Physicists have long believed that nature has an underlying simplicity and that the number of fundamental forces can be reduced. Einstein spent most of his working life trying to interpret these forces as different aspects of a single superforce. He failed, but in the 1960s and 1970s, other physicists showed that the weak force and the electromagnetic force are different aspects of a single electroweak force. The quest for further reduction with the goal of unification continues today, at the very forefront of physics.
Called GUT, this is the most orthodox theory of unifying fundamental forces of nature. The current task at hand is to unify the strong, weak, and electromagnetic forces.
These theories seek to unify all forces, including the gravitational force, with a single framework.
These theories interpret pointlike particles, such as electrons, as being unimaginable tiny, closed loops. Interestingly enough, this theory proposes the idea that the universe may not consist of only four dimensions as Einstein saw it, but instead ten dimensions.
Whereas nuclear physics attempts to explain everything that occurs at the nuclear level, quantum mechanics gives us a physical interpretation of what occurs at the atomic level. We mention quantum mechanics because some see it as the "bridge" between classical and nuclear physics.
Quantum mechanics is the study of physics at the "quantum" level. The application of quantum mechanics to problems involving nuclei, atoms, molecules, and matter in the solid state made it possible to understand a vast body of otherwise-puzzling data. It has been shown that classical mechanics (regular physics) is but an approximation of quantum mechanics. The fundamnetal difference between the two lies in what they describe. In classical mechanics, the future history of a particle is completely determined by its initial position and momentum together with the forces that act upon it. In the the everyday world these quantities can all be determined well enough for the predictions of classical mechanics to agree with what we find.
Quantum mechanics also arrives at relationships between observable quantities, but the uncertainty principle (position and momentum can never be precisely determined) suggests that the nature of an observable quantity is different in the atomic realm. Cause and effect are still related in quantum mechanics, but what they concern needs careful interpretation. In quantum mechanics the kind of certainty about the future characteristic of classical mechanics is impossible because the initial state of a particle cannot be established with sufficient accuracy.
At first glance quantum mechanics seems a poor substitute for classical mechanics. However, closer inspection reveals taht classical mechanics is just an approximate version of quantum mechanics. The certainties proclaimed by classical mechanics are illusory, and their agreement with experiment occurs only because ordinary objects consist of so many individual atoms taht departures from average behavior are unnoticeable. Instead of two sets of physical principles, one for the macroworld and one for the microworld, there is only a single set, and quantum mechanics represents our best effort to date in formulating it.
Particle physics is one of the largest physical fields of current study. Although our web site sings the tune of nuclear physics, particle physics might well be the physics of the future as according to it, nuclear physics can be seen from a different viewpoint, maybe an intrinsically simpler viewpoint. Particle physics considers every single type of interaction to take place between particles with particles as carriers.
Ordinary matter is composed of protons, neutrons, and electrons, and at first glance, these particles seem enough to account for thd structure of the universe around us. Not all nuclides are stable, however, and particles called neutrinos are needed for beta decay to take place. Furthermore, the electromagnetic interaction between charged particles requires photons as its carrier, and the specifically nuclear interaction between nucleons requires particles known as pions for the same purpose.
But things are not nearly so straightforward. Several hundred other elementary particles have been discovered in recent years. Different particles interact in different ways with matter. These interactions are important from a practical point of view because they underlie the use of various kinds of radiaiton ion research, in industry, and in medicine.