• ABSTRACT – BELL TEST ON PHOTONS

The experimental setup of IQOQI will generate pairs of light particles (photons), which are entangled in their polarization (i.e., the direction along which the electro-magnetic field of the photons oscillates). The photons of a pair are then separated and guided to individual measurement stations. There, the polarization is measured along two different directions, whereby the random numbers provided by the participants of the Big Bell Test dictate the actual setting. In this way, we can analyze the polarization correlations between photon pairs and see if the results violate the Bell inequality.

• FACTS
  • Within the blink of an eye, our setup can produce up to 5 million entangled photon pairs.In our lab, the random numbers of the participants are converted into the respective measurement settings within only 0.0000001 seconds (i.e., 100 nano-seconds).
  • The measurement settings are implemented using so-called “Pockels Cells”. Thereby, a voltage of roughly 1500 V has to be applied across specific crystals the entangled photons have to pass.
  • A similar kind of setup was used in an experiment between the Canary Islands of La Palma and Tenerife, in which we conducted a Bell test with entangled photons that were separated by 144km, still the world-record distance today.

• QUOTE

“We would like to thank all Bellsters for their random numbers! But still, quantum mechanics won the race!“

1. Name of lab:

IQOQI Vienna Quantum Communication Lab

2. Team:

Bo Liu, Johannes Handsteiner, Dominik Rauch, Rupert Ursin, Anton Zeilinger and Thomas Scheidl (PI).

3. Organization:

IQOQI-Institute of Quantum Optics and Quantum Information, ViennaAustrian Academy of Sciences

4. City:

Vienna

5. GPS coordinates of the experiment:

48°13″16.8″N 16°21″23.4″E

6. Name of experiment:

Violation of a Bell Inequality using Entangled Photons and Human Random Numbers

7. Target Bell inequality and experimental result obtained:

In our experiments, we tested the CHSH bell inequality (|S|≤2 for local realism) using the polarization entangled photons. We used mixed random sources for the BBT server. In the experiment 1, we used human random numbers (HRN) mixed with quantum random numbers (QRN) and in the experiment 2, we used HRN mixed with random bits from database (DB). In data processing, we then could separate our results with respect to the source of implemented random numbers. We implemented all random bits in real time in the experiments.In experiment 1, we obtained a value for S of 2.639±0.008, which corresponds to a violation of the inequality by more than 80 standard deviations.In experiment 2, we obtained a value for ???? of 2.643±0.006, which corresponds to a violation of the inequality by more than 107 standard deviations.

8. What did the experiment test?

The existence of correlations which cannot be explained by local hidden variable models under the assumptions of locality, fair sampling and no-signalling.

9. Physical system used:

Photons.

10. Degree of freedom measured:

Polarization.

11. Rate of bits consumed & total number of bits:

In experiment 1:HRN rate is 1612.88bps, in total 322576 bits; QRN rate is 2727.68bps, in total 545536 bits.In experiment 2:HRN rate is 910.21bps, in total 191144 bits; DB rate is 3404.49bps, in total 714943 bits.

12. What was the use of the bits of the Bellsters?

The bits were used to control the Pockel Cells to switch the polarization of the incoming photons.

13. How long did the experiment take?

Experiment 1: 200 seconds, 2016.11.30 14:51:50;Experiment 2: 210 seconds, 2016.11.30 14:56:52.

14. Did you use all the bits in real time?

Yes.

15. Distance between Alice and Bob

Source to Alice: 3mSource to Bob: 3m