A generalized multi-polaron expansion for the spin-boson model: Environmental entanglement and the biased two-state system

We develop a systematic variational coherent state expansion for the many-body ground state of the spin-boson model, in which a quantum two-level system is coupled to a continuum of harmonic oscillators. Energetic constraints at the heart of this technique are rationalized in terms of polarons (displacements of the bath states in agreement with classical expectations) and antipolarons (counter-displacements due to quantum tunneling effects). We present a comprehensive study of the ground state two-level system population and coherence as a function of tunneling amplitude, dissipation strength, and bias (akin to asymmetry of the double well potential defining the two-state system). The entanglement among the different environmental modes is investigated by looking at spectroscopic signatures of the bipartite entanglement entropy between a given environmental mode and all the other modes. We observe a drastic change in behavior of this entropy for increasing dissipation, indicative of the entangled nature of the environmental states. In addition, the entropy spreads over a large energy range at strong dissipation, a testimony to the wide entanglement window characterizing the underlying Kondo state. Finally, comparisons to accurate numerical renormalization group calculations and to the exact Bethe Ansatz solution of the model demonstrate the rapid convergence of our variationally-optimized multi-polaron expansion, suggesting that it should also be a useful tool for dissipative models of greater complexity, as relevant for numerous systems of interest in quantum physics and chemistry.Comment: 17 pages, 14 figure

Analisis Faktor Yang Mempengaruhi Kemandirian Pada Pasien Cedera Kepala Yang Pernah Dirawat Di Igd RSUD Dr. R. Koesma Tuban

Cedera kepala akibat kecelakaan lalulintas merupakan penyebab utama disabilitas dan mortalitas. Functional Independence Measure (FIM) merupakan salah satu pengukuran kemandirian pasien cedera kepala. Beberapa faktor yang dicurigai adalah usia, mekanisme cedera, skor awal GCS, hipotensi, diameter pupil dan reaksi cahaya, CT scan, konsumsi alkohol, dan lama perawatan. Tujuan penelitian ini adalah mengetahui faktor yang mempengaruhi kemandirian pasien cedera kepala. Penelitian ini bersifat analitik observasional dengan menggunakan rancangan retrospektif terhadap107 sampel rekam medis RSUD dr. R. Koesma Tuban dari periode Januari-April 2016. Teknik sampling yang digunakan adalah teknik cluster random sampling dengan kriteria inklusi dan ekslusi. Instrumen yang digunakan lembar checklist dan lembar FIM. Analisis menggunakan uji koefisien kontingensi dan regresi logistik. Hasil uji regresi logistik menunjukan faktor yang mempengaruhi adalah GCS (p=0,996) dan Pupil (p=0,077). Persamaan yang didapat y = 0,357 + 19,434 (GCS) + 2,041 (Pupil). Hasil uji Hosmer and Lameshow menunjukan kalibrasi yang baik (p=1,000), nilai AUC menunjukan bahwa 93,6% persamaan regresi yang diperoleh mampu membedakan kemandirian pasien cedera kepala berdasarkan variabel GCS dan pupil, sisanya yaitu 6,4% dipengaruhi oleh faktor lain. Skor GCS yangrendah pada awal cedera berhubungan dengan prognosa yang buruk, sedangkan abnormalitas fungsi pupil, gangguan gerakan ekstraokular, pola-pola respons motorik yang abnormal seperti postur fleksor dan postur ekstensor, juga memprediksikan outcome yang buruk setelah cedera kepala.Kesimpulan dari penelitian ini adalah Skor awal GCS dan Pupil menjadi faktor yang dominan berpengaruh terhadap kemandirian. Oleh karena itu, perawat perlu meningkatkan manajemen pasien cedera kepala pada fase emergency dengan tidak mengabaikan pengukuran GCS dan Pupil

Coherent and incoherent dynamics in excitonic energy transfer: correlated fluctuations and off-resonance effects

