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A “Schrödinger’s cat”-type effect entangles collective excitations in a semiconductor nanostructure, making a new infrared light source.

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  A “Schrödinger’s cat”-type effect entangles collective excitations in a semiconductor nanostructure, making a new infrared light source. Sam Wormley <swormley1@gmail.com> - 2015-10-29 16:08 -0500
    Re: A Schrödingers cat-type effect entangles collective excitations in a semiconductor nanostructure, making a new infrared light source. jimp@specsol.spam.sux.com - 2015-10-29 21:39 +0000

#528958 — A “Schrödinger’s cat”-type effect entangles collective excitations in a semiconductor nanostructure, making a new infrared light source.

A “Schrödinger’s cat”-type effect entangles collective excitations in a 
semiconductor nanostructure, making a new infrared light source.
> http://physics.aps.org/articles/v8/104


> The concert is about to start: Brahms’ First. The hall is cacophonous
> with tuning instruments. The oboe shrieks, the horn blurts out. An
> instant later, with the downbeat of the baton, perfect harmony
> sounds. The physics is simple. The conductor brings the
> instruments—harmonic oscillators—together, locking them in phase.
> Coherence sets in. Such classical analogies often serve to introduce
> coherent quantum phenomena, but miss a crucial point: quantum
> particles are fundamentally indistinguishable. In this orchestral
> analogy, we cannot ascertain which violin is playing and which one is
> not. The physicist Robert Dicke worked through this problem some 60
> years back [1]. He found that the quantum phases of oscillators can
> be related even if only one is excited; two violins sound as if they
> are both playing when only one is bowed. While beautiful in
> conceptual simplicity, manifestations of such phase coherence (the
> “Dicke effect”) are challenging to find [2]. Now, Carlo Sirtori from
> the University of Paris Diderot, France, and colleagues provide
> evidence for the Dicke effect in infrared (IR) light emission from a
> semiconductor nanostructure at room temperature [3]. The device
> constitutes a kind of IR light-emitting diode (LED) with potential
> applications in biochemical sensing.
>
> Dicke’s theory, one of Physical Review’s collection of papers for
> UNESCO’s International Year of Light, describes how phase-coherent
> collective emission emerges in a gas of noninteracting identical
> atoms. The energy of a photon from a light field shone on the gas can
> only be absorbed by one of the atoms, which transitions from its
> ground to its excited state. Because of quantum indistinguishability,
> it remains undefined which one. The collection of atoms that see the
> light field is therefore described as being in a quantum entanglement
> of ground and excited states—much like Schrödinger’s cat is
> simultaneously dead and alive, entangled between both states. The
> more atoms present, the more entangled the system becomes. From this
> entanglement, new atomic transitions emerge with different transition
> rates. Under specific conditions, each of the individual transitions
> is shared between the different atoms, so that the interaction rate
> of the ensemble with the light field increases and the atoms
> collectively emit light: superradiance occurs, the “atomic
> quantum-orchestra plays.”


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#528968 — Re: A Schrödingers cat-type effect entangles collective excitations in a semiconductor nanostructure, making a new infrared light source.

Sam Wormley <swormley1@gmail.com> wrote:

USENET is ascii; you are cut and pasting HTML encoded characters.


-- 
Jim Pennino

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