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Objective: To assess the impact of a migraine management program offered as a complimentary service by a company within its corporate well‐being program. Background: Migraine imposes a substantial burden on patients, families, employers, and societies. As migraine primarily affects working‐age adults, this has important implications for both employees and employers. Workplace educational and well‐being programs positively contribute to employees' productivity, reduce costs related to absenteeism, and improve the quality of life of the employees living with migraine. Methods: This was a non‐interventional cohort study, which followed employees and their family members over time. Participants received 1 telemedicine consultation to determine migraine diagnosis or a high probability of having migraine and 6 sessions of individualized telecoaching from a specialized nurse via a specially developed smartphone application to optimize their migraine management leveraging all appropriate medical and lifestyle options. Participants were evaluated during the program and at 3 months after completion through a series of validated questionnaires including Migraine Disability Assessment (MIDAS), Patient Activation Measure (PAM), and satisfaction with the services offered. A cost analysis was also performed to determine the economic benefit of the program considering the number of completers, dropouts, their associated program costs, MIDAS data, average salary of a Swiss employee in the pharma sector, and working days per year. Results: Of the 141 participants enrolled in the program, 79 completed 6‐month and 42 completed 9‐month assessments. The total MIDAS scores (mean, standard deviation [SD]) significantly improved from baseline by 54% at Month 6 (15.0 [13.6] vs 6.9 [8.2]; mean [SD] reduction: 8.1 [12.9], 95% confidence interval [CI]: 5.6‐10.6; P <.0001) and by 64% at Month 9 (15.4 [14.7] vs 5.6 [6.0]; mean [SD] reduction: 9.8 [14.0], 95% CI: 6.6‐13.0; P <.0001). The PAM scores also significantly improved from baseline by 8% at Month 6 (63.8 [10.9] vs 69.6 [12.8]; mean [SD] increase: 5.8 [12.8], 95% CI: 3.2‐8.4; P =.003) and 11% at Month 9 (63.5 [10.7] vs 71.3 [12.2]; mean [SD] increase: 7.8 [11.0], 95% CI: 4.3‐11.2; P =.003). At Month 6, common coaching lessons and respective action plans focused on progressive muscle relaxation, sleep, hydration, nutrition, general disease education, and stress management. The exit survey showed that the majority of the participants who completed the program had a meaningful and sustained improvement in their overall health and reported a high level of satisfaction with the program. The cost analysis revealed that on average participants gained 10.8 (95% CI: 9.3‐12.3) working days/year that were previously lost due to migraine, resulting in a positive return on investment (ROI) of 490% (95% CI: 410%‐570%), indicating a higher magnitude of savings that could be achieved by the implementation of such program. In addition to ROI and work productivity gained, participants also gained on average 13.6 (95% CI: 9.9‐17.3) migraine‐free days/year for their private and social life. Conclusion: The employer‐sponsored disease management program provided a better understanding of migraine, promoted methods and approaches to improve management by combining medical and lifestyle options leading to significant improvements in migraine symptoms that sustained beyond the intervention, supporting prolonged effectiveness of such programs. The program also provided a high ROI to the employer, supporting that the systematic inclusion of such programs into corporate well‐being initiatives can be of significant benefit not only to the impacted individuals but to the employers as well. [ABSTRACT FROM AUTHOR]

Purpose. To develop generic optimization strategies for image reconstruction using graphical processing units (GPUs) in magnetic resonance imaging (MRI) and to exemplarily report on our experience with a highly accelerated implementation of the nonlinear inversion (NLINV) algorithm for dynamic MRI with high frame rates. Methods. The NLINV algorithm is optimized and ported to run on a multi-GPU single-node server. The algorithm is mapped to multiple GPUs by decomposing the data domain along the channel dimension. Furthermore, the algorithm is decomposed along the temporal domain by relaxing a temporal regularization constraint, allowing the algorithm to work on multiple frames in parallel. Finally, an autotuning method is presented that is capable of combining different decomposition variants to achieve optimal algorithm performance in different imaging scenarios. Results. The algorithm is successfully ported to a multi-GPU system and allows online image reconstruction with high frame rates. Real-time reconstruction with low latency and frame rates up to 30 frames per second is demonstrated. Conclusion. Novel parallel decomposition methods are presented which are applicable to many iterative algorithms for dynamic MRI. Using these methods to parallelize the NLINV algorithm on multiple GPUs, it is possible to achieve online image reconstruction with high frame rates. [ABSTRACT FROM AUTHOR]

The endeavour to control increasingly larger systems of particles at the quantum level is a natural goal, and will be a driving force for the physical sciences in the coming decades. The control of a many-body system at the highest level possible can indeed be regarded as the ultimate form of engineering. Within this general research avenue, building quantum simulators and performing experimental quantum simulations will play a key role. A quantum simulator is a promising candidate to become the first application of quantum information science reaching beyond classical limitations [1], since the requirements on the number of quantum particles and fidelities of operations are predicted to be substantially relaxed compared to that envisioned for a universal quantum computer. This issue forms an extensive open-access resource spanning the various areas of experimental quantum simulation, from its relation to quantum information processing to its potential use for different applications. [ABSTRACT FROM AUTHOR]

