Gravitationally Induced Entanglement between Two Massive Particles is Sufficient Evidence of Quantum Effects in Gravity
Gravitationally Induced Entanglement between Two Massive Particles is Sufficient Evidence of Quantum Effects in Gravity
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DOI：
10.1103/physrevlett.119.240402
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发表时间：
2017-12-13
影响因子：
8.6
通讯作者：
Vedral, V.
中科院分区：
文献类型：
--
作者：
Marletto, C.;Vedral, V.
所有现存的量子引力理论都极难在实践中检验。与电磁场不同，引力场中的量子效应非常小。其根本原因是引力耦合常数比控制光-物质相互作用的精细结构常数小约43个数量级。例如，检测引力子--某些量子引力命题预测的引力场的假设量子--被认为实际上是不可能的。在这里，我们采用了一种完全不同的量子信息论方法来测试量子引力。我们建议在引力场中见证量子特征，通过在两个位置的叠加中探测两个质量。首先，我们证明任何系统（例如，在两个量子系统之间介导纠缠的场）必须是量子的。这个论点是一般性的，不依赖于任何特定的动态。然后，我们提出了一个实验来检测两个质量之间通过引力相互作用产生的纠缠。通过我们的论证，质量间的纠缠度是场量子化的见证。这个实验不需要对引力进行任何量子控制。它也比检测引力子或检测量子引力真空涨落更接近实现。
All existing quantum-gravity proposals are extremely hard to test in practice. Quantum effects in the gravitational field are exceptionally small, unlike those in the electromagnetic field. The fundamental reason is that the gravitational coupling constant is about 43 orders of magnitude smaller than the fine structure constant, which governs light-matter interactions. For example, detecting gravitons-the hypothetical quanta of the gravitational field predicted by certain quantum-gravity proposals-is deemed to be practically impossible. Here we adopt a radically different, quantum-information-theoretic approach to testing quantum gravity. We propose witnessing quantumlike features in the gravitational field, by probing it with two masses each in a superposition of two locations. First, we prove that any system (e.g., a field) mediating entanglement between two quantum systems must be quantum. This argument is general and does not rely on any specific dynamics. Then, we propose an experiment to detect the entanglement generated between two masses via gravitational interaction. By our argument, the degree of entanglement between the masses is a witness of the field quantization. This experiment does not require any quantum control over gravity. It is also closer to realization than detecting gravitons or detecting quantum gravitational vacuum fluctuations.