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In quantum optics, superradiance is a phenomenon that occurs when a group of N emitters, such as excited atoms, interact with a common light field. If the wavelength of the light is much greater than the separation of the emitters, [2] then the emitters interact with the light in a collective and coherent fashion. [3]
Dicke superradiance is a collective phenomenon in which many two-level systems emit photons coherently in free space. [ 2 ] [ 18 ] It occurs if the two-level systems are initially prepared in their excited state and placed at a distance much smaller than the relevant photon's wavelength.
Despite the original model of the superradiance the quantum electromagnetic field is totally neglected here. The oscillators may be assumed to be placed for example on the cubic lattice with the lattice constant in the analogy to the crystal system of the condensed matter. The worse scenario of the defect of the absence of the two out-of-the ...
Another definition of the Bessel function, for integer values of n, is possible using an integral representation: [7] = () = (()), which is also called Hansen-Bessel formula. [ 8 ] This was the approach that Bessel used, [ 9 ] and from this definition he derived several properties of the function.
A superradiant laser is a laser that does not rely on a large population of photons within the laser cavity to maintain coherence. [1] [2]Rather than relying on photons to store phase coherence, it relies on collective effects in an atomic medium to store coherence.
Frequency-resolved optical gating (FROG) is a general method for measuring the spectral phase of ultrashort laser pulses, which range from subfemtosecond to about a nanosecond in length.
The Rashba effect, also called Bychkov–Rashba effect, is a momentum-dependent splitting of spin bands in bulk crystals [note 1] and low-dimensional condensed matter systems (such as heterostructures and surface states) similar to the splitting of particles and anti-particles in the Dirac Hamiltonian.
The magnitude of an object's solid angle in steradians is equal to the area of the segment of a unit sphere, centered at the apex, that the object covers.Giving the area of a segment of a unit sphere in steradians is analogous to giving the length of an arc of a unit circle in radians.