Thermodynamics and Information at the nanoscale

This talk will cover recent advances in the field of Quantum Thermodynamics, an emerging field that aims to uncover the thermodynamic laws at the nanoscale [1]. I will begin with explaining a (classical) nanoscale thermodynamic experiment with optically trapped nanospheres that undergo Brownian motion in air [2]. These spheres experience a non-equilibrium situation due to heating from the trapping laser. By using a suitable two-bath model to analyse the data, one can infer the surface temperature of the trapped spheres and also observe temperature gradients across the nanospheres. I will then move on to theoretical results concerning thermodynamic work in the quantum regime, i.e. can a different amount of work be extracted from a quantum system than from a classical system? To solve this we set up a quantum thermodynamic process that removes quantum information in analogy to Landauer’s erasure of classical information. The thermodynamic analysis of such a process uncovers that work can be extracted from quantum coherences in addition to the work that can be extracted from classical non-equilibrium states [3]. Finally, I will report on a thermodynamic uncertainty relation that limits the accuracy of measuring the temperature and energy of a thermal quantum system [4]. Corrections to the standard uncertainty relation arise here because, unlike in standard thermodynamics, a small system’s interaction with its environment is not negligible. The emerging relation unites thermodynamic and quantum uncertainties for the first time.

[1] Quantum thermodynamics, S. Vinjanampathy, J. Anders, Contemporary Physics 57, 545 (2016).
[2] Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere, J. Millen, T. Deesuwan, P. Barker, J. Anders, Nature Nanotechnology 9, 425 (2014).
[3] Coherence and measurement in quantum thermodynamics, P. Kammerlander, J. Anders, Scientific Reports 6, 22174 (2016).
[4] Energy-temperature uncertainty relation in quantum thermodynamics, H. Miller, J. Anders, Nature Communications 9:2203 (2018).