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

Europhysics news

The end to 100 years of “wave-particle duality” mystery in quantum physics

J. Bernabéu

Published Jan 1, 2025• 2 citations
Publisher

Abstract

The wave-particle duality mystery, present in the language of quantum physics since its historical origins 100 years ago, has no real correspondence with the actual behaviour of nature when it is observed. The dilemma of the so-called “single particle interference” experiments is not between particles versus waves: the interference in quantum physics is between probability amplitudes for different untagged alternatives in a definite transition between states. This article shows that the same conceptual basis is involved in a plethora of “two-state systems” as a consequence of the linear superposition principle, no matter whether the observables refer to either spatial or internal properties. Several examples, from the Young double-slit interference experiments to neutrino flavour oscillation experiments, are discussed in a common interpretation language.

DOI
10.1051/epn/2025209

Related papers

DOUBLE SLIT EXPERIMENT AND WAVE-PARTICLE DUALITY

V. Abbasov

Abstract The double-slit experiment is a classic experiment that presents the clearest manifestation of wave-particle duality, one of the fundamental principles of quantum mechanics. The double-slit experiment still remains the phenomenon that demonstrates wave-particle duality at the most fundamental level. This phenomenon quantitatively and conceptually demonstrates that microscopic objects can behave like both waves and particles at the same time. This article provides an in-depth analysis of the physical nature of dualism, the mechanism of formation of the interference pattern, and the impact of the act of observation on the dynamics of quantum systems. The need for a new perspective on this topic is due to the fact that the current uncertainty in the interpretation of quantum reality has not yet been completely eliminated, and the boundaries between classical and quantum behavior in microscopic objects are still being explored. The results presented here restructure the deep mechanisms of the interference picture, more clearly frame the relationship between observation and wavefunction collapse, and provide a quantum. Since the article attempts to provide a complete answer to the mechanism of the formation of wave-particle duality, extensive space is given to sections such as historical development, theoretical models, modern research, etc. New approaches to this phenomenon have been developed using modern research and string theory. As a result, a new mathematical expression has been proposed that explains the reasons for the initial emergence of wave-particle duality, and is also important for string theory. The article explains the measurement problem with a more effective physical structure and ontological model.

•Jun 26, 2026•0 citations

On the wave nature of particles

Berat Tuğrul Uğurlu

The main goal of the present article is to elucidate the wave-particle duality problem by giving an unambiguous mathematical expression of the origin of the wave nature of particles. It is indicated that the wave nature of particles is originated from the multidimensional universe approach and under the one-dimensional universe assumption the wave nature vanishes. The one-dimensional universe assumption also gives a deterministic explanation for the double-slit experiment and answers how a single electron can interfere with itself. The locality paradox is also discussed. It is demonstrated that the same principle shows how a local measurement can determine the state of a distant system. The theoretical framework presented here may help us to understand various quantum physics phenomena. i.e., the superposition principle, wave function collapse, and entanglement.

Physics Essays•Jun 10, 2022•0 citations

Two Slit Interference, Graphical Representation

Kamal L Rajpal

Thomas Young’s interference experiment (1803) is very simple to perform but, even after more than 200 years is one of the most difficult to understand. Quantum physics offers a mathematical model for the observed wave-particle dualism. This article gives a physical model for the wave-particle duality nature of photons.

