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Sensor-less adaptive optics for Brillouin micro-spectroscopyFeb 08 2018Brillouin spectroscopy is a powerful optical technique for viscoelastic characterization of samples without contact. However, like all optical systems, Brillouin spectroscopy performances are degraded by optical aberrations, and have therefore been limited ... More

Entangled-Photon Coincidence Fluorescence ImagingDec 08 2008We extend entangled coincidence (ghost) imaging to fluorescent samples. Given the entangled photon correlation, one photon of the pair carries information on where the other photon has been absorbed and has produced fluorescence in a sample. Fluorescent ... More

Direct three-dimensional measurement of refractive index via dual photon-phonon scatteringJan 30 2019We developed a microscopy technique that can measure the local refractive index without sampling the optical phase delay of the electromagnetic radiation. To do this, we designed and experimentally demonstrated a setup with two co-localized Brillouin ... More

Distant Clock Synchronization Using Entangled Photon PairsJul 26 2004We report a proof-of-principle experiment on distant clock synchronization. Besides the achievement of picosecond resolution at 3 kilometer distance, this experiment demonstrated a novel concept for high accuracy non-local timing and positioning based ... More

Two-photon interference with thermal lightOct 27 2004Nov 08 2004The study of entangled states has greatly improved the basic understanding about two-photon interferometry. Two-photon interference is not the interference of two photons but the result of superposition among indistinguishable two-photon amplitudes. The ... More

Random Delayed-Choice Quantum Eraser via Two-Photon ImagingDec 22 2005Jun 14 2007We report on a delayed-choice quantum eraser experiment based on a two-photon imaging scheme using entangled photon pairs. After the detection of a photon which passed through a double-slit, a random delayed choice is made to erase or not erase the which-path ... More

Experimental study of the momentum correlation of a pseudo-thermal field in the photon counting regimeSep 29 2004Thermal (or pseudo-thermal) radiation has been recently proposed for imaging and interference types of experiments to simulate entangled states. We report an experimental study on the momentum correlation properties of a pseudo-thermal field in the photon ... More

Plenoptic imaging with second-order correlations of lightApr 14 2017Plenoptic imaging is a promising optical modality that simultaneously captures the location and the propagation direction of light in order to enable tridimensional imaging in a single shot. We demonstrate that it is possible to implement plenoptic imaging ... More

Remote spectral measurement using entangled photonsJul 20 2004By utilizing the frequency anticorrelation of two-photon states produced via spontaneous parametric down conversion (SPDC), the working principle of a novel remote spectrometer is demonstrated. With the help of a local scanning monochromator, the spectral ... More

Correlation plenoptic imagingApr 01 2016Jun 07 2016Plenoptic imaging is a promising optical modality that simultaneously captures the location and the propagation direction of light in order to enable three-dimensional imaging in a single shot. However, in classical imaging systems, the maximum spatial ... More

Two-photon "ghost" imaging with thermal lightJul 30 2004Feb 18 2005We report the first experimental demonstration of two-photon imaging with a pseudo-thermal source. Similarly to the case of entangled states, a two-photon Gaussian thin lens equation is observed, indicating EPR type correlation in position. We introduce ... More

Quantum simulation of the single-particle Schrodinger equationSep 11 2007Nov 30 2007The working of a quantum computer is described in the concrete example of a quantum simulator of the single-particle Schrodinger equation. We show that a register of 6-10 qubits is sufficient to realize a useful quantum simulator capable of solving in ... More

Optimal purification of a generic n-qudit stateOct 08 2008Jan 13 2009We propose a quantum algorithm for the purification of a generic mixed state $\rho$ of a $n$-qudit system by using an ancillary $n$-qudit system. The algorithm is optimal in that (i) the number of ancillary qudits cannot be reduced, (ii) the number of ... More

High-extinction VIPA-based Brillouin spectroscopy of turbid biological mediaApr 17 2016Brillouin microscopy has recently emerged as powerful technique to characterize the mechanical properties of biological tissue, cell and biomaterials. However, the potential of Brillouin microscopy is currently limited to transparent samples, because ... More

