We consider the gravity-capillary water waves equations for a bi-dimensional fluid with a periodic one-dimensional free surface. We prove a rigorous reduction of this system to Birkhoff normal form up to cubic degree. Due to the possible presence of three-wave resonances for general values of gravity, surface tension, and depth, such normal form may be not trivial and exhibit a chaotic dynamics (Wilton ripples). Nevertheless, we prove that for all the values of gravity, surface tension, and depth, initial data that are of size $$ \varepsilon $$in a sufficiently smooth Sobolev space leads to a solution that remains in an $$ \varepsilon $$-ball of the same Sobolev space up times of order $$ \varepsilon ^{-2}$$. We exploit that the three-wave resonances are finitely many, and the Hamiltonian nature of the Birkhoff normal form.

VL - 3 SN - 2523-3688 UR - https://doi.org/10.1007/s42286-020-00036-8 IS - 1 JO - Water Waves ER - TY - JOUR T1 - Quantitative lower bounds to the Euclidean and the Gaussian Cheeger constants JF - Ann. Fenn. Math. Y1 - 2021 A1 - Julin, V. A1 - Saracco, G. VL - 46 ER - TY - ABST T1 - Quantum Systems at The Brink. Existence and Decay Rates of Bound States at Thresholds; Critical Potentials and dimensionality Y1 - 2021 A1 - Dirk Hundertmark A1 - Michal Jex A1 - Markus Lange JF - arXiv:2107.14128 ER - TY - JOUR T1 - Quasi-optimal mesh sequence construction through Smoothed Adaptive Finite Element Methods JF - SIAM Journal on Scientific Computing Y1 - 2021 A1 - Ornela Mulita A1 - Stefano Giani A1 - Luca Heltai ER - TY - JOUR T1 - Quasistatic Limit of a Dynamic Viscoelastic Model with Memory Y1 - 2021 A1 - Gianni Dal Maso A1 - Francesco Sapio AB -We study the behaviour of the solutions to a dynamic evolution problem for a viscoelastic model with long memory, when the rate of change of the data tends to zero. We prove that a suitably rescaled version of the solutions converges to the solution of the corresponding stationary problem.

SN - 1424-9294 UR - https://doi.org/10.1007/s00032-021-00343-w JO - Milan Journal of Mathematics ER - TY - ABST T1 - Quantum Systems at The Brink: Properties of Atomic Bound States at The Ionization Threshold Y1 - 2020 A1 - Dirk Hundertmark A1 - Michal Jex A1 - Markus Lange ER - TY - ABST T1 - Quantum Systems at The Brink. Existence and Decay Rates of Bound States at Thresholds; Atoms Y1 - 2019 A1 - Dirk Hundertmark A1 - Michal Jex A1 - Markus Lange JF - arXiv:1908.05016 ER - TY - ABST T1 - Quantum Systems at The Brink. Existence and Decay Rates of Bound States at Thresholds; Helium Y1 - 2019 A1 - Dirk Hundertmark A1 - Michal Jex A1 - Markus Lange JF - arXiv:1908.04883 ER - TY - RPRT T1 - Quasi-continuous vector fields on RCD spaces Y1 - 2019 A1 - Clément Debin A1 - Nicola Gigli A1 - Enrico Pasqualetto ER - TY - JOUR T1 - On the Quasistatic Limit of Dynamic Evolutions for a Peeling Test in Dimension One JF - Journal of Nonlinear Science Y1 - 2018 A1 - Giuliano Lazzaroni A1 - Lorenzo Nardini AB -The aim of this paper is to study the quasistatic limit of a one-dimensional model of dynamic debonding. We start from a dynamic problem that strongly couples the wave equation in a time-dependent domain with Griffith's criterion for the evolution of the domain. Passing to the limit as inertia tends to zero, we find that the limit evolution satisfies a stability condition; however, the activation rule in Griffith's (quasistatic) criterion does not hold in general, thus the limit evolution is not rate-independent.

VL - 28 UR - https://doi.org/10.1007/s00332-017-9407-0 ER - TY - JOUR T1 - Quasi-periodic solutions for quasi-linear generalized KdV equations JF - Journal of Differential Equations Y1 - 2017 A1 - Filippo Giuliani KW - KAM for PDE's KW - KdV KW - Nash–Moser theory KW - Quasi-linear PDE's KW - Quasi-periodic solutions AB -We prove the existence of Cantor families of small amplitude, linearly stable, quasi-periodic solutions of quasi-linear autonomous Hamiltonian generalized KdV equations. We consider the most general quasi-linear quadratic nonlinearity. The proof is based on an iterative Nash–Moser algorithm. To initialize this scheme, we need to perform a bifurcation analysis taking into account the strongly perturbative effects of the nonlinearity near the origin. In particular, we implement a weak version of the Birkhoff normal form method. The inversion of the linearized operators at each step of the iteration is achieved by pseudo-differential techniques, linear Birkhoff normal form algorithms and a linear KAM reducibility scheme.

