Friday, 20 December 2013

Roguelike of the Year

Over at Ascii Dreams, there's the annual vote for Roguelike of the Year.  The correct vote, of course, is for Sil, though it looks like ToME 4 will win again.  I do still plan to get around to talking about ToME, but it's clear I'm not as fond of the game as most people.

Wednesday, 9 October 2013

Physics Nobel to Higgs & Englert

Congratulations are due to Peter Higgs and Francois Englert, winning the Nobel prize this year for their work on the mechanism on spontaneous symmetry breaking.  The work was done way back in the '60s, but of course it was essentially confirmed by the discovery at the LHC last year of a new particle with the predicted properties.  Like all discoveries, a number of people contributed, but Higgs in particular predicted the existence of a new bosonic particle.  Based on the press release, it looks like Robert Brout might also have won had he still been alive.

Saturday, 28 September 2013

Line of the Week

Phil Plait, writer of the Bad Astronomy blog, is one of the greats of the skeptical blogosphere.  But I must confess, I don't tend to read him on a regular basis; nothing against him, it's just a personal choice based on limited time.  So I wasn't aware of just how awesome he is at dealing with the climate change denialist industry.  Earlier this month, there was this wonderful piece dealing with an article from the Mail on Sunday (which I noted because parts of the original article was read to me by relatives I was visiting at the time).

Then this week we've had this summary piece, and finally the article that prompted this post: a rebuttal to an article in the Daily Telegraph.  Which brings the following: (initial quote is from the Telegraph article)
This is why the latest Assessment Report is proving such a headache to the IPCC. It’s the first in its history to admit what its critics have said for years: global warming did “pause” unexpectedly in 1998 and shows no sign of resuming. And, other than an ad hoc new theory about the missing heat having been absorbed by the deep ocean, it cannot come up with a convincing explanation why. 
 Well, actually, no. That’s like seeing a corpse with a bullet wound to the head and saying “Except for the bullet wound to the head you cannot come up with a convincing explanation why this person is dead.”
I applaud you, sir.

Wednesday, 25 September 2013

Fucking Hell

At this point, I think Tony Abbot's party is full of stereotypical movie villains twirling their mustaches.
The Coalition is considering reintroducing a cap on university places despite emphatically ruling it out last year while in opposition.
The minister for education, Christopher Pyne, has confirmed he is considering reintroducing the cap on university places as well as abolishing the compulsory fee paid by students to fund campus services and scrapping the targets that were introduced by Labor to allow more disadvantaged students to enter university.
Anti-education: check.  Anti-poor: check.  Add the anti-science policies I've already discussed, and it reminds me of the line from Pratchett: the only thing that depressed him more than his own cynicism, was that sometimes he wasn't cynical enough.

Climate Body Reopens

Tony Abbot made clear his position after winning the election two and a half years ago by scrapping the position of science minister, funds to stimulate green industries and scrapping the Climate Commission, a body tasked with analysing the science of climate change.  In a small piece of good news, the Commission has reopened:
An Australian climate change body scrapped by the new government has been relaunched as a non-profit organisation reliant on public donations. 
 ...
But the group resurrected itself as the Climate Council, saying it hoped "Obama-style" public donations raised online would keep it open
Australia is the developed world's worst polluter per head of population.

Monday, 23 September 2013

Axion Dark Matter in Tabletop Experiments

A paper from last week offered a very interesting suggestion for a new type of search for axion dark matter, as well as the possibility that it may already have been seen.

I've talked about dark matter a few times on this blog, but I don't think I've yet mentioned axions.  Part of the reason for this is that axions are somewhat outside my area of expertise.  Still, the main points that are needed here are that axions are very light, very weakly interacting particles.  By light, we are talking at least a billion times lighter than the electron.  Like WIMPs, axions are introduced for unrelated reasons yet can serve as natural dark matter candidates.

Friday, 13 September 2013

Prescience

Once again, a news story:
The Voyager-1 spacecraft has become the first manmade object to leave the Solar System.
brings to mind an old XKCD comic (from earlier this year):

Tuesday, 10 September 2013

Election Records

2008, November 4th: US election.  I was in the US, in my primary residence.  Result: Obama wins White House, Democrats take both houses.  The best possible result at that time.

2010, May 6th: UK general election.  I was not in the UK at the time.  Tories win, and proceed to prove how little they care for the poor.

2011, May 2nd: Canadian Federal election.  I was travelling to a conference, and thus missed the actual election date.  Despite having been held in contempt of parliament for lying, conservative government not only is reelected, but with an increased margin of victory.

2013, September 7th: Australian Federal election.  Despite Australia having enjoyed economic growth during the world recession, the government is voted out in place of an anti-science, homophobic conservative.

I need to stop travelling during elections.

Friday, 6 September 2013

Wired, PAX and alternatives

My attention was drawn to an article at Wired on PAX, dickwolves and the related controversy:
Whether or not the strip was offensive in itself isn’t really relevant at this point: More than the comic itself, what made the most impact was how Penny Arcade responded to the readers — including rape survivors — who said it upset them.
I'm not going to say much on this beyond "go read the article", as I don't read Penny Arcade and only heard about all this post facto.  However, I will draw your attention to the links over on the right, several of which are webcomics worthy of reading.  Most particularly, it was Jeph Jacques's Twitter feed that alerted me to the above article.  While Questionable Content is one of the older, best-known webcomics and hardly needs a no-name blogger like myself to raise its profile, it serves as a nice counter-example.  I feel inspired to go buy some merchandise.

The Hedgehog

Back when I was an undergrad, I joined the University Diplomacy Society, originally drawn by the club's motto: Make New Friends, then Stab them in the Back!  I've since fallen out of playing the game, as the negotiating mechanic doesn't really appeal to me and I can get better tactical games elsewhere.  I still remember a lot of stuff from then, including several of the openings.  One famous opening for Austria-Hungary is the Hedgehog, invented by one of the early writers, Richard Sharp.  This features Austria moving its Fleet (that starts in Trieste) to Italian Venice, as a defensive measure against a possible Italian attack.  The move usually fails, which in Diplomacy is called bouncing.

The reason I bring all this up is that it was very much in my mind last Sunday, when I travelled from Trieste to Venice for a day trip.  Obviously, I could hardly pass up visiting Venice, having never gone before.  But the fact that I wouldn't even stay for one night—that I would bounce—made me smile in memory.

Looking back at SUSY 2013

It's been a busy few days, but I want to take the time to look at SUSY 2013 as a whole.  I'll start by saying that I enjoyed it.  The selection of speakers was excellent, even by the standards you'd expect of such a major conference.  I particularly enjoyed some of the more surprising choices in the first couple of days.  The organisation of the conference was generally good, the food enjoyable and even the coffee above average.  (Though we were in Italy, so perhaps that should have been anticipated.)

Saturday, 31 August 2013

SUSY 2013 Live Blog: Final Session

We end with some review and summary talks.

