Double-slit Research Articles

Retention of a Double Slit Single Photon Interference Demonstration of Particle-Wave Duality

In the past there has been great faith in the power of laboratory activities and teacher demonstrations to enhance the learning of physics concepts. However, reviews of the effectiveness turned out to be disappointing [1-3] and have shown that lab activities and demonstrations need to be carefully designed and embedded in lessons to realize cognitive benefits [4]. Nevertheless, for secondary school quantum physics we developed a portable double slit demonstration mounted in a suitcase in which photons pass the slits approximately one by one and yet together produce an interference pattern. Based on experiences in 5 schools, we carefully designed the educational aspects of the demonstration and investigated its longterm learning effects through a written test of 68 students after 4 weeks and retention interviews after 4 months (10 interviews) and after 9 months (5 interviews). Students did remember the setup and results of the demonstration quite well. They were quite aware of the unexpected and strange wave-particle behavior of quantum particles in the demonstration including the effect of measurement or observation on the outcomes. However, half of them still had trouble defining duality in their own words and most of them did not remember de Broglie particle waves and how that related to the double slit experiment.

Concise and efficient direct-view generation of arbitrary cylindrical vector beams by a vortex half-wave plate

A concise, efficient, and practical direct-view scheme is presented to generate arbitrary cylindrical vector (CV) beams, including CV beams, vortex beams, and cylindrical vector vortex (CVV) beams, by a vortex half-wave plate (VHP). Six kinds of first-order and other high-order CV beams, such as azimuthally polarized (AP) beams, antivortex radial polarization mode beams, and three-order AP beams, are formed by simply rotating a half-wave plate. The Stokes parameters and double-slit interference of multitype CV beams are investigated in detail. The polarization parameters, including degree of polarization, polarization azimuth, and ellipticity, are obtained, which demonstrates the efficient generation of CV beams. In addition, the double-slit interference experiment is introduced in the setup, and fringe misplacement and tilt appear for CVV beams, in which the misplacement number M is 2 P + 1 for P ≤ 2 and 2 P − 1 for P ≥ 3 , where P is the polarization order number, and the fringe tilt offset is positively related to the topological charge number l of CVV beams. In addition, new types of VHPs can be formed by cascading two or more VHPs when the types of available VHPs are limited, assisting in more flexible generation of multitype CV beams. It is experimentally demonstrated that arbitrary CV beams with high quality are effectively achieved by the proposed setup, and the double-slit interference method can be utilized to determine and analyze CV beams rapidly and concisely by practical performance, which shows the potential to be implemented as a commercial device.

Atom interferometry with quantized light pulses.

The far-field patterns of atoms diffracted from a classical light field or from a quantum one in a photon-number state are identical. On the other hand, diffraction from a field in a coherent state, which shares many properties with classical light, displays a completely different behavior. We show that in contrast to the diffraction patterns, the interference signal of an atom interferometer with light-pulse beam splitters and mirrors in intense coherent states does approach the limit of classical fields. However, low photon numbers reveal the granular structure of light, leading to a reduced visibility since welcher-Weg (which-way) information is encoded into the field. We discuss this effect for a single photon-number state as well as a superposition of two such states.

Experimental Study of Bohm’s Trajectory Theory --- Comprehensive Double Slit Experiments (2)

Young’s double slit experiments, which represent the mystery of quantum mechanics, have been interpreted by quantum probability waves and by de Broglie-Bohm trajectories/pilot waves. Computer simulations of Bohm’s theory predict that (1) trajectories cannot cross, and (2) there is a triangle-shape area behind the double slit, in which there is no trajectory, i.e., no photons. In this article, we report the observations of novel comprehensive double slit experiments, which show that trajectories exist and cross in the triangular area. We show new phenomena that, in 2D cross double slit experiments and which way 2D cross double slit experiments, photons propagate along trajectories in the far field, and behave as particle and distribute as wave.

