Measurements of the short-term stability of quartz crystal resonators: A window on future developments in crystal oscillators

Recent measurements of the inherent short-term stability of quartz crystal resonators are presented. These measurements show that quartz resonators are much more stable for times less than 1s than the best available commercial quartz oscillators. A simple model appears to explain the noise mechanism in crystal controlled oscillators and points the way to design changes which should permit more than 2 orders of magnitude improvement in their short-term stability. Calculations show that a reference signal at 1 THz, derived from frequency multiplying a 5 MHz source with the above measured crystal stability, should have an instantaneous or fast linewidth of order 1 Hz. These calculations explicitly include the noise contribution of our present multiplier chains and are briefly outlined

Absolute frequency measurements of the D2D_2 line and fine-structure interval in 39^{39}K

We report a value for the $D_2$-line frequency of $^{39}$K with 0.25 ppb uncertainty. The frequency is measured using an evacuated ring-cavity resonator whose length is calibrated against a reference laser. The $D_2$ line presents a problem in identifying the line center because the closely-spaced energy levels of the excited state are not resolved. We use computer modelling of the measured spectrum to extract the line center and obtain a value of 391 015 578.040(75) MHz. In conjunction with our previous measurement of the $D_1$ line, we determine the fine-structure interval in the $4P$ state to be 1 729 997.132(90) MHz. The results represent significant improvement over previous values.Comment: 4 pages, 3 figure

Transforming squeezed light into a large amplitude coherent state superposition

A quantum superposition of two coherent states of light with small amplitude can be obtained by subtracting a photon from a squeezed vacuum state. In experiments this preparation can be made conditioned on the detection of a photon in the field from a squeezed light source. We propose and analyze an extended measurement strategy which allows generation of high fidelity coherent state superpositions with larger amplitude.Comment: 6 pages, 4 figures, v2: published versio

Slosh test analysis for the 200-inch multicell tank

Slosh test analysis of multicell fuel tank

The Free Methodist Church: A Bibliography

https://place.asburyseminary.edu/freemethodistbooks/1006/thumbnail.jp

On Professional Discourse in Folklore: A Response to Oring

Open Foru

Does Your Education Have a Price?

Would you sell your home economics education for what it cost you? The question was put first to a college graduate who has been teaching home economics several years

Activities of the Merrill Palmer School

A new venture in education is the Merrill Palmer School, and we of Iowa State are most proud to have a part in it. Not only are we sending some of our senior women there, but our own vice-dean, Miss Edna Walls, is there tor this year. The accompanying article sent by Miss Walls is a clear explanation and a pleasant glimpse of school activitie

New and Noteworthy

Book Review