English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The second law of thermodynamics places a limitation into which states asystem can evolve into. For systems in contact with a heat bath, it can becombined with the law of energy conservation, and it says that a system canonly evolve into another if the free energy goes down. Recently, it's beenshown that there are actually many second laws, and that it is only for largemacroscopic systems that they all become equivalent to the ordinary one. Theseadditional second laws also hold for quantum systems, and are, in fact, oftenmore relevant in this regime. They place a restriction on how the probabilitiesof energy levels can evolve. Here, we consider additional restrictions on howthe coherences between energy levels can evolve. Coherences can only go down,and we provide a set of restrictions which limit the extent to which they canbe maintained. We find that coherences over energy levels must decay at ratesthat are suitably adapted to the transition rates between energy levels. Weshow that the limitations are matched in the case of a single qubit, in whichcase we obtain the full characterization of state-to-state transformations. Forhigher dimensions, we conjecture that more severe constraints exist. We alsointroduce a new class of thermodynamical operations which allow for greatermanipulation of coherences and study its power with respect to a class ofoperations known as thermal operations.

Towards fully quantum second laws of thermodynamics: limitations on the evolution of quantum coherences