Results for "Dario Tamascelli"

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Quantum annealing and the Schrödinger-Langevin-Kostin equationDec 03 2008We show, in the context of quantum combinatorial optimization, or quantum annealing, how the nonlinear Schr\"odinger-Langevin-Kostin equation can dynamically drive the system toward its ground state. We illustrate, moreover, how a frictional force of ... More
Quantum walks: a Markovian perspectiveJan 29 2008Jan 30 2008For a continuous-time quantum walk on a line the variance of the position observable grows quadratically in time, whereas, for its classical counterpart on the same graph, it exhibits a linear, diffusive, behaviour. A quantum walk, thus, propagates at ... More
Interacting quantum walksOct 15 2009In this work we present the quantum mechanical computer proposed by Feynman in 1985 and, since then, widely cited but seldom used. The main feature of the model is the presence of a built in clocking mechanism managing for the ordered application of the ... More
A quantum-walk-inspired adiabatic algorithm for graph isomorphismJan 07 2014We present a 2-local quantum algorithm for graph isomorphism GI based on an adiabatic protocol. By exploiting continuous-time quantum-walks, we are able to avoid a mere diffusion over all possible configurations and to significantly reduce the dimensionality ... More
Quantum Timing and Synchronization ProblemsApr 05 2005Feynman's model of a quantum computer provides an example of a continuous-time quantum walk. Its clocking mechanism is an excitation of a basically linear chain of spins with occasional controlled jumps which allow for motion on a planar graph. The spreading ... More
Dissipative dynamics of a spin system with three-body interactionJul 04 2011In this note we explicitly solve the Lindblad equation for a system of three spins with a three-body interaction, coupled to the environment by bath operators that inject or absorb spin carriers. We exemplify the properties of this solution in the context ... More
Time-dependent density functional theory for open spin chainsDec 24 2011The application of methods of time-dependent density functional theory (TDDFT) to systems of qubits provided the interesting possibility of simulating an assigned Hamiltonian evolution by means of an auxiliary Hamiltonian having different two-qubit interactions ... More
Speed and entropy of an interacting continuous time quantum walkApr 10 2006Apr 27 2006We present some dynamic and entropic considerations about the evolution of a continuous time quantum walk implementing the clock of an autonomous machine. On a simple model, we study in quite explicit terms the Lindblad evolution of the clocked subsystem, ... More
Entropy generation in a model of reversible computationOct 17 2006We present a model in which, due to the quantum nature of the signals controlling the implementation time of successive unitary computational steps, \emph{physical} irreversibility appears in the execution of a \emph{logically} reversible computation. ... More
An introduction to quantum annealingJul 05 2011Quantum Annealing, or Quantum Stochastic Optimization, is a classical randomized algorithm which provides good heuristics for the solution of hard optimization problems. The algorithm, suggested by the behaviour of quantum systems, is an example of proficuous ... More
Dynamical kickback and non commuting impurities in a spin chainFeb 25 2008Feb 27 2008In an interacting continuous time quantum walk, while the walker (the cursor) is moving on a graph, computational primitives (unitary operators associated with the edges) are applied to ancillary qubits (the register). The model with one walker was originally ... More
Grover's algorithm on a Feynman computerOct 16 2006We present an implementation of Grover's algorithm in the framework of Feynman's cursor model of a quantum computer. The cursor degrees of freedom act as a quantum clocking mechanism, and allow Grover's algorithm to be performed using a single, time-independent ... More
Noise-assisted quantum transport and computationDec 11 2012The transmission of an excitation along a spin chain can be hindered by the presence of small fixed imperfections that create trapping regions where the excitation may get caught (Anderson localization). A certain degree of noise, ensuing from the interaction ... More
Dephasing assisted transport on a biomimetic ring structureOct 13 2017We address two-level systems arranged in ring configurations affected by static disorder. In particular we investigate the role of dephasing in the transport of an excitation along the ring. We compare the efficiency of the transfer process on isotropic ... More