10:30am: John Ellis, "Outlook for supersymmetry"

A clue about John's opinion: his t-shirt has "MSSM" written on it.

I recognise the opening slide from Cairns.

"Is outlook for SUSY black?  Bullshit!"  Claims Higgs observations provide more evidence for SUSY, not less.

The LHC paradox: a light Higgs plus nothing else?  If there is something else light, why haven't we seen it?  If there is nothing light, is the Higgs unnatural?  There has been a high mortality rate among theories, but not SUSY.  Comment on split-/High scale-/etc. SUSY, "If you can't say something good, say nothing".

SUSY anywhere is better than SUSY nowhere.

Mh-Mt close to stability bound.  Instability sets in at 1010-1013 GeV.  Claim that we do need to fix this.  Natural way to do this is to add a new stop-like scalar, but that only brings more fine-tuning and stability issues.  These are best solved with a Higgsino.

"Anybody sensible would say that the Higgs that has been observed is the lightest supersymmetric Higgs."

Various data that has to go into global fits.  Big question is g-2.  Is there low-scale SUSY, as this suggests?

2012 data does not rule out as much of CMSSM parameter space as you might expect.  Even best-fit point of pre-2012 is still fine.  CMSSM has two preferred regions now, one with gluinos just above the exclusion limits and another at 4-5 TeV; latter is probably too heavy for LHC.  Stops have similar masses.  Stau is NLSP, can be as light as several hundred GeV.  Can be long-lived; small mass splitting with LSP (less than tau mass) is preferred in global fits.

Planck evidence: simple SUSY inflationary models fit the constraints, especially no-scale supergravity.

DM DD: Probe SUSY parameter space by 2020.

DM positrons: probably astrophysics, but can use smooth spectra to place constraints.

What's next?  A Higgs factory; LHC upgrades?  ILC?  CLIC?  TLEP?  TLEP could test SUSY predictions in deviations of Higgs couplings.  Most alternatives could not.  TLEP could, like LEP, be later replaced with hadronic collider (100 TeV).

Note: we had to wait 48 years for the Higgs.  We have only been waiting 40 years for SUSY—keep the faith!

11:10 am: Nima Arkani-Hamed, "Supersymmetry 2033"

The title is based on the fact that this is the 21st SUSY conference, so look 20 years back and 20 years forward; plus, of course, the fact the LHC is giving us results and will change things.

The talk is a motivation for a 100 TeV pp machine.  It is an obvious direction.

Precisely what we need to do depends on what is seen at LHC 13/14.  But "every scenario I can envisage will need a 100 TeV machine."  Not obvious it would have been, e.g. had we found light SUSY.

A lot of technically interesting questions, but focus on the physics question.

1. The ultimate fate of naturalness.  Higgs discovery is crucial; our vacuum is qualitatively different to a random condensed matter system.  In none of our studies of EFTs in the lab do we see a light scalar without deliberate external fine-tuning.

Naturalness has been invoked before the Higgs, and every time it worked.  They are: the classical self-energy of the electron, infinite.  Leads to models based on a cut-off; models where wrong, but there was new physics at that scale (QM); in fact, even earlier than it needed to!  (Due to weak EM coupling.)

Second case is the pion; quadratic QED corrections to the pion mass.  Again, quadratically divergent contributions cut-off by the rho, again came in earlier than it needed to.

Third is Kaon mixing.

It may well have worked before, but where is everybody?  This is not a new problem; there has been a tension from the beginning because of the SM approximate symmetries that cannot be broken at the TeV scale.  Not problems, opportunities!

Naturalness has failed dramatically before.  Aristarchos's model of the solar system was unnatural, since the distant stars had to be ridiculously far away!  More recently, we have nuclear physics; consider the small deuteron binding energy, or the fact that two neutrons are not bound by a 1% factor.  Related to up/down quark masses?  And, of course, the cosmological constant problem.

You can use history to argue either way.  Worth keeping that in mind.

The question of if the Higgs scale is natural is then a deep, structural question about the foundation of fundamenal physics.

a. What if LHC sees nothing else.  Tuning of 1% in Higgs mass.  Is that convincing to kill naturalness?  Well, we have seen this kind of tuning before (neutrons!) and has not forced us to make a radical departure in our philosophy.

We can only properly address this question by going to higher energies.  If we find something, we end the discussion.  If we find nothing, we get a quadratic gain in the tuning with the energy of the machine!  So a 100 TeV collider will push the tuning down to 10-4, hundred times worse than anything seen in particle physics before.  Much much harder to dismiss this.

b. Fine-tuned theories could exist that are not anthropically motivated.  Example: find a TeV-scale Higgs, nothing else up to 100 TeV.  Now have worse tuning, and no anthropic reason!  Force us to really reexamine our entire point of view.

c. If we unlucky and NP is just outside of LHC, obviously 100 TeV machine will find it.  Also, consider split scenarios; minimal picture prefers gluino below about 20 TeV, so should be found.  Also, if found and they decay in the detector at all, that tells us new scale not too far away.

d. What if LHC discovers (relatively) natural spectrum?  Will be too heavy to study at a low-energy lepton collider, while coloured particles will not be produced in large numbers of LHC.  Plus, if we do see a natural spectrum then a number of particles will be too heavy to see at the LHC.

2. Robust probe of few TeV electroweak particles, e.g. WIMPs.  Impossible at LHC.

3. Collider flavour physics.  Can not have theory of flavour at 1 TeV, can at 30-40 TeV.  (e.g. RS).  Not guaranteed, by any means, just possible.  Tops produced in large numbers.  Various low-energy probes of CP-violation, EDM etc; if they find anything, the scale must be in the 10s or 100s of TeV.

Summary: "The scientific questions at stake in our field are the deepest ones we have encountered in 50 years."  Our ambition should match the size of the question.  The time to start thinking about this is now.

And with that, SUSY is effectively over.  We have one final talk telling us about SUSY 2014, which will be in Manchester next July.  However, I don't think I need say much about this.

I will write my own thoughts on the conference as a whole some point in the next few days.  First, I'm indulging in a little sightseeing this weekend, and I also need to write a seminar talk by Thursday!

SUSY 2013 Live Blog: Day Six

The final day of SUSY 2013 is, like most conferences, only a half-day.  The two sessions cleanly split into a pre-coffee flavour session, followed by a post-coffee wrap-up.  I'll be honest, the latter is more attractive to me (plus talks from John Ellis and Nima (again)).  But I won't dismiss this first session yet.

Between this being the last day of the conference—so people are starting to leave—and the conference banquet last night, the auditorium is strikingly empty this morning.  Still, unlike some conferences *cough*Pheno 2013*cough* SUSY at least got it right in putting the banquet after all the parallel sessions had finished.

SUSY 2013 Live Blog: Day Five Session Four

So It Has Come To This.  The last parallel session of SUSY 2013.  And what better place to sit than the SUSY Phenomenology session.  We have four talks to bring this part of the conference to a close.