•Mar 1, 2013•0 citations

Wave Particle Duality and the Afshar Experiment

Aurélien Drezet

In an interesting series of articles published few years ago Afshar and coworkers [1,2] reported an optical experiment in which they claimed to refute the well known N. Bohr principle of complementarity [3, 4]. Obviously this result, if justified, would constitute a serious attack against the orthodox interpretation of quantum mechanics (known as the Copenhagen interpretation). This work stirred much debate in different journals (see for examples references [5–12]). We think however that there are still some important misunderstandings concerning the interpretation of this experiment. In a preprint written originally in 2004 [5] (and following some early discussions with Afshar) we claimed already that the interpretation by Afshar et al. can be easily stated if we stay as close as possible from the texts written by Bohr. The aim of the present article (which was initially written in 2005 to precise a bit the thought developed in [5]) is to comment the interpretation discussed in [1]. We will in the following analyze the meaning of Bohr principle and show that far from disproving its content the experiment [1] is actually a complete confirmation of its general validity. The difficulties associated with the understanding of this principle are not new and actually complementarity created troubles even in Einstein mind [3] so that we are here in good company. To summarize a bit emphatically Bohr’s complementarity we here remind that this principle states that if one of a pair of non commuting observables of a quantum object is known for sure, then information about the second (complementary) is lost [3, 4, 15, 16]. This can be equivalently expressed as a kind of duality between different descriptions of the quantum system associated with different experimental arrangements which mutually exclude each other (read in particular [3,4]). Later in the discussion we will try to precise this definition but for the moment it is enough to illustrate the concepts by examples Consider for instance the well known Young double-pinholes interference experiment made with photons. The discrete nature of light precludes the simultaneous observation of a same photon in the aperture plane and in the interference pattern: the photon cannot be absorbed twice. This is already a trivial manifestation of the principle of Bohr. Here it implies that the two statistical patterns associated with the wave in the aperture plane and its Fourier (i. e., momentum) transform require necessarily different photons for their recording. It is in that sense that each experiment excludes and completes reciprocally the other. In the case considered before the photon is absorbed during the first detection (this clearly precludes any other detection). However even a non-destructive solution for detection implying entanglement with other quantum systems has a radical effect of the same nature: the complementarity principle is still valid. For example, during their debate Bohr and Einstein [3] discussed an ideal which-way experiment in which the recoil of the slits is correlated to the motion of the photon. Momentum conservation added to arguments based on the uncertainty relations are sufficient to explain how such entanglement photon-slits can erase fringes [15–19]. It is also important for the present discussion to remind that the principle of complementarity has a perfidious consequence on the experimental meaning of trajectory and path followed by a particle. Indeed the unavoidable interactions existing between photons and detectors imply that a trajectory existing independently of any measurement process cannot be unambiguously defined. This sounds even like a tragedy when we consider once again the two-holes experiment. Indeed for Bohr this kind of experiments shows definitely the essential element of ambiguity which is involved in ascribing conventional physical attributes to quantum systems. Intuitively (i. e., from the point of view of classical particle dynamic) one would expect that a photon detected in the focal plane of the lens must have crossed only one of the hole 1 or 2 before to reach its final destination. However, if this is true, one can not intuitively understand how the presence of the second hole (through which the photon evidently did not go) forces the photon to participate to an interference pattern (which obviously needs an influence coming from both holes). Explanations to solve this paradox have been proposed by de Broglie, Bohm, and others using concepts such as empty waves or quantum potentials [20, 21]. However all these explanations are in agreement with Bohr principle (since they fully reproduce quantum predictions) and can not be experimentally distinguished. Bohr and Heisenberg proposed for all needed purposes a much more pragmatic and simpler answer: don’t bother, the complementarity principle precludes the simultaneous observation of a photon trajectory and of an interference pattern. For Bohr [3]: This point is of great logical consequence, since it is only the circumstance that we are presented with a choice of either tracing the path

•Jan 1, 2011•5 citations

An experiment to improve understanding wave-particle duality

Michel Gondran, Alexandre Gondran

This article presents an experiment that can be conducted today and that could provide a deeper understanding of the interaction between the wave and particle aspects of an atom. The wave-particle duality is often presented as mutually exclusive: one considers either the wave aspect or the particle aspect. Our proposed experiment involves both aspects simultaneously and raises new questions. It is a slightly modified version of Young's double-slit interference experiment (a grid of narrow slits is added between the two wide slits) and is carried out using Rydberg atoms. Young-type interference experiments typically involve only the de Broglie wave $ψ$, which depends solely on the mass and velocity of the atoms. However, with Rydberg atoms having a large principal quantum number, the ``size'' of the atom-particle also becomes significant. The two large slits are wide enough to allow the Rydberg atoms to pass through, whereas the grid of narrow slits prevents them from passing through. We numerically simulate the possible outcomes based on different hypotheses regarding wave-particle interaction. Conducting the experiment in practice would allow us to distinguish between these hypotheses and deepen our understanding of wave-particle interaction. The conceptual framework of Louis de Broglie's double solution theory is well-suited to this experiment because it distinguishes between two types of waves: an external or statistical wave (de Broglie's wave) and an internal or physical wave (corresponding to the physical particle). We will examine the relevance of this approach.

arXiv:2509.04882•Sep 5, 2025•0 citations

An experiment to improve our understanding wave-particle duality

Alexandre Gondran, Michel Gondran

This article presents an experiment that can be conducted today and that could provide a deeper understanding of the interaction between the wave and particle aspects of an atom. The wave-particle duality is often presented as mutually exclusive: one considers either the wave aspect or the particle aspect. Our proposed experiment involves both aspects simultaneously and raises new questions. It is a slightly modified version of Young’s double-slit interference experiment (a grid of narrow slits is added between the two wide slits) and is carried out using Rydberg atoms. Young-type interference experiments typically involve only the de Broglie wave ψ , which depends solely on the mass and velocity of the atoms. However, with Rydberg atoms having a large principal quantum number, the ”size” of the atom-particle also becomes significant. The two large slits are wide enough to allow the Rydberg atoms to pass through, whereas the grid of narrow slits prevents them from passing through. We numerically simulate the possible outcomes based on different hypotheses regarding wave-particle interaction. Conducting the experiment in practice would allow us to distinguish between these hypotheses and deepen our understanding of wave-particle interaction. The conceptual framework of Louis de Broglie’s double solution theory is well-suited to this experiment because it distinguishes between two types of waves: an external or statistical wave (de Broglie’s wave) and an internal or physical wave (corresponding to the physical particle). We will examine the relevance of this approach.

