Testing Born’s Rule in Quantum Mechanics for Three Mutually Exclusive Events (original) (raw)
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Testing Born’s Rule in Quantum Mechanics with a Triple Slit Experiment
AIP Conference Proceedings, 2009
In Mod. Phys. Lett. A 9, 3119 (1994), one of us (R.D.S) investigated a formulation of quantum mechanics as a generalized measure theory. Quantum mechanics computes probabilities from the absolute squares of complex amplitudes, and the resulting interference violates the (Kolmogorov) sum rule expressing the additivity of probabilities of mutually exclusive events. However, there is a higher order sum rule that quantum mechanics does obey, involving the probabilities of three mutually exclusive possibilities. We could imagine a yet more general theory by assuming that it violates the next higher sum rule. In this paper, we report results from an ongoing experiment that sets out to test the validity of this second sum rule by measuring the interference patterns produced by three slits and all the possible combinations of those slits being open or closed. We use attenuated laser light combined with single photon counting to confirm the particle character of the measured light.
Ruling Out Multi-Order Interference in Quantum Mechanics
Science, 2010
Quantum mechanics and gravitation are two pillars of modern physics. Despite their success in describing the physical world around us, they seem to be incompatible theories. There are suggestions that one of these theories must be generalized to achieve unification. For example, Born's rule, one of the axioms of quantum mechanics could be violated. Born's rule predicts that quantum interference, as shown by a double slit diffraction experiment, occurs from pairs of paths. A generalized version of quantum mechanics might allow multi-path, i.e. higher order interferences thus leading to a deviation from the theory. We performed a three slit experiment with photons and bounded the magnitude of three path interference to less than 10 -2 of the expected twopath interference, thus ruling out third and higher order interference and providing a bound on the accuracy of Born's rule. Our experiment is consistent with the postulate both in semi-classical and quantum regimes.
Counterexample to the Born Rule
In this article we examine the data of a 1986 experiment by Aspect, Grangier and Roger involving correlated pairs of photons in which one of each pair passes through a MachZehnder interferometer. It is shown that the Born Rule for calculating the probability of detection on one part of the multiparticle system does not predict the experimental results. In particular, the Born Rule predicts no variation in detection probability vs. relative phase between photons of either arm, a contradiction. A modification to the Born Rule is then proposed, which is shown to give the correct results.
2022
The quantum superposition principle implies that a particle entering an interferometer evolves by simultaneously taking both arms. If a non-destructive, minimally-disturbing interaction coupling a particle property to a pointer is implemented on each arm while maintaining the path superposition, quantum theory predicts that, for a fixed state measured at the output port, certain particle properties can be associated with only one or the other path. Here we report realization of this prediction through joint observation of the spatial and polarization degrees of freedom of a single photon in the two arms of an interferometer. Significant pointer shifts ($\sim$50 microns) are observed in each arm. This observation, involving coupling distinct properties of a quantum system in spatially separated regions, opens new possibilities for quantum information protocols and for tests of quantumness for mesoscopic systems.
The Magical "Born Rule" and Quantum "Measurement": Implications for Physics
Foundations, 2023
I. The arena of quantum mechanics and quantum field theory is the abstract, unobserved and unobservable, M-dimensional formal Hilbert space ≠ spacetime. II. The arena of observations—and, more generally, of all events (i.e., everything) in the real physical world—is the classical four-dimensional physical spacetime. III. The “Born rule” is the random process “magically” transforming I into II. Wavefunctions are superposed and entangled only in the abstract space I, never in spacetime II. Attempted formulations of quantum theory directly in real physical spacetime actually constitute examples of “locally real” theories, as defined by Clauser and Horne, and are therefore already empirically refuted by the numerous tests of Bell’s theorem in real, controlled experiments in laboratories here on Earth. Observed quantum entities (i.e., events) are never superposed or entangled as they: (1) exclusively “live” (manifest) in real physical spacetime and (2) are not described by entangled wavefunctions after “measurement” effectuated by III. When separated and treated correctly in this way, a number of fundamental problems and “paradoxes” of quantum theory vs. relativity (i.e., spacetime) simply vanish, such as the black hole information paradox, the infinite zero-point energy of quantum field theory and the quantization of general relativity.
Which-way double-slit experiments and Born-rule violation
Physical Review A
In which-way double-slit experiments with perfect detectors, it is assumed that having a second detector at the slits is redundant, as it will not change the interference pattern. We however show that if higher-order or non-classical paths are accounted for, the presence of the second detector will have an effect on the interference pattern. Accounting for these non-classical paths also means that the Sorkin parameter in triple-slit experiments is only an approximate measure of Born rule violation. Using the difference between single and double which-way detectors, we give an alternative parameter which is an exact measure of Born rule violation.
