Paul Klevgard

Particles and photons appear to be total opposites; the former has rest mass which requires space to exist; the latter has kinetic energy which requires time to occur (oscillate). But they do share certain properties (e.g., quantization) that remain invariant when one is transformed (swapped) for the other. This gauge invariance is developed in some detail. The symmetry between particle and photon turns out to be one of inversion. It is the equalities of special relativity that support this inversion and the accompanying invariances: mass transformed to energy; space transformed to time. The great advantage of these symmetries (inversions) is that they provide guidance for an object little understood (the photon) based upon an object well understood (the particle). On this basis, progress can be made in the understanding of some long-standing issues: wave-particle duality, time’s arrow, the constant speed of light and nonlocality.

Radiation was a big challenge for the quantum pioneers since the photon was massless, probabilistic and appeared to be both wave and particle. Einstein’s special relativity equated mass with energy and space with time. But the equality of mass with energy, then and now, is regarded as quantitative and the equality of space with time is anything but equal; space hosts material entities; time hosts nothing. Exploring these equality issues raises some questions as to how measurable entities – particles and photons – depend upon dimensions. The particle resides in a dimension, space, while also progressing (or persisting) in a dimension, time. The photon certainly progresses in one dimension, space; does it reside there as well? These questions lead to some new conclusions regarding the nature of the photon, its dualism and its nonlocal behavior.

The photon is typically regarded as a unitary object that is both particle-discrete and wave-continuous. This is a paradoxical position and we live with it by making dualism a fundamental feature of radiation. It is argued here that the photon is not unitary; rather it has two identities, one supporting discrete behavior and the other supporting continuous (wave) behavior. There is photon kinetic energy that is always discrete/localized on arrival; it never splits (on half-silvered mirrors) or diffracts (in pinholes or slits). Then there is the photon’s probability wavefront that is continuous and diffractable. Acknowledging that the photon has two identities explains the photon’s dual nature. And wave-particle duality is central to quantum mechanics. Understanding it leads to new insights into the photon’s constant velocity and its entanglement with another photon.

The Mach-Zehnder Interferometer (MZI) is chosen to illustrate the long-standing wave-particle duality problem. Why is which-way (welcher weg) information incompatible with wave interference? How do we explain Wheeler’s delayed choice experiment? Most crucially, how can the photon divide at the first beam splitter and yet terminate on either arm with its undiminished energy? The position advanced is that the photon has two identities, one supporting particle features and the other wave features. There is photon kinetic energy that never splits (on half-silvered mirrors) or diffracts (in pinholes or slits). Then there are photon probability waves that do diffract and can reinforce or cancel. Photon kinetic energy is oscillatory; its cycles require/occupy time. E = mc2 suggests that kinetic energy is physically real as occurrence in time just as rest mass is physically real as existence in space; both are quantized and both occupy/require a dimension for their occurrence or existence. Photon kinetic energy (KE) thus resides in time, but is still present/available for interactions (events) in space; rest mass (e.g., your desk) resides in space but is still present/available for interactions (events) in time. While photon probability waves progress in space and diffract there, photon KE resides in time and never diffracts in space; at reception it always arrives whole and imitates particle impact without being a particle. Photon probability waves are real; they diffract in space. Acknowledging that the photon has two identities (residing energy and progressing probability), explains photon dual nature. And wave-particle duality is central to quantum mechanics. Understanding it leads to new insights into entanglement, nonlocality and the measurement problem. A 30-minute video on nonlocality and photon dualism can be found by a google: search “youtube klevgard nonlocality”)

Photons deliver their energy and momentum to a point on a material target. It is commonplace to attribute this to particle impact. But since the in-flight photon also has a wave nature, we are stuck with the paradox of wave-particle duality. It is argued here that the photon’s wave nature is indisputable, but its particle nature is open to question. Photons deliver energy. The problem with invoking impact as a means of delivery is that energy becomes a payload which in turn requires a particle. This assumes that energy is always a payload and there is but one mode of energy delivery; surely two unsupported assumptions. It should be possible to explain photon termination without invoking particle impact. One approach offered here is to question the assumption that the photon is a unitary object. Perhaps the photon has two linked-but-distinct identities: one supporting wave behavior and the other supporting discrete behavior. It is the latter that might imitate particle impact.

We think of kinetic energy (KE) as a quantity possessed by rest mass in motion. But somehow electromagnetic (EM) radiation transports KE across space without any rest mass. In addition, a single photon passing through a double slit diffracts into multiple paths in space without affecting its KE. This is hard to explain. Quantum theories that confront the double slit problem do not address these two issues directly. The ontology of radiation KE is examined which leads to some new ideas as to the nature of KE transmission by radiation.

Part I looks at duality for the photon; Part II does the same for the electron. The traditional division of kinetic energy between radiation and matter-in-motion is reexamined permitting new insights into duality. An in-flight photon displays wave characteristics. Such a photon can interfere with itself and take all available space paths as a wave. In addition, photons pass through one another like waves whereas particles impact each other. It is only when the photon terminates on a material object and gives up its energy – and ceases to be a photon – that particle characteristics appear, namely: 1) the photon is finally space located; and 2) oscillation ceases. This suggests that the photon’s wave and particle nature do not overlap. Understanding photon termination as a release of mass stored, rather than particle impact, permits a better understanding of presumed wave-particle duality for the photon.

The classical concept of projectile motion underwent a series of seemingly minor changes and adjustments between Planck’s quantum discovery and Dirac’s early codification of quantum theory. The goal of physicists in this period was to keep change to a minimum and preserve as much as possible of the traditional projectile paradigm. These adjustments were successful in masking an all-out projectile paradigm crisis, but they have left us with a conceptual muddle. This has been especially deleterious for special relativity and our understanding of space contraction and time dilation.

Pure entities consist of mass or energy without the presence of the other: the inertial rest mass is all mass and no kinetic energy ; the photon is all kinetic energy and no mass. Pure entities may be compared at the ontological level. From this analysis it is shown that Einstein’s second postulate of special relativity is actually derivative from a more fundamental attribute of all pure entities. Part two of this essay focuses on the space contraction and time dilation of moving physical objects. Arguments against attributing these changes to space and time itself are offered. Instead, the roles of kinetic energy and of de Broglie wave effects are presented as a better explanation.