We study the nature of the energy transfer process within a pair of coupled two-level systems (donor and acceptor) subject to interactions with the surrounding environment. Going beyond a standard weak-coupling approach, we derive a master equation within the polaron representation that allows for investigation of both weak and strong system-bath couplings, as well as reliable interpolation between these two limits. With this theory, we are then able to explore both coherent and incoherent regimes of energy transfer within the donor-acceptor pair. We elucidate how the degree of correlation in the donor and acceptor fluctuations, the donor-acceptor energy mismatch, and the range of the environment frequency distribution impact upon the energy transfer dynamics. In the resonant case (no energy mismatch) we describe in detail how a crossover from coherent to incoherent transfer dynamics occurs with increasing temperature [A. Nazir, Phys. Rev. Lett. 103, 146404 (2009)], and we also explore how fluctuation correlations are able to protect coherence in the energy transfer process. We show that a strict crossover criterion is harder to define when off-resonance, though we find qualitatively similar population dynamics to the resonant case with increasing temperature, while the amplitude of coherent population oscillations also becomes suppressed with growing site energy mismatch.Comment: 14 pages, 7 figures, builds upon PRL 103, 146404 (2009) (arXiv:0906.0592). Comments welcome. V2 - Section IV shortened to improve presentation, references updated, new Imperial College affiliation added for A. Nazir. Published versio

Stabilizing Spin Coherence Through Environmental Entanglement in Strongly Dissipative Quantum Systems

The key feature of a quantum spin coupled to a harmonic bath---a model dissipative quantum system---is competition between oscillator potential energy and spin tunneling rate. We show that these opposing tendencies cause environmental entanglement through superpositions of adiabatic and antiadiabatic oscillator states, which then stabilizes the spin coherence against strong dissipation. This insight motivates a fast-converging variational coherent-state expansion for the many-body ground state of the spin-boson model, which we substantiate via numerical quantum tomography.Comment: 5 pages, 3 figures, supplementary file attached. This article supersedes arXiv:1301.743

Development of Hepatocellular Carcinoma after Achieving Sustained HCVVirologic Response and Regression of Cirrhosis

Hepatocellular carcinoma (HCC) is the fastest growing cause of cancer mortality. Interferon/ribavirin and direct acting antiviral (DAA) therapy have successfully treated HCV infection and may halt the progression of fibrosis. It is generally believed that HCC primarily occurs in the background of HCV- related cirrhosis; theoretically, achieving sustained viral response (SVR) could decrease the incidence of HCC by slowing down fibrosing process; hence preventing progression of cirrhosis. Here, we present a case of 64-year-old female who was successfully treated for HCV infection with interferon in 1994. Patient achieved sustained viral response (SVR) and has been in remission for 23 years. In June 2017, she presented with abdominal pain and CT scan revealed a liver mass which was subsequently biopsied and proved to be HCC. Patient was treated with partial hepatectomy and histologic examination of the resected liver mass revealed well-differentiated HCC; non-neoplastic liver demonstrated features of regression of cirrhosis/fibrosis with fibrous expansion of few portal tracts and scattered very fine curvilinear fibrous septa; no portal/lobular inflammation was present. The patient developed HCC 23 years after achieving SVR. Significant regression of cirrhosis/fibrosis in the non-neoplastic liver argues against the usual course of HCC development in cirrhotic/advanced fibrotic setting, and suggests the possibility of an alternative phenomenon, e.g., latency of HCV and/or oncologic potential of HCV at the genomic level. This rare event raises certain questions which have not been properly investigated in the course of HCC development, such as: 1) Relationship between regression of cirrhosis/fibrosis and developing HCC; 2) If absence and regression of cirrhosis/fibrosis carries the same value; 3) Necessity of updating the surveillance criteria in patient with SVR lacking cirrhosis; and 4) Oncologic potential of HCV acquired at the genomic level; these questions/issues are currently under investigation.https://scholarlycommons.henryford.com/merf2020caserpt/1084/thumbnail.jp

Systemic Sclerosis with Gastrointestinal manifestations: a unique presentation

Systemic sclerosis is a chronic autoimmune disease of unknown etiology. Disease course usually begins with Raynaud’s phenomenon followed by skin sclerosis and internal organ involvement. Diagnosis is made based on the clinical symptoms, presence of antibodies and endoscopy with biopsy. With this background, we present a case of a 60-year female who was followed by GI clinic for treatment resistant dyspepsia, bloating and nausea. Past medical history was significant for fibromyalgia, Raynaud’s disease and transient ischemic attack. For evaluation of dyspepsia, she underwent endoscopy with gastric and esophageal biopsies, which were superficial and showed only non-specific chronic inflammation. Further, 24 hour pH monitoring results were unhelpful in making a definitive diagnosis. Esophageal manometry showed a hypertensive lower esophageal sphincter for which she underwent Heller’s myotomy. Her symptoms, however, persisted and she was scheduled to undergo laparoscopy and open gastric wall biopsy. Stomach biopsy revealed gastric mucosa showing focal vascular ectasia. There was significantly increased fibrosis involving the muscularis mucosae and propria (Figure A), highlighted by trichrome stain (Figure B-D). Following biopsy results, Scl-70 Ab test was performed and it turned out to be positive (42, Nunits). Thus, supporting the diagnosis of systemic sclerosis. Full thickness gastrointestinal tract biopsies of systemic sclerosis cases are rarely seen in routine surgical pathology practice. This case is unique because of the complexity of clinical presentation requiring open gastric wall biopsy but demonstrates the value of pathologic evaluation for diagnosis of rare autoimmune disorders such as systemic sclerosis.https://scholarlycommons.henryford.com/merf2020caserpt/1013/thumbnail.jp