Efficient simulation of finite-temperature open quantum systemsNov 29 2018Chain-mapping techniques in combination with the time-dependent density matrix renormalization group are a powerful tool for the simulation of open-system quantum dynamics. For finite-temperature environments, however, this approach suffers from an unfavorable ... More
Precursors of non-MarkovianityFeb 08 2019Using the paradigm of information backflow to characterize a non-Markovian evolution, we introduce so-called precursors of non-Markovianity, i.e. necessary properties that the system and environment state must exhibit at earlier times in order for an ... More
Coherent Transport of Quantum States by Deep Reinforcement LearningJan 20 2019Some problems in physics can be handled only after a suitable \textit{ansatz }solution has been guessed. Such method is therefore resilient to generalization, resulting of limited scope. The coherent transport by adiabatic passage of a quantum state through ... More
Precursors of non-MarkovianityFeb 08 2019May 30 2019Using the paradigm of information backflow to characterize a non-Markovian evolution, we introduce so-called precursors of non-Markovianity, i.e. necessary properties that the system and environment state must exhibit at earlier times in order for an ... More
Graphics processing units accelerated semiclassical initial value representation molecular dynamicsDec 17 2013May 08 2014This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum ... More
Non-perturbative treatment of non-Markovian dynamics of open quantum systemsSep 11 2017Jan 08 2018We identify the conditions that guarantee equivalence of the reduced dynamics of an open quantum system (OQS) for two different types of environments - one a continuous bosonic environment leading to a unitary system-environment evolution and the other ... More
Which-way interference within biomimetic unit-cells for efficient energy transferAug 29 2018We show that `which-way' interference within unit-cells enhances the propagation along linear arrays made upon these basic units. As a working example, we address the exciton transfer through linear aggregates of ring-like unit cells, the latter resembling ... More
Simulating spin-boson models with trapped ionsApr 03 2017We propose a method to simulate the dynamics of spin-boson models with small crystals of trapped ions where the electronic degree of freedom of one ion is used to encode the spin while the collective vibrational degrees of freedom are employed to form ... More
Restoring Heisenberg scaling in noisy quantum metrology by monitoring the environmentMar 15 2018Nov 29 2018We study quantum frequency estimation for $N$ qubits subjected to independent Markovian noise, via strategies based on time-continuous monitoring of the environment. Both physical intuition and an extended convexity property of the quantum Fisher information ... More
Probabilistic low-rank factorization accelerates tensor network simulations of critical quantum many-body ground statesOct 04 2017We provide evidence that randomized low-rank factorization is a powerful tool for the determination of the ground state properties of low-dimensional lattice Hamiltonians through tensor network techniques. In particular, we show that randomized matrix ... More
Quantum state transfer via Bloch oscillationsNov 30 2015The realization of reliable quantum channels, able to transfer a quantum state with high fidelity, is a fundamental step in the construction of scalable quantum devices. In this paper we describe a transmission scheme based on the genuinely quantum effect ... More
Detection of squeezing by on-chip glass-integrated homodyne analyzerOct 12 2017We design and demonstrate on-chip homodyne detection operating in the quantum regime, i.e. able to detect genuine nonclassical features. Our setup exploits a glass-integrated homodyne analyzer (IHA) entirely fabricated by femtosecond laser micromachining. ... More
Non-Markovianity by undersampling in quantum optical simulatorsMay 16 2017Dec 05 2017We unveil a novel source of non-Markovianity for the dynamics of quantum systems, which appears when the system does not explore the full set of dynamical trajectories in the interaction with its environment. We term this effect non-Markovianity by undersampling ... More
Characterization of qubit chains by Feynman probesJul 20 2016Nov 16 2016We address the characterization of qubit chains and assess the performances of local measurements compared to those provided by Feynman probes, i.e. nonlocal measurements realized by coupling a single qubit regis- ter to the chain. We show that local ... More
