41 research outputs found
Quasi-particle spectrum and entanglement generation after a quench in the quantum Potts spin chain
Recently, a non-trivial relation between the quasi-particle spectrum and
entanglement entropy production was discovered in non-integrable quenches in
the paramagnetic Ising quantum spin chain. Here we study the dynamics of
analogous quenches in the quantum Potts spin chain. Tuning the parameters of
the system, we observe a sudden increase in the entanglement production rate,
which is shown to be related to the appearance of new quasiparticle excitations
in the post-quench spectrum. Our results demonstrate the generality of the
effect and support its interpretation as the non-equilibrium version of the
well-known Gibbs paradox related to mixing entropy which appears in systems
with a non-trivial quasi-particle spectrum.Comment: 15 pages, pdflatex, 30 pdf figures. v2: reformatted, 22 pages, typos
correcte
Bloch oscillations and the lack of the decay of the false vacuum in a one-dimensional quantum spin chain
We consider the decay of the false vacuum, realised within a quantum quench
into an anti-confining regime of the Ising spin chain with a magnetic field
opposite to the initial magnetisation. Although the effective linear potential
between the domain walls is repulsive, the time evolution of correlations still
shows a suppression of the light cone and a reduction of vacuum decay. The
suppressed decay is a lattice effect, and can be assigned to emergent Bloch
oscillations.Comment: 12 pages, 6 figures, pdflatex file. v2: 14 pages, new material and
references added, improved discussion, main results and conclusions unchange
S.13.1 Safety and efficacy of rituximab in SSc: an analysis from the European Scleroderma Trial and Research Group
Objectives. Objective of this multicentre, observational study was to assess effects and safety of rituximab (RTX) using the European Scleroderma Trial and Research Group (EUSTAR) cohort. Methods. EUSTAR centres were asked to provide specific data about SSc patients treated with RTX. Primary endpoints were predefined for different disease manifestations and compared between baseline and follow-up. Normally distributed data, analysed by paired t-test, are shown as mean (s.d.), and non-parametric data, analysed by Wilcoxon matched paired signed-rank test, are shown as median and interquartile range. Results. Data on 72 SSc patients treated with RTX were captured from 27 EUSTAR centres (51 females/21 males, 52 diffuse/19 limited, age 51 (44-60) years, disease duration 6 (3-10) years, 47 anti-Scl-70 positive). The most frequent RTX application scheme was 1000 mg × 2 within 2 weeks (57/72 patients). Co-treatment with other immunosuppressive drugs was reported in 28 patients. The modified Rodnan skin score (mRSS) significantly decreased vs baseline at 7 (5-9) months follow-up (n = 47, 18.2 + 10.9 vs 14.5 + 9.9, P = 0.0002). This was true for both patients with later disease stages and also for patients with earlier, extended skin fibrosis (dSSc with mRSS >16 at baseline, n = 26; 26.5 + 6.8 vs 20.4 + 8.9, P < 0.0001, reduction by 29.9%). S-HAQ was unchanged, but the European SSc activity score improved after rituximab treatment [n = 10; 3.7 (2.6-6.4) vs 1.7 (0.9-2.5), P = 0.01]. RTX had no effects on lung fibrosis (FVC, DLCO, TLC, HRCT score) in n = 11 patients with evidence for SSc-ILD. In SSc-polyarthritis patients, the DAS-28 declined at 6 months follow-up without reaching statistical significance [n = 8; 4.8 (2.5-7.5) vs 3.7 (2.6-6.6); p = 0.3]. Of 8, 5patients were RF and/or anti-CCP antibody positive. Similar results were obtained for secondary outcome measures (tender and swollen joint count, VAS, CRP, ESR). Additional positive effects of RTX were seen on SSc-related myopathy (CK levels, 273 + 177 vs 184 + 139; n = 12, P = 0.03) and on digital ulcers [total number per patient 1 (1-3) vs 0 (0-1); n = 23; P = 0.0086]. During RTX treatment 14 patients had infections, 3 serum sickness, 2 allergic reactions and 1 lung fibrosis aggravation, 29 fatigue and 9 nausea. Four patients died, one possibly related to RTX treatment (pneumonia and cardiac failure 1.5 months after RTX infusion). Conclusion. This large EUSTAR cohort study points at positive effects of RTX in particular on skin fibrosis, and suggests randomized controlled trial in SSc patient
