Consistent histories and the Bohm approach.

AbstractIn a recent paper Griffiths claims that the consistent histories interpretation of quantum mechanicsgives rise to results that contradict those obtained from the Bohm interpretation. This is in spiteof the fact that both claim to provide a realist interpretation of the formalism without the need toadd any new mathematical content and both always produce exactly the same probability predictionsof the outcome of experiments. In contrasting the differences Griffiths argues that the consistenthistories interpretation provides a more physically reasonable account of quantum phenomena. Weexamine this claim and show that the consistent histories approach is not without its difficulties. 1 Introduction It is well known that realist interpretations of the quantum formalism are known to be notoriously difficultto sustain and it is only natural that the two competing approaches, the consistent history interpretation(CH) [1] [2] and the Bohm interpretation(BI)[3][4], shouldbe carefullycomparedand contrasted. Griffiths[5] is right to explore how the two approaches apply to interferometers of the type shown in figure 1.Although the predictions of experimental outcomes expressed in terms of probabilities are identical,Griffiths argues that, nevertheless, the two approaches actually give very different accounts of how aparticle is supposed to pass through such an interferometer. After a detailed analysis of experiments basedon figure 1, he concludes that the CH approach gives a behaviour that is ‘physically acceptable’, whereasthe Bohm trajectories behave in a way that appears counter-intuitive and therefore ‘unacceptable’. Thisbehaviour has even been called ‘surrealistic’ by some authors