Friday, 30 August 2013

SUSY 2013 Live Blog: Day Five Session Three

We start the last afternoon session of the conference.  I've decided to start out in the Higgs session again.  As I noted last time I was here, this session is heavily subscribed, so we have six fifteen minute talks before the coffee break.  I hope that won't be too much.

SUSY 2013 Live Blog: Day Five Session Two

As usual, we follow the first round of experimental talks with some post-coffee theory.

SUSY 2013 Live Blog: Day Five

We've reached the last ful day of SUSY 2013.  We start the morning with another pair of LHC talks, this times on the so-called exotic searches.  As this is a SUSY conference, they only get 35 minutes, unlike the 45 minutes the SUSY searches got.  Of course, like the SUSY searches we know going in the final statement; nothing has been found.

Montana Judge ...

Do I need to complete that title?  Anyway, a Montana Judge has shown how sexism is dead by handing a one month sentence to a man who raped a 14 year old, saying she was responsible.
A Montana judge who said a 14-year-old rape victim was "as much in control of the situation" as the man who assaulted her is under pressure to resign.
Montana Judge Todd Baugh also said the girl was "older than her chronological age", as he handed the teacher who assaulted her a month in prison.
The mother of the victim, who took her own life three years ago while the case was pending, is furious.
Now if you'll excuse me, I need to go throw up.

SUSY 2013 Live Blog: Day Four, Session Four

Anyone reading this currently will realise I skipped this session.  My own talk was during it, so I wanted to focus on that instead.  I meant to post something to that effect before the session started, but I ended up without time.  My talk went okay, I think, though my throat was very dry by the end of it.

Thursday, 29 August 2013

SUSY 2013 Live Bog: Day Four, Session Three

I've decided to spend the afternoon sessions attending the non-SUSY talks.  Obviously, that's the place to be at a conference called Supersymmetry.

SUSY 2013 Live Blog: Day Four Session Two

The post-coffee break session returns to more very theoretical topics.

SUSY 2013 Live Blog: Day Four

We return to a full day of talks at SUSY.  The morning's plenary sessions open with a talk on dark matter and another on cosmology.

Wednesday, 28 August 2013

SUSY 2013 Day Three

Wednesday is one of two half-days here at SUSY, the other being Saturday.  As such we have only plenary talks this morning, including the two longest talks of the conference.  These are CMS and ATLAS talks on SUSY searches, running to 45 minutes each.

Unfortunately, I won't be able to live blog these as I have some urgent work to take care of.  Still, I can summarise the talks quite simply: nothing has been found despite a lot of clever work, and the limits are getting pretty strong.

SUSY 2013 Live Blog: Day Two Session 4

For the last session of the day I've returned to the SUSY phenomenology parallel talks.

Tuesday, 27 August 2013

SUSY 2013 Live Blog: Day Two Session Three

For the first parallel session of the day I'm in the dark matter/cosmology session.

SUSY 2013 Live Blog: Day Two Session Two

With the first round of experimental talks complete, now we have some theory to discuss the implications.

SUSY 2013 Live Blog: Day Two

The second day of SUSY starts with a pair of experimental talks on the Higgs results.

SUSY 2013 Live Blog: Day 1 Session 4

For the final SUSY 2013 session of the day I'm at the Higgs session.  To noone's surprise, this is by far the most over-subscribed group of sessions.

Monday, 26 August 2013

SUSY 2013 Live Blog: Day 1 Session 3

We progress to the first parallel session of the conference.  I've decided to attend the SUSY phenomenology talks, which in this case appears to actually be SUSY experimental results.  So, four talks saying variations of "we find no signal".  Curiously, we have three CMS talks to only one ATLAS talk.

SUSY 2013 Live Blog: Day 1 Session 2

Two much-needed cups of coffee later, we continue the morning plenary sessions with three talks and no obvious theme that I can see.

SUSY 2013 Live Blog: Day 1

Another conference, and because it went well last time I'm going to continue with live blogging as a proxy for taking notes.  This time it's Supersymmetry 2013, held in Trieste.  Travel here was pretty awful, but I might put my complaints into a different post if I feel like it.  (Protip: don't fly with Alitalia.)

Interestingly, we start with a talk not about LHC results, the Higgs or even SUSY in general.  The first talk after the introduction is Stefano Profumo on Dark Matter.

Thursday, 22 August 2013

Busy Busy Busy

One problem with writing a blog as a scientist is that I spend a good chunk of my time writing other stuff.  In particular, I'm currently writing several talks for SUSY 2013 next week and some seminars in the following weeks.  Much like the problem I have with reading these days, after a hard day's writing I'm not too inclined to spend an hour or more constructing a post here.

Still, I should have the main things finished soon, and I'll likely be live blogging SUSY next week as well.  So that should help me post more regularly again.  Also, as the main game I'll have with me will be ToME, I might finally get around to writing a review of it.

Friday, 16 August 2013

A Christian Talks About Homosexuality

I've often linked to stories with religious people espousing homophobia and other bigotries.  So it's probably time for me to link to something a bit different:
Christians in Britain and the US who claim that they are persecuted should "grow up" and not exaggerate what amounts to feeling "mildly uncomfortable", according to Rowan Williams, who last year stepped down as archbishop of Canterbury after an often turbulent decade.
"When you've had any contact with real persecuted minorities you learn to use the word very chastely," he said. "Persecution is not being made to feel mildly uncomfortable. 'For goodness sake, grow up,' I want to say."
Of course, I have other problems with Williams—even some of the stuff he's quoted as saying within that article—but it's nice to see a cleric call out this type of behaviour.

Airport Security Does Something Useful

This story has me conflicted.
Teenage girls who fear they are being taken abroad to enter into a forced marriage are using a simple trick to escape: hiding a spoon or any other metal object in their underwear to set off the metal detector at the airport and avoid the flight at the last minute.
On the one hand, it's a story of success: these girls are avoiding a nasty fate with a simple but ingenious idea.  On the other, they shouldn't have to.

The idea is apparently being promoted by charity Karma Nirvana, that I previously wasn't aware of.  According to the news article linked above,
Its founder, Jasvinder Sanghera, was disowned by her Sikh family at the age of 16 after she refused to marry a man in India. She set up the charity in 1993, when she was 27.
And from the charity's website,
If you’re here to tell us that we can please all cultures without causing the slightest bit of offence - well, frankly, you’ve come to the wrong place.
I'll be in the UK next month, so it should be a good time for me to send some money their way.

Tuesday, 13 August 2013

Revisiting Pluto

Planetary astronomy is usually outside my sphere of interest, but I came across a paper last week that defied that trend.  As the title suggests, it returns to the decision in 2006 to reclassify Pluto as not being a planet.  To summarise for those who don't remember, the traditional set of nine planets was threatened by two consequences of modern telescopes.  First was the discovery of increasing numbers of planet-like bodies, including at least one as large as Pluto itself; second the realisation that Pluto was smaller than once thought, indeed likely smaller than Earth's moon.