We introduce a scheme to perform dissipation-assisted quantum information processing in ion traps considering realistic decoherence rates, for example, due to motional heating. By means of continuous sympathetic cooling, we overcome the trap heating by showing that the damped vibrational excitations can still be exploited to mediate coherent interactions as well as collective dissipative effects. We describe how to control their relative strength experimentally, allowing for protocols of coherent or dissipative generation of entanglement. This scheme can be scaled to larger ion registers for coherent or dissipative many-body quantum simulations. [ABSTRACT FROM AUTHOR]

We describe a versatile toolbox for the quantum simulation of manybody lattice models, capable of exploring the combined effects of background Abelian and non-Abelian gauge fields, bond and site disorder and strong onsite interactions. We show how to control the quantum dynamics of particles trapped in lattice potentials by the photon-assisted tunneling induced by periodic drivings. This scheme is general enough to be applied to either bosons or fermions with the additional advantage of being non-perturbative. It finds an ideal application in microfabricated ion trap arrays, where the quantized vibrational modes of the ions can be described by a quantum lattice model. We present a detailed theoretical proposal for a quantum simulator in that experimental setup, and show that it is possible to explore phases of matter that range from the fractional quantum Hall effect, to exotic strongly correlated glasses or flux-lattice models decorated with arbitrary patterns of localized defects. [ABSTRACT FROM AUTHOR]

Abstract: Concentrating dilute streams is a key operation in numerous industries. The work presented here investigates the use of magnetic nanoparticles as transport reagents to mechanically move specific compounds against concentration gradients. Using a model system (arsenate), a cyclic, two-step process for concentrating solutes can be realized, based on a reversible, pH dependent adsorption equilibrium and two stirred tanks: adsorption of the model ion As(V) from a dilute aqueous stream (large tank) onto chemically functionalized magnetic nanoparticles allows water purification at the mg per liter level. Magnetic separation thereby results in an energy efficient removal of the noxious ion from a large water volume (no pumping, magnetic sedimentation/flocculation) and transfer into a much smaller, separate volume (small tank). Changing the acidity (pH) within the much smaller tank allows desorption of the collected ion As(V) into a small volume and thereby permits efficient enrichment. This process scheme, therefore, splits a highly dilute stream into a purified stream (A) and a concentrate stream (B) by using a true moving bed. Long time recycling of the functional magnetic nanoparticles mainly depends on the efficiency of magnetic filtration, under the conditions of reversible adsorption and by using stable magnetic nanoparticles (carbon-coated metal nanoparticles). [Copyright &y& Elsevier]

The vibrations of a collection of ions in a microtrap array can be described in terms of tunneling phonons. We show that the vibrational couplings may be tailored by using a gradient of the trap frequencies together with a periodic driving of the trapping potentials. These ingredients allow us to induce effective gauge fields on the vibrational excitations, such that phonons mimic the behavior of charged particles in a magnetic field. In particular, microtrap arrays are well suited to realize a quantum simulator of the famous Aharonov-Bohm effect and observe the paradigmatic edge states typical from quantum-Hall samples and topological insulators. [ABSTRACT FROM AUTHOR]

Abstract: Previous studies have indicated a paucity of SINEs within the genomes of the guinea pig and nutria, representatives of the Hystricognathi suborder of rodents. More recent work has shown that the guinea pig genome contains a large number of B1 elements, expanding to various levels among different rodents. In this work we utilized A–B PCR and screened GenBank with sequences from isolated clones to identify potentially uncharacterized SINEs within the guinea pig genome, and identified numerous sequences with a high degree of similarity (>92%) specific to the guinea pig. The presence of A-tails and flanking direct repeats associated with these sequences supported the identification of a full-length SINE, with a consensus sequence notably distinct from other rodent SINEs. Although most similar to the ID SINE, it clearly was not derived from the known ID master gene (BC1), hence we refer to this element as guinea pig ID-like (GPIDL). Using the consensus to screen the guinea pig genomic database (Assembly CavPor2) with Ensembl BlastView, we estimated at least 100,000 copies, which contrasts markedly to just over 100 copies of ID elements. Additionally we provided evidence of recent integrations of GPIDL as two of seven analyzed conserved GPIDL-containing loci demonstrated presence/absence variants in Cavia porcellus and C. aperea. Using intra-IDL PCR and sequence analyses we also provide evidence that GPIDL is derived from a hystricognath-specific SINE family. These results demonstrate that this SINE family continues to contribute to the dynamics of genomes of hystricognath rodents. [Copyright &y& Elsevier]

Experiments directed towards the development of an analogue quantum simulator based on trapped atomic magnesium ions are described. We report on the required initialization including ground state cooling of 25Mg+ ions for the first time - parallel to the group at NIST/Boulder. We discuss basic operations to implement quantum spin Hamiltonians like a one-dimensional quantum Ising model and some challenges to be addressed in reaching for larger scale and higher dimensional devices. [ABSTRACT FROM AUTHOR]

To assess participants' satisfaction with a Migraine Care program offered by a healthcare company as a complimentary service within its wellness program for its Swiss-based employees and their family members. When prompted for self-reported progress towards migraine goals and how the program helped them to better manage their migraine, 77% and 85% responded in favor of the program. Conclusions The results demonstrate that an employer-sponsored migraine disease management program resulted in greater clinical improvements in employees' migraine and very high levels of satisfaction with the program informing other companies that such programs could be great enhancements of their wellness programs. [Extracted from the article]

