Quantum possibilities

Amihud Gilead

This paper differs from any previous view in discussing quantum pure possibilities as individuals, existing independently of any observer or mind. These pure possibilities are also absolutely independent of any metaphysical or logical view that endorses the notion of possible worlds. In my view, the relationship between quantum possibilities and classical physical reality is not between reality as such, as it is in itself, and its phenomena. It is rather between fundamental or primary reality, consisting of quantum pure possibilities, on the one hand, and its actualization in what classical physics has discovered so far, on the other. As individual pure possibilities, quantum entities must be, at least ontologically, distinct and different from one another, regardless of the epistemological standing of quantum physics. Hence, quantum metaphysics is committed to the principle of the identity of indiscernibles. Finally, I analyze the two-slit experiment, interference, and entanglement in the light of my approach.

David Finkelstein

Gordon McCabe, Carfax Publishing

Владик Крейнович, Martine C. Ceberio, Ricardo O. de Alba Alvarez

One of the main reasons why computations - in particular, engineering computations - take long is that, to be on the safe side, models take into account all possible affecting features, most of which turn out to be not really relevant for the corresponding physical problem. From this viewpoint, it is desirable to find out which inputs are relevant. In general, the problem of checking the input's relevancy is itself NP-hard, which means, crudely speaking, that no feasible algorithm can always solve it. Thus, it is desirable to speed up this checking as much as possible. One possible way to speed up such a checking is to use quantum computing, namely, to use the Deutsch-Josza algorithm. However, it is not clear whether a more efficient quantum algorithm is possible for solving this problem. In this paper, we show that the Deutsch-Josza algorithm is, in effect, the only possible way to use quantum computing for checking which inputs are relevant - so no alternative quantum algorithms are possible.

Michael G. Raymer

How does the concept of waves enter quantum theory? In quantum theory, probabilities are determined by considering all the possibilities that may be involved in a certain process. If there are intermediate possibilities involved in a process, quantum theory tells us how to combine...

Christopher R. Monroe, Robert J. Schoelkopf, Mikhail D. Lukin