Quantum leap
Encyclopedia
In physics
and chemistry
, an atomic electron(ic) transition (could be simply called an atomic transition, a quantum jump, or quantum leap) is a change of an electron
from one quantum state to another within an atom
(or artificial atom). It appears to be discontinuous (observed for example in fluorescence
signal of another transition as burst noise
); the electron "jumps" from one energy level
to another very quickly (transition time
often in a few ns
or less). Quantum leaps cause the emission (or absorption) of electromagnetic radiation
, including that of light, which occurs in the form of quantized units called photon
s. Their statistics is Poissonian
and the damping of statistic values of time between jumps is exponential (in average). The damping time constant (ranges from nanoseconds
to a few seconds
) relates to the natural, pressure and field broadening of spectral lines.
Although changes of quantum state occur on the submicroscopic level, in popular discourse, the term "quantum leap" refers to a large increase (Oxford English Dictionary).
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, an atomic electron(ic) transition (could be simply called an atomic transition, a quantum jump, or quantum leap) is a change of an electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
from one quantum state to another within an atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
(or artificial atom). It appears to be discontinuous (observed for example in fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
signal of another transition as burst noise
Burst noise
Burst noise is a type of electronic noise that occurs in semiconductors. It is also called popcorn noise, impulse noise, bi-stable noise, or random telegraph signal noise....
); the electron "jumps" from one energy level
Energy level
A quantum mechanical system or particle that is bound -- that is, confined spatially—can only take on certain discrete values of energy. This contrasts with classical particles, which can have any energy. These discrete values are called energy levels...
to another very quickly (transition time
Transition time
The transition time \scriptstyle t_t\, is the time a dynamical system needs to switch between two different stable states, when responding to a stable input signal. In a logic circuit undergoing a change of state, it identifies the rise time or the fall time of the output voltage...
often in a few ns
Nanosecond
A nanosecond is one billionth of a second . One nanosecond is to one second as one second is to 31.7 years.The word nanosecond is formed by the prefix nano and the unit second. Its symbol is ns....
or less). Quantum leaps cause the emission (or absorption) of electromagnetic radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
, including that of light, which occurs in the form of quantized units called photon
Photon
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
s. Their statistics is Poissonian
Poisson distribution
In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since...
and the damping of statistic values of time between jumps is exponential (in average). The damping time constant (ranges from nanoseconds
Nanosecond
A nanosecond is one billionth of a second . One nanosecond is to one second as one second is to 31.7 years.The word nanosecond is formed by the prefix nano and the unit second. Its symbol is ns....
to a few seconds
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
) relates to the natural, pressure and field broadening of spectral lines.
Although changes of quantum state occur on the submicroscopic level, in popular discourse, the term "quantum leap" refers to a large increase (Oxford English Dictionary).
See also
- Burst noiseBurst noiseBurst noise is a type of electronic noise that occurs in semiconductors. It is also called popcorn noise, impulse noise, bi-stable noise, or random telegraph signal noise....
- FluorescenceFluorescenceFluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
- PhosphorescencePhosphorescencePhosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. The slower time scales of the re-emission are associated with "forbidden" energy state transitions in quantum...
- Stimulated emissionStimulated emissionIn optics, stimulated emission is the process by which an atomic electron interacting with an electromagnetic wave of a certain frequency may drop to a lower energy level, transferring its energy to that field. A photon created in this manner has the same phase, frequency, polarization, and...
- Molecular electronic transitionMolecular electronic transitionMolecular electronic transitions take place when electrons in a molecule are excited from one energy level to a higher energy level. The energy change associated with this transition provides information on the structure of a molecule and determines many molecular properties such as color...
for molecules
External links
- Are there quantum jumps?
- "There are no quantum jumps, nor are there particles!" by H. D. Zeh, Physics Letters A172, 189 (1993).