Atomic electron transition is a change (or jump) of an

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

from one

energy level A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The t ...

to another within an

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, ...

artificial atom Quantum dots (QDs) are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology. When the q ...

. It appears discontinuous as the electron "jumps" from one quantized energy level to another, typically in a few

nanosecond A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or 10 seconds. The term combines the SI prefix ''nano-'' indicating a 1 billionth submultiple of an SI unit ( ...

s or less. It is also known as an electronic (de-)excitation or atomic transition or quantum jump. Electron transitions cause the emission or absorption of

electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) li ...

in the form of quantized units called

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they a ...

s. Their statistics are Poissonian, and the time between jumps is

exponentially distributed In probability theory and statistics, the exponential distribution is the probability distribution of the time between events in a Poisson point process, i.e., a process in which events occur continuously and independently at a constant averag ...

. The damping time constant (which ranges from

s to a few seconds) relates to the natural, pressure, and field broadening of spectral lines. The larger the energy separation of the states between which the electron jumps, the shorter the

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, t ...

of the photon emitted.

History

Danish physicist

Niels Bohr Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...

first theorized that electrons can perform quantum jumps in 1913. Soon after,

James Franck James Franck (; 26 August 1882 – 21 May 1964) was a German physicist who won the 1925 Nobel Prize for Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed his doctorate i ...

and

Gustav Ludwig Hertz Gustav Ludwig Hertz (; 22 July 1887 – 30 October 1975) was a German experimental physicist and Nobel Prize winner for his work on inelastic electron collisions in gases, and a nephew of Heinrich Rudolf Hertz. Biography Hertz was born in Hamb ...

proved experimentally that atoms have quantized energy states. The observability of quantum jumps was predicted by

Hans Dehmelt Hans Georg Dehmelt (; 9 September 1922 – 7 March 2017) was a German and American physicist, who was awarded a Nobel Prize in Physics in 1989, for co-developing the ion trap technique ( Penning trap) with Wolfgang Paul, for which they shared one ...

in 1975, and they were first observed using trapped ions of mercury at NIST in 1986.

Recent discoveries

In 2019, it was demonstrated in an experiment with a superconducting

consisting of two strongly-hybridized transmon qubits placed inside a readout resonator cavity at 15 m K, that the evolution of some jumps is continuous, coherent, deterministic, and reversible. On the other hand, other quantum jumps are inherently unpredictable.

References

External links

*
Part 2

"There are no quantum jumps, nor are there particles!"
by H. D. Zeh, ''Physics Letters'' A172, 189 (1993). *
"Surface plasmon at a metal-dielectric interface with an epsilon-near-zero transition layer"
by Kevin Roccapriore et al., ''Physical Review B'' 103, L161404 (2021). {{DEFAULTSORT:Atomic Electron Transition Atomic physics Electron states

History

Recent discoveries

See also

References

External links