Uncertainty Principle of Werner Heisenberg | eBook | AudioBook

The Following is an Excerpt from this Book

The Uncertainty Principle, also known as the Heisenberg Uncertainty Principle or the Indeterminacy Principle, was formulated in 1927 by the German physicist Werner Heisenberg. It states that the position and momentum of an object cannot be determined exactly at the same time, except in a theoretical domain. In reality, the very definitions of the exact location and exact velocity together have no significance in nature. Ordinary knowledge does not lead to guidance to this theory. It is easy to measure both the position and the momentum of, say, the vehicle, since the uncertainties inherent in this theory for ordinary objects are too minimal to detect.

The precise rule stipulates that the product of uncertainty in location and velocity is equal to or greater than a small physical quantity or constant. It is only in the case of extremely small masses of atoms and subatomic particles that the result of uncertainty is important. Any attempt to calculate precisely the velocity of a subatomic particle, such as an electron, would have an unforeseen effect on it, such that the simultaneous calculation of its location is invalid. This finding has little to do with the inadequacy of the measurement devices, the methodology, or the observer; it results from the intimate relation in nature between the particles and the waves in the subatomic dimensional domain. Each particle has a wave associated with it; a particle actually exhibits wavelike action. The particle is most likely to be found in those areas where the waves are strongest or most powerful. Furthermore, the more violent the undulations of the related wave are, the more mal-defined the wavelength becomes, which in turn defines the momentum of the particle.

Therefore, a purely localized wave has an indeterminate wavelength; its corresponding particle, though having a certain location, does not have a certain velocity. Contrary to this, a particle-wave with a well-defined wavelength is spread out; the corresponding particle, though having a relatively definite velocity, maybe almost everywhere. A reasonably precise measurement of one variable entails a relatively significant uncertainty in the calculation of the other. Optionally, the idea of uncertainty is expressed in terms of the momentum and location of the particle. The velocity of a particle is equal to the product’s mass times its velocity. Thus, the sum of uncertainty in the momentum and position of the particle is equal to or greater than h/(4Δ), i.e. constant. The principle applies to other similar (conjugate) pairs of observables, such as time and energy: the product of uncertainty in the energy calculation and uncertainty in the time period during which the measurement is rendered is either equal to or greater than h/(4Δ). In the case of an unstable atom or nucleus, the same relationship occurs between the uncertainty in the amount of energy emitted and the uncertainty in the existence of the unstable system as it makes the transition to a more stable state.

The Heisenberg Theory of Uncertainty is sometimes called the Uncertainty principle. Werner Heisenberg hit upon the mystery of the universe: nothing has a definite location, a definite trajectory, or a definite momentum. Trying to pin a thing down to a certain location will make its momentum less well pinned down, and vice versa. In daily life, individuals can accurately calculate the location of a vehicle at a certain time and then determine its trajectory and speed (assuming that it is going along at a steady rate) over the next few moments. That’s because of the location and velocity uncertainties are so low that one cannot fathom them. One can presume quite rightly that the trajectory of the vehicle will not be significantly altered when a marker is dropped on the ground, and at the same time, a stopwatch is pressed to remember the location of the automobile in time and space. People may apply that knowledge to the world of atomic-sized phenomena, and mistakenly conclude that if they calculate the position of something like an electron as it travels along its course, it will continue to move along the same course that one considers can be precisely detected in the next few moments.

One needs to learn that the electron does not have a particular location before one searches it, nor does it have a definite momentum before the trajectory is measured. Besides, people can justifiably conclude that a photon emitted by a laser built for the detection screen will reach very close to its target on that screen and validate this prediction by any series of experiments. First, it will be discovered that the more people seek to pin down any place for the electron on its way to the detection screen, the more likely it and similar to this will miss the target. Therefore, pinning an electron position makes the trajectory more unpredictable, indeterminate, or unpredictable. If the trajectory is made simpler, and then one has to try to locate the electron along the length of the trajectory that he has just set out. Eventually, one would find that the more precise is the trajectory, the less likely one can find the electron where ordinary assumptions would lead one to believe it in.

Unexpected implications of the uncertainty character of nature help people’s understanding of issues such as nuclear fission, which has given mankind a fresh and powerful source of energy, and quantum tunneling, which is the operating principle of semiconductors that are so relevant to modern computers and other technologies. In technical debates, there is almost always speaking of position and momentum. Momentum is the sum of momentum and mass, and the concept of momentum in physics is the speed that it is moving in a certain direction. So sometimes people can just think about the velocity of the object in question and forget its mass, and many times it’s easier to understand if they are thinking about the direction or the path that anything follows. The theory also involves concepts of speed and direction. Heisenberg began working on quantum physics by modifying the classical equations for electricity, which were very challenging to begin with, and the mathematics behind his 1925 paper was very difficult to follow.