After discussing in the first five sections the meaning and the difficulties of the principle of relativity we present a new sel of spacetime transformations between inertial systems (“inertial” transformations), based on three assumptions: (1) The two-way velocity of light is c in all inertial systems and in all directions; (2) Time dilation effects take place with the usual relativistic factor; (3) Clocks are synchronized in the way chosen by nature itself, e.g., in the Sagnac effect. We show that our (...) new transformation laws can explain the available experimental evidence in spite of the implied noninvariance of the one-way velocity of light. (shrink)

Fundamental experiments on the dual nature of atomic entities (photons, electrons, neutrons, etc.) can be interpreted in terms of “empty” waves not carrying energy and momentum. Similar points of view were advanced in famous papers by Einstein, de Broglie, Bohr, and Born. Recent proposals could lead to experimental tests of this idea, using low intensity photon beams, thanks to modern experimental apparatuses.

After some considerations about the equivalence of the objective local theories to the deterministic theories of Bell's type, a simple and systematic way to deduce inequalities from Einstein locality is introduced: All the inequalities deduced by Bell and by other authors, as well as several new ones, are so obtained. Some theorems are proven which show how striking the difference is at small angles between a correlation function satisfying Einstein locality and the quantum mechanical one. Experiments at small angles involve (...) weaker additional assumptions than those used up to now in experimental research on Bell's inequality. (shrink)

The experimental evidence for electromagnetic signals propagating with superluminal group velocity is recalled. Transformations of space and time depending on a synchronization parameter, e1, indicate the existence of a privileged inertial system. The Lorentz transformations are obtained for a particular e1≠0. No standard experiment on relativity depends on e1, but if accelerations are considered only e1=0 remains possible. The causal paradox generated by superluminal signals (SLS) in the theory of relativity does not exist in the theory with e1=0. The irrelevance (...) of SLS for the Einstein, Podolsky and Rosen paradox is pointed out. (shrink)

TABLE OF CONTENTS: Introduction; de Broglie's paradox.; Quantum theory of distant particles; The EPR paradox; Einstein locality and Bell's inequality; Recent research on Bell's inequality; General consequences of Einstein locality; Nonloeality and relativity; Time-symmetric theories; The Bohm-Aharonov hypothesis; Experiments on Einstein locality; Reduction of the wave packet; Measurements, reality and consciousness; Conclusions.

We show that a method exists for deducing from Einstein locality all the possible inequalities for linear combinations of correlation functions. This allows us to show also that there is a complete observational equivalence of deterministic local theories and probabilistic local theories.

A generalized reality criterion which attributes physical properties to statistical ensembles is used in order to deduce an inequality which is violated by quantum mechanics in realistic conditions. This new form of the Einstein-Podolsky-Rosen paradox is developed exclusively from the reality criterion and from separability without any use of the previously introduced restrictive assumptions about the probabilistic scheme.

We formulate a model of EPR experiments by including variables determining whether a photon will be detected or not. The resulting deterministic model satisfies Bell's original inequality even though it can agree exactly with the quantum mechanical predictions for the performed experiments. It violates variations of the inequality used in the interpretation of the experiments and deduced with the help of additional assumptions.

Popper's idea of propensities constituting the physical background of predictable probabilities is reviewed and developed by introducing a suitable formalism compatible with standard probability calculus and with its frequency interpretation. Quantum statistical ensembles described as pure cases (“eigenstates”) are shown to be necessarily not homogeneous if propensities are actually at work in nature. An extension of the theory to EPR experiments with local propensities leads to a new and more general proof of Bell's theorem. No joint probabilities for incompatible observables (...) need to be introduced. (shrink)

By following the analysis of De Caro and Garuccio [Phys. Rev. A 54, 174 (1996)], we show that the factorable state vector produced with a beam-splitter set on the paths of parametric down-converted photons violates some new inequalities that we deduce from local realism. These inequalities are more stringent than those used up to now in the discussion of such phenomena.

Probabilistic local realism for two correlated systems as formulated by Clauser and Horne in 1974 is shown to be necessarily based on a perfect specification of the state and on an individual definition of probability. All known realistic formulations of probability calculus are instead defined in terms of relative frequencies, and perfect specifications of states are impossible. We reformulate probabilistic local realism by using the relative frequency definition only and show that the Einstein, Podolsky, and Rosen paradox still obtains.

First it is proved that, in a deterministic theory, Malus' law requires that, if a photon is successively transmitted by two polarizers with appropriately chosen settings, the first transmission influences a hidden variable (co-) determining the second one. We derive from this that in an ideal EPR experiment (giving the result predicted by quantum mechanics for two correlated photons transmitted by two polarizers with suitably chosen settings) there has to be a nonlocal influence from the “first” transmission interaction to the (...) second. Subsequently we argue that we can abandon determinism as an assumption so that the locality hypothesis is in any case untenable if the predictions of quantum mechanics are all correct. (shrink)

The results of a previous paper for the properties of the correlation functionP(θ) at small angles following from Einstein locality are extended to the general case whereP(0)≠−1. Experimental investigations are suggested to check the validity of some theorems on the behavior of the correlation functionP(θ) which are deduced directly from Einstein locality.

The traditional approach to light amplification is shown to be based on the idea that photons of the incoming beam act as independent particles. If atomic stimulation is instead attributed to the action of the wave, a different photon distribution is obtained in the final state. The new distribution turns out to be Poissonian, in agreement with some experimental evidence. The expected rate of coincidences for an empty-wave amplification experiment is calculated, and found up to 30% higher than obtained from (...) the traditional approach. (shrink)

"Die vorliegende Fassung des Textes wurde anhand des englischen Originalmanuskriptes von Franco Selleri unter Mitarbeit von Roman U. Sexl erstellt."--T.p. verso.

Con E = m c2 la teoria della relatività ha generato una conquista conoscitiva di enorme importanza. Tuttavia la stessa teoria ha svuotato di significato oggettivo questa scoperta affermando che i punti di vista divergenti dei diversi osservatori inerziali sul valore numerico di Esono equivalenti. Una recente critica della nozione relativistica del tempo ha spostato il baricentro concettuale della fisica dello spazio e del tempo verso l'esistenza di un sistema privilegiato, restituendo alla formula di Einstein tutta la sua importanza.

Old and recent ideas concerning the nature of time are reviewed, starting from Mach's refusal of Newton's absolute time. Many experiments show that the slowing down of moving clocks is a real phenomenon. Such must then also be the so-called “twin paradox,” which owes its name to its evident incompatibility with the philosophy of relativism (not to be confused with the theory of relativity). The Lorentz reformulation of special relativity started by postulating physical effects of the ether, but accepted Einstein's (...) clock synchronization. Only because of this Lorentz could not understand the advantages of an easily deducible different theory. As stressed by Popper, one of the main problems of the usual approach is the introduction of a superdeterministic universe. Recent results obtained by the author show that a theory is possible, based on relative time but on absolute simultaneity, in which the conceptual difficulties of relativity are avoided. (shrink)

On the occasion of his ninetieth birthday, Karl Popper's lifelong pursuit of answers in several areas of scientific and philosophical thinking is briefly traced, mainly with reference to excerpts from his own writings.