VL - 262 UR - http://www.sciencedirect.com/science/article/pii/S0022039617300487 ER - TY - JOUR T1 - Quasistatic crack growth based on viscous approximation: a model with branching and kinking JF - Nonlinear Differential Equations and Applications NoDEA Y1 - 2017 A1 - Vito Crismale A1 - Giuliano Lazzaroni AB -Employing the technique of vanishing viscosity and time rescaling, we show the existence of quasistatic evolutions of cracks in brittle materials in the setting of antiplane shear. The crack path is not prescribed a priori and is chosen in an admissible class of piecewise regular sets that allows for branching and kinking.

VL - 24 UR - https://doi.org/10.1007/s00030-016-0426-6 ER - TY - JOUR T1 - A quadratic interaction estimate for conservation laws: motivations, techniques and open problems JF - Bulletin of the Brazilian Mathematical Society, New Series Y1 - 2016 A1 - Stefano Modena AB -In a series of joint works with S. Bianchini [3, 4, 5], we proved a quadratic interaction estimate for general systems of conservation laws. Aim of this paper is to present the results obtained in the three cited articles [3, 4, 5], discussing how they are related with the general theory of hyperbolic conservation laws. To this purpose, first we explain why this quadratic estimate is interesting, then we give a brief overview of the techniques we used to prove it and finally we present some related open problems.

VL - 47 UR - https://doi.org/10.1007/s00574-016-0171-9 ER - TY - JOUR T1 - Quadratic interaction estimate for hyperbolic conservation laws, an overview JF - Contemporary Mathematics. Fundamental Directions Y1 - 2016 A1 - Stefano Modena PB - Peoples' Friendship University of Russia VL - 59 ER - TY - THES T1 - Qualitative properties and construction of solutions to some semilinear elliptic PDEs Y1 - 2016 A1 - Matteo Rizzi KW - moving planes method, maximum principle, Lyapunov-Schmidt reduction, Willmore surfaces, Otha-Kawasaki functional AB - This thesis is devoted to the study of elliptic equations. On the one hand, we study some qualitative properties, such as symmetry of solutions, on the other hand we explicitly construct some solutions vanishing near some fixed manifold. The main techniques are the moving planes method, in order to investigate the qualitative properties and the Lyapunov-Schmidt reduction. PB - SISSA U1 - 35500 U5 - MAT/05 ER - TY - RPRT T1 - Quasi-static hydraulic crack growth driven by Darcy's law Y1 - 2016 A1 - Stefano Almi AB -In the framework of rate independent processes, we present a variational model of quasi-static crack growth in hydraulic fracture. We first introduce the energy functional and study the equilibrium conditions of an unbounded linearly elastic body subject to a remote strain ε ∈ R and with a sufficiently regular crack Γ filled by a volume V of incompressible fluid. In particular, we are able to find the pressure p of the fluid inside the crack as a function of Γ, V , and ε. Then, we study the problem of quasi-static evolution for our model, imposing that the fluid volume V and the fluid pressure p are related by Darcy’s law. We show the existence of such an evolution, and we prove that it satisfies a weak notion of the so-called Griffith’s criterion.

UR - http://urania.sissa.it/xmlui/handle/1963/35198 U1 - 35492 U2 - Mathematics U4 - 1 U5 - MAT/05 ER - TY - JOUR T1 - Quadratic Interaction Functional for General Systems of Conservation Laws JF - Communications in Mathematical Physics Y1 - 2015 A1 - Stefano Bianchini A1 - Stefano Modena AB -For the Glimm scheme approximation to the solution of the system of conservation laws in one space dimension with initial data u 0 with small total variation, we prove a quadratic (w.r.t. Tot. Var. ( u 0)) interaction estimate, which has been used in the literature for stability and convergence results. No assumptions on the structure of the flux f are made (apart from smoothness), and this estimate is the natural extension of the Glimm type interaction estimate for genuinely nonlinear systems. More precisely, we obtain the following results: a new analysis of the interaction estimates of simple waves;

VL - 338 ER - TY - JOUR T1 - On a quadratic functional for scalar conservation laws JF - Journal of Hyperbolic Differential Equations Y1 - 2014 A1 - Stefano Bianchini A1 - Stefano Modena AB -We prove a quadratic interaction estimate for approximate solutions to scalar conservation laws obtained by the wavefront tracking approximation or the Glimm scheme. This quadratic estimate has been used in the literature to prove the convergence rate of the Glimm scheme.

