Past of a quantum particle revisited

Berthold-Georg Englert, Kelvin Horia, Jibo Dai, Yink Loong Len, and Hui Khoon Ng

Phys. Rev. A 96, 022126 – Published 21 August 2017

Abstract

We analyze Vaidman's three-path interferometer with weak path marking [L. Vaidman, Phys. Rev. A 87, 052104 (2013)] and find that common sense yields correct statements about the particle's path through the interferometer. This disagrees with the original claim that the particles have discontinuous trajectories at odds with common sense. In our analysis, “the particle's path” has operational meaning as acquired by a path-discriminating measurement. For a quantum-mechanical experimental demonstration of the case, one should perform a single-photon version of the experiment by Danan et al. [A. Danan, D. Farfurnik, S. Bar-Ad, and L. Vaidman, Phys. Rev. Lett. 111, 240402 (2013)] with unambiguous path discrimination. We present a detailed proposal for such an experiment.

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Received 25 January 2017

DOI:https://doi.org/10.1103/PhysRevA.96.022126

Physics Subject Headings (PhySH)

Quantum correlations, foundations & formalism Quantum foundations Quantum measurements

General Physics

Authors & Affiliations

Berthold-Georg Englert^1,2,3,*, Kelvin Horia^4,†, Jibo Dai^1,‡, Yink Loong Len^1,§, and Hui Khoon Ng^5,1,3,∥

¹Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
²Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
³MajuLab, Centre National de la Recherche Scientifique, UNS-NUS-NTU International Joint Unit, UMI 3654, Singapore 117543, Singapore
⁴Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
⁵Yale-NUS College, 16 College Avenue West, Singapore 138527, Singapore

^*cqtebg@nus.edu.sg
^†khoria@ntu.edu.sg
^‡Now at Data Storage Institute, A*STAR; dai_jibo@dsi.a-star.edu.sg
^§yinkloong@quantumlah.org
^∥cqtnhk@nus.edu.sg

Comments & Replies

Reply to “Comment on ‘Past of a quantum particle revisited’ ”

Berthold-Georg Englert, Kelvin Horia, Jibo Dai, Yink Loong Len, and Hui Khoon Ng

Phys. Rev. A 99, 026104 (2019)

Comment on “Past of a quantum particle revisited”

Uri Peleg and Lev Vaidman

Phys. Rev. A 99, 026103 (2019)

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Vol. 96, Iss. 2 — August 2017

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