Entanglement between the Future and the Past in the Quantum Vacuum

[limarodessa]

Hello all ! Help me please. I can not understand – which particles are entangled in this case

http://prl.aps.org/abstract/PRL/v106/i11/e110404

We note that massless fields within the future and past light cone may be quantized as independent systems. The vacuum is shown to be a nonseparable state of these systems, exactly mirroring the known entanglement between the spacelike separated Rindler wedges. This leads to a notion of timelike entanglement. We describe an inertial detector which exhibits a thermal response to the vacuum when switched on at t=0, due to this property. The feasibility of detecting this effect is discussed, with natural experimental parameters appearing at the scale of 100 GHz.

Full text here http://arxiv.org/PS_cache/arxiv/pdf/1003/1003.0720v1.pdf

 

[Demystifier]

In this case, it is easier to think of it as if the entangled objects are not particles, but the field degrees of freedom.