Improving quantum state detection with adaptive sequential observations

For many quantum systems intended for information processing, one detects the logical state of a qubit by integrating a continuously observed quantity over time. For example, ion and atom qubits are typically measured by driving a cycling transition and counting the number of photons observed from the resulting fluorescence. Instead of recording only the total observed count in a fixed time interval, one can observe the photon arrival times and get a state detection advantage by using the temporal structure in a model such as a Hidden Markov Model. We study what further advantage may be achieved by applying pulses to adaptively transform the state during the observation. We give a three-state example where adaptively chosen transformations yield a clear advantage, and we compare performances on an ion example, where we see improvements in some regimes. We provide a software package that can be used for exploration of temporally resolved strategies with and without adaptively chosen transformations.Comment: Submitted for publication in Quantum Science and Technology. 26 pages, 8 figures. Corrected typos in appendix, updated acknowledgement

An atomic boson sampler

A boson sampler implements a restricted model of quantum computing. It is defined by the ability to sample from the distribution resulting from the interference of identical bosons propagating according to programmable, non-interacting dynamics. Here, we demonstrate a new combination of tools for implementing boson sampling using ultracold atoms in a two-dimensional, tunnel-coupled optical lattice. These tools include fast and programmable preparation of large ensembles of nearly identical bosonic atoms ($99.5^{+0.5}_{-1.6}\;\%$ indistinguishability) by means of rearrangement with optical tweezers and high-fidelity optical cooling, propagation for variable evolution time in the lattice with low loss ($5.0(2)\;\%$, independent of evolution time), and high fidelity detection of the atom positions after their evolution (typically $99.8(1)\;\%$). With this system, we study specific instances of boson sampling involving up to $180$ atoms distributed among $\sim 1000$ sites in the lattice. Direct verification of a given boson sampling distribution is not feasible in this regime. Instead, we introduce and perform targeted tests to determine the indistinguishability of the prepared atoms, to characterize the applied family of single particle unitaries, and to observe expected bunching features due to interference for a large range of atom numbers. When extended to interacting systems, our work demonstrates the core capabilities required to directly assemble ground and excited states in simulations of various Hubbard models.Comment: 20 pages, 7 figures (main text and methods); 8 pages, 2 figures (supplemental materials

A phase 3, multi-center, multinational, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of levofloxacin inhalation solution (APT-1026) in stable cystic fibrosis patients

Rationale For patients with cystic fibrosis (CF), the use of inhaled antibiotics has become standard of care to suppress chronic Pseudomonas airways infection. There are limited antibiotic options formulated and approved for inhaled use and antibiotic efficacies attenuate over time, making additional inhaled antibiotic classes desirable. APT-1026 (levofloxacin inhalation solution, LIS) is a fluoroquinolone in development for management of chronic P. aeruginosa airways infection in patients with CF. Objectives To compare the safety and efficacy of a 28-day course of treatment with LIS 240 mg or placebo BID in persons ≥ 12 years old with CF and chronic P. aeruginosa infection. Methods A multinational, randomized (2:1), double-blinded study of LIS and placebo over 28 days in CF patients ≥ 12 years with chronic P. aeruginosa infection. Time to exacerbation was the primary endpoint. FEV1 (% predicted) and patient-reported quality of life were among secondary endpoints. Main results Baseline demographics for 330 subjects (LIS = 220) were similar although significantly more patients randomized to LIS had experienced multiple exacerbations in the year prior to study entry. There was no statistically significant difference in protocol-defined pulmonary exacerbations between treatment arms. Relative change in FEV1% predicted from baseline was significantly greater for patients randomized to LIS compared to those randomized to placebo (mean difference 1.31%, p = 0.01 [95% CI 0.27, 2.34%]). LIS was well-tolerated, with dysguesia the most frequent adverse event. Conclusions LIS did not demonstrate a difference in time to next exacerbation when compared to placebo. Reasons for this result are discussed but may be due to an imbalance in the frequency of prior pulmonary exacerbations between the two groups. An improvement in FEV1 (% predicted) at 28 days was observed and LIS was well tolerated. LIS is safe and has a potential role in the management of CF patients with chronic P. aeruginosa

