do not soften
The crusted wound nor pat the brow;
A hand rules pity as a hand rules heaven;
Hands have no tears to flow.
Weekly Update from the Open Journal of Astrophysics – 01/03/2025
Posted in OJAp Papers, Open Access, The Universe and Stuff with tags arXiv:2401.16608v3, arXiv:2410.18191v2, arXiv:2411.06594v2, Astrid Simulations, Astrophysics of Galaxies, Baryonic Feedback, cosmological parameters, Cosmology, Cosmology and NonGalactic Astrophysics, Diamond Open Access, Diamond Open Access Publishing, JWST Galaxies, Open Access Publishing, The Open Journal of Astrophysics, Turbulence on March 1, 2025 by telescoperIt’s time once more for the regular Saturday morning update of papers published at the Open Journal of Astrophysics. Things have picked up a bit after a quiet couple of weeks. Since the last update we have published three new papers which brings the number in Volume 8 (2025) up to 21 and the total so far published by OJAp up to 256. We’re now officially a byte-sized journal!
In chronological order of publication, the three papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.
The first paper to report is “Baryon-free S_8 tension with stage IV cosmic shear surveys” by Ottavia Truttero, Joe Zuntz, Alkistis Pourtsidou and Naomi Robertson (all based at the University of Edinburgh, UK). This paper is in the folder marked Cosmology and NonGalactic Astrophysics and it was published on Monday 24th February 2025. It presents a study of the effect of baryonic feedback in the determination of cosmological parameters and the possibility of using large-scale clustering information to mitigate its effects
Here is the overlay:
You can read the officially accepted version of this paper on arXiv here.
The second paper of the week is “Power Spectra of JWST images of Local Galaxies: Searching for Disk Thickness” by Bruce Elmegreen (USA) and 15 others based in the USA, Sweden, UK, Italy and Australia.
It appears in the folder Astrophysics of Galaxies and it describes a method for Looking for a ‘kink’ in the power spectrum of galaxy images that might indicate at some transition from two-dimensional to three-dimensional turbulence on the scale of the disk thickness. This paper was published on Wednesday 26th February 2025.
Here is the overlay:
You can find the officially accepted version of this paper on arXiv here.
The final paper, also published on Wednesday 26th February in the folder Astrophysics of Galaxies is “The evolution of galaxy morphology from redshift z=6 to 3: Mock JWST observations of galaxies in the ASTRID simulation” by Patrick LaChance (Carnegie Mellon University, Pittsburgh; hereafter CMU), Rupert Croft (CMU), Yueying Ni (CfA Harvard), Nianyi Chen (CMU), Tiziana Di Matteo (CMU), and Simeon Bird (UC Riverside); all based in the USA. This paper describes an An analysis of a large sample of mock observations of JWST galaxies obtained from the ASTRID simulation revealing how galaxy properties are expected to evolve with redshift.
Here is the overlay:
The official published version can be found on the arXiv here.
That brings us up to the end of February 2025. I had a delve through the archives and found that by the same stage last year we published 17 papers compared to this year’s 21. It’s small numbers, of course, but we’re up about 23% so far this year.
That’s all for this week. I’ll do another update next Saturday.
The Universe Keeper
Posted in Maynooth, The Universe and Stuff with tags Albert Einstein, Kay Lehnert, Physics, Renata Kallosh, String Theory, Swampland, Wolfgang Pauli on February 28, 2025 by telescoperInterested in learning a little bit about the ideas behind string theory? Here’s a short video that tries to explain the basics in a thought-provoking way. It features three main characters: The Universe Keeper Renata, inspired by Russian-American physicist Renata Kallosh, the quizzical Wolfie, inspired by the Austrian Nobel laureate Wolfgang Pauli, and the inquisitive Albie, inspired by Albert Einstein.
See what you make of it…
(One of the creators of this video is my PhD student Kay Lehnert, who has just given a departmental seminar in which he mentioned the video.)
Roger Penrose: Discoverer of Black Holes?
Posted in History, The Universe and Stuff with tags black holes, John Michell, Karl Schwarzschild, Laplace, Louise Webster, Paul Murdin, Pierre-Simon Laplace, Roger Penrose, Roy Kerr, Times Literary Supplement on February 27, 2025 by telescoperI got home from a busy day on campus to find the 21st February issue of the Times Literary Supplement had landed on my doormat having arrived today, 27th February. It used to take a couple of weeks for my subscription copy to reach Ireland but recently the service has improved. Intriguingly, the envelope it comes in is postmarked Bratislava…
But I digress. This is the cover:
The text below the title “Light on darkness” under the graphic reads “Roger Penrose, discoverer of black holes, by Jennan Ismael”. Nice though it is to see science featured in the Times Literary Supplement for a change and much as I admire Roger Penrose, it is unreasonable to describe him as “the discoverer of black holes”.