We describe the concept and experimental demonstration of the basic building blocks of a scalable quantum computer using trapped-ion qubits. The trap structure is divided into subregions where ion qubits can either be held as memory or subjected to individual rotations and multi-qubit gates in processor zones. Thus, ion qubits can become entangled in one trapping zone, then separated and distributed to separate zones (by switching control-electrode potentials) where subsequent single- and two-ion gates, and/or detection is performed. Recent work using these building blocks includes (1) demonstration of a dense-coding protocol, (2) demonstration of enhanced qubit-detection efficiency using quantum logic, (3) generation of GHZ states and their application to enhanced precision in spectroscopy, and (4) the realization of teleportation with atomic qubits. In the final section an analog quantum computer that could provide a shortcut towards quantum simulations under requirements less demanding than those for a universal quantum computer is also described. [ABSTRACT FROM AUTHOR]

Hybrid atom-ion systems are a rich and powerful platform for studying chemical reactions, as they feature both excellent control over the electronic state preparation and readout as well as a versatile tunability over the scattering energy, ranging from the few-partial wave regime to the quantum regime. In this work, we make use of these excellent control knobs, and present a joint experimental and theoretical study of the collisions of a single 138Ba+ ion prepared in the 5 d 2 D 3 / 2 , 5 / 2 metastable states with a ground state 6Li gas near quantum degeneracy. We show that in contrast to previously reported atom-ion mixtures, several non-radiative processes, including charge exchange, excitation exchange and quenching, compete with each other due to the inherent complexity of the ion-atom molecular structure. We present a full quantum model based on high-level electronic structure calculations involving spin-orbit couplings. Results are in excellent agreement with observations, highlighting the strong coupling between the internal angular momenta and the mechanical rotation of the colliding pair, which is relevant in any other hybrid system composed of an alkali-metal atom and an alkaline-earth ion. [ABSTRACT FROM AUTHOR]

Wild bees can be essential pollinators in natural, agricultural, and urban systems, but populations of some species have declined. Efforts to assess the status of wild bees are hindered by uncertainty in common sampling methods, such as pan traps and aerial netting, which may or may not provide a valid index of abundance across species and habitats. Mark-recapture methods are a common and effective means of estimating population size, widely used in vertebrates but rarely applied to bees. Here we review existing mark-recapture studies of wild bees and present a new case study comparing mark-recapture population estimates to pan trap and net capture for four taxa in a wild bee community. Net, but not trap, capture was correlated with abundance estimates across sites and taxa. Logistical limitations ensure that mark-recapture studies will not fully replace other bee sampling methods, but they do provide a feasible way to monitor selected species and measure the performance of other sampling methods. [ABSTRACT FROM AUTHOR]

Isolating neutral and charged particles from the environment is essential in precision experiments. For decades, this has been achieved by trapping ions with radio-frequency (RF) fields and neutral particles with optical fields. Recently, the trapping of ions by interaction with light has been demonstrated. This might permit the advantages of optical trapping and ions to be combined. For example, we would benefit from superimposing optical traps to investigate ensembles of ions and atoms in the absence of any RF fields and from the versatile and scalable trapping geometries featured by optical lattices. In particular, ions provide individual addressability, and electronic and motional degrees of freedom that can be coherently controlled and detected via high-fidelity, state-dependent operations. Their long-range Coulomb interaction is significantly larger compared to those of neutral atoms and molecules. This enables ultra-cold interaction and the chemistry of trapped ions and atoms to be studied, as well as providing a novel platform for higher-dimensional experimental quantum simulations. The aim of this topical review is to present the current state of the art and to discuss the current challenges and prospects of the emerging field. [ABSTRACT FROM AUTHOR]

We introduce a theoretical scheme that exploits laser cooling and phonon-mediated spin–spin interactions in crystals of trapped atomic ions to explore the transport of energy through a quantum magnet. We show how to implement an effective transport window to control the flow of energy through the magnet even in the absence of fermionic statistics for the carriers. This is achieved by shaping the density of states of the effective thermal reservoirs that arise from the interaction with the external bath of the modes of the electromagnetic field, and can be experimentally controlled by tuning the laser frequencies and intensities appropriately. The interplay of this transport window with the spin–spin interactions is exploited to build an analogue of the Coulomb-blockade effect in nano-scale electronic devices, and opens new possibilities to study quantum effects in energy transport. [ABSTRACT FROM AUTHOR]

Review: 212 refs. [ABSTRACT FROM AUTHOR]

To determine the influence of human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T cells on the development of drug resistance mutations in the HIV-1 protease, we analyzed protease sequences from viruses from a human leukocyte antigen class I (HLA class I)-typed cohort of 94 HIV-1-positive individuals. In univariate statistical analyses (Fisher's exact test), minor and major drug resistance mutations as well as drug-associated polymorphisms showed associations with HLA class I alleles. All correlations with P values of 0.05 or less were considered to be relevant without corrections for multiple tests. A subset of these observed correlations was experimentally validated by enzyme-linked immunospot assays, allowing the definition of 10 new epitopes recognized by CD8+ T cells from patients with the appropriate HLA class I type. Several drug resistance-associated mutations in the protease acted as escape mutations; however, cells from many patients were still able to generate CD8+ T cells targeting the escape mutants. This result presumably indicates the usage of different T-cell receptors by CD8+ T cells targeting these epitopes in these patients. Our results support a fundamental role for HLA class I-restricted immune responses in shaping the sequence of the HIV-1 protease in vivo. This role may have important clinical implications both for the understanding of drug resistance pathways and for the design of therapeutic vaccines targeting drug-resistant HIV-1. [ABSTRACT FROM AUTHOR]

