On the Conservation of Information and the Second Law of Thermodynamics

How can these fundamental laws be consistent?

The conservation of quantum information, quantified in term of von Neumann entropy, is a fundamental consequence of the linearity and unitarity of quantum mechanics. As the terms information and entropy are often used interchangeably in several branches of sciences, this may sound very strange to anyone familiar with the second law of thermodynamics, which says that entropy generally increases with time. How can these claims be…