All-optical quantum simulator of qubit noisy channelsDec 20 2016Feb 24 2017We suggest and demonstrate an all-optical quantum simulator for single-qubit noisy channels originating from the interaction with a fluctuating field. The simulator employs the polarization degree of freedom of a single photon, and exploits its spectral ... More
Optimized auxiliary oscillators for the simulation of general open quantum systemsApr 09 2019A method for the systematic construction of few-body damped harmonic oscillator networks accurately reproducing the effect of general bosonic environments in open quantum systems is presented. Under the sole assumptions of a Gaussian environment and regardless ... More
Characterization of qubit chains by Feynman probesJul 20 2016We address the characterization of qubit chains and assess the performances of local measurements compared to those provided by Feynman probes, i.e. nonlocal measurements realized by coupling a single qubit register to the chain. We show that local measurements ... More
Well-posedness of Multidimensional Diffusion Processes with Weakly Differentiable CoefficientsJul 06 2015Aug 25 2015We investigate well-posedness for martingale solutions of stochastic differential equations, under low regularity assumptions on their coefficients, widely extending some results first obtained by A. Figalli. Our main results are a very general equivalence ... More
Tempered D-modules and Borel-Moore homology vanishingApr 24 2019We characterize the tempered part of the automorphic Langlands category D-mod$(Bun_G)$ using the geometry of the big cell in the affine Grassmannian. We deduce that, for $G$ non-abelian, tempered D-modules have no de Rham cohomology with compact supports. ... More
The Golomb topology on a Dedekind domain and the group of units of its quotientsJun 24 2019We study the Golomb spaces of Dedekind domains with torsion class group. In particular, we show that a homeomorphism between two such spaces sends prime ideals into prime ideals and preserves the $P$-adic topology on $R\setminus P$. Under certain hypothesis, ... More
A remark on the Generalized Hodge ConjectureSep 27 2010Oct 09 2012Let X be a smooth, projective variety over the field of complex numbers. On the space H of its rational cohomology of degree i we have the arithmetic filtration F^p. On the other hand, on the space of cohomology of degree i of X with complex coefficients ... More
Reducibility of 1-d Schroedinger equation with time quasiperiodic unbounded perturbations, IJun 14 2016We study the Schr\"odinger equation on $\R$ with a polynomial potential behaving as $x^{2l}$ at infinity, $1\leq l\in\N$ and with a small time quasiperiodic perturbation. We prove that if the symbol of the perturbation grows at most like $(\xi^2+x^{2l})^{\beta/(2l)}$, ... More
Wilf's conjecture for numerical semigroups with large second generatorOct 25 2017We study Wilf's conjecture for numerical semigroups $S$ such that the second least generator $a_2$ of $S$ satisfies $a_2>\frac{c(S)+\mu(S)}{3}$, where $c(S)$ is the conductor and $\mu(S)$ the multiplicity of $S$. In particular, we show that for these ... More
The sets of star and semistar operations on semilocal Prüfer domainsJul 24 2017We study the sets of semistar and star operation on a semilocal Pr\"ufer domain, with an emphasis on which properties of the domain are enough to determine them. In particular, we show that these sets depend chiefly on the properties of the spectrum and ... More
Search for the θ_{13} Neutrino Mixing Angle Using Reactor Anti-NeutrinosFeb 01 2007The measurement of the last undetermined neutrino mixing angle \theta_{13} is the main goal of the future experimental research on neutrino oscillations. At present, \theta_{13} is only known to be much smaller than the two other mixing angles, \theta_{12} ... More
Nuclear Energy Density Functionals Constrained by Low-Energy QCDFeb 06 2008A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided ... More
Graviton Production by a Thermal BathJul 24 2003Thermal fluctuations in the early universe plasma and in very hot astrophysical objects are an unavoidable source of gravitational waves (GW). Differently from previous studies on the subject, we approach this problem using methods based on field theory ... More
Fractal properties of quantum spacetimeNov 10 2008Mar 25 2009We show that in general a spacetime having a quantum group symmetry has also a scale dependent fractal dimension which deviates from its classical value at short scales, a phenomenon that resembles what observed in some approaches to quantum gravity. ... More