Laser-cooled and trapped ions can crystallize and feature discrete solitons that are nonlinear, topologically protected configurations of the Coulomb crystal. Such solitons, as their continuum counterparts, can move within the crystal, while their discreteness leads to the existence of a gap-separated, spatially localized motional mode of oscillation above the spectrum. Suggesting that these unique properties of discrete solitons can be used for generating entanglement between different sites of the crystal, we study a detailed proposal in the context of state-of-the-art experimental techniques. We analyze the interaction of periodically driven planar ion crystals with optical forces, revealing the effects of micromotion in radio-frequency traps inherent to such structures, as opposed to linear ion chains. The proposed method requires Doppler cooling of the crystal and sideband cooling of the soliton's localized modes alone. Since the gap separation of the latter is nearly independent of the crystal size, this approach could be particularly useful for producing entanglement and studying system-environment interactions in large, two- and possibly three-dimensional systems. [ABSTRACT FROM AUTHOR]

We present the preparation and deterministic delivery of a selectable number of externally cold molecular ions. A laser cooled ensemble of Mg ions subsequently confined in several linear Paul traps inter-connected via a quadrupole guide serves as a cold bath for a single or up to a few hundred molecular ions. Sympathetic cooling embeds the molecular ions in the crystalline structure. MgH ions that serve as a model system for a large variety of other possible molecular ions, are cooled down close to the Doppler limit and are positioned with an accuracy of one micrometer. After the production process, severely compromising the vacuum conditions, the molecular ion is efficiently transferred into nearly background-free environment. The transfer of a molecular ion between different traps as well as the control of the molecular ions in the traps is demonstrated. Schemes, optimized for the transfer of a specific number of ions, are realized and their efficiencies are evaluated. This versatile source applicable for broad charge-to-mass ratios of externally cold and precisely positioned molecular ions can serve as a container-free target preparation device well suited for diffraction or spectroscopic measurements on individual molecular ions at high repetition rates (kHz). [ABSTRACT FROM AUTHOR]

Two efficient and isotope-selective resonant two-photon ionization techniques for loading barium ions into radio-frequency (RF)-traps are demonstrated. The scheme of using the strong dipole-allowed transition 6 s S→6 s6 p P at λ=553 nm as a first step towards ionization is compared to the established technique of using a weak inter-combination line (6 s S→5 d6 p D, λ=413 nm). An increase of two orders of magnitude in the ionization efficiency is found favoring the transition at 553 nm. This technique can be implemented using commercial all-solid-state laser systems and is expected to be advantageous compared to other narrowband photo-ionization schemes of barium in cases where highest efficiency and isotope-selectivity are required. [ABSTRACT FROM AUTHOR]

Direct experimental access to some of the most intriguing quantum phenomena is not granted due to the lack of precise control of the relevant parameters in their naturally intricate environment. Their simulation on conventional computers is impossible, since quantum behaviour arising with superposition states or entanglement is not efficiently translatable into the classical language. However, one could gain deeper insight into complex quantum dynamics by experimentally simulating the quantum behaviour of interest in another quantum system, where the relevant parameters and interactions can be controlled and robust effects detected sufficiently well. Systems of trapped ions provide unique control of both the internal (electronic) and external (motional) degrees of freedom. The mutual Coulomb interaction between the ions allows for large interaction strengths at comparatively large mutual ion distances enabling individual control and readout. Systems of trapped ions therefore exhibit a prominent system in several physical disciplines, for example, quantum information processing or metrology. Here, we will give an overview of different trapping techniques of ions as well as implementations for coherent manipulation of their quantum states and discuss the related theoretical basics. We then report on the experimental and theoretical progress in simulating quantum many-body physics with trapped ions and present current approaches for scaling up to more ions and more-dimensional systems. [ABSTRACT FROM AUTHOR]

Scalable quantum computation and communication require error control to protect quantum information against unavoidable noise. Quantum error correction protects information stored in two-level quantum systems (qubits) by rectifying errors with operations conditioned on the measurement outcomes. Error-correction protocols have been implemented in nuclear magnetic resonance experiments, but the inherent limitations of this technique prevent its application to quantum information processing. Here we experimentally demonstrate quantum error correction using three beryllium atomic-ion qubits confined to a linear, multi-zone trap. An encoded one-qubit state is protected against spin-flip errors by means of a three-qubit quantum error-correcting code. A primary ion qubit is prepared in an initial state, which is then encoded into an entangled state of three physical qubits (the primary and two ancilla qubits). Errors are induced simultaneously in all qubits at various rates. The encoded state is decoded back to the primary ion one-qubit state, making error information available on the ancilla ions, which are separated from the primary ion and measured. Finally, the primary qubit state is corrected on the basis of the ancillae measurement outcome. We verify error correction by comparing the corrected final state to the uncorrected state and to the initial state. In principle, the approach enables a quantum state to be maintained by means of repeated error correction, an important step towards scalable fault-tolerant quantum computation using trapped ions. [ABSTRACT FROM AUTHOR]

