Thread by @ExeterOpen

Congrats to Jonas Glatthard for his first published paper! And he did it in style, in #QuantumJournal no less.

"Bending the rules of low-temperature thermometry with periodic driving"
quantum-journal.org/papers/q-2022-…

Wan to get the gist of it? A thread🧵

@UoE_Physics #QuantumTwitter

#QuantumThermometry is HARD. Not just in practice, but even in principle.

As one approaches the absolute zero, the noise-to-signal ratio of temperature estimates diverges.

Hence, it does matter, how fast is this precision loss.

At best, the relative error grows as a power law as T → 0. And the exponent is set by the low-frequency dependence of the density of states of the sample being measured.

quantum-journal.org/papers/q-2019-…

arxiv.org/abs/1712.03088

So, if the precision scaling depends on the sample we are given, there is little that we can do, right?

Here is the thing: We can still modulate the potential that confines the probe we are using to measure the sample. Done right, this can "BEND" the precision scaling law.

We demonstrate this with a Brownian particle in a linear bath. The calculation is painful and long, and FUN! All details are in our generous appendices!

But wait! Is it a good idea to take a cold sample, couple it to a probe, and then keep pumping energy by driving it?

That sounds like a recipe for disaster...

Only it isn't. We show that the steady-state heating of the sample is negligible.

Hope you like the paper!

quantum-journal.org/papers/q-2022-…