Monday, 12 August 2013

Similarities

Quote from a news article about Gibraltar:
Spain also said it was considering taking the dispute to the UN Security Council, where it could seek the support of Argentina.
A Spanish government spokesman told the BBC that although the Falkland Islands - over which Britain went to war with Argentina - and Gibraltar were different issues, there were similarities between the two disputes.
The similarity, of course, is that the populations in both territories overwhelmingly prefer the status quo, and have repeatedly voted to that fact.  Self-determination; what's that?

Saturday, 10 August 2013

Little is Cute

I've previously talked on this blog about supersymmetry and extra dimensions.  Another class of models for new physics is the Little Higgs (LH) family.  While these models have faded out of primary focus in recent years, even before the LHC turned on, I always have a soft spot for them as they were the subject of my early research as a grad student.  So I tend to read, browse, or at least skim new work in this area, and that's the subject of this post: a paper from the end of July on new dark matter constraints in LH models.

Tuesday, 6 August 2013

The High Ground

Browsing the news, I came across this little article:
The US has criticised a new internet decree in Vietnam that would restrict online users from discussing current affairs.
The law, announced last week and due to come into force in September, says social media should only be used for "[exchanging] personal information".
As we all know, the correct course of action is to allow people to discuss things online, but record all communications.  That way, when you need to lock someone up for being a troublemaker, you'll have so much evidence there must be something you twist into a case against them.

England Retain Ashes

Sometimes, it's good to be a Brit living in Australia.

Monday, 5 August 2013

No Winos

Oh yes, I have a blog.

Yes, it's been a while since I've written anything here.  There's a number of reasons, but the main one is simply lack of time.  Not exactly dramatic, but sometimes that's the way it is.  I'm now hopeful that I can make at least semi-regular updates again.

I'll start with an overview of a couple of recent research papers, that came out in the same week with very similar results.  They relate to the Winos of the title, which is pronounced "weeno", not "weye-no".  Winos are particles that show up in supersymmetric theories (hence the suffix -ino) and are partners of the W and Z bosons.  They are also one of the possible dark matter particles in these theories.  The thrust of the two papers I'm considering, "Wino Dark Matter Under Siege" and "In Wino Veritas", is that these are ruled out in that role.

Sunday, 16 June 2013

Winter

So, I finally returned to Melbourne on Tuesday, after over nine weeks of travel.  It's been fun, with a nice selection of conferences, as well as seeing new places and old friends.  Of course, now that I'm back I have little excuse to not be hard at work.  In particular, I have three projects in progress that need to be completed soon, two of them having run to well over a year in length.  Unfortunately I'm still horribly jet-lagged from my travel; I've only managed to rise before midday once since my return, and that hurts my output.

Sunday, 2 June 2013

Religious Leader is Homophobic Bigot

Something of a Dog-Bites-Man title, I know.  But this time, the religion is the fuzzy, liberal Church of England.
Same-sex marriage sets a "dangerous precedent" which could lead to sibling marriage or polygamy, says Lord Carey.
Ahead of the Lords debate on the bill next week, the former archbishop of Canterbury argued there could be "unintended consequences".
He has previously courted controversy by likening critics of gay marriage to persecuted Jews in Nazi Germany.
As you can see, strictly speaking Carey is not a religious leader any more, having ended his tenure as Archbishop of Canterbury eleven years ago.  Though I'm pretty sure the only reason he gets to sit in the House of Lords is because of his religious role.  I also note the casual way that polyamorous1 relationships are automatically seen as wrong2.

Thursday, 30 May 2013

Congratulations

I'd just like to offer my congratulations to Vincent Audin and Bruno Boileau for becoming the first same-sex couple to wed in France.  Another useful reminder that sometimes, things can get better.  May many other French couples be able to follow and gain the happiness of a full legal union.

Monday, 27 May 2013

Never Miss a Trick

Ah, Labour.  Just when I was warming up to you again after the Blair/Brown years, you show excellent timing.
Labour and the Conservatives could unite to push through the controversial communications bill despite Lib Dem objections, a former Tory leader says.
The bill, allowing the monitoring of all UK citizens' internet use, was dropped after a split in the coalition.
But Lord Howard said David Cameron had "to act in the national interest" following the Woolwich murder.
Labour leader Ed Miliband has said that "if he [the PM] wants a communications bill, we'll help him get it through".
Never let it be said that the Americans are the only ones to respond to a terrorist incident with a broad suppression of civil liberties.
The Communications Data Bill would have given police and security services access, without a warrant, to details of all online communication in the UK - such as the time, duration, originator and recipient, and the location of the device from which it was made.
But it's okay!  Only the guilty have anything to fear from the police.  There is, of course, no reason to want privacy apart from the desire to conceal your criminal actions.  If you're not willing to do something in public, it must be wrong.  And sarcasm will be a capital offence.

Saturday, 25 May 2013

Planck 2013 Summary Talk

There's one talk left at Planck this year, the summary/outlook talk.  But I've decided I don't feel like live blogging this one.  Sorry!

Friday, 24 May 2013

Planck 2013 Day Five Live Blog 3

Lunch ran long, so I missed the first  two talks.

Planck 2013 Day Five Live Blog 2

Okay, some much-needed coffee and it's time for the second session of the morning.

Planck 2013 Day Five Live Blog

Final day of the conference, and we're back to purely plenary (including review) talks.  As I have every day I pass on the first review talk.  There doesn't seem to be an obvious theme of the day.

Thursday, 23 May 2013

Planck 2013 Day Four Live Blog 2

Last parallel session of the conference, and I'm staying with the Higgs talks.  Even if this session will run till 6pm.

Planck 2013 Day Four Live Blog 1

So, last night was the conference banquet and this morning we had string theory talks.  A combination of events that gave me little motivation to attend and less to pay any attention, hence no blogging from me.  After lunch, we have the last set of parallel talks, and I think I'll be attending the Higgs talks.  My own talk here was on a similar subject, albeit off in one of the BSM sessions, and it is an obviously exciting area right now.

Wednesday, 22 May 2013

Planck 2013 Day Three Live Blog 4

Last parallel session of the day, and I'm going to the Dark Matter session.  Conference Website.

Planck 2013 Day Three Live Blog 3

We kick off the afternoon talks with a parallel session on BSM physics.  Conference Website.

Planck 2013 Day Three Live Blog 2

Second morning session, after a much-needed coffee break.  We continue the study of flavour physics.  Conference website.

Planck 2013 Day Three Live Blog

Once again, I've come into the first review talk halfway through, so I won't comment on it.  Well, other than to note that despite having an hour, he still managed to run ten minutes over.  The theme of the morning is flavour, a topic I never find as interesting as I should.  Conference website.

A Small Thought

It seems to be currently popular to compare UK Prime Minister David Cameron to John Major.  For example, this was raised directly to him in a recent Today programme interview, see here.  This is unfair.