Over the past half-century, ultrasound imaging has become a key technology for assessing an ever-widening range of medical conditions at all stages of life. Despite ultrasound's proven value, expensive systems that require domain expertise in image acquisition and interpretation have limited its broad adoption. The proliferation of portable and low-cost ultrasound imaging can improve global health and also enable broad clinical and academic studies with great impact on the fields of medicine. Here, we describe the design of a complete ultrasound-on-chip, the first to be cleared by the Food and Drug Administration for 13 indications, comprising a two-dimensional array of silicon-based microelectromechanical systems (MEMS) ultrasonic sensors directly integrated into complementary metal-oxide-semiconductor-based control and processing electronics to enable an inexpensive whole-body imaging probe. The fabrication and design of the transducer array with on-chip analog and digital circuits, having an operating power consumption of 3 W or less, are described, in which approximately 9,000 sevenlevel feedback-based pulsers are individually addressable to each MEMS element and more than 11,000 amplifiers, more than 1,100 analog-to-digital converters, and more than 1 trillion operations per second are implemented. We quantify the measured performance and the ability to image areas of the body that traditionally takes three separate probes. Additionally, two applications of this platform are described--augmented reality assistance that guides the user in the acquisition of diagnostic-quality images of the heart and algorithms that automate the measurement of cardiac ejection fraction, an indicator of heart health. [ABSTRACT FROM AUTHOR]

Quantum teleportation provides a means to transport quantum information efficiently from one location to another, without the physical transfer of the associated quantum-information carrier. This is achieved by using the non-local correlations of previously distributed, entangled quantum bits (qubits). Teleportation is expected to play an integral role in quantum communication and quantum computation. Previous experimental demonstrations have been implemented with optical systems that used both discrete and continuous variables, and with liquid-state nuclear magnetic resonance. Here we report unconditional teleportation of massive particle qubits using atomic (9Be+) ions confined in a segmented ion trap, which aids individual qubit addressing. We achieve an average fidelity of 78 per cent, which exceeds the fidelity of any protocol that does not use entanglement. This demonstration is also important because it incorporates most of the techniques necessary for scalable quantum information processing in an ion-trap system. [ABSTRACT FROM AUTHOR]

The precision in spectroscopy of any quantum system is fundamentally limited by the Heisenberg uncertainty relation for energy and time. For N systems, this limit requires that they be in a quantum-mechanically entangled state. We describe a scalable method of spectroscopy that can potentially take full advantage of entanglement to reach the Heisenberg limit and has the practical advantage that the spectroscopic information is transferred to states with optimal protection against readout noise. We demonstrate our method experimentally with three beryllium ions. The spectroscopic sensitivity attained is 1.45(2) times as high as that of a perfect experiment with three nonentangled particles. [ABSTRACT FROM AUTHOR]

We study a method for mass-selective removal of ions from a Paul trap by parametric excitation. This can be achieved by applying an oscillating electric quadrupole field at twice the secular frequency ω sec using pairs of opposing electrodes. While excitation near the resonance with the secular frequency ω sec only leads to a linear increase of the amplitude with excitation duration, parametric excitation near 2 ω sec results in an exponential increase of the amplitude. This enables efficient removal of ions from the trap with modest excitation voltages and narrow bandwidth, therefore, substantially reducing the disturbance of ions with other charge-to-mass ratios. We numerically study and compare the mass selectivity of the two methods. In addition, we experimentally show that the barium isotopes with 136 and 137 nucleons can be removed from small ion crystals and ejected out of the trap while keeping 138 Ba + ions Doppler cooled, corresponding to a mass selectivity of better than Δ m / m = 1 / 138 . This method can be widely applied to ion trapping experiments without major modifications since it only requires modulating the potential of the ion trap. [ABSTRACT FROM AUTHOR]

Many phenomena described in relativistic quantum field theory are inaccessible to direct observations, but analogue processes studied under well-defined laboratory conditions can present an alternative perspective. Recently, we demonstrated an analogy of particle creation using an intrinsically robust motional mode of two trapped atomic ions. Here, we substantially extend our classical control techniques by implementing machine-learning strategies in our platform and, consequently, increase the accessible parameter regime. As a proof of methodology, we present experimental results of multiple quenches and parametric modulation of an unprotected motional mode of a single ion, demonstrating the increased level of real-time control. In combination with previous results, we enable future experiments that may yield entanglement generation using a process in analogy to Hawking radiation. [ABSTRACT FROM AUTHOR]

Wepropose a method to simulate the dynamics of spin-boson models with small crystals of trapped ions where the electronic degree of freedom of one ion is used to encode the spin while the collective vibrational degrees of freedom are employed to form an effective harmonic environment. The key idea of our approach is that a single damped mode can be used to provide a harmonic environment with Lorentzian spectral density. More complex spectral functions can be tailored by combining several individually damped modes. The protocol is especially well-suited to simulate spin-boson models with structured environments. Wepropose to work with mixed-species crystals such that one species serves to encode the spin while the other species is used to cool the vibrational degrees of freedom to engineer the environment. The strength of the dissipation on the spin can be controlled by tuning the coupling between spin and vibrational degrees of freedom. In this way the dynamics of spin-boson models with macroscopic and non-Markovian environments can be simulated using only a few ions. Weillustrate the approach by simulating an experiment with realistic parameters and show by computing quantitative measures that the dynamics is genuinely non-Markovian. [ABSTRACT FROM AUTHOR]

