  Quantum thermodynamics aims at extending standard thermodynamics and
non-equilibrium statistical physics to systems with sizes well below the
thermodynamic limit. A rapidly evolving research field, which promises to
change our understanding of the foundations of physics, while enabling the
discovery of novel thermodynamic techniques and applications at the nanoscale.
Thermal management has turned into a major obstacle in pushing the limits of
conventional digital computers, and could likely represent a crucial issue also
for quantum computers. The practical realization of quantum computers with
superconducting loops requires working at cryogenic temperatures to eliminate
thermal noise; ion-trap qubits need as well low temperatures to minimize
collisional noise; in both cases, the sub-nanometric sizes also bring about
thermal broadening of the quantum states; and even room-temperature photonic
computers require cryogenic detectors. A number of thermal and thermodynamic
questions therefore take center stage, such as quantum redefinitions of work
and heat, thermalization and randomization of quantum states, the overlap of
quantum and thermal fluctuations, and many other, even including a proper
definition of temperature for the small open systems constantly out of
equilibrium that are the qubits. This overview provides an introductory
perspective on a selection of current trends in quantum thermodynamics and
their impact on quantum computers and quantum computing, with a language
accessible also to postgraduate students and researchers from different fields.
