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Physics on film

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September 2008 Archives

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Enrico Saggese

By Michael Banks

Yesterday afternoon here at the International Astronautical Congress in Glasgow, I had a brief chat with Enrico Saggese, the controversial new commissioner of the Italian Space Agency (ASI). Saggese was recently installed by the Italian government after it sacked his predecessor (and one-time Physics World author) — Giovanni Bignami — following the mass resignation of the agency’s seven-member administrative council. The space agency is normally led by a president who chairs the council. But in August, prime minister Silvio Berlusconi replaced the council with a commissioner and deputy commissioner, discarding Bignami, who had been president, in the process.

I asked Saggese why Berlusconi changed the structure of the agency when Bignami was replaced. “There are situations which happen where you have to reorganise the agency internally”, Saggese explained rather opaquely, “but there are a group of people around me, such as a magistrate taking care of what I am doing, so I am not a powerful man.”

By Michael Banks

The weather was dry as I arrived yesterday at the armadillo-shaped congress centre in Glasgow for the 59th International Astronautical Congress. But there was no need for delegates to ask what the weather forecast would be for the rest of the week. Even before I had had the chance to register, I had already picked up two conference freebies. They were both umbrellas.

The IAC is a huge global meeting at which the international space industry and national space agencies come together to show their wares and find out what everyone is up to. In the afternoon, just as the first rain clouds were opening up, the heads of national agencies came together for a briefing session. NASA boss Mike Griffin was joined on the panel by other space-agency chiefs such as ROSCOSMOS deputy head Alexander Medvedchikov from Russia, the Chinese National Space Administration’s boss Sun Laiyan, Japan Aerospace Exploration Agency head Keji Tachikawa as well as Byrana Suresh, director of the Indian Institute of Space Science and Technology.

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The weakly bound rubidium molecules (upper image) are transferred into the rovibrational ground state with a STIRAP laser pulse. (Courtesy: Austrian Academy of Sciences).

By Hamish Johnston

Rovibrational ground states are a bit like buses — you wait a long time for nothing and then three come along one after another.

A few weeks ago, we reported on the first realization of a quantum gas of ultracold polar molecules by Deborah Jin, Jun Ye and colleagues at JILA in Boulder, Colorado.

The big challenge in creating the 350-nK gas was to put the potassium-rubidium molecules into their “rovibrational” ground state, where they have the smallest amount of rotational and vibrational energy allowed by quantum mechanics.

Normally, the molecules heat up the gas when they give up their excess rovibrational energy. Jin and Ye avoided this by using lasers to get the molecules to give up their energy as light that exits the gas without heating it — a technique called “stimulated Raman adiabatic passage” (STIRAP).

Now, Rudi Grimm and Johannes Hecker Denschlag at the Austrian Academy of Sciences have used the same technique to create an ultracold gas of rubidium-rubidium molecules in the “triplet” rovibrational ground state (Phys. Rev. Lett. 101 133305). Such a triplet state is interesting because the molecules have large magnetic moments, and therefore the gas could be useful as a “quantum simulator” of solid magnetic materials.

In the same issue of Physical Review Letters, Matthias Weidemueller and colleagues at Germany’s University of Freiburg explained how they created an ultracold gas of lithium-caesium molecules in the rovibrational ground state (Phys. Rev. Lett. 101 133304).

Like the potasium-rubidium, lithium-caesium molecules have electric dipole moments — which means that they could someday be used as quantum bits that are controlled by the simple application of an electric field.

By Hamish Johnston

Superfluid helium and magnetic fields are both in abundance in the Large Hadron Collider so it’s not surprising that some doomsayers have suggested that explosions called Bosenovae could occur in the accelerator’s cooling system.

Such explosions were first seen about ten years ago when an ultracold condensate of atoms was subjected to a carefully-selected magnetic field, which caused the normally-repulsive forces between atoms to become attractive. The condensate collapsed under these forces until it reached a critical density and then exploded outwards — much like an aging star becoming a supernova, but of course, on a much smaller scale.

So why couldn’t this happen in the LHC?

Well according to CERN’s Malcolm Fairbairn and Bob McElrath, this scenario is impossible because helium-4 atoms used to cool the LHC will simply not be attracted to each other when subject to any sort of magnetic field. The reason, according to the pair, is that the helium-4 nucleus does not have a magnetic moment and the atom has no unpaired electrons — both of which are needed to make the atoms attract each other.

Climate chaos

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By Jon Cartwright

A few years back after a particularly wet spell, Lenny Smith found that his local pub in Oxford had been flooded. This was of course bad news for Smith’s beer provisions, but for the pub’s owner the more desperate issue was that the flood waters had spilled into the basement and wrecked thousands of pounds worth of new kitchen equipment. So, asks Smith, how much should the owner spend on his kitchen next time? This is the sort of real-world decision related to climate change that he thinks can too easily be forgotten by climate modellers.

I was listening to Smith, a mathematical physicist (and an expert on chaos theory) at the University of Oxford, talk at the international conference on Climate Change Impacts and Adaptation at the University of Exeter, UK, yesterday. He was arguing that it is fruitless to mindlessly improve climate models in all areas. Rather, he said, we should investigate how robust current climate models are by checking for consistencies among them.

