Quantum mechanics fails to explain double-slit photon interference.

Quantum mechanics fails to explain double-slit photon interference. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Quantum mechanics fails to explain double-slit photon interference. Janusz W. Rajkowski This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3425560/v2 This work is licensed under a CC BY 4.0 License Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Abstract In a modified double-slit experiment, a laser beam is split evenly by a wall that separates the two half-beams around the slits. This setup continues to generate a standard double-slit pattern of interference. The experiment is ruling out the feasibility of interference through quantum superposition. Theoretical Physics Figures Figure 1 Introduction Young’s interference experiment was critical in advancing the classical wave theory of light. The same experiment was later recognized as providing evidence for the principles of quantum mechanics [1-5]. Based on the Copenhagen interpretation, a photon can interfere when passing through two adjacent apertures [6] in superposition. The present experiment provides new insights into double-slit interference. The experiment follows Young’s original double-slit design. Choosing the classical double-slit arrangement allowed for modifying the interferometer by installing a beam-dividing wall. This provided an opportunity to compare the interference produced in a standard double-slit configuration with interference in a setup with wall-divided slits, where the photon’s interaction with two slits is restricted or prevented. The similarity of interference patterns recorded on both setups favors the classical interpretation of interference. Methods and Results The double-slit setup was assembled from individual components to add flexibility in exploring new aspects of double-slit interference. Among these components, the opaque strip (2) shown in Figs. 1A, C, and E, and a divider wall (3) appearing in Figs. 1B, D, and F are two alternative beam-splitting parts of the double-slit apparatus. Sidewalls (4) are two opaque elements perpendicular to the beam. All settings were made with the qualitative accuracy of visual guidance, and interference patterns were also evaluated visually. A low-power laser module (Quarton VLM-650-02 LPA) was used to shine light at an opaque obstruction with two parallel slits, producing interference images on a screen located over 5 meters away. These images were photographed from the screen that was angled to stretch a fringe pattern and are displayed on top of each of the six panels of Fig. 1. An opaque strip (2) (a round steel rod 0.5 mm in diameter) was placed 40 mm from the laser exit lens, and at the center of the laser beam, Fig. 1A. A double-slit configuration was completed by installing two opaque iron sidewalls (4) on each side of the beam-splitting components, Fig. 1C and D, leaving a narrow (~0.2 mm) gap between the straight edge of each sidewall and the center part. Each gap was further adjusted to sharpen the fringe pattern. Because sidewalls (4) were mounted on separate positioners, they could be moved several centimeters along the longitudinal axis of the laser beam while maintaining a fixed distance from the beam axis, Fig. 1E. The tests in Fig. 1B, D, and E show a divider wall (3) (an iron plate of dimensions 80x13x0.5 mm) used in place of the opaque strip (2). The divider (3) was mounted against the laser lens (1) and extended 80 mm forward. The divider wall was adjusted to be precisely parallel to and at the center of the laser beam. Results The experiment compared two beam-splitting configurations: one with an opaque strip (2) and one with a divider (3). Besides splitting the beam, the divider wall had an additional role in isolating the left half-beam from the right one over 80mm of the beam’s trajectory. Both arrangements produced similar interference patterns illustrated in Fig. 1A, C, D versus B, D, and F. Furthermore, despite moving the sidewalls from their original position (Figs 1C and D) to a new position, such as in Figs 1E and F, the corresponding patterns of fringes remained unchanged. Removing the sidewalls from the laser beam path, as in Fig. 1C and D, resulted in images in Fig. 1A and B, which are typical of an opaque strip. Discussion The phenomenon of light interference in a double-slit experiment is still a matter of debate [1-3, 6-8]. While interference can be explained using the classical concept of wave interference, it can also be explained within the framework of quantum mechanics. According to the latter hypothesis, a photon can interact with both slits simultaneously, which provides the rationale for single-photon interference. Our experiment has raised questions about this scenario. We found that the pattern of fringes produced by the wall-divided slits was the same as that produced by the original double-slit setup. Also, when the components of the slit assembly were grossly misaligned, as shown in Fig. 1E and F, the interference pattern remained unaffected. Since the barrier between the two slits firmly ensures that a photon can pass only through a single slit, our experiment casts doubt on any interpretation involving simultaneous interaction with two slits, such as quantum superposition, wavefunction, or a pilot wave. Despite its conceptual ambiguity, the double-slit experiment has proven instrumental in the development of successful quantum theory. However, certain aspects of the experiment remain in need of clarification. References 1. Young, T.: The Bakerian lecture. Experiments and calculations relative to physical optics. Philosophical Transactions of the Royal Society of London. 