Low-spin models for higher-spin LagrangiansMar 03 2011Higher-spin theories are most commonly modelled on the example of spin 2. While this is appropriate for the description of free irreducible spin-s particles, alternative options could be equally interesting. In particular Maxwell's equations provide the ... More
Isotropic Lifshitz point in the O(N) TheoryMar 01 2017Sep 28 2018The presence of an isotropic tricritical Lifshitz point for the O(N) scalar theory is investigated in the 1/N expansion by means of the Functional Renormalization Group equations. At leading order, the non-trivial Lifshitz point is observed if the number ... More
Implications of the discovery of a Higgs boson with a mass of 125 GeVMar 26 2014The rather precise knowledge of the mass of the Higgs boson and of its couplings has important consequences for the physical phenomena taking place at the Fermi scale. We analyze some of these implications in the most motivated frameworks for physics ... More
Orientation of non-spherical particles in an axisymmetric random flowJun 05 2012The dynamics of non-spherical rigid particles immersed in an axisymmetric random flow is studied analytically. The motion of the particles is described by Jeffery's equation; the random flow is Gaussian and has short correlation time.The stationary probability ... More
On the number of relevant operators in asymptotically safe gravityJan 18 2013May 15 2013The asymptotic safety scenario of gravity conjectures that (i) the quantum field theory of gravity exists thanks to the presence of a non-trivial ultraviolet fixed point of the renormalization group, and that (ii) the fixed point has only a finite number ... More
Digital Signal Processing Techniques for High-Speed Optical Communications LinksMar 27 2019The main topic of this thesis is the application of advanced Digital Signal Processing (DSP) techniques to high data-rate optical links. This thesis is divided in two parts: Direct-Detection systems, and Coherent systems. In the first part, it is proposed ... More
Leptoquarks in Flavour PhysicsJan 10 2018Feb 05 2018While the LHC has not directly observed any new particle so far, experimental results from LHCb, BELLE and BABAR point towards the violation of lepton flavour universality in $b\to s\ell^{+}\ell^{-}$ and $b\to c\ell\nu$. In this context, also the discrepancy ... More
BV-capacities on Wiener Spaces and Regularity of the Maximum of the Wiener ProcessApr 30 2012Jan 07 2013We define a capacity C on abstract Wiener spaces and prove that, for any u with bounded variation, the total variation measure |Du| is absolutely continuous with respect to C: this enables us to extend the usual rules of calculus in many cases dealing ... More
When the Zariski space is a Noetherian spaceJul 23 2018Jul 24 2018We characterize when the Zariski space $\mathrm{Zar}(K|D)$ (where $D$ is an integral domain, $K$ is a field containing $D$ and $D$ is integrally closed in $K$) and the set $\mathrm{Zar_{min}}(L|D)$ of its minimal elements are Noetherian spaces.
Non-compact subsets of the Zariski space of an integral domainMay 03 2017Let $V$ be a minimal valuation overring of an integral domain $D$ and let $\mathrm{Zar}(D)$ be the Zariski space of the valuation overrings of $D$. Starting from a result in the theory of semistar operations, we prove a criterion under which the set $\mathrm{Zar}(D)\setminus\{V\}$ ... More
Star operations on numerical semigroups: antichains and explicit resultsApr 11 2016We introduce an order on the set of non-divisorial ideals of a numerical semigroup $S$, and link antichains of this order with the star operations on $S$; subsequently, we use this order to find estimates on the number of star operations on $S$. We then ... More
Quantum Gravity from Simplices: Analytical Investigations of Causal Dynamical TriangulationsJul 20 2007A potentially powerful approach to quantum gravity has been developed over the last few years under the name of Causal Dynamical Triangulations. Numerical simulations have given very interesting results in the cases of two, three and four spacetime dimension. ... More
Loop group actions on categories and Whittaker invariantsOct 18 2013We develop some aspects of the theory of $D$-modules on ind-schemes of pro-finite type. These notions are used to define $D$-modules on (algebraic) loop groups and, consequently, actions of loop groups on DG categories. Let $N$ be the maximal unipotent ... More
