Figure 2: Quantum thermodynamics as the combination of asymmetry and thermodynamic purity.
From: Description of quantum coherence in thermodynamic processes requires constraints beyond free energy
The blue oval represents the convex set of all quantum states. To any state ρ, we can associate a ‘thermal cone’ (in red), the convex set of states thermally accessible from it. Any state ρ contributes in terms of thermodynamic purity p, which corresponds to the deviation of 
from the thermal state γ—as measured by {Fα}—and asymmetry a, which corresponds to the deviation of ρ from the manifold of time-symmetric states (the grey region)—as measured by {Aα}.
