Electron interferometer
Encyclopedia
An Electron interferometer is an interferometer based on exploiting the wave character of electrons.
inherently depends on the wave nature of the object. As pointed out by de Broglie in his PhD-thesis, particles, including electrons can behave
like waves (the so called Wave-particle duality, now explained in the general framework of quantum mechanics). One of the first interferometry experiments with
electrons was the Double-slit experiment
. Since electrons are charged
, they repel each other, thus rendering the theoretical analysis more difficult than for
uncharged sources like, e.g., neutron
s or atom
s. To obtain high precision the de Broglie wave length needs to be small, which again favours neutrons or (heavy)
atoms since they have a higher mass
. Therefore many high precision experiments now deploy atom interferometer
s based on the Sagnac effect
.
Overview
InterferometryInterferometry
Interferometry refers to a family of techniques in which electromagnetic waves are superimposed in order to extract information about the waves. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy,...
inherently depends on the wave nature of the object. As pointed out by de Broglie in his PhD-thesis, particles, including electrons can behave
like waves (the so called Wave-particle duality, now explained in the general framework of quantum mechanics). One of the first interferometry experiments with
electrons was the Double-slit experiment
Double-slit experiment
The double-slit experiment, sometimes called Young's experiment, is a demonstration that matter and energy can display characteristics of both waves and particles...
. Since electrons are charged
Electric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
, they repel each other, thus rendering the theoretical analysis more difficult than for
uncharged sources like, e.g., neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s or 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...
s. To obtain high precision the de Broglie wave length needs to be small, which again favours neutrons or (heavy)
atoms since they have a higher mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
. Therefore many high precision experiments now deploy atom interferometer
Atom interferometer
An Atom interferometer is an interferometer based on exploiting the wave character of atoms. Interferometers are often used to make high-precision comparisons of distances. This can be used to constrain fundamental constants like the Gravitational Constant or possibly to detect Gravitational...
s based on the Sagnac effect
Sagnac effect
The Sagnac effect , named after French physicist Georges Sagnac, is a phenomenon encountered in interferometry that is elicited by rotation. The Sagnac effect manifests itself in a setup called ring interferometry. A beam of light is split and the two beams are made to follow a trajectory in...
.