String theory triplets and higher-spin curvaturesJan 27 2010May 05 2010Unconstrained local Lagrangians for higher-spin gauge theories are bound to involve auxiliary fields, whose integration in the partition function generates geometric, effective actions expressed in terms of curvatures. When applied to the triplets, emerging ... More
Distributed control and game design: From strategic agents to programmable machinesJan 18 2019Large scale systems are forecasted to greatly impact our future lives thanks to their wide ranging applications including cooperative robotics, mobility on demand, resource allocation, supply chain management. While technological developments have paved ... More
Loop group actions on categories and Whittaker invariantsOct 18 2013Dec 13 2017We develop some aspects of the theory of $D$-modules on ind-schemes of pro-finite type. These notions are used to define $D$-modules on (algebraic) loop groups and, consequently, actions of loop groups on DG categories. Let $N$ be the maximal unipotent ... More
Star operations on Kunz domainsMay 28 2018May 31 2018We study star operations on Kunz domains, a class of analytically irreducible, residually rational domains associated to pseudo-symmetric numerical semigroups, and we use them to refute a conjecture of Houston, Mimouni and Park. We also find an estimate ... More
Advanced Digital Signal Processing Techniques for High-Speed Optical Communications LinksMar 27 2019Apr 26 2019The main topic of this thesis is the application of advanced Digital Signal Processing (DSP) techniques to high data-rate optical links. This thesis is divided in two parts: Direct-Detection systems, and Coherent systems. In the first part, it is proposed ... More
Reducibility of 1-d Schrödinger equation with time quasiperiodic unbounded perturbations, IIJul 22 2016We study the Schr\"odinger equation on $\R$ with a potential behaving as $x^{2l}$ at infinity, $l\in[1,+\infty)$ and with a small time quasiperiodic perturbation. We prove that, if the perturbation belongs to a class of unbounded symbols including smooth ... More
BV-regularity for the Malliavin Derivative of the Maximum of the Wiener ProcessJan 07 2013We prove that, on the classical Wiener space, the random variable $\sup_{0\le t \le T} W_t$ admits a measure as second Malliavin derivative, whose total variation measure is finite and singular w.r.t.\ the Wiener measure.
Decomposition and classification of length functionsJul 17 2018We study decompositions of length functions on integral domains as sums of length functions constructed from overrings. We find a standard representation when the integral domain admits a Jaffard family, when it is Noetherian and when it is a Pr\"ufer ... More
Calculating the density of solutions of equations related to the Pólya-Ostrowski group through Markov chainsMar 12 2018Motivated by a problem in the theory of integer-valued polynomials, we investigate the natural density of the solutions of equations of the form $\theta_uu_q(n)+\theta_ww_q(n)+\theta_2\frac{n(n+1)}{2}+\theta_1n+\theta_0\equiv 0\bmod d$, where $d,q\geq ... More
The coupling of Poisson sigma models to topological backgroundsOct 17 2016We extend the coupling to the topological backgrounds, recently worked out for the 2-dimensional BF-model, to the most general Poisson sigma models. The coupling involves the choice of a Casimir function on the target manifold and modifies the BRST transformations. ... More
On the relation between local and geometric Lagrangians for higher spinsJan 21 2010Equations of motion for free higher-spin gauge fields of any symmetry can be formulated in terms of linearised curvatures. On the other hand, gauge invariance alone does not fix the form of the corresponding actions which, in addition, either contain ... More
Geometric massive higher spins and current exchangesApr 17 2008Generalised Fierz-Pauli mass terms allow to describe massive higher-spin fields on flat background by means of simple quadratic deformations of the corresponding geometric, massless Lagrangians. In this framework there is no need for auxiliary fields. ... More
Asymptotic safety goes on shellJul 15 2011Oct 12 2018It is well known in quantum field theory that the off-shell effective action depends on the gauge choice and field parametrization used in calculating it. Nevertheless, the typical scheme in which the scenario of asymptotically safe gravity is investigated ... More
A short proof of Stein's universal multiplier theoremAug 20 2014We give a short proof of Stein's universal multiplier theorem, purely by probabilistic methods, thus avoiding any use of harmonic analysis techniques (complex interpolation or transference methods).
