Heralded Entanglement of Arbitrary Degree in Remote Qubits

Incoherent scattering of photons off two remote atoms with a Lambda-level structure is used as a basic Young-type interferometer to herald long-lived entanglement of an arbitrary degree. The degree of entanglement, as measured by the concurrence, is found to be tunable by two easily accessible experimental parameters. Fixing one of them to certain values unveils an analog to the Malus' law. An estimate of the variation in the degree of entanglement due to uncertainties in an experimental realization is given.Comment: published version, 4 pages and 2 figure

Generation of Total Angular Momentum Eigenstates in Remote Qubits

We propose a scheme enabling the universal coupling of angular momentum of $N$ remote noninteracting qubits using linear optical tools only. Our system consists of $N$ single-photon emitters in a $\Lambda$-configuration that are entangled among their long-lived ground-state qubits through suitably designed measurements of the emitted photons. In this manner, we present an experimentally feasible algorithm that is able to generate any of the $2^N$ symmetric and nonsymmetric total angular momentum eigenstates spanning the Hilbert space of the $N$-qubit compound.Comment: 5 pages, 4 figures, improved presentation. Accepted in Physical Review

A versatile source of polarization-entangled photons

We propose a method for the generation of a large variety of entangled states, encoded in the polarization degrees of freedom of N photons, within the same experimental setup. Starting with uncorrelated photons, emitted from N arbitrary single photon sources, and using linear optical tools only, we demonstrate the creation of all symmetric states, e.g., GHZ- and W-states, as well as all symmetric and non-symmetric total angular momentum eigenstates of the N qubit compound.Comment: 4 pages, 3 figure

Simulating the coupling of angular momenta in distant matter qubits

We present a mathematical proof of the algorithm allowing to generate all - symmetric and non-symmetric - total angular momentum eigenstates in remote matter qubits by projective measurements, proposed in Maser et al. [Phys. Rev. A 79, 033833 (2009)]. By deriving a recursion formula for the algorithm we show that the generated states are equal to the total angular momentum eigenstates obtained via the usual quantum mechanical coupling of angular momenta. In this way we demonstrate that the algorithm is able to simulate the coupling of N spin-1/2 systems, and to implement the required Clebsch-Gordan coefficients, even though the particles never directly interact with each other.Comment: 17 pages, 1 figur

Low-temperature magnetic fluctuations in the Kondo insulator SmB6

We present the results of a systematic investigation of the magnetic properties of the three-dimensional Kondo topological insulator SmB6 using magnetization and muon-spin relaxation/rotation (muSR) measurements. The muSR measurements exhibit magnetic field fluctuations in SmB6 below 15 K due to electronic moments present in the system. However, no evidence for magnetic ordering is found down to 19 mK. The observed magnetism in SmB6 is homogeneous in nature throughout the full volume of the sample. Bulk magnetization measurements on the same sample show consistent behavior. The agreement between muSR, magnetization, and NMR results strongly indicate the appearance of intrinsic bulk magnetic in-gap states associated with fluctuating magnetic fields in SmB6 at low temperature.Comment: 5 pages, 5 figure

Pediatric oncologists' perspectives on the use of complementary medicine in pediatric cancer patients in Switzerland: A national survey-based cross-sectional study

BACKGROUND There is a widespread use of complementary therapies among pediatric cancer patients. Previous studies provided evidence that communication between pediatric oncologists (POs) and patients/families about the use of these therapies is often incomplete. Furthermore, nationwide studies on this topic are rare. AIMS We assessed POs' perspectives on the use of complementary medicine (CM) in Switzerland, on the basis of an edited survey previously used in a nationwide study. METHODS AND RESULTS A link to an online survey was sent by e-mail to each of the fifty-two eligible pediatric oncologists in all nine Swiss Pediatric Oncology Group (SPOG) centers. Eligible respondents were board-certified (Switzerland or abroad) POs currently working at a SPOG center. The survey was available for a total period of 2 months. We received 29 filled questionnaires (overall response rate: 56%). Most POs (59%) indicated that they ask more than 50% of their patients about CM use. Frequent reasons for not asking about the use of CM were i) forgetting to ask (55%), ii) lack of knowledge on the subject (31%), and iii) lack of time (24%). More than every second PO (55%) reported having a lack of knowledge on the subject. A majority of POs (66% to 76%) indicated interest in learning more about specific CM topics (cannabinoids, hypnosis and relaxation, music therapy, herbal medicine, acupuncture, meditation, and yoga). More information and specific training opportunities on the use of CM was deemed important by 76% to 97% of POs. CONCLUSION POs working in Switzerland identify complementary therapies as an important subject. Swiss POs are willing to acquire more knowledge on CM. More training seems to be necessary in order to increase awareness about the topic, to enhance communication about complementary therapies and thus to improve patient care

Pediatric oncologists' perspectives on the use of complementary medicine in pediatric cancer patients in Switzerland: A national survey-based cross-sectional study.

BACKGROUND There is a widespread use of complementary therapies among pediatric cancer patients. Previous studies provided evidence that communication between pediatric oncologists (POs) and patients/families about the use of these therapies is often incomplete. Furthermore, nationwide studies on this topic are rare. AIMS We assessed POs' perspectives on the use of complementary medicine (CM) in Switzerland, on the basis of an edited survey previously used in a nationwide study. METHODS AND RESULTS A link to an online survey was sent by e-mail to each of the fifty-two eligible pediatric oncologists in all nine Swiss Pediatric Oncology Group (SPOG) centers. Eligible respondents were board-certified (Switzerland or abroad) POs currently working at a SPOG center. The survey was available for a total period of 2 months. We received 29 filled questionnaires (overall response rate: 56%). Most POs (59%) indicated that they ask more than 50% of their patients about CM use. Frequent reasons for not asking about the use of CM were i) forgetting to ask (55%), ii) lack of knowledge on the subject (31%), and iii) lack of time (24%). More than every second PO (55%) reported having a lack of knowledge on the subject. A majority of POs (66% to 76%) indicated interest in learning more about specific CM topics (cannabinoids, hypnosis and relaxation, music therapy, herbal medicine, acupuncture, meditation, and yoga). More information and specific training opportunities on the use of CM was deemed important by 76% to 97% of POs. CONCLUSION POs working in Switzerland identify complementary therapies as an important subject. Swiss POs are willing to acquire more knowledge on CM. More training seems to be necessary in order to increase awareness about the topic, to enhance communication about complementary therapies and thus to improve patient care

Projected loss of soil organic carbon in temperate agricultural soils in the 21^stcentury: effects of climate change and carbon input trends

Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21st century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11–16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19–24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3–8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils

A luminosity monitor for the A4 parity violation experiment at MAMI

A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both is required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 hours with electron beam, and the results of its application in the A4 experiment are presented.Comment: 22 pages, 12 figures, submitted to NIM

Broadband Alfvénic excitation correlated to turbulence level in the Wendelstein 7-X stellarator plasmas

During the first operational phase (OP1) of the Wendelstein 7-X (W7-X) stellarator, poloidal magnetic field fluctuations, $\dot{B}_{\theta}$, were measured in several different plasma scenarios with a system of Mirnov coils. In the spectrograms, multiple frequency bands close together in frequency are observed below f = 600 kHz. Furthermore, a dominant feature is the appearance of a frequency band with the highest spectral amplitude centred between $f = 180-220$ kHz. The fluctuations are observed from the beginning of most W7-X plasmas of OP1, which were often operated solely with electron cyclotron resonance heating. The fluctuations show characteristics known from Alfvén waves and possibly Alfvén eigenmodes (AEs). However, the fast particle drive from heating sources, which is generally a driver necessary for the appearance of AEs in magnetic confinement plasmas, is absent in most of the analysed experiments. A characterization of the Alfvénic fluctuations measured during OP1 plasmas is possible using a newly developed tracking algorithm. In this paper, we extensively survey the different spectral properties of the fluctuations in correlation with plasma parameters and discuss possible driving mechanisms. The correlation studies of the dynamics of the possible ellipticity induced AEs indicate that Alfvén activity in the frequency interval between $f = 100-450$ kHz could be excited due to an interaction with turbulence, or profile effects also affecting the turbulence amplitude