Time-Linear Quantum Transport Simulations with Correlated Nonequilibrium Green's Functions.

We present a time-linear scaling method to simulate open and correlated quantum systems out of equilibrium. The method inherits from many-body perturbation theory the possibility to choose selectively the most relevant scattering processes in the dynamics, thereby paving the way to the real-time characterization of correlated ultrafast phenomena in quantum transport. The open system dynamics is described in terms of an "embedding correlator" from which the time-dependent current can be calculated using the Meir-Wingreen formula. We show how to efficiently implement our approach through a simple grafting into recently proposed time-linear Green's function methods for closed systems. Electron-electron and electron-phonon interactions can be treated on equal footing while preserving all fundamental conservation laws.

Real-Time GW: Toward an Ab Initio Description of the Ultrafast Carrier and Exciton Dynamics in Two-Dimensional Materials.

We demonstrate the feasibility of the time-linear scaling formulation of the GW method [Phys. Rev. Lett. 124, 076601 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.076601] for ab initio simulations of optically driven two-dimensional materials. The time-dependent GW equations are derived and solved numerically in the basis of Bloch states. We address carrier multiplication and relaxation in photoexcited graphene and find deviations from the typical exponential behavior predicted by the Markovian Boltzmann approach. For a resonantly pumped semiconductor we discover a self-sustained screening cascade leading to the Mott transition of coherent excitons. Our results draw attention to the importance of non-Markovian and dynamical screening effects in out-of-equilibrium phenomena.

Floquet Topological Phase of Nondriven p-Wave Nonequilibrium Excitonic Insulators.

The nontrivial topology of p-wave superfluids makes these systems attractive candidates in information technology. In this work we report on the topological state of a p-wave nonequilibrium excitonic insulator (NEQ-EI) and show how to steer a nontopological band insulator with bright p excitons toward this state by a suitable laser pulse, thus achieving a dynamical topological phase transition. The underlying mechanism behind the transition is the broken gauge-symmetry of the NEQ-EI which causes self-sustained persistent oscillations of the excitonic condensate and hence a Floquet topological state for high enough exciton densities. We show the formation of Floquet Majorana modes at the boundaries of the open system and discuss unique topological spectral signatures for time-resolved ARPES experiments. We emphasize that the topological properties of a p-wave NEQ-EI arise exclusively from the electron-hole Coulomb interaction as the system is not driven by external fields.

Ultrafast Quantum Interference in the Charge Migration of Tryptophan.

Extreme-ultraviolet-induced charge migration in biorelevant molecules is a fundamental step in the complex path leading to photodamage. In this work we propose a simple interpretation of the charge migration recently observed in an attosecond pump-probe experiment on the amino acid tryptophan. We find that the decay of the prominent low-frequency spectral structure with increasing pump-probe delay is due to a quantum beating between two geometrically distinct, almost degenerate charge oscillations. Quantum beating is ubiquitous in these systems, and at least on the few-to-tens of femtosecond time scales, it may dominate over decoherence the line intensities of time-resolved spectra. We also address the experimentally observed phase shift in the charge oscillations of two different amino acids, tryptophan and phenylalanine. Our results indicate that a beyond mean-field treatment of the electron dynamics is necessary to reproduce the correct behavior.

First-Principles Nonequilibrium Green's Function Approach to Ultrafast Charge Migration in Glycine.

We investigate the photoinduced ultrafast charge migration phenomenon in the glycine molecule using a recently proposed nonequilibrium Green's functions (NEGF) approach. We first consider the dynamics resulting from the sudden removal of an electron in the valence shells, finding a satisfactory agreement with available data. Then we explicitly simulate the laser-induced photoionization process and study the evolution of the system after the pulse. We disentangle polarization and correlation effects in the electron dynamics and assign the main frequencies to specific elements of the reduced one-particle density matrix. We show that electronic correlations renormalize the bare frequencies, redistribute the spectral weights, and give rise to new spectral features.

CHEERS: a tool for correlated hole-electron evolution from real-time simulations.

We put forward a practical nonequilibrium Green's function (NEGF) scheme to perform real-time evolutions of many-body interacting systems driven out of equilibrium by external fields. CHEERS is a computational tool to solve the NEGF equation of motion in the so called generalized Kadanoff-Baym ansatz and it can be used for model systems as well as first-principles Hamiltonians. Dynamical correlation (or memory) effects are added to the Hartree-Fock dynamics through a many-body self-energy. Applications to time-dependent quantum transport, time-resolved photoabsorption and other ultrafast phenomena are discussed.

Ultrafast Charge Migration in XUV Photoexcited Phenylalanine: A First-Principles Study Based on Real-Time Nonequilibrium Green's Functions.

