We consider a collision between a moving particle and a fixed system, each having internal degrees of freedom. We identify the regime where the motion of the particle acts as a work source for the joint internal system, leading to energy changes which preserve the entropy. This regime arises when the particle has high kinetic energy and its quantum state of motion is broad in momentum and narrow in space, whether pure or mixed. In this case, the scattering map ruling the dynamics of the internal degrees of freedom becomes unitary and equivalent to that of a time-dependent interaction between the internal degrees of freedom of the colliding systems. It follows that the kinetic energy lost by the particle during the autonomous quantum collision coincides with the work performed by the time-dependent interaction. Recently, collisions with particles were shown to act as heat sources under suitable conditions; here we show that they can also act as work sources. This opens interesting perspectives for quantum thermodynamics formulations within scattering theory.

中文翻译：

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量子散射作为工作源

我们考虑运动粒子和固定系统之间的碰撞，每个系统都具有内部自由度。我们确定了粒子运动作为联合内部系统的工作源的机制，导致能量变化保持熵。当粒子具有高动能并且其运动的量子态在动量上宽而在空间上窄（无论是纯粒子还是混合粒子）时，就会出现这种情况。在这种情况下，支配内部自由度动力学的散射图变得单一并且等效于碰撞系统的内部自由度之间的时间相关相互作用。由此可见，粒子在自主量子碰撞过程中损失的动能与时间相关相互作用所做的功是一致的。最近，在合适的条件下，与粒子的碰撞被证明可以作为热源；在这里，我们展示了它们也可以作为工作来源。这为散射理论中的量子热力学公式打开了有趣的视角。