The paper explores the fundamental physical principles of quantum mechanics (in fact, quantum field theory) that limit the bit rate for long distances and examines the assumption used in this exploration that losses can be ignored. Propagation of photons in optical fibers is modelled using methods of quantum electrodynamics. We define the “photon duration” as the standard deviation of the photon arrival time; we find its asymptotics for long distances and then obtain the main result of the paper: (...) the linear dependence of photon duration on the distance when losses can be ignored. This effect puts the limit to joint increasing of the photon flux and the distance from the source and it has consequences for quantum communication. Once quantum communication develops into a real technology (including essential decrease of losses in optical fibres), it would be appealing to engineers to increase both the photon flux and the distance. And here our “photon flux/distance effect” has to be taken into account. This effect also may set an additional constraint to the performance of a loophole free test of Bell’s type—to close jointly the detection and locality loopholes. (shrink)

Photonic Crystals is the first book to address one of the newest and most exciting developments in physics--the discovery of photonic band-gap materials and their use in controlling the propagation of light. Recent discoveries show that many of the properties of an electron in a semiconductor crystal can apply to a particle of light in a photonic crystal. This has vast implications for physicists, materials scientists, and electrical engineers and suggests such possible developments as an entirely optical computer. Combining cutting-edge (...) research with the basic theoretical concepts behind photonic crystals, the authors present to undergraduates and researchers a concise, readable, and comprehensive text on these novel materials and their applications. The first chapters develop the theoretical tools of photonic crystals in a broad, intuitive fashion, starting from nothing more than Maxwell's equations and Fourier analysis, and include analogies to traditional solid-state physics and quantum theory. There follows an investigation of the unique phenomena that take place within photonic crystals, at defect sites, and at surfaces and interfaces. The authors offer a new treatment of the traditional multilayer film (a one-dimensional photonic crystal), which allows for the extension to higher dimensions and more complex geometries. After exploring the capabilities of photonic crystals to guide and localize light, the authors demonstrate how these notions can be put to work. (shrink)

This book focuses on the gradual formation of the concept of ‘light quanta’ or ‘photons’, as they have usually been called in English since 1926. The great number of synonyms that have been used by physicists to denote this concept indicates that there are many different mental models of what ‘light quanta’ are: simply finite, ‘quantized packages of energy’ or ‘bullets of light’? ‘Atoms of light’ or ‘molecules of light’? ‘Light corpuscles’ or ‘quantized waves’? Singularities of the field or spatially (...) extended structures able to interfere? ‘Photons’ in G.N. Lewis’s sense, or as defined by QED, i.e. virtual exchange particles transmitting the electromagnetic force? The term ‘light quantum’ made its first appearance in Albert Einstein’s 1905 paper on a “heuristic point of view” to cope with the photoelectric effect and other forms of interaction of light and matter, but the mental model associated with it has a rich history both before and after 1905. Some of its semantic layers go as far back as Newton and Kepler, some are only fully expressed several decades later, while others initially increased in importance then diminished and finally vanished. In conjunction with these various terms, several mental models of light quanta were developed—six of them are explored more closely in this book. It discusses two historiographic approaches to the problem of concept formation: the author’s own model of conceptual development as a series of semantic accretions and Mark Turner’s model of ‘conceptual blending’. Both of these models are shown to be useful and should be explored further. This is the first historiographically sophisticated history of the fully fledged concept and all of its twelve semantic layers. It systematically combines the history of science with the history of terms and a philosophically inspired history of ideas in conjunction with insights from cognitive science. (shrink)

In this paper, we will review research done by the Large-Scale Integrated Photonics group at HP Laboratories, and in particular we will discuss applications of optical resonances in dielectric microstructures and nanostructures to future classical and quantum information technologies. Our goal is to scale photonic technologies over the next decade in much the same way as electronics over the past five, thereby establishing a Moore’s Law for optics.

The question of the relation between the amplitude of the photon vector potential and its angular frequency is analyzed. The analogy between the relativistic quantum mechanical equations for a massles particle and those governing the photon vector potential appears clearly. Finally, the virtual electromagnetic waves associated with the photon and predicted by de Broglie, Bohr, and other appear naturally as a result of the photon vector potential quantification.