Aim To evaluate the potential of real-time phase-contrast flow magnetic resonance imaging (MRI) at 40 ms resolution for the simultaneous determination of blood flow in the ascending aorta (AA) and superior vena cava (SVC) in response to reduced intrathoracic pressure (Mueller manoeuvre). Materials and methods Through-plane flow was assessed in 20 healthy young subjects using real-time phase-contrast MRI based on highly undersampled radial fast low-angle shot (FLASH) with image reconstruction by regularized non-linear inversion. Haemodynamic alterations (three repetitions per subject = 60 events) were evaluated during normal breathing (10 s), inhalation with nearly closed epiglottis (10 s), and recovery (20 s). Results Relative to normal breathing and despite interindividual differences, reduced intrathoracic pressure by at least 30 mmHg significantly decreased the initial peak mean velocity (averaged across the lumen) in the AA by −24 ± 9% and increased the velocity in the SVC by +28 ± 25% ( p < 0.0001, n = 23 successful events). Respective changes in flow volume per heartbeat were −25 ± 9% in the AA and +49 ± 44% in the SVC ( p < 0.0001, n = 23). Flow parameters returned to baseline during sustained pressure reduction, while the heart rate was elevated by 10% ( p < 0.0001) after the start ( n = 24) and end ( n = 17) of the manoeuvre. Conclusions Real-time flow MRI during low intrathoracic pressure non-invasively revealed quantitative haemodynamic adjustments in both the AA and SVC. [ABSTRACT FROM AUTHOR]

We describe a high-resolution spectroscopy method in which the detection of single excitation events is enhanced by a complete loss of coherence of a superposition of two ground states. Thereby, transitions of a single isolated atom nearly at rest are recorded efficiently with high signal-to-noise ratios. Spectra display symmetric line shapes without stray-light background from spectroscopy probes. We employ this method on a 25Mg+ ion to measure one-, two-, and three-photon transition frequencies from the 3S ground state to the 3P, 3D, and AP excited states, respectively. Our results are relevant for astrophysics and searches for drifts of fundamental constants. Furthermore, the method can be extended to other transitions, isotopes, and species. The currently achieved fractional frequency uncertainty of 5 × 10-9 is not limited by the method. [ABSTRACT FROM AUTHOR]

We study discrete solitons (kinks) accessible in the state-of-theart trapped ion experiments, considering zigzag crystals and quasi-threedimensional configurations, both theoretically and experimentally. We first extend the theoretical understanding of different phenomena predicted and recently experimentally observed in the structure and dynamics of these topological excitations. Employing tools from topological degree theory, we analyze bifurcations of crystal configurations in dependence on the trapping parameters, and investigate the formation of kink configurations and the transformations of kinks between different structures. This allows us to accurately define and calculate the effective potential experienced by solitons within the Wigner crystal, and study how this (so-called Peierls-Nabarro) potential gets modified to a non-periodic globally trapping potential in certain parameter regimes. The kinks' rest mass (energy) and spectrum of modes are computed and the dynamics of linear and nonlinear kink oscillations are analyzed. We also present novel, experimentally observed, configurations of kinks incorporating a large-mass defect realized by an embedded molecular ion, and of pairs of interacting kinks stable for long times, offering the perspective for exploring and exploiting complex collective nonlinear excitations, controllable on the quantum level. [ABSTRACT FROM AUTHOR]

We study experimentally and theoretically structural defects which are formed during the transition from a laser cooled cloud to a Coulomb crystal, consisting of tens of ions in a linear radio frequency trap. We demonstrate the creation of predicted topological defects ("kinks") in purely two-dimensional crystals and also find kinks which show novel dynamical features in a regime of parameters not considered before. The kinks are always observed at the center of the trap, showing a large nonlinear localized excitation, and the probability of their occurrence saturates at ~0.5. Simulations reveal a strong anharmonicity of the kink's internal mode of vibration, due to the kink's extension into three dimensions. As a consequence, the periodic Peierls-Nabarro potential experienced by a discrete kink becomes a globally confining potential, capable of trapping one cooled defect at the center of the crystal. [ABSTRACT FROM AUTHOR]

Quantum walks have by now been realized in a large variety of different physical settings. In some of these, particularly with trapped ions, the walk is implemented in phase space, where the corresponding position states are not orthogonal. We develop a general description of such a quantum walk and show how to map it into a standard one with orthogonal states, thereby making available all the tools developed for the latter. This enables a variety of experiments, which can be implemented with smaller step sizes and more steps. Tuning the nonorthogonality allows for an easy preparation of extended states such as momentum eigenstates, which travel at a well-defined speed with low dispersion. We introduce a method to adjust their velocity by momentum shifts, which allows us to experimentally probe the dispersion relation, providing a benchmarking tool for the quantum walk, and to investigate intriguing effects such as the analog of Bloch oscillations. [ABSTRACT FROM AUTHOR]

