Machine Learning in the Physical Sciences

Posted in The Universe and Stuff with tags , , , , , on March 29, 2019 by telescoper

If, like me, you feel a bit left behind by goings-on in the field of Machine Learning and how it impacts on physics then there’s now a very comprehensive review by Carleo et al on the arXiv.

Here is a picture from the paper, which I have included so that this post has a picture in it:

The abstract reads:

Machine learning encompasses a broad range of algorithms and modeling tools used for a vast array of data processing tasks, which has entered most scientific disciplines in recent years. We review in a selective way the recent research on the interface between machine learning and physical sciences.This includes conceptual developments in machine learning (ML) motivated by physical insights, applications of machine learning techniques to several domains in physics, and cross-fertilization between the two fields. After giving basic notion of machine learning methods and principles, we describe examples of how statistical physics is used to understand methods in ML. We then move to describe applications of ML methods in particle physics and cosmology, quantum many body physics, quantum computing, and chemical and material physics. We also highlight research and development into novel computing architectures aimed at accelerating ML. In each of the sections we describe recent successes as well as domain-specific methodology and challenges.

The next step after Machine Learning will of course be Machine Teaching…

BICEP2: Is the Signal Cosmological?

Posted in Astrohype, The Universe and Stuff with tags , , on March 28, 2019 by telescoper

An article in Physics Today just reminded me just now that I have missed the fifth anniversary of the BICEP2 announcement of `the detection of primordial gravitational waves’. I know I’m a week but I thought I’d reblog the post I wrote on March 19th 2014.You will see that I was sceptical…

..and it subsequently turned out that I was right to be so.

telescoper's avatarIn the Dark

I have a short gap in my schedule today so I thought I would use it to post a short note about the BICEP2 results announced to great excitement on Monday.

There has been a great deal of coverage in the popular media about a “Spectacular Cosmic Discovery” and this is mirrored by excitement at a more technical level about the theoretical implications of the BICEP2 results. Having taken a bit of time out last night to go through the discovery paper, I think I should say that I think all this excitement is very premature. In that respect I agree with the result of my straw poll.

First of all let me make it clear that the BICEP2 experiment is absolutely superb. It was designed and built by top-class scientists and has clearly functioned brilliantly to improve its sensitivity so much that it has gone so…

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Brexit: What’s the Indicative Mood?

Posted in Pedantry, Politics with tags , , , , , on March 27, 2019 by telescoper

If you are confused about today’s `Indicative Votes’ in Parliament on Brexit let me provide some helpful information about the indicative mood, and how it relates to Brexit.

The English word “exit” is derived from the third person singular of the present tense in the indicative mood in the active voice of the Latin verb “exire” (“to go out”) i.e. it means “he/she/it leaves”, though the noun form it usually has in English derives from the supine form “exitus”. I feel it is important that we all get used to the grammar of Brexit, so here is a fairly complete list of the parts of the verb `Brexire’ in the active voice of the indicative mood, some or all of which may be relevant in the forthcoming debates, complete with accents to assist punctuation. At least these may prove useful in following any contributions from Jacob Rees-Mogg.

First let’s start with the basics:

Infinitive: Brexīre
Present participle: Brexiēns; Brexiéntis
Future participle: Brexītúrus
Gerund: Brexeúndum
Gerundive: Brexeúndus

And now here are representative examples of the conjugation of the verb Brexire in various tenses of the Indicative Mood in the order: first, second and third person singular followed by first, second and third person plural:

Present:

Brexeō,
Brexīs
Brexit
Brexīmus
Brexītis
Brexeunt

Past Imperfect

Brexībam
Brexībās
Brexībat
Brexībāmus
Brexībātis
Brexībant

Past Perfect

Brexiī
Brexīstī
Brexiit
Brexíimus
Brexīstis
Brexiḗrunt

Pluperfect

Brexíeram
Brexierās
Brexíerat
Brexierāmus
Brexierātis
Brexierant

Future Simple

Brexībō
Brexībis
Brexībit
Brexībimus
Brexībitis
Brexībunt

Future Perfect

Brexíerō
Brexíeris
Brexíerit
Brexiérimus
Brexieritis
Brexierint

The last tense here is not really relevant, but I’ve included it anyway.

