Posts by: Hamish Johnston

What do strange metals and black holes have in common?

Subir Sachdev

Subir Sachdev.

By Hamish Johnston in Waterloo, Canada

Harvard’s Subir Sachdev has just taken the audience here at the Convergence conference on a delightful romp through the phase diagram of the cuprate high-temperature superconductors. What I found most interesting was not the superconducting phase, but rather Sachdev’s description of the “strange metal” phase.

This phase occurs when the cuprate copper-oxide layer is highly doped with holes and has perplexed physicists for some time – hence its strange moniker. It has no quasiparticles and lots of low-energy excitations so there is no easy way to describe the collective behaviour of the electrons.

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Maria Spiropulu talks about multiple Higgs beyond the Standard Model

 

By Hamish Johnston in Waterloo, Canada

Caltech’s Maria Spiropulu has a great party trick. She can demonstrate the bizarre rotational property of a spin ½ particle using a full glass of water and a contortion of her arm without spilling a drop. This was just one of the many highlights of her talk about the future of experimental particle physics that she gave yesterday at the Convergence meeting here at the Perimeter Institute.

While Spiropulu doesn’t talk about spin in the above video, she does explain why she is looking forward to analysing data from the 13 TeV run of the Large Hadron Collider, where she is part of the CMS collaboration. So, what could Spiropulu and colleagues find when they dig into the vast amounts of data that CMS is currently producing? It just could be four more types of Higgs particle. To find out more watch the video.

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Busting dust deep underground in SNOLAB

SNOLAB's Nigel Smith (left), Ian Lawson (centre) and Chris Jillings

Squeaky clean: SNOLAB’s Nigel Smith (left), Ian Lawson (centre) and Chris Jillings.

By Hamish Johnston at the CAP Congress in Edmonton, Alberta

I’m a bit of a DIY enthusiast and one thing that I know about drilling into a masonry wall is that you should hold a vacuum-cleaner hose to the hole or you will end up with dust all over the wall and the floor below. Believe it or not, that is exactly what workers at SNOLAB in Canada do in order to keep background levels of radiation from affecting their dark-matter and neutrino detectors.

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The physics of Alzheimer’s disease

Jennifer Tang and Maikel Rheinstadter

Jennifer Tang and Maikel Rheinstadter.

By Hamish Johnston at the CAP Congress in Edmonton, Alberta

One promising route to understanding the causes of Alzheimer’s disease (AD) –  and hopefully finding a cure – is the study of how and why proteins in the brain sometimes form neurotoxic plaques. These plaques are disc-like structures that are about 50 µm in diameter and made from polypeptides. Their presence in the grey matter of the brain is strongly associated with AD and some other neurological conditions, but why they form and why they cause dementia are both not understood.

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Muzzling scientists leads to mistrust of government says physicist MP

Canadian MP Ted Hsu believes in free speech for government scientists

Canadian MP Ted Hsu believes in free speech for government scientists.

By Hamish Johnston at the CAP Congress in Edmonton, Canada

Yesterday I caught up with Ted Hsu, who is member of the Canadian parliament for Kingston and the Islands – and a former physicist. Hsu is a member of the Liberal party, which means he sits on the opposition benches. There he has been an outspoken critic of the current Conservative government over its apparent “muzzling” of scientists on the federal payroll. He believes that when governments seek to silence their experts it leads to more public mistrust of government.

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Debating warp bubbles and quark novae over beer and samosas

Photograph of Miguel Alcubierre lecturing in Edmonton

Time traveller: Miguel Alcubierre works the crowd in Edmonton.

By Hamish Johnston at the CAP Congress in Edmonton, Canada

The first day of the Canadian Association of Physicists (CAP) Congress at the University of Edmonton closed yesterday on the theme of time travel. Surely that is science fiction, you are thinking? But Miguel Alcubierre of the National Autonomous University of Mexico (UNAM) wasn’t joking when he delivered the Herzberg Memorial Lecture yesterday evening (although he did giggle a lot during his talk, which was very endearing). The session was called “Faster than the speed of light” and it was a fascinating romp through some of the more bizarre implications of Einstein’s general theory of relativity (GR) – which is 100 years old this year.

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Lament for ‘the reactor that can do everything’

Photograph of inside the NRU

Inside the NRU. (Courtesy: Atomic Energy of Canada)

By Hamish Johnston at the CAP Congress in Edmonton

In 1957 Atomic Energy of Canada built “a reactor that can do everything” at Chalk River, Ontario. Dubbed the National Reactor Universal – or NRU – that facility will shut down for good in 2018 and Canada’s neutron-science community is now pondering its future.

In the short term, physicists will have to travel abroad to use neutron sources, such as those at Oak Ridge in the US and Grenoble in France. The challenge during this 10–15 year period will be to keep the research community together and make sure that vital skills and expertise built up over decades at the NRU will be retained. In the longer term, there are calls for Canada to build a new neutron facility, but it is by no means clear whether that will happen.

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‘Physics across Canada’ tour kicks off in Edmonton

 

By Hamish Johnston

Greetings from Edmonton on the western edge of the Canadian prairies, where I am starting my “Physics across Canada” tour. The nation’s physicists are gathering here for the annual Canadian Association of Physicists Congress at the University of Alberta.

The congress opens today with a session that promises to be out of this world. Exoplanet expert Sara Seager of the Massachusetts Institute of Technology is talking about the search for habitable worlds beyond our blue planet. I am really keen to learn more about the latest techniques for studying the atmospheres of exoplanets and I plan to record an interview about that very subject later this week.

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The landscapes of CERN, 20 years of BECs and the truth about toilet swirl

 

By Hamish Johnston

Everyone knows that water in a draining sink or toilet swirls in opposite directions on opposite sides of the equator…or does it? For the answer, watch the instructions in the above video and then go to “The truth about toilet swirl”.

Physicists at CERN are a lucky bunch. As well as having the world’s most energetic collider at their disposal, they are also surrounded by the natural beauty of the Alps and the Jura mountains. However, I’ve always felt that the CERN site itself and the flat farmland that overlays the Large Hadron Collider (LHC) are rather dull.

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Atomic time was born 60 years ago today

 

By Hamish Johnston

“The death of the astronomical second and the birth of atomic time” is how the British physicist Louis Essen described 3 June 1955, when the world’s first practical atomic clock ticked for the first time.

The place was Teddington on the outskirts of London, which is home to the National Physical Laboratory (NPL). Essen’s clock was based on a beam of caesium atoms and was monitored by microwave technology inspired by his wartime work on radar. The clock was more than a metre long and nicknamed the “Flying Bedstead” by engineers at the BBC, who used it as an input for their radio time signal. The clock made atomic time available worldwide for the first time 60 years ago. Then, in 1967, the second was redefined as an SI unit based on an atomic transition in caesium, thereby ending the ancient practice of defining time though astronomical observations.

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