Thermodynamics, quantum mechanics, and information theory are three independent areas of science developed in different times in the history. Historically, the intersections of these three areas proved to be highly fruitful in terms of uncovering new knowledge, including quantum thermodynamics (e.g. quantum heat engine, untra-cold atomic gases), information thermodynamics (e.g. Maxwell demon,algorithmic cooling), and quantum information theory.
In this talk, I plan to share my personal (re)discovery of some results in the interdisciplinary problems in the intersection of these three areas. I would first present a two-line proof of the second law of thermodynamics using the machinery of quantum information theory---a result certainly known by many experts but not as popularized as it should be. Then, I would explain how the problem of Maxwell’s demon can be naturally resolved from this point of view. (Again, the problem of Maxwell’s demon has puzzled physicists for more than 100 years; although it has been more or less understood from the point of view of information-entropy approach pioneered by people including Szilard, Landauer, and Bennett, the resolution is not as well-spread as it should be). Next, I will connect the Maxwell-demon problem with the idea of algorithmic cooling, and if I have time, I would also explain my recently published result on quantum algorithmic cooling.