2,528 research outputs found
Experimental Realization of Optimal Noise Estimation for a General Pauli Channel
We present the experimental realization of the optimal estimation protocol
for a Pauli noisy channel. The method is based on the generation of 2-qubit
Bell states and the introduction of quantum noise in a controlled way on one of
the state subsystems. The efficiency of the optimal estimation, achieved by a
Bell measurement, is shown to outperform quantum process tomography
Consistent Truncation to Three Dimensional (Super-)gravity
For a general three dimensional theory of (super-)gravity coupled to
arbitrary matter fields with arbitrary set of higher derivative terms in the
effective action, we give an algorithm for consistently truncating the theory
to a theory of pure (super-)gravity with the gravitational sector containing
only Einstein-Hilbert, cosmological constant and Chern-Simons terms. We also
outline the procedure for finding the parameters of the truncated theory. As an
example we consider dimensional reduction on S^2 of the 5-dimensional minimal
supergravity with curvature squared terms and obtain the truncated theory
without any curvature squared terms. This truncated theory reproduces correctly
the exact central charge of the boundary CFT.Comment: LaTeX file, 22 page
Localizing limit cycles : from numeric to analytical results
Presentation given by participants of the joint international multidisciplinary workshop MURPHYS-HSFS-2016 (MUltiRate Processes and HYSteresis; Hysteresis and Slow-Fast Systems), which was dedicated to the mathematical theory and applications of multiple scale systems and systems with hysteresis, and held at the Centre de Recerca Matemà tica (CRM) in Barcelona from June 13th to 17th, 2016This note presents the results of [4]. It deals with the problem of location and existence of limit cycles for real planar polynomial differential systems. We provide a method to construct Poincaré-Bendixson regions by using transversal curves, that enables us to prove the existence of a limit cycle that has been numerically detected. We apply our results to several known systems, like the Brusselator one or some Liénard systems, to prove the existence of the limit cycles and to locate them very precisely in the phase space. Our method, combined with some other classical tools can be applied to obtain sharp bounds for the bifurcation values of a saddle-node bifurcation of limit cycles, as we do for the Rychkov syste
Relational superposition measurements with a material quantum ruler
In physics, it is crucial to identify operational measurement procedures to
give physical meaning to abstract quantities. There has been significant effort
to define time operationally using quantum systems, but the same has not been
achieved for space. Developing an operational procedure to obtain information
about the location of a quantum system is particularly important for a theory
combining general relativity and quantum theory, which cannot rest on the
classical notion of spacetime. Here, we take a first step towards this goal,
and introduce a model to describe an extended material quantum system working
as a position measurement device. Such a "quantum ruler" is composed of N
harmonically interacting dipoles and serves as a (quantum) reference system for
the position of another quantum system. We show that we can define a quantum
measurement procedure corresponding to the "superposition of positions", and
that by performing this measurement we can distinguish when the quantum system
is in a coherent or incoherent superposition in the position basis. The model
is fully relational, because the only meaningful variables are the relative
positions between the ruler and the system, and the measurement is expressed in
terms of an interaction between the measurement device and the measured system.Comment: 30 pages, 6 figure
Expanding Precompetitive Multisector Collaborations to Advance Drug Development and Pharmacogenomics.
On the number of limit cycles of the Lienard equation
In this paper, we study a Lienard system of the form dot{x}=y-F(x),
dot{y}=-x, where F(x) is an odd polynomial. We introduce a method that gives a
sequence of algebraic approximations to the equation of each limit cycle of the
system. This sequence seems to converge to the exact equation of each limit
cycle. We obtain also a sequence of polynomials R_n(x) whose roots of odd
multiplicity are related to the number and location of the limit cycles of the
system.Comment: 10 pages, 5 figures. Submitted to Physical Review
Time to redefine endometriosis including its pro-fibrotic nature
Endometriosis is currently defined as presence of endometrial epithelial and stromal cells at ectopic sites. This simple and straightforward definition has served us well since its original introduction. However, with advances in disease knowledge, endometrial stromal and glands have been shown to represent only a minor component of endometriotic lesions and they are often absent in some disease forms. In rectovaginal nodules, the glandular epithelium is often not surrounded by stroma and frequently no epithelium can be identified in the wall of ovarian endometriomas. On the other hand, a smooth muscle component and fibrosis represent consistent features of all disease forms. Based on these observations, we believe that the definition of endometriosis should be reconsidered and reworded as 'A fibrotic condition in which endometrial stroma and epithelium can be identified'. The main reasons for this change are: (1) to foster the evaluation of fibrosis in studies on endometriosis pathogenesis using animal models; (2) to limit potential false negative diagnoses if pathologists stick stringently to the current definition of endometriosis requiring the demonstration of endometrial stromal and glands; (3) to consider fibrosis as a potential target for treatment in endometriosis. This opinion article is aimed at boosting the attention paid to a largely neglected aspect of the disease. We hope that targeting the fibrotic process might increase success in developing new therapeutic approaches
Predicting the outcome of heart failure against chronic-ischemic heart disease in elderly population – Machine learning approach based on logistic regression, case to Villa Scassi hospital Genoa, Italy
Totally 167 patients were admitted at cardiology ward in Villa Scassi hospital, Genoa, Italy. We worked with two control groups: heart failure 59 patients (mean age: 71.37 ± 13.27 years) and chronic-ischemic heart disease 108 patients (mean age: 68.85 ± 11.3 years). Nine parameters: Hb, Serum Creatinine, LDL, HDL, Triglycerides, ALT, AST, hs-cTnI, CRP were evaluated onset to hospitalization. We aimed to identify significant independent predictors relative to the outcome of heart failure versus chronic-ischemic heart disease and select combination of biochemical parameters in logistic regression-based model that would provide on average excellent discrimination to the outcome of heart failure versus chronic-ischemic heart
disease in elderly population. Applying 20-fold repeated stratified cross-validation, 4:1 train/test ratio split, we have found that probability of heart failure, provides best discrimination of the outcome of heart failure against chronic-ischemic heart disease
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