Spectroscopic shifts as a signature of many-body localization phase transition in a one-dimensional transmon array

Abstract. Many-body localization is a phase of matter, which can occur in systems with strong disorder and interactions. One of the main characteristics of the many-body localized phase is that it cannot thermalize because localization slows or stops the propagation of information inside the system. Here, we study many-body localization in a one-dimensional transmon qubit array theoretically and numerically. Differing from frequently used approaches to many-body localization, we study the dynamical phase transition between a thermalized phase and the many-body localized phase by using a numerical method that is based on Fermi’s golden rule. This method makes it possible to distinguish the thermalized phase from the many-body localized phase and allows one to estimate how much disorder is required for the many-body localization phase transition. The distinction between the phases is made by a “soft” gap which appears at the zero-frequency and is known as a universal sign of localization. Unlike many other methods, which are used to recognize the many-body localized phase, the method in question can be easily applied to experiments. In the system that we have chosen the transmon qubits are capacitively coupled to each other, and the system is driven by a harmonic external magnetic flux that induces transitions between the energy eigenstates of the system. We calculated the numerical results for a system with eight transmon qubits, and to make calculations simpler, we assumed that the temperature of the system is infinite. The size of the system is limited by the computational expensiveness of our method. Somewhat surprisingly, the most laborious part of the calculations proved to be the Fermi’s golden rule, which is used to calculate the transition rate spectrum. The results show that the method in question can distinguish the many-body localized phase if the strength of disorder in the system is large, but near the many-body localized phase transition, it is challenging to observe the difference between the thermalized phase and the many-body localized phase. We calculated the transition rate spectra using different values of on-site interaction strength. The results show us that the disorder strength needed for the phase transition is smaller if the on-site interaction strength is weak or very strong. Lastly, we demonstrated the many-body localization phase transition by calculating the energy eigenstates as a function of disorder strength and observing how strongly the eigenenergies repel each other. This method proved to be relatively imprecise to specify the critical disorder strength needed for the many-body localized phase. However, one can clearly notice that the repulsion between energy levels grows weaker as the disorder strength grows stronger

Bohl-Perron type stability theorems for linear difference equations with infinite delay

Relation between two properties of linear difference equations with infinite delay is investigated: (i) exponential stability, (ii) \l^p-input \l^q-state stability (sometimes is called Perron's property). The latter means that solutions of the non-homogeneous equation with zero initial data belong to \l^q when non-homogeneous terms are in \l^p. It is assumed that at each moment the prehistory (the sequence of preceding states) belongs to some weighted \l^r-space with an exponentially fading weight (the phase space). Our main result states that (i) $\Leftrightarrow$ (ii) whenever $(p,q) \neq (1,\infty)$ and a certain boundedness condition on coefficients is fulfilled. This condition is sharp and ensures that, to some extent, exponential and \l^p-input \l^q-state stabilities does not depend on the choice of a phase space and parameters $p$ and $q$, respectively. \l^1-input \l^\infty-state stability corresponds to uniform stability. We provide some evidence that similar criteria should not be expected for non-fading memory spaces.Comment: To be published in Journal of Difference Equations and Application

Multimode physics of the unimon circuit

We consider a superconducting half-wavelength resonator that is grounded at its both ends and contains a single Josephson junction. Previously this circuit was considered as a unimon qubit in the single-mode approximation where dc-phase-biasing the junction to $\pi$ leads to increased anharmonicity and 99.9% experimentally observed single-qubit gate fidelity. Inspired by the promising first experimental results, we develop here a theoretical and numerical model for the detailed understanding of the multimode physics of the unimon circuit. To this end, first, we consider the high-frequency modes of the unimon circuit and find that even though these modes are at their ground state, they imply a significant renormalization to the Josephson energy. We introduce an efficient method how the relevant modes can be fully taken into account and show that unexcited high-lying modes lead to corrections in the qubit energy and anharmonicity. Interestingly, provided that the junction is offset from the middle of the circuit, we find strong cross-Kerr coupling strengths between a few low-lying modes. This observation paves the way for the utilization of the multimode structure, for example, as several qubits embedded into a single unimon circuit

Instalarea complicaţiilor renale la pacienţii cu ciroze hepatice: aspecte fiziopatologice

