Category Archives: APS March Meeting 2011

By Hamish Johnston

Physicists are usually a law-abiding bunch, so I was shocked when a group at the APS March Meeting in Dallas, Texas announced that they were going to “break in” to the old Superconducting Super Collider (SSC) site just south of town.

Well, they did manage to get in and they have posted photographs on the web to prove it. There’s something very sad about the photos of the derelict site, especially when contrasted with pictures taken 20 years ago.

Conceived in 1983, the SSC was going to be the next big particle collider with a circumference of 87 km and a maximum collision energy of 40 TeV. That’s as big as Texas compared to the 27 km and 14 TeV of the Large Hadron Collider.

But 10 years later the project was cancelled, leaving a few buildings on the surface as well as tens of kilometres of tunnels deep underground. According to the clandestine team, the tunnels are well below the water table and therefore flooded long ago.

I was tempted to write a blog about the escapade as it played out last week – particularly when the team phoned the press room for directions – but I thought I’d better not tip off the sheriff and his buddies.

When you go down the SSC to have a little fun,
have your ten dollars ready when the policeman comes

They’ll find no Higgs boson,
cause Texas has them SSC blues

Hmm, that’s one for next year’s APS sing-along (to the tune of Deep Elm blues of course)!

By Hamish Johnston

That’s Paul Grant (right) holding one of the high-temperature superconductor demonstration kits that he and his colleagues developed at IBM’s Almaden lab. The idea is that you fill the reservoir with liquid nitrogen and then place a magnet above the superconductor, where it will float.

The kit that Paul is holding was made in 1987 for IBM board members – and if you look at the photograph below you can see “IBM” embossed on the disc of a YBCO superconductor.

But as a 1987 New Scientist article by Grant points out, it’s not that difficult to make your own high-T_c material.

The article describes how Grant’s daughter Heidi (pictured in the clipping held by Grant) and her high-school classmates were able to make their own YBCO superconductor – and then float a magnet over it.

Reading the article I had a strong sense of deja vu. I had just been in a press conference where Kostya Novoselov was asked why graphene research took off like a rocket after he and Andre Geim worked out a way of making stand-alone sheets of the material. His answer was that it was fairly straightforward to make large high-quality samples of graphene and study its many properties.

But that’s where the similarity ends. Although physicists don’t understand everything about graphene, many properties have proven to be exactly as predicted by theory.

The same can’t be said about high-T_c superconductors, which have surprised and confounded physicists for 25 years. That was the subject of a talk today by the University of California’s Bob Dynes. “I will be surprised if there are no more surprises,” said Dynes.

By Susan Curtis at the APS March Meting in Dallas, Texas

It was good to see representatives from the Physical Society of Japan at the APS March Meeting. Keizo Murata of Osaka City University, who is also editor of the Journal of the Physical Society of Japan (JPSJ), wanted us to pass this message on to anyone in the physics community who wishes to make a donation to the relief efforts following the earthquake and tsunami:

“We, the Physical Society of Japan and the JPSJ, deeply appreciate the encouragement we have received from our colleagues all over the world.

“We welcome your donations to the relief and recovery from Japan’s disaster in March 2011. To help this, as well as to avoid any problems with currency exchange, we recommend that you make your donations via authorized organizations in your own country, such as the American Red Cross.

“However, to share your warm sympathy with the worldwide physics community, we would like to recognize your donation. This will be sure to encourage members of the Physical Society of Japan and people around us.

“To achieve this:

1. Send an e-mail to save.japan3.11@jps.or.jp with the subject: “donation Japan disaster” and your name.

2. In the e-mail please note in this order:

• Your name
• Your email address
• Your institution/affiliation
• Your country
• Value of donation (optional)
• The organization that took your donation
• Date of donation
• Any message (optional)
• Permission to use your message with your name on our site (yes/no)

3. If you should make further donations, please send another e-mail to save.japan3.11@jps.or.jp but include “your name (nth time)” in the email.

“Thank you for your kind co-operation,

The Physical Society of Japan
The Journal of the Physical Society of Japan“

Murata also told us that JPSJ is still offering online services as normal, although some publications may be rescheduled.

By Hamish Johnston at the APS March Meeting in Dallas

One of the people in the photo (right) is a robot called Philip K Dick, and the other is David Hanson of Hanson Robotics, which is located just outside of Dallas.

David was talking at the March Meeting about the challenges of making robots that are more lifelike. And not just superficial looks – he’s put a great deal of effort into getting facial expressions right and generally making the robot respond as if it is human.

The problem today is that lifelike robots tend to be creepy (I believe that is a technical term in the industry). This is because getting just a few minor things wrong about how the machine behaves puts it in an uncomfortable place between living and dead – at least, that’s my opinion.

So when will you meet the first robot that is so lifelike that you think it’s human? Hanson thinks it will happen in less than an decade.

I don’t know about you, but that’s creepy!

By Hamish Johnston at the APS March Meeting in Dallas

It’s the second day of the March Meeting and I’ve just done three video interviews, which should start appearing on physicsworld.com in April.