PB - World Scientific Publishing VL - 11 UR - http://arxiv.org/abs/1311.2929 IS - 2 U1 - 34903 U2 - Mathematics U4 - 1 ER - TY - JOUR T1 - Quadratic interaction functional for systems of conservation laws: a case study JF - Bulletin of the Institute of Mathematics of Academia Sinica (New Series) Y1 - 2014 A1 - Stefano Bianchini A1 - Stefano Modena VL - 9 UR - https://w3.math.sinica.edu.tw/bulletin_ns/20143/2014308.pdf ER - TY - JOUR T1 - Quantum dimension and quantum projective spaces Y1 - 2014 A1 - Marco Matassa AB - We show that the family of spectral triples for quantum projective spaces introduced by D'Andrea and Dbrowski, which have spectral dimension equal to zero, can be reconsidered as modular spectral triples by taking into account the action of the element K2por its inverse. The spectral dimension computed in this sense coincides with the dimension of the classical projective spaces. The connection with the well known notion of quantum dimension of quantum group theory is pointed out. PB - Institute of Mathematics UR - http://urania.sissa.it/xmlui/handle/1963/34764 U1 - 34991 U2 - Physics U4 - 2 ER - TY - JOUR T1 - Quantum gauge symmetries in noncommutative geometry Y1 - 2014 A1 - Jyotishman Bhowmick A1 - Francesco D'Andrea A1 - Biswarup Krishna Das A1 - Ludwik Dabrowski AB - We discuss generalizations of the notion of i) the group of unitary elements of a (real or complex) finite-dimensional C*-algebra, ii) gauge transformations and iii) (real) automorphisms in the framework of compact quantum group theory and spectral triples. The quantum analogue of these groups are defined as universal (initial) objects in some natural categories. After proving the existence of the universal objects, we discuss several examples that are of interest to physics, as they appear in the noncommutative geometry approach to particle physics: in particular, the C*-algebras M n(R), Mn(C) and Mn(H), describing the finite noncommutative space of the Einstein-Yang-Mills systems, and the algebras A F = C H M3 (C) and Aev = H H M4(C), that appear in Chamseddine-Connes derivation of the Standard Model of particle physics coupled to gravity. As a byproduct, we identify a "free" version of the symplectic group Sp.n/ (quaternionic unitary group). PB - European Mathematical Society Publishing House UR - http://urania.sissa.it/xmlui/handle/1963/34897 U1 - 35182 U2 - Mathematics U4 - 1 ER - TY - JOUR T1 - Quasi-static crack growth in hydraulic fracture JF - Nonlinear Analysis Y1 - 2014 A1 - Stefano Almi A1 - Gianni Dal Maso A1 - Rodica Toader AB -We present a variational model for the quasi-static crack growth in hydraulic fracture in the framework of the energy formulation of rate-independent processes. The cracks are assumed to lie on a prescribed plane and to satisfy a very weak regularity assumption.

PB - Elsevier VL - 109 UR - http://hdl.handle.net/20.500.11767/17350 IS - Nov U1 - 34741 U2 - Mathematics U4 - 1 U5 - MAT/05 ER - TY - JOUR T1 - Quasistatic Evolution in Perfect Plasticity as Limit of Dynamic Processes JF - Journal of Dynamics and Differential Equations Y1 - 2014 A1 - Gianni Dal Maso A1 - Riccardo Scala AB -We introduce a model of dynamic visco-elasto-plastic evolution in the linearly elastic regime and prove an existence and uniqueness result. Then we study the limit of (a rescaled version of) the solutions when the data vary slowly. We prove that they converge, up to a subsequence, to a quasistatic evolution in perfect plasticity.

VL - 26 UR - https://doi.org/10.1007/s10884-014-9409-7 ER - TY - JOUR T1 - Quasistatic evolution models for thin plates arising as low energy Γ-limits of finite plasticity JF - Mathematical Models and Methods in Applied Sciences Y1 - 2014 A1 - Elisa Davoli AB -In this paper we deduce by $\Gamma$-convergence some partially and fully linearized quasistatic evolution models for thin plates, in the framework of finite plasticity. Denoting by $\epsilon$ the thickness of the plate, we study the case where the scaling factor of the elasto-plastic energy is of order $\epsilon^{2 \alpha -2}$, with $\alpha\geq 3$. These scalings of the energy lead, in the absence of plastic dissipation, to the Von Kármán and linearized Von Kármán functionals for thin plates. We show that solutions to the three-dimensional quasistatic evolution problems converge, as the thickness of the plate tends to zero, to a quasistatic evolution associated to a suitable reduced model depending on $\alpha$.

