Remote entanglement between a single atom and a Bose-Einstein condensate.

Entanglement between stationary systems at remote locations is a key resource for quantum networks. We report on the experimental generation of remote entanglement between a single atom inside an optical cavity and a Bose-Einstein condensate (BEC). To produce this, a single photon is created in the atom-cavity system, thereby generating atom-photon entanglement. The photon is transported to the BEC and converted into a collective excitation in the BEC, thus establishing matter-matter entanglement. After a variable delay, this entanglement is converted into photon-photon entanglement. The matter-matter entanglement lifetime of 100 µs exceeds the photon duration by 2 orders of magnitude. The total fidelity of all concatenated operations is 95%. This hybrid system opens up promising perspectives in the field of quantum information.

Lossless state detection of single neutral atoms.

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 µs. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.

Photon-photon entanglement with a single trapped atom.

An experiment is performed where a single rubidium atom trapped within a high-finesse optical cavity emits two independently triggered entangled photons. The entanglement is mediated by the atom and is characterized both by a Bell inequality violation of S=2.5, as well as full quantum-state tomography, resulting in a fidelity exceeding F=90%. The combination of cavity-QED and trapped atom techniques makes our protocol inherently deterministic--an essential step for the generation of scalable entanglement between the nodes of a distributed quantum network.

Fast excitation and photon emission of a single-atom-cavity system.

We report on the fast excitation of a single atom coupled to an optical cavity using laser pulses that are much shorter than all other relevant processes. The cavity frequency constitutes a control parameter that allows the creation of single photons in a superposition of two tunable frequencies. Each photon emitted from the cavity thus exhibits a pronounced amplitude modulation determined by the oscillatory energy exchange between the atom and the cavity. Our technique constitutes a versatile tool for future quantum networking experiments.

Bichromatic slowing and collimation to make an intense helium beam.

The bichromatic force has been used to both slow and collimate a beam of metastable 2(3)S He atoms (He*). The collimation capture range is an extraordinary +/-85 m/s corresponding to approximately 0.18 radians from our source. Both slowing and collimation were accomplished in the unprecedented short distance of approximately 5 cm each. The overall brightness increase is x3200, and there is potential for considerably more.

[Adjuvant gestagen therapy of endometrial carcinoma (author's transl)]. / Die adjuvante Gestagentherapie des Endometriumkarzinoms.

Reference is made in this paper to histological findings, with the view to presenting the results of preoperative gestagen therapy, using hydroxyprogesterone capronate, applied to 334 patients with endometrial carcinomas. Complete tumour regression was achieved in 8.7 per cent of these cases. Further differentiation and increased secretion of the tumour cell were recorded in 56.6 per cent. No gestagen effect at all was recordable from 34.7 per cent only.--Sensitivity of endometrial carcinomas to gestagens was at its highest in cases of highly differentiated adenocarcinomas, in premenopausal women, in the presence of oestrogenic colpocytological reaction, and when endometrial carcinomas coincided with adipositas and diabetes mellitus.--Five-year survival rates, following surgery in combination with hormonal therapy, reached 91,3 per cent and thus were in excess of the 78.6 per cent recorded from patients with surgical treatment alone.

[Significance of the ascorbic acid test in the determination of ovulation in sterility patients]. / Zur Bedeutung des Askorbinsäuretest für die Bestimmung des Ovulationstermins bei Sterilitätspatientinnen.

The study is engaged with the possibility to use ascorbic acid value for better determination of ovulation in sterile patients. We investigated the acid excretion in 8-hour-urinary-portions of 21 patients following daily application of 600 mg ascorbic acid from the 4th to the 20th day of menstrual cycla. Comparing the results to morning temperature, spin--and fern phenomenon of the cervical mucos and biopsy of the endometrium we found the excretion minimum in 61,9% 2 till 3 days before rise of the morning temperature and at the end of the praeovulatory phase. Correlation between ascorbic acid metabolism and ovulation are under discussion.