Today scientists believe that all “particles” also have a “wave nature” (and vice versa). This phenomenon has been verified not only for elementary particles, but also for the elementary particles that exist in compound particles like molecules and even atoms. You can consider light (the photons of the light beams) as a “wave-like energy”. This energy is a wave–particle, just containing elementary matter and speed. We can use Einstein, Planck equations to determine the amount of the energy which make up a sample photon. But, to date we cannot measure the matter, therefore we make a simple unit that let us to measure the matter.
Today scientists believe that all “particles” also have a “wave nature” (and vice versa). This phenomenon has been verified not only for elementary particles, but also for the elementary particles that exist in compound particles like molecules and even atoms. You can consider light (the photons of the light beams) as a “wave-like energy”. This energy is a wave–particle, just containing elementary matter and speed. We can use Einstein, Planck equations to determine the amount of the energy which make up a sample photon. But, to date we cannot measure the matter, therefore we make a simple unit that let us to measure the matter.
Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles also have a wave nature (and vice versa).[1] This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. For macroscopic particles, because of their extremely short wavelengths, wave properties usually cannot be detected.[2] Wave–particle duality is an ongoing conundrum in modern physics. Most physicists accept wave-particle duality as the best explanation for a broad range of observed phenomena; however, it is not without controversy.
Introduction It is believed that the basic physical building blocks forming the world we live in may be categorized into particles of matter and carriers of force between matter. All known elementary constituents of matter and transmitters of force are quantized. For example, energy, momentum, and angular momentum take on discrete quantized values. The electron is an example of an elementary particle of matter, and the photon is an example of a transmitter of force. Neutrons, protons, and atoms are composite particles made up of elementary particles of matter and transmitters of force. These composite particles are also quantized. Because classical mechanics is unable to explain quantization, we must learn quantum mechanics in order to understand the microscopic properties of atoms – which, for example, make up solids such as crystalline semiconductors. Historically, the laws of quantum mechanics have been established by experiment. The most important early experiments involved light. Long before it was realized that light waves are quantized into particles called photons, key experiments on the wave properties of light were performed. For example, it was established that the color of visible light is associated with different wavelengths of light. Table 2.1 shows the range of wavelengths corresponding to different colors. The connection between optical and electrical phenomena was established by Maxwell in 1864. This extended the concept of light to include the complete electromagnetic spectrum. A great deal of effort was, and continues to be, spent gathering information on the behavior of light.
Have you ever tried to define light? If so, your definition is probably related to vision, the ability to see things. The Merriam-Webster English dictionary defines light as “something that makes vision possible”. However, the definition of the “nature of light” is a complex term already discussed by philosophers of Ancient Greece. In the 17th century, the debate on the matter focused on whether light was a particle or a wave, based on the different properties of light that had been gradually discovered over time. Isaac Newton (1642−1727) was a defender of the corpuscular theory of light, which considered light to be formed by particles, i.e., small pieces of matter, like dust or grains of sand. He was the author of Opticks (1706), the front cover of which appears in Fig. 1.1. Christian Huygens (1629–1695), on the other hand, supported the theory that light is a wave. These are two completely different definitions of the same physical concept. A range of experiments were developed to attempt to clarify this dilemma, but it was only until 1900 when Max Planck (1858-1947) introduced the basis of a theory that would go on to revolutionize scientific thinking, marking the beginning of modern physics: quantum theory. Developed during the 20th century thanks to advances made by scientists such as Niels Bohr, Born, Heisenberg, Schrödinger, Pauli, Dirac, Einstein or de Broglie, quantum theory clarified that light is neither a particle nor a wave, but that it has a dual nature: it behaves like a wave as it spreads but like a particle in its interactions with matter. In this book, we will specify where necessary whether light behaves as a particle or as a wave, although in most cases we refer to rays of light, which always represent the direction of propagation of light.
