论文标题
在有限温度初始初始化的封闭量子系统的绝热定理
Adiabatic theorem for closed quantum systems initialized at finite temperature
论文作者
论文摘要
每当系统状态保持接近其时间依赖性的哈密顿量的瞬时特征态时，驱动量子系统的演变就被据称是绝热的。著名的量子绝热定理可确保可以任意准确地维持这种纯净的状态绝热性，只要选择了足够小的驾驶速度即可。在这里，我们将量子绝热性的概念扩展到最初在有限温度下制备的封闭量子系统。在这种情况下，绝热性意味着系统的（混合）状态在哈密顿式的瞬时特征态在基础上保持接近准gibbs状态。我们证明了有限温度绝热性的足够条件。值得注意的是，这意味着有限的温度绝热性可以比纯状态绝热性更强，尤其是在多体系统中。我们提供了一个多体系统的示例，在热力学极限中，保持有限的温度绝热性，而纯状态的绝热性则分解。
The evolution of a driven quantum system is said to be adiabatic whenever the state of the system stays close to an instantaneous eigenstate of its time-dependent Hamiltonian. The celebrated quantum adiabatic theorem ensures that such pure state adiabaticity can be maintained with arbitrary accuracy, provided one chooses a small enough driving rate. Here, we extend the notion of quantum adiabaticity to closed quantum systems initially prepared at finite temperature. In this case adiabaticity implies that the (mixed) state of the system stays close to a quasi-Gibbs state diagonal in the basis of the instantaneous eigenstates of the Hamiltonian. We prove a sufficient condition for the finite temperature adiabaticity. Remarkably, it implies that the finite temperature adiabaticity can be more robust than the pure state adiabaticity, particularly in many-body systems. We present an example of a many-body system where, in the thermodynamic limit, the finite temperature adiabaticity is maintained, while the pure state adiabaticity breaks down.
