Atomic spin decoherence near conducting and superconducting films

Published versio

Shaking-induced dynamics of cold atoms in magnetic traps

We describe an experiment in which cold rubidium atoms, confined in an elongated magnetic trap, are excited by transverse oscillation of the trap center. The temperature after excitation exhibits resonance as a function of the driving frequency. We measure these resonances at several different trap frequencies. In order to interpret the experiments, we develop a simple model that incorporates both collisions between atoms and the anharmonicity of the real three-dimensional trapping potential. As well as providing a precise connection between the transverse harmonic oscillation frequency and the temperature resonance frequency, this model gives insight into the heating and loss mechanisms and into the dynamics of driven clouds of cold trapped atoms

Prognostic Information for Known Genetic Carriers of RB1 Pathogenic Variants (Germline and Mosaic)

OBJECTIVE: To compare the number of tumors per eye for mosaic carriers of RB1 pathogenic variants with full germline variants and the conversion from unilateral to bilateral disease. DESIGN: Retrospective cohort study comparing patients with retinoblastoma and different genetic subtypes (HP: high penetrant, LP: low penetrant & mosaicism). SUBJECTS: Data were analysed between 1992 and 2018 at the Retinoblastoma Unit, Royal London Hospital, London UK. All familial patients had a parent with a known pathogenic variant even if the parent did not manifest the disease. MAIN OUTCOME MEASURES: Number of tumors per eye in children who developed retinoblastoma in that eye. Other outcomes included total number of tumors per patient, age at diagnosis, laterality at presentation and later, sex and stage according to International Intraocular Retinoblastoma Classification RESULTS: 111 patients were included: 64 full germline, familial patients (53 HP and 11 LP) & 47 were mosaic patients. 12 (23%) of HP patients were unilateral and 8 of 12 (67%) developed tumors in their previously unaffected eye. 34 (72%) of mosaic patients were unilateral and only 2 (6%) developed tumors in their unaffected eye. Age at diagnosis was higher in mosaic patients (median 22 months) than HP patients (median 7) (p<0.00002). Number of tumors per eye was fewer in patients with mosaic alleles (median 1.0 range 1-6) compared to patients with HP alleles (median 3.0 range 1-8) (p<0.0003). All three children (4 eyes) with mosaicism and more than 2 tumors per eye had high levels of mosaicism. CONCLUSIONS: Children with mosaic alleles have fewer tumors per eye compared to those with known high penetrant pathogenic variants and are more likely to remain unilateral. The level of mosaicism has an impact on laterality and number of tumors

STRUKTUR KOMUNITAS TUMBUHAN PANTAI DI GILI LABAK KABUPATEN SUMENEP SEBAGAI SUMBER BELAJAR BIOLOGI

Gili Labak is an island by its enticing natural potency. It makes this island as tourist destination in order that it increases local or regional tourists and creates new economic resources. Therefore, due to the reason, it also creates tensions toward environment and coastal ecosystems that affect the structure of plant communities there. This study aims to know variety of plants species, evenness, relative abundance, important value index (IVI) and result of the study as learning source of biology. Additionally, the study used quantitative approach by descriptive research design. Furthermore, the sample of the study is all of coastal plants in Gili Labak which is in the plot. The result of the study represented the highest variety of plants species in Gili Labak coast are found in station 2 (no tourism facilities) with value of 501,15 and more than station 1 (tourism facilities provided) with value of 451,64, by the highest evenness of plants in Gili Labak coast of Sumenep Regency is founded in station 1 (tourism facilities provided) namely Leucaena leucocephala, relative abundance is greatly influenced by physical condition of environment such as air temperature, soil temperature, soil pH and soil texture. Then, the highest IVI of structure of plant communities in Gili Labak coast of Sumenep Regency is Leucaena leucocephala with value 0,85% in station 1 (tourism facilities provided) and 0,87% in station 2 (no tourism facilities). The study of Structure of Plant Communities could be used as learning sources of Biology of Junior High School on “Environmental Changes” subject and as lab modules of Senior High School of X grade on the subject of “Ecology”

Magnetic trapping and coherent control of laser-cooled molecules

We demonstrate coherent microwave control of the rotational, hyperfine and Zeeman states of ultracold CaF molecules, and the magnetic trapping of these molecules in a single, selectable quantum state. We trap about 5 X 10³ molecules for almost 2s at a temperature of 70(8) μK and a density of 1.2 X 10⁵ cm⁻³. We measure the state-specific loss rate due to collisions with background helium

A buffer gas beam source for short, intense and slow molecular pulses

Experiments with cold molecules usually begin with a molecular source. We describe the construction and characteristics of a cryogenic buff er gas source of CaF molecules. The source emits pulses with a typical duration of 240 μs, a mean speed of about 150 m/s, and a flux of 5x 10¹⁰ molecules per steradian per pulse in a single rotational state

New techniques for a measurement of the electron's electric dipole moment

The electric dipole moment of the electron (eEDM) can be measured with high precision using heavy polar molecules. In this paper, we report on a series of new techniques that have improved the statistical sensitivity of the YbF eEDM experiment. We increase the number of molecules participating in the experiment by an order of magnitude using a carefully designed optical pumping scheme. We also increase the detection efficiency of these molecules by another order of magnitude using an optical cycling scheme. In addition, we show how to destabilise dark states and reduce backgrounds that otherwise limit the efficiency of these techniques. Together, these improvements allow us to demonstrate a statistical sensitivity of 1.8 x 10⁻²⁸ e cm after one day of measurement, which is 1.2 times the shot-noise limit. The techniques presented here are applicable to other high-precision measurements using molecules

3D-printed components for quantum devices

Recent advances in the preparation, control and measurement of atomic gases have led to new insights into the quantum world and unprecedented metrological sensitivities, e.g. in measuring gravitational forces and magnetic fields. The full potential of applying such capabilities to areas as diverse as biomedical imaging, non-invasive underground mapping, and GPS-free navigation can only be realised with the scalable production of efficient, robust and portable devices. We introduce additive manufacturing as a production technique of quantum device components with unrivalled design freedom and rapid prototyping. This provides a step change in efficiency, compactness and facilitates systems integration. As a demonstrator we present an ultrahigh vacuum compatible ultracold atom source dissipating less than ten milliwatts of electrical power during field generation to produce large samples of cold rubidium gases. This disruptive technology opens the door to drastically improved integrated structures, which will further reduce size and assembly complexity in scalable series manufacture of bespoke portable quantum devices

Radio-frequency dressed state potentials for neutral atoms

Potentials for atoms can be created by external fields acting on properties like magnetic moment, charge, polarizability, or by oscillating fields which couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here we present an experimental investigation of the remarkable properties of potentials derived from radio-frequency (RF) coupling between electronic ground states. The coupling is magnetic and the vector character allows to design state dependent potential landscapes. On atom chips this enables robust coherent atom manipulation on much smaller spatial scales than possible with static fields alone. We find no additional heating or collisional loss up to densities approaching $10^{15}$ atoms / cm$^3$ compared to static magnetic traps. We demonstrate the creation of Bose-Einstein condensates in RF potentials and investigate the difference in the interference between two independently created and two coherently split condensates in identical traps. All together this makes RF dressing a powerful new tool for micro manipulation of atomic and molecular systems