Not only did Major win an outright majority in parliament, more people voted for his Conservatives in 1992 than have voted for any political party in UK history.

Tuesday, 21 May 2013

Power

Unfortunately, I'm going to have to stop my live blog as my laptop is running out of power.  The lack of power outlets in the lecture halls strikes again!  Tomorrow, I'll be sure to charge up fully in the morning.

Planck 2013 Day Two Live Blog 3

After lunch, for the first parallel session of the conference.  I've chosen to go to the LHC session before the coffee break.

Planck 2013 Day Two Live Blog 2

Second Plenary session, first after the crucial coffee break.  Conference website.

Planck 2013 Day Two Live Blog 1

The first talk of the day was a cosmology/dark matter review.  I arrived late, halfway through the talk, and it was explicitly a review so I left this talk alone.  We follow this with the first plenary talk of the day.

Planck 2013 Day One, Live Blog 2

A fourth parallel session of the day.  Conference website.

Planck 2013 Live Blog: Day One

Okay, this post technically isn't a live blog.  I unfortunately missed the morning sessions, due to a combination of jet lag, lack of sleep and not being able to find the conference.  I did manage to attend the first session after lunch (the third plenary session), but I did not have internet access at that time as I hadn't registered.  But I did take notes, with the intention of putting them up later.  Conference website.

We had three talks: a good if slightly unclear advert for a linear collider; an inflationary talk that I found a bit hard to follow; and a talk that was half software-advert, half the-CMSSM-isn't-ruled-out-yet-honest.

Tuesday, 14 May 2013

Good News Round Up, Marriage Edition

Minnesota legalizes gay marriage:
With deafening cheers and overwhelming emotion, the Minnesota Senate voted 37-30 to legalize same-sex marriage.
“Today, love wins,” said Sen. Tony Lourey, DFL-Kerrick.
Technically it still needs to be signed by the Governer, but he has long stated his willingness to do so.

Hong Kong woman wins right to marry:
The Court of Final Appeal ruled that Hong Kong's current law, which barred the transsexual woman from marrying her male partner, is unconstitutional.
It's nice to remember that things can get better.

Monday, 13 May 2013

Yet Another Shooting

Oh look, its another shooting incident in the USA.
As many as 12 people have been shot during a Mother's Day parade in the US city of New Orleans, police say.
Police Supt Ronal Serpas told reporters that three or four people required surgery but no deaths are reported.
The victims included a 10-year-old girl who suffered a minor wound, he added.
It is unclear what sparked the shooting, which happened in the city's 7th Ward on Sunday afternoon. Police say two or three suspects were seen fleeing the area.
As usual, I have mixed feelings.  On the one hand, the US has made it clear that they value guns over innocent lives many, many times, and it won't be my children who are sacrificed to the Great God Second Amendment.  On the other hand, I'm not as lacking in basic humanity as the previous sentence suggests; plus I have American friends, who I'd like not to get randomly shot one day.

Brookhaven and Pheno Review

With these two conferences behind me, and my trusty laptop back in my hands, I'd like to briefly reflect on them as a whole.  Both conferences were, unsurprisingly, quite similar; same general area, same length, same structure, even a few of the same talks, most notably from Marc Kamionkowski on cosmology.  The biggest difference between the two was size, Pheno having at least twice as many participants.

What, then, can we take away?

Monday, 6 May 2013

Pheno 2013 Live Blog

I am abanding this live blog, as it is impossible on this total piece of shit tablet.  I leave what is below for posterity.
I'm unfortunately on a tablet right now, which will be a problem.

Talk 1: Cristina Blino: SM Results from LHC

We start with a review of theSM results from the LHC.

Actually, we start with some bad feedback, but that's been fixed now.

Usual stuff, namely illustrating the challenge that the experimentalists must face with pile up, for example.  It convinces me; I think the whole thing is black magic.

Standard Model  background to the interesting stuff, but it describes the data so qell over so many orders of magnitude that it is really a bit too good.

Writng on this tablet is awful.

Despite the LHC being a hadronic machine, and thus not clean, the high luminosity has already let to some impressive precision, especially for the gauge bosons (leptonic modes).

Forward-Backward asymmetry in lepton pair production.  Any asymmetry at LHC is tricky, due to symmetric initial state.  Measured, agrees with lepton machines; relevant for future studies of ttbar asymmetry.

W-photon production slightly in excess of theory; look into this later.

Triple gauge couplings are a common result; I don't actually know what models would show up there.  Limits improve, of course.

One problem with some of these plots for diboson production, is that it's not clear if theoretical errors are shown.  Some of jh the measurements are slightly off the theory lines, but I expect there's still one-sigma agreement.

Top Quark:
  • One top pair per second.
  • Cross Section already systematics-dominated.
  • Ah theory errors shown here.  Even the small difference from 7 to 8 TeV cross section can be resolved.
  • Single top; errors here still relatively large.
First talk runs long.  Not an auspicious opening.

In summary, we have a terrifying array of data, with precision and agreement with theory that is both impressive and intimidating.  The most interesting result I saw was the W-gamma measurement, which probably isn't significant but right now we can't be too picky.

Talk 2: K.K. Gan: BSM searches at LHC

The obvious folow-up to the previous talk.

I really fucking hate trying to write on this tablet.  I'm spending far tpo much time fighting the fucking interface.  And forget correcting typos, that would imply being able to move the fucking cursor, and clearly that's an unreasonable functionality to expect.

SUSY: standard motivations.
  • Stop searches; leptons plus MET.
  • The degenerate slices still exist.
  • Coverage away from that is pretty good.  Exclusion up to order 400 GeV.
It's notable how the results immediately fpocus on stops.  No time wasted on traditional searches.  That's  the time we live in.
  • Heavy stop pairs, decaying to stop plus Z.  Gah, missed the limits there.
  • Gluino pair production, decaying to stops.
  • The usual TeV exclusion.
  • Two things occur to me.  How much wiggle room remains in the degenerate regimes, and can such a specyrum even arise in a top-down manner?
  • The pMSSM papers can probably answer that first question.
  • Squark and sbottom searches slightly underperformed expectations.  Interesting.
  • Electroweak production; chargino-neutralino production.  Three leptons, clean to compensate low cross section.
  • Limits on LSP up to 200 GeV for appropriate spectrum.  Chargino to 600 GeV for same assumptions.
  • Just lost a minute trying to make this thing work.  Fuck.
In summary: SUSY continues to look dead.  Lecture says don't worry; we can never exclude SUSY,so we have plenty of job security!

  • Exotica: Z primes?  Really, not very exotoc.  Of course, eady for experimentalists thanks to leptons.

Saturday, 4 May 2013

Brookhaven Forum Day 3 Blog II

Final session of the conference.  Conference Website.

Talk 3: 10:50am: Lloyd Knox, "The Universe According to Planck"

With Planck having recently presented results, it is natural to have a review from a member of that collaboration.