Physics Letters A•Sep 5, 2026•0 citations
The wave-particle duality mystery, present in the language of quantum physics since its historical origins 100 years ago, has no real correspondence with the actual behaviour of nature when it is observed. The dilemma of the so-called “single particle interference” experiments is not between particles versus waves: the interference in quantum physics is between probability amplitudes for different untagged alternatives in a definite transition between states. This article shows that the same conceptual basis is involved in a plethora of “two-state systems” as a consequence of the linear superposition principle, no matter whether the observables refer to either spatial or internal properties. Several examples, from the Young double-slit interference experiments to neutrino flavour oscillation experiments, are discussed in a common interpretation language.
Abstract The double-slit experiment is a classic experiment that presents the clearest manifestation of wave-particle duality, one of the fundamental principles of quantum mechanics. The double-slit experiment still remains the phenomenon that demonstrates wave-particle duality at the most fundamental level. This phenomenon quantitatively and conceptually demonstrates that microscopic objects can behave like both waves and particles at the same time. This article provides an in-depth analysis of the physical nature of dualism, the mechanism of formation of the interference pattern, and the impact of the act of observation on the dynamics of quantum systems. The need for a new perspective on this topic is due to the fact that the current uncertainty in the interpretation of quantum reality has not yet been completely eliminated, and the boundaries between classical and quantum behavior in microscopic objects are still being explored. The results presented here restructure the deep mechanisms of the interference picture, more clearly frame the relationship between observation and wavefunction collapse, and provide a quantum. Since the article attempts to provide a complete answer to the mechanism of the formation of wave-particle duality, extensive space is given to sections such as historical development, theoretical models, modern research, etc. New approaches to this phenomenon have been developed using modern research and string theory. As a result, a new mathematical expression has been proposed that explains the reasons for the initial emergence of wave-particle duality, and is also important for string theory. The article explains the measurement problem with a more effective physical structure and ontological model.
The main goal of the present article is to elucidate the wave-particle duality problem by giving an unambiguous mathematical expression of the origin of the wave nature of particles. It is indicated that the wave nature of particles is originated from the multidimensional universe approach and under the one-dimensional universe assumption the wave nature vanishes. The one-dimensional universe assumption also gives a deterministic explanation for the double-slit experiment and answers how a single electron can interfere with itself. The locality paradox is also discussed. It is demonstrated that the same principle shows how a local measurement can determine the state of a distant system. The theoretical framework presented here may help us to understand various quantum physics phenomena. i.e., the superposition principle, wave function collapse, and entanglement.
In an interesting series of articles published few years ago Afshar and coworkers [1,2] reported an optical experiment in which they claimed to refute the well known N. Bohr principle of complementarity [3, 4]. Obviously this result, if justified, would constitute a serious attack against the orthodox interpretation of quantum mechanics (known as the Copenhagen interpretation). This work stirred much debate in different journals (see for examples references [5–12]). We think however that there are still some important misunderstandings concerning the interpretation of this experiment. In a preprint written originally in 2004 [5] (and following some early discussions with Afshar) we claimed already that the interpretation by Afshar et al. can be easily stated if we stay as close as possible from the texts written by Bohr. The aim of the present article (which was initially written in 2005 to precise a bit the thought developed in [5]) is to comment the interpretation discussed in [1]. We will in the following analyze the meaning of Bohr principle and show that far from disproving its content the experiment [1] is actually a complete confirmation of its general validity. The difficulties associated with the understanding of this principle are not new and actually complementarity created troubles even in Einstein mind [3] so that we are here in good company. To summarize a bit emphatically Bohr’s complementarity we here remind that this principle states that if one of a pair of non commuting observables of a quantum object is known for sure, then information about the second (complementary) is lost [3, 4, 15, 16]. This can be equivalently expressed as a kind of duality between different descriptions of the quantum system associated with different experimental arrangements which mutually exclude each other (read in particular [3,4]). Later in the discussion we will try to precise this definition but for the moment it is enough to illustrate the concepts by examples Consider for instance the well known Young double-pinholes interference experiment made with photons. The discrete nature of light precludes the simultaneous observation of a same photon in the aperture plane and in the interference pattern: the photon cannot be absorbed twice. This is already a trivial manifestation of the principle of Bohr. Here it implies that the two statistical patterns