Back to Classical Reality

Heinrich Päs

F. J. Duarte

Is there a quantum reality which is distinct from a ‘classical reality’? Or is there only one reality determined by physical measurements? The observation by Dalitz and Duarte – ‘Already in 1948, observations agreed with quantum mechanics, not with local realism’ – appears to suggest a departure from classical reality. However, going back to the inescapable truth that Nature describes herself via the experiment , then such divergence between quantum and classical realities is not all that transparent since what made the quote above possible is the nonlocality of the photon . And the nonlocality of the photon is a measurable physical phenomenon. This observation suggests that quantum reality is grander and includes, as a subset, ‘classical reality.’

Chandrasekhar Roychoudhuri

We already know that in the purely technological frontier, photonics is going to play a leading role during this century riding on the shoulders of electronics-, bio- and nano-technologies. This talk will underscore that the fundamentals of photonics as has already been developed by classical optics, specifically, the Superposition Principle (SP) will play a profound role in bringing REALITY in physics while opening up many new paths to innovations by opening up new understandings behind SPSP. becomes manifest only when the detectors and the detectees are within each others range of interacting forces and can exchange energy allowed by the quantum restrictions to manifest the measurable transformations undergone by them. The deeper recognition of this fundamentally “local” SP will guide us overcome many conceptual bottlenecks, appreciate deeper realities hidden behind the current quantum formulation, remove the unnecessary non-causal interpretations of quantum mechanics, bridge classical and quantum optics and bring back conceptual freedoms for many new photonics innovations. One of the many specific examples is that the apparent spectrometric resolution limit δvδt <1 is not a fundamental principle of nature. I will show mathematical and experimental work to establish this assertion.

Bernard d’Espagnat

Bernard d’Espagnat

A. Casher, Benni Reznik

Measurements are ordinarily described with respect to absolute ``Newtonian'' time. In reality, however, the switching-on of the measuring device at the instance of the measurement requires a timing device. Hence the classical time t must be replaced by a suitable quantum time variable \ensuremath{\tau} of a physical clock. The main issue raised in this paper is that while doing so, we can no longer neglect the back reaction due to the measurement on the clock. For a von Neumann measurement model, this back reaction yields a bound on the accuracy of the measurement. When this bound is violated the result of a measurement is generally not an eigenvalue of the observable, and furthermore, the state of the system after the measurement is generally not a pure state. We argue that as a consequence, a subclass of observables in a closed system cannot be realized by a von Neumann--like measurement.