Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 34: Ultracold Atoms: Trapping and Cooling II (with Q)

A 34.5: Talk

Thursday, March 26, 2015, 15:30–15:45, P/H2

Measuring heating rate of ions in a planar ion trap with variable ion-surface separation — •Ivan Boldin, Alexander Kraft, and Christof Wunderlich — University of Siegen, 57068 Siegen, Germany

Planar electrode ion traps are considered to have great potential for quantum information science as: a) they are relatively easy to scale up and allow for complex electrode structures that might be needed for future quantum processors; b) ions can be trapped tens of micrometers above the surface, therefore strong static and oscillating field gradients can be imposed on ions and utilized in the realization of microwave qubit processing.

While reducing the ion-surface separation is advantageous for stronger field gradients and hence faster quantum gates, it also increases undesired interactions with the electrode surface. This heating is one of the major sources of decoherence and its mechanism is not well understood so far. In order to better understand this mechanism it is of interest to know how it depends on the ion-surface separation. Here we present the results of such heating rate measurements.

We have built a planar electrode ion trap in which the ion-surface distance can be varied in the range of 45 - 155 um by applying additional RF voltage to the central electrode. We measure the heating rates by recooling method i.e. allowing ion to heat up for a certain time and suddenly switching on the laser cooling and measuring the photon scattering rate over time. Fitting this curve with the theoretical allows estimation of the heating rate.