The double-slit experiment is one of the most important demonstrations of interference and hasplayed a central role in understanding wave behaviour and measurement in physics. In quantummechanical discussions, the availability of which-path information is associated with changes ininterference behaviour. This paper presents a double-slit thought experiment using microwave electromagnetic waves to examine the relationship between electromagnetic energy distribution andwhich-path information.Microwave double-slit experiments have demonstrated interference patterns by measuring electromagnetic intensity using antennas. In the present thought experiment, the same electromagneticwave arrangement is considered with different measurement approaches: localized detection of electromagnetic interactions and measurement of electromagnetic energy distribution at the two slitlocations.The central question addressed is whether electromagnetic energy detection at both slits providesinformation related to which-path information. The purpose of this work is to examine how differentforms of measurement information may be interpreted together.
The double-slit experiment is one of the most important demonstrations of interference and hasplayed a central role in understanding wave behaviour and measurement in physics. In quantummechanical discussions, the availability of which-path information is associated with changes ininterference behaviour. This paper presents a double-slit thought experiment using microwave electromagnetic waves to examine the relationship between electromagnetic energy distribution andwhich-path information.Microwave double-slit experiments have demonstrated interference patterns by measuring electromagnetic intensity using antennas. In the present thought experiment, the same electromagneticwave arrangement is considered with different measurement approaches: localized detection of electromagnetic interactions and measurement of electromagnetic energy distribution at the two slitlocations.The central question addressed is whether electromagnetic energy detection at both slits providesinformation related to which-path information. The purpose of this work is to examine how differentforms of measurement information may be interpreted together.
Double-double-slit thought experiment provides profound insight on interference of quantum entangled particles. This paper presents a detailed experimental realisation of quantum double-double-slit thought experiment with momentum entangled photons and theoretical analysis of the experiment. Experiment is configured in such a way that photons are path entangled and each photon can reveal the which-slit path information of the other photon. As a consequence, single photon interference is suppressed. However, two-photon interference pattern appears if locations of detection of photons are correlated without revealing the which-slit path information. It is also shown experimentally and theoretically that two-photon quantum interference disappears when the which-slit path of a photon in the double-double-slit is detected.
## AbstractA deterministic interpretation of the double-slit experiment is proposed, in which the electron is treated as a localized particle at all times. The observed interference pattern is attributed to a real physical energy wave in the electromagnetic field, generated by the electron's accelerated motion through the field. This energy wave reaches the slit barrier, where the slit geometry creates coherent waves that merge to form a constructive interference wave. This wave redistributes energy in the field, creating an Electron-EMF coupled pathway that guides the particle to the detector. The apparent randomness of individual impacts arises from incomplete knowledge of the initial conditions, not from intrinsic indeterminism. The measurement effect is modelled as a disturbance of the coherent energy waves, either preventing the formation of the coupled pathway or destroying it after formation. The model is extended to the quantum eraser experiment, where the restoration of coherence via a polarizer naturally explains the reappearance of interference. A further extension to the delayed-choice quantum eraser is proposed, introducing the Entangled Constructive Interference Wave (ECIW) as a physical mechanism for entanglement within the model. The mechanism is shown to apply across geometries beyond the double slit. Predictions include a correlation between landing position and flight time, offering a testable distinction from standard quantum mechanical interpretations. A preliminary, illustrative mathematical framework is provided, situating the model within the pilot-wave tradition. **Keywords: ** Double-slit experiment, pilot wave, electromagnetic field, quantum interpretation, determinism, hidden variables, measurement problem, energy wave, coupled pathway, quantum eraser, delayed-choice quantum eraser, entanglement.
The double-slit experiment has stood for a century as the paradigmatic demonstration of quantum superposition: the standard interpretation holds that a particle passes through both slits simultaneously, existing in a superposition of two spatially separated states. This paper proposes a physically distinct alternative: the particle's matter wave — a real physical wave propagating through space in accordance with de Broglie's relation λ = h/p — passes through both slits, while the particle itself (matter) remains in an undetermined state until a constructive interference maximum is formed at the detection screen. The particle does not simultaneously occupy two locations; the wave does. This distinction eliminates the need for superposition as an ontological commitment while fully reproducing the observed interference pattern. We further show that the disappearance of the interference pattern upon which-path measurement is explained without invoking wavefunction collapse: the measurement interaction redirects the matter wave to a single-slit geometry, eliminating the two-wave interference condition. Three experimentally testable predictions distinguish this framework from the standard interpretation: (1) weak-measurement trajectory reconstruction should reveal single particle paths inconsistent with simultaneous two-slit passage; (2) diffraction fringe spacing should depend on the mass density of the slit material, because denser slit edges generate a steeper refractive-index gradient for the matter wave; (3) the fringe pattern should exhibit a density-dependent phase shift measurable with current matter-wave interferometry technology. This reinterpretation requires no new mathematical formalism — the Schrödinger equation and Born's rule are retained — but replaces the ontological claim of simultaneous multi-location existence with the physically consistent picture of matter-wave propagation through an undetermined-state particle.
This paper considers a theoretical model of the double-slit experiment with electrons whose paths are monitored. This monitoring, inspired by a recent text by Maudlin, is performed by the Coulomb scattering of the electron by a proton. A simple quantum mechanical calculation is presented, inspired in part by a recent experimental demonstration of this famous thought experiment. The results illustrate the relationship between entanglement and the loss of coherence in the interference pattern. The tradeoff between the visibility of interference and the information gained by measurement is also explored. This calculation can provide advanced undergraduates insight into decoherence, entanglement, and quantum information.