A simple representation of quantum process tomographyMay 05 2009We show that the Fano representation leads to a particularly simple and appealing form of the quantum process tomography matrix $\chi_{_F}$, in that the matrix $\chi_{_F}$ is real, the number of matrix elements is exactly equal to the number of free parameters ... More

Exploring plenoptic properties of correlation imaging with chaotic lightOct 06 2017In a setup illuminated by chaotic light, we consider different schemes that enable to perform imaging by measuring second-order intensity correlations. The most relevant feature of the proposed protocols is the ability to perform plenoptic imaging, namely ... More

Computing the distance between quantum channels: Usefulness of the Fano representationApr 23 2010The diamond norm measures the distance between two quantum channels. From an operational vewpoint, this norm measures how well we can distinguish between two channels by applying them to input states of arbitrarily large dimensions. In this paper, we ... More

Gaussian wave packets in phase space: The Fermi g_F functionOct 23 2008Dec 08 2008Any pure quantum state can be equivalently represented by means of its wave function psi(q) or of the Fermi function g_F(q,p), with q and p coordinates and conjugate momenta of the system under investigation.We show that a Gaussian wave packet can be ... More

A bird's eye view of quantum computersMar 13 2007Quantum computers are discussed in the general framework of computation, the laws of physics and the foundations of quantum mechanics.

Correlation Plenoptic Imaging With Entangled PhotonsJun 07 2016Plenoptic imaging is a novel optical technique for three-dimensional imaging in a single shot. It is enabled by the simultaneous measurement of both the location and the propagation direction of light in a given scene. In the standard approach, the maximum ... More

Probabilistic Modeling of Progressive FilteringNov 03 2016Progressive filtering is a simple way to perform hierarchical classification, inspired by the behavior that most humans put into practice while attempting to categorize an item according to an underlying taxonomy. Each node of the taxonomy being associated ... More

Fixed point theorems for metric spaces with a conical geodesic bicombingSep 05 2015We derive two fixed point theorems for a class of metric spaces that includes all Banach spaces and all complete Busemann spaces. We obtain our results by the use of a 1-Lipschitz barycenter construction and an existence result for invariant Radon probability ... More

Luna-Vust invariants of Cox rings of spherical varietiesAug 29 2016Dec 14 2016Given the Luna-Vust invariants of a spherical variety, we determine the Luna-Vust invariants of the spectrum of its Cox ring. In particular, we deduce an explicit description of the divisor class group of the Cox ring. Moreover, we obtain a combinatorial ... More

Entanglement, randomness and chaosJul 28 2008Oct 06 2008Entanglement is not only the most intriguing feature of quantum mechanics, but also a key resource in quantum information science. The entanglement content of random pure quantum states is almost maximal; such states find applications in various quantum ... More

The Multi-Branched Method of Moments for Queueing NetworksFeb 18 2009We propose a new exact solution algorithm for closed multiclass product-form queueing networks that is several orders of magnitude faster and less memory consuming than established methods for multiclass models, such as the Mean Value Analysis (MVA) algorithm. ... More

Spherical varieties with the $A_k$-propertyMar 22 2013Nov 10 2017An algebraic variety is said to have the $A_k$-property if any $k$ points are contained in some common affine open neighbourhood. A theorem of W{\l}odarczyk states that a normal variety has the $A_2$-property if and only if it admits a closed embedding ... More

Luna-Vust invariants of Cox rings and skeletons of spherical varietiesAug 29 2016Feb 27 2019Given the Luna-Vust invariants of a spherical variety, we determine the Luna-Vust invariants of the spectrum of its Cox ring. In particular, we deduce an explicit description of the divisor class group of the Cox ring. It follows that every spherical ... More

A combinatorial smoothness criterion for spherical varietiesJul 29 2013Dec 16 2014We suggest a combinatorial criterion for the smoothness of an arbitrary spherical variety using the classification of multiplicity-free spaces, generalizing an earlier result of Camus for spherical varieties of type $A$.

