We analyze the phase space trajectories generated under coupling between a dynamic system and a thermal reservoir which generates a fluctuating as well as dissipative force field. We argue that the phase space trajectory of particles associated with intermediate equilibrium states under heat transfer possess a symmetric form, while the corresponding trajectory is asymmetric in energy transfer as work. The new perspective can help in developing a closed form expression of heat and work at

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... opic dimensions with a few degrees of freedom. We also present a novel mathematical model of thermal reservoir as a dynamic system described using a transfer function comprising of a set of zeros. It addresses the theoretical weaknesses of current models of a thermal reservoir comprising of a collection of harmonic oscillators.