The early-stage density oscillations of the electronic charge in molecules irradiated by an attosecond XUV pulse takes place on femto- or subfemtosecond time scales. This ultrafast charge migration process is a central topic in attoscience because it dictates the relaxation pathways of the molecular structure. A predictive quantum theory of ultrafast charge migration should incorporate the atomistic details of the molecule, electronic correlations, and the multitude of ionization channels activated by the broad-bandwidth XUV pulse. We propose a first-principles nonequilibrium Green's function method fulfilling all three requirements and apply it to a recent experiment on the photoexcited phenylalanine amino acid. Our results show that dynamical correlations are necessary for a quantitative overall agreement with the experimental data. In particular, we are able to capture the transient oscillations at frequencies 0.15 and 0.30 PHz in the hole density of the amine group as well as their suppression and the concomitant development of a new oscillation at frequency 0.25 PHz after ∼14 fs.

Dynamical formation and manipulation of Majorana fermions in driven quantum wires in contact with a superconductor.

Controlling the dynamics of Majorana fermions (MF) subject to time-varying driving fields is of fundamental importance for the practical realization of topological quantum computing. In this work we study how it is possible to dynamically generate and maintain the topological phase in cold-atom nanowires after the temporal variation of the Hamiltonian parameters. Remarkably we show that for a sudden quench the system can never relax toward a state exhibiting fully developed MF, independently of the initial and final Hamiltonians. Only for sufficiently slow protocols the system behaves adiabatically, and the topological phase can be reached. Finally we address the crucial question of how "adiabatic" a protocol must be in order to manipulate the MF inside the topological phase without deteriorating their Majorana character.

Insight on hole-hole interaction and magnetic order from dichroic auger-photoelectron coincidence spectra.

The absence of sharp structures in the Auger line shapes of partially filled bands has severely limited the use of electron spectroscopy in magnetic crystals and other correlated materials. By a novel interplay of experimental and theoretical techniques we achieve a combined understanding of the photoelectron, Auger, and Auger-photoelectron coincidence spectra (APECS) of the antiferromagnetic CoO. A recently discovered dichroic effect in angle resolved (DEAR) APECS reveals a complex pattern in the Auger line shape, which is here explained in detail, labeling the final states by their total spin. Since the dichroic effect exists in the antiferromagnetic state but vanishes at the Néel temperature, the DEAR-APECS technique detects the phase transition from its local effects, thus providing a unique tool to observe and understand magnetic correlations where the usual methods are not applicable.

Correlation-induced memory effects in transport properties of low-dimensional systems.

We demonstrate the remnant presence of initial correlations in the steady-state electrical current jS flowing between low-dimensional interacting leads. The leads are described as Luttinger liquids and electrons can tunnel via a quantum point contact. We derive an analytic result for the time-dependent current and show that ground-state correlations have a large impact on the relaxation and long-time behavior. In particular, the I-V characteristic is not reproduced by quenching the interaction in time. We further present a universal formula of jS for an arbitrary sequence of interaction quenches and it is established that jS is history dependent for nonsmooth switching process.

Unconventional quasiparticle lifetime in graphene.

We address the question of how large can the lifetime of electronic states be at low energies in graphene, below the scale of the optical phonon modes. For this purpose, we study the many-body effects at the K point of the spectrum, which induce a strong coupling between electron-hole pairs and out-of-plane phonons. We show the existence of a soft branch of hybrid states below the electron-hole continuum when graphene is close to the charge neutrality point, leading to an inverse lifetime proportional to the cube of the quasiparticle energy. This implies that a crossover should be observed in transport properties, from such a slow decay rate to the lower bound given at very low energies by the decay into acoustic phonons.

The fibrinolytic system components are increased in systemic sclerosis and modulated by Alprostadil (alpha1 ciclodestryn).

