Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Consistent Histories and Quantum Delayed Choice

Robert B. Griffiths

Published Jan 1, 1998• 5 citations
OpenAlex

Abstract

John Wheeler devised a gedanken experiment in which a piece of apparatus can be altered just before the arrival of particle, and this “delayed choice ” can, seemingly, alter the quantum state of the particle at a much earlier time, long before the choice is made. A slightly different gedanken experiment, which exhibits the same conceptual difficulty, is analyzed using the techniques of consistent history quantum theory. The idea that the future influences the past disappears when proper account is taken of the diversity of possible quantum descriptions of the world, and their mutual compatibility or incompatibility. John Wheeler proposed a delayed-choice experiment in which the second beam splitter of a Mach-Zehnder interferometer is or is not removed at the very last instant before a photon reaches it and passes out of the interferometer [1]. A modified version which exhibits essentially the same paradox is shown in Fig. 1. A photon enters the interferometer through channel a, and two detectors in the c and d arms are either (a) left in position, or (b) removed just before the photon reaches (one of) them, so that it is free to proceed on to the second

Related papers

Consistent Histories and Quantum Delayed Choice

Robert B. Griffiths

John Wheeler devised a gedanken experiment in which a piece of apparatus can be altered just before the arrival of particle, and this “delayed choice” can, seemingly, alter the quantum state of the particle at a much earlier time, long before the choice is made. A slightly different gedanken experiment, which exhibits the same conceptual difficulty, is analyzed using the techniques of consistent history quantum theory. The idea that the future influences the past disappears when proper account is taken of the diversity of possible quantum descriptions of the world, and their mutual compatibility or incompatibility.

arXiv:quant-ph/9810016•Fortschritte der Physik•Nov 1, 1998•1 citation

On Wheeler's delayed-choice Gedankenexperiment and its laboratory realization

M Božić, L Vušković, M Davidović +1 more

Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315, 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment. Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits. Given the same incident photon state onto the output beam-splitter, BS_output, the photon's state at the exit will be very different depending on whether BS_output is on or off. Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case. Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BS_output, i.e., after it has exited from the Mach-Zehnder interferometer. The random on/off choice at BS_output has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BS_output.

arXiv:1101.1511•Physica Scripta•Feb 1, 2011•1 citation

On Wheeler’s delayed-choice Gedankenexperiment and its laboratory realization

Ángel S. Sanz

Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment.Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits.Given the same incident photon state onto the output beam-splitter, BSoutput, the photon's state at the exit will be very different depending on whether BSoutput is on or off.Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case.Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BSoutput, i.e., after it has exited from the Mach-Zehnder interferometer.The random on/off choice at BSoutput has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BSoutput.

•Aug 14, 2016•1 citation

Experimental realization of Wheeler’s delayed-choice Gedanken Experiment

V. Jacques, E Wu, Frédéric Grosshans +4 more

Wheeler’s gedanken experiment is the most fascinating and subtle illustration of wave-particle duality [1]. If we consider a single-photon light pulse in a Mach-Zehnder interferometer, one can either measure the interference at the output – evidencing the “wave-like” behavior of the photon- or one can detect the path followed by the photon – evidencing its “particle-like” behavior. In order to pinpoint how surprising this is, John Wheeler considered a “delayed-choice” regime where the choice of measuring either property is done only after the photon has entered the interferometer.

The Rochester Conferences on Coherence and Quantum Optics and the Quantum Information and Measurement meeting•Jan 1, 2007•6 citations

Optical beam splitter, Mach–Zehnder interferometer and the delayed choice issue

Dietrich von der Linde

Abstract John Wheeler's delayed choice thought experiment is often invoked in discussions of the wave-particle duality of quantum physics. Every so often interpretations are offered that do not restrict to straight physics. The key element of the 'Gedankenexperiment' is a Mach–Zehnder interferometer composed of two optical beam splitters. The quantum description of these devices and the treatment of delayed choice experiment in the framework of quantum optics are discussed here.