Deligne-Lusztig duality on the stack of local systemsJun 03 2019In the setting of the geometric Langlands conjecture, we argue that the phenomenon of divergence at infinity on Bun_G (that is, the difference between $!$-extensions and $*$-extensions) is controlled, Langlands-dually, by the locus of semisimple $\check{G}$-local ... More
Mixed integer predictive control and shortest path reformulationMar 15 2010Mixed integer predictive control deals with optimizing integer and real control variables over a receding horizon. The mixed integer nature of controls might be a cause of intractability for instances of larger dimensions. To tackle this little issue, ... More
Topological properties of localizations, flat overrings and sublocalizationsMay 28 2018We study the set of localizations of an integral domain from a topological point of view, showing that it is always a spectral space and characterizing when it is a proconstructible subspace of the space of all overrings. We then study the same problems ... More
Oscillating shells: A model for a variable cosmic objectOct 23 1997A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the ... More
Asymptotic safety goes on shellJul 15 2011Nov 11 2011It is well known in quantum field theory that the off-shell effective action depends on the gauge choice and field parametrization used in calculating it. Nevertheless, the typical scheme in which the scenario of asymptotically safe gravity is investigated ... More
Asymptotic stability of ground states in some Hamiltonian PDEs with symmetryJul 28 2011Jan 15 2013We consider a ground state (soliton) of a Hamiltonian PDE. We prove that if the soliton is orbitally stable, then it is also asymptotically stable. The main assumptions are transversal nondegeneracy of the manifold of the ground states, linear dispersion ... More
Sheaves of categories with local actions of Hochschild cochainsJan 11 2018Jun 07 2018The notion of Hochschild cochains induces an assignment from $Aff$, affine DG schemes, to monoidal DG categories. We show that this assignment extends, under some appropriate finiteness conditions, to a functor $\mathbb H: Aff \to AlgBimod(DGCat)$, where ... More
Quantitative Homogenization of Differential FormsJun 20 2018We develop a quantitative theory of stochastic homogenization in the more general framework of differential forms. Inspired by recent progress in the uniformly elliptic setting, the analysis relies on the study of certain subadditive quantities. We establish ... More
The center of H(Y)Sep 22 2017Apr 13 2018Let $Y$ be a derived geometric stack defined over an algebraically closed field of characteristic zero and satisfying three technical conditions: eventual coconnectivity, perfection and local finite presentation. % For such $Y$, we consider the DG category ... More
The spectral gluing theorem revisitedApr 13 2018We strengthen the gluing theorem occurring on the spectral side of the geometric Langlands conjecture. While the latter embeds $IndCoh_N(LS_G)$ into a category glued out of 'Fourier coefficients' parametrized by standard parabolics, our refinement explicitly ... More
Essential nature of Newton's constant in unimodular gravityNov 20 2015We point out that in unimodular gravity Newton's constant is an essential coupling, i.e. it is independent of field redefinitions. We illustrate the consequences of this fact by a calculation in a standard simple approximation, showing that in this case ... More
On the extended Whittaker categoryNov 28 2014Mar 21 2019Let $G$ be a connected reductive group, with connected center, and $X$ a smooth complete curve, both defined over an algebraically closed field of characteristic zero. Let $\operatorname{Bun}_G$ denote the stack of $G$-bundles on $X$. In analogy with ... More
A game-theoretic approach to dynamic demand response managementOct 24 2014Within the realm of dynamic of \emph{smart buildings} and \emph{smart cities}, dynamic response management is playing an ever-increasing role thus attracting the attention of scientists from different disciplines. Dynamic demand response management involves ... More
Disformal invariance of second order scalar-tensor theoriesMay 12 2014The Horndeski action is the most general one involving a metric and a scalar field that leads to second-order field equations in four dimensions. Being the natural extension of the well-known scalar-tensor theories, its structure and properties are worth ... More
Quantitative homogenization of the disordered $\nabla φ$ modelOct 15 2018We study the $\nabla \phi$ model with uniformly convex Hamiltonian $\mathcal{H} (\phi) := \sum V(\nabla \phi)$ and prove a quantitative rate of convergence for the properly rescaled partition function as well as a quantitative rate of convergence for ... More
Lagrangian flows driven by $BV$ fields in Wiener spacesOct 21 2013We establish the renormalization property for essentially bounded solutions of the continuity equation associated to $BV$ fields in Wiener spaces, with values in the associated Cameron-Martin space; thus obtaining, by standard arguments, new uniqueness ... More