The better experiments always have the funkiest animations.

Did he just say the released data is only 40% of what they took?  I thought almost all results were out.

Detection of gravitational lensing at the absurd 25 sigma.

The usual argument for the origin of the density fluctuations, seen in the CMB and seeding structure formation, but the slides are quite nice.

LambdaCDM fits the data with ridiculous non-trivial precision.  Things that are needed and have no free parameters:
  • Neutrinos
  • Neutrino cooling
  • Helium (for BBM consistency)
  • Non-equilibrium recombination
  • Gravitational lensing

Sound horizon at surface of last scattering:
  • Directly measured from CMB
  • Imprints itself in large scale structure, c.f. BOSS experiment.

Constraints on Non-Gaussianity.
  • Inflation, of course, predicts small non-gaussianity in almost all models.
  • Some non-Gaussianity inevitable from gravitational interactions, so measurements all relative to that.
Interesting statement; there is a small tension in the value of H0 measured at Planck and at other experiments, but this can be ameliorated with additional light (relativistic) degrees of freedom.  I must look into this in more detail.

So in summary, everything works.

Talk 4: 11:30 am: Juan Maldacena, "Recent Advances in Formal Theory"

So to end the conference we have the traditional big name to keep people's attention.  I've never heard Juan speak, so I don't know what to expect.  I do worry that this subject might be a bit too much for me after a late night drinking yesterday, though; we'll see.

  • QFT works; we haven't seen any violations at the LHC etc.
  • There nonetheless remain some theoretical problems, gaps in our understanding.
  • Computational techniques; we've seen some of that here already.
  • Strong couplings; strings?
  • Fixed points and renormalisation flows; I recall the recent kerfluffle over the a theorem.
  • No surprise that AdS/CFT is brought up!
The topology of this talk is multiply-connected.

SUSY:
  • The extra symmetry often makes the theories simpler; no surprise to see N=4 SYM brought up.
  • Work in N=2, N=1 and even N=0 :)
N = 4 SYM:
  • Maximally supersymetric U(Nc) QCD with coupling g
  • All fields lie in the adjoint representation
  • Planar limit: Nc to infinity, g^2 Nc fixed
Connection to strings: chain of gluons behaves like a string; closed strings are glueballs.  The string coupling goes like 1/Nc, hence the planar limit is the very weak coupling limit.

Discussion on loops in RGE flows; will we get enough details?  No, just a quote of the proof.

Some discussion on entanglement that seems to be related to the black hole entropy, and the way in which surfaces seem to describe the volumes they contain.  My head is dropping, though, and I didn't manage to follow the details.

Friday, 3 May 2013

Brookhaven Forum Day 3

Unfortunately, I missed the first talk this morning on direct detection of dark matter.  I'm really not much of a morning person in general, and the last day of a conference is always a bit tricky because you start to flag.

Still, ready for the second talk of the day.

Talk 2: 9:40 am: Tracy Slater, "Dark Matter Phenomenology and Indirect Detection"

Brookhaven Forum 2013 Day 2, Live Blog IV

Final session of the day, the "New Ideas/BSM" session.  Conference Website.

Brookhaven Forum 2013 Live Blog: Day 2, Blog III

After that slightly disappointing (from my point of view) plenary session, its time for the parallel sessions.  The ability to select which session to attend should ensure I'm listening to relevant talks, I hope!  In particular, I've decided to hit the Higgs/BSM talks for the first session this afternoon.  Conference Website.

Brookhaven Forum 2013 Day 2 Blog II

This session is more on strongly interacting stuff, so I'm less optimistic, this being somewhat away from my primary interests.  We'll see.

Thursday, 2 May 2013

Brookhaven Forum 2013 Day 2

So, yesterday was a pretty good day that reminded me just how much I enjoy conferences.  Hopefully today can continue to deliver.  Conference Website

Brookhaven Forum Live Blog IV

First Parallel session.  Conference website

Abhishek Kumar, Searching for Very Light Stops
  • Stops relevant for naturalness, take the case m_stop < m_top.
  • Non-standard stop decays: b-W-neutralino with W on/off shell, c-neutralino.
  • Use MFV to handle the flavour-violating decays.
  • Flavour-violating decay can dominate over four-body decay, even when both are allowed.  Depends on left/right handed nature of lightest stop.
  • ISR needed to account for MET properly.
  • Limits up to ~250 GeV.
Sujeet Akula, Gluino-driven Radiative Breaking in Grand Unified Supergravity
  • Pointed towards Higgs to two photons, among other things, as evidence for light sleptons
  • Of course, also lots of things that push SUSY scale up.
  • Good talk, but too long on the background.  Get to what's new before you run out of time!
  • Basic structure: gluino mass at GUT scale is much larger than the other soft masses.
  • Heavy gluino drives squarks heavy and radiatively breaks EWSB.
  • Higgsino mass mu also driven large.
  • Large seems to mean a factor of 10.
  • Non-universal gaugino masses need non-trivial GUT-scale Higgses.
This is claiming a lot for only tweaking the CMSSM by one number.

Eva Popenda, Squark Pair Production at NLO matched with Parton Showers
  • NLO standard is Prospino, which assumes that all squarks degenerate.
  • Go beyond that for the first time in an event generator.
  • This is all a bit technical for me.
  • Even when squarks degenerate, subchannel cross sections disagree: Prospino assumption (all subchannels identical) not exact.
  • NLO corrections can give ~20% corrections to shapes of distributions.



Brookhaven Forum 2013 Part III

First session after lunch, and we have a cosmology talk from Marc Kamionkowski.

Brookhaven Forum 2013 Live Blog II

New session, new blog.

Wednesday, 1 May 2013

Brookhaven Forum 2013 Live Blog

For the next two-and-a-half days, I'm attending the Brookhaven Forum 2013.  I was here three years ago, and enjoyed it then.  Sadly I had to miss the last meeting, but I'm glad to be back.  I'm not expecting anything dramatic here, but I'm going to live blog the conference in lieu of taking notes.  This way, I might actually go back and look at what I've written before!

Thursday, 11 April 2013

California: 13

So, at current time of writing I'm in a different time zone, continent and even hemisphere to the usual.  Yes, if the title didn't give it away I've travelled to the USA, where I'll be for the next six weeks before moving on to Europe.  Obviously, my blog posting will be unreliable, but what else is new?  I actually expect to get more written now I'm actually on the move than was the case in the last couple of weeks.  For someone who travels a fair amount, I'm very bad at preparing for it; I always get highly stressed right up to the point where I check in at the airport.

This is my first time in California, and it's the thirteenth US state I've visited.  I'm not counting states I've only travelled through; connecting at LAX doesn't let me see anything different from any other major airport, for example.  Thankfully, I'm not in the south of the state, instead in the San Francisco suburbs.  This means I'm not suffering from the weather, a good thing after the Melbourne summer.  Indeed, with the weather hovering between lows of 10C and highs of 20C, I'm almost in love.