VL - 24 UR - https://doi.org/10.1142/S021820251450016X ER - TY - JOUR T1 - Quadratic cohomology Y1 - 2013 A1 - Andrei A. Agrachev AB - We study homological invariants of smooth families of real quadratic forms as\r\na step towards a \"Lagrange multipliers rule in the large\" that intends to\r\ndescribe topology of smooth vector functions in terms of scalar Lagrange\r\nfunctions. PB - SISSA N1 - 24 pages U1 - 6456 U2 - Mathematics U4 - 1 U5 - MAT/03 GEOMETRIA ER - TY - JOUR T1 - Quasi-periodic solutions with Sobolev regularity of NLS on Td with a multiplicative potential JF - Journal of the European Mathematical Society Y1 - 2013 A1 - Massimiliano Berti A1 - Philippe Bolle AB - We prove the existence of quasi-periodic solutions for Schrödinger equations with a multiplicative potential on Td , d ≥ 1, finitely differentiable nonlinearities, and tangential frequencies constrained along a pre-assigned direction. The solutions have only Sobolev regularity both in time and space. If the nonlinearity and the potential are C∞ then the solutions are C∞. The proofs are based on an improved Nash-Moser iterative scheme, which assumes the weakest tame estimates for the inverse linearized operators ("Green functions") along scales of Sobolev spaces. The key off-diagonal decay estimates of the Green functions are proved via a new multiscale inductive analysis. The main novelty concerns the measure and "complexity" estimates. © European Mathematical Society 2013. VL - 15 N1 - cited By (since 1996)5 ER - TY - JOUR T1 - A quasistatic evolution model for perfectly plastic plates derived by Γ-convergence JF - Annales de l'Institut Henri Poincare (C) Non Linear Analysis Y1 - 2013 A1 - Elisa Davoli A1 - Maria Giovanna Mora KW - -convergence KW - Perfect plasticity KW - Prandtl–Reuss plasticity KW - Quasistatic evolution KW - Rate-independent processes KW - Thin plates AB -The subject of this paper is the rigorous derivation of a quasistatic evolution model for a linearly elastic–perfectly plastic thin plate. As the thickness of the plate tends to zero, we prove via Γ-convergence techniques that solutions to the three-dimensional quasistatic evolution problem of Prandtl–Reuss elastoplasticity converge to a quasistatic evolution of a suitable reduced model. In this limiting model the admissible displacements are of Kirchhoff–Love type and the stretching and bending components of the stress are coupled through a plastic flow rule. Some equivalent formulations of the limiting problem in rate form are derived, together with some two-dimensional characterizations for suitable choices of the data.

VL - 30 UR - http://www.sciencedirect.com/science/article/pii/S0294144912001035 ER - TY - JOUR T1 - Quasistatic evolution for Cam-Clay plasticity: properties of the viscosity solution JF - Calculus of variations and partial differential equations 44 (2012) 495-541 Y1 - 2012 A1 - Gianni Dal Maso A1 - Antonio DeSimone A1 - Francesco Solombrino AB -Cam-Clay plasticity is a well established model for the description of the mechanics of fine grained soils. As solutions can develop discontinuities in time, a weak notion of solution, in terms of a rescaled time s , has been proposed in [8] to give a meaning to this discontinuous evolution. In this paper we first prove that this rescaled evolution satisfies the flow-rule for the rate of plastic strain, in a suitable measure-theoretical sense. In the second part of the paper we consider the behavior of the evolution in terms of the original time variable t . We prove that the unrescaled solution satisfies an energy-dissipation balance and an evolution law for the internal variable, which can be expressed in terms of integrals depending only on the original time. Both these integral identities contain terms concentrated on the jump times, whose size can only be determined by looking at the rescaled formulation.

PB - Springer UR - http://hdl.handle.net/1963/3900 U1 - 809 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution in non-associative plasticity - the cap models JF - SIAM Journal on Mathematical Analysis 44, nr. 1 (2012) 245-292 Y1 - 2012 A1 - Jean-Francois Babadjian A1 - Gilles A. Francfort A1 - Maria Giovanna Mora KW - Elasto-plasticity AB - Non-associative elasto-plasticity is the working model of plasticity for soil and rocks mechanics. Yet, it is usually viewed as non-variational. In this work, we prove a contrario the existence of a variational evolution for such a model under a natural capping assumption on the hydrostatic stresses and a less natural mollification of the stress admissibility constraint. The obtained elasto-plastic evolution is expressed for times that are conveniently rescaled. PB - SIAM UR - http://hdl.handle.net/1963/4139 U1 - 3879 U2 - Mathematics U3 - Functional Analysis and Applications U4 - -1 ER - TY - RPRT T1 - Q-factorial Laurent rings Y1 - 2011 A1 - Ugo Bruzzo A1 - Antonella Grassi AB - Dolgachev proved that, for any field k, the ring naturally associated to a\\r\\ngeneric Laurent polynomial in d variables, $d \\\\geq 4$, is factorial. We prove a\\r\\nsufficient condition for the ring associated to a very general complex Laurent\\r\\npolynomial in d=3 variables to be Q-factorial. PB - SISSA UR - http://hdl.handle.net/1963/4183 N1 - 5 pages U1 - 3907 U2 - Mathematics U3 - Mathematical Physics U4 - -1 ER - TY - JOUR T1 - Quantum Geometry on Quantum Spacetime: Distance, Area and Volume Operators JF - Commun. Math. Phys. 308 (2011) 567-589 Y1 - 2011 A1 - Dorothea Bahns A1 - Sergio Doplicher A1 - Klaus Fredenhagen A1 - Gherardo Piacitelli AB - We develop the first steps towards an analysis of geometry on the quantum\\r\\nspacetime proposed in Doplicher et al. (Commun Math Phys 172:187–220, 1995). The homogeneous elements of the universal differential algebra are naturally identified with operators living in tensor powers of Quantum Spacetime; this allows us to compute their spectra. In particular, we consider operators that can be interpreted as distances, areas, 3- and 4-volumes. The Minkowski distance operator between two independent events is shown to have pure Lebesgue spectrum with infinite multiplicity. The Euclidean distance operator is shown to have spectrum bounded below by a constant of the order of the Planck length. The corresponding statement is proved also for both the space-space and space-time area operators, as well as for the Euclidean length of the vector representing the 3-volume operators. However, the space 3-volume operator (the time component of that vector) is shown to have spectrum equal to the whole complex plane. All these operators are normal, while the distance operators are also selfadjoint. The Lorentz invariant spacetime volume operator, representing the 4- volume spanned by five\\r\\nindependent events, is shown to be normal. Its spectrum is pure point with a\\r\\nfinite distance (of the order of the fourth power of the Planck length) away\\r\\nfrom the origin. The mathematical formalism apt to these problems is developed and its relation to a general formulation of Gauge Theories on Quantum Spaces is outlined. As a byproduct, a Hodge Duality between the absolute differential and the Hochschild boundary is pointed out. PB - Springer UR - http://hdl.handle.net/1963/5203 U1 - 5025 U2 - Mathematics U3 - Mathematical Physics U4 - -1 ER - TY - RPRT T1 - Quantum Hitchin Systems via beta-deformed Matrix Models Y1 - 2011 A1 - Giulio Bonelli A1 - Kazunobu Maruyoshi A1 - Alessandro Tanzini AB -We study the quantization of Hitchin systems in terms of beta-deformations of generalized matrix models related to conformal blocks of Liouville theory on punctured Riemann surfaces. We show that in a suitable limit, corresponding to the Nekrasov-Shatashvili one, the loop equations of the matrix model reproduce the Hamiltonians of the quantum Hitchin system on the sphere and the torus with marked points. The eigenvalues of these Hamiltonians are shown to be the epsilon1-deformation of the chiral observables of the corresponding N=2 four ndimensional gauge theory. Moreover, we find the exact wave-functions in terms of the matrix model representation of the conformal blocks with degenerate field insertions.