Computation of maximal projection constantsJan 23 2019The linear projection constant $\Pi(E)$ of a finite-dimensional real Banach space $E$ is the smallest number $C\in [0,+\infty)$ such that $E$ is a $C$-absolute retract in the category of real Banach spaces with bounded linear maps. We denote by $\Pi_n$ ... More

Anderson transition of cold atoms with synthetic spin-orbit coupling in two-dimensional speckle potentialsJul 27 2016We investigate the metal-insulator transition occurring in two dimensional (2D) systems of non- interacting atoms in the presence of artificial spin-orbit interactions and a spatially correlated dis- order generated by laser speckles. Based on a high ... More

Prospects for double Higgs productionDec 14 2015A concise review of the double Higgs production channel at the LHC and at future hadron and lepton machines is presented.

Luna-Vust invariants of Cox rings of spherical varietiesAug 29 2016We determine the Luna-Vust invariants of the spectrum of the Cox ring of a (not necessarily complete) spherical variety and deduce an explicit description of the divisor class group of the Cox ring. In particular, we determine exactly when the Cox ring ... More

Diffraction-limited plenoptic imaging with correlated lightMar 10 2017Jan 16 2018Traditional optical imaging faces an unavoidable trade-off between resolution and depth of field (DOF). To increase resolution, high numerical apertures (NA) are needed, but the associated large angular uncertainty results in a limited range of depths ... More

Lipschitz extensions to finitely many pointsJul 20 2017Jul 01 2018We consider Lipschitz maps with values in quasi-metric spaces and extend such maps to finitely many points. We prove that in this context every 1-Lipschitz map admits an extension such that its Lipschitz constant is bounded from above by the number of ... More

Gauge-Higgs Unification on Flat Space RevisedOct 27 2006Models with gauge-Higgs unification on a flat space are typically affected by common problems, the main of which are the prediction of a too small top and Higgs mass and a too low compactification scale. We show how, by breaking the SO(4,1) Lorentz symmetry ... More

Exotic States in the Dynamical Casimir EffectDec 21 2013We consider the interaction of a qubit with a single mode of the quantized electromagnetic field and show that, in the ultrastrong coupling regime and when the qubit-field interaction is switched on abruptly, the dynamical Casimir effect leads to the ... More

Entanglement in heliumApr 30 2012May 01 2013Using a configuration-interaction variational method, we accurately compute the reduced, single-electron von Neumann entropy for several low-energy, singlet and triplet eigenstates of helium atom. We estimate the amount of electron-electron orbital entanglement ... More

Reconstruction of electromagnetic field states by a probe qubitMay 10 2016We propose a method to measure the quantum state of a single mode of the electromagnetic field. The method is based on the interaction of the field with a probe qubit. The qubit polarizations along coordinate axes are functions of the interaction time ... More

Non-perturbative interpretation of the Bloch vector's path beyond rotating wave approximationMay 06 2013Aug 22 2013The Bloch vector's path of a two-level system exposed to a monochromatic field exhibits, in the regime of strong coupling, complex corkscrew trajectories. By considering the infinitesimal evolution of the two-level system when the field is treated as ... More

Effects of single-qubit quantum noise on entanglement purificationMay 24 2005Nov 23 2005We study the stability under quantum noise effects of the quantum privacy amplification protocol for the purification of entanglement in quantum cryptography. We assume that the E91 protocol is used by two communicating parties (Alice and Bob) and that ... More

Fix-lines and stability domain in the vicinity of the coupled third order resonanceApr 16 2015The single particle stability in a circular accelerator is of concern especially for operational regimes involving beam storage of hours. In the proximity to a resonance this stability domain shrinks, and the phase space fragments into a jungle of exotic ... More

Sensitivity of Quantum Motion for Classically Chaotic SystemsDec 10 2001We discuss the behavior of fidelity for a classically chaotic quantum system in the metallic regime. We show the existence of a critical value of the perturbation below which the exponential decay of fidelity is determined by the width of the Breit-Wigner ... More

Asymptotically Good Convolutional CodesNov 28 2016In this paper, we construct new sequences of asymptotically good convolutional codes. These sequences are obtained from sequences of transitive, self-orthogonal and self-dual block codes that attain the Tsfasman-Vladut-Zink bound. Furthermore, by applying ... More

Screening Clouds and Majorana FermionsMar 31 2014Jun 24 2014Ken Wilson developed the Numerical Renormalization Group technique which greatly enhanced our understanding of the Kondo effect and other quantum impurity problems. Wilson's NRG also inspired Philippe Nozieres to propose the idea of a large "Kondo screening ... More