I also managed to make it to a few press conferences, including one on how to make extremely small transistors and antennas.

Above you can see Mark Reed of Yale University who was the first to create a transistor from a single molecule. Reed and colleagues place an organic molecule between two electrodes, which function as the source and drain in a field-effect transistor. The molecule is suspended above a third electrode, which acts as the gate.

You might think that Reed wants to make these tiny resistors to ensure that Moore’s law – the relentless miniaturization of computer chips – continues right down to the molecular level. However, he points out that the biggest threat to Moore’s law today is how to get rid of all the heat generated by a dense clump of tiny transistors. The molecular transistor doesn’t help much with that, and Reed is more interested in studying the fundamental physics of these quantum devices.

Also speaking at the press conference was Niek van Hulst of the Institute of Photonics Science in Barcelona. Van Hulst and colleagues have made tiny antennas that can broadcast and receive visible light.

Such antennas could be put very close to a molecule of interest for example, and capture all the light emitted by the molecule. Conversely it could also be used to direct intense light at just one molecule. Both of these abilities could prove very useful for molecular spectroscopy.

The team has also managed to put a tiny antenna on a scanning tunnelling microscope (STM) tip. Since the antenna is much smaller than the wavelength of the light it emits, such a set-up could be used to image molecules with resolutions much smaller than the wavelength of the light – beating the diffraction limit.

The most beautiful application though, was using an array of antennas coupled to quantum dots, which broadcast the flickering light of quantum noise within the dots.

By Hamish Johnston at the APS March Meeting in Dallas

Will graphene replace silicon as the material of choice for electronics? Many folks have been asking that question since graphene became the latest “wonder material”.

Walter de Heer of the Georgia Institute of Technology answered the question with the above slide.

Just as people and goods are moved by both ships and aeroplanes, De Heer believes that there will be a place for both materials in the future.

While many physicists are trying to develop conventional transistors that use graphene as the semiconductor – essentially replacing silicon – De Heer believes that the wonder material could be used in devices that take advantage of the fact that current is quantized in very narrow ribbons of graphene. This means that quantum interference effects at junctions between ribbons could be used to switch current on and off.

Such transistors would be fundamentally different from conventional devices and immediately made me think of quantum-computing applications. This is possible in principle, according to De Heer, but couldn’t be done at room temperature. This is because the coherence lengths of the devices would be too short – although long enough to achieve switching at junctions.

However, if the junctions were cooled down, the coherence lengths could be long enough for quantum computing. Indeed, De Heer believes that ultimately there will be a place for a material as pure as graphene in quantum computers – perhaps in devices that exploit electron spin.

By Hamish Johnston at the APS March Meeting in Dallas

I spent most of this morning filming 60 second interview spots with top physicists, so I haven’t really got into the swing of things in terms of sessions. Those spots, by the way, should be available on physicsworld.com sometime soon.

I did manage to see a session this morning about silicon qubits. One of the speakers was Jeremy O’Brien of the University of Bristol. Jeremy’s talk was slightly off-topic because he spoke about integrated silicon-based devices that make use of photon as qubits. You can read more about Jeremy’s devices here.

His talk included a nice slide about applications of photon qubits. Quantum metrology is one application that fascinates me. It could be used to do everything from making better optical discs to helping physicists detect gravitational waves.

By Hamish Johnston at the APS March Meeting in Dallas

I’m here in Dallas for the March Meeting of the American Physical Society, which this year will be celebrating the 100th anniversary of the discovery of superconductivity and the 25th anniversary of high-temperature superconductivity.

Eager to get stuck into superconductivity I went to a session on Sunday on industrial physics that, among other things, asked what we could be doing to get more practical use out of superconductors.

And in case you are wondering when physicists will get round to finding a theory for high-T_c superconductivity, Seamus Davis of Cornell University predicted that it will arrive next year – although I think he was being slightly tongue-in-cheek.

On Saturday I did some sightseeing in Fort Worth. After seeing the cowpokes at the stockyard and having some tasty Texas BBQ, we went to the Fort Worth Museum of Science and History.

One physics-related highlight was an exhibit that looked at the geophysics of natural gas exploration. The impressive vehicle above is used to vibrate the ground, sending soundwaves deep into the Earth – a process called vibroseis. These waves reflect off various geological features and are then picked up by an array of microphones back on the surface. After some impressive computer processing, the data are rendered as a 3D image.

Some of the display was focused on the controversial process of hydraulic fracturing or “fracking”. This involves pumping water and a small amount of sand into gas-bearing rock – the pressure of the fluid fractures the rock and the sand props open the cracks. Gas can then escape along the borehole to the surface.

What the exhibit didn’t seem to discuss is the growing controversy surrounding the process. There seemed to be no mention of the concern of some people that some toxic additives to the fracking water could end up seeping into local groundwater, and ultimately into drinking water. That was the subject of a recent documentary film called GasLand.

Other highlights of the museum include a real Sputnik satellite – apparently the Soviets made lots of them, but didn’t get round to sending them into space – and a letter from Albert Einstein to Fort Worth schoolchildren that you can read below.