Time evolution of open quantum many-body systems

We establish a generic method to analyze the time evolution of open quantum many-body systems. Our approach is based on a variational integration of the quantum master equation describing the dynamics and naturally connects to a variational principle for its nonequilibrium steady state. We successfully apply our variational method to study dissipative Rydberg gases, finding excellent quantitative agreement with small-scale simulations of the full quantum master equation. We observe that correlations related to non-Markovian behavior play a significant role during the relaxation dynamics towards the steady state. We further quantify this non-Markovianity and find it to be closely connected to an information-theoretical measure of quantum and classical correlations.Comment: 5+3 pages, 8 figure

RIT Process and Device Simulation with Microtec

Microtec, a diffusion-drift model simulator by Siborg Systems, Inc., was used to simulate RIT’s process for a 2-micron NFET (Long Channel), a scaled down NFET (Short Channel), and our new advanced CMOS Process NFET. The accuracy of the simulator was tested with voltage threshold curves, sub-threshold characteristic tests, potential distribution plots, doping profiles, and oxide growth measurements. Microtec proved to be able to easily model RIT’s device performance and process characteristics with only a small amount of modification

Multicritical behavior in dissipative Ising models

We analyze theoretically the many-body dynamics of a dissipative Ising model in a transverse field using a variational approach. We find that the steady state phase diagram is substantially modified compared to its equilibrium counterpart, including the appearance of a multicritical point belonging to a different universality class. Building on our variational analysis, we establish a field-theoretical treatment corresponding to a dissipative variant of a Ginzburg-Landau theory, which allows us to compute the upper critical dimension of the system. Finally, we present a possible experimental realization of the dissipative Ising model using ultracold Rydberg gases.Comment: 8 pages, 4 figure

Long-term survival and interruption of HAART in HIV-related pulmonary hypertension

Reported here is a case of a patient with pulmonary arterial hypertension related to HIV (PAHRH) in which lipodystrophy necessitated interruption of highly active antiretroviral therapy (HAART) and long-term survival was the outcome. Although previous studies have suggested antiretroviral therapy may benefit patients with this rare complication of HIV infection, no worsening of PAHRH was observed when HAART was interrupted. Clinical and echocardiographic parameters remained stable during 7 months of follow up. In cases in which HAART is associated with relevant toxicity, interruption of HAART in patients with PAHRH can be considered, but should be used only if no alternatives are available. Close follow-up is warrante

Enhanced structural correlations accelerate diffusion in charge-stabilized colloidal suspensions

Theoretical calculations for colloidal charge-stabilized and hard sphere suspensions show that hydrodynamic interactions yield a qualitatively different particle concentration dependence of the short-time self-diffusion coefficient. The effect, however, is numerically small and hardly accessible by conventional light scattering experiments. Applying multiple-scattering decorrelation equipment and a careful data analysis we show that the theoretical prediction for charged particles is in agreement with our experimental results from aqueous polystyrene latex suspensions.Comment: 1 ps-file (MS-Word), 14 page

Variations of the McEliece Cryptosystem

Two variations of the McEliece cryptosystem are presented. The first one is based on a relaxation of the column permutation in the classical McEliece scrambling process. This is done in such a way that the Hamming weight of the error, added in the encryption process, can be controlled so that efficient decryption remains possible. The second variation is based on the use of spatially coupled moderate-density parity-check codes as secret codes. These codes are known for their excellent error-correction performance and allow for a relatively low key size in the cryptosystem. For both variants the security with respect to known attacks is discussed

Phase Behaviour of Amphiphilic Monolayers: Theory and Simulation

Coarse grained models of monolayers of amphiphiles (Langmuir monolayers) have been studied theoretically and by computer simulations. We discuss some of the insights obtained with this approach, and present new simulation results which show that idealised models can successfully reproduce essential aspects of the generic phase behaviour of Langmuir monolayers.Comment: To appear in J. Phys.: Cond. Matte

Selection bias in general practice research : analysis in a cohort of pregnant Danish women

Funding: The Novo Nordic Foundation (NNF130C0002689), Region Zealand (15-000342), The Danish Research Foundation for General Practice (EMN-2017-00265), A.P. Møller Foundation (21.15 12.2016.16-87), Lilly and Herbert Hansen Foundation (07.11.2016-006), and Jacob and Orla Madsen Foundation (11.05.2015. 5421) have financially supported the project. The funding sources were not involved in the research design, collection, analysis and interpretation of data, writing of the report and decision regarding submission for publication. The authors are responsible for the contents of this article.Peer reviewedPublisher PD

Alveolar Echinococcosis of the Liver in an Adult with Human Immunodeficiency Virus Type-1 Infection

Abstract. : We describe a patient with human immunodeficiency virus type-1 (HIV) infection and alveolar echinococcosis (AE) with a focus on two messages. Despite being severely immunocompromised over years the patient exhibited a long-term asymptomatic course of AE. This is in clear contrast to reports describing accelerated courses of AE in immunocompromised patients. The patient had therapeutic mebendazole drug levels with only 1/10 of the normal drug dose. He was co-treated with protease inhibitors for his HIV infection. These drugs are known as strong inhibitors of cytochrome P450 3A4 (CYP3A4)-dependent metabolism. We speculate that benzimidazoles and protease inhibitors interfere at the CYP3A4-level. The first report of co-infection of HIV and accelerated AE was in a young girl with an extremely low CD4 cell count and an abrogated lymphoproliferative responsiveness to parasite antigen stimulation. Since the CD4 cell count in our patient remained in the range of 27-150 cells/µl, we speculate that there was a critical threshold of immunosupression for constraining AE. Initial treatment with albendazole for AE added to the current highly active antiretroviral treatment (HAART), and suppressive toxoplasmosis therapy became complicated by pancytopenia. After full recovery of the bone marrow, mebendazole was introduced with a new HAART and the previously prescribed toxoplasmosis maintenance therapy. Surprisingly, efficient mebendazole levels were achieved with an uncommonly low dose. These observations suggest that the benzimidazoles, albendazole and mebendazole, may interact with protease inhibitors, which are known for their strong inhibition of the CYP3A