A note on the time evolution of a density operator interpolating between pure and mixed states

• Published in: The European physical journal. B, Condensed matter physics Vol. 93; no. 10
• Main Authors: Figueiredo, E. G., Malbouisson, J. M. C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2020; Springer; Springer Nature B.V
• Subjects: Complex Systems; Condensed Matter Physics; Density; Evolution; Fluid- and Aerodynamics; Physics; Physics and Astronomy; Regular Article; Solid State Physics; Time dependence; Solid State and Materials
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2020-10152-0

In a recent paper [C.J.S. Ferreira, T.M. Silva, B. Baseia, Eur. Phys. J. B
92
, 257 (2019)], the authors discuss the time evolution of statistical properties of a density operator that interpolates between pure and mixed states, assuming that the time evolution of the system is carried out by a specific time dependence of the coefficients that weight the admixing of the states. Here, we show that this assumption does not correspond exactly to any physical time evolution of the initial state of the system, being only a specific approximation. We present the exact evolution of the system in contact with a dissipative reservoir at zero temperature and discuss the time evolution of interpolations of pure and mixed states.
Graphical abstract