By Hamish Johnston

If you asked me to name an “outspoken” particle physicist, I might choose Tommaso Dorigo of Italy’s University of Padova. Dorigo, you may recall, was embroiled in a controversy last year over the supposed sighting of the Higgs boson by the CDF collaboration at Fermilab.

Dorigo is a CDF member and had discussed preliminary results from the experiment on his blog, where they were picked up by the press and reported as evidence of the elusive Higgs. While these results had been previously reported at a conference, they had not been “approved” by Fermilab for mass consumption.

Needless to say, the CDF data did not provide strong evidence for the Higgs, and Dorigo has been criticized for discussing the results in public.

Now, Dorigo spends most of his time working on the LHC’s CMS experiment — so what does he have to say about the recent setbacks at CERN?

Nothing it seems, and he has even made a point of saying so in a recent blog posting .

Dorigo observes “CERN appears a bit up-tight about the latest events…”, and claims “my blog is targeted as a possible source of leaks”.

As a result, he has chosen to keep quiet: “And if I play fair, maybe I am allowed to survive here, and maybe one day I will stop being threatened every other day, in the name of protecting internal information of the experiments I am part of”.

Strong stuff…so, once burned, is Dorigo making the right choice?

By Jon Cartwright

Many of you will be wondering how the Large Hadron Collider (LHC) has been getting on since last Wednesday’s celebrated “switch on”. Well, if you are willing to overlook one 30 tonne hitch, commissioning is still going well.

On the switch-on day itself, if for some reason you left the planet, the operations team managed to get proton bunches all the way around the LHC’s 27 km-long ring in both directions. But even though the media had trickled away by early evening, the LHC team didn’t stop ploughing ahead, as I discovered when I went to the control centre the morning after. By then they had already had an anticlockwise bunch endlessly circulating, albeit spread or “de-bunched” around most of the ring. To correct the de-bunching, the team initiated their radio-frequency systems, which by Friday had been successfully tuned in both frequency and phase.

Friday, unfortunately, also brought difficulties. A transformer weighing some 30 tonnes developed a short circuit, forcing the team to replace it. As I hear from Lyn Evans, the LHC project leader, the new transformer has been lifted into place and the electrical systems, which feed the vital cryogenics systems, should soon be back on line.

The good news, however, is that Evans is planning to try some low-energy collisions next week. Hang on to your hats.

By Hamish Johnston

Have rocket scientists built ‘financial weapons of mass destruction’?…

The answer is yes — at least according to the investment guru Warren Buffett, who has been warning for some time that complex financial instruments such as ‘derivatives’ are far too complicated for mere mortals to understand. Indeed, five years ago Buffett described derivatives as a “financial weapons of mass destruction”.

Now that derivatives have apparently helped bring down one of the world’s largest investment banks, should the rest of us be blaming the rocket scientists — PhD physicists and other bright sparks — who helped develop these financial instruments and the mathematical algorithms needed to make sense of them?

In an 1999 editorial, then Physics World editor Peter Rodgers weighed the pros and cons of physicists abandoning careers in research for high-paying jobs in finance. Would the raised profile of physics in society offset the loss of talented people from academia?

What Peter didn’t ask was: “What if the rocket scientists make a mess of it?”.

Avarice, not algorithms, is of course to blame for the credit crunch, but one can’t help wondering if this is the end of the love affair between physics and finance?

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Ready for action at the LHC (Courtesy: BBC).
By Hamish Johnston

Clearly the world didn’t end earlier today when the first protons made their way around the LHC.

But what if something unexpected had happened…what if physicists (including our own Jon Cartwright) started vanishing and what if something was lurking in the accelerator tunnel…who would we turn to?

Torchwood’s Captain Jack, of course, who will be leaping from the tallest toroids later today in a special radio edition of the Dr Who spin-off set at the LHC.

You can listen to Torchwood: Lost Souls on BBC Radio 4 today at 14.15 BST and for the next seven days as a podcast.

And for more LHC fun, check out this story in The Sun: Boffins in ‘Doomsday’ rap

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The LHC control room (heavy lever obscured from view).

By Jon Cartwright

Until a few months back I had an excited vision of the moment the great LHC “switch on” would take place. Here’s how it goes: The control room, normally frantic with the workings of scientists, falls under tense silence as a lone technician grips a heavy lever. Just as the quiet becomes unbearable, the director general mutters: “OK, let’s go.” Beads of sweat trickling down his temples, the technician heaves back the lever while averting nervously to a dial that has coloured bars going from green to yellow to red (450 GeV…5 TeV…7 TeV…DANGER) . “Faster!” cries the director general, his eyes glowing with a sort of manic intensity, “Faster!” Then the control room begins to shake and the scientists dive under their workstations to avoid the plaster and tiles falling from the ceiling.