OBJECTIVES: To evaluate urokinase plasminogen activator (u-PA), urokinase plasminogen activator soluble receptor (su-PAR), plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA) plasma levels in SSc patients (pts) versus healthy controls and their modulation by intravenous alphacyclodestrine (Alprostadil). METHODS: Plasma levels of u-PA, su-PAR, PAI-1 and t-PA were measured in 40 SSc (34 lSSc and 6 dSSc) pts and in 30 healthy controls. In SSc, blood was drawn before and after 3 consecutive daily of Alprostadil infusion (60 mg in 250 cc NaCl 0.9%). RESULTS: In SSc su-PAR basal levels were higher than controls (7.48 +/- 2.5 vs 4.69 +/- 0.4 ng/ml; p = 0.001) and were significantly reduced by Alprostadil (5.93 +/- 1.7; p = 0.002), but remain higher than controls (p = 0.03). u-PA basal levels were higher than controls (3.78 +/- 1.5 vs 1.29 +/- 0.3 ng/ml; p < 0.001) and were reduced by Alprostadil (2.39 +/- 1.7; p < 0.001) to control levels. SSc PAI-1 basal levels were lower than controls (31.60 +/- 7.7 vs 48.30 +/- 6.8 ng/ml; p < 0.001) and increased by Alprostadil (34.66 +/- 5.4; p = 0.04), but lower than controls (p < 0.001). SSc t-PA basal levels were higher in respect to controls (1645.81 +/- 792.7 vs 571.95 +/- 75.5 pg/ml; p < 0.0001) and reduced by Alprostadil (1318.06 +/- 603.5; p = 0.04), but still higher than controls (p = 0.001). CONCLUSION: Fibrinolysis were increased in SSc. Infusions of Alprostadil modulate u-PA, su-PAR, PAI-1 and t-PA, restoring near normal levels. In SSc, fibrinolysis system may become a potential target for new therapies.

Selection of clinical, patient-reported, and economic end points in acute exacerbation of chronic bronchitis.

BACKGROUND: Acute exacerbation of chronic bronchitis (AECB) places tremendous burden on patients, providers, employers, and health care systems. OBJECTIVE: The purpose of this paper is to (1) review the clinical, patient-reported, and economic measures used to evaluate disease burden and treatment effectiveness in AECB in clinical trials and (2) propose a guide for selecting study end points in AECB that will help capture all the relevant disease outcomes. METHODS: Two literature searches of the PubMed database were conducted to identify studies of clinical trials in bronchitis and evaluate the clinical, patient-reported, and economic end points used in these studies. RESULTS: Previous studies have focused primarily on clinician-assessed outcomes, which do not capture the full impact of AECB on patients' lives. Reporting mechanisms for most end points have been inconsistent, limiting the ability to compare information or interpret differences. Previous studies have given limited attention to patient-reported outcomes and the economic implications of AECB. Patient-reported outcomes such as speed of symptom relief and work productivity are important parameters for assessing treatment effectiveness and provide practical information for treatment evaluation. CONCLUSIONS: Additional research is needed to develop, examine, and validate patient-reported outcomes and the indirect costs of AECB. Measuring the relevant clinical, economic, and patient-reported outcomes in AECB patients using standardized methods may lead to a clearer understanding of the disease burden and the role, effectiveness, and cost-effectiveness of antibiotic treatment.

Workplace costs associated with acute exacerbation of chronic bronchitis: a comparison of moxifloxacin and levofloxacin.

Past research on acute exacerbation of chronic bronchitis (AECB) has not quantified related work loss. This exploratory study used data from a comparative trial of moxifloxacin versus levofloxacin to examine and compare workplace-related indirect costs. Both groups reported considerable absenteeism and lowered work productivity. However, patients taking moxifloxacin reported significantly higher work productivity than those taking levofloxacin (70% vs. 50%; P = .03). This translated into substantial indirect cost savings with moxifloxacin of $726/patient/year. Antibiotic choice in AECB can affect worker productivity and workplace-related indirect costs. Both insurers and employers should consider workplace-related indirect costs in addition to direct medical expenses when making formulary selections.

An economic evaluation of the JNC hypertension guidelines using data from a randomized controlled trial. Joint National Committee.

BACKGROUND: We wanted to determine the clinical cost of managing hypertension when following the Joint National Committee on Hypertension (JNC) guidelines, including drug therapy, the cost of monitoring for and treating side effects, compliance, and the cost of switching after therapeutic failures. METHODS: The base-case analysis considers antihypertensive agents from four therapeutic classes that were recently evaluated in a large randomized trial: enalapril, amlodipine, acebutolol, and chlorthalidone. Clinical evaluation, therapy, and monitoring for hypertension are modeled with an incidence-based Markov model. Clinical inputs include agent efficacy, side effects, and compliance with dosing schedules. JNC-recommended clinical and laboratory monitoring schedules are followed for each agent. Switches between classes occur for therapeutic failures. Drug and medical care costs are valued in 1995 US dollars. RESULTS: Although patients whose hypertension was initially treated with amlodipine achieved control more readily than patients who were given the other agents, the initial costs to achieve and maintain hypertension control were lowest for chlorthalidone ($641), followed by acebutolol ($920), amlodipine ($946), and enalapril ($948). Maintenance costs were lowest for chlorthalidone. For all agents except chlorthalidone, drug costs were the largest component of overall costs, followed by the costs of office visits, laboratory monitoring, and switching between classes for therapeutic failures. CONCLUSIONS: By following JNC guidelines, a slightly higher percentage of patients will achieve hypertension control with a newer class calcium channel blocker (amlodipine) but at a substantially higher cost than with a generic diuretic (chlorthalidone).