Boundary Field Theory Approach to the Renormalization of SQUID DevicesAug 27 2006Dec 14 2006We show that the quantum properties of some Josephson SQUID devices are described by a boundary sine Gordon model. Our approach naturally describes multi-junction SQUID devices and, when applied to a single junction SQUID (the rf-SQUID), it reproduces ... More

Spin fractionalization of an even number of electrons in a Quantum dotOct 26 1999An experiment is proposed of non perturbative tunneling in a Quantum dot connected to leads in a pillar configuration, which would shed light on the physics of the mesoscopic Kondo problem. We propose for the first time that what is coupled to the leads ... More

Gorenstein spherical Fano varietiesMar 12 2013Feb 12 2015We obtain a combinatorial description of Gorenstein spherical Fano varieties in terms of certain polytopes, generalizing the combinatorial description of Gorenstein toric Fano varieties by reflexive polytopes and its extension to Gorenstein horospherical ... More

A remark on contracting inverse semigroupsSep 29 2014A semi-lattice is said to be tree-like when any two of its elements are either orthogonal or comparable. Given an inverse semigroup S whose idempotent semi-lattice is tree-like, and such that all tight filters are ultra-filters, we present a necessary ... More

Manin's conjecture for certain spherical threefoldsNov 15 2016Aug 10 2018We prove Manin's conjecture on the asymptotic behavior of the number of rational points of bounded anticanonical height for a spherical threefold with canonical singularities and two infinite families of spherical threefolds with log terminal singularities. ... More

Class of hypocomplex structures on the two dimensional torusFeb 11 2019We study the H\"{o}lder solvability of a class of complex vector fields on the torus $\mathbb{T}^2$. We make use of the Theta function to associate a Cauchy-Pompeiu type integral operator. A similarity principle for the solutions of the equation $Lu=au+b\bar{u}$ ... More

Effective Action and Holography in 5D Gauge TheoriesMar 30 2007May 17 2007We apply the holographic method to 5D gauge theories on the warped interval. Our treatment includes the scalars associated with the fifth gauge field component, which appear as 4D Goldstone bosons in the holographic effective action. Applications are ... More

Propagation of numerical noise in particle-in-cell trackingMar 16 2015Jan 26 2016Particle-in-cell (PIC) is the most used algorithm to perform self-consistent tracking of intense charged particle beams. It is based on depositing macro-particles on a grid, and subsequently solving on it the Poisson equation. It is well known that PIC ... More

Dual fermionic variables and renormalization group approach to junctions of strongly interacting quantum wiresApr 02 2015Sep 17 2015Making a combined use of bosonization and fermionization techniques, we build nonlocal transformations between dual fermion operators, describing junctions of strongly interacting spinful one-dimensional quantum wires. Our approach allows for trading ... More

The dc Josephson current in a long multi-channel quantum wireJul 06 2014The dc Josephson current across a multi-channel SNS junction is computed by summing contributions from sub-gap Andreev bound states, as well as from continuum states propagating within the superconducting leads. We show that, in a long multi-channel SNS-junction, ... More

Competing Boundary Interactions in a Josephson Junction Network with an ImpurityJan 14 2010Jun 02 2010We analyze a perturbation of the boundary Sine-Gordon model where two boundary terms of different periodicities and scaling dimensions are coupled to a Kondo-like spin degree of freedom. We show that, by pertinently engineering the coupling with the spin ... More

Form factors of descendant operators in the massive Lee-Yang modelJan 21 2005The form factors of the descendant operators in the massive Lee-Yang model are determined up to level 7. This is first done by exploiting the conserved quantities of the integrable theory to generate the solutions for the descendants starting from the ... More

Conical geodesic bicombings on subsets of normed vector spacesApr 14 2016Aug 16 2016In this paper we establish existence and uniqueness results for conical geodesic bicombings on subsets of normed vector spaces. Concerning existence, we give a first example of a convex geodesic bicombing that is not consistent. Furthermore, we show that ... More