The magical "Born Rule" & quantum "measurement": Implications for Physics
The magical ``Born Rule" & quantum ``measurement": Implications for Physics, 2023
I. The arena of quantum mechanics and quantum field theory is the abstract, unobserved and unobservable, M-dimensional formal Hilbert space = spacetime. II. The arena of observations and, more generally, of all events (i.e. everything) in the real physical world, is the classical 4-dimensional physical spacetime. III. The "Born Rule" is the random process "magically" transforming I. into II. Wavefunctions are superposed and entangled only in the abstract space I., never in spacetime II. Attempted formulations of quantum theory directly in real physical spacetime actually constitute examples of "locally real" theories, as defined by Clauser & Horne, and are therefore already empirically refuted by the numerous tests of Bell's theorem in real, controlled experiments in laboratories here on Earth. Observed quantum entities, i.e. events, are never superposed or entangled as they: 1) Exclusively "live" (manifest) in real physical spacetime, 2) Are not described by entangled wavefunctions after "measurement", effectuated by III. When separated and treated correctly in this way, a number of fundamental problems and "paradoxes" of quantum theory vs. relativity (i.e. spacetime) simply vanish, such as the black hole information paradox, infinite zero-point energy of quantum field theory and quantization of general relativity.
Quantum probabilities from quantum entanglement: experimentally unpacking the Born rule
New Journal of Physics, 2016
The Born rule, a foundational axiom used to deduce probabilities of events from wavefunctions, is indispensable in the everyday practice of quantum physics. It is also key in the quest to reconcile the ostensibly inconsistent laws of the quantum and classical realms, as it confers physical significance to reduced density matrices, the essential tools of decoherence theory. Following Bohr's Copenhagen interpretation, textbooks postulate the Born rule outright. However, recent attempts to derive it from other quantum principles have been successful, holding promise for simplifying and clarifying the quantum foundational bedrock. A major family of derivations is based on envariance, a recently discovered symmetry of entangled quantum states. Here, we identify and experimentally test three premises central to these envariance-based derivations, thus demonstrating, in the microworld, the symmetries from which the Born rule is derived. Further, we demonstrate envariance in a purely local quantum system, showing its independence from relativistic causality.
A new 'wave-particle non-dualistic interpretation of quantum mechanics at a single-quantum level' is presented by interpreting the Schrödinger wave function as an 'instantaneous resonant spatial mode' (IRSM) to which a quantum is confined and moves akin to the case of a test particle in the curved space-time of the general theory of relativity. This union of the wave and particle natures into a single entity is termed as non-duality. Using quantum formalism, the IRSM is shown to induce dual-vectors at the boundaries and interacts according to the inner-product. The overall phase associated with the state vector, which never contributes to the inner-product, is related to a particular eigenstate of an observable where the particle resides. This eigenstate becomes the natural outcome during observation of a single-quantum's single event. Observation over a large number of identical quanta, differing only by overall phases, results in the relative frequency of detection which yields Born's rule as a limiting case proving the absence of measurement problem in quantum mechanics. The non-duality not only provides the actual mechanism for the 'wave function collapse' but also statistically becomes equivalent to the Copenhagen interpretation. An explicit derivation for the Born rule using individual quantum events is provided by considering an example of spin-1/2 particles in the Stern-Gerlach experiment. In this regard, a generalized representation for the SU (2) algebra, facilitating the description of single-quantum events, is constructed without any deviations from the quantum formalism.
Two-photon interferometry illuminates quantum measurements
2013
The quantum measurement problem still finds no consensus. Nonlocal interferometry provides an unprecedented experimental probe by entangling two photons in the "measurement state" (MS). The experiments show that each photon "measures" the other; the resulting entanglement decoheres both photons; decoherence collapses both photons to unpredictable but definite outcomes; and the two-photon MS continues evolving coherently. Thus, contrary to common opinion, when a two-part system is in the MS, the outcomes actually observed at both subsystems are definite. Although standard quantum physics postulates definite outcomes, two-photon interferometry verifies them to be not only consistent with, but actually a prediction of, the other principles. Nonlocality is the key to understanding this. As a consequence of nonlocality, the states we actually observe are the local states. These actually-observed local states collapse, while the global MS, which can be "observed" only after the fact by collecting coincidence data from both subsystems, continues its unitary evolution. This conclusion implies a refined understanding of the eigenstate principle: Following a measurement, the actually-observed local state instantly jumps into the observed eigenstate. Various experts' objections are rebutted.