Humans of Physics V: Guillaume Berthet

This is the fifth installment of Humans of Physics, a series focusing in the researchers more than in the research, for once.

The first time I entered in the room where the cold atom experiment was, I couldn’t express what I felt… Wires everywhere, optical fibers sending lasers all over the room, a metallic vacuum chamber hidden by a huge amount of copper wire, optical fibers and water cooled magnetic coils… A big mess. My supervisor asked me to have a look inside the vacuum chamber through a thick glass. After five minutes trying to find the right angle I finally saw it. A red bubble surrounded by darkness. This was a billion atoms trapped in the vacuum… I was really impressed.

My first day as a PhD student was a bit stressful. My first task was to switch on the experiment. There were so many things to think about and so many parts of the experiment that I didn’t understand ! I slowly completed my task thanks to the wise advices of the other PhD student. I remember him saying : “coffee break ?!” when the experiment was finally working. I really enjoyed this moment because we took time to know each other and to talk about physics. At lunch time, we ate together with students, post-docs and researchers from the group. In France, lunch time is at least one hour long (sacred time) and it is the perfect moment to exchange about our difficulties and how we solve problems encountered in the lab. Talking with them helped me to feel better and more confident.

I spent the rest of the day working in the lab with my supervisor. I remember him speaking fast, talking about Feshbach resonances, Thomas-Fermi regime and other names I never heard about… This was exhausting but also very interesting. My day ended and I went to bed, knackered, with the feeling that I still had so many things to learn.

Three years later, I have built a new experiment. I know it well enough so I can draw it from memory. I know what Feshbach resonances are, and even more important: I can share my knowledge with younger students during lunch times and coffee breaks. Experimental research is a long process that requires passion and patience and if it weren’t for my colleagues I wouldn’t have such a good memory of my three years as a PhD student. I had the opportunity to work with French, German, Danish, Italian, Greek, Chinese and even Indian students and researchers always pleased to share their skills and knowledge. This was a rich human and scientific experience. Older PhD students and supervisors practice is necessary to handle the experimental setup. Discussions with colleagues from other groups is essential to have a good understanding of data analysis. Showing our results on conference is the best way to ensure we find the best way to share our research.

It is definitely not a job that you can do on your own…

This is the fourth installment of Humans of Physics, a project which searches to show how we scientists are just like everyone. Dispelling some stereotypes is probably a good idea, from time to time. 

For me, the cliché is true. Every morning I get woken up by the birds. It’s actually a chime but it still feels good and I congratulate myself for having found it on my phone every morning. It’s seven, I try to roll between my sheets as long as possible without falling back to sleep. Usually the fool-proof way to do that is to put on a podcast of yet more grueling news. I’ll start with the short German one. Then if I need more time, the English one. At some point around twenty past seven I will crawl out of bed, do my morning stretches, get dressed and go downstairs to get breakfast. I’ll balance the warm bowl of porridge and the tea upstairs to my room. While clutching the cup I will try to keep myself motivated for long enough to write a little to do list in my diary. I will make sure my workout, watering my plants and going outside is on there as well as all the work stuff. Sometimes I will drift off at that point, either too excited to focus or too bored to be bothered. It’s usually videos on Youtube on why polar bear numbers are rising in some places in the Arctic or pictures of London on Pinterest in anticipation for my master’s that I will start in October.

Focus has never been something that I found in my bedroom but since the pandemic hit in March, I was forced to make it work, for better or worse. I try to work in two-hour chunks, sometimes I take extended breaks in between my pomodoros. I will start to sing Christmas carols on the top of my lungs to lose the building sense of frustration when nothing is working, or I will go out to cuddle the family dog when I am too excited. What helps me stick to my desk is the pot of tea I will cook after my breakfast tea. I always stay where the tea is. My work is concerned with the comparison of ocean temperatures and currents in the North Atlantic in hope to find out more about how ocean currents change over time. I try to crunch numbers produced by climate models, I put them into plots and maps of the North Atlantic which I will spend forever to make as intuitive (read: pretty) as possible. I look up how to make a certain type of plot in online forums, I look for bugs in my code.

By the end of each two hour slot I will be severely exhausted and by the second or third slot I will definitely need a break. My preferred way of getting out of my head at the moment is a run through the fields near our house. This usually also means more time for podcasts: self-help ones, those about the latest science or long interviews are all great for running. The evenings are now a strictly work-free regime. I will read, watch Netflix or have two-and-a-half hour discussions with friends over facetime. By eleven I’ll be back in bed, still devoted to science in my sleep by giving the free computing power of my phone to medical research that uses artificial intelligence.

Guillaume Berthet loves to get his hands dirty in a lab. As an experimental physicists and PhD student in Paris he cooled atoms close to the lowest temperature in the universe.

What is Mass? Part I

This is the second installment of our “What is…?” series. 

During these months of quarantine, a lot of us have probably thought once or twice that we have been putting on some quarantine-weight. And while that is true (or not, for you, athletic reader) what is actually happening, is that you body is acquiring mass. A somewhat trivial difference, you may say, as weight is just the force inflicted by gravity on to some body. And it strikes me as a funny thing that in our everyday physics, everything comes intuitively to us, force, speed, acceleration, rotation stuff. Everything -but mass. It feels intuitive, but the more you think about it, the more you will end up asking yourself… What is mass?

Continue reading “What is Mass? Part I”