Erratum: Coalescence of Two Impurities in a Trapped One-Dimensional Bose Gas [Phys. Rev. Lett. 121, 080405 (2018)].

This corrects the article DOI: 10.1103/PhysRevLett.121.080405.

Realization of efficient quantum gates with a superconducting qubit-qutrit circuit.

Building a quantum computer is a daunting challenge since it requires good control but also good isolation from the environment to minimize decoherence. It is therefore important to realize quantum gates efficiently, using as few operations as possible, to reduce the amount of required control and operation time and thus improve the quantum state coherence. Here we propose a superconducting circuit for implementing a tunable system consisting of a qutrit coupled to two qubits. This system can efficiently accomplish various quantum information tasks, including generation of entanglement of the two qubits and conditional three-qubit quantum gates, such as the Toffoli and Fredkin gates. Furthermore, the system realizes a conditional geometric gate which may be used for holonomic (non-adiabatic) quantum computing. The efficiency, robustness and universality of the presented circuit makes it a promising candidate to serve as a building block for larger networks capable of performing involved quantum computational tasks.

Coalescence of Two Impurities in a Trapped One-dimensional Bose Gas.

We study the ground state of a one-dimensional (1D) trapped Bose gas with two mobile impurity particles. To investigate this setup, we develop a variational procedure in which the coordinates of the impurity particles are slowlike variables. We validate our method using the exact results obtained for small systems. Then, we discuss energies and pair densities for systems that contain of the order of 100 atoms. We show that bosonic noninteracting impurities cluster. To explain this clustering, we calculate and discuss induced impurity-impurity potentials in a harmonic trap. Further, we compute the force between static impurities in a ring (in the manner of the Casimir force), and contrast the two effective potentials: the one obtained from the mean-field approximation, and the one due to the one-phonon exchange. Our formalism and findings are important for understanding (beyond the polaron model) the physics of modern 1D cold-atom systems with more than one impurity.

Emergence of Clusters: Halos, Efimov States, and Experimental Signals.

We investigate the emergence of halos and Efimov states in nuclei by use of a newly designed model that combines self-consistent mean-field and three-body descriptions. Recent interest in neutron heavy calcium isotopes makes ^{72}Ca (^{70}Ca+n+n) an ideal realistic candidate on the neutron dripline, and we use it as a representative example that illustrates our broadly applicable conclusions. By smooth variation of the interactions we simulate the crossover from well-bound systems to structures beyond the threshold of binding, and find that halo configurations emerge from the mean-field structure for three-body binding energy less than ∼100 keV. Strong evidence is provided that Efimov states cannot exist in nuclei. The structure that bears the most resemblance to an Efimov state is a giant halo extending beyond the neutron-core scattering length. We show that the observable large-distance decay properties of the wave function can differ substantially from the bulk part at short distances, and that this evolution can be traced with our combination of few- and many-body formalisms. This connection is vital for interpretation of measurements such as those where an initial state is populated in a reaction or by a beta decay.

Quantum spin transistor with a Heisenberg spin chain.

Spin chains are paradigmatic systems for the studies of quantum phases and phase transitions, and for quantum information applications, including quantum computation and short-distance quantum communication. Here we propose and analyse a scheme for conditional state transfer in a Heisenberg XXZ spin chain which realizes a quantum spin transistor. In our scheme, the absence or presence of a control spin excitation in the central gate part of the spin chain results in either perfect transfer of an arbitrary state of a target spin between the weakly coupled input and output ports, or its complete blockade at the input port. We also discuss a possible proof-of-concept realization of the corresponding spin chain with a one-dimensional ensemble of cold atoms with strong contact interactions. Our scheme is generally applicable to various implementations of tunable spin chains, and it paves the way for the realization of integrated quantum logic elements.

Universal Three-Body Physics in Ultracold KRb Mixtures.

Ultracold atomic gases have recently become a driving force in few-body physics due to the observation of the Efimov effect. While initially observed in equal mass systems, one expects even richer few-body physics in the heteronuclear case. In previous experiments with ultracold mixtures of potassium and rubidium, an unexpected nonuniversal behavior of Efimov resonances was observed. In contrast, we measure the scattering length dependent three-body recombination coefficient in ultracold heteronuclear mixtures of ^{39}K-^{87}Rb and ^{41}K-^{87}Rb and do not observe any signatures of Efimov resonances for accessible scattering lengths in either mixture. Our results show good agreement with our theoretical model for the scattering dependent three-body recombination coefficient and reestablish universality across isotopic mixtures.

An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems.

Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique.

Strongly interacting confined quantum systems in one dimension.

In one dimension, the study of magnetism dates back to the dawn of quantum mechanics when Bethe solved the famous Heisenberg model that describes quantum behaviour in magnetic systems. In the last decade, one-dimensional (1D) systems have become a forefront area of research driven by the realization of the Tonks-Girardeau gas using cold atomic gases. Here we prove that 1D fermionic and bosonic systems with strong short-range interactions are solvable in arbitrary confining geometries by introducing a new energy-functional technique and obtaining the full spectrum of energies and eigenstates. As a first application, we calculate spatial correlations and show how both ferro- and antiferromagnetic states are present already for small system sizes that are prepared and studied in current experiments. Our work demonstrates the enormous potential for quantum manipulation of magnetic correlations at the microscopic scale.

