Decoherence suppression by uncollapsing

We show that the qubit decoherence due to zero-temperature energy relaxation can be almost completely suppressed by using the quantum uncollapsing procedure. To protect a qubit state, a partial quantum measurement moves it towards the ground state, where it is kept during the storage period, while the second partial measurement restores the initial state. This procedure preferentially selects the cases without energy decay events. Stronger decoherence suppression requires smaller selection probability; a desired point in this trade-off can be chosen by varying the measurement strength. The experiment can be realized in a straightforward way using the superconducting phase qubit.Comment: 4 page

Simple quantum error detection and correction for superconducting qubits

We analyze simple quantum error detection and quantum error correction protocols relevant to current experiments with superconducting qubits. We show that for qubits with energy relaxation the repetitive N-qubit codes cannot be used for quantum error correction, but can be used for quantum error detection. In the latter case it is sufficient to use only two qubits for the encoding. In the analysis we demonstrate a useful technique of unraveling the qubit energy relaxation into "relaxation" and "no relaxation" scenarios. Also, we propose and numerically analyze several two-qubit algorithms for quantum error detection/correction, which can be readily realized at the present-day level of the phase qubit technology.Comment: 14 pages, 8 figure

Plant functional traits suggest novel ecological strategy for an invasive shrub in an understorey woody plant community

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86864/1/j.1365-2664.2011.02049.x.pd

Evidence for acquisition of virulence effectors in pathogenic chytrids

Background The decline in amphibian populations across the world is frequently linked to the infection of the chytrid fungus Batrachochytrium dendrobatidis (Bd). This is particularly perplexing because Bd was only recently discovered in 1999 and no chytrid fungus had previously been identified as a vertebrate pathogen. Results In this study, we show that two large families of known virulence effector genes, crinkler (CRN) proteins and serine peptidases, were acquired by Bd from oomycete pathogens and bacteria, respectively. These two families have been duplicated after their acquisition by Bd. Additional selection analyses indicate that both families evolved under strong positive selection, suggesting that they are involved in the adaptation of Bd to its hosts. Conclusions We propose that the acquisition of virulence effectors, in combination with habitat disruption and climate change, may have driven the Bd epidemics and the decline in amphibian populations. This finding provides a starting point for biochemical investigations of chytridiomycosis

A review of innovation strategies and processes to improve access to AT: Looking ahead to open innovation ecosystems.

It is essential to understand the strategies and processes which are deployed currently across the Assistive Technology (AT) space toward measuring innovation. The main aim of this paper is to identify functional innovation strategies and processes which are being or can be deployed in the AT space to increase access to AT globally. We conducted a scoping review of innovation strategies and processes in peer-reviewed literature databases and complemented this by identifying case studies demonstrating innovation strategies. The review includes WHO world region, publication year, AT type and a sector analysis against the Systems-Market for Assistive and Related Technologies Framework. We analyzed the case studies and interviews using thematic analysis. We included 91 papers out of 3,127 after review along with 72 case studies. Our results showed that product innovations were more prevalent than provision or supply innovations across papers and case studies. Case studies yielded two themes: open innovation (OI); radical and disruptive innovation. Financial instruments which encourage OI are needed and we recommend pursuing OI for AT innovation. Embedding AT within larger societal missions will be key to success governments and investors need to understand what AT is and their translational socioeconomic value

The Type 2 Diabetes Knowledge Portal: an Open access Genetic Resource Dedicated to Type 2 Diabetes and Related Traits

Associations between human genetic variation and clinical phenotypes have become a foundation of biomedical research. Most repositories of these data seek to be disease-agnostic and therefore lack disease-focused views. The Type 2 Diabetes Knowledge Portal (T2DKP) is a public resource of genetic datasets and genomic annotations dedicated to type 2 diabetes (T2D) and related traits. Here, we seek to make the T2DKP more accessible to prospective users and more useful to existing users. First, we evaluate the T2DKP\u27s comprehensiveness by comparing its datasets with those of other repositories. Second, we describe how researchers unfamiliar with human genetic data can begin using and correctly interpreting them via the T2DKP. Third, we describe how existing users can extend their current workflows to use the full suite of tools offered by the T2DKP. We finally discuss the lessons offered by the T2DKP toward the goal of democratizing access to complex disease genetic results

GA4GH: International policies and standards for data sharing across genomic research and healthcare.

The Global Alliance for Genomics and Health (GA4GH) aims to accelerate biomedical advances by enabling the responsible sharing of clinical and genomic data through both harmonized data aggregation and federated approaches. The decreasing cost of genomic sequencing (along with other genome-wide molecular assays) and increasing evidence of its clinical utility will soon drive the generation of sequence data from tens of millions of humans, with increasing levels of diversity. In this perspective, we present the GA4GH strategies for addressing the major challenges of this data revolution. We describe the GA4GH organization, which is fueled by the development efforts of eight Work Streams and informed by the needs of 24 Driver Projects and other key stakeholders. We present the GA4GH suite of secure, interoperable technical standards and policy frameworks and review the current status of standards, their relevance to key domains of research and clinical care, and future plans of GA4GH. Broad international participation in building, adopting, and deploying GA4GH standards and frameworks will catalyze an unprecedented effort in data sharing that will be critical to advancing genomic medicine and ensuring that all populations can access its benefits

Quantum State Protection and Transfer Using Superconducting Qubits

This dissertation presents a theoretical analysis of protocols relevant for quantum information processing with superconducting qubits. The purpose of these protocols is decoherence suppression and quantum information transfer. Our analysis makes use of the standard density matrix formalism and Kraus operator (operator-sum) representation of quantum operations. We also use the mathematical trick of unravelling continuous evolution into discrete scenarios with corresponding probabilities.We show that decoherence due to zero-temperature energy relaxation can be almost completely suppressed, probabilistically, by weak measurement reversal (also known as quantum uncollapsing). To protect a qubit, a weak (partial) quantum measurement moves it towards the ground state, where it is kept during the storage period, while the second partial measurement restores the initial state. This procedure preferentially selects the cases without energy decay events. Stronger decoherence suppression requires smaller selection probability; a desired point in this trade-off can be chosen by varying the measurement strength.We also analyze several simple quantum error correction (QEC) and quantum error detection (QED) protocols, relevant to superconducting qubits. We show that for energy relaxation the repetitive N-qubit quantum codes cannot be used for QEC, but can be used for QED (also known as probabilistic error correction). Moreover, the repetitive code with only two qubits is sufficient for QED. We also present several other two-qubit algorithms realizable with the current technology of superconducting phase qubits; these algorithms can demonstrate QEC for intentional errors and QED for real decoherence.We also analyze a procedure designed to transfer the state of a microwave qubit from one superconducting resonator to another resonator via a transmission line; the emission and capture of the microwave energy is achieved using tunable couplers. The procedure is shown to be robust against experimental imperfections of required pulse shapes. Our results also indicate that a successful state transfer requires nearly equal resonator frequencies for the entire duration of the procedure

Nanostructures and lithographic method for producing highly sensitive substrates for surface-enhanced spectroscopy

A method for producing planar extended electrodes with nanoscale spacings that exhibit very large SERS signals, with each nanoscale gap having one well-defined hot spot. The resulting highly sensitive substrate has extended metal electrodes separated by a nanoscale gap. The electrodes act as optical antennas to enhance dramatically the local electromagnetic field for purposes of spectroscopy or nonlinear optics. SERS response is consistent with a very small number of molecules in the hotspot, showing blinking and wandering of Raman lines. Sensitivity is sufficiently high that SERS from physisorbed atmospheric contaminants may be detected after minutes of exposure to ambient conditions