A master equation for gravitational decoherence: probing the textures of spacetime
A master equation for gravitational decoherence: probing the textures of spacetime
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DOI：
10.1088/0264-9381/30/16/165007
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发表时间：
2013-08-21
影响因子：
3.5
通讯作者：
Hu, B. L.
中科院分区：
文献类型：
--
作者：
Anastopoulos, C.;Hu, B. L.
我们给出了一个主方程的第一性原理推导的量子物质场在线性微扰闵可夫斯基时空的演化，完全基于量子场论和广义相对论。我们不做额外的假设，也不引入额外的成分，就像在替代量子理论中经常做的那样。当量子物质场被投射到单粒子态时，弱引力场中的非相对论性量子粒子的主方程预测了能量基中的退相干，与大多数现有的引力退相干理论相反。我们指出的规范性质的时间和空间reparameterizations在物质引力耦合，并警告说，“内在”退相干或替代量子理论调用随机动力学所产生的时间或空间波动违反了经典广义相对论的基本对称性。有趣的是，我们发现，退相干率依赖于其他参数以外的普朗克尺度，引力退相干的一个重要特征。这类似于量子布朗粒子的退相干速率与其相互作用的环境的温度和光谱密度的依赖关系。当引力作为退散量子物体的环境时，相应的特征就是我们所说的时空的“纹理”。我们指出了引力被表示为背景时空的情况与引力对量子粒子起热力学作用的情况之间的显著差异。这表明了利用引力退相干测量来辨别引力是本质上的基本引力还是突现引力的可能性。
We give a first principles derivation of a master equation for the evolution of a quantum matter field in a linearly perturbed Minkowski spacetime, based solely on quantum field theory and general relativity. We make no additional assumptions nor introduce extra ingredients, as is often done in alternative quantum theories. When the quantum matter field is projected to a one-particle state, the master equation for a non-relativistic quantum particle in a weak gravitational field predicts decoherence in the energy basis, in contrast to most existing theories of gravitational decoherence. We point out the gauge nature of time and space reparameterizations in matter-gravity couplings, and warn that 'intrinsic' decoherence or alternative quantum theories invoking stochastic dynamics arising from temporal or spatial fluctuations violate this fundamental symmetry of classical general relativity. Interestingly we find that the decoherence rate depends on extra parameters other than the Planck scale, an important feature of gravitational decoherence. This is similar to the dependence of the decoherence rate of a quantum Brownian particle to the temperature and spectral density of the environment it interacts with. The corresponding features when gravity acts as an environment in decohering quantum objects are what we call the 'textures' of spacetime. We point out the marked difference between the case when gravity is represented as a background spacetime versus the case when gravity acts like a thermodynamic bath to quantum particles. This points to the possibility of using gravitational decoherence measurements to discern whether gravity is intrinsically elemental or emergent.