Now showing items 11-30 of 125

• #### D-Wave pairing driven by bipolaric modes related to giant electron-phonon anomalies in high-Tc superconductors ﻿

(Journal of Statistical Mechanics: Theory and Experiment, 2015-12-31)
Taking into account microscopic properties of most usual high-Tc superconductors, like cuprates, we define a class of microscopic model Hamiltonians for two fermions (electrons or holes) and one boson (bipolaron) on the ...
• #### Darrieus-Landau instabilities in the framework of the G-equation ﻿

(Digital proceedings of the 8th European Combustion Meeting, 18-21 April 2017, Dubrovnik, Croatia, 2017-04)
We consider a model formulation of the flame front propagation in turbulent premixed combustion based on stochastic fluctuations imposed to the mean flame position. In particular, the mean flame motion is described by ...
• #### Decay of Complex-time Determinantal and Pfaffian\ Correlation Functionals in Lattices ﻿

(Commun. Math. Phys., 2018-01-24)
We supplement the determinantal and Pfaffian bounds of Sims and Warzel (Commun Math Phys 347:903--931, 2016) for many-body localization of quasi-free fermions, by considering the high dimensional case and complex-time ...
• #### Diagonalizing quadratic bosonic operators by non-autonomous flow equations volker bach ﻿

(Memoirs of the American Mathematical Society, 2016-01-01)
We study a non-autonomous, non-linear evolution equation on the space of operators on a complex Hilbert space. We specify assumptions that ensure the global existence of its solutions and allow us to derive its asymptotics ...
• #### The Discreteness-driven Relaxation of Collisionless Gravitating Systems: Entropy Evolution in External Potentials, N-dependence, and the Role of Chaos ﻿

(The Astrophysical Journal, 2019-01-10)
We investigate the old problem of the fast relaxation of collisionless N-body systems that are collapsing or perturbed, emphasizing the importance of (noncollisional) discreteness effects. We integrate orbit ensembles in ...
• #### Discretizations of the spectral fractional Laplacian on general domains with Dirichlet, Neumann, and Robin boundary conditions ﻿

(2017-04-28)
In this work, we propose novel discretisations of the spectral fractional Laplacian on bounded domains based on the integral formulation of the operator via the heat-semigroup formalism. Specifically, we combine suitable ...
• #### Effective self-similar expansion for the Gross-Pitaevskii equation ﻿

(Physical Review A, 2018-04)
We consider an effective scaling approach for the free expansion of a one-dimensional quantum wave packet, consisting in a self-similar evolution to be satisfied on average, i.e., by integrating over the coordinates. A ...
• #### Equilibrium and Transport Properties of Quantum Many-Body Systems ﻿

(2019-10-30)
This thesis is a study of equilibrium and dynamical properties of macroscopic quantum many-body problems. An important part of the manuscript concerns the study of heat and charge transport properties of fermions on the ...
• #### Equisingularity in One-Parameter Families of Generically Reduced Curves ﻿

(International Mathematics Research Notices, 2016-01-01)
We explore some equisingularity criteria in one-parameter families of generically reduced curves. We prove the equivalence between Whitney regularity and Zariski’s discriminant criterion. We prove that topological triviality ...
• #### Equivariant motivic integration and proof of the integral identity conjecture for regular functions ﻿

(Mathematische Annalen, 2019-12-02)
We develop Denef-Loeser’s motivic integration to an equivariant version and use it to prove the full integral identity conjecture for regular functions. In comparison with Hartmann’s work, the equivariant Grothendieck ...
• #### Euler reflexion formulas for motivic multiple zeta functions ﻿

(Journal of Algebraic Geometry, 2017-05-14)
We introduce a new notion of $\boxast$-product of two integrable series with coefficients in distinct Grothendieck rings of algebraic varieties, preserving the integrability of and commuting with the limit of rational ...
• #### Examples of varieties with index one on C1 fields ﻿

(Journal of Number Theory, 2019-04-16)
Let K be the fraction field of a Henselian discrete valuation ring with algebraically closed residue field k. In this article we give a sufficient criterion for a projective variety over such a field to have index 1.
• #### Existence of “$d$-wave” Pairs and Density Waves in a Class of Microscopic Models for High Transition Temperature Superconductors ﻿

(2018-03-21)
High-temperature superconductors have different properties than conventional superconductors, one of these important properties is non-isotropic symmetry of the order parameter. In this work we present a model that shows ...
• #### Finite-energy Lévy-type motion through heterogeneous ensemble of Brownian particles ﻿

(Journal of Physics A: Mathematical and Theoretical, 2019-02-01)
Complex systems are known to display anomalous diffusion, whose signature is a space/time scaling $x \sim t^\delta$ with $\delta \neq 1/2$ in the probability density function (PDF). Anomalous diffusion can emerge jointly ...
• #### Fire-spotting generated fires. Part I: The role of atmospheric stability ﻿

(Applied Mathematical Modelling, 2019-02)
This is the first part of two papers concerning fire-spotting generated fires. In this part we deal with the impact of macroscale factors, such as the atmospheric stability, and in the second part we deal with mesoscale ...
• #### Fractional Brownian motion in a finite interval: correlations effect depletion or accretion zones of particles near boundaries ﻿

(New Journal of Physics, 2019-02)
Fractional Brownian motion (FBM) is a Gaussian stochastic process with stationary, long-time correlated increments and is frequently used to model anomalous diffusion processes. We study numerically FBM confined to a finite ...
• #### Fractional kinetics emerging from ergodicity breaking in random media ﻿

(Physical Review E, 2016)
We present a modelling approach for diffusion in a complex medium characterized by a random lengthscale. The resulting stochastic process shows subdiffusion with a behavior in qualitative agreement with single particle ...
• #### Fractional kinetics in random/complex media ﻿

(Handbook of Fractional Calculus with Applications Volume 5 Applications in Physics, Part B, 2019)
In this chapter, we consider a randomly-scaled Gaussian process and discuss a number of applications to model fractional diffusion. Actually, this approach can be understood as a Gaussian diffusion in a medium characterized ...
• #### Fractional relaxation with time-varying coefficient ﻿

(Fractional Calculus and Applied Analysis, 2014-12-31)
From the point of view of the general theory of the hyper-Bessel operators, we consider a particular operator that is suitable to generalize the standard process of relaxation by taking into account both memory effects of ...
• #### From G - Equation to Michelson - Sivashinsky Equation in Turbulent Premixed Combustion Modelling ﻿

(Proceedings/Extended Abstract Book (6 pages) of the XXXIX Meeting of the Italian Section of the Combustion Institute, Naples, Italy, 2017-06-20)
It is well known that the Michelson-Sivashinky equation describes hydrodynamic instabilities in turbulent premixed combustion. Here a formulation of the flame front propagation based on the G-equation and on stochastic ...