W e live in a quantum world - something physicists have considered with amazement for more than seventy years. But we now realize that quantum physics is more than a radical departure from classical physics. It also offers many new possibilities for information processing.
All experiments are in remarkable agreement with quantum theory.
First, thanks to the long coherence time of the pump laser, the time at which the two photons are created is affected by quantum uncertainty, but the two photons are created at exactly the same time. Figure 1 . The results of the measurements are retransmitted to Geneva, revealing the nonlocal quantum correlations. There, energy and time measurements are performed. The arm length difference of both interferometers is much larger than the coherence length of the individual photons, hence, no single photon interferences occur.