  Quantum thermodynamic quantities, normally formulated with the assumption of
weak system-bath coupling (SBC), can often be contested in physical
circumstances with strong SBC. This work presents an alternative treatment that
enables us to use standard concepts based on weak SBC to tackle with quantum
thermodynamics with strong SBC. Specifically, via a physics-motivated mapping
between strong and weak SBC, we show that it is possible to identify
thermodynamic quantities with arbitrary SBC, including work and heat that shed
light on the first law of thermodynamics with strong SBC. Quantum fluctuation
theorems, such as the Tasaki-Crooks relation and the Jarzynski equality are
also shown to be extendable to strong SBC cases. Our theoretical results are
further illustrated with a working example.