Homogeneous spherical data of orbits in spherical embeddingsDec 10 2013Dec 17 2014Let $G$ be a connected reductive complex algebraic group. Luna assigned to any spherical homogeneous space $G/H$ a combinatorial object called a homogeneous spherical datum. By a theorem of Losev, this object uniquely determines $G/H$ up to $G$-equivariant ... More

The generalized Mukai conjecture for symmetric varietiesDec 18 2014May 09 2016We associate to any complete spherical variety $X$ a certain nonnegative rational number $\wp(X)$, which we conjecture to satisfy the inequality $\wp(X) \le \operatorname{dim} X - \operatorname{rank} X$ with equality holding if and only if $X$ is isomorphic ... More

An Error Model for the Cirac-Zoller CNOT gateSep 21 2009In the framework of ion-trap quantum computing, we develop a characterization of experimentally realistic imperfections which may affect the Cirac-Zoller implementation of the CNOT gate. The CNOT operation is performed by applying a protocol of five laser ... More

Partial crossed product description of the C*-algebras associated with integral domainsOct 05 2010Oct 08 2010Recently, Cuntz and Li introduced the C^*-algebra A[R] associated to an integral domain R with finite quotients. In this paper, we show that A[R] is a partial group algebra of the group $K \rtimes K^x$ with suitable relations, where K is the field of ... More

The composite operator T\bar{T} in sinh-Gordon and a series of massive minimal modelsFeb 22 2006The composite operator T\bar{T}, obtained from the components of the energy-momentum tensor, enjoys a quite general characterization in two-dimensional quantum field theory also away from criticality. We use the form factor bootstrap supplemented by asymptotic ... More

Matrix elements of the operator T\bar{T} in integrable quantum field theoryJul 16 2004Jan 26 2005Recently A. Zamolodchikov obtained a series of identities for the expectation values of the composite operator T\bar{T} constructed from the components of the energy-momentum tensor in two-dimensional quantum field theory. We show that if the theory is ... More

Frustration of decoherence in $Y$-shaped superconducting Josephson networksOct 29 2007Jul 06 2008We examine the possibility that pertinent impurities in a condensed matter system may help in designing quantum devices with enhanced coherent behaviors. For this purpose, we analyze a field theory model describing Y- shaped superconducting Josephson ... More

Josephson current through a long quantum wireSep 03 2012Jan 16 2013The dc Josephson current through a long SNS junction receives contributions from both Andreev bound states localized in the normal region as well as from scattering states incoming from the superconducting leads. We show that in the limit of a long junction, ... More

Pairing of Cooper pairs in a Josephson junction network containing an impurityAug 06 2009Jan 14 2010We show how to induce pairing of Cooper pairs (and, thus, $4e$ superconductivity) as a result of local embedding of a quantum impurity in a Josephson network fabricable with conventional junctions. We find that a boundary double Sine-Gordon model provides ... More

Y-junction of superconducting Josephson chainsAug 20 2008Jan 21 2009We show that, for pertinent values of the fabrication and control parameters, an attractive finite coupling fixed point emerges in the phase diagram of a Y-junction of superconducting Josephson chains. The new fixed point arises only when the dimensionless ... More

An Uncertainty-Aware Approach to Optimal Configuration of Stream Processing SystemsJun 21 2016Finding optimal configurations for Stream Processing Systems (SPS) is a challenging problem due to the large number of parameters that can influence their performance and the lack of analytical models to anticipate the effect of a change. To tackle this ... More

The Discrete Composite Higgs ModelJun 14 2011Oct 14 2011We describe a concrete, predictive incarnation of the general paradigm of a composite Higgs boson, which provides a valid alternative to the standard holographic models in five space-time dimensions. Differently from the latter, our model is four-dimensional ... More

The Electroweak Phase Transition in Models with Gauge-Higgs UnificationNov 30 2005The dynamics of five dimensional Wilson line phases at finite temperature is studied in the one-loop approximation. We show that at temperatures of order $T\sim 1/L$, where L is the length of the compact space, the gauge symmetry is always restored and ... More

The Electroweak Phase Transition on Orbifolds with Gauge-Higgs UnificationFeb 28 2005Mar 11 2005The dynamics of five dimensional Wilson line phases at finite temperature is studied in the one-loop approximation. We show that at temperatures of order T \sim 1/L, where L is the length of the compact space, the gauge symmetry is always restored and ... More

