A solid state light-matter interface at the single photon level

Coherent and reversible mapping of quantum information between light and matter is an important experimental challenge in quantum information science. In particular, it is a decisive milestone for the implementation of quantum networks and quantum repeaters. So far, quantum interfaces between light and atoms have been demonstrated with atomic gases, and with single trapped atoms in cavities. Here we demonstrate the coherent and reversible mapping of a light field with less than one photon per pulse onto an ensemble of 10 millions atoms naturally trapped in a solid. This is achieved by coherently absorbing the light field in a suitably prepared solid state atomic medium. The state of the light is mapped onto collective atomic excitations on an optical transition and stored for a pre-programmed time up of to 1 mu s before being released in a well defined spatio-temporal mode as a result of a collective interference. The coherence of the process is verified by performing an interference experiment with two stored weak pulses with a variable phase relation. Visibilities of more than 95% are obtained, which demonstrates the high coherence of the mapping process at the single photon level. In addition, we show experimentally that our interface allows one to store and retrieve light fields in multiple temporal modes. Our results represent the first observation of collective enhancement at the single photon level in a solid and open the way to multimode solid state quantum memories as a promising alternative to atomic gases.Comment: 5 pages, 5 figures, version submitted on June 27 200

Interference of multi-mode photon echoes generated in spatially separated solid-state atomic ensembles

High-visibility interference of photon echoes generated in spatially separated solid-state atomic ensembles is demonstrated. The solid state ensembles were LiNbO$_3$ waveguides doped with Erbium ions absorbing at 1.53 $\mu$m. Bright coherent states of light in several temporal modes (up to 3) are stored and retrieved from the optical memories using two-pulse photon echoes. The stored and retrieved optical pulses, when combined at a beam splitter, show almost perfect interference, which demonstrates both phase preserving storage and indistinguishability of photon echoes from separate optical memories. By measuring interference fringes for different storage times, we also show explicitly that the visibility is not limited by atomic decoherence. These results are relevant for novel quantum repeaters architectures with photon echo based multimode quantum memories

Interference of Spontaneous Emission of Light from two Solid-State Atomic Ensembles

We report an interference experiment of spontaneous emission of light from two distant solid-state ensembles of atoms that are coherently excited by a short laser pulse. The ensembles are Erbium ions doped into two LiNbO3 crystals with channel waveguides, which are placed in the two arms of a Mach-Zehnder interferometer. The light that is spontaneously emitted after the excitation pulse shows first-order interference. By a strong collective enhancement of the emission, the atoms behave as ideal two-level quantum systems and no which-path information is left in the atomic ensembles after emission of a photon. This results in a high fringe visibility of 95%, which implies that the observed spontaneous emission is highly coherent

Spectroscopic investigations of a Ti:Tm:LiNbO3 waveguide for photon-echo quantum memory

We report the fabrication and characterization of a Ti$^{4+}$:Tm$^{3+}$:LiNbO$_3$ optical waveguide in view of photon-echo quantum memory applications. In particular, we investigated room- and cryogenic-temperature properties via absorption, spectral hole burning, photon echo, and Stark spectroscopy. We found radiative lifetimes of 82 $\mu$s and 2.4 ms for the $^3$H$_4$ and $^3$F$_4$ levels, respectively, and a 44% branching ratio from the $^3$H$_{4}$ to the $^3$F$_4$ level. We also measured an optical coherence time of 1.6 $\mu$s for the $^3$H$_6\leftrightarrow{}^3$H$_4$, 795 nm wavelength transition, and investigated the limitation of spectral diffusion to spectral hole burning. Upon application of magnetic fields of a few hundred Gauss, we observed persistent spectral holes with lifetimes up to seconds. Furthermore, we measured a linear Stark shift of 25 kHz$\cdot$cm/V. Our results are promising for integrated, electro-optical, waveguide quantum memory for photons.Comment: 11 pages, 14 figure