Tuesday, 26 March 2013

Another look at NetHack

So, nearly a year ago I offered my thoughts on NetHack, one of the classic roguelikes.  I wasn't a big fan, much preferring Angband, and indeed pretty much all the roguelikes I've tried.  However, after playing a lot of Crawl last year I decided to give NetHack another try.  I found both games to be similar even within roguelikes, and thought I'd see if my experience with the former helped me with the latter.  I had, after all, struggled to make any progress through the Mazes of Menace.

Well, I have changed my opinions slightly.

Testing Times (I)

I'm not a huge cricket fan, but I do like to follow test matches, especially England's. The recent series against New Zealand has definitely been on my radar, and ended in a pretty dramatic fashion today.  England scraped a draw in the third test, drawing the series 0-0, becoming only the third side to avoid defeat by batting through the final day, starting from four wickets down.  With New Zealand taking the eighth and ninth wickets with just three overs to go, it must have been incredibly tense in the stadium.

Thursday, 21 March 2013

Kenyan Condom Ad

Surprise, surprise, religious leaders are trying to cause actual harm, this time in Kenya:
A TV advertisement promoting condom use in Kenya has been withdrawn after an outcry by religious leaders, health official Peter Cherutich has said.
The argument is at least slightly less obnoxious than usual:
Christian and Muslim clerics said the advert encouraged infidelity, rather than safe sex to curb HIV/Aids.
I say slightly less, because infidelity can cause actual emotional harm, instead of the fictional harm often invoked (see: Roman Catholic Church, passim.)  But I get the feeling that this implied message is: cheaters deserve whatever punishment they get.  After all, sex is only acceptable in marriage as that is a great tool of social control what god wants.

Monday, 18 March 2013

One Year Anniversary!

So, I've managed to stick with this blogging thing for a year.  With 120 posts, that's nearly one every three days!  Unfortunately they tend to be rather clumpy, with far to many dead weeks.

It's been an eventful year for me; I travelled to a different continent and, indeed, hemisphere; started a new job; had an abstract rejected from a conference for the first time (boo!); learnt that I really, really need to get air conditioning for my apartment; and attended my first conference in a non-English speaking country.  It's also been an interesting year in particle physics, with the discovery of the Higgs providing a lot of excitement but the lack of hints for BSM physics casting a shadow over the field.

Looking to the year ahead, then, here's to a more regular update schedule here; more papers this year than the last; and hopefully something pointing to new physics from our experimental colleagues!

Tuesday, 5 March 2013

A Clear Statement of Intent

From the BBC:
Chancellor George Osborne is in Brussels determined to renegotiate the European Parliament's proposals to curb bankers' bonuses.  But EU finance ministers in the Economic and Financial Affairs Council (Ecofin) are expected to approve last week's proposals.  They include limiting bonuses to 100% of a banker's annual salary, or to 200% if shareholders approve.  The City of London fears the rules will drive away talent and restrict growth.
I mean, just imagine what the British economy would be like right now without the bankers.

Monday, 4 March 2013

Collider Searches for Dark Matter

The quest to find non-gravitational evidence for dark matter proceeds along several different fronts.  The most direct approach is to look for dark matter particles scattering in detectors here on Earth.  Indirect searches, looking for cosmological signals of dark matter annihilation or decay, has provided a number of tantalising hints, of which the "line" signal at Fermi is the most recent.  However, directly producing dark matter at experiments like the LHC offers us the most control over the initial conditions and thus the least ambiguity in interpretation.

The problem with dark matter at collider experiments is that it is dark, i.e. it doesn't show up in the detectors.  To get around this problem we look for the production of other stuff as well as the dark matter itself.  We can then tell if the dark matter is there by seeing an apparent violation of conservation of momentum; the missing momentum is carried away by the unobserved dark matter particles.

The traditional approach to these type of searches is to take a complete model of new physics (such as supersymmetry) and use that to model the production process.  So in SUSY, we produce gluinos or squarks, which then go through a several-step decay producing dark matter and multiple Standard Model (SM) particles.  Indeed, even today the signal "jets and missing transverse momentum" is considered a characteristic SUSY search.

However, a couple of years ago an alternative and somewhat opposite approach began to become popular.

Tuesday, 26 February 2013

Living in the Wrong Country

I noticed a news story on the effects of poor sleep today:
A run of poor sleep can have a dramatic effect on the internal workings of the human body, say UK researchers.
The activity of hundreds of genes was altered when people's sleep was cut to less than six hours a day for a week.
... 
Heart disease, diabetes, obesity and poor brain function have all been linked to substandard sleep.
What missing hours in bed actually does to alter health, however, is unknown.
Which struck a chord given what I've experienced over the last few weeks.  My apartment doesn't have air conditioning, indeed seems to have been built to keep heat in.  And so I've been struggling to get to sleep, and waking up during the night, thanks to being too hot.  All in all, I'm more of a cold weather person.  Which does rather bring to mind the question: why did I decide to move to Australia?

I'm invoking these conditions as my excuse for not posting anything recently.  Still, it is supposed to cool down for the rest of the week, which will strip me of that excuse hopefully let me get  something substantive out.

Now if you'll excuse me, I'm off two inches in front of my fan.

Thursday, 14 February 2013

SUSY Mass Upper Limits

Supersymmetry remains the most popular theoretical extension of the Standard Model of particle physics.  It's not hard to see why; in addition to its structural appeal, many people have spent years working on it.  With all that time invested, a minor detail like it not showing up at the LHC is hardly going to dissuade us.

What has changed is the perspective we take, especially as far as the motivation for supersymmetry is concerned.  The traditional arguments about avoiding regions of theoretical fine-tuning have taken a battering from the combination of the observed Higgs mass, and the high exclusion limits on superpartner masses.  These already force most models to be tuned to at least one part in a thousand, often worse.

But once we abandon fine tuning as a motivation for supersymmetry, we also remove one of the main arguments for electroweak supersymmetry; that is, for the superpartners to be light enough to show up at the  LHC.  And this is reflected in recent model building, with theorists increasingly willing to consider models where some or all of the superpartners are heavy; for example, mini-Split SUSY models put most of the new scalar particles at a hundred to a thousand TeV, with the new fermion masses around one to ten TeV.

Against this, a recent paper develops some interesting arguments for upper limits on superpartner masses.

Cars Kill Cities

An interesting article that's being doing the rounds suggests that cars are bad for cities:
In the early 1960s – when highway construction was at its peak and cars were just beginning to leave their mark – a handful of critics predicted there would be irreconcilable tensions between vibrant cities and their motorized inhabitants. Nearly 50 years later, researchers at the University of Pennsylvania published research validating this idea.
The essence of the argument is that cars need places to park.  Space devoted to parking is not devoted to people, in the form of commerce and other sources of employment.  In short, cities should prefer public transit over cars as the primary means of commuting.

Thursday, 7 February 2013

Gay Marriage Passes!