Agency for Health Care Policy and Research clinical practice guidelines.

OBJECTIVE: To review and summarize past activities of guidelines development at the Agency for Health Care Policy and Research (AHCPR) to enhance understanding of its new role and facilitate the development of new guidelines. DATA SYNTHESIS: The current Congressional climate and past criticisms of the guidelines development process have caused the AHCPR to reevaluate the way it produces guidelines. This assessment has resulted in the AHCPR restructuring its role to serve now as a science partner with private and public organizations. CONCLUSIONS: The development and role of evidence-based clinical practice guidelines are discussed, and the new roles of the AHCPR are described.

What are outcomes?

Understanding the important aspects of measuring outcomes will prepare pharmacists for changes in the marketplace and help them to assess the results of studies that will appear in subsequent issues of the Journal of the American Pharmaceutical Association and the research journals of other health services professions. In any evaluation of quality, all three quality measures (structure, process, and outcomes) must be considered. No one measure, in isolation, can describe the quality of care provided. Thus, the best patient care will come from health care practitioners who document structure, process, and outcomes and who evaluate these measures to provide appropriate care. The pharmacist cannot dispense prescriptions or provide pharmaceutical care without a pharmacy, drug inventory, or patient profiles, all of which are important structural inputs. The pharmacist takes a medication history, monitors the drug regimen, and counsels the patient on the appropriate way to use the treatment, all vital process activities. The objective of these inputs and actions is to improve the health status of the patient. Outcomes, therefore, are the intended endpoints of care, and occasional unintended effects (e.g., adverse drug reactions) as well. The future of pharmacy rests on demonstrating the positive effect of pharmaceutical care on patient outcomes. Pharmacists have always been part of the system of checks and balances in health care delivery. As the provision of health services changes, opportunities to assess the process and structure of care and to document patient outcomes will increase. Pharmacists are well positioned to intervene in patient care, but if they do not demonstrate the value of pharmacy services, they will face competition from alternative providers. Some have even suggested less expensive alternatives to having pharmacists dispense medications. Pharmacists must establish that their role goes beyond dispensing to include cognitive services such as compliance programs, screening services, glucose monitoring, and disease management programs. Pharmacists must document their role and its effects on patient outcomes.

Pharmacoepidemiology of bleeding events after use of r-alteplase or streptokinase in acute myocardial infarction.

OBJECTIVE: To determine in nonresearch, general medical practice conditions the comparative incidence and types of bleeding complications after the use of streptokinase (SK) and r-alteplase (recombinant tissue plasminogen activator, rt-PA) to treat acute myocardial infarction (AMI). DESIGN: Retrospective medical record review of concurrently treated patients (96-hour observation posttreatment) in 32 participating hospitals in the US. MAIN OUTCOME MEASURES: The medical record description of all bleeding events regarding the body site affected, changes in hemoglobin concentrations, blood products administered, and clinical outcome (permanent sequelae or death). Bleeding severity was determined by defined criteria. CONTROL DATA: Comorbidity and concomitant medications (e.g., aspirin, heparin, warfarin) likely to predispose or contribute to bleeding events were analyzed. DATA ANALYSIS: Logistic regression analysis. RESULTS: Data from 419 patients who received rt-PA and 207 who received SK were evaluated. In the 96-hour period after initiation of thrombolytic therapy, 30.5 and 31.9 percent of rt-PA and SK patients, respectively, experienced one or more bleeding events (crude risk ratio [CRR] = 1.04; 95 percent confidence interval [CI] 0.91-1.14; p = 0.73). In the first 24-hour period, 21.5 percent of rt-PA and 15.9 percent of SK patients experienced bleeding events (CRR = 0.74; 95 percent CI 0.42-1.15; p = 0.08). The leading types of bleeding and percents of all patients affected were: perivascular access site (18.4 percent), gastrointestinal (6.4 percent), skin/soft tissue/muscle (5.0 percent), urinary (3.4 percent), pulmonary (2.2 percent), systemic (1.9 percent), and oral (1.4 percent). Intracranial bleeding occurred in 4 rt-PA and 2 SK patients; 4 of these patients died. Events deemed clinically significant occurred in 15 rt-PA and 9 SK patients (3.8 percent of all patients). Ten patients likely died from these events, 6 within the first 24 hours. Three rt-PA patients and 1 who received SK (0.6 percent) died of cerebrovascular events within the first 24 hours. After controlling for demographic factors and therapeutic variables, using logistic regression analyses, no thrombolytic-related differences were found in the incidence or severity of bleeding following use of the two thrombolytics. CONCLUSIONS: These clinical data do not support a theoretical advantage of rt-PA to cause less bleeding propensity than SK.