We report on three-dimensional optical trapping of single ions in a one-dimensional optical lattice formed by two counterpropagating laser beams. We characterize the trapping parameters of the standing- wave using the ion as a sensor stored in a hybrid trap consisting of a radio-frequency (rf), a dc, and the optical potential. When loading ions directly from the rf into the standing-wave trap, we observe a dominant heating rate. Monte Carlo simulations confirm rf-induced parametric excitations within the deep optical lattice as the main source. We demonstrate a way around this effect by an alternative transfer protocol which involves an intermediate step of optical confinement in a single-beam trap avoiding the temporal overlap of the standing-wave and the ri field. Implications arise for hybrid (rf-optical) and pure optical traps as platforms for ultracold chemistry experiments exploring atom-ion collisions or quantum simulation experiments with ions, or combinations of ions and atoms. [ABSTRACT FROM AUTHOR]

Trapping and laser cooling in atomic physics enables control of single particles and their dynamics at the quantum level in a background-free environment. Ultrashort intense laser pulses reveal the ultimate control of electromagnetic fields, enabling the imaging of matter, in principle down to a single molecule or virus resolved on atomic scales. However, current methods fall short in overlapping each target with a pulse of comparable size. We combine the two fields by demonstrating a deterministic molecular conveyor, formed of electric trapping potentials. We deliver individual diatomic ions at millikelvin temperatures and with submicrometre positioning into few-femtosecond ultraviolet laser pulses. We initiate and probe the molecule's femtosecond dynamics and detect it and its response with 100% efficiency. This experiment might become key for investigations of individual molecules, such as structural determinations using few-femtosecond X-ray lasers. Our scheme may overlap each single molecule with a pulse, focused to (sub)micrometre size, providing the required number of photons at the repetition rate of the laser. [ABSTRACT FROM AUTHOR]

We examine the prospects of discrete quantum walks (QWs) with trapped ions. In particular, we analyze in detail the limitations of the protocol of Travaglione and Milburn (2002 Phys. Rev. A 65 032310) that has been implemented by several experimental groups in recent years. Based on the first realization in our group (Schmitz et al 2009 Phys. Rev. Lett. 103 090504), we investigate the consequences of leaving the scope of the approximations originally made, such as the Lamb-Dicke approximation. We explain the consequential deviations from the idealized QW for different experimental realizations and an increasing number of steps by taking into account higherorder terms of the quantum evolution. It turns out that these already become significant after a few steps, which is confirmed by experimental results and is currently limiting the scalability of this approach. Finally, we propose a new scheme using short laser pulses, derived from a protocol from the field of quantum computation. We show that this scheme is not subject to the abovementioned restrictions and analytically and numerically evaluate its limitations, based on a realistic implementation with our specific setup. Implementing the protocol with state-of-the-art techniques should allow for substantially increasing the number of steps to 100 and beyond and should be extendable to higher-dimensional QWs. [ABSTRACT FROM AUTHOR]

Isolating ions and atoms from the environment is essential in experiments on a quantum level. For decades, this has been achieved by trapping ions with radiofrequency fields and neutral particles with optical fields. Here we demonstrate the trapping of an ion by interaction with light. The lifetime in the optical trap is several milliseconds, allowing hundreds of oscillations in the optical potential, and could be enhanced by established methods. These results could form the starting point for combining the advantages of optical trapping and ions. Extending the approach to optical lattices could support developments in experimental quantum simulations. As well as simulating complex spin systems with trapped ions, a new class of quantum simulations could be enabled that combines atoms and ions in a common lattice (Cirac, J.I., personal communication; Zoller, P., personal communication). Furthermore, ions could be embedded into quantum degenerate gases, thereby avoiding the inevitable excess kinetic energy of ions in radiofrequency traps, which currently limits cold-chemistry experiments. [ABSTRACT FROM AUTHOR]

We cannot translate quantum behavior arising with superposition states or entanglement efficiently into the classical language of conventional computers (Feynman et al. in Int. J. Theor. Phys. 21:467, ). A universal quantum computer could describe and help to understand complex quantum systems. But it is envisioned to become functional only within the next decade(s). A shortcut was proposed via simulating the quantum behavior of interest in another quantum system, where all relevant parameters and interactions can be controlled and observables of interest detected sufficiently well. For example simulating quantum spin systems within an architecture of trapped ions (Porras and Cirac in Phys. Rev. Lett. 92:207901, ). Here we specify how we simulate the spin and all necessary interactions and how we calibrate their amplitudes. For example via a two-ion phase-gate operation on two axial motional modes simultaneously at a fidelity exceeding 95%. We explain the complete mode of operation of a quantum simulator on the basis of our simple model case—the proof of principle experiment of simulating the transition of a quantum magnet from paramagnetic into entangled ferromagnetic order (Friedenauer et al. in Nat. Phys. 4:757, ) and emphasize some of the similarities and differences with a quantum computer. [ABSTRACT FROM AUTHOR]

To gain deeper insight into the dynamics of complex quantum systems we need a quantum leap in computer simulations. We cannot translate quantum behaviour arising from superposition states or entanglement efficiently into the classical language of conventional computers. The solution to this problem, proposed in 1982 (ref. 1), is simulating the quantum behaviour of interest in a different quantum system where the interactions can be controlled and the outcome detected sufficiently well. Here we study the building blocks for simulating quantum spin Hamiltonians with trapped ions. We experimentally simulate the adiabatic evolution of the smallest non-trivial spin system from paramagnetic into ferromagnetic order with a quantum magnetization for two spins of 98%. We prove that the transition is not driven by thermal fluctuations but is of quantum-mechanical origin (analogous to quantum fluctuations in quantum phase transitions). We observe a final superposition state of the two degenerate spin configurations for the ferromagnetic order (|↑↑〉+|↓↓〉), corresponding to deterministic entanglement achieved with 88% fidelity. This method should allow for scaling to a higher number of coupled spins, enabling implementation of simulations that are intractable on conventional computers. [ABSTRACT FROM AUTHOR]

