2017/03/31 by Shang-Yung Wang
Chemistry · Computer Science · Engineering · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Chemistry #Physics #Quantum #Quantum Information and Cryptography #Quantum mechanics #Quantum thermodynamics #Second law of thermodynamics #Statistical physics #Thermal Radiation and Cooling Technologies #Thermodynamics #Work (physics) #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1088/1751-8121/aa996b
published as J. Phys. A 51 (2018) 035305 · 17 pages, 3 figures, to appear in J. Phys. A
arxiv created 2017/11/09 · openalex publication_date 2017/11/09 · arxiv updated 2017/12/18 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/06
Abstract We revisit the problem of work extraction from a system in contact with a heat bath to a work storage system, and the reverse problem of state formation from a thermal system state in single-shot quantum thermodynamics. A physically intuitive and mathematically simple approach using only elementary majorization theory and matrix analysis is developed, and a graphical interpretation of the maximum extractable work, minimum work cost of formation, and corresponding single-shot free energies is presented. This approach provides a bridge between two previous methods based respectively on the concept of thermomajorization and a comparison of subspace dimensions. In addition, a conceptual inconsistency with regard to general work extraction involving transitions between multiple energy levels of the work storage system is clarified and resolved. It is shown that an additional contribution to the maximum extractable work in those general cases should be interpreted not as work extracted from the system, but as heat transferred from the heat bath. Indeed, the additional contribution is an artifact of a work storage system (essentially a suspended ‘weight’ that can be raised or lowered) that does not truly distinguish work from heat. The result calls into question the common concept that a work storage system in quantum thermodynamics is simply the quantum version of a suspended weight in classical thermodynamics.