Virial expansion coefficients in the harmonic approximation.

The virial expansion method is applied within a harmonic approximation to an interacting N-body system of identical fermions. We compute the canonical partition functions for two and three particles to get the two lowest orders in the expansion. The energy spectrum is carefully interpolated to reproduce ground-state properties at low temperature and the noninteracting high-temperature limit of constant virial coefficients. This resembles the smearing of shell effects in finite systems with increasing temperature. Numerical results are discussed for the second and third virial coefficients as functions of dimension, temperature, interaction, and transition temperature between low- and high-energy limits.

Quantum statistics and thermodynamics in the harmonic approximation.

We describe a method to compute thermodynamic quantities in the harmonic approximation for identical bosons and fermions in an external confining field. We use the canonical partition function where only energies and their degeneracies enter. The number of states of given energy and symmetry is found by separating the center-of-mass motion, and by counting the remaining states of given symmetry and excitation energy of the relative motion. The oscillator frequencies that enter the harmonic Hamiltonian can be derived from realistic model parameters, and the method corresponds to an effective interaction approach based on harmonic interactions. To demonstrate the method, we apply it to systems in two dimensions. Numerical calculations are compared to a brute force method, which is considerably more computationally intensive.

Few-body bound states in dipolar gases and their detection.

We consider dipolar interactions between heteronuclear molecules in a low-dimensional setup consisting of two one-dimensional tubes. We demonstrate that attraction between molecules in different tubes can overcome intratube repulsion and complexes with several molecules in the same tube are stable. In situ detection schemes of the few-body complexes are proposed. We discuss extensions to many tubes and layers, and outline the implications on many-body physics.

Model independence in two dimensions and polarized cold dipolar molecules.

We calculate the energy and wave functions of two particles confined to two spatial dimensions interacting via arbitrary anisotropic potentials with negative or zero net volume. The general rigorous analytic expressions are given in the weak coupling limit where universality or model independence are approached. The monopole part of anisotropic potentials is crucial in the universal limit. We illustrate the universality with a system of two arbitrarily polarized cold dipolar molecules in a bilayer. We discuss the transition to universality as a function of polarization and binding energy and compare analytic and numerical results obtained by the stochastic variational method. The universal limit is essentially reached for experimentally accessible strengths.

π phases in balanced fermionic superfluids on spin-dependent optical lattices.

We study a balanced two-component system of ultracold fermions in one dimension with attractive interactions and subject to a spin-dependent optical lattice potential of opposite sign for the two components. We find states with different types of modulated pairing order parameters which are conceptually similar to π phases discussed for superconductor-ferromagnet heterostructures. Increasing the lattice depth induces sharp transitions between states of different parity. While the origin of the order parameter oscillations is similar to the Fulde-Ferrel-Larkin-Ovchinnikov phase for paired states with spin imbalance, the current system is intrinsically stable to phase separation. We discuss experimental requirements for creating and probing these novel phases.

Trospium chloride once-daily extended release is effective and well tolerated for the treatment of overactive bladder syndrome: an integrated analysis of two randomised, phase III trials.

BACKGROUND: Trospium chloride is an antimuscarinic agent with a hydrophilic polar quaternary amine structure that is minimally metabolised by hepatic cytochrome P450 and is actively excreted in the urine, each of which confers a potential benefit with regard to efficacy and tolerability. PURPOSE: We analysed pooled data from two identically designed phase III trials of a once-daily, extended-release (XR) formulation of trospium chloride (trospium XR 60-mg capsules) in subjects with overactive bladder syndrome (OAB). METHODS: Adults with OAB of > or = 6 months' duration with urinary urgency, frequency and > or = 1 urge urinary incontinence (UUI) episode/day were enrolled in these multicentre, parallel-group, double-blind trials. Participants were randomised (1 : 1) to receive trospium XR 60 mg or placebo for 12 weeks. Primary efficacy variables were changes in urinary frequency and the number of UUI episodes/day. Adverse events (AEs) were recorded throughout. RESULTS: In total, 1165 subjects were randomised (trospium XR, 578; placebo, 587). At baseline, subjects averaged 12.8 toilet voids/day and 4.1 UUI episodes/day. Compared with placebo, subjects treated with trospium XR had significantly greater reductions from baseline in the mean number of toilet voids/day (-1.9 vs. -2.7; p < 0.001) and UUI episodes/day (-1.8 vs. -2.4; p < 0.001) at week 12. The most frequent AEs considered possibly related to study treatment were dry mouth (trospium XR, 10.7%; placebo, 3.7%) and constipation (trospium XR, 8.5%; placebo, 1.5%). Notably, rates of central nervous system (CNS) AEs were lower with trospium XR vs. placebo (dizziness: 0.2% vs. 1.0%; headache: 1.4% vs. 2.4%). CONCLUSIONS: Treatment with trospium XR resulted in statistically significant improvements in both of the dual primary and all of the secondary outcome variables. Trospium XR demonstrated favourable rates of AEs, particularly CNS AEs (numerically lower than with placebo) and dry mouth (lower than previously reported with trospium immediate-release, although not compared in a head-to-head study).

