Einstein, Podolsky and Rosen raised foundational questions about the completeness of quantum mechanics, if certain intuitive logical statements regarding the nature of reality were assumed to be true. These questions are ultimately of significance to the information content of the theory, which is currently the focus of intense research. In this presentation, selected investigations that have made progress in addressing the EPR concerns and that shed light on the nature of quantum states are surveyed. The implications for intuitive classical logic are speculated in the concluding remarks.
Einstein, Podolsky and Rosen raised foundational questions about the completeness of quantum mechanics, if certain intuitive logical statements regarding the nature of reality were assumed to be true. These questions are ultimately of significance to the information content of the theory, which is currently the focus of intense research. In this presentation, selected investigations that have made progress in addressing the EPR concerns and that shed light on the nature of quantum states are surveyed. The implications for intuitive classical logic are speculated in the concluding remarks.
In 1935 Einstein, Podolsky, and Rosen (EPR) published an important paper [17] in which they claimed that the whole formalism of quantum mechanics together with what they called "Reality Criterion" imply that quantum mechanics cannot be complete.That is, there must exist some elements of reality that are not described by quantum mechanics.There must be, they concluded, a more complete description of physical reality behind quantum mechanics.There must be a state, a hidden variable, characterizing the state of affairs in the world in more details than the quantum mechanical state, something that also reflects the missing elements of reality.Under some further but quite plausible assumptions, this conclusion implies that in some spin-correlation experiments the measured quantum mechanical probabilities should satisfy particular inequalities (Bell-type inequalities).The paradox consists in the fact that quantum probabilities do not satisfy these inequalities.And this paradoxical fact has been confirmed by several laboratory experiments in the last three decades.The problem is still open and hotly debated among both physicists and philosophers.It has motivated a wide range of research from the most fundamental quantum mechanical experiments through foundations of probability theory to the theory of stochastic causality as well as the metaphysics of free will.
From a phenomenological and experimental viewpoint, quantum mechanics is remarkably successful in explaining effects and processes in the microscopic world. Recently, however, a growing body of literature has revisited the theory's own formal foundations, specifically addressing issues of self-consistency and completeness. As a major historical example of these foundational challenges, the Einstein-Podolsky-Rosen (EPR) argument famously claimed that the theory is incomplete. While many valid criticisms and refutations of the EPR logic exist, they generally rely on a combination of technical results and conceptual objections to EPR's interpretive assumptions, thus transcending the plain quantum framework itself. Motivated by these trends of examining the theory's structural limits, here we revisit the EPR argument. Focusing on elements essential to the EPR reasoning, we first analyze general quantum correlations for EPR states: (i) the fact that their observables are always associated with non-commuting operators, and (ii) the nature of the correlated information obtained through measurement. From these two points alone, and relying strictly on the core rules of quantum mechanics, we demonstrate how to overturn the alleged EPR incompleteness without invoking any extraneous propositions. Consequently, we show that the standard formalism alone suffices to resolve such type of skepticism regarding the theory's physical reach. This offers, at least in a paradigmatic instance, a powerful indication of a structurally well-founded, self-consistent quantum theory.
Assessment of Einstein's argument Is quantum mechanics complete and local … It was observed in §1.4 that Einstein's method of criticizing the orthodox view of quantum theory was to focus on examples whose special characteristics could be used to show that adherence to the completeness assumption compels one to adopt ‘unnatural theoretical interpretations’. It was a way not of disproving the conventional interpretation by attempting to locate in it some logical flaw, but of pushing it into a corner that in Einstein's view no one would seriously want to inhabit. The paper of Einstein, Podolsky & Rosen (EPR) (1935) is the most famous component of this programme and the purpose of this chapter is to analyse the extent to which the arguments presented in it are compatible with the quantum theory of motion. From contemporaneous correspondence it appears that the EPR paper was written by Podolsky and that Einstein did not consider that the point which was really troubling him had been made explicit (Fine, 1986, Chap. 3). According to Einstein's accounts, EPR had the following purpose: to show that if one believes the wavefunction exhausts all the statements that can be meaningfully asserted about a physical system, then one must also accept that the real physical state of the system depends on what befalls another system with which it has previously interacted, no matter how far apart the two systems may become.
In 1935 Einstein, Podolsky, and Rosen (EPR) published an important paper in which they claimed that the whole formalism of quantum mechanics together with what they called "Reality Criterion" imply that quantum mechanics cannot be complete. That is, there must exist some elements of reality that are not described by quantum mechanics. There must be, they concluded, a more complete description of physical reality behind quantum mechanics. There must be a state, a hidden variable, characterizing the state of affairs in the world in more details than the quantum mechanical state, something that also reflects the missing elements of reality. Under some further but quite plausible assumptions, this conclusion implies that in some spin-correlation experiments the measured quantum mechanical probabilities should satisfy particular inequalities (Bell-type inequalities). The paradox consists in the fact that quantum probabilities do not satisfy these inequalities. And this paradoxical fact has been confirmed by several laboratory experiments in the last three decades. The problem is still open and hotly debated among both physicists and philosophers. It has motivated a wide range of research from the most fundamental quantum mechanical experiments through foundations of probability theory to the theory of stochastic causality as well as the metaphysics of free will.
In the preceding Papers I and II of this series, we have presented a review and upgrade of basic mathematical, physical and chemical methods, and provided a confirmation of the apparent proof of the EPR argument [1] that extended particles within physical media (interior dynamical problems) admit classical counterparts [9], while Einstein’s determinism appears to be progressively verified with the increase of the density of the medium [10]. In this third and final paper of the series, we shown that the EPT argument in general, and Einstein’s determinism in particular, appear to be progressively verified in the structure of mesons, baryon, nuclei, and molecular bonds while being fully verified at the limit of gravitational collapse. We additionally show, apparently for the first time, the validity of the EPR final statement to the effect that the wavefunction [of quantum mechanics] does not provide a complete description of the physical reality” since the covering isowavefunctions of hadronic mechanics provide an otherwise impossible representation of all characteristics of various physical and chemical interior systems existing in nature.
The Einstein–Podolsky–Rosen (EPR) argument was originally posed as a challenge to the completeness of quantum mechanics, rather than its empirical adequacy. While subsequent developments—most notably Bell’s theorem and experimental tests of nonlocal correlations— have constrained classes of hidden-variable theories, they have not resolved the underlying on- tological question raised by EPR: whether the quantum state exhausts physical reality. In this paper, we revisit the EPR criterion of completeness from the perspective of a temporally grounded physical framework, the Temporal Inertia Framework (TIF). We argue that the orig- inal EPR dilemma rests on an implicit assumption that physical reality must be specified on spacelike hypersurfaces, an assumption shared by both EPR and Bohr. By relaxing this assump- tion and allowing physical correlations to arise from shared temporal structure rather than local spatial variables or superluminal influence, one may satisfy the EPR realism criterion without violating relativistic causality or Bell-type constraints. Quantum mechanics is thus interpreted as operationally complete but ontologically incomplete, with quantum indeterminacy emerging from dynamical interactions with a proposed underlying temporal structure.