Femtosecond laser microfabrication has emerged in the last decade as a powerful technique for direct inscription of low loss optical waveguides in practically any transparent dielectric substrate, showing outstanding versatility. Prototyping of new devices is made rapid, cheap and easy: optical circuits are written directly buried in the substrate, using the laser beam as an optical pen, without any need of costly masks as required by conventional photolithography. Many proof-of-principle demonstrations of integrated optics can be obtained, including splitters, directional couplers, (...) and Mach–Zehnder interferometers. Actually, the road towards applications has just been opened, and the unique capabilities of femtosecond laser micromachining will enable achievements inconceivable with other technologies. In this work, the femtosecond laser fabrication technique is discussed, together with its application to the realization of integrated photonic quantum circuits. (shrink)

Tunneling oscillations induced in a double quantum well by a monochromatic electromagnetic wave incident perpendicularly to the plane of the well, and polarized along the direction of its growth, are treated. For the wave frequency in proximity to the energy difference between two states of opposite symmetry, a periodic energy exchange between the wave and a carrier which moves from one energy state to the other is established. When the carrier starts from the low energy level it borrows energy from (...) the wave until it reaches the higher energy state. On its way the carrier performs current oscillations that cease whenever it reaches an eigenstate. Similarly, oscillation is required during the carrier's motion from the high to the low energy state for the photon emission in order that the radiation gets back the energy already given to the carrier. Thus an accelerating charge not only radiates, but also absorbs wave energy. When there prevails a considerable population difference between the two levels the possibility of quantum beat exits. (shrink)

This textbook on vision reflects the integrated computational approach of modern research scientists, combining psychological, computational and neuroscientific perspectives.

Albert Einstein taught us that c, the speed of light in vacuum, is nature's ultimate speed limit, the highest speed at which matter, energy, and information can travel through space-time. In several AV columns I've discussed ways for getting around this annoying natural law, the law that SF writers and fans most wish to violate. Two AV columns discussed the possibility of getting around the lightspeed limit by popping through a trans-spatial wormhole shortcut. See [ Analog-6-89, "Wormholes and Time Machines"] (...) and [Analog-5-90, "Wormholes II: Getting There in No Time"]. Two others discussed the possible use the faster-than-light nonlocal handshaking implicit in quantum mechanics for FTL messages and travel. See [Analog-11-86, "The Quantum Handshake"] and [Analog-9-88, "Paradoxes and FTL Communication"]. Both of those methods, however, are beyond our present technology, and the latter is probably impossible. (shrink)

A macroscopic realization of the peculiar virtual particles is presented. The classical Helmholtz and the Schrödinger equations are differential equations of the same mathematical structure. The solutions with an imaginary wave number are called evanescent modes in the case of elastic and electromagnetic fields. In the case of non-relativistic quantum mechanical fields they are called tunneling solutions. The imaginary wave numbers point to strange consequences: The waves are non-local, they are not observable, and they are described as virtual particles. During (...) the last two decades QED calculations of the solutions with an imaginary wave number have been experimentally confirmed for phonons, photons, and electrons. The experimental proofs of the predictions of non-relativistic quantum mechanics and the Wigner phase time approach for the elastic, electromagnetic and Schrödinger fields will be presented in this article. The results are zero time in the barrier and an interaction time (i.e. a phase shift) at the barrier interfaces. The measured tunneling time scales approximately inversely with the particle energy. Actually, the tunneling time is given only by the barrier boundary interaction time, as zero time is spent inside a barrier. (shrink)

Based on neurobiological data, modern concepts of self-organization and a careful rationale, the hypothesis is put forward that the fleeting, highly ordered patterns of electric and/or magnetic fields, generated by assemblies of dendritic trees of specialized neuronal networks, should be thought of as the end-product of chaotic, dynamically governed self-organization. Such patterns encode for subjective experiences such as pain and pleasure, or perceiving colours. Because by quantum mechanical definition virtual photons are the theoretical constituents of electric and magnetic fields, the (...) former hypothesis can be re-formulated as follows: it is the highly ordered patterns of virtual photons that encode for subjective experiences. Arguments are then given that consciousness did not emerge during evolution only after neuronal networks had been formed able to generate electric and/or magnetic fields of sufficient complexity but, rather, that subjectivity already existed in a very elementary form as a fundamental property of the omnipresent virtual photons, i.e., of matter. The contribution of neuronal networks to consciousness was to generate highly ordered patterns of germs of subjectivity , so allowing complex subjective experiences. Due to the omnipresence of virtual photons, it follows finally that the whole universe must be imbued with subjectivity. An experimental strategy is proposed to test the hypothesis. (shrink)

