1,503 research outputs found
Quantum imaginary time evolution and quantum annealing meet topological sector optimization
Optimization problems are the core challenge in many fields of science and
engineering, yet general and effective methods are scarce for searching optimal
solutions. Quantum computing has been envisioned to help solve such problems,
for example, the quantum annealing (QA) method based on adiabatic evolution has
been extensively explored and successfully implemented on quantum simulators
such as D-wave's annealers and some Rydberg arrays. In this work, we
investigate topological sector optimization (TSO) problem, which attracts
particular interests in the quantum many-body physics community. We reveal that
the topology induced by frustration in the spin model is an intrinsic
obstruction for QA and other traditional methods to approach the ground state.
We demonstrate that the optimization difficulties of TSO problem are not
restricted to the gaplessness, but are also due to the topological nature which
are often ignored for the analysis of optimization problems before. To solve
TSO problems, we utilize quantum imaginary time evolution (QITE) with a
possible realization on quantum computers, which exploits the property of
quantum superposition to explore the full Hilbert space and can thus address
optimization problems of topological nature. We report the performance of
different quantum optimization algorithms on TSO problems and demonstrate that
their capability to address optimization problems are distinct even when
considering the quantum computational resources required for practical QITE
implementations
Aerosolized amphotericin B as prophylaxis for invasive pulmonary aspergillosis: a meta-analysis
SummaryObjectivesInvasive pulmonary aspergillosis (IPA) is associated with high mortality in high-risk (immunosuppressed) patients. Many studies have investigated whether prophylactic inhalation of amphotericin B (AMB) reduces the incidence of IPA, but no definitive conclusions have been reached. The present meta-analysis was performed to evaluate the efficacy of prophylactic inhalation of AMB for the prevention of IPA.MethodsMEDLINE and other databases were searched for relevant articles published until December 2013. Randomized controlled trials that compared aerosolized AMB with placebo were included. Two reviewers independently assessed and extracted the data of all trials.ResultsSix animal studies and two clinical trials involving 768 high-risk patients were eligible. The animal studies showed lower overall mortality rate among animals that underwent aerosolized AMB prophylaxis (odds ratio (OR) 0.13, 95% confidence interval (CI) 0.08–0.21). Similarly, the clinical trials showed a lower incidence of IPA among patients who underwent aerosolized AMB prophylaxis (OR 0.42, 95% CI 0.22–0.79).ConclusionsThis analysis provides evidence supporting the notion that the prophylactic use of aerosolized AMB effectively reduces the incidence of IPA among high-risk patients
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