Path integral implementation of relational quantum mechanics

Relational formulation of quantum mechanics is based on the idea that relational properties among quantum systems, instead of the independent properties of a quantum system, are the most fundamental elements to construct quantum mechanics. In a recent paper (Yang in Sci Rep 8:13305, 2018), basic relational quantum mechanics framework is formulated to derive quantum probability, Born’s Rule, Schrödinger Equations, and measurement theory. This paper further extends the reformulation effort in three aspects. First, it gives a clearer explanation of the key concepts behind the framework to calculate measurement probability. Second, we provide a concrete implementation of the relational probability amplitude by extending the path integral formulation. The implementation not only clarifies the physical meaning of the relational probability amplitude, but also allows us to elegantly explain the double slit experiment, to describe the interaction history between the measured system and a series of measuring systems, and to calculate entanglement entropy based on path integral and influence functional. In return, the implementation brings back new insight to path integral itself by completing the explanation on why measurement probability can be calculated as modulus square of probability amplitude. Lastly, we clarify the connection between our reformulation and the quantum reference frame theory. A complete relational formulation of quantum mechanics needs to combine the present works with the quantum reference frame theory.

The response field and the saddle points of quantum mechanical path integrals

In quantum statistical mechanics, Moyal’s equation governs the time evolution of Wigner functions and of more general Weyl symbols that represent the density matrix of arbitrary mixed states. A formal solution to Moyal’s equation is given by Marinov’s path integral. In this paper we demonstrate that this path integral can be regarded as the natural link between several conceptual, geometric, and dynamical issues in quantum mechanics. A unifying perspective is achieved by highlighting the pivotal role which the response field, one of the integration variables in Marinov’s integral, plays for pure states even. The discussion focuses on how the integral’s semiclassical approximation relates to its strictly classical limit; unlike for Feynman type path integrals, the latter is well defined in the Marinov case. The topics covered include a random force representation of Marinov’s integral based upon the concept of “Airy averaging”, a related discussion of positivity-violating Wigner functions describing tunneling processes, and the role of the response field in maintaining quantum coherence and enabling interference phenomena. The double slit experiment for electrons and the Bohm–Aharonov effect are analyzed as illustrative examples. Furthermore, a surprising relationship between the instantons of the Marinov path integral over an analytically continued (“Wick rotated”) response field, and the complex instantons of Feynman-type integrals is found. The latter play a prominent role in recent work towards a Picard–Lefschetz theory applicable to oscillatory path integrals and the resurgence program.

النظرية النسبية الموحدة

إن النظرية النسبية العامة والخاصة تسببتا في حالة من التناقضات في علم الفيزياء. فبالرغم من أن النظرية النسبية تقدم قيماً صحيحة رياضياً، إلا أن بها قصور في العديد من الجوانب بما في ذلك التفسير النسبي لميل الجاذبية "تمدد الوقت" وانحناء أشعة الضوء على أسطح الكتل الكبيرة. وعند دراسة النظرية النسبية الخاصة نجد أنها مشتقة من تحويلات لورنتز، والتي جاءت نتيجة فشل تجربة مايكلسون مورلي. ويمكن القول بأن ما تعبر عنه تحويلات لورنتز، هو ليس المسافة الفعلية بين المشاهد والحدث. فجاءت النظرية النسبية الخاصة بمعادلات نتائجها غير دقيقة في وصف الطول والزمن والكتلة وجمع السرعات. لأن قوانين النظرية النسبية هي تطبيق تحويلات لورنتز على تلك المعادلات. لذا استوجب البحث عن تحويلات جديدة تصف المسافة الفعلية بين كل من المراقب الساكن، والمراقب المتحرك، والحدث. وأن الإلكترون هو جسيم يتحرك بواسطة موجة، وليس هو بذاته الذي يتصرف كموجة، يُمكّننا ذلك من فهم سبب سلوك الإلكترون الموجي في تجربة الشق المزدوج. اعتمدت الدراسة على التدقيق في الأسباب الضرورية اللازمة لوجود النسبية الخاصة وأصل اشتقاقها. فكانت تجربة (مايكلسون ومورلي) التي لـم يستطع العلماء تفسير نتائجها الغير متوقعة، وهي التي أدت إلى اشتقاق تحويلات (لورنتز) بهذه الصيغة الغير موفقة، والتي منها جاءت النظرية النسبية. وقد ابتكر الباحث أداة لتوضيح حركة الضوء، حيث تصف الأداة تجربة عملية لحركة الأجسام عندما تكون السرعة قريبة من سرعة الضوء. توصلت الدراسة إلى أن هناك تأثير واضح للوسط الناقل على الموجة في اتجاهها وسرعتها، والذي يمكننا من تفسير تجربة (مايكلسون ومورلي). وفي ضوء ذلك تم إيجاد تحويلات جديدة تصف المسافة والطول والزمن والسرعة بشكل صحيح. لذلك، تم وضع قوانين جديدة لتصحيح القوانين التي جاءت بها نظريات النسبية العامة والخاصة.