I know I'm running a little late on this, but the news that the House of Commons passed gay marriage is fantastic.  While civil partnerships offered same-sex couples effectively all the rights of marriage, and the government had proven itself willing to enforce that, recognising that hetero- and homosexual unions are fundamentally the same is a significant moment.  It seems odd that, within my lifetime, a Conservative government should have passed Section 28; and within my memory, there were scandals over homosexual members of a Labour government.  It's always nice to be reminded that things can get better.

Monday, 28 January 2013

New LEP Paper

Twelve years ago, LEP -- the Large Electron-Positron collider -- finished taking data.  That's so long ago I was still an undergraduate, YouTube and Facebook didn't exist and even Google was relatively unknown.  So I was quite surprised to see a new paper on the arXiv from the LEP collaborations.

Not So Great

I've been living outside of the UK for over a decade now.  In the last couple of years, I've started to notice ads as part of the 'Great Britain' campaign, aiming to raise the profile of the UK for tourism, industry, investment and so on.  I don't remember ever seeing anything similar before this, so at the least it's a more aggressive promotion than recently.  The government obviously realises that in a global market you have to compete with other countries for these things.

Sometimes, you've got to laugh.
Please don't come to Britain – it rains and the jobs are scarce and low-paid. Ministers are considering launching a negative advertising campaign in Bulgaria and Romania to persuade potential immigrants to stay away from the UK.
The plan, which would focus on the downsides of British life, is one of a range of potential measures to stem immigration to Britain next year when curbs imposed on both country's citizens living and working in the UK will expire.

Wednesday, 23 January 2013

Quote of the Day

Physicists are only human (honest).  We like to crack the odd joke, even if our sense of humour can be a bit odd.  I have a friend whose advisor once put Harold Ramis in the acknowledgements of a paper on removing ghosts. There seems to be a competition going on in astro-ph for the most absurd paper title.  And then there's what I came across today, reading an old paper from the CTEQ collaboration.  Buried on page 6 was this little gem:
The two-part structure of χ2 loosely resembles a bicameral legislature such as the US Congress, where votes in the House are proportional to population—data points in our case—while votes in the Senate represent specific entities—experiments or data sets in our case.
At least it's not the House of Lords.

Monday, 21 January 2013

Physics at Different Scales

Back in November I wrote two posts about the problem of infinities in quantum field theories.  In the first of those, I introduced the two types of infinities that arise: infrared infinities, that happen when a kinematic variable goes to zero; and ultraviolet infinities, that come from the need to integrate (sum) amplitudes over an infinite volume.  In the second post, I explained how infrared divergences are resolved: the infinity occurs in something that is unmeasurable.  For example, it is impossible to distinguish between the production of an electron-positron pair, and the production of the same two particles plus a photon, if the energy of the photon is very small.  When making predictions, we need to include not only the things we do observe, but also the things we cannot; only then can we get well-defined answers.

Today, I want to return to this mini-series and discuss ultraviolet infinities.  I hope to outline the solution to this problem, which is a bit trickier.  This will lead on to the point I really wanted to get to from the beginning, which I'll have to leave for a final post by the end of the month.

Friday, 18 January 2013

Tasmania

So, after commenting on how I hoped to stay more current with this blog at the start of the year, I went silent for a week and a half.  I do have an excuse; I was travelling around Tasmania on a fairly impromptu vacation. A good chance to get out of town for a few days and see something different, but my net access was limited.  Now I'm back, somewhat refreshed and feeling better for it.  I would have posted explaining things before I left, but my connection here went down the night before.

I hope to make a more substantive post over the weekend, but not about my trip.  I don't plan to turn this blog into What I Did On My Holidays -- no plans to start a revolution.  Although, after living in Australia for several months, I have finally seen a kangaroo!

Sunday, 6 January 2013

Age of Wonders

Sometimes, you have to stop and remember just how amazing the modern world is.  For example, this recent story about the first UK hand transplant:
A former pub landlord from West Yorkshire has become the first person in the UK to have a hand transplant.  Mark Cahill, who is 51, had been unable to use his right hand after it was affected by gout.  Doctors say he is making good progress after an eight-hour operation at Leeds General Infirmary.  It is still very early to assess how much control of the hand will be gained - so far he can wiggle his fingers, but has no sense of touch.
Transplants have become commonplace, almost boring.  But really: we're talking about replacing someone's hand.  There's a lot of stuff going through the wrist; blood vessels, nerves, muscles; and we (as a species) can connect that?  And make it work?

Hell, I didn't even realise till reading the article that this is not that new; the first hand transplant was almost fifteen years ago.  Just as long as we can avoid the world of Gil `the ARM' Hamilton.


Child Benefits

One inevitable consequence of living in another country is that you don't always stay on top of politics at home.  For example, yesterday I saw an article on the BBC about UK child benefits:
Some 200,000 people - of 1.2 million - have opted out of receiving child benefit, ahead of changes on Monday.  Treasury Minister David Gauke said that was "slightly above" what was expected.  Families with one parent earning more than £50,000 will lose part of the benefit. It will be fully withdrawn where one parent earns above £60,000.  But unless parents opt out of receiving it by the end of Sunday, higher earners will still get the benefit and will have to pay it back later.
The point of this news article is about how the changes to child benefits are working.  In particular, the system where benefits are by default paid but then must be repaid is not exactly efficient, and will probably be unpopular.  The fact that only one in six of the families affected by the new rules have acted suggests that the policy has not penetrated popular consciousness.

But as someone who hadn't seen the changes, I respond to them instead.

Tuesday, 1 January 2013

New Year, New Thoughts

I'm generally not one for New Year's Resolutions.  Still, this time around I do at least have an obvious one: update this blog more often.  It's not as if I'm lacking in ideas; I have several partially-written posts, some of them over a month old.  I also have several series I've started, that are currently orphaned.  (I do intend to get back to all of them.)

Part of the whole issue relates to work.  Last year was a bad year for me in terms of work, and when that's the case it's harder for me to feel motivated to work on the blog; this is, after all, a hobby.  That's why more regular updates are only my second resolution.  Related is the whole issue of reading; I talked about this early in December, and it was not until last weekend that I finally got on top of this again.  Right now, my to-read pile consists of three papers, all of which went up on the arXiv today.  To put that into perspective, a week ago I had thirty-four papers to read, some of which dated back to November.  Plus, there where an additional seventeen papers I felt it worth downloading from last week; you can guess what I've spent the holiday season doing.

In all, 2012 really wasn't a good year for me.  Sure, I started my new job, but I'm still not really comfortable with Melbourne; not in the way I was with Vancouver, at least.  My publication record was anaemic, I was rejected by a conference for the first time ever, and I still haven't properly explored my new home city.  What really hurts is I know the flaws that caused many of these problems, and more to the point I know I can deal with them better.  But on the flip side, that also means I can be hopeful that this new year will be better than the last.

Happy New Calendar Day to you all!