What skills do you use every day in your job?

Obviously, I write: I wouldn’t be a very good science writer if I couldn’t. So communication skills are vital. Recently, for example, Qruise launched a new magnetic-resonance product for which I had to write a press release, create a new webpage and do social-media posts. That meant co-ordinating with lots of different people, finding out the key features to advertise, identifying the claims we wanted to make – and if we have the data to back those claims up. I’m not an expert in quantum computing or magnetic-resonance imagining or even marketing so I have to pick things up fast and then translate technically complex ideas from physics and software into simple messages for a broader audience. Thankfully, my colleagues are always happy to help. Science writing is a difficult task but I think I’m getting better at it.

What do you like best and least about your job?

I love the variety and the fact that I’m doing so many different things all the time. If there’s a day I feel I want something a little bit lighter, I can do some social media or the website, which is more creative. On the other hand, if I feel I could really focus in detail on something then I can write some documentation that is a little bit more technical. I also love the flexibility of remote working, but I do miss going to the office and socialising with my colleagues on a regular basis. You can’t get to know someone as well online, it’s nicer to have time with them in person.

What do you know today, that you wish you knew when you were starting out in your career?

That’s a hard one. It would be easy to say I wish I’d known earlier that I could combine science and writing and make a career out of that. On the other hand, if I’d known that, I might not have done my PhD – and if I’d gone into writing straight after my undergraduate degree, I perhaps wouldn’t be where I am now. My point is, it’s okay not to have a clear plan in life. As children, we’re always asked what we want to be – in my case, my dream from about the age of four was to be a vet. But then I did some work experience in a veterinary practice and I realized I’m really squeamish. It was only when I was 15 or 16 that I discovered I wanted to do physics because I liked it and was good at it. So just follow the things you love. You might end up doing something you never even thought was an option.

The post Ask me anything: Kirsty McGhee – ‘Follow what you love: you might end up doing something you never thought was an option’ appeared first on Physics World.

This episode of the Physics World Weekly podcast explores how quantum computing and artificial intelligence can be combined to help physicists search for rare interactions in data from an upgraded Large Hadron Collider.

My guest is Javier Toledo-Marín, and we spoke at the Perimeter Institute in Waterloo, Canada. As well as having an appointment at Perimeter, Toledo-Marín is also associated with the TRIUMF accelerator centre in Vancouver.

Toledo-Marín and colleagues have recently published a paper called “Conditioned quantum-assisted deep generative surrogate for particle–calorimeter interactions”.

The post Quantum computing and AI join forces for particle physics appeared first on Physics World.

Low-energy electrons escape from some materials via distinct “doorway” states, according to a study done by physicists at Austria’s Vienna Institute of Technology. The team studied graphene-based materials and found that the nature of the doorway states depended on the number of graphene layers in the sample.

Low-energy electron (LEE) emission from solids is used across a range of materials analysis and processing applications including scanning electron microscopy and electron-beam induced deposition. However, the precise physics of the emission process is not well understood.

Electrons are ejected from a material when a beam of electrons is fired at its surface. Some of these incident electrons will impart energy to electrons residing in the material, causing some resident electrons to be emitted from the surface. In the simplest model, the minimum energy needed for this LEE emission is the electron binding energy of the material.

Frog in a box

In this new study, however, researchers have shown that exceeding the binding energy is not enough for LEE emission from graphene-based materials. Not only does the electron need this minimum energy, it must also be in a specific doorway state or it is unlikely to escape. The team compare this phenomenon to the predicament of a frog in a cardboard box with a window. Not only must the frog hop a certain height to escape the box, it must also begin its hop from a position that will result in it travelling through the hole (see figure).

For most materials, the energy spectrum of LEE electrons is featureless. However, it was known that graphite’s spectrum has an “X state” at about 3.3 eV, where emission is enhanced. This state could be related to doorway states.

To search for doorway states, the Vienna team studied LEE emission from graphite as well as from single-layer and bi-layer graphene. Graphene is a sheet of carbon just one atom thick. Sheets can stick together via the relatively weak Van der Waals force to create multilayer graphene – and ultimately graphite, which comprises a large number of layers.

Because electrons are mostly confined within the graphene layers, the electronic states of single-layer, bi-layer and multi-layer graphene are broadly similar. As a result, it was expected that these materials would have similar LEE emission spectra . However, the Vienna team found a surprising difference.

Emission and reflection

The team made their discovery by firing a beam of relatively low energy electrons (173 eV) incident at 60° to the surface of single-layer and bi-layer graphene as well as graphite. The scattered electrons are then detected at the same angle of reflection. Meanwhile, a second detector is pointed normal to the surface to capture any emitted electrons. In quantum mechanics electrons are indistinguishable, so the modifiers scattered and emitted are illustrative, rather than precise.

The team looked for coincident signals in both detectors and plotted their results as a function of energy in 2D “heat maps”. These plots revealed that bi-layer graphene and graphite each had doorway states – but at different energies. However, single-layer graphene did not appear to have any doorway states. By combining experiments with calculations, the team showed that doorway states emerge above a certain number of layers. As a result the researchers showed that graphite’s X state can be attributed in part to a doorway state that appears at about five layers of graphene.

“For the first time, we’ve shown that the shape of the electron spectrum depends not only on the material itself, but crucially on whether and where such resonant doorway states exist,” explains Anna Niggas at the Vienna Institute of Technology.

As well as providing important insights in how the electronic properties of graphene morph into the properties of graphite, the team says that their research could also shed light on the properties of other layered materials.

The research is described in Physical Review Letters.

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