associated with the wave in the aperture plane and its Fourier (i. e., momentum) transform require necessarily different photons for their recording. It is in that sense that each experiment excludes and completes reciprocally the other. In the case considered before the photon is absorbed during the first detection (this clearly precludes any other detection). However even a non-destructive solution for detection implying entanglement with other quantum systems has a radical effect of the same nature: the complementarity principle is still valid. For example, during their debate Bohr and Einstein [3] discussed an ideal which-way experiment in which the recoil of the slits is correlated to the motion of the photon. Momentum conservation added to arguments based on the uncertainty relations are sufficient to explain how such entanglement photon-slits can erase fringes [15–19]. It is also important for the present discussion to remind that the principle of complementarity has a perfidious consequence on the experimental meaning of trajectory and path followed by a particle. Indeed the unavoidable interactions existing between photons and detectors imply that a trajectory existing independently of any measurement process cannot be unambiguously defined. This sounds even like a tragedy when we consider once again the two-holes experiment. Indeed for Bohr this kind of experiments shows definitely the essential element of ambiguity which is involved in ascribing conventional physical attributes to quantum systems. Intuitively (i. e., from the point of view of classical particle dynamic) one would expect that a photon detected in the focal plane of the lens must have crossed only one of the hole 1 or 2 before to reach its final destination. However, if this is true, one can not intuitively understand how the presence of the second hole (through which the photon evidently did not go) forces the photon to participate to an interference pattern (which obviously needs an influence coming from both holes). Explanations to solve this paradox have been proposed by de Broglie, Bohm, and others using concepts such as empty waves or quantum potentials [20, 21]. However all these explanations are in agreement with Bohr principle (since they fully reproduce quantum predictions) and can not be experimentally distinguished. Bohr and Heisenberg proposed for all needed purposes a much more pragmatic and simpler answer: don’t bother, the complementarity principle precludes the simultaneous observation of a photon trajectory and of an interference pattern. For Bohr [3]: This point is of great logical consequence, since it is only the circumstance that we are presented with a choice of either tracing the path
This article presents an experiment that can be conducted today and that could provide a deeper understanding of the interaction between the wave and particle aspects of an atom. The wave-particle duality is often presented as mutually exclusive: one considers either the wave aspect or the particle aspect. Our proposed experiment involves both aspects simultaneously and raises new questions. It is a slightly modified version of Young's double-slit interference experiment (a grid of narrow slits is added between the two wide slits) and is carried out using Rydberg atoms. Young-type interference experiments typically involve only the de Broglie wave ψψψ, which depends solely on the mass and velocity of the atoms. However, with Rydberg atoms having a large principal quantum number, the ``size'' of the atom-particle also becomes significant. The two large slits are wide enough to allow the Rydberg atoms to pass through, whereas the grid of narrow slits prevents them from passing through. We numerically simulate the possible outcomes based on different hypotheses regarding wave-particle interaction. Conducting the experiment in practice would allow us to distinguish between these hypotheses and deepen our understanding of wave-particle interaction. The conceptual framework of Louis de Broglie's double solution theory is well-suited to this experiment because it distinguishes between two types of waves: an external or statistical wave (de Broglie's wave) and an internal or physical wave (corresponding to the physical particle). We will examine the relevance of this approach.
This article presents an experiment that can be conducted today and that could provide a deeper understanding of the interaction between the wave and particle aspects of an atom. The wave-particle duality is often presented as mutually exclusive: one considers either the wave aspect or the particle aspect. Our proposed experiment involves both aspects simultaneously and raises new questions. It is a slightly modified version of Young’s double-slit interference experiment (a grid of narrow slits is added between the two wide slits) and is carried out using Rydberg atoms. Young-type interference experiments typically involve only the de Broglie wave ψ , which depends solely on the mass and velocity of the atoms. However, with Rydberg atoms having a large principal quantum number, the ”size” of the atom-particle also becomes significant. The two large slits are wide enough to allow the Rydberg atoms to pass through, whereas the grid of narrow slits prevents them from passing through. We numerically simulate the possible outcomes based on different hypotheses regarding wave-particle interaction. Conducting the experiment in practice would allow us to distinguish between these hypotheses and deepen our understanding of wave-particle interaction. The conceptual framework of Louis de Broglie’s double solution theory is well-suited to this experiment because it distinguishes between two types of waves: an external or statistical wave (de Broglie’s wave) and an internal or physical wave (corresponding to the physical particle). We will examine the relevance of this approach.