Here, you can see an animation of the excitation travelling around a ring of 50 sites (y-axis = occupation probability, x-axis = where).

What started as informal discussions on the Danube beach in Vienna during QTD2023 has been published at last. Trying to come up with an experimentally feasible quantum clock we came across a rich model – the ring clock – that overturned a common wisdom in the community. doi.org/10.1038/s415...

... and here are the pendula themselves

... and here the pendulum center of mass

Haha, it seems I can not upload Gifs properly 😅 Let's hope this works: here is the 'coolest' animation ...

a) Ignorance about microscopic degrees of freedom and b) a past hypothesis saying you start in a low entropy state. Combined, the assumptions lead to entropy increase over time. For the pendulum, a) is given by the compass needle only seeing the 'center of mass' and b) by the initial configuration.

If we now imagine that in the top right of the setup, you have a compass needle pointing towards the center of mass of the collection of pendulum masses (say the masses are magnetized), the compass needle will have a 'quite random' behavior, as the animations show, but it stays somewhat centered.

Think of a collection of mathematical pendula, all swinging with a different frequency. The time-evolution of this system in the idealized setting without friction is fully reversible.

Now that our recent work on the emergence of a 2nd law of thermodynamics in isolated quantum systems has been published, I thought it may be a good opportunity to share some animations outlining the intuition for the principle behind it.

doi.org/10.1103/PRXQ...

See thread below 👇

Bonjour Grenoble! Nice to see the beauty of the alps in Austria stretches all the way to France 🏔️
Here to visit the QEI conf. and curious to learn how others think about thermo of quantum computation. Tomorrow I'll talk about work (arXiv:2402.00111) we did in Vienna. Come by if you are around.