Applied Physics B•Aug 24, 2021•2 citations

A Quantum Delayed-Choice Experiment

Alberto Peruzzo, Peter Shadbolt, Nicolas Brunner +2 more

Delaying Quantum Choice Photons can display wavelike or particle-like behavior, depending on the experimental technique used to measure them. Understanding this duality lies at the heart of quantum mechanics. In two reports, Peruzzo et al. (p. 634 ) and Kaiser et al. (p. 637 ; see the Perspective on both papers by Lloyd ) perform an entangled version of John Wheeler's delayed-choice gedanken experiment, in which the choice of detection can be changed after a photon passes through a double-slit to avoid the measurement process affecting the state of the photon. The original proposal allowed the wave and particle nature of light to be interchanged after the light had entered the interferometer. By contrast in this study, entanglement allowed the wave and particle nature to be interchanged after the light was detected and revealed the quantum nature of the photon, for example, it displays wave- and particle-like behavior simultaneously.

arXiv:1205.4926•Science•Nov 1, 2012•262 citations
John Wheeler devised a gedanken experiment in which a piece of apparatus can be altered just before the arrival of particle, and this “delayed choice ” can, seemingly, alter the quantum state of the particle at a much earlier time, long before the choice is made. A slightly different gedanken experiment, which exhibits the same conceptual difficulty, is analyzed using the techniques of consistent history quantum theory. The idea that the future influences the past disappears when proper account is taken of the diversity of possible quantum descriptions of the world, and their mutual compatibility or incompatibility. John Wheeler proposed a delayed-choice experiment in which the second beam splitter of a Mach-Zehnder interferometer is or is not removed at the very last instant before a photon reaches it and passes out of the interferometer [1]. A modified version which exhibits essentially the same paradox is shown in Fig. 1. A photon enters the interferometer through channel a, and two detectors in the c and d arms are either (a) left in position, or (b) removed just before the photon reaches (one of) them, so that it is free to proceed on to the second
John Wheeler devised a gedanken experiment in which a piece of apparatus can be altered just before the arrival of particle, and this “delayed choice” can, seemingly, alter the quantum state of the particle at a much earlier time, long before the choice is made. A slightly different gedanken experiment, which exhibits the same conceptual difficulty, is analyzed using the techniques of consistent history quantum theory. The idea that the future influences the past disappears when proper account is taken of the diversity of possible quantum descriptions of the world, and their mutual compatibility or incompatibility.
Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315, 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment. Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits. Given the same incident photon state onto the output beam-splitter, BS_output, the photon's state at the exit will be very different depending on whether BS_output is on or off. Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case. Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BS_output, i.e., after it has exited from the Mach-Zehnder interferometer. The random on/off choice at BS_output has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BS_output.
Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment.Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits.Given the same incident photon state onto the output beam-splitter, BSoutput, the photon's state at the exit will be very different depending on whether BSoutput is on or off.Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case.Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BSoutput, i.e., after it has exited from the Mach-Zehnder interferometer.The random on/off choice at BSoutput has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BSoutput.
Wheeler’s gedanken experiment is the most fascinating and subtle illustration of wave-particle duality [1]. If we consider a single-photon light pulse in a Mach-Zehnder interferometer, one can either measure the interference at the output – evidencing the “wave-like” behavior of the photon- or one can detect the path followed by the photon – evidencing its “particle-like” behavior. In order to pinpoint how surprising this is, John Wheeler considered a “delayed-choice” regime where the choice of measuring either property is done only after the photon has entered the interferometer.
Delaying Quantum Choice Photons can display wavelike or particle-like behavior, depending on the experimental technique used to measure them. Understanding this duality lies at the heart of quantum mechanics. In two reports, Peruzzo et al. (p. 634 ) and Kaiser et al. (p. 637 ; see the Perspective on both papers by Lloyd ) perform an entangled version of John Wheeler's delayed-choice gedanken experiment, in which the choice of detection can be changed after a photon passes through a double-slit to avoid the measurement process affecting the state of the photon. The original proposal allowed the wave and particle nature of light to be interchanged after the light had entered the interferometer. By contrast in this study, entanglement allowed the wave and particle nature to be interchanged after the light was detected and revealed the quantum nature of the photon, for example, it displays wave- and particle-like behavior simultaneously.