Synopsis: Noisy conductors shed light

A time-tested photon interferometry technique is used to study the statistics of photons emitted by current fluctuations in a quantum conductor.
Synopsis figure
Illustration: Courtesy of E. Zakka-Bajjani, CEA, France

A quantum conductor with current fluctuations emits photons. When the conductor is at equilibrium, these photons exhibit chaotic statistics, similar to that seen in radiation off a black body. However, once the conductor is dislodged from equilibrium (for example, to a regime where the currents fluctuate due to quantum shot noise), the photon statistics is expected to become more complicated.

In trying to understand the connection between quantum conductors and quantum optics, theorists have made different predictions on the nature of this non-Poissonian statistics. Writing in Physical Review Letters, Eva Zakka-Bajjani and colleagues at CEA in Saclay, France, study the statistics of microwave photons in a low-temperature tunnel junction with shot noise. They investigate photon correlations using the so-called Hanbury Brown-Twiss interferometer setup, first used in 1956 to study interference patterns in starlight. A couple of theoretical papers [1] in the early 2000s explained that a mesoscopic conductor could emit photons with nonclassical, possibly sub-Poissonian, statistics. The authors at Saclay have tested that theory on the simplest quantum conductor: a tunnel junction. They find that, in agreement with that theory, photons emitted off the tunnel junction do exhibit chaotic statistics, even with low electron noise (fewer photons). Their work also provides a general guide to studying photon statistics of mesoscopic conductors with stronger electronic correlations. – Sami Mitra

[1] C. W. J. Beenakker and H. Schomerus, Phys. Rev. Lett. 86, 700 (2001); Phys. Rev. Lett. 93, 096801 (2004).


Announcements

More Announcements »

Subject Areas

OpticsMesoscopics

Previous Synopsis

Next Synopsis

Atomic and Molecular Physics

Entropy and order in optical lattices

Read More »

Related Articles

Synopsis: Tiny Oscillator Works as Photon Changing Room
Quantum Physics

Synopsis: Tiny Oscillator Works as Photon Changing Room

A new device converts the frequency of a photon using the vibrations in a mechanical oscillator. Read More »

Synopsis: All-Around Single-Photon Source
Quantum Information

Synopsis: All-Around Single-Photon Source

A quantum dot embedded in a micropillar is an efficient source of pure and indistinguishable single photons. Read More »

Viewpoint: Exorcising Maxwell’s Demon
Mesoscopics

Viewpoint: Exorcising Maxwell’s Demon

A pair of connected single-electron devices functions as a Maxwell’s demon that operates without external control. Read More »

More Articles