The Impact of Free Health Screenings at Community Pharmacies on Diabetes

Background: Health screenings can be beneficial when looking to detect diseases early on, thus making treatment easier. Free health screenings are typically performed in the community pharmacy setting. This makes it convenient because it is easily accessible and there is no appointment required. Diabetes is currently one of the most significant health issues faced today, with an estimated 7 million Americans going undiagnosed. Health screenings in community pharmacies are valuable to detect high blood glucose levels for patients to be referred for diagnosis and treatment. Previous studies related to health screenings have focused on hypertension and cholesterol, and few have been conducted on diabetes alone. Extensive research has not been performed regarding patient knowledge of diabetes or on the impact of health screenings. Due to this lack of research and the prevalence of diabetes, it is essential to explore the impact of free health screenings in regards to this growing health care issue. Objective: To assess the impact of free health screenings in community pharmacies on patient follow-up, perceptions, and knowledge of diabetes through blood glucose screenings and patient education. Methods: Data will be collected from local Kroger pharmacies. Patients will be purposefully selected based on inclusion and exclusion criteria. Selected patients will be given a pre-survey at baseline prior to blood glucose testing and diabetes education. Individuals with abnormally high blood glucose levels will be referred to see a physician. Referred participants will be called a month after referral regarding the follow-up with their physician and potential diabetes diagnosis. All of the subjects will be called after a month to remind them to complete the post-survey. The post-survey will be sent to individuals by mail or email a month after the pre-survey. These surveys will contain the exact same questions as the pre-survey

MeV neutrinos in double beta decay

The effect of Majorana neutrinos in the MeV mass range on the double beta decay of various isotopes is studied on pure phenomenological arguments. By using only experimental half life data, limits on the mixing parameter $U_{eh}^2$ of the order 10$^{-7}$ can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined.Comment: 7 pages, 6 uudecoded EPS-figure

The Impact of Free Health Screenings at Community Pharmacies on Diabetes

Diabetes is a prevalent issue in the United States, with an estimated 8.1 million people un-diagnosed as of 2012. Health screenings have been proven to identify diseases earlier, thereby resulting in earlier and more satisfactory treatment. Community pharmacies can offer many of the same screenings as those in doctor offices. The objective of this study was to assess the impact of free health screenings in community pharmacies on patient follow-up, perceptions, and knowledge of diabetes through blood glucose screenings and patient education. The study design was a pre-post observational study using surveys, blood sugar screenings, and patient education on diabetes. Participants were voluntary patients from four REM Corporation pharmacies in Ohio who were 18 or older, not recently tested for diabetes, non-diabetic, not pregnant, and without disorders that could hinder survey responses and education. Pre- and post-surveys assessed both patient perceptions on free health screenings in community pharmacies and on diabetes knowledge. Results among the 26 participants showed there was no statistically significant difference between patient perception pre- and post-surveys (all p-values ≥ 0.05), however there was a statistically significant difference between pre and post diabetes knowledge surveys (p \u3c 0.001). Limitations of this study were the small sample size due to the relatively small pharmacies utilized and short length of study time. Future directions should focus on using more demographically diverse pharmacies and a longer study time. Due to patients already having highly positive perceptions of health screenings in community pharmacies, future research should assess patient knowledge of diseases and the impact of patient education on overall health outcomes. Results of the study showed patients had positive opinions on free health screenings in community pharmacies and these screenings can help patients understand disease states and be more aware of their health

Photoassociation inside an optical dipole trap: absolute rate coefficients and Franck-Condon factors

We present quantitative measurements of the photoassociation of cesium molecules inside a far-detuned optical dipole trap. A model of the trap depletion dynamics is derived which allows to extract absolute photoassociation rate coefficients for the initial single-photon photoassociation step from measured trap-loss spectra. The sensitivity of this approach is demonstrated by measuring the Franck-Condon modulation of the weak photoassociation transitions into the low vibrational levels of the outer well of the 0g- state that correlates to the 6s+6p3/2 asymptote. The measurements are compared to theoretical predictions. In a magneto-optical trap these transitions have previously only been observed indirectly through ionization of ground state molecules