Abstract In this second part of the series of comments for foundation of quantum mechanics,we concentrate ourselves in the EPR paradox.The recent development of this field is critically surveyed and our comments or suggestions for further investigations are added.We show that quantum mechanics can be rewritten realistically by using the so-called hidden variables.The local realistic theory is the common feature in most theory of natural science.Quantum mechanics also has this common feature and is not an exceptional theory in science.|量子力学の基礎についてのコメントと題するシリーズの第2部では、EPRパラドックスに重点をおく。この分野の最近の発展が批判的に概観され、さらなる研究へのコメントと示唆が付加されている。量子力学はいわゆるかくされた変数を用いて実在論的に書き直すことが可能である。この局所実在論は多くの自然科学の理論で共通にみられることである。量子力学もまたこの共通点をもち、科学における例外的な理論ではない。
Abstract In this second part of the series of comments for foundation of quantum mechanics,we concentrate ourselves in the EPR paradox.The recent development of this field is critically surveyed and our comments or suggestions for further investigations are added.We show that quantum mechanics can be rewritten realistically by using the so-called hidden variables.The local realistic theory is the common feature in most theory of natural science.Quantum mechanics also has this common feature and is not an exceptional theory in science.|量子力学の基礎についてのコメントと題するシリーズの第2部では、EPRパラドックスに重点をおく。この分野の最近の発展が批判的に概観され、さらなる研究へのコメントと示唆が付加されている。量子力学はいわゆるかくされた変数を用いて実在論的に書き直すことが可能である。この局所実在論は多くの自然科学の理論で共通にみられることである。量子力学もまたこの共通点をもち、科学における例外的な理論ではない。
The foundation of quantum mechanics is now wide-spread area of researches in physics. The most important topics of it is the problem of the EPR paradox. In this first part of our articles we treat mainly the EPR paradox. The critical survey of the history of quantum mechanics is tried in the ordinary way. Then the typical formulation of the EPR problem and the Bell's inequality is presented.Lastly we try to discuss the future style of the foundation of interpretation of quantum mechanics.|量子力学の基礎は現在物理学における広いひろがりをもつ研究領域となっている。その最も重要なトピックスはEPRパラドックスの問題である。我々の論文の第1部分である今回は主としてEPRパラドックスをとりあつかっている。量子力学の歴史の批判的概観が通常の方法で試みられている。ついで,EPR問題とベルの不等式の典型的な定式化がなされている。最後に量子力学の解釈の基礎の将来の様式が論じられる。
Quantum mechanics is an immensely successful theory, occupying a unique position in the history of science. It has solved mysteries ranging from macroscopic superconductivity to the microscopic theory of elementary particles and has provided deep insights into the nature of vacuum on the one hand and the description of the nucleon on the other. Whole new fields such as quantum optics and quantum electronics owe their very existence to this body of knowledge. However, despite the stunning successes of quantum mechanics, there is no general agreement on the conceptual foundations and interpretation of the subject. The theory provides unambiguous information about the outcome of a measurement of a physical object. However, many feel that it does not provide a satisfactory answer to the nature of the “reality” we should attribute to the physical objects between the acts of measurement. The conceptual difficulty comes about because the wave function |ψ〉 is usually given by a coherent superposition of various distinguishable experimental outcomes. If we denote the collection of states that represent the possible outcomes of an experiment by |ψ j 〉, then |ψ〉 = ∑ j c j |ψ j 〉 where c j = 〈ψ j |ψ〉. The probability of the outcome |ψ j 〉 is P j =|c j | 2 . In the process of measurement, the so called collapse of the wave function takes place and a single, definite state |ψ i 〉 of the physical object is chosen. The difficulty comes about in the interpretation of the mechanism by which this definite state is chosen from amongst all the possible outcomes.