Darifenacin treatment for overactive bladder in patients who expressed dissatisfaction with prior extended-release antimuscarinic therapy.

INTRODUCTION AND OBJECTIVE: Patient perception of overactive bladder (OAB) treatment outcomes can be a useful indicator of benefit and may help drive persistence on treatment, which is known to be poor in OAB. It remains unclear whether OAB patients dissatisfied with one antimuscarinic can achieve satisfaction with another and supporting data are limited. This study investigated patient-reported outcomes and clinical parameters during darifenacin treatment in OAB patients who expressed dissatisfaction with prior extended-release (ER) oxybutynin or tolterodine therapy (administered for >or= 1 week within the past year). METHODS: This open-label study was conducted in darifenacin-naïve OAB patients. Patients received 7.5 mg darifenacin once daily with the possibility of up-titrating to 15 mg after 2 weeks, for up to 12 weeks. Efficacy parameters included the Patient's Perception of Bladder Condition (PPBC), patient satisfaction with treatment, micturition frequency and number of urgency and urge urinary incontinence (UUI) episodes. Adverse events (AEs) were also recorded. RESULTS: In total, 497 patients were treated (84.1% women). Darifenacin treatment resulted in statistically significant improvements in PPBC scores, micturition frequency, urgency and UUI episodes from baseline at 12 weeks. The improvements were similar for patients previously treated with oxybutynin ER or tolterodine ER. More than 85% of patients expressed satisfaction with darifenacin. As noted in other studies, the most common AEs were dry mouth and constipation, but these infrequently resulted in treatment discontinuation, which was low overall. CONCLUSIONS: In this study, PPBC score and OAB symptoms were significantly improved, and satisfaction was high during treatment with darifenacin (7.5/15 mg) in patients who were dissatisfied with the previous antimuscarinic treatment.

Effects of oxybutynin transdermal system on health-related quality of life and safety in men with overactive bladder and prostate conditions.

AIMS: Overactive bladder (OAB) is common in men and may exist concomitantly with benign prostatic hyperplasia (BPH) and obstruction. We present a subanalysis of results from men with OAB in a 6-month, open-label study of treatment with the oxybutynin transdermal system (OXY-TDS). Broad entry criteria were incorporated to yield a clinically representative population. METHODS: All participants received OXY-TDS 3.9 mg/day. Effectiveness was assessed by changes in scores on validated questionnaires, which included the single-item Patient Perception of Bladder Condition (PPBC), the King's Health Questionnaire (KHQ) and the Beck Depression Inventory-II (BDI-II). RESULTS: The proportion of men (n=369; mean age=69.6 years) who reported that their bladder condition caused moderate, severe or many severe problems (PPBC>or=4) improved from 77.3% at baseline to 38.1-53.6% in subsequent months. Mean KHQ scores decreased significantly (p12 (associated with a diagnosis of depression) decreased from 23.9% to 17.9% (p=0.0055). Men with a history of 'prostate problems' or use of 'BPH medication' (32.2%) had KHQ domain changes that were similar (p>or=0.1016) to those of other men. Most men (76.2%) reported no treatment-related adverse events; two men (0.5%) experienced symptoms of mild urinary retention, but neither required catheterisation. CONCLUSIONS: Oxybutynin transdermal system treatment of men with OAB was effective and well tolerated, regardless of history of prostate condition.

Neutrino-induced nucleosynthesis of A>64 nuclei: the nu p process.

We present a new nucleosynthesis process that we denote as the nu p process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A>64, , making this process a possible candidate to explain the origin of the solar abundances of (92,94)Mo and (96,98)Ru. This process also offers a natural explanation for the large abundance of Sr seen in a hyper-metal-poor star.

Efficacy, tolerability and safety of darifenacin, an M(3) selective receptor antagonist: an investigation of warning time in patients with OAB.

This double-blind, randomised placebo-controlled, multicentre study evaluated the efficacy, tolerability and safety of 12 weeks' treatment with controlled release darifenacin 15 mg once daily (qd), in 445 patients with overactive bladder (OAB). The primary endpoint was warning time (time from first sensation of urgency to voiding), and secondary endpoints included urge incontinence episodes and volume voided. Darifenacin treatment resulted in numerical increases in warning time, but these were not significant compared with placebo -- highlighting difficulties in assessing this parameter. Significant improvements were seen with darifenacin vs. placebo in urge incontinence episodes/week, volume voided and quality of life (QoL). Darifenacin was associated with increases in urgency-free time (UFT; time between any void to the next urgency event) vs. placebo. Treatment was well tolerated; the most commonly reported adverse events were the typical antimuscarinic effects of dry mouth and constipation, both infrequently leading to discontinuation. This study demonstrated the difficulty in measuring warning time, due in part to its subjective nature; the authors believe further investigation is warranted to allow urgency to be better defined. Further investigation of UFT is required to determine its role in evaluating urgency. The study confirmed that darifenacin 15 mg qd is an effective and well-tolerated treatment for OAB, which improves QoL.