Abstract An interferometer in which all of its components are treated as quantum bodies is examined with the standard interpretation and with a model in which its uncoupled spatially separated components act collectively. These models utilize superposition principles that differ when applied to systems composed of three or more bodies. Interferometric discrepancies between these models that involve frequency shifts and recoil are shown to be difficult to measure. More pronounced differences involve quantum correlated interference. The collective model provides a missing connection between quantum and semiclassical theories. Scattering from an entangled state, which cannot be divided into disjoint parts, is proposed to involve such collective recoil. Collective scattering offers a viable supplement to the standard model, thereby providing insight into constructing tests of the superposition principle in systems with three or more bodies.
Abstract An interferometer in which all of its components are treated as quantum bodies is examined with the standard interpretation and with a model in which its uncoupled spatially separated components act collectively. These models utilize superposition principles that differ when applied to systems composed of three or more bodies. Interferometric discrepancies between these models that involve frequency shifts and recoil are shown to be difficult to measure. More pronounced differences involve quantum correlated interference. The collective model provides a missing connection between quantum and semiclassical theories. Scattering from an entangled state, which cannot be divided into disjoint parts, is proposed to involve such collective recoil. Collective scattering offers a viable supplement to the standard model, thereby providing insight into constructing tests of the superposition principle in systems with three or more bodies.
Abstract Exploring many-body interactions in an inquiry-based environment can enhance undergraduate and graduate student understanding of quantum physics. Specific classroom examples are provided in increasing complexity of content and maturity of comprehension. The simplest example of a purely quantum system (without using a classical potential) involves the many-body treatment of two quantum objects reflecting from each other via hard-sphere scattering in one dimensional motion. This example is extended to a particle confined in an infinite square well or interacting with a finite barrier and finite well where each of the objects generating the potentials now recoils due to reflection of the particle. These simple systems introduce concepts of entanglement, quantum correlated interference, and measurements made on a subset of the bodies. Completely inelastic scattering that involves the fusing (or destruction) of two bodies into the creation of a third is also discussed. In addition to this content, guided inquiry-based pedagogy is illustrated using two examples: collective recoil when a particle reflects from two scatterers and measurements on each body made asynchronously. The examples provided explore potential methods to verify quantum effects on a macroscopic scale and address measurement in a quantum system.
Entanglement and interference are both hallmark effects of quantum physics. Particularly rich dynamics arise when multiple (at least partially) indistinguishable particles are subjected to either of these phenomena. By combining both entanglement and many-particle interference, we propose an interferometric setting through which N -particle interference can be observed, while any interference of lower orders is strictly suppressed. We experimentally demonstrate this effect in a four-photon interferometer, where the interference is nonlocal, in principle, as only pairs of photons interfere at two separate and independent beam splitters. A joint detection of all four photons identifies a high-visibility interference pattern varying as a function of their collective four-particle phase, a genuine four-body property.
Abstract Correlated interference is calculated for a microscopic particle retro‐reflecting from two spatially separated scatterers that are free to move, all three of which are treated as quantum bodies: the positions of the particle traversing this 1D interferometer and those of the interferometer components are all uncertain. Interference in a measurement of only the particle is shown to disappear for microscopic yet appear for mesoscopic scatterers, contrary to that of a quantum‐classical transition. A measurement of this threshold can verify quantum correlations in many‐body systems by measuring only the retro‐reflected microscopic particle. The decoherence of a mesoscopic scatterer is determined by this threshold without it having to traverse slits or beamsplitters.
Abstract Quantum interference plays a central role in the realm of quantum particles, revealing their wave‐like nature and probabilistic behavior. It relies on the concept of superposition, where the probability amplitudes of different processes that contribute to the given phenomenon interfere with each other. When combined, their phases can interfere either constructively or destructively. Quantum interference manifests in three distinct forms: optical interference, arising from the interaction of light waves and forming the basis for technologies such as lasers and optical filters; interference via atoms, which involves manipulating atomic states to control light–matter interactions and enables techniques like Stimulated Raman Adiabatic Passage and Electromagnetically Induced Transparency in quantum information processing; and interference of atoms with themselves, in which the matter waves of single atoms interfere with each other, as employed in precision measurements such as atom interferometry–a crucial tool for applications in quantum mechanics and precision navigation. These diverse forms of quantum interference have profound implications for numerous scientific disciplines, demonstrating that interference can involve particles beyond just photons.
Abstract This paper presents a fundamental re-examination of quantum entanglement, nonlocality, and the limits of standard quantum mechanics by introducing a new theoretical framework: No-Signal Control Theory (NSC theory).The approach proposes that a quantum state cannot be fully described within a conventional single-layer Hilbert space. Instead, it must be formulated within a two-layer Hilbert-space structure, consisting of: an observable layer, and a structural layer. This two-layer Hilbert space model provides a unified explanation for several reproducible IBM Quantum device experiments that challenge standard interpretations of quantum mechanics. These experimentally confirmed and highly repeatable effects include: Nonlocal Hadamard switching: the H-gate changes a remote qubit’s measurement probability (from 0→1/2 or 1→1/2), acting as a nonlocal structural switch without transmitting classical information. CNOT order dependence: the measurement distribution shifts significantly depending on whether the control and target qubits are swapped, indicating a structural asymmetry not accounted for by standard quantum theory. NS/EW basis stability asymmetry: distinct stability differences between the north–south (NS) and east–west (EW) basis states, demonstrating the presence of a hidden structural layer. Collectively, these results suggest that remote operations do not transmit information but do transmit structure, preserving compatibility with the no-signaling principle while revealing a deeper mechanism behind nonlocal quantum behavior.This also connects directly to the proposed PQ (Perception Quantum) Unified Model, which interprets quantum tunneling, CNOT asymmetry, and structural recoil within the same two-layer framework. [Supplementary Material] Title: Visual Guide to NSC Theory and the PQ Hypothesis This supplementary document provides a visual and geometric interpretation of the proposed Two-Story Quantum Structure, complementing the theoretical and experimental results presented in the main paper. Key Contents: Visualization of the Two-Layer Structure:Diagrammatic representations of the Observation Layer (“Window”) and the Structure Layer (“Arrow”). Physical Interpretation of Quantum Gates:How the Hadamard (H) gate rotates the observation layer, and how the CNOT gate copies structural directionality, creating asymmetric recoil effects. Mechanism of Recoil & Tunneling:Intuitive diagrams explaining the “structural recoil” in asymmetric CNOT operations and the time-reversal interpretation of quantum tunneling within the PQ unified framework. This guide is intended to help researchers intuitively understand the physical mechanisms underlying NSC theory, PQ theory, and the proposed two-layer Hilbert-space formulation of quantum mechanics.[Update: November 29, 2025] Added Supplementary Material B: Provides Python source code and experimental records verifying the Nonlocal Structural Switching and Resonance via IBM Quantum hardware. This serves as experimental proof of the NSC Theory.
In quantum mechanics it is well known that, if any two states are superposed, they interfere with each other. It is true, we should not deny such interference in principle, but we may assert what follows. When two states different from each other in a great many degrees of freedom are superposed, the interference effect becomes obscure. If they are different in an infinitely many degrees of freedom, they do not interfere at all, and their superposition is nothing but a mere probability function. This assertion enables us to understand how the probability amplitude for a micro-system is converted into a probability function for a measuring apparatus in the cource of measurement.