PB - SISSA UR - http://hdl.handle.net/1963/4181 N1 - 29 pages; v2. refs. added and typos corrected U1 - 3904 U2 - Physics U3 - Elementary Particle Theory U4 - -1 ER - TY - JOUR T1 - Quantum Isometries of the finite noncommutative geometry of the Standard Model JF - Commun. Math. Phys. 307:101-131, 2011 Y1 - 2011 A1 - Jyotishman Bhowmick A1 - Francesco D'Andrea A1 - Ludwik Dabrowski AB - We compute the quantum isometry group of the finite noncommutative geometry F describing the internal degrees of freedom in the Standard Model of particle physics. We show that this provides genuine quantum symmetries of the spectral triple corresponding to M x F where M is a compact spin manifold. We also prove that the bosonic and fermionic part of the spectral action are preserved by these symmetries. PB - Springer UR - http://hdl.handle.net/1963/4906 U1 - 4688 U2 - Mathematics U3 - Mathematical Physics U4 - -1 ER - TY - JOUR T1 - Quasiconvex envelopes of energies for nematic elastomers in the small strain regime and applications JF - Journal of the Mechanics and Physics of Solids 59 (2011) 787-803 Y1 - 2011 A1 - Pierluigi Cesana A1 - Antonio DeSimone AB - We provide some explicit formulas for the quasiconvex envelope of energy densities for nematic elastomers in the small strain regime and plane strain conditions. We then demonstrate their use as a powerful tool for the interpretation of mechanical experiments. UR - http://hdl.handle.net/1963/4065 U1 - 337 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic crack evolution for a cohesive zone model with different response to loading and unloading: a Young measures approach JF - ESAIM: COCV 17 (2011) 1-27 Y1 - 2011 A1 - Filippo Cagnetti A1 - Rodica Toader AB - A new approach to irreversible quasistatic fracture growth is given, by means of Young measures. The study concerns a cohesive zone model with prescribed crack path, when the material gives different responses to loading and unloading phases. In the particular situation of constant unloading response, the result contained in [6] is recovered. In this case, the convergence of the discrete time approximations is improved. PB - Cambridge University Press / EDP Sciences UR - http://hdl.handle.net/1963/2355 U1 - 1662 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic crack growth in finite elasticity with Lipschitz data JF - {ANNALI DI MATEMATICA PURA ED APPLICATA} Y1 - 2011 A1 - Giuliano Lazzaroni KW - Brittle fracture KW - Crack propagation KW - Energy minimization KW - Finite elasticity KW - free-discontinuity problems KW - Griffith's criterion KW - Non-interpenetration} KW - Polyconvexity KW - Quasistatic evolution KW - Rate-independent processes KW - {Variational models AB -{We extend the recent existence result of Dal Maso and Lazzaroni (Ann Inst H Poincare Anal Non Lineaire 27:257-290, 2010) for quasistatic evolutions of cracks in finite elasticity, allowing for boundary conditions and external forces with discontinuous first derivatives.}