To perform a return-on-investment (ROI) analysis of a migraine tele-medicine disease management program, sponsored by a company within its wellness program for its Swiss-based employees and their family members, to foster patient empowerment to multidisciplinary approaches in the management of their migraine. Conclusions This analysis concludes that the migraine disease management program has a high ROI informing other employers that the systematic inclusion of migraine management into corporate health management programs can be of significant benefit to the impacted individuals as well as the companies. [Extracted from the article]

BACKGROUND: The purpose of this study was to assess whether, even within a normal FSH range (≤10 mU/ml), age-specific FSH levels are predictive of ovarian reserve. METHODS: Between January 1998 and December 2001, 535 women, undergoing controlled ovarian stimulation with 225 IU of recombinant (rec) FSH and 75 IU of recLH, were included in this retrospective cohort study. Criteria for enrolment were: age 25–40 years, basal FSH (b-FSH) ≤10 mU/ml and basal LH ≤12 mU/ml. Patients were assigned to three age groups (group I: 25–29 years; group II: 30–35 years; and group III: 36–40 years). Each age group was divided into quartiles according to b-FSH levels, comparing the lowest and highest b-FSH quartiles for basal hormonal patterns and outcome-related parameters. RESULTS: At ages 25–35 years, women in the lowest FSH quartiles demonstrated significantly increased numbers of oocytes at retrieval (group I: low b-FSH quartile 8.4±3.7 versus high b-FSH quartile 6.4±2.7, P < 0.02; group II: 7.5±4.0 versus 6.3±3.0, P < 0.047), whereas no difference with regard to oocyte yield was observed in patients above age 35 (group III: low b-FSH quartile 5.5±3.1 versus high b-FSH quartile 5.6±3.5). No statistical correlation was found between FSH quartiles and clinical pregnancy rates or miscarriage. CONCLUSIONS: In young women, age-specific high b-FSH levels, even within normal ranges, are associated with significantly reduced numbers of oocytes retrieved. B-FSH concentrations should, therefore, be interpreted in an age-specific manner to allow for appropriate patient counselling in IVF. [ABSTRACT FROM AUTHOR]

We demonstrate Floquet engineering in a basic yet scalable 2D architecture of individually trapped and controlled ions. Local parametric modulations of detuned trapping potentials steer the strength of long-range interion couplings and the related Peierls phase of the motional state. In our proof of principle, we initialize large coherent states and tune modulation parameters to control trajectories, directions, and interferences of the phonon flow. Our findings open a new pathway for future Floquet-based trapped-ion quantum simulators targeting correlated topological phenomena and dynamical gauge fields. [ABSTRACT FROM AUTHOR]

Quantum theory predicts intriguing dynamics during drastic changes of external conditions. We switch the trapping field of two ions sufficiently fast to tear apart quantum fluctuations, i.e., create pairs of phonons and, thereby, squeeze the ions' motional state. This process can be interpreted as an experimental analog to cosmological particle creation and is accompanied by the formation of spatial entanglement. Hence, our platform allows one to study the causal connections of squeezing, pair creation, and entanglement and might permit one to cross-fertilize between concepts in cosmology and applications of quantum information processing. [ABSTRACT FROM AUTHOR]

Trapped ions are a promising platform for envisioned quantum simulators, with outstanding results in one-dimensional ion crystals. However, theory requires not only interactions at long range, but also higher dimensionality. We operate a basic triangular array of three individually trapped ions based on scalable microfabrication technology. We demonstrate coherent coupling, tunable in real time and enabling interference in 2D, an essential building block for a reconfigurable quantum simulator. Mitigating motional heating will permit accessing the quantum regime and 2D experimental quantum simulations. [ABSTRACT FROM AUTHOR]

We study experimentally and theoretically discrete solitons in crystalline structures consisting of several tens of laser-cooled ions confined in a radio frequency trap. Resonantly exciting localized, spectrally gapped vibrational modes of the soliton, a nonlinear mechanism leads to a nonequilibrium steady state of the continuously cooled crystal. We find that the propagation and the escape of the soliton out of its quasi-one-dimensional channel can be described as a thermal activation mechanism. We control the effective temperature of the soliton's collective coordinate by the amplitude of the external excitation. Furthermore, the global trapping potential permits controlling the soliton dynamics and realizing directed transport depending on its topological charge. [ABSTRACT FROM AUTHOR]

We use trapped atomic ions forming a hybrid Coulomb crystal and exploit its phonons to study an isolated quantum system composed of a single spin coupled to an engineered bosonic environment. We increase the complexity of the system by adding ions and controlling coherent couplings and, thereby, we observe the emergence of thermalization: Time averages of spin observables approach microcanonical averages while related fluctuations decay. Our platform features precise control of system size, coupling strength, and isolation from the external world to explore the dynamics of equilibration and thermalization. [ABSTRACT FROM AUTHOR]