ANALISIS PELAKSANAAN ASESMEN PEMBELAJARAN FISIKA TEKNIK PADA PROGRAM STUDI PENDIDIKAN FAKULTAS TEKNIK UNM

ABSTRACT This study is a survey research which aims to determine the existing implementation of learning engineering physics. The research object is a lecturer in engineering physics at the Education Studies Program Faculty of Engineering State University of Makassar. Aspects assessed were the assessment and learning undertaken by lecturers. Based on the analysis obtained results, namely: (1) assessment in physics learning techniques have not provided sufficient information on which to base the decision making learning; (2) supporting the implementation of the components such as the preparation and analysis of assessment items, assessment criteria and rubrics not become a habit of the lecturer in preparing their lecture; (3) sharing criteria and student involvement in the process of assessment (self-assessment or peer assessment) has not become a habit lecturer, and (4) the implementation of the assessment has not been able to identify students misconceptions against learning materials so that the principle of fairness in the assessment is still not realized. Keyword: Learning outcomes, assessment, Engineering Physic

Toward an mHealth Intervention for Smoking Cessation

The prevalence of tobacco dependence in the United States (US) remains alarming. Invariably, smoke-related health problems are the leading preventable causes of death in the US. Research has shown that a culturally tailored cessation counseling program can help reduce smoking and other tobacco usage. In this paper, we present a mobile health (mHealth) solution that leverages the Short Message Service (SMS) or text messaging feature of mobile devices to motivate behavior change among tobacco users. Our approach implements the Theory of Planned Behavior (TPB) and a phase-based framework. We make contributions to improving previous mHealth intervention approaches by delivering personalized and evidence-based motivational SMS messages to participants. Our proposed solution implements machine learning algorithms that take the participant\u27s demographic profile and previous smoking behavior into account. We discuss our preliminary evaluation of the system against a couple of pseudo-scenarios and our observation of the system\u27s performance

Building a Tailored Text Messaging System for Smoking Cessation in Native American Populations

When starting new and healthy habits or encouraging vigilance against returning to poor habits, a simple text message can be beneficial. Text messages also have the advantage of being easily accessible for lower-income populations spread over a rural area, who may not be able to afford smartphones with apps or data plans. Users benefit the most from text messages that are customized for them, but personalization requires time and effort on part of the user and the counselor. However, personalization that focuses on the cultural background of a pool of recipients, in addition to general personal preferences, can be a low-cost method of ensuring the best experience for patients interested in taking up new habits. In this paper, we discuss the development of a system for motivating users to quit smoking designed for Native American users in South Dakota, using text messaging as a daily intervention method for patients. Our results show that focusing on modular message customization options and messages with a conversational tone best helps our goal of providing users with customization options that help motivate them to live happy and healthy lifestyles

Home energy monitoring system towards smart control of energy consumption

The need to manage, control and reduce energy consumption has led researchers to propose reliable solutions based on new technologies to achieve this goal. Our contribution in this subject is presented in this paper and consists of the design, implementation and testing of a home energy monitoring system. The presented system is dedicated for residential customers and allows the monitoring and control of the energy consumption, based on distributed and central processing. The system includes distributed monitoring devices, a gateway and a graphical user interface (GUI). To connect the all parts we use a hybrid wireless solution based on the Wi-Fi and Bluetooth Low Energy standards. We present the design and the implementation of the monitoring device hardware as well as the embedded software used to calculate the electrical quantities. We also present the calibration methodology used to eliminate gain and offset errors. In terms of performance test results, we have achieved voltage measurement accuracy below 0.2% and current measurement accuracy below 0.5%. A GUI was also developed for the user to visualize and control remotely the household appliances.This work is supported by FCT with the reference project UID/EEA/04436/2013, COMPETE 2020 with the code POCI-01-0145-FEDER-006941