A black hole represents a region of space-time where the action of gravity is sufficiently strong that light cannot escape. The idea that such a phenomenon might exist dates back to John Michell, an English clergyman, in 1783, and later by Pierre-Simon Laplace but black holes are most commonly associated with Einstein’s theory of general relativity. Indeed, one of the first exact solutions of Einstein’s equations to be found describes such an object. The famous Schwarzschild solution was obtained in 1915 by Karl Schwarzschild, who died soon after on the Eastern front in the First World War. The solution corresponds to a spherically-symmetric distribution of matter, and it was originally intended that it could form the basis of a mathematical model for a star. It was soon realised, however that for an object of any mass M there is a critical radius (Rs, the Schwarzschild radius) such that if all the mass is squashed inside Rs then no light can escape. In terms of the mass M, velocity of light c, and Newton’s constant G, the critical radius is given by Rs = 2GM/c2 . For the mass of the Earth, the critical radius is only 1cm, whereas for the Sun it is about 3km.
Since the pioneering work of Schwarzschild, research on black holes has been intense and other kinds of mathematical solutions have been obtained. For example, the Kerr solution describes a rotating black hole and the Reissner -Nordstrom solution corresponds to a black hole with an electric charge. Various theorems have also been demonstrated relating to the so-called `no-hair’ conjecture: that black holes give very little outward sign of what is inside.
Some people felt that the Schwarzschild solution was physically unrealistic as it required a completely spherical object, but Roger Penrose showed mathematically that the existence of a trapped surface was a generic consequence of gravitational collapse, the result that won him the Nobel Prize in 2020. His work did much to convince scientists of the physical reality of black holes, and he deserved his Nobel Prize, but I don’t think it is fair to say he “discovered” them.
I would say that, as is the case for discoveries in many branches of science, there isn’t just one “discoverer” of black holes: there were important contributions by many people along the way.
P.S. If you want to limit the application of the word “discovery” to observations then I think that the discovery of black holes is down to Paul Murdin and Louise Webster who identified the first really plausible candidate for a black hole in Cygnus X-1, way back in 1971…
P.P.S. The term “Black Hole” was, as far as I know, coined by John Wheeler in 1967.
Roger Penrose is 93.
The University of Edinburgh in Crisis
Posted in Education, Finance with tags Higher Education, The University of Edinburgh, UCU, University and Colleges Union, university funding on February 26, 2025 by telescoperIt seems that financial emergencies are spreading around the United Kingdom like a contagion. About a month ago I posted about the crisis at Cardiff University, but now there’s a bombshell about the University of Edinburgh which, according to the Times Higher is planning to make cuts of around £140 million in recurrent expenditure, about 10% of its annual operating budget. This level of cuts is greater than those previously listed at other universities, including Cardiff, the largest of which are measured in tens of millions. The piece goes on to explain that target can’t be reached by voluntary redundancies, which presumably means compulsory redundancies are looming.
I don’t know which particular academic units are under threat, but I’m sure this episode is causing a great deal of stress to a great many people. The only advice I can offer to anyone at Edinburgh worrying about the future is, if they haven’t done so already, to JOIN A UNION!
Talking of which, the University of Edinburgh UCU has pointed out that the University revealed a budget surplus last year and has huge reserves measured in the billions. It accuses managers of manufacturing a crisis in order to cut staff and bring about even more centralisation – thus achieving an even greater level of corporate control over teaching and research activities. The subordination of academia to management is the aim. I don’t doubt that university managers around the world believe that teaching will be largely done by AI anyway which will allow even more lecturing staff to be cut.
I believe that universities need less centralisation not more. The Principal of the University of Edinburgh, Peter Mathieson, is quoted in the Times Higher piece as saying:
We can no longer afford to run duplicative services across the university, often with inconsistent practices which create inefficiencies, increase staff workload and impact our student experience..
This is fair enough, but it is quite wrong to assume that greater centralisation is the solution. In my experience it is “The Centre” that creates inefficiencies, increases staff workload and impacts student experience. That is because it knows far less than Schools and Departments about what is needed to achieve their academic objectives. Universities need a flatter and more responsive structure, not the ever-increasing management bloat that has been imposed on them for decades and which is now causing them to capsize.
