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Waegell M, Cohen E, Elitzur A, Tollaksen J, Aharonov Y. Quantum reality with negative-mass particles. Proc Natl Acad Sci U S A 2023; 120:e2018437120. [PMID: 37523558 PMCID: PMC10410712 DOI: 10.1073/pnas.2018437120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/02/2023] [Indexed: 08/02/2023] Open
Abstract
Physical interpretations of the time-symmetric formulation of quantum mechanics, due to Aharonov, Bergmann, and Lebowitz are discussed in terms of weak values. The most direct, yet somewhat naive, interpretation uses the time-symmetric formulation to assign eigenvalues to unmeasured observables of a system, which results in logical paradoxes, and no clear physical picture. A top-down ontological model is introduced that treats the weak values of observables as physically real during the time between pre- and post-selection (PPS), which avoids these paradoxes. The generally delocalized rank-1 projectors of a quantum system describe its fundamental ontological elements, and the highest-rank projectors corresponding to individual localized objects describe an emergent particle model, with unusual particles, whose masses and energies may be negative or imaginary. This retrocausal top-down model leads to an intuitive particle-based ontological picture, wherein weak measurements directly probe the properties of these exotic particles, which exist whether or not they are actually measured.
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Affiliation(s)
- Mordecai Waegell
- Institute for Quantum Studies, Chapman University, Orange, CA92866
- Schmid College of Science and Technology, Chapman University, Orange, CA92866
| | - Eliahu Cohen
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan5290002, Israel
- Iyar, The Israeli Institute for Advanced Research, Zichron Ya’akov3095303, Israel
| | - Avshalom Elitzur
- Institute for Quantum Studies, Chapman University, Orange, CA92866
- Iyar, The Israeli Institute for Advanced Research, Zichron Ya’akov3095303, Israel
| | - Jeff Tollaksen
- Institute for Quantum Studies, Chapman University, Orange, CA92866
- Schmid College of Science and Technology, Chapman University, Orange, CA92866
| | - Yakir Aharonov
- Institute for Quantum Studies, Chapman University, Orange, CA92866
- Schmid College of Science and Technology, Chapman University, Orange, CA92866
- Iyar, The Israeli Institute for Advanced Research, Zichron Ya’akov3095303, Israel
- Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978Tel Aviv, Israel
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Cohen E, Cortês M, Elitzur AC, Smolin L. Realism and causality. II. Retrocausality in energetic causal sets. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.102.124028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Cohen E, Carmi A. In Praise of Quantum Uncertainty. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E302. [PMID: 33286076 PMCID: PMC7516759 DOI: 10.3390/e22030302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/21/2020] [Accepted: 03/02/2020] [Indexed: 11/17/2022]
Abstract
Quantum uncertainty has a tremendous explanatory power. Coherent superposition, quantum equations of motion, entanglement, nonlocal correlations, dynamical nonlocality, contextuality, discord, counterfactual protocols, weak measurements, quantization itself, and even preservation of causality can be traced back to quantum uncertainty. We revisit and extend our previous works, as well as some other works of the community, in order to account for the above claims. Special emphasis is given to the connection between uncertainty and nonlocality, two notions which evolved quite independently and may seem distinct but, in fact, are tightly related. Indeterminism, or more precisely, locally consistent indeterminism, should be understood as the enabler of most quantum phenomena (and possibly all of them).