Quantum Poincare' recurrences in microwave ionization of Rydberg atomsJun 28 2000We study the time dependence of the ionization probability of Rydberg atoms driven by a microwave field. The quantum survival probability follows the classical one up to the Heisenberg time and then decays inversely proportional to time, due to tunneling ... More

On the algebraic stringy Euler numberOct 12 2016Oct 28 2017We are interested in stringy invariants of singular projective algebraic varieties satisfying a strict monotonicity with respect to elementary birational modifications in the Mori program. We conjecture that the algebraic stringy Euler number is one of ... More

Some sufficient conditions for lower semicontinuity in SBD and applications to minimum problems of Fracture MechanicsDec 28 2009We provide some lower semicontinuity results in the space of special functions of bounded deformation for energies of the type $$ %\int_\O {1/2}({\mathbb C} \E u, \E u)dx + \int_{J_{u}} \Theta(u^+, u^-, \nu_{u})d \H^{N-1} \enspace, \enspace [u]\cdot \nu_u ... More

The Composite Nambu-Goldstone HiggsJun 05 2015Nov 11 2015The composite Higgs scenario, in which the Higgs emerges as a composite pseudo-Nambu-Goldstone boson, is extensively reviewed in these Notes. The material is presented in a pedagogical fashion, with great emphasis on the conceptual and technical foundations ... More

Flavor hierarchies from dynamical scalesMar 21 2016Apr 11 2016One main obstacle for any beyond the SM (BSM) scenario solving the hierarchy problem is its potentially large contributions to electric dipole moments. An elegant way to avoid this problem is to have the light SM fermions couple to the BSM sector only ... More

Scaling Properties of Long-Range Correlated Noisy SignalsMar 21 2003The Hurst coefficient $H$ of a stochastic fractal signal is estimated using the function $\sigma_{MA}^2=\frac{1}{N_{max}-n}\sum_{i=n}^{N_{max}} [y(i)-\widetilde{y}_n(i)]^2$, where $\widetilde{y}_n(i)$ is defined as $1/n \sum_{k=0}^{n-1} y(i-k)$, $n$ is ... More

A Graphic Representation of States for Quantum Copying MachinesSep 29 2006The aim of this paper is to introduce a new graphic representation of quantum states by means of a specific application: the analysis of two models of quantum copying machines. The graphic representation by diagrams of states offers a clear and detailed ... More

Anderson localization of pairs in bichromatic optical latticesJun 01 2012Oct 16 2012We investigate the formation of bound states made of two interacting atoms moving in a one dimensional (1D) quasi-periodic optical lattice. We derive the quantum phase diagram for Anderson localization of both attractively and repulsively bound pairs. ... More

Mobility edge for cold atoms in laser speckle potentialsMar 15 2014Feb 17 2015Using the transfer matrix method, we numerically compute the precise position of the mobility edge of atoms exposed to a laser speckle potential, and study its dependence vs. the disorder strength and correlation function. Our results deviate significantly ... More

Manin's conjecture for certain spherical threefoldsNov 15 2016We prove Manin's conjecture on the asymptotic behavior of the number of rational points of bounded anticanonical height for a spherical threefold with canonical singularities and two infinite families of spherical threefolds with log terminal singularities. ... More

Asymptotically Good Convolutional CodesNov 28 2016Dec 02 2016In this paper, we construct new sequences of asymptotically good convolutional codes. These sequences are obtained from sequences of transitive, self-orthogonal and self-dual block codes that attain the Tsfasman-Vladut-Zink bound. Furthermore, by applying ... More

Real fermion modes, impurity entropy, and nontrivial fixed points in the phase diagram of junctions of interacting quantum wires and topological superconductorsMar 19 2019We discuss how to extend the impurity entropy to systems with boundary interactions depending on zero-mode real fermion operators (Majorana modes as well as Klein factors). As specific applications of our method, we consider a junction between N interacting ... More