Global Challenges After a Global Challenge: Lessons Learned from the COVID-19 Pandemic
Coronavirus disease 2019 (COVID-19) has affected not only individual lives but also the world and global systems, both natural and human-made. Besides millions of deaths and environmental challenges, the rapid spread of the infection and its very high socioeconomic impact have affected healthcare, economic status and wealth, and mental health across the globe. To better appreciate the pandemic's influence, multidisciplinary and interdisciplinary approaches are needed. In this chapter, world-leading scientists from different backgrounds share collectively their views about the pandemic's footprint and discuss challenges that face the international community.Peer reviewe
Relaxation and entropy generation after quenching quantum spin chains
This work considers entropy generation and relaxation in quantum quenches in the Ising and 3-state Potts spin chains. In the absence of explicit symmetry breaking we find universal ratios involving R\ue9nyi entropy growth rates and magnetisation relaxation for small quenches. We also demonstrate that the magnetisation relaxation rate provides an observable signature for the "dynamical Gibbs effect" which is a recently discovered characteristic non-monotonous behaviour of entropy growth linked to changes in the quasi-particle spectrum
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The staircase model: massless flows and hydrodynamics
The staircase model (SM) is a simple generalization of the sinh-Gordon model, obtained by complexifying the coupling constant. This produces a new theory with many interesting features. Chief among them is the fact that scaling functions such as Zamolodchikov's c-function display 'roaming' behaviour, that is, they visit the vicinity of an infinite number of conformal fixed points, the unitary minimal models of conformal field theory. This rich structure also makes the model an interesting candidate for study using the generalized hydrodynamic approach to integrable quantum field theory (IQFT). By studying hydrodynamic quantities such as the effective velocities of quasiparticles we can develop a more physical picture of interaction in the theory, both at and away from equilibrium. Indeed, we find that in the SM the effective velocity displays monotonicity features not found in any other IQFT. These admit a natural interpretation when investigated in the context of the massless theories known as MAk(+) models, which provide an effective description of massless flows between consecutive unitary minimal models. Consequently, we find that the effective velocity in the SM can be reconstructed by a 'cut and paste' procedure involving the equivalent functions associated to the massless excitations of suitable MAk(+) models. We also investigate the average currents and densities of higher spin conserved quantities in the partitioning protocol
L’infezione da papilloma virus umano (HPV) nei pazienti con artrite reumatoide trattati con farmaci biologici
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’infezione da HPV, la più frequente infezione a trasmissione sessuale, è comune nella popolazione sia maschile sia femminile. Il virus è presente in molte varianti genotipiche (oltre un centinaio), con diversa patogenicità . Alcuni tipi di HPV possono causare lesioni benigne a carico degli epiteli squamosi, come verruche e condilomi, mentre altri hanno potenzialità oncogene e sono associati a tumori dell’apparato genitale. Il carcinoma della cervice uterina è il primo tumore umano riconosciuto dalla OMS come riconducibile totalmente ad un agente infettivo, con il DNA del virus HPV isolato nel 90-100% dei casi 1. Prima di raggiungere lo stadio di invasività , questo tumore a lenta evoluzione è preceduto da lesioni displastiche precancerose che possono essere identificate con Pap-test o altre metodiche (su cui si basano i programmi di screening). La maggior parte delle infezioni da HPV si risolve spontaneamente grazie alla risposta immunitaria di tipo cellulare. Nell’evoluzione tumorale, oltre alla presenza di genotipi ad alto rischio, pare assumano un ruolo importante fattori legati all’ospite, quali età , stato ormonale e familiarit