High-fidelity indirect readout of trapped-ion hyperfine qubits

We propose and demonstrate a protocol for high-fidelity indirect readout of trapped ion hyperfine qubits, where the state of a $^9\text{Be}^+$ qubit ion is mapped to a $^{25}\text{Mg}^+$ readout ion using laser-driven Raman transitions. By partitioning the $^9\text{Be}^+$ ground state hyperfine manifold into two subspaces representing the two qubit states and choosing appropriate laser parameters, the protocol can be made robust to spontaneous photon scattering errors on the Raman transitions, enabling repetition for increased readout fidelity. We demonstrate combined readout and back-action errors for the two subspaces of $1.2^{+1.1}_{-0.6} \times 10^{-4}$ and $0^{+1.9}_{-0} \times 10^{-5}$ with 68% confidence while avoiding decoherence of spectator qubits due to stray resonant light that is inherent to direct fluorescence detection.Comment: 7 + 6 pages, 3 + 1 figure

A phase 3, open-label, randomized trial to evaluate the safety and efficacy of levofloxacin inhalation solution (APT-1026) versus tobramycin inhalation solution in stable cystic fibrosis patients

Background: Inhaled antibiotics are standard of care for persons with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa airway infection. APT-1026 (levofloxacin inhalation solution, LIS) is fluoroquinolone in development. We compared the safety and efficacy of LIS to tobramycin inhalation solution (TIS) in persons ≥12 years old with CF and chronic P. aeruginosa infection. Methods: This multinational, randomized (2:1), non-inferiority study compared LIS and TIS over three 28-day on/off cycles. Day 28 FEV1 % predicted change was the primary endpoint. Time to exacerbation and patient-reported quality of life superiority were among secondary endpoints. Results: Baseline demographics for 282 subjects were comparable. Non-inferiority was demonstrated (1.86% predicted mean FEV1 difference [95% CI −0.66 to 4.39%]). LIS was well-tolerated, with dysguesia (taste distortion) the most frequent adverse event. Conclusions: LIS is a safe and effective therapy for the management of CF patients with chronic P. aeruginosa

Prevalence and risk factors for mesh erosion after laparoscopic-assisted sacrocolpopexy

The purpose of this study is to identify risk factors for mesh erosion in women undergoing minimally invasive sacrocolpopexy (MISC). We hypothesize that erosion is higher in subjects undergoing concomitant hysterectomy. This is a retrospective cohort study of women who underwent MISC between November 2004 and January 2009. Demographics, operative techniques, and outcomes were abstracted from medical records. Multivariable regression identified odds of erosion. Of 188 MISC procedures 19(10%) had erosions. Erosion was higher in those with total vaginal hysterectomy (TVH) compared to both post-hysterectomy (23% vs. 5%, p = 0.003) and supracervical hysterectomy (SCH) (23% vs. 5%, p = 0.109) groups. In multivariable regression, the odds of erosion for TVH was 5.67 (95% CI: 1.88–17.10) compared to post-hysterectomy. Smoking, the use of collagen-coated mesh, transvaginal dissection, and mesh attachment transvaginally were no longer significant in the multivariable regression model. Based on this study, surgeons should consider supracervical hysterectomy over total vaginal hysterectomy as the procedure of choice in association with MISC unless removal of the cervix is otherwise indicated

The Local Role in Homeland Security

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73848/1/j.1540-5893.2005.00236.x.pd

Patterns and rates of exonic de novo mutations in autism spectrum disorders

Autism spectrum disorders (ASD) are believed to have genetic and environmental origins, yet in only a modest fraction of individuals can specific causes be identified1,2. To identify further genetic risk factors, we assess the role of de novo mutations in ASD by sequencing the exomes of ASD cases and their parents (n= 175 trios). Fewer than half of the cases (46.3%) carry a missense or nonsense de novo variant and the overall rate of mutation is only modestly higher than the expected rate. In contrast, there is significantly enriched connectivity among the proteins encoded by genes harboring de novo missense or nonsense mutations, and excess connectivity to prior ASD genes of major effect, suggesting a subset of observed events are relevant to ASD risk. The small increase in rate of de novo events, when taken together with the connections among the proteins themselves and to ASD, are consistent with an important but limited role for de novo point mutations, similar to that documented for de novo copy number variants. Genetic models incorporating these data suggest that the majority of observed de novo events are unconnected to ASD, those that do confer risk are distributed across many genes and are incompletely penetrant (i.e., not necessarily causal). Our results support polygenic models in which spontaneous coding mutations in any of a large number of genes increases risk by 5 to 20-fold. Despite the challenge posed by such models, results from de novo events and a large parallel case-control study provide strong evidence in favor of CHD8 and KATNAL2 as genuine autism risk factors