Editing Bell test (section)

=== Christensen et al. (2013): overcoming the detection loophole for photons ===
The Christensen et al. (2013)<ref name = "christensen">{{cite journal |last=Christensen |first=B.G. |author2=K. T. McCusker |author3=J. Altepeter |author4=B. Calkins |author5=T. Gerrits |author6=A. Lita |author7=A. Miller |author8=L. K. Shalm |author9=Y. Zhang |author10=S. W. Nam |author11=N. Brunner |author12=C. C. W. Lim | author13 = N. Gisin |author14-link=Paul Kwiat| author14 = P. G. Kwiat | date= 26 September 2013|title=Detection-Loophole-Free Test of Quantum Nonlocality, and Applications |journal=Physical Review Letters |volume=111 |issue=7448 |pages=130406 |doi=10.1103/PhysRevLett.111.130406 |arxiv= 1306.5772 |bibcode = 2013PhRvL.111m0406C | pmid=24116754|s2cid=14278916 }}</ref> experiment is similar to that of Giustina et al.<ref name="giustina" /> Giustina et al. did just four long runs with constant measurement settings (one for each of the four pairs of settings). The experiment was not pulsed so that formation of "pairs" from the two records of measurement results (Alice and Bob) had to be done after the experiment which in fact exposes the experiment to the coincidence loophole. This led to a reanalysis of the experimental data in a way which removed the coincidence loophole, and fortunately the new analysis still showed a violation of the appropriate CHSH or CH inequality.<ref name="larsson">{{cite journal |last=Larsson |first= Jan-Åke |author2=Marissa Giustina |author3= Johannes Kofler |author4=Bernhard Wittmann |author5=Rupert Ursin |author6=Sven Ramelow |date=16 September 2014 |title=Bell violation with entangled photons, free of the coincidence-time loophole |journal=Physical Review A |volume=90 |issue=7448 |pages=032107 |doi=10.1103/PhysRevA.90.032107 |arxiv=1309.0712 |bibcode=2014PhRvA..90c2107L|s2cid= 40197990 }}</ref> On the other hand, the Christensen et al. experiment was pulsed and measurement settings were frequently reset in a random way, though only once every 1000 particle pairs, not every time.<ref name="christensen" />