Psychophysical interactions with a double-slit interference pattern: Exploratory evidence of a causal influence

An experiment we conducted from 2012 to 2013, which had not been previously reported, was designed to explore possible psychophysical effects resulting from the interaction of a human mind with a quantum system. Participants focused their attention toward or away from the slits in a double-slit optical system to see if the interference pattern would be affected. Data were collected from 25 people in individual half-hour sessions; each person repeated the test ten times for a total of 250 planned sessions. “Sham” sessions designed to mimic the experimental sessions without observers present were run immediately before and after as controls. Based on the planned analysis, no evidence for a psychophysical effect was found. Because this experiment differed in two essential ways from similar, previously reported double-slit experiments, two exploratory analyses were developed, one based on a simple spectral analysis of the interference pattern and the other based on fringe visibility. For the experimental data, the outcome supported a pattern of results predicted by a causal psychophysical effect, with the spectral metric resulting in a 3.4 sigma effect (p = 0.0003), and the fringe visibility metric resulting in 7 of 22 fringes tested above 2.3 sigma after adjustment for type I error inflation, with one of those fringes at 4.3 sigma above chance (p = 0.00001). The same analyses applied to the sham data showed uniformly null outcomes. Other analyses exploring the potential that these results were due to mundane artifacts, such as fluctuations in temperature or vibration, showed no evidence of such influences. Future studies using the same protocols and analytical methods will be required to determine if these exploratory results are idiosyncratic or reflect a genuine psychophysical influence.

Leggett-Garg tests for macrorealism: Interference experiments and the simple harmonic oscillator

Leggett-Garg (LG) tests for macrorealism were originally designed to explore quantum coherence on the macroscopic scale. Interference experiments and systems modeled by harmonic oscillators provide useful examples of situations in which macroscopicity has been approached experimentally and are readily turned into LG tests for a single dichotomic variable $Q$. Applying this approach to the double-slit experiment in which a noninvasive measurement at the slits is included, we exhibit LG violations. We find that these violations are always accompanied by destructive interference. The converse is not true in general and we find that there are nontrivial regimes in which there is destructive interference but the two-time LG inequalities are satisfied, which implies that it is in fact often possible to assign (indirectly determined) probabilities for the interferometer paths. Similar features have been observed in recent work involving a LG analysis of a Mach-Zehnder interferometer and we compare with those results. We extend the analysis to the triple-slit experiment again finding LG violations, and we also exhibit examples of some surprising relationships between LG inequalities and NSIT conditions that do not exist for dichotomic variables. For the simple harmonic oscillator, we find an analytically tractable example showing a two-time LG violation with a gaussian initial state, echoing in simpler form recent results of Bose et al. [Phys. Rev. Lett. 120, 210402 (2018)].

Experimental Study of Mystery of Double Slit --- Comprehensive Double Slit Experiments

Young’s double slit experiments, which represent the mystery of quantum mechanics, have been interpreted by quantum probability waves and pilot waves. In this article, to study the mystery, we introduce the “virtual box” which represents the slide of double-slit and its right-hand neighborhood. Within, and only within, the “virtual box” the standard wave interference patterns are formed. We propose and carry out “comprehensive double slit experiments” that show that, first, light travelling from a laser source towards the slides of double slit and/or cross-double slit behaves as particle (postulate-1), and second, after leaving the zone and being directed towards the detector, the light behaves as a stream of photons (postulate-2) with no further interference due to the slits. On the one hand, the interference patterns do exist in the comprehensive-double slit experiments. On the other hand, we show four novel phenomena: (1) the fringes of the interference patterns are formed independently; (2) the fringes of the interference patterns can be formed partially; (3) the longitudinal shields do not disturb the interference patterns; and (4) the range of the virtual box is less than one inch. These novel phenomena indicate that photons behave as particles, and would not be expected if photons behave as waves created by the double slit and/or cross double slit. The comprehensive-double slit experiments show the coexistence of wave distribution and particle nature of photons in the same experiment, which violates complementarity principle and thus, seems a paradox. We suggest an interpretation to address the paradox. All observations of the comprehensive-double slit experiments are consistent. Progress in studying the mystery of the double slit experiment is presented.