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Affiliation(s)
- Eliahu Cohen
- Faculty of Engineering & the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Avishy Carmi
- Center for Quantum Information Science and Technology & Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beersheba 8410501, Israel;
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Elitzur AC, Cohen E. Some Notes on Counterfactuals in Quantum Mechanics. ENTROPY 2020; 22:e22030266. [PMID: 33286040 PMCID: PMC7516718 DOI: 10.3390/e22030266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 02/23/2020] [Accepted: 02/23/2020] [Indexed: 11/16/2022]
Abstract
Counterfactuals, i.e., events that could have occurred but eventually did not, play a unique role in quantum mechanics in that they exert causal effects despite their non-occurrence. They are therefore vital for a better understanding of quantum mechanics (QM) and possibly the universe as a whole. In earlier works, we have studied counterfactuals both conceptually and experimentally. A fruitful framework termed quantum oblivion has emerged, referring to situations where one particle seems to "forget" its interaction with other particles despite the latter being visibly affected. This framework proved to have significant explanatory power, which we now extend to tackle additional riddles. The time-symmetric causality employed by the Two State-Vector Formalism (TSVF) reveals a subtle realm ruled by "weak values," already demonstrated by numerous experiments. They offer a realistic, simple and intuitively appealing explanation to the unique role of quantum non-events, as well as to the foundations of QM. In this spirit, we performed a weak value analysis of quantum oblivion and suggest some new avenues for further research.
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Affiliation(s)
- Avshalom C. Elitzur
- Institute for Quantum Studies, Chapman University, Orange, CA 92866, USA;
- Iyar, The Israeli Institute for Advanced Research, POB 651, Zichron Ya’akov 3095303, Israel
| | - Eliahu Cohen
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
- Correspondence: ; Tel.: +972-373-84268
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The Weak Reality That Makes Quantum Phenomena More Natural: Novel Insights and Experiments. ENTROPY 2018; 20:e20110854. [PMID: 33266578 PMCID: PMC7512416 DOI: 10.3390/e20110854] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/02/2018] [Accepted: 11/03/2018] [Indexed: 11/26/2022]
Abstract
While quantum reality can be probed through measurements, the Two-State Vector Formalism (TSVF) reveals a subtler reality prevailing between measurements. Under special pre- and post-selections, odd physical values emerge. This unusual picture calls for a deeper study. Instead of the common, wave-based picture of quantum mechanics, we suggest a new, particle-based perspective: Each particle possesses a definite location throughout its evolution, while some of its physical variables (characterized by deterministic operators, some of which obey nonlocal equations of motion) are carried by “mirage particles” accounting for its unique behavior. Within the time interval between pre- and post-selection, the particle gives rise to a horde of such mirage particles, of which some can be negative. What appears to be “no-particle”, known to give rise to interaction-free measurement, is in fact a self-canceling pair of positive and negative mirage particles, which can be momentarily split and cancel out again. Feasible experiments can give empirical evidence for these fleeting phenomena. In this respect, the Heisenberg ontology is shown to be conceptually advantageous compared to the Schrödinger picture. We review several recent advances, discuss their foundational significance and point out possible directions for future research.
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Aharonov Y, Cohen E, Elitzur AC, Smolin L. Interaction-Free Effects Between Distant Atoms. FOUNDATIONS OF PHYSICS 2017; 48:1-16. [PMID: 31997829 PMCID: PMC6956877 DOI: 10.1007/s10701-017-0127-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/29/2017] [Indexed: 06/10/2023]
Abstract
A Gedanken experiment is presented where an excited and a ground-state atom are positioned such that, within the former's half-life time, they exchange a photon with 50% probability. A measurement of their energy state will therefore indicate in 50% of the cases that no photon was exchanged. Yet other measurements would reveal that, by the mere possibility of exchange, the two atoms have become entangled. Consequently, the "no exchange" result, apparently precluding entanglement, is non-locally established between the atoms by this very entanglement. This quantum-mechanical version of the ancient Liar Paradox can be realized with already existing transmission schemes, with the addition of Bell's theorem applied to the no-exchange cases. Under appropriate probabilities, the initially-excited atom, still excited, can be entangled with additional atoms time and again, or alternatively, exert multipartite nonlocal correlations in an interaction free manner. When densely repeated several times, this result also gives rise to the Quantum Zeno effect, again exerted between distant atoms without photon exchange. We discuss these experiments as variants of interaction-free-measurement, now generalized for both spatial and temporal uncertainties. We next employ weak measurements for elucidating the paradox. Interpretational issues are discussed in the conclusion, and a resolution is offered within the Two-State Vector Formalism and its new Heisenberg framework.