The puzzles of quantum mechanics are: 1. What is the medium for the photon and for the electron wave? i.e. what is waving? 2. How can a particle have an interference pattern 3. Observer effect. 4. Entanglement. In Quantum Erasure and Double-Slit experiments, how does the emitter know to direct the photon two both slits or only to one slit? And how does the detector know where to detect the photons to form an interference pattern and not a bell-shaped (Gaussian) pattern or vice versa? This paper proposes that the hint in the mystery of light waves without a medium (ether) is contained in the Planck’s relation itself: E = hf. It is shown that Planck’s relation itself hints on the mystery of light waves without medium, and is a consequence or manifestation of non-existence of a medium for light propagation. The subtle law of nature that has eluded physicists so far is that the photon energy density ( amplitude of electric and magnetic fields) at a given point in the spatial dimensions of the photon is directly related to the rate of change of the electric and magnetic fields at that point. The higher the frequency of the photon, the higher the rate of change of the fields at every point for that photon, compared to a photon of lower frequency. The higher the rate of change of the fields at a given point, the higher the amplitude of oscillation of the electric and magnetic fields at that point. It follows that the higher the frequency of the photon and the higher the amplitude of the electric and magnetic fields, which results in high intensity of vibration of the photon, the more localized it will be. A high frequency photon will spread less in space than a lower frequency photon of equal envelope amplitude because, if the high frequency photon spreads out, there would be high rates of change over a wider region of space, and the total energy would be greater than the finite photon energy. The photon energy will always be concentrated at regions of high rate of change of electric and magnetic fields. This theory explains how electric and magnetic fields can be their own ‘medium’ , 'dragging' of the electromagnetic energy by the wave, hence eliminating the need for any medium. Since the electromagnetic wave (the photon) is a traveling disturbance of electric and magnetic fields, the rate of change of the fields at a point in space will create the intensity (amplitude) of the fields at that point. Likewise, the electron wave is a travelling disturbance of the electron mass density wave on the electron ‘sea’. The higher the frequency of mass density variation of the electron at a given point of space, the higher the mass density of the electron at that point. This will make the electron ( the electron ‘sea’) its own medium of propagation. i.e. the electron ‘sea’ is the medium of propagation for the electron wave. This means that the electron wave 'drags' the electron with itself. The other theory proposed in this paper is the predetermination of interference fringes in double-slit experiments and predetermination of which slit the photon takes in which-way or quantum erasure experiments. We propose a fundamental law of nature that an electron, an atom or any source of electromagnetic waves will always emit a weak, continuous electromagnetic energy even when not excited, which implies that electrons and atoms are always in continuous, fundamental, weak vibrations (accelerations). Therefore, in double-slit experiments and in quantum erasure or which-way experiments, the atom (electron) of the light source is always emitting weak, continuous electromagnetic waves, even before the atom is excited. Therefore, even before the atom/the electron of the light source starts emitting a photon, a weak electromagnetic (light) wave exists as an entity, extending all the way from the light source (the atom) to the slits and to the detecting screen. This ‘precursor’ wave serves as the 'highway' for the propagation of the main photon energy packet, both of which are coherent and exist as an entity. When the atom is excited, it will just emit a photon that is coherent with the weak wave it had already been emitting continuously. Therefore, even before the atom is excited, a weak wave interference pattern already exists on the screen. The photon emitted after excitation simply follows the path already created by the weak ‘precursor’ wave and will land on the screen according to the predetermined interference pattern, collapsing to the point of detection at the instant of detection. The path to be taken by the photon is predetermined in which-way or quantum erasure experiments. The same theory explains quantum entanglement: the polarization of two entangled photons is predetermined even before the excitation of the atoms emitting the photons.
This paper reviews humanity's understanding of photons, the evolution of quantum mechanics and quantum electrodynamics (QED), and analyzes their physical interpretations and philosophical implications. It attempts to uncover the true nature of photons by exploring possible hidden variables in the double-slit experiment. The wave-particle duality of photons, as posited by quantum mechanics, appears to me to lack verisimilitude. By designing a thought experiment involving a photon double-slit setup, I seek to falsify the notion that photons generate coherence, or so-called wave-function superposition, within the light field between the slits and the screen. This endeavour aims to demonstrate the pure particle nature of photons. This paper further explores the intrinsic relationship between electromagnetic waves and photons by examining the wavelength of electromagnetic radiation. It posits that electromagnetic waves are fundamentally pure particle-waves. An analysis of QED elucidates the potential influence of photon momentum on photon interactions, an effect that could have profound implications for quantum information transmission. This paper explores the non-wave-particle duality of photons through the double-slit experiment and the double-slit observer experiment. The essence of photons is purely particle-like. The thought experiment of the photon double-slit experiment is pivotal in demonstrating that photons and other particles—such as electrons, atoms, and macromolecules—are purely particulate in nature. Moreover, in space, photons can interfere with each other's paths based on their momentum. This can simultaneously alter the trajectory of photons and even modify their velocity. That is to say, a photon beam possessing greater momentum may carry along a portion of photon beams with lesser momentum, propagating them over considerable distances. The wavelength of a light wave fundamentally represents the distance between consecutive photons as they queue and advance through space. A longer wavelength corresponds to a greater distance between photons, causing them to diverge more widely in space, as seen with radio waves. Conversely, a shorter wavelength implies closer proximity between photons, resulting in denser emission and a highly directional nature, as seen in gamma rays. Photons within the visible spectrum may occasionally transmit information bearing specific content. This information, conveyed via photons, can propagate over distances ranging from several metres to thousands of kilometres.