Hideyuki Sakai: "Einstein was wrong?" EPR paradox and a test of Bell inequality by proton pairs
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Europe/Budapest
Tanácsterem
Tanácsterem
Description
We have carried out the spin-correlation measurement of two protons
in a spin singlet state aiming to test the EPR paradox presented by Einstein, Podolsky
and Rosen in 1935. The EPR proposed a thought experiment in which they showed according
to quantum mechanics that the result of a measurement of an entangled quantum system
performed on earth, for example, can instantaneously influence the result of a measurement
performed on the far distant Galaxy regardless of the distance. This of course contradicts
with the theory of special relativity by Einstein, no information can be transmitted faster
than the speed of light. Therefore EPR argued that quantum mechanics must be incomplete.
In 1964, Bell found an extremely important inequality which is the embodiment
of the EPR arguments. The prediction of the spin-correlation by the Bell's inequality
is different from that by the quantum mechanics so that we can test experimentally
which assertion is right by the measurement.
After a short introduction of the EPR paradox, I try to explain how we realized
experimentally an almost pure spin singlet state of two protons and how we measured
the spin polarizations of two protons. Essential difference from photon pair experiments will be touched.
