What is causing trapped ions to heat up? In an ion trap, electrodes (shown here in gold) produce electric fields that confine the ion (green sphere) to a small volume. Randomly fluctuating dipoles on the surface of these electrodes generate electric field noise. The dipoles form when single atoms adsorb on the metal surface. Vibrations (phonons) in the metal cause the dipoles (purple arrows) to fluctuate. Ions trapped in the vicinity of the metal surface sense these electric field changes and heat up.

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Atomic and Molecular Physics

Physics 4, 66 (2011)DOI: 10.1103/Physics.4.66

All that is gold does not glitter

Nikos Daniilidis and Hartmut HäffnerDepartment of Physics, University of California, Berkeley, CA 94720-7300, USA

Published August 22, 2011

A microscopic model offers new insight into a pernicious source of electric field noise in ion traps.

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Microscopic model of electric-field-noise heating in ion traps

A. Safavi-Naini, P. Rabl, P. F. Weck, and H. R. Sadeghpour

Phys. Rev. A 84, 023412 (2011) – Published August 22, 2011

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Artificial Atoms Can Do More Than Atoms

In a recently published work in Physical Review Letters, we have shown that artificial atoms made of a large number of single atoms can exhibit superior properties compared to their individual counterparts. Our results provide a way to novel applications in photonic devices used for quantum communication and quantum metrology.

In our work, we investigate an ensemble of strongly interacting atoms as found in Rydberg atoms or semiconductor quantum dots. The interaction of these systems with light can be described by an artificial atom with only two energy levels. However, when applying controlled noise to the system, this approximation breaks down and additional energy levels have to be taken into account. If a light beam is then sent through the system, these additional levels result in exactly one photon being removed from the beam. This single photon absorption process can be used in number resolving photon counters or for the creation of non-classical states of light.

Reference: J. Honer, R. Löw, H. Weimer, T. Pfau, H. P. Büchler, Phys. Rev. Lett. 107, 093601 (2011).
See also: Synopsis in Physics