Here’s the whole crew at the film’s world premiere at AMBER research centre last week 🥰

We cooked up the idea for this experiment over a very fine dinner at our first full @aspects-quantum.bsky.social consortium meeting in Murcia, almost 2.5 years ago. Just shows the importance of good company, free conversation, and some good food 🥘🧁 and wine 🍷 for the scientific and creative process!

Huge thanks to @aspects-quantum.bsky.social partners @naresgroup.bsky.social @quitphysics.info and especially Vivek Wadhia and @mathsmire.bsky.social who really pushed this project from its conception to completion. It’s wonderful to see it all finally come to fruition. ❤️

An interesting implication is that, to make timekeeping efficient in the quantum domain, we should try to avoid measuring the ticks! It’s better to couple the clock directly to whatever system it needs to regulate.

They showed that, for a quantum clock, the entropic cost of recording the ticks dominates the cost of generating them by many orders of magnitude. This not only resolves the paradox of “equilibrium clocks”, but also holds true in the optimal case where the clockwork itself is far from equilibrium

But can a clock—which distinguishes past from future—be truly reversible? Of course not! The resolution is that monitoring equilibrium fluctuations requires a detector that is out of equilibrium, producing entropy. Our friends @naresgroup.bsky.social showed this in a proof-of-principle experiment.

This reflects a general feature of stochastic clocks, as my colleagues and I showed here doi.org/10.1103/rpls...
The optimal observable to estimate time is time-reversal symmetric: it doesn’t care about the direction of time’s arrow, only its length
www.newscientist.com/article/2439...

Even a system in equilibrium fluctuates. If we monitor those fluctuations, we see a time-varying signal that marks the passage of time. This poses a paradox because equilibrium fluctuations produce no entropy. It seems that a clock can operate reversibly! doi.org/10.1103/Phys...

Thank you so much for this! I knew the Nature API was broken but I never appreciated the wider consequences of this (beyond my own frustration that nature won’t even help me cite their content! 🫠)

We find strong system-bath coupling can suppress current fluctuations in a driven quantum system, allowing violation of thermodynamic uncertainty relations! We understand this in terms of the system hybridising with a collective environment mode, which leads to antibunching in the current statistics