Abstract Einstein's severe critique of quantum mechanics took its ultimate form in the so‐called Einstein Podolsky Rosen (EPR) paradox. The latter remained a subject of mere dispute, until a remarkable progress was initiated in 1964 by Bell who showed that quantum mechanical correlations specific for an EPR type experiment cannot be reproduced in any local hidden—variables theory. Afterwards, realistic versions of EPR experiments have been conceived and, in fact, carried out. The objective of the present paper is to give a review of this recent exciting development, both theoretical and experimental, which reveals one of the most striking features of quantum theory, the “quantum interconnectedness of distant systems”.
Despite its remarkable success in describing microscopic phenomena, quantum mechanics continues to pose unresolved foundational questions concerning measurement, nonlocality, wavefunction collapse, and the nature of physical reality. These issues were highlighted by the EPR paradox1-2, in which Einstein and his co-authors examined the measurement of entangled particles in space-like separation. Quantum mechanics predicts that measuring one particle’s observable instantaneously determines the state of the other, seemingly violating special relativity’s prohibition of faster-than-light influences and suggesting an incomplete description of physical reality. However, Bell’s theorem3-5, along with the Bell-Kochen-Specker theorem6-10 and subsequent experiments, has largely ruled out local hidden variable theories. In this work, I apply the quantum decoherence framework11-13, pioneered by Zeh, Zurek, Joos and Leggett et al. to analyze an EPR-like system using system-environment interactions as a measurement model. I demonstrate that measurement on one entangled particle does not instantaneously collapse the system's wavefunction. Instead, the local wavefunctions of the measured particle and its environment evolve dynamically, while the remote particle’s wavefunction remains unchanged. Environment-induced decoherence selects pointer states and rapidly suppresses quantum correlations through local interactions, giving rise to the appearance of wavefunction collapse. These findings suggest that quantum mechanics can be reconciled with local realism if the wavefunction is treated as an ontic entity, offering a potential path toward a locally realistic quantum theory in alignment with Einstein’s vision.
We argue that the so-called entangled states in quantum theory are not something exceptional, deserving a special attention in our efforts to understand conceptual foundations of quantum world. They appear by constructing the basis states of a compound system via the basis states of entering subsystems and describe it as a wholeness. While a system is considered as a wholeness, the individual members, forming the entangled state, have no physical meaning. In consequence, there is no physical ground for Einstein, Podolsky and Rosen (EPR) correlations arising in a process of decaying the system, being in the entangled state, into its constituent parts. The same regards to Bell’s introduced non-locality of quantum world. 1
Despite its remarkable success in describing microscopic phenomena, quantum mechanics continues to pose unresolved foundational questions concerning measurement, nonlocality, wavefunction collapse, and the nature of physical reality. These issues were highlighted by the EPR paradox. Quantum mechanics predicts that measuring one particle’s observable instantaneously determines the state of the other, seemingly violating special relativity’s prohibition of faster-than-light influences and suggesting an incomplete description of physical reality. However, Bell’s theorem has largely ruled out local hidden variable theories. In this paper, I critically examine the assumptions in deriving Bell’s theorem and demonstrate that the theorem does not apply strictly to quantum mechanics. By assuming measurement is always accompanied by uncontrollable environment interactions, I show that quantum theory can be local and realism with decoherence in EPR-like measurement. Specifically, I apply the quantum decoherence framework, pioneered by Zeh, Zurek and Leggett to analyze an EPR-like system using system-environment interactions as a measurement model. The results illustrate that measurement on one entangled particle does not instantaneously collapse the system's wavefunction. Instead, the local wavefunctions of the measured particle and its environment evolve dynamically, while the remote particle’s wavefunction remains unchanged. Environment-induced decoherence selects pointer states and rapidly suppresses quantum correlations through strictly local interactions, giving rise to the appearance of wavefunction collapse. These findings challenge the conventional interpretation of Bell’s theorem and suggest that quantum mechanics fundamentally respects locality and realism if the wavefunction is treated as an ontic entity. This work offers a potential path toward a locally realistic quantum theory in alignment with Einstein’s vision. It not only strengthens the conceptual foundations of quantum mechanics, but also carries tremendous implications for quantum information processing and computing.