Conferinţa naţională în medicina internă din Republica Moldova cu participare internaţională, 19-20 mai 2011, Chişinău, Republica MoldovaSummary. Vasoconstrictive effect of Endotelin-1 (ET- 1), the role of Prostaglandin E-2 (PGE-2) in regulation of renal blood flow were evaluated at 82 patients with liver cirrhosis. The results show the vasoconstrictive effect of ET-1 with it significantly increased level and the inhibited levels of PGE-2 in decompensated cirrhosis, that produce negative effects on renal blood flow.Actualitate. Perfuzia renală compromisă determină sensibilitatea rinichiului la modificările hemodinamice şi la intervenţia toxinelor, manifestându- se prin modificarea activităţii agenţilor vasoconstrictori şi vasodilatatori la nivelul circulaţiei renale. Elucidarea modificărilor de eliberare endogenă a prostaglandinelor renale şi contribuţia ET-1 la instalarea tulburărilor hemodinamicii renale la pacienţii cu ciroză hepatică necesită studii suplimentare. Scopul lucrării: estimarea valorilor serice ale PGE-2 şi ET-1 la pacienţii cu ciroză hepatică, cu scopul de a elabora scheme moderne de prevenire şi tratament medicamentos al perturbărilor funcţionale renale în ciroza hepatică. Materiale şi metode. Au fost luaţi în studiu 82 de pacienţi cu ciroză hepatică clasele Child-Pugh A, B, C (vârsta medie de 51,5±1,56 ani), inclusiv 12 pacienţi diagnosticaţi cu SHR. ET-1 şi PGE-2 în ser au fost determinate prin metoda imunoenzimatică ELISA. Rezultate. S-a constatat că valorile PGE-2, comparativ cu grupul de control, scad odată cu avansarea cirozei hepatice, când perfuzia renală este compromisă, efectul vasodilatator al PGE-2 se micşorează semnificativ. Scăderea ratei de filtraţie glomerulară se asociază cu creşterea valorii ET-1, cu hiponatriemia, scăderea răspunsului la diuretice şi instalarea edemelor refractare la tratament diuretic. Concluzii. Sinteza PGE-2 în rinichi este inhibată de perturbările hemodinamice renale odată cu avansarea cirozei hepatice, ceea ce se manifestă prin micşorarea valorilor PGE-2 în ser. Se constată creşterea valorilor ET-1 ca cel mai marcat vasoconstrictor cunoscut la pacienţii cu ciroză hepatică clasa Child–Pugh C. Scăderea ratei de filtrare glomerulară se asociază cu creşterea valorii ET-1, hiponatriemie, prezenţa edemelor refractare la pacienţii cu ascită marcată

Оценка патогенетических факторов, влияющих на почечные осложнения у больных циррозом печени

Catedra de Medicină Internă nr. 5, USMF „Nicolae Testemiţanu”, Conferinţa Ştiinţifico-Practică „Medicina modernă, actualităţi şi perspective”, consacrată aniversării de 40 de ani ai Spitalului Clinic al Ministerului Sănătăţii, 27-28 mai, 2010, Chişinău, Republica MoldovaThe study involved 82 patients - 40 women and 42 men. Early detection of renal function impairment is a major predictive importance in managing patients with liver cirrhosis. In liver cirrhosis Child-Pugh class C, the renal hemodynamics is already compromised and is characterized by growth of vasoconstrictor factors. Azotemia in acute renal failure in hepato-renal syndrome does not reach very high values and is not associated with severe hyperpotassemia. PGE2 synthesis in the kidney is progressively inhibited by renal hemodynamic disturbances with advancing liver cirrhosis, which translates into decreasing PGE-1 levels in the serum. E1 is the vasoconstrictor with the most increased levels in patients with liver cirrhosis Child-Pugh class C and particularly in patients with hepato-renal syndrome. The decreased glomerular filtration rate is associated with an increased amount of ET-1, low sodium in the blood and edema in patients with refractory ascites. В исследовании включены 82 больных - 40 женщин и 42 мужчины. Раннее обнаружение почечной недостаточности является одним из основных прогностических факторов в менеджменте больных циррозом печени. При циррозе печени класса C по ChildPugh почечная гемодинамика уже скомпрометирована и характеризуется ростом сосудосуживающих факторов при отсутствии роста показателей эндогенных креатинина и мочевины в сыворотке крови. Азотемия в острой почечной недостаточности при печеночнопочечном синдроме не достигает больших значений и не связана с выраженной гиперкалиемией. Синтез PGE2 в почках постепенно замедляется из-за нарушения почечной гемодинамики при прогрессировании цирроза печени. У больных циррозом печени класса С по Child-Pugh, особенно при наличии печеночно-почечного синдрома, выявляется повышенная концентрация сосудосуживающего фактора Е1. Снижение скорости клубочковой фильтрации ассоциируется с повышенным содержанием ЕТ-1, низким содержанием натрия крови и с отеками