PB - {SPRINGER HEIDELBERG} CY - {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY} VL - {190} ER - TY - JOUR T1 - Quasistatic evolution for Cam-Clay plasticity: a weak formulation via viscoplastic regularization and time rescaling JF - Calculus of Variations and Partial Differential Equations 40 (2011) 125-181 Y1 - 2011 A1 - Gianni Dal Maso A1 - Antonio DeSimone A1 - Francesco Solombrino KW - Cam-Clay plasticity AB -Cam-Clay nonassociative plasticity exhibits both hardening and softening behaviour, depending on the loading. For many initial data the classical formulation of the quasistatic evolution problem has no smooth solution. We propose here a notion of generalized solution, based on a viscoplastic approximation. To study the limit of the viscoplastic evolutions we rescale time, in such a way that the plastic strain is uniformly Lipschitz with respect to the rescaled time. The limit of these rescaled solutions, as the viscosity parameter tends to zero, is characterized through an energy-dissipation balance, that can be written in a natural way using the rescaled time. As shown in [4] and [6], the proposed solution may be discontinuous with respect to the original time. Our formulation allows to compute the amount of viscous dissipation occurring instantaneously at each discontinuity time.

PB - Springer UR - http://hdl.handle.net/1963/3670 U1 - 635 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution of sessile drops and contact angle hysteresis JF - Arch. Rational Mech. Anal. 202 (2011) 295-348 Y1 - 2011 A1 - Giovanni Alberti A1 - Antonio DeSimone AB - We consider the classical model of capillarity coupled with a rate-independent dissipation mechanism due to frictional forces acting on the contact line, and prove the existence of quasistatic evolutions with prescribed initial configuration. We also discuss in detail some explicit solutions to show that the model does account for contact angle hysteresis, and to compare its predictions with experimental observations. PB - Springer UR - http://hdl.handle.net/1963/4912 U1 - 4693 U2 - Mathematics U3 - Functional Analysis and Applications U4 - -1 ER - TY - RPRT T1 - Quantum Spacetime: a Disambiguation Y1 - 2010 A1 - Gherardo Piacitelli AB - We review an approach to non-commutative geometry, where models are constructed by quantisation of the coordinates. In particular we focus on the full DFR model and its irreducible components; the (arbitrary) restriction to a particular irreducible component is often referred to as the \\\"canonical quantum spacetime\\\". The aim is to distinguish and compare the approaches under various points of view, including motivations, prescriptions for quantisation, the choice of mathematical objects and concepts, approaches to dynamics and to covariance. Some incorrect statements as \\\"universality of Planck scale conflicts with Lorentz-Fitzgerald contraction and requires a modification of covariance\\\", or \\\"stability of the geometric background requires an absolute lower bound of (\\\\Delta x^\\\\mu)\\\", or \\\"violations of unitarity are due to time/space non-commutativity\\\" are put in context, and discussed. UR - http://hdl.handle.net/1963/3864 U1 - 845 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Quasistatic crack growth in elasto-plastic materials: the two-dimensional case JF - Arch. Ration. Mech. Anal. 196 (2010) 867-906 Y1 - 2010 A1 - Gianni Dal Maso A1 - Rodica Toader AB - We study a variational model for the quasistatic evolution of elasto-plastic materials with cracks in the case of planar small strain associative elasto-plasticity. UR - http://hdl.handle.net/1963/2964 U1 - 1736 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic crack growth in finite elasticity with non-interpenetration JF - Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 257-290 Y1 - 2010 A1 - Gianni Dal Maso A1 - Giuliano Lazzaroni AB -We present a variational model to study the quasistatic growth of brittle cracks in hyperelastic materials, in the framework of finite elasticity, taking\\ninto account the non-interpenetration condition.

UR - http://hdl.handle.net/1963/3397 U1 - 935 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution for Cam-Clay plasticity: the spatially homogeneous case JF - Netw. Heterog. Media 5 (2010) 97-132 Y1 - 2010 A1 - Gianni Dal Maso A1 - Francesco Solombrino KW - Cam-Clay plasticity AB -We study the spatially uniform case of the problem of quasistatic evolution in small strain nonassociative elastoplasticity (Cam-Clay model). Through the introdution of a viscous approximation, the problem reduces to determine the limit behavior of the solutions of a singularly perturbed system of ODE\\\'s in a finite dimensional Banach space. Depending on the sign of two explicit scalar indicators, we see that the limit dynamics presents, under quite generic assumptions, the alternation of three possible regimes: the elastic regime, when the limit equation is just the equation of linearized elasticity, the slow dynamics, when the strain evolves smoothly on the yield surface and plastic flow is produced, and the fast dynamics, which may happen only in the softening regime, where\\nviscous solutions exhibit a jump across a heteroclinic orbit of an auxiliary system.

