  The quantum realm involves curious correlations between distant events. A well-known example is David Bohm's (1951) version of the famous thought experiment that Einstein, Podolsky and Rosen proposed in 1935 (henceforth, the EPR/B experiment). Pairs of particles are emitted from a source in the so-called spin singlet state and rush in opposite directions (see Fig. 1 below). When the particles are widely separated from each other, they each encounter a measuring apparatus that can be set to measure their spin components along various directions. Although the measurement events are distant from each other, so that no slower-than-light or light signal can travel between them, the measurement outcomes are curiously  correlated.[1]  That is, while the outcome of each of the distant spin measurements seems to be a matter of pure chance, they are correlated with each other: The joint probability of the distant outcomes is different from the product of their single probabilities. For example, the probability that each of the particles will spin clockwise about the z-axis in a z-spin measurement (i.e., a measurement of the spin component along the z direction) appears to be ½. Yet, the outcomes of such measurements are perfectly anti-correlated: If the left-hand-side (L-) particle happens to spin clockwise (anti-clockwise) about the z-axis, the right-hand-side (R-) particle will spin anti-clockwise (clockwise) about that axis. And this is true even if the measurements are made simultaneously.