Photoionization of H2+ beyond the dipole approximation with zeptosecond time resolution

We numerically simulate the photoionization of a hydrogen molecular ion exposed to a monochromatic extreme ultraviolet laser field beyond the dipole approximation. In such a diatomic system, the laser field reaches the two nuclei at different instants, adding extra phase on the ionization events from two nuclei and resulting in the shift of the angular maxima in the photoelectron momentum distribution. In the limit of the infinite internuclear distance, the double-slit interference scenario can be adopted to explain the simulated photoelectron momentum distribution. However, when the internuclear distance is as short as 1 \AA{}, the electron distributes more in the center of the molecule, and the photoelectron momentum distribution carries the single-slit diffraction character. The extracted birth time delay of photoemission from two nuclei is about a few hundred of zeptoseconds, which is similar to the experimental measurement in ${\mathrm{H}}_{2}$ [Grundmann et al., Science 370, 339 (2020)].

Sorkin parameter for type-I spontaneous parametric down-conversion biphotons and matter waves

We propose experimental measurements of the logarithmic negativity, which quantifies quantum correlations using Gouy phase measurements in an asymmetric double-slit interference experiment for twin photons. This is possible because both quantities have analogous dependence with the spatial confinement by the slits and enables one to manipulate the portion of entanglement by the Gouy phase. In order to obtain those measurements, we need to work in a regime where the position correlations between particles are strong, therefore we investigate such correlations for biphotons. Since we would like to handle entanglement quantifiers through the Gouy phase, we analyze the Gouy phase difference for two entangled photons in an asymmetric double-slit interference experiment.

Quantum Interference in Jet Substructure from Spinning Gluons.

Collimated sprays of hadrons, called jets, are an emergent phenomenon of quantum chromodynamics (QCD) at collider experiments, whose detailed internal structure encodes valuable information about the interactions of high energy quarks and gluons and their confinement into color-neutral hadrons. The flow of energy within jets is characterized by correlation functions of energy flow operators, with the three-point correlator being the first correlator with nontrivial shape dependence, playing a special role in unraveling the dynamics of QCD. In this Letter, we initiate a study of the three-point energy correlator to all orders in the strong coupling constant, in the limit where two of the detectors are squeezed together. We show that, by rotating the two squeezed detectors with respect to the third by an angle ϕ, a cos(2ϕ) dependence arising from the quantum interference between intermediate virtual gluons with +/- helicity is imprinted on the detector. This can be regarded as a double slit experiment performed with jet substructure, and it provides a direct probe of the ultimately quantum nature of the substructure of jets and of transverse spin physics in QCD. To facilitate our all-orders analysis, we adopt the operator product expansion (OPE) for light-ray operators in conformal field theory and develop it in QCD. Our application of the light-ray OPE in real world QCD establishes it as a powerful theoretical tool with broad applications for the study of jet substructure.

Quantum-inspired ensemble approach to multi-attributed and multi-agent decision-making

Decision-making is the process of selecting a belief among several other candidate beliefs. The selected belief is usually regarded as a decision while the agent that performs the decision-making process is called as a decision-maker. The decision-making process that makes use of multiple attribute cue pattern as well as multiple decision makers to select a belief is called as multi-attribute and multi-agent decision making. This research proposes quantum inspired approach to multi-attribute and multi-agent decision making process considering the ability of quantum theories to model several complex human cognitive processes as reported in the literature. The main contributions of this work are: a) quantum object based encoding of multi-attribute cue pattern b) ensemble based representation of multi-agent decision making. Further, an analogy between proposed work and double slit experiment to illustrate the interference effect in decision making is also presented. The novelty of this work lies in: a) proposing a quantum inspired ensemble approach to model multi-attribute and multi-agent decision making b) the proposed work outperforms the quantum approach as well as ensemble approach to the decision making with Pima Indiana Diabetes (PID) dataset. The proposed work yields a best accuracy of 90.5% with PID dataset.

