Infrared divergences and quantum coherence
Infrared divergences and quantum coherence
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红外发散和量子相干性
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
S. Zell
中科院分区：
文献类型：
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作者：
César Gómez;Raoul Letschka;S. Zell
在量子电动力学或微扰引力等远程力的理论中，只有包含发射软辐射的速率才不会消失。与探测器分辨率无关，只有在对该辐射的红外分量进行积分后才能获得有限的可观测值。这种积分可能会导致量子相干性的一些损失。然而，在本文中，我们认为它通常不应导致完全退相干。基于幺正性，我们提出了一种定义 IR 有限密度矩阵的非消失非对角部分的方法。对于这个红外有限密度矩阵，我们估计了量子相干性损失（即其纯度）对散射运动学的依赖性。
In theories with long-range forces like QED or perturbative gravity, only rates that include emitted soft radiation are non-vanishing. Independently of detector resolution, finite observables can only be obtained after integrating over the IR-component of this radiation. This integration can lead to some loss of quantum coherence. In this note, however, we argue that it should in general not lead to full decoherence. Based on unitarity, we suggest a way to define non-vanishing off-diagonal pieces of the IR-finite density matrix. For this IR-finite density matrix, we estimate the dependence of the loss of quantum coherence, i.e. of its purity, on the scattering kinematics.