UR - http://hdl.handle.net/1963/3671 U1 - 634 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution for plasticity with softening: The spatially homogeneous case JF - Discrete & Continuous Dynamical Systems - A Y1 - 2010 A1 - Francesco Solombrino KW - plasticity with softening KW - rate independent processes AB -The spatially uniform case of the problem of quasistatic evolution in small strain associative elastoplasticity with softening is studied. Through the introdution of a viscous approximation, the problem reduces to determine the limit behaviour of the solutions of a singularly perturbed system of ODE's in a finite dimensional Banach space. We see that the limit dynamics presents, for a generic choice of the initial data, the alternation of three possible regimes (elastic regime, slow dynamics, fast dynamics), which is determined by the sign of two scalar indicators, whose explicit expression is given.

VL - 27 UR - http://aimsciences.org//article/id/4c2301d8-f553-493e-b672-b4f76a3ede2f ER - TY - JOUR T1 - Quasistatic evolution for Cam-Clay plasticity: examples of spatially homogeneous solutions JF - Math. Models Methods Appl. Sci. 19 (2009) 1643-1711 Y1 - 2009 A1 - Gianni Dal Maso A1 - Antonio DeSimone AB - We study a quasistatic evolution problem for Cam-Clay plasticity under a special loading program which leads to spatially homogeneous solutions. Under some initial conditions, the solutions exhibit a softening behaviour and time discontinuities.\\nThe behavior of the solutions at the jump times is studied by a viscous approximation. UR - http://hdl.handle.net/1963/3395 U1 - 937 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution problems for nonhomogeneous elastic plastic materials JF - J. Convex Anal. Y1 - 2009 A1 - Francesco Solombrino AB -The paper studies the quasistatic evolution for elastoplastic materials when the yield surface depends on the position in the reference configuration. The main results are obtained when the yield surface is continuous with respect to the space variable. The case of piecewise constant dependence is also considered. The evolution is studied in the framework of the variational formulation for rate independent problems developed by Mielke. The results are proved by adapting the arguments introduced for a constant yield surface, using some properties of convex valued semicontinuous multifunctions. A strong formulation of the problem is also obtained, which includes a pointwise version of the plastic flow rule. Some examples are considered, which show that strain concentration may occur as a consequence of a nonconstant yield surface.