The theory is based on a new hypothesis on the nature of matter. This hypothesis is that the elementary particles, atoms, and molecules we have found in nature are not part of the real world, but constitute information about the real world. They are the wave components of a generalized Fourier analysis of our observations (which in the final analysis are always space-time distributions of photon- or particle-counter clicks). This Fourier analysis should be so general that every observation can be expressed in its terms; it thereby becomes axiomatic. Physicists of past generations, with their sound instincts, were intuitively approaching this most general and most powerful possible analysis of our observations. With the discovery of quantum mechanics, this development had advanced so far that the precise formulation of this ultimate analysis could be guessed. The model which can guide us to this mathematical formulation is that of an ideal optical observation on a physical object. This observation is made by illuminating the object with a finite number of laser beams of known amplitude and phase, and observing the amplitude and phase of the finite number of light beams emerging from the object space. The assumption that this is all the information we can ever obtain about the object leads to a wave function of the object which consists of light waves, extrapolated from the photon detectors back to the object space. It is suggested that these light waves should be presented as a product of amplitudes in a 4n-dimensional space, where n is the number of light quanta in the signal. Most important, force, or interaction, can then be described as a linear transformation in this space. The actual mathematical formalism proposed on the basis of that model is Xf=dtitdf. X is the Hamiltonian of the whole universe with ${n}_{0}\ensuremath{\cong}{10}^{80}$ particles. It is a $4{n}_{0}\ifmmode\times\else\texttimes\fi{}4{n}_{0}$ linear matrix operator. f is a 4n0-component vector wave function representing waves traveling at the speed of light. The coordinates are the homogeneous coordinates (xj,yj,zj,uj) of the n0 particles in the closed universe. The eigenvalue $\ensuremath{\omega}$, in $Xf=\ensuremath{\omega}f$, is a $4{n}_{0}\ifmmode\times\else\texttimes\fi{}4{n}_{0}$ Hermitian matrix. It can be divided into ${n}_{0}\ifmmode\times\else\texttimes\fi{}{n}_{0}$, 4 \ifmmode\times\else\texttimes\fi{} 4 submatrices, each representing a complete set of dynamic and inertial quantities of elementary particles, or interaction quanta between particles. $\frac{\mathrm{it}df}{\mathrm{dt}}=\ensuremath{\omega}f$ is therefore a complete expression of the dynamic conservation laws. A special orthogonal transformation ${\ensuremath{\alpha}}_{0}$ transforms the solution into a standard solution with eigenvalue ${\ensuremath{\omega}}_{0}$, representing n0 identical elementary particles. The assumption that the universe is of maximum probability then leads to simple explicit expressions for all matrix elements of ${\ensuremath{\omega}}_{0}$. This means that the energy levels of all n-particle systems (atoms or molecules) of the theory can be directly calculated. The equations demand relations between cosmological constants and atomic constants. In a universe of the size and mass of our observed universe, the elementary particle would have to be the size of the proton.
In quantum mechanics, light cannot be described in terms of waves and particles at the same time. However, the question about light "as it really is" implies a description that is independent from the constraints of measurement. It is rather preferable to incorporate both aspects in a causal ontological theory, especially if it simplifies explanation and improves predictions. Hence, the photon can be described as an extended longitudinal association of discrete indivisible constituents, which are held together by the effect of their own waves on each other. The same waves can then be used to interpret the force of interactions between different pulses of light, or between light and matter. The concept of wavemediated interaction between sub-photonic entities is entirely consistent with the observations of quantum mechanics. The key is to assume that elementary sources of waves never collide, and that they have constant parameters. Novel experimental implications follow from this approach. For example, the speed of propagation of changes within magnetic or electrostatic fields may not be equal to the speed of light. Also, interference fringes should be detectable beyond the volume of overlap of two non-entangled beams, but only in special experimental settings.
At the turn of the 20th century, Max Planck and Albert Einstein introduced the quantum theory which revolutionized our understanding of the nature of energy, in particular the nature of light energy. According to Planck, energy is absorbed or emitted from hot objects in tiny discrete bundles called quanta, and each quantum carries a precise quantity of energy which is related to the frequency of light wave. Einstein generalized Planck’s quantum theory. Einstein’s quantum theory removed a grating asymmetry in nature, between energy and matter. Louis DeBroglie said proposed that if light waves behave as particles, electrons, normally thought of as particles, ought to reciprocally behave as waves. DeBroglie provided a crucial missing piece in the quantum puzzle of discrete Bohr orbitals. Erwin Schroedinger seized DeBroglie’s brain wave. He developed a “wave mechanics” to describe the quantum world. For Schroedinger, particles are just an “illusion” of many waves; he turned waves into particles.