\large Relativity is the theory of particles moving with speeds comparable to the speed of light $v \sim c$ ($c$ is speed of light). Quantum mechanics is the theory describing the motion of microscopic particles. If we want to explain the behavior of microscopic particles moving with very high velocities (or high energies comparable to their rest mass energy) we need a theory which encapsulates both; the principles of relativity and quantum mechanics. So we need a quantum mechanical theory consistent with relativity. \par
\section{Why Quantum field Theory}
$\bullet$ Quantization of single relativistic particles leads to unphysical situations like negative energy states and negative probability density.
\\ $ \bullet $ Causality is not preserved in non-relativistic quantum mechanics, but as we know from the special relativity that for any theory
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This can be explained by saying that there is a proton field pervading throughout the whole universe and protons are quanta of this field.
\section{Elements of Classical Field Theory}
Classical Field theory deals with systems having infinitely large degrees of freedom. In case of infinite degrees of freedom the dynamical variables are no longer position and momentum of individual particles,the dynamical quantity is field, position and momentum become labels. For example we can think about a system having infinite number of springs coupled to each other then to describe the system, we use the vibration amplitude of those springs as a dynamical variable $\phi (x)$.\par
\subsection{Lagrangian Formalism}
In classical mechanics, we define action as time integral of Lagrangian. In field theory Lagrangian $L$ can be written as volume integral of Lagrangian density $\mathcal{L}$. Where $\mathcal{L}$ is a function of field ($\phi(x)$) and it's derivative ($\partial_{\mu}
The amazing transformation the study of physics underwent in the two decades following the turn of the 20th century is a well-known story. Physicists, on the verge of declaring the physical world “understood”, discovered that existing theories failed to describe the behavior of the atom. In a very short time, a more fundamental theory of the ...
...hes. In Alice and Quantumland, the principles or concepts of quantum mechanics are compared with the macro world; one can find great similarities and even greater dissimilarities between the world wherein electrons rule, and the world wherein human beings live. The author, Robert Gilmore, creates an allegory based off the principles of quantum mechanics using the original story of Alice in Wonderland. Through Alice’s adventure in Quantumland she comes across some ideas or features that contradict real world ideas. These ideas are the following: Electrons have no distinguishing spin, the Pauli Exclusion Principle, Superposition, Heisenberg Uncertainty Principle, and . All of these features are comprised essentially of the same universal concept--that the quantum world does not require definity whereas the macro world uses it as a pillar of society and civilization.
In the 1920s the new quantum and relativity theories were engaging the attentions of science. That mass was equivalent to energy and that matter could be both wavelike and corpuscular carried implications seen only dimly at that time. Oppenheimer's early research was devoted in particular to energy processes of subatomic particles, including electrons, positrons, and cosmic rays. Since quantum theory had been proposed only a few years before, the university post provided him an excellent opportunity to devote his entire career to the exploration and development of its full significance. In addition, he trained a whole generation of U.S. physicists, who were greatly affected by his qualities of leadership and intellectual independence.
“All manner of nonphysical phenomena may coexist with [physical phenomena], even to the extent of sharing the same space-time, provided only that the nonphysical phenomena are entirely inefficacious with respect to the physical phenomena.” (p. 24)
The Theory of Relativity, proposed by the Jewish physicist Albert Einstein (1879-1955) in the early part of the 20th century, is one of the most significant scientific advances of our time. Although the concept of relativity was not introduced by Einstein, his major contribution was the recognition that the speed of light in a vacuum is constant and an absolute physical boundary for motion. This does not have a major impact on a person's day-to-day life since we travel at speeds much slower than light speed. For objects travelling near light speed, however, the theory of relativity states that objects will move slower and shorten in length from the point of view of an observer on Earth. Einstein also
Quantum Mechanics This chapter compares the theory of general relativity and quantum mechanics. It shows that relativity mainly concerns that microscopic world, while quantum mechanics deals with the microscopic world.
Quantum Mechanics is a branch of physics that describes the structure and behavior of matter.
... a theory should be able to explain a wide variety of things, not just only what it was intended to explain.
Protons are positively charged and electrons are negatively charged. Protons and electrons both have charges of equal magnitude (i.e. 1.602x10-19 coulombs). Neutrons have a neutral charge, and they, along with protons, are the majority of the mass in an atom. Electron mass, though, is negligible. When an atom has a neutral charge, it is stable.
The theory of quantum mechanics has divided the atom into a number of fundamental sub-atomic particles. Although the physicist has shown that the atom is not a solid indivisible object, he has not been able to find a particle which does possess those qualities. Talk of particles, though, is misleading because the word suggests a material object. This is not the intention for the use of the word in quantum physics. Quantum particles are, instead, representations of the actions and reactions of forces at the sub-atomic level. In fact, physicists are less concerned with the search for a material particle underlying all physical objects and more interested in explaining how nature works. Quantum theory is the means that enables the physicist to express those explanations in a scientific way.
Quantum mechanics was pioneered by Max Planck, who developed the formula E = hv—which is the base for much of the quantum mechanical field. Quantum theory (the origin of quantum mechanics), as described in Talking Tech, was, at its early core, a handful of theories and hypotheses regarding energy quantization and wave-particle duality (Rheingold and Levine). The book goes on to explain how this realm of science is basically an extension of physics attempting to derive a mathematical specification of how the entirety of the universe operates and behaves at the subatomic level. Conversely, it also describes how quantum theory also diverges from classical physics in that it stipulates that the only...
Matter is energy (Fernflores 1). The fact that electron-positron interactions can either produce photons or...
In The Quantum Enigma, Rosenblum and Kuttner address the impact of the “Newtonian worldview” on our ability to understand and explain the phenomena of the physical world. Science has been able to greatly advance our knowledge of the natural world over the last several centuries largely due to this worldview. In this paper, five tenets of the Newtonian worldview will be summarized; two of these points—those found to be the most and least defensible—will be discussed in greater detail. As a final point, a discussion will be laid out regarding which of the five precepts, if rejected by modern physics, would be the most disturbing to give up.
Both of their theories have similarities but as life keeps going they start to differ from each others theories. Parts of their theories have helped find the correct information for what actually happens in human life development.
...pecial relativity has caused profound changes in the way we view our universe at its most fundamental level. The theory has had an effect on many areas of science, especially physics. Even though many people did not think that special relativity was anything more than a theoretical idea, it has been tested numerous times. In every case, the predictions of special relativity are upheld. Special relativity is a cornerstone upon which modern physics has been built, and it is one of the greatest discoveries of the twentieth century.