Needless to say, the real event tomorrow will not satisfy onlookers with any cinematic clichés (and nor will the beams break any speed records — they will be strictly cruising at their injection energy of 450 GeV). But that’s not to say the event will be without drama, as I found out today when I went to CERN’s Meyrin site for for lunch with Paul Collier, head of the accelerator operations team.

“It’s not like blasting off from Cape Canaveral,” he said, referring to the fact that there is no definite countdown for performing certain tasks. Rather, the operations team will be learning as it goes, and we will get to watch — milestones, mistakes and all. The current plan is to inject the first beam into the ring at around 9:30 am, but it could happen anytime between 9 and 10 am (keep an eye out on this blog for the decisive moment). From then on, the team will take the beam round the LHC’s 27 km-long ring in a dozen or so sections, each initially fenced-off by a physical barrier.

By Jon Cartwright

In my last blog entry on the Large Hadron Collider (LHC) I asked if CERN could make it to Wednesday without any further difficulties. Well, there’s been one — a thunderstorm-induced power cut that took out the cryogenic systems for the weekend — but other than that it’s all systems go for the eagerly awaited “start up”.

On Friday evening, according to CERN spokesperson James Gillies, the LHC operations team successfully performed a third and final synchronization test. Unlike the previous two tests, which concerned “kicking” proton beams from the Super Proton Synchrotron into the LHC’s ring, the aim on Friday was to make sure the protons could be booted out of the ring at the “beam dump” point located between sectors five and six. The latest test also demonstrated that the team could navigate the protons around two sectors, or about 7 km. That means they’ve already reached 25% of their target for Wednesday, when they plan to get a low-energy beam cruising around the 27 km ring in one direction.

Talking about Wednesday, physicsworld.com is now reporting from CERN to bring you all the news in the run-up to the big day. You can also expect an analysis of the events in the October issue of Physics World.

By Hamish Johnston

You would have to be living under a rock in the UK not to know that the Large Hadron Collider will be fired up next week at CERN in Geneva. BBC Radio 4 is dedicating an entire day of programming to the LHC (called ‘Big Bang Day’), and this is being promoted with great fervour across the corporation’s many TV and radio outlets.

This morning Chris Llewellyn Smith,former director general of CERN, was on Radio 4’s Today Programme to reassure listeners that the world will not be destroyed by a black hole — or turn into a “strange goo” — when the LHC is switched on.

Meanwhile over on Radio 5 Live, CERN physicist John Ellis was chatting about his new paper  ‘Review of the safety of LHC collisions’ with host Nicky Campbell. This is surely the first time that an article in the Journal of Physics G: Nuclear and Particle Physics has been deemed to have the same news value as the latest exploits of Newcastle United’s ex-manager Kevin Keegan.

Indeed, one could be forgiven for thinking that the LHC is ‘brought to you by the BBC’. In today’s Times, gossip columnist Adam Sherwin suggested that the LHC start-up date was pushed back to 10 September because BBC superstar Andrew Marr — who will be presenting live from CERN on the day — is on holiday this week. The BBC has denied exerting undue control over the world’s largest physics experiment.

Another ‘quality daily’, The Independent, ran the headline ‘It’s sex and drugs and particle physics as D:Ream star recreates the Big Bang’ earlier this week. For those too young to remember, the article refers to Brian Cox, who is sort of a Liam Gallagher of particle physics and one of the many stars that the BBC will be rolling out next week.

And leave it to The Sun to say: ‘End of the world due in nine days’ …unless Andrew Marr decides to extend his holiday, of course.

By Jon Cartwright

Physicists used to be able to show preliminary results at conference presentations, safe in the knowledge that no-one would steal their data. Now, with the advent of the “physics paparazzi”, things have changed.

It started a few weeks back when, at a high-energy physics conference in Philadelphia, a member of the PAMELA team flashed a slide that depicted an excess of high-energy positrons in the ionosphere. Although several conference attendees suggested the positron excess could be evidence for dark matter — the elusive substance thought to make up some five-sixths of all matter in the universe — the team did not make the slide available to journalists or other scientists.

That, however, didn’t stop Marco Cirelli of CNRS in France and Alessandro Strumia of INFN in Italy. Those attendees managed to take a snapshot of the slide during its momentary disclosure and use the picture as the basis for an analysis which they published on the arXiv preprint server.

By Hamish Johnston

On 16 August Usain Bolt sprinted to gold in the 100 m dash at the Beijing Olympics, setting a new world record of 9.69 s.

But could he have gone faster? Many people think so because after the first 80 m of the race, when it was clear that he would win, the Jamaican appeared to stop trying and begun celebrating.

Now, four physicists in Norway have analysed video of the race and concluded that he could have covered the 100 m in as little as 9.55 s (plus or minus 0.04 s) if he had maintained his pre-celebration acceleration.

In a second calculation, the physicists argue that if Bolt had started to flag in the final 20 m — but still matched the acceleration of runner-up Richard Thompson — Bolt still would have finished in 9.61 s (plus or minus 0.04 s).

Cynics have suggested that Bolt held back so he would have a better chance at cracking the world record again, but the world’s fastest man remains silent on exactly why he appears to have stopped trying.