Interference as an information-theoretic game

The double slit experiment provides a clear demarcation between classical and quantum theory, while multi-slit experiments demarcate quantum and higher-order interference theories. In this work we show that these experiments pertain to a broader class of processes, which can be formulated as information-processing tasks, providing a clear cut between classical, quantum and higher-order theories. The tasks involve two parties and communication between them with the goal of winning certain parity games. We show that the order of interference is in one-to-one correspondence with the parity order of these games. Furthermore, we prove the order of interference to be additive under composition of systems both in classical and quantum theory. The latter result can be used as a (semi)device-independent witness of the number of particles in the quantum setting. Finally, we extend our game formulation within the generalized probabilistic framework and prove that tomographic locality implies the additivity of the order of interference under composition. These results shed light on the operational meaning of the order of interference and can be important for the identification of the information-theoretic principles behind second-order interference in quantum theory.

Low Intensity Electrical Observer Effect

The study of the dual nature of the electron is proposed, with alterations in initial double-slit experiment. We are aware of mysterious nature of the quantum particles, particularly electrons. The particle behaves as wave, but upon observation, the wave-function of the electron is collapsed. No longer is an interference pattern observed, which in a sense, limits us and binds us to what we can measure and what we cannot, with current detection methods. In the double slit experiment, a source of high-intensity light is used to measure the position of the electrons, which leads to the collapse of the wave-function. An investigation is proposed to observe the effects of the low-intensity electric field on the duality of electron.

The Nature of Light: What Hidden Behind Young's Double-Slit Experiment?

The Nature of Light: What Hidden Behind Young's Double-Slit Experiment?

COMPARISON BETWEEN YOUNGS DOUBLE SLIT AND ⋀ - 𝛅 AND ⋁ - 𝛅 TYPE THREE LEVEL ATOMS PRODUCING QUANTUM INTERFERENCE

We make a comparison between the concepts and physics behind Youngs double slit experiment and ⋀-δ and ⋁-δ type three level atoms producing quantum interference.

Exploring the double-slit interference with linearly polarized photons

The linearly polarized quasi-real photons from the highly Lorentz-contracted Coulomb fields of relativistic heavy ions can fluctuate to quark-antiquark pairs, scatter off a target nucleus and emerge as vector mesons. In the process, the two colliding nuclei can switch roles to act as photon emitter or target, forming a double-slit interference pattern. The product from photoproduction inherits the photon polarization states, leading to the asymmetries of the decay angular distributions. In this letter, we study the interference effect in polarization dimension from the asymmetries of the decay angular distributions for photoprodution in heavy-ion collisions and find a periodic oscillation with the transverse momentum of vector meson, which could reasonably explain the transverse momentum dependence of the 2nd-order modulation in azimuth for the $\rho^{0}$ decay observed by the STAR collaboration.

Threshold gain of coherently coupled aperiodic lattice Y lasers.

By incorporating a holographically designed aperiodic photonic lattice within one of the arms of a Y-coupled Fabry-Perot quantum cascade laser architecture, it has been demonstrated that the multiband mode control exerted by the photonic lattice on emission spectra can, owing to the mutual optical coupling between the arms, be transferred to the second unpatterned arm. However, the underlying theoretical mechanism on how the lattice influences the threshold gain spectral properties of the Y architecture has, until now, remained unstudied. Here, we use the transfer matrix formalism, originally developed for studying aperiodic lattice lasers, to investigate this. A detailed threshold gain spectral study revealed that although the effects of facet feedback of the Y-coupled laser chip are present, due to the enhanced photonic density-of-states at user-specified frequencies, the aperiodic lattice has remarkable control over the Y architecture laser spectra, under the mutual optical coupling between the arms. Finally, indicated by the fringe patterns akin to double-slit interference, of the measured far-field beam profiles, phase-locked terahertz emissions from the Y architecture are demonstrated.