VL - 16 ER - TY - RPRT T1 - Quasistatic crack growth for a cohesive zone model with prescribed crack path Y1 - 2007 A1 - Gianni Dal Maso A1 - Chiara Zanini AB - In this paper we study the quasistatic crack growth for a cohesive zone model. We assume that the crack path is prescribed and we study the time evolution of the crack in the framework of the variational theory of rate-independent processes. JF - Proc. Roy. Soc. Edinburgh Sect. A 137 (2007) 253-279 UR - http://hdl.handle.net/1963/1686 U1 - 2447 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution problems for pressure-sensitive plastic materials JF - Milan J. Math. 75 (2007) 117-134 Y1 - 2007 A1 - Gianni Dal Maso A1 - Alexey Demyanov A1 - Antonio DeSimone AB - We study quasistatic evolution problems for pressure-sensitive plastic materials in the context of small strain associative perfect plasticity. UR - http://hdl.handle.net/1963/1962 U1 - 2231 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Q-curvature flow on S^4 JF - J. Differential Geom. 73 (2006) 1-44 Y1 - 2006 A1 - Andrea Malchiodi A1 - Michael Struwe UR - http://hdl.handle.net/1963/2193 U1 - 2051 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quantisation of bending flows JF - Czechoslovak Journal of Physics 56 (2006), n. 10-11, 1143-1148 Y1 - 2006 A1 - Gregorio Falqui A1 - Fabio Musso AB - We briefly review the Kapovich-Millson notion of Bending flows as an integrable system on the space of polygons in ${\\\\bf R}^3$, its connection with a specific Gaudin XXX system, as well as the generalisation to $su(r), r>2$. Then we consider the quantisation problem of the set of Hamiltonians pertaining to the problem, quite naturally called Bending Hamiltonians, and prove that their commutativity is preserved at the quantum level. UR - http://hdl.handle.net/1963/2537 U1 - 1582 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Quasi-periodic solutions of completely resonant forced wave equations JF - Comm. Partial Differential Equations 31 (2006) 959 - 985 Y1 - 2006 A1 - Massimiliano Berti A1 - Michela Procesi AB - We prove existence of quasi-periodic solutions with two frequencies of completely resonant, periodically forced nonlinear wave equations with periodic spatial boundary conditions. We consider both the cases the forcing frequency is: (Case A) a rational number and (Case B) an irrational number. UR - http://hdl.handle.net/1963/2234 U1 - 2010 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasistatic evolution problems for linearly elastic-perfectly plastic materials JF - Arch. Ration. Mech. Anal. 180 (2006) 237-291 Y1 - 2006 A1 - Gianni Dal Maso A1 - Antonio DeSimone A1 - Maria Giovanna Mora AB - The problem of quasistatic evolution in small strain associative elastoplasticity is studied in the framework of the variational theory for rate-independent processes. Existence of solutions is proved through the use of incremental variational problems in spaces of functions with bounded deformation. This provides a new approximation result for the solutions of the quasistatic evolution problem, which are shown to be absolutely continuous in time. Four equivalent formulations of the problem in rate form are derived. A strong formulation of the flow rule is obtained by introducing a precise definition of the stress on the singular set of the plastic strain. UR - http://hdl.handle.net/1963/2129 U1 - 2114 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasi-periodic oscillations for wave equations under periodic forcing JF - Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 109-116 Y1 - 2005 A1 - Massimiliano Berti A1 - Michela Procesi PB - Accademia Nazionale dei Lincei UR - http://hdl.handle.net/1963/4583 U1 - 4350 U2 - Mathematics U3 - Functional Analysis and Applications U4 - -1 ER - TY - JOUR T1 - Quasistatic Crack Growth in Nonlinear Elasticity JF - Arch. Ration. Mech. Anal. 176 (2005) 165-225 Y1 - 2005 A1 - Gianni Dal Maso A1 - Gilles A. Francfort A1 - Rodica Toader AB - In this paper, we prove a new existence result for a variational model of crack growth in brittle materials proposed in [15]. We consider the case of $n$-dimensional finite elasticity, for an arbitrary $n\\\\ge1$, with a quasiconvex bulk energy and with prescribed boundary deformations and applied loads, both depending on time. UR - http://hdl.handle.net/1963/2293 U1 - 1723 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quasi-static evolution in brittle fracture: the case of bounded solutions JF - Quad. Mat. Dip. Mat. Seconda Univ. Napoli 14 (2004) 245-266 Y1 - 2004 A1 - Gianni Dal Maso A1 - Gilles A. Francfort A1 - Rodica Toader AB - The main steps of the proof of the existence result for the quasi-static evolution of cracks in brittle materials, obtained in [7] in the vector case and for a general quasiconvex elastic energy, are presented here under the simplifying assumption that the minimizing sequences involved in the problem are uniformly bounded in $L^\\\\infty$. UR - http://hdl.handle.net/1963/2229 U1 - 2015 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - JOUR T1 - Quantum spin coverings and statistics JF - J. Phys. A 36 (2003), no. 13, 3829-3840 Y1 - 2003 A1 - Ludwik Dabrowski A1 - Cesare Reina AB - SL_q(2) at odd roots of unity q^l =1 is studied as a quantum cover of the complex rotation group SO(3,C), in terms of the associated Hopf algebras of (quantum) polynomial functions. We work out the irreducible corepresentations, the decomposition of their tensor products and a coquasitriangular structure, with the associated braiding (or statistics). As an example, the case l=3 is discussed in detail. PB - IOP Publishing UR - http://hdl.handle.net/1963/1667 U1 - 2451 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Quantum mechanics and stochastic mechanics for compatible observables at different times JF - Ann.Physics 296 (2002), no.2, 371 Y1 - 2002 A1 - Michele Correggi A1 - Giovanni Morchio PB - SISSA Library UR - http://hdl.handle.net/1963/1577 U1 - 2541 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Quantized control systems and discrete nonholonomy JF - Lagrangian and Hamiltonian Methods for Nonlinear Control : a proc. volume from the IFAC Workshop. Princeton, New Jersey, 16-18 March 2000 / ed. by N.E. Leonard, R. Ortega. - Oxford : Pergamon, 2000 Y1 - 2000 A1 - Alessia Marigo A1 - Benedetto Piccoli A1 - Antonio Bicchi PB - Elsevier SN - 0-08-043658-7 UR - http://hdl.handle.net/1963/1502 U1 - 2661 U2 - Mathematics U3 - Functional Analysis and Applications ER - TY - CHAP T1 - Quantum homogeneous spaces at roots of unity T2 - Quantization, Coherent States and Poisson Structures, Proc. XIVth Workshop on Geometric Methods in Physics, Bialowieza, Poland, 9-15 July 1995, eds. A. Strasburger,\\nS.T. Ali, J.-P. Antoine, J.-P. Gazeau , A. Odzijewicz, Polish Scientific Publisher PWN 1 Y1 - 1995 A1 - Cesare Reina A1 - Alessandro Zampa JF - Quantization, Coherent States and Poisson Structures, Proc. XIVth Workshop on Geometric Methods in Physics, Bialowieza, Poland, 9-15 July 1995, eds. A. Strasburger,\\nS.T. Ali, J.-P. Antoine, J.-P. Gazeau , A. Odzijewicz, Polish Scientific Publisher PWN 1 PB - SISSA Library UR - http://hdl.handle.net/1963/1022 U1 - 2834 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Quadratic forms for singular perturbations of the Laplacian JF - Publ. Res. Inst. Math. Sci. 26 (1990), no. 5, 803--817 Y1 - 1990 A1 - Alessandro Teta PB - SISSA Library UR - http://hdl.handle.net/1963/757 U1 - 3034 U2 - Mathematics U3 - Mathematical Physics ER -