Intelligent Air Pollution Sensors Calibration for Extreme Events and Drifts Monitoring

Air quality low-cost sensors are affordable and can be deployed in massive scale in order to enable high-resolution spatio-temporal air pollution information. However, they often suffer from sensing accuracy, in particular when they are used for capturing extreme events. We propose an intelligent sensors calibration method that facilitates correcting low-cost sensors' measurements accurately and detecting the calibrators' drift. The proposed calibration method uses Bayesian framework to establish white-box and black-box calibrators. We evaluate the method in a controlled experiment under different types of smoking events. The calibration results show that the method accurately estimates the aerosol mass concentration during the smoking events. We show that black-box calibrators are more accurate than white-box calibrators. However, black-box calibrators may drift easily when a new smoking event occurs, while white-box calibrators remain robust. Therefore, we implement both of the calibrators in parallel to extract both calibrators' strengths and also enable drifting monitoring for calibration models. We also discuss that our method is implementable for other types of low-cost sensors suffered from sensing accuracy.Peer reviewe

Chlamydophila pneumoniae induces expression of Toll-like Receptor 4 and release of TNF-α and MIP-2 via an NF-κB pathway in rat type II pneumocytes

BACKGROUND: The role of alveolar type II cells in the regulation of innate and adaptive immunity is unclear. Toll-like receptors (TLRs) have been implicated in host defense. The purpose of the present study was to investigate whether Chlamydophila pneumoniae (I) alters the expression of TLR2 and/orTLR4 in type II cells in a (II) Rho-GTPase- and (III) NF-κB-dependent pathway, subsequently (IV) leading to the production of (IV) pro-inflammatory TNF-α and MIP-2. METHODS: Isolated rat type II pneumocytes were incubated with C. pneumoniae after pre-treatment with calcium chelator BAPTA-AM, inhibitors of NF-κB (parthenolide, SN50) or with a specific inhibitor of the Rho-GTPase (mevastatin). TLR2 and TLR4 mRNA expressions were analyzed by PCR. Activation of TLR4, Rac1, RhoA protein and NF-κB was determined by Western blotting and confocal laser scan microscopy (CLSM) and TNF-α and MIP-2 release by ELISA. RESULTS: Type II cells constitutively expressed TLR4 and TLR2 mRNA. A prominent induction of TLR4 but not TLR2 mRNA was detected after 2 hours of incubation with C. pneumoniae. The TLR4 protein expression reached a peak at 30 min, began to decrease within 1–2 hours and peaked again at 3 hours. Incubation of cells with heat-inactivated bacteria (56°C for 30 min) significantly reduced the TLR4 expression. Treated bacteria with polymyxin B (2 μg/ml) did not alter TLR4 expression. C. pneumoniae-induced NF-κB activity was blocked by TLR4 blocking antibodies. TLR4 mRNA and protein expression were inhibited in the presence of BAPTA-AM, SN50 or parthenolide. TNF-α and MIP-2 release was increased in type II cells in response to C. pneumoniae, whereas BAPTA-AM, SN50 or parthenolide decreased the C. pneumoniae-induced TNF-α and MIP-2 release. Mevastatin inhibited C. pneumoniae-mediated Rac1, RhoA and TLR4 expression. CONCLUSION: The TLR4 protein expression in rat type II cells is likely to be mediated by a heat-sensitive C. pneumoniae protein that induces a fast Ca(2+)-mediated NF-κB activity, necessary for maintenance of TLR4 expression and TNF-α and MIP-2 release through possibly Rac and Rho protein-dependent mechanism. These results indicate that type II pneumocytes play an important role in the innate pulmonary immune system and in inflammatory response mechanism of the alveolus

Market segmentation strategies for complex automotive products

With the advent of 'big data', the purpose of this empirical study was to take the opportunity to rethink conventional market segmentation strategies. This is particularly relevant for the automotive industry which is going through a period of rapid change with advanced technologies such as electric powered and autonomous vehicles, creating increased concerns as to how this complexity is communicated effectively. A mixed methods approach was utilised to collect data from multiple sources, incorporating in-depth discussion groups, semi-structured interviews, an online survey, and data collection of communication processes through the attendance of new car product launches. The results suggest that marketing departments should rethink their data capture methods to collect more relevant consumer information, not the contemporary trend of needs, attitude, and motivation variables that are difficult to identify and collect, but basic information on their level of familiarity with products through previous experience and exposure. The basic dimensions identified are characterised by a consumer's expertise, involvement, and familiarity with a product. The findings are synthesised into a theoretical framework to define differing levels of product complexity, which would enable manufacturers to provide more closely defined market segmentation strategies when communicating new product information