Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces

We observe the shift of Rydberg levels of rubidium close to a copper surface when atomic clouds are repeatedly deposited on it. We measure transition frequencies of rubidium to S and D Rydberg states with principal quantum numbers n between 31 and 48 using the technique of electromagnetically induced transparency. The spectroscopic measurement shows a strong increase of electric fields towards the surface that evolves with the deposition of atoms. Starting with a clean surface, we measure the evolution of electrostatic fields in the range between 30 and 300 \mum from the surface. We find that after the deposition of a few hundred atomic clouds, each containing ~10^6 atoms, the field of adsorbates reaches 1 V/cm for a distance of 30 \mum from the surface. This evolution of the electrostatic field sets serious limitations on cavity QED experiments proposed for Rydberg atoms on atom chips.Comment: 4 pages, 3 figures Submitted to Phys. Rev.

Measurement of absolute transition frequencies of 87Rb to nS and nD Rydberg states by means of electromagnetically induced transparency

We report the measurement of absolute excitation frequencies of 87Rb to nS and nD Rydberg states. The Rydberg transition frequencies are obtained by observing electromagnetically induced transparency on a rubidium vapor cell. The accuracy of the measurement of each state is < 1 MHz, which is achieved by frequency stabilizing the two diode lasers employed for the spectroscopy to a frequency comb and a frequency comb calibrated wavelength meter, respectively. Based on the spectroscopic data we determine the quantum defects of 87Rb, and compare it with previous measurements on 85Rb. We determine the ionization frequency from the 5S1/2(F=1) ground state of 87Rb to 1010.0291646(3) THz, providing the binding energy of the ground state with an accuracy improved by two orders of magnitude

State-selective all-optical detection of Rydberg atoms

We present an all-optical protocol for detecting population in a selected Rydberg state of alkali atoms. The detection scheme is based on the interaction of an ensemble of ultracold atoms with two laser pulses: one weak probe pulse which is resonant with the transition between the ground state and the first excited state, and a pulse with high intensity which couples the first excited state to the selected Rydberg state. We show that by monitoring the absorption signal of the probe laser over time, one can deduce the initial population of the Rydberg state. Furthermore, it is shown that – for suitable experimental conditions – the dynamical absorption curve contains information on the initial coherence between the ground state and the selected Rydberg state. We present the results of a proof-of-principle measurement performed on a cold gas of 87Rb atoms. The method is expected to find application in quantum computing protocols based on Rydberg atoms

Original Boy's Dormitory "The Cracker Box"

A photograph of the original men's dormitory prior to the completion of Foster Hall in 1926. The single level structure has a covered portico and semi-vaulted roof. A group of men pose at the front right corner of the structure. A small cluster of men are sitting on the roof while a larger group stands on the ground directly below. The foreground of the photo shows a grassy small knoll.This photograph is in fair condition. Two divots can be seen etched into the glossy finish of the photo. There are also various creases and handling indents. The handwritten remarks are on the back of the photo which reads, "Boy's dorm - 1918 (basement of Foster Hall) September." The first men's dormitory was built in 1918 with a $10,000 grant by the Woman's Board of Home Missions. The limited funds allowed only for a "makeshift" structure which consisted of a basement with a structure built around it. The dormitory was later converted into the basement of Foster Hall built in 1926. For more information and sources concerning "the cracker box" consult the following source: Brackenridge, R. Douglas. Westminster College of Salt Lake City. Logan, Utah: Utah State University Press, 1998, pp. 140