224 research outputs found
Continuous Formation of Vibronic Ground State RbCs Molecules via Photoassociation
We demonstrate the direct formation of vibronic ground state RbCs molecules
by photoassociation of ultracold atoms followed by radiative stabilization. The
photoassociation proceeds through deeply-bound levels of the (2)^{3}\Pi_{0^{+}}
state. From analysis of the relevant free-to-bound and bound-to-bound
Franck-Condon factors, we have predicted and experimentally verified a set of
photoassociation resonances that lead to efficient creation of molecules in the
v=0 vibrational level of the X^{1}\Sigma^{+} electronic ground state. We also
compare the observed and calculated laser intensity required to saturate the
photoassociation rate. We discuss the prospects for using short-range
photoassociation to create and accumulate samples of ultracold polar molecules
in their rovibronic ground state.Comment: 15 pages, 7 figure
The impact of supply chain relationships and automatic data communication and registration on forecast information quality
Purpose – The purpose of this paper is to explain the effects of the customer-supplier relationship and of automatic forecast data communication and registration on the perceived information quality of forecasts.
Design/methodology/approach – A conceptual model and three hypotheses are derived. The empirical analysis is based on survey data from 219 Swedish manufacturing companies.
Findings – Findings show that the customer-supplier relationship and automatic data communication
and registration have significant impact on the perceived quality of forecast information received from a
downstream customer in the supply chain. The reliability and timeliness of the forecast information are affected to about the same extent byboth the relationship type andthe data communication andregistration strategy. Credibility is correlated with the relationship type, while the completeness, validity and conciseness of the received forecast are operative issues dependingmainly on the communication strategy.
Research limitations/implications – Using single informants, focal customers and some single-item constructs in research design.
Practical implications – The paper explains how various dimensions of forecast information quality are affected by different factors, thus guiding how to differentiate information quality improvement work in diverse situations.
Originality/value – Detailed empirical studies of supply chain information exchange, especially focusing on explaining causes of high-quality information exchange, are lacking in the literature and demanded in industry
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to tenth order
Deeply bound ultracold molecules in an optical lattice
We demonstrate efficient transfer of ultracold molecules into a deeply bound rovibrational level of the singlet ground state potential in the presence of an optical lattice. The overall molecule creation efficiency is 25%, and the transfer efficiency to the rovibrational level vertical bar v = 73, J = 2 > is above 80%. We find that the molecules in vertical bar v = 73, J = 2 > are trapped in the optical lattice, and that the lifetime in the lattice is limited by optical excitation by the lattice light. The molecule trapping time for a lattice depth of 15 atomic recoil energies is about 20 ms. We determine the trapping frequency by the lattice phase and amplitude modulation technique. It will now be possible to transfer the molecules to the rovibrational ground state vertical bar v = 0, J = 0 > in the presence of the optical lattice
Interference of interacting matter waves
The phenomenon of matter-wave interference lies at the heart of quantum physics. It has been observed in various contexts in the limit of non-interacting particles as a single-particle effect. Here we observe and control matter-wave interference whose evolution is driven by interparticle interactions. In a multi-path matter-wave interferometer, the macroscopic many-body wave function of an interacting atomic Bose-Einstein condensate develops a regular interference pattern, allowing us to detect and directly visualize the effect of interaction-induced phase shifts. We demonstrate control over the phase evolution by inhibiting interaction-induced dephasing and by refocusing a dephased macroscopic matter wave in a spin-echo-type experiment. Our results show that interactions in a many-body system lead to a surprisingly coherent evolution, possibly enabling narrow-band and high-brightness matter-wave interferometers based on atom lasers
Pinning quantum phase transition for a Luttinger liquid of strongly interacting bosons
One of the most remarkable results of quantum mechanics is the fact that
many-body quantum systems may exhibit phase transitions even at zero
temperature. Quantum fluctuations, deeply rooted in Heisenberg's uncertainty
principle, and not thermal fluctuations, drive the system from one phase to
another. Typically, the relative strength of two competing terms in the
system's Hamiltonian is changed across a finite critical value. A well-known
example is the Mott-Hubbard quantum phase transition from a superfluid to an
insulating phase, which has been observed for weakly interacting bosonic atomic
gases. However, for strongly interacting quantum systems confined to
lower-dimensional geometry a novel type of quantum phase transition may be
induced for which an arbitrarily weak perturbation to the Hamiltonian is
sufficient to drive the transition. Here, for a one-dimensional (1D) quantum
gas of bosonic caesium atoms with tunable interactions, we observe the
commensurate-incommensurate quantum phase transition from a superfluid
Luttinger liquid to a Mott-insulator. For sufficiently strong interactions, the
transition is induced by adding an arbitrarily weak optical lattice
commensurate with the atomic granularity, which leads to immediate pinning of
the atoms. We map out the phase diagram and find that our measurements in the
strongly interacting regime agree well with a quantum field description based
on the exactly solvable sine-Gordon model. We trace the phase boundary all the
way to the weakly interacting regime where we find good agreement with the
predictions of the 1D Bose-Hubbard model. Our results open up the experimental
study of quantum phase transitions, criticality, and transport phenomena beyond
Hubbard-type models in the context of ultracold gases