Beautiful Equations
Posted in Biographical, mathematics, The Universe and Stuff with tags Beauty, Dirac equation, mathematics, Particle Physics, Paul Dirac on February 25, 2025 by telescoperI did a lecture today about the Dirac Equation (which is almost 100 years old, having been first presented in 1928). You might think this is a difficult topic to lecture on, but it’s really a piece of cake:
This reminds me that a a while ago I posted about an interesting article on the BBC website that discussed the way mathematicians’ brains appear to perceive “beauty”. A (slightly) more technical version of the story can be found here. According to functional magnetic resonance imaging studies, it seems that beautiful equations excite the same sort of brain activity as beautiful music or art.
The question of why we think equations are beautiful is one that has come up a number of times on this blog. I suspect the answer is a slightly different one for theoretical physicists compared with pure mathematicians. Anyway, I thought it might be fun to invite people offer suggestions through the comments box as to the most beautiful equation along with a brief description of why.
I should set the ball rolling myself, and I will do so with the Dirac Equation:
This equation is certainly the most beautiful thing I’ve ever come across in theoretical physics, though I don’t find it easy to articulate precisely why. I think it’s partly because it is such a wonderfully compact fusion of two historic achievements in physics – special relativity and quantum mechanics – but also partly because of the great leaps of the imagination that were needed along the journey to derive it and my consequent admiration for the intellectual struggle involved. I feel it is therefore as much an emotional response to the achievement of another human being – such as one feels when hearing great music or looking at great art – as it is a rational response to the mathematical structure involved. But it’s not just that, of course. The Dirac Equation paved the way to many further developments in particle physics. It seems to encapsulate so much about the behaviour of elementary particles in so few symbols. Some of its beauty derives from its compactness- it uses up less chalk in a mathematical physics lecture.
Anyway, feel free to suggest formulae or equations, preferably with a brief explanation of why you think they’re so beautiful.
P.S. Paul Dirac was my (academic) great-grandfather.
R.I.P Roberta Flack (1937-2025)
Posted in Music, R.I.P. with tags Roberta Flack, The First Time Ever I Saw Your Face on February 24, 2025 by telescoperI just heard the sad news of the death at the age of 88 of the wonderful singer Roberta Flack. Many years ago I posted my favourite song of hers (performed live on Top of the Pops way back in 1972) but it seems the link I used is now broken so I’ll post the original version. Roberta Flack’s The First Time Ever I Saw Your Face first appeared on her album First Take back in 1969 but it didn’t become a hit until it featured in Clint Eastwood’s (1971) film Play Misty For Me. Incidentally, the bass player on this track is the great Ron Carter.
It’s probably the most beautiful love song I’ve ever heard and to my mind it hasn’t dated at all in 50 years. I suppose if you’ve ever felt about someone the way it describes you never forget…
Rest in peace, Roberta Flack (1937-2025). To the dark, and the endless skies.
Particle Physics Masterclass at Maynooth
Posted in Education, Maynooth, The Universe and Stuff with tags Maynooth University, Particle Physics, Particle Physics Masterclass on February 23, 2025 by telescoper
Last week’s announcement about Ireland joining CERN reminded me that I should have advertised the annual Particle Physics Masterclass at Maynooth University long before now, not least because I’m actually teaching particle physics this year. My only excuse is that I’m old and forgetful. Anyway, better late than never; there’s still almost a week until the registration closes.
Since 2012 the Department of Theoretical Physics hosted the International Particle Physics Masterclasses for secondary school students each spring (except for 2020 when it was cancelled due to Covid-19 restrictions). Now the Department of Theoretical Physics is no more, having been incorporated last year into the Department of Physics, but the Particle Physics Masterclasses continue; the next event will be on Tuesday 18 March 2025.
These Masterclasses give secondary school students the opportunity to discover the world of quarks and leptons for themselves, by performing measurements on real data from CERN, meeting active particle physics researchers and linking up with like-minded students from other countries. We will join thousands of other secondary school students at more than 100 universities and laboratories around Europe and worldwide in a programme stretching over four weeks.
Physics at the most fundamental level – the smallest and most basic building blocks of matter – is an exotic world. But a few introductory talks and working with data from CERN will give the students insight into the fundamental particles of matter and the forces between them, as well as what went on during the Big Bang.
In the morning the students are introduced to particle physics, experiments and detectors in lectures given by active particle physics researchers. After an early lunch, they work on their own with data from the ALICE detector at CERN. Afterwards they participate in a video conference with students from other countries and moderators at CERN, where they discuss and compare their results. For more information on the masterclasses, see the International Masterclasses web site.
You can find more information about the event here and you can register here. Hurry up though as the deadline for registration is the end of this month, i.e. this Friday, February 28th!
In the Dark 