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Affiliation(s)
- Yakir Aharonov
- School of Physics and Astronomy, Tel Aviv University, 6997801 Tel-Aviv, Israel
- Schmid College of Science, Chapman University, Orange, CA 92866 USA
- Iyar, The Israeli Institute for Advanced Research, POB 651, 3095303 Zichron Ya’akov, Israel
| | - Eliahu Cohen
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL UK
- Iyar, The Israeli Institute for Advanced Research, POB 651, 3095303 Zichron Ya’akov, Israel
| | - Avshalom C. Elitzur
- Schmid College of Science, Chapman University, Orange, CA 92866 USA
- Iyar, The Israeli Institute for Advanced Research, POB 651, 3095303 Zichron Ya’akov, Israel
| | - Lee Smolin
- Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2J 2Y5 Canada
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Aharonov Y, Cohen E, Landau A, Elitzur AC. The Case of the Disappearing (and Re-Appearing) Particle. Sci Rep 2017; 7:531. [PMID: 28373649 PMCID: PMC5427996 DOI: 10.1038/s41598-017-00274-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/15/2017] [Indexed: 11/09/2022] Open
Abstract
A novel prediction is derived by the Two-State-Vector-Formalism (TSVF) for a particle superposed over three boxes. Under appropriate pre- and post-selections, and with tunneling enabled between two of the boxes, it is possible to derive not only one, but three predictions for three different times within the intermediate interval. These predictions are moreover contradictory. The particle (when looked for using a projective measurement) seems to disappear from the first box where it would have been previously found with certainty, appearing instead within the third box, to which no tunneling is possible, and later re-appearing within the second. It turns out that local measurement (i.e. opening one of the boxes) fails to indicate the particle's presence, but subtler measurements performed on the two boxes together reveal the particle's nonlocal modular momentum spatially separated from its mass. Another advance of this setting is that, unlike other predictions of the TSVF that rely on weak and/or counterfactual measurements, the present one uses actual projective measurements. This outcome is then corroborated by adding weak measurements and the Aharonov-Bohm effect. The results strengthen the recently suggested time-symmetric Heisenberg ontology based on nonlocal deterministic operators. They can be also tested using the newly developed quantum router.
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Affiliation(s)
- Yakir Aharonov
- School of Physics and Astronomy, Tel Aviv University, Tel-Aviv, 6997801, Israel.,Schmid College of Science, Chapman University, Orange, CA, 92866, USA.,Iyar, The Israeli Institute for Advanced Research, POB 651, Zichron, Ya'akov, 3095303, Israel
| | - Eliahu Cohen
- Iyar, The Israeli Institute for Advanced Research, POB 651, Zichron, Ya'akov, 3095303, Israel. .,H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK.
| | - Ariel Landau
- School of Physics and Astronomy, Tel Aviv University, Tel-Aviv, 6997801, Israel
| | - Avshalom C Elitzur
- Iyar, The Israeli Institute for Advanced Research, POB 651, Zichron, Ya'akov, 3095303, Israel
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D'Ariano GM, Khrennikov A. Preface of the special issue quantum foundations: information approach. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2015.0244. [PMID: 27091161 PMCID: PMC4843640 DOI: 10.1098/rsta.2015.0244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/15/2016] [Indexed: 06/05/2023]
Abstract
This special issue is based on the contributions of a group of top experts in quantum foundations and quantum information and probability. It enlightens a number of interpretational, mathematical and experimental problems of quantum theory.
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Affiliation(s)
| | - Andrei Khrennikov
- International Center for Mathematical Modeling in Physics and Cognitive Sciences Linnaeus University, Växjö-Kalmar, Sweden
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