论文标题
Feynman繁殖器和不可逆性的迹象
Sign of the Feynman Propagator and Irreversibility
论文作者
论文摘要
对于标量电动力学的相互作用的Feynman繁殖器$δ_{f，int}（x，y）$，我们表明标志属性，$ \ perperatorname {re}iΔ__{f，int} \ geq 0 $，呈现时间进化的可持续性。相比之下，$ \ operatorname {im}iδ_{f，int} $是不确定的。当我们切换到弱耦合近似下的减少动力学时，除非我们对控制时间演变的Kraus操作员对Kraus操作员施加严重限制，否则通常会丢失$ \ operatatOrname {re}iΔ__{f，int} $的正半段标志。通过另一个近似值，旋转波近似，我们可以通过在某些条件下将测试函数限制为指数来恢复符号。
For the interacting Feynman propagator $ Δ_{F,int}(x,y) $ of scalar electrodynamics, we show that the sign property, $ \operatorname{Re} iΔ_{F,int} \geq 0 $, hinges on the reversibility of time evolution. In contrast, $ \operatorname{Im} iΔ_{F,int} $ is indeterminate. When we switch to reduced dynamics under the weak coupling approximation, the positive semidefinite sign of $ \operatorname{Re} iΔ_{F,int} $ is generally lost, unless we impose severe restrictions on the Kraus operators that govern time evolution. With another approximation, the rotating wave approximation, we may recover the sign by restricting the test functions to exponentials under certain conditions.