94, 1-16, (1804) 2. Ronchi, V.: The Nature of Light. Cambridge: Harward University Press, (1970) 3. Ananthaswamy, A. Through Two Doors at Once: The Elegant Experiment That Captivates the Enigma of Our Quantum Reality. Duckworth, U.K. (2020) 4. Sir Geoffrey, I. T.: Interference Fringes with Feeble Light. Prof. Cam. Phil. Soc. 15, 114, (1909) 5. Ruekner, W., and Peidle, J.: Young’s double-slit experiment with single photons and quantum eraser. American Journal of Physics 81, 951-958 (2013) 6. Lewis, P.J.: Interpretations of Quantum Mechanics, Internet Encyclopedia of Philosophy. https://iep.utm.edu/int-qm/ . Accessed 3 October 2023 7. Goldstein, S.: Bohmian Mechanics, Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/qm-bohm/. (2001). Accessed 3 October 2023 8. Feinman, R. P. QED. The Strange Theory of Light and Matter. Princeton University Press (2014) Additional Declarations The authors declare no competing interests. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3425560","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":239731177,"identity":"70412300-3ff2-431e-9530-bd3a70a96901","order_by":0,"name":"Janusz W. Rajkowski","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYHACxscgkg3MNiBOC7MxkJBgY2AmXgubNEgLA1gLMcC8/YxZdUHNnTo+9vPHpAsK7tg1sB8+ugGfFpkzOWa3Zxx7JsHGk8wmPcPgWXIDT1raDXxaJBiAWnjYDkuwSTCzSfMYHE5mkOAxw6+F/41ZMc8/krRI5Jgx87YhtNgRoeVZsTRv3zPJNp5kY+sZBocT2Aj6hT9542eeb3f45dsPPrxd8OewPT/74WN4tTAwcICi7wCIxQKKoMQ2/MpBgP0BTAvzZyBhT1jHKBgFo2AUjDQAAG6dQHfFZ30NAAAAAElFTkSuQmCC","orcid":"","institution":"non-affiliated","correspondingAuthor":true,"prefix":"","firstName":"Janusz","middleName":"W.","lastName":"Rajkowski","suffix":""}],"badges":[],"createdAt":"2023-10-10 00:44:09","currentVersionCode":2,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-3425560/v2","doiUrl":"https://doi.org/10.21203/rs.3.rs-3425560/v2","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":51433756,"identity":"4cf2ebc4-f0bd-4ee8-8336-1573888451f3","added_by":"auto","created_at":"2024-02-21 14:25:58","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":131573,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDiagram of the experimental arrangement \u003c/strong\u003e(top view). Labels include (1) the laser lens, (2) an opaque strip, (3) a divider, and (4) a sidewall. On top of the panels A-F are the photographic negatives of interference images. When comparing panels A, C, and E to B, D, and F, they display similar pattern quality despite differing in detail.\u003c/p\u003e","description":"","filename":"QMdivider25.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3425560/v2/e80168332c17920ac4d46738.jpg"},{"id":51434368,"identity":"3d5a57e6-88fb-4081-ac84-23840c32a6ee","added_by":"auto","created_at":"2024-02-21 14:33:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":152435,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3425560/v2/baa171cf-5ab0-430c-93e4-81f403c24843.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eQuantum mechanics fails to explain double-slit photon interference.\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eYoung\u0026rsquo;s interference experiment was critical in advancing the classical wave theory of light. The same experiment was later recognized as providing evidence for the principles of quantum mechanics [1-5]. Based on the Copenhagen interpretation, a photon can interfere when passing through two adjacent apertures [6] in superposition. The present experiment provides new insights into double-slit interference.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe experiment follows Young\u0026rsquo;s original double-slit design. Choosing the classical double-slit arrangement allowed for modifying the interferometer by installing a beam-dividing wall. This provided an opportunity to compare the interference produced in a standard double-slit configuration with interference in a setup with wall-divided slits, where the photon\u0026rsquo;s interaction with two slits is restricted or prevented. The similarity of interference patterns recorded on both setups favors the classical interpretation of interference.\u0026nbsp;\u003c/p\u003e"},{"header":"Methods and Results","content":"\u003cp\u003eThe double-slit setup was assembled from individual components to add flexibility in exploring new aspects of double-slit interference. Among these components, the \u003cem\u003eopaque strip\u003c/em\u003e (2) shown in Figs. 1A, C, and E, and a \u003cem\u003edivider\u003c/em\u003e \u003cem\u003ewall\u003c/em\u003e (3) appearing in Figs. 1B, D, and F are two alternative \u003cem\u003ebeam-splitting\u0026nbsp;\u003c/em\u003eparts of the double-slit apparatus. \u003cem\u003eSidewalls\u003c/em\u003e (4) are two opaque elements perpendicular to the beam. All settings were made with the qualitative accuracy of visual guidance, and interference patterns were also evaluated visually. A low-power laser module (Quarton VLM-650-02 LPA) was used to shine light at an opaque obstruction with two parallel slits, producing interference images on a screen located over 5 meters away. These images were photographed from the screen that was angled to stretch a fringe pattern and are displayed on top of each of the six panels of Fig. 1. An opaque strip (2) (a round steel rod 0.5 mm in diameter) was placed 40 mm from the laser exit lens, and at the center of the laser beam, Fig. 1A. A double-slit configuration was completed by installing two opaque iron sidewalls (4) on each side of the beam-splitting components, Fig. 1C and D, leaving a narrow (~0.2 mm) gap between the straight edge of each sidewall and the center part. Each gap was further adjusted to sharpen the fringe pattern. Because sidewalls (4) were mounted on separate positioners, they could be moved several centimeters along the longitudinal axis of the laser beam while maintaining a fixed distance from the beam axis, Fig. 1E. The tests in Fig. 1B, D, and E show a divider wall (3) (an iron plate of dimensions 80x13x0.5 mm) used in place of the opaque strip (2). The divider (3) was mounted against the laser lens (1) and extended 80 mm forward. The divider wall was adjusted to be precisely parallel to and at the center of the laser beam. \u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe experiment compared two beam-splitting configurations: one with an opaque strip (2) and one with a divider (3). Besides splitting the beam, the divider wall had an additional role in isolating the left half-beam from the right one over 80mm of the beam\u0026rsquo;s trajectory. Both arrangements produced similar interference patterns illustrated in Fig. 1A, C, D versus B, D, and F. Furthermore, despite moving the sidewalls from their original position (Figs 1C and D) to a new position, such as in Figs 1E and F, the corresponding patterns of fringes remained unchanged. Removing the sidewalls from the laser beam path, as in Fig. 1C and D, resulted in images in Fig. 1A and B, which are typical of an opaque strip. \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe phenomenon of light interference in a double-slit experiment is still a matter of debate [1-3, 6-8]. While interference can be explained using the classical concept of wave interference, it can also be explained within the framework of quantum mechanics. According to the latter hypothesis, a photon can interact with both slits simultaneously, which provides the rationale for single-photon interference.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOur experiment has raised questions about this scenario. We found that the pattern of fringes produced by the wall-divided slits was the same as that produced by the original double-slit setup. Also, when the components of the slit assembly were grossly misaligned, as shown in Fig. 1E and F, the interference pattern remained unaffected. Since the barrier between the two slits firmly ensures that a photon can pass only through a single slit, our experiment casts doubt on any interpretation involving simultaneous interaction with two slits, such as quantum superposition, wavefunction, or a pilot wave.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDespite its conceptual ambiguity, the double-slit experiment has proven instrumental in the development of successful quantum theory. However, certain aspects of the experiment remain in need of clarification.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003e1. Young, T.: The Bakerian lecture. Experiments and calculations relative to\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ephysical optics. Philosophical Transactions of the Royal Society of London. 94, 1-16, (1804)\u003c/p\u003e\n\u003cp\u003e2. Ronchi, V.: The Nature of Light. Cambridge: Harward University Press, (1970)\u003c/p\u003e\n\u003cp\u003e3. Ananthaswamy, A. Through Two Doors at Once: The Elegant Experiment That Captivates the Enigma of Our Quantum Reality. Duckworth, U.K. (2020)\u003c/p\u003e\n\u003cp\u003e4. Sir Geoffrey, I. T.: Interference Fringes with Feeble Light. Prof. Cam. Phil. Soc. 15, 114, (1909)\u003c/p\u003e\n\u003cp\u003e5. Ruekner, W., and Peidle, J.: Young\u0026rsquo;s double-slit experiment with single photons and quantum eraser. American Journal of Physics 81, 951-958 (2013)\u003c/p\u003e\n\u003cp\u003e6. Lewis, P.J.: Interpretations of Quantum Mechanics, Internet Encyclopedia of Philosophy.\u0026nbsp;\u003ca href=\"https://iep.utm.edu/int-qm/\"\u003ehttps://iep.utm.edu/int-qm/\u003c/a\u003e. Accessed 3 October 2023\u003c/p\u003e\n\u003cp\u003e7. Goldstein, S.: Bohmian Mechanics, Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/qm-bohm/. \u0026nbsp;(2001). Accessed 3 October 2023\u003c/p\u003e\n\u003cp\u003e8. Feinman, R. P. QED. The Strange Theory of Light and Matter. Princeton University Press (2014)\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-3425560/v2","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3425560/v2","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn a modified double-slit experiment, a laser beam is split evenly by a wall that separates the two half-beams around the slits. This setup continues to generate a standard double-slit pattern of interference. The experiment is ruling out the feasibility of interference through quantum superposition.\u003c/p\u003e","manuscriptTitle":"Quantum mechanics fails to explain double-slit photon interference.","msid":"","msnumber":"","nonDraftVersions":[{"code":2,"date":"2024-02-21 14:25:53","doi":"10.21203/rs.3.rs-3425560/v2","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}},{"code":1,"date":"2023-10-12 17:33:15","doi":"10.21203/rs.3.rs-3425560/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fb6e7df9-5f58-48f3-aed5-fac8c4489204","owner":[],"postedDate":"February 21st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":28878809,"name":"Theoretical Physics"}],"tags":[],"updatedAt":"2025-02-06T12:38:13+00:00","versionOfRecord":[],"versionCreatedAt":"2024-02-21 14:25:53","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v2","identity":"rs-3425560","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3425560","identity":"rs-3425560","version":["v2"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}