Mari Andrea, De Palma Giacomo, Giovannetti Vittorio
NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
INFN, Edificio C, Largo Bruno Pontecorvo, 3, 56127 Pisa PI, Italy.
Sci Rep. 2016 Mar 9;6:22777. doi: 10.1038/srep22777.
We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations and for the possibility of entangling a particle with quantum gravitational radiation.
我们考虑一个思想实验，其中在量子叠加态中制备一个宏观上有质量或带电的粒子，以及远处测试粒子的相关动力学，这显然允许超光速通信。我们基于以下基本原理给出了这个悖论的解决方案：任何区分相干叠加态和非相干统计混合态的局部实验，必然需要一个与系统质量（或电荷）成正比的最短时间。对于带电粒子，我们考虑了此类实验的两个例子，并表明它们都与先前的限制相一致。在第一个例子中，测量需要加速电荷，这会与发射的光子发生纠缠。在第二个例子中，该限制可归因于电磁场的量子真空涨落。另一方面，当应用于有质量的粒子时，我们的结果为引力真空涨落的存在以及粒子与量子引力辐射纠缠的可能性提供了间接证据。
