The determinism that underlies quantum indeterminism
And the story of John and his dog Bax Morn
John the wood-cutter lives in a hut in the forest with his faithful dog Bax Morn. The hut has two doors, left door and right door, and a call bell on the outside of the hut, in between the two doors.
Every morning John goes out to the woods to cut wood, and comes back in the evening at random times - sometimes a little early when the sun is still up, sometimes a little late, even after dark. But John has no watch nor clock, and in fact has no clue that time can be measured in hours and minutes.
When John rings the bell after returning, Bax Morn opens the left door on some days, and the right door on other days. Which door on which day, is completely random, and John can never predict which door might open on a given day. But he noticed that on the average both doors get opened equally often, over a month say.
Morn's behaviour puzzles and amuses John - such a random dog, he thinks. But he loves Morn, and never questions the dog's apparently random choice of the door. Still, he has this funny feeling after ringing the bell - he thinks of himself as a superposition of John the left and John the right, not knowing which way to go, as if his state has gotten entangled with the two doors. Until one of the doors opens, and his state collapses to John the left or John the right.
But Morn keeps a secret - he is a very smart dog, and the opposite of random. Morn understands time and its measure, and keeps a secret watch, which he never shows to John. For fun, Morn has made a rule. Left door to be opened if it is some minutes past an *even* hour like 4 pm or 6 pm. Right door to be opened after 5 pm or after 7 pm.
Quantum mechanics is like John and Morn. Since John does not know about the secret watch, he concludes that Morn's behaviour is random. The randomness is an apparent consequence of quantum theory being approximate, the approximation being the neglect of the watch.
But the watch is not a hidden variable. It can be detected by using more precise probes than qm uses. If John installs a CCTV camera inside the hut and observes Morn from outside, he will see Morn behaving deterministically, not randomly. [Please allow now for a John who knows the measure of time]. A more complete theory underlying qm includes the watch and the CCTV camera. It is a deterministic theory. The randomness of qm is removed because an extra parameter comes into play now: John's exact time of arrival back home. In qm, this time of arrival is of no consequence to the outcome of the measurement, and that is where the impression of randomness comes from. In the deeper theory, the time of arrival on successive days determines the outcome of the measurement.
Why must there be a deeper theory with a watch and a cctv camera? We explain that in the essay :-)
Tejinder