Equivariant models of spherical varietiesOct 06 2017Jan 03 2019Let $G$ be a connected semisimple group over an algebraically closed field $k$ of characteristic 0. Let $Y=G/H$ be a spherical homogeneous space of $G$, and let $Y'$ be a spherical embedding of $Y$. Let $k_0$ be a subfield of $k$. Let $G_0$ be a $k_0$ ... More

Approximate Local Limit Theorems with Effective Rate and Application to Random Walks in Random SceneryDec 12 2014We show that the Bernoulli part extraction method can be used to obtain approximate forms of the local limit theorem for sums of independent lattice valued random variables, with effective error term, that is with explicit parameters and universal constants. ... More

Realization of a two-channel Kondo model with Josephson junction networksAug 29 2013We show that- in the quantum regime- a Josephson junction rhombi chain (i.e. a Josephson junction chain made by rhombi formed by joining 4 Josephson junctions) may be effectively mapped onto a quantum Hamiltonian describing Ising spins in a transverse ... More

Topological Superconductor-Luttinger Liquid JunctionsMay 08 2013May 26 2013Experimental evidence was recently obtained for topological superconductivity in spin-orbit coupled nano wires in a magnetic field, proximate to an s-wave superconductor. When only part of the wire contacts the superconductor, a localized Majorana mode ... More

Effective Boundary Field Theory for a Josephson Junction Chain with a Weak LinkJan 17 2005We show that a finite Josephson Junction (JJ) chain, ending with two bulk superconductors, and with a weak link at its center, may be regarded as a condensed matter realization of a two-boundary Sine-Gordon model. Computing the partition function yields ... More

Robust and efficient generator of almost maximal multipartite entanglementJul 03 2007Feb 12 2008Quantum chaotic maps can efficiently generate pseudo-random states carrying almost maximal multipartite entanglement, as characterized by the probability distribution of bipartite entanglement between all possible bipartitions of the system. We show that ... More

Nucleon Form Factors from 5D SkyrmionsNov 13 2008May 16 2009Several aspects of hadron physics are well described by a simple 5D effective field theory. Baryons arise in this scenario as "large" (and therefore calculable) 5D skyrmions. We extend and refine the existing analysis of this 5D soliton, which is fairly ... More

How complex is the quantum motion?Aug 24 2008Nov 23 2008In classical mechanics the complexity of a dynamical system is characterized by the rate of local exponential instability which effaces the memory of initial conditions and leads to practical irreversibility. In striking contrast, quantum mechanics appears ... More

On the algebraic stringy Euler numberOct 12 2016We are interested in stringy invariants of singular projective algebraic varieties satisfying a strict monotonicity with respect to elementary birational modifications in the Mori program. We conjecture that the algebraic stringy Euler number is one of ... More

Existence of equivariant models of spherical homogeneous spaces and other G-varietiesOct 21 2018Let $k_0$ be a field of characteristic $0$, and fix an algebraic closure $k$ of $k_0$. Let $G$ be an algebraic $k$-group, and let $Y$ be a $G$-$k$-variety. Let $G_0$ be a $k_0$-model ($k_0$-form) of $G$. We ask whether $Y$ admits a $G_0$-equivariant $k_0$-model. ... More

Hamiltonian theory of the strongly-coupled limit of the Kondo problem in the overscreened caseJul 23 2004By properly generalizing Nozie`res' Fermi liquid theory, we construct an Hamiltonian approach to the scattering of conduction electrons off a spin-1/2 impurity in the ovescreneed Kondo regime, as T -> 0. We derive the S-matrix at the interacting fixed ... More

On connected quandles of prime power orderApr 29 2019May 01 2019We develop some general ideas to study connected quandles of prime power size and we classify non-affine connected quandles of size $p^3$ for $p>3$, using a combination of group theoretical and universal algebraic tools. As a byproduct we obtain a classification ... More

Local Limit Theorems in some Random models from Number TheoryFeb 20 2015We study the local limit theorem for weighted sums of Bernoulli variables. We show on examples that this is an important question in the general theory of the local limit theorem, and which turns up to be not well explored. The examples we consider arise ... More

Dynamical Casimir Effect in Quantum Information ProcessingJul 28 2014We demonstrate, in the regime of ultrastrong matter-field coupling, the strong connection between the dynamical Casimir effect (DCE) and the performance