Zero noise limits using local timesJan 28 2013We consider a well-known family of SDEs with irregular drifts and the correspondent zero noise limits. Using (mollified) local times, we show which trajectories are selected. The approach is completely probabilistic and relies on elementary stochastic ... More
Jaffard families and localizations of star operationsOct 05 2016We generalize the concept of localization of a star operation to flat overrings; subsequently, we investigate the possibility of representing the set $\mathrm{Star}(R)$ of star operations on $R$ as the product of $\mathrm{Star}(T)$, as $T$ ranges in a ... More
Towards a classification of stable semistar operations on a Prüfer domainJul 24 2017We study stable semistar operations defined over a Pr\"ufer domain, showing that, if every ideal of a Pr\"ufer domain $R$ has only finitely many minimal primes, every such closure can be described through semistar operations defined on valuation overrings ... More
Energetic model of tumor growthDec 22 2004A macroscopic model of the tumor Gompertzian growth is proposed. This approach is based on the energetic balance among the different cell activities, described by methods of statistical mechanics and related to the growth inhibitor factors. The model ... More
Spontaneous breaking of translational invariance in non-commutative lambda phi^4 theory in two dimensionsNov 16 2007The spontaneous breaking of of translational invariance in non-commutative self-interacting scalar field theory in two dimensions is investigated by effective action techniques. The analysis confirms the existence of the stripe phase, already observed ... More
On persistence of invariant tori and a theorem by NekhoroshevNov 15 2001Mar 09 2002We give a proof of a theorem by N.N. Nekhoroshev concerning Hamiltonian systems with $n$ degrees of freedom and $s$ integrals of motion in involution, where $1 \le s \le n$. Such a theorem ensures persistence of $s$-dimensional invariant tori under suitable ... More
Deformation of a flexible polymer in a random flow with long correlation timeDec 09 2010The effects induced by long temporal correlations of the velocity gradients on the dynamics of a flexible polymer are investigated by means of theoretical and numerical analysis of the Hookean and FENE dumbbell models in a random renewing flow. For Hookean ... More
Mutations as Levy flightsMay 31 2016Jul 01 2016Data on single-nucleotide polymorphisms and large chromosomal rearrangements, coming from a long time evolution experiment with Escherichia Coli, are analyzed in order to argue that mutations along a cell lineage can be modeled as Levy flights in the ... More
On the Dirac monopole's conceptJul 05 1999Jul 06 1999The Dirac monopole is discussed in view of the gauge invariance in Quantum Electrodynamics. It is shown the monopole existence implies the violation of the gauge invariance principle. The monopole field is essentially a longitudinal field and so a mass ... More
The monopoles in the structure of the electronJun 15 1999The classical electron is presented as made up of an electric charge and two Dirac monopoles of opposite charge performing a magnetic dipole. It is discussed that a valid variational principle for this system can be defined. The Dirac quantization condition ... More
Partial sum of matrix entries of representations of the symmetric group and its asymptoticsJun 29 2016Many aspects of the asymptotics of Plancherel distributed partitions have been studied in the past fifty years, in particular the limit shape, the distribution of the longest rows, characters of the associated representation matrices of the symmetric ... More
Imposing causality on a matrix modelDec 22 2008Jun 28 2009We introduce a new matrix model that describes Causal Dynamical Triangulations (CDT) in two dimensions. In order to do so, we introduce a new, simpler definition of 2D CDT and show it to be equivalent to the old one. The model makes use of ideas from ... More
Distance Between Quantum Field Theories As A Measure Of Lorentz ViolationMay 21 2011Sep 16 2011We study the distance between symmetry-violating quantum field theories and the surface of symmetric theories. We use this notion to quantify how precise Lorentz symmetry is today, according to experimental data. The metric in parameter space is defined ... More
Slow quench dynamics of periodically driven quantum gasesMay 03 2011We study the evolution of bosons in a periodically driven optical lattice during a slow change of the driving amplitude. Both the regime of high frequency and low frequency driving are investigated. In the low frequency regime, resonant absorption of ... More
Fast delta evaluation for the Vehicle Routing Problem with Multiple Time WindowsMay 10 2019In many applications of vehicle routing, a set of time windows are feasible for each visit, giving rise to the Vehicle Routing Problem with Multiple Time Windows (VRPMTW). We argue that such disjunctions are problematic for many solution methods, and ... More