This chapter discusses seven of nine and the doctor experience various ups and downs as they navigate the deepest reaches of social and emotional interactions. Conscious experiences have two basic components: the experience itself and the meaning you derive from it, what it means to you. Husserl used two Greek terms, noesis and noema, to explain these aspects. Noesis gives meaning to an experience, as opposed to simply dismissing everyday occurrence as just “things” that happen without any intention or influence. (...) Husserl goes as far as to say that the noesis becomes the “real content” of the experience. In contrast, the noema is the actual meaning of the experience: its point about something, so that the events that happen to us make sense to us in terms of generating personal significance. Husserl distinguishes between the content of an act, what makes an experience meaningful or intentional from its object. (shrink)

An experiment designed to test the highly speculative hypothesis of photon consciousness was executed. It was found that, within the accuracy attainable with the apparatus, there is no empirical justification for the hypothesis.

Starting from the phase space representation of quantum mechanics we provide an Euclidean system of covariance for the photon. In particular, we consider systems with the Poincaré group as the symmetry group and use a standard procedure in order to build a phase space and a localization observable on the phase space. Then we focus on the massless representations of the Poincaré group that we use to build a space localization observable for the photon.

This paper takes as its point of departure recent research into the possibility that human beings can perceive single photons. In order to appreciate what quantum perception may entail, we first explore several of the leading interpretations of quantum mechanics, then consider an alternative view based on the ontological phenomenology of Maurice Merleau-Ponty and Martin Heidegger. Next, the philosophical analysis is brought into sharper focus by employing a perceptual model, the Necker cube, augmented by the topology of the Klein bottle. (...) This paves the way for addressing in greater depth the paper’s central question: Just what would it take to observe the quantum reality of the photon? In formulating an answer, we examine the nature of scientific objectivity itself, along with the paradoxical properties of light. The conclusion reached is that quantum perception requires a new kind of observation, one in which the observer of the photon adopts a concretely self-reflexive observational posture that brings her into close ontological relationship with the observed. (shrink)

The paper contains a discussion on two kinds of coincidence experiments. First, a standard two-photon coincidence experiment is considered and it is shown that its outcomes are incompatible with any classical radiation theory because of the role of the state vector reduction phenomenon in such an experiment. In the second part of the paper a proposed new kind of photon coincidence experiment is discussed. The classical and quantum predictions for the outcomes of this experiment differ dramatically and therefore (...) the experiment should constitute a new limitation to the classical radiation theories. The proposed experiment should also yield information about the kinematics of the reduction of the state vector process. (shrink)

In a recent paper, Schlegel states “... the photon clock when interpreted as a device for showing the Lorentz transformation of time does actually involve a violation of basic relativity principles.” His conclusion is false, and is based on an incorrect analysis of the photon clock in two reference frames with relative motion. The purpose of this note is to present a corrected analysis and show that such an analysis is consistent with basic relativity principles.

Mathematics from the electromagnetic field quantization procedure and the soliton models of photons are used to construct a new 3D model of photons. Besides the interaction potential between the charged particle and the photons, which contains the annihilation and creation operators of photons, the new function for a description of free propagating photons is derived. This function presents the vector potential of the field, the function is a product of the harmonic oscillator eigenfunction with the well-defined coordinate of the oscillator (...) and the Gaussian function of the polar radius in the transverse direction. In the article, the difference between the quantum mechanics of particles and photons is discussed. (shrink)

The extended Church-Turing thesis posits that any computable function can be calculated efficiently by a probabilistic Turing machine. If this thesis held true, the global effort to build quantum computers might ultimately be unnecessary. The thesis would however be strongly contradicted by a physical device that efficiently performs a task believed to be intractable for classical computers. BosonSampling - the sampling from a distribution of n photons undergoing some linear-optical process - is a recently developed, and experimentally accessible example of (...) such a task [1]. (shrink)

Two widely different conceptions of electromagnetic radiation were compared by Einstein in his 1916 papers, namely, the classically diffuse form and the fully directional form. The emission process of each kind of radiation is examined hereafter from a relativistic point of view. The necessary covariance of any physical description, further specifying the original directional property, points to a strictly quantized form of radiation as the only one consistent with relativity, thus showing a deep relationship between this latter and quantum theory.

