337 research outputs found
The Einstein-Podolsky-Rosen Argument and the Bell Inequalities
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
From No-signaling to Spontaneous Localization Theories
GianCarlo Ghirardi passed away on June 1st, 201. He would have turned 83 on October 28, 2018. He was without any doubt one of the most prominent theoretical physicists working on the foundation and the philosophy of quantum mechanics. In this paper I review some of his achievements and underline how his research influenced the philosophy of physics community
The Einstein-Podolsky-Rosen Argument and the Bell Inequalities
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
Quantum realism is consistent with quantum facts
Despite the unparalleled accuracy of quantum-theoretical predictions across
an enormous range of phenomena, the theory's foundations are still in doubt.
The theory deviates radically from classical physics, predicts counterintuitive
phenomena, and seems inconsistent. The biggest stumbling block is measurement,
where the Schrodinger equation's unitary evolution seems inconsistent with
collapse. These doubts have inspired a variety of proposed interpretations and
alterations of the theory. Most interpretations posit the theory represents
only observed appearances rather than reality. The realistic interpretations,
on the other hand, posit entities such as other universes, hidden variables,
artificial collapse mechanisms, or human minds, that are not found in the
standard mathematical formulation. Surprisingly, little attention has been paid
to the possibility that the standard theory is both realistic and correct as it
stands. This paper examines several controversial issues, namely quantization,
field particle duality, quantum randomness, superposition, entanglement,
non-locality, and measurement, to argue that standard quantum physics,
realistically interpreted, is consistent with all of them.Comment: 25 pages, 5 figures, 1 tabl
Quantum Entanglement vs Non-Locality
In this brief paper, we argue about the relationship between quantum
entanglement and non-locality
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