No doubt when the Indicative votes are over, the House of Commons will proceed to the Subjunctive Mood – or even directly to the Imperative – but I shall leave these to a future post.

Changing Time

Posted in History, Politics with tags , , , , , , , , , on March 27, 2019 by telescoper

Among the many sensible decisions made yesterday by the European Parliament was to approve a directive that will abolish `Daylight Saving Time’. I’ve long felt that the annual ritual of putting the clocks forward in the Spring and back again in the Autumn was a waste of time effort, so I’ll be glad when this silly practice is terminated.
It would be better in my view to stick with a single Mean Time throughout the year. I’m only disappointed that this won’t happen until 2021 as EU countries have to enact the necessary legislation according to their constitutional processes.

The marvellous poster above is from 1916, when British Summer Time was introduced. I was surprised to learn recently that the practice of changing clocks backwards and forwards is only about a hundred years old. in the United Kingdom. To be honest I’m also surprised that the practice persists to this day, as I can’t see any real advantage in it. Any institution or organisation that really wants to change its working hours in summer can easily do so, but the world of work is far more flexible nowadays than it was a hundred years ago and I think few would feel the need.

Anyway, while I am on about Mean Time, here is a another poster from 1916.

Until October 1916, clocks in Ireland were set to Dublin Mean Time, as defined at Dunsink Observatory rather than at Greenwich. The adoption of GMT in Ireland was driven largely by the fact that the British authorities found that the time difference between Dublin and London had confused telegraphic communications during the Easter Rising earlier in 1916. Its imposition was therefore, at least in part, intended to bring Ireland under closer control and this did not go down well with Irish nationalists.

Ireland had not moved to Summer Time with Britain in May 1916 because of the Easter Rising. Dublin Mean Time was 25 minutes 21 seconds behind GMT but the change was introduced at the same time as BST ended in the UK, hence the alteration by one hour minus 25 minutes 21 seconds, ie 34 minutes and 39 seconds as in the poster.

Britain will probably not scrap British Summer Time immediately as it will be out of the European Union by then. British xenophobia will resist this change on the grounds that anything to do with the EU must be bad. What happens to Northern Ireland when Ireland scraps Daylight Saving Time is yet to be seen.

Moreover the desire expressed by more than one Brexiter to return to the 18th Century may be behind the postponement of the Brexit deadline from 29th March to 12th April may be the result of an attempt to repeal the new-fangled Gregorian calendar (introduced in continental Europe in 1582 but not adopted by Britain until 1750). It’s not quite right though: 29th March in the Gregorian calendar would be 11th April in the Gregorian calendar…

I’ve no more … to give

Posted in Biographical, Music, Politics with tags , on March 26, 2019 by telescoper

And now here’s a vocal summation of my views on Brexit by Thomas Benjamin Wild Esq, a chap with a lovely beard…

Feline Film Star

Posted in Maynooth with tags on March 26, 2019 by telescoper

As I was walking into work this morning I noticed that the local celebrity cat was preparing for a location shoot for a film he’s going to be starring in.

I’m not at liberty to give any more details about the film, but I’m not surprised he’s been offered a central part as he is a natural in front of the camera. In my experience cats are generally difficult subjects, as they have a tendency to wander off or otherwise get distracted as soon as you try to photograph them. This one is quite happy to pose. I’ll post an update when the movie is released.

How big was the 23rd March Put It To The Vote march? A: too big to ignore

Posted in Uncategorized with tags , , , , on March 25, 2019 by telescoper

This post offers some interesting reflections on Saturday’s march. I recall the anti-War march in 2003 and would say that Saturday’s was similar in size, and both were substantially larger than the one last autumn.

I heard the organisers announce an official estimate of 1 million (without an error bar). Not being able to reach the end of the march – barely got halfway – I can’t make a quantitative estimate. I’ll just say that if someone told me it was two or three times as big as the one in 2018 then I wouldn’t be surprised.

I’ll just add that it was very enjoyable and the participants were very friendly and polite – so different from the abusive and threatening conduct of the other side. That is probably the Remainers’ biggest problem – we’re just too nice. The government is far more likely to be swayed by threats of `blood on the streets’ than civilized peaceful protest, which is why I fear so much for the direction in which the UK is heading.

kmflett's avatarKmflett's Blog

How big was the 23rd March Put It To The Vote march? A: too big to ignore

I was not able due to other commitments to pay more than passing direct attention to the People’s Vote in central London on 23rd March.

As might be expected I’m no fan of the named organisers but that is hardly the point. A very large demonstration brings all sorts of people and ideas onto the streets and opens up possibilities.

The organisers pre-claimed the march would be a million strong and repeated that afterwards as well. To be fair with such a large march over a relatively short distance ending up in a restricted space its very difficult to tell. My general views on the size of protests are here:

https://kmflett.wordpress.com/2019/03/21/once-gain-on-the-size-of-protests-the-peoples-vote-march-23rd-march/

There were some slightly odd claims. One twitter post showed the Mall full for a Royal event in a previous…

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Fine-tuning in Cosmology

Posted in The Universe and Stuff with tags , , , , , on March 25, 2019 by telescoper

I forgot to post a link to a paper by Fred Adams that appeared on the arXiv last month on the topic of the fine-tuning of the Universe which I had bookmarked for a blog a while ago.

My heart always sinks when the arXiv informs me that the abstract of a paper is `abridged’ so here’s the full version from the PDF you can download for yourself here. Please be aware, though, that it’s a lengthy paper running to over two hundred pages:

My own view on this topic is that it is indeed remarkable that the Universe is finely-tuned to exactly the extent required to allow authors to write such long papers about the fine-tuning of the Universe…

 

Promoting the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , on March 24, 2019 by telescoper

The talk I gave at the meeting I attended last week to celebrate the retirement 60th Birthday of Alan Heavens was about the Open Journal of Astrophysics project. Here are the slides:

I decided a while ago that whenever I get the opportunity at conferences or other meetings I will talk about the Open Journal of Astrophysics (OJA for short) , mainly to encourage more submissions but also to raise OJA’s profile so people aren’t tempted to dismiss review invitations as spam from predatory journals.  At the moment, refereeing is the rate-limiting step in the publication process, at least part of the reason being that people don’t really know what we’re about and perhaps assume that it’s not a bona fide operation.

The talk I gave on Friday generated a fair amount of discussion, and was hopefully a small step along the way to establishing OJA as a mainstream journal and perhaps even the default choice for papers on astrophysics. Emma Chapman posted a tweet about my talk (including a picture of me in action) which got quite a lot of attention on Twitter:

 

https://twitter.com/DrEOChapman/status/1109125125411139584

I’ll just add that you can read more about the extent of the profiteering going on here.

 

Finally, and perhaps most importantly, let me mention I have some money (in a grant courtesy of the Gordon & Betty Moore Foundation) to help promote this project, and I can legitimately spend it on travel to give talks etc.. If anyone would like a talk about this project, please feel free to contact me!

 

A Very British March

Posted in Biographical, Politics with tags , , , , on March 24, 2019 by telescoper

I’m back in Maynooth now after yesterday’s wonderful demonstration in London. Sources are claiming that about 1.4M people attended. I met filk from all round the country, many of whom had never been on a march before. It’s also worth saying according to the Metropolitan Police that there was not a single incident that they had to deal with.

I’m not very good in big crowds (to say the least) so I stood for a while a little distance from the main body of the demonstration as it assembled in Park Lane. I was astonished to see how many people were joining. It was certainly larger than the previous one, last year.

I eventually joined in when it started moving (very slowly). The people were very friendly and despite the numbers I didn’t get at all panicky. It struck me as being a quintessentially British demonstration, in that it was basically just some very nice polite people waiting politely in a very long queue..

The march was due to start at 12 noon but i didn’t get going until well after 2pm. I had to leave at 4pm, by which I had only got halfway along Piccadilly. Instead of going all the way to Parliament Square I headed back to my hotel, picked up the bag I had left there and took a packed tube to Heathrow. I made it just in time. The plane began boarding just as I ckeated the security checks.

I didn’t take many pictures of the march, but here are a few:

Hyde Park, the Statue of Achilles

Philosopher A. C. Grayling and I..

Beards against Brexit!

It was a wonderful experience to be in the company of so many extremely nice people and I was sad I couldn’t make it all the way to the end!

P. S. The petition on revoking Article 50 has reached almost reached 5 million signatures.