Examining the process of action at a distance, we arrive at the following conclusions: (a) The virtual photons and mesons transmitting Coulomb and nuclear forces, respectively, do not arise from “temporary violations of energy conservation,” but, on the contrary, exactly embody the potential energy corresponding to the relevant forceF that they transmit on their collision with the charged particles or nucleons via the formula Δp=FΔt. (b) In the case of an attractive force, the energy of these photons and mesons is (...) negative. The way this comes about is made clear by a more detailed investigation of Feynman's notion of “traveling backward in time.” (c) The action corresponding to, e.g., a virtual photon's appearance is exactly one quantumh, which fact is responsible for the unobservability of such photons. Some consequences of the revised conception of potential energy for, e.g., the tunnel and the Bohm-Aharonov effect are mentioned. (shrink)

In contrast to the Nietzschean conception of Übermensch as signifying, hitherto, a supermanhood in moral terms alone, the principle of the latter lies in its being antithetical to the present human status, and in its thus proving altogether superior both ontologically and physically. With this premise the notions of Sixth Force and Photonic Frame are now associated. Set forth after a qualitative fashion, while the former is related to the thus far known elemental constituents of matter, as well as to (...) forces and interactions between matter particles, and under this form deemed to intangibly account for all the chaos, indeterminacy and otherwise imperfection or limit found so peculiar to man, the latter refers to an ultimate trait in the actual Overman touching a most luminous and unparalleled corporeality. An original conception of geometry in photonic terms is also propounded. Illustrations meeting at length with a semiotic process and literary hints add to the suggestion. (shrink)

The Maxwell equations are shown to be the one-photon spin-one quantum equations. All Maxwell equations (without sources) are derived simultaneously from first principles, similar to those which have been used to derive the Dirac relativistic electron equation. The wavefunction is a linear combination of the electric and magnetic fields. The procedure is not unique, there are ambiguities of adding a scalar field. A quaternionic representation of the Maxwell equations (with sources) is constructed, a covariant reformulation of which is presented. (...) Whittaker potentials are analysed. Conservation laws are derived using a method of “pseudo-Lagrangians.”. (shrink)

Arguments are provided for the reality of the quantum vacuum fields. A polarization correlation experiment with two maximally entangled photons created by spontaneous parametric down-conversion is studied in the Weyl–Wigner formalism, that reproduces the quantum predictions. An interpretation is proposed in terms of stochastic processes assuming that the quantum vacuum fields are real. This proves that local realism is compatible with a violation of Bell inequalities, thus rebutting the claim that it has been refuted by experiments. Entanglement appears as a (...) correlation between fluctuations of a signal field and vacuum fields. (shrink)

Some interference experiments with the photon pairs from two parametric down-converters are described and analyzed. They are found to contribute to the interpretation of the quantum state.

The traditional approach to light amplification is shown to be based on the idea that photons of the incoming beam act as independent particles. If atomic stimulation is instead attributed to the action of the wave, a different photon distribution is obtained in the final state. The new distribution turns out to be Poissonian, in agreement with some experimental evidence. The expected rate of coincidences for an empty-wave amplification experiment is calculated, and found up to 30% higher than obtained (...) from the traditional approach. (shrink)

A nontechnical review is given of a topological bootstrap theory, with emphasis on theraison d'être for an electromagnetism whose fine-structure constant is of order10 −2.

Reasons for taking1/2h/c 2 in cgs units as an equivalent in grams for the photon “rest mass” are given. Its numerical value of3.68×10 −48 g corresponds to the minimum mass equivalent energy for one half-cycle of an electromagnetic dipole field distribution, which is discontinuous. For the fluid models that are discussed, this field distribution corresponds somewhat to a hydrodynamic toroidal vortex which is stationary—if we use toroidal coordinates and assume that the ring origin has the radial velocity c, that (...) the gauge is defined by the ring origin diameter, and that free space is represented by a two-fluid model (the fluids oppositely charged). There are mappings which can transform such toroidal entities (photons) into spherical ones. The toroidal entities are possible candidates for the role of “hidden variables.”. (shrink)

I propose to consider photon tunneling as a space-time correlation phenomenon between the emission and absorption of a photon on the two sides of a barrier. Standard technics based on an appropriate counting rate formula may then be applied to derive the tunneling time distribution without any ad hoc definition of this quantity. General formulae are worked out for a potential model using Wigner–Weisskopf method. For a homogeneous square barrier in the limit of zero tunneling probability a vanishing (...) tunneling time is obtained. (shrink)