Sub-Millisecond Measurements of Thermal Conductivity and Thermal Diffusivity Using Micrometer-Sized Hot Strips
A new measurement technique based on the transient hot strip technique has recently been developed for studying anisotropic thermal transport properties of thin crystalline films. A micrometer-sized hot strip sensor is evaporated on the surface of the crystalline film sample, which has been deposited on a substrate wafer of limited thickness. From a pulsed transient recording, using sub-millisecond square-shaped pulses, a thermal probing depth that is less than the film thickness is assured. In the ongoing work of verifying the technique, we show results from measurements on z-cut crystal quartz and fused silica, using thermal probing depths of only 30 μm, which closely conform to bulk values found in the literature
Exploring power shifts as an enabler for a strengthened patient role in quality improvements: A Swedish survey study
Objectives This study examined the relationship between professionals\u27 perceptions of a strengthened role for the patient and of patient involvement in quality improvement (QI) and whether professionals\u27 experiences in improvement science were a moderator on such a relationship. Design From a predominantly close-ended, 44-item questionnaire, 4 questions specifically concerning professionals′ perception on patient involvement in QI were analysed. Setting Three Swedish regions. Participants 155 healthcare professionals who had previously participated in courses in improvement science. Results The covariate patient involvement was significantly related to a perceived strengthened patient role. There was also a significant interaction effect between degree of patient involvement and professionals\u27 experience in the area of improvement science on a strengthened patient role. The result shows that there is a relationship between the perceived level of patient involvement in improvements and professionals\u27 perceptions of a strengthened patient role. In this study, the covariate, perceived patient involvement, was significantly related to experiences of more equal relationships between patients and healthcare professionals. There was also a significant interaction effect between the degree of patient involvement and professionals\u27 experience in the area of improvement science, for a more equal relationship between patients and healthcare professionals. Conclusion Increased patient involvement in QI is a means of strengthening the patient role and supporting a more equal relation between patients and healthcare professionals. Furthermore, empirical evidence shows that the healthcare professionals\u27 experiences in the area of improvement science support a strengthened patient role and a more equal power relationship, but for this to happen, the mindset of professionals is key. Future research is needed to capture and investigate the experiences from patients and relatives about being involved in QI in healthcare, and to study the effects on quality in care processes
Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings
In vertically oriented machines with journal bearing, there are no predefined static radial loads, such as dead weight for horizontal rotor. Most of the commercial software is designed to calculate rotordynamic and bearing properties based on machines with a horizontally oriented rotor; that is, the bearing properties are calculated at a static eccentricity. For tilting-pad bearings, there are no existing analytical expressions for bearing parameters and the bearing parameters are dependent on eccentricity and load angle. The objective of this paper is to present a simplified method to perform numerical simulations on vertical rotors including bearing parameters. Instead of recalculating the bearing parameters in each time step polynomials are used to represent the bearing parameters for present eccentricities and load angles. Numerical results are compared with results from tests performed in a test rig. The test rig consists of two guide bearings and a midspan rotor. The guide bearings are 4-pad tilting-pad bearings. Shaft displacement and strains in the bearing bracket are measured to determine the test rig’s properties. The comparison between measurements and simulated results shows small deviations in absolute displacement and load levels, which can be expected due to difficulties in calculating exact bearing parameters
Exploring the phase for highest impact on radicality: a cross-sectional study of patient involvement in quality improvement in Swedish healthcare
Objectives Involving patients in quality improvement is often suggested as a critical step for improving healthcare processes. However, this comes with challenges related to resources, tokenism, validity and competence. Therefore, to optimise the use of available resources, there is a need to understand at what stage in the improvement cycle patient involvement is most beneficial. Thus, the purpose of this study was to identify the phase of an improvement cycle in which patient involvement had the highest impact on radicality of improvement.Design An exploratory cross-sectional survey was used.Setting and methods A questionnaire was completed by 155 Swedish healthcare professionals (response rate 34%) who had trained and had experience in patient involvement in quality improvement. Based on their replies, the impact of patient involvement on radicality in various phases of the improvement cycle was modelled using the partial least squares method.Results Patient involvement in quality improvement might help to identify and realise innovative solutions; however, there is variation in the impact of patient involvement on perceived radicality depending on the phase in which patients become involved. The highest impact on radicality was observed in the phases of capture experiences and taking action, while a moderate impact was observed in the evaluate phase. The lowest impact was observed in the identify and prioritise phase.Conclusions Involving patients in improvement projects can enhance the quality of care and help to identify radically new ways of delivering care. This study shows that it is possible to suggest at what point in an improvement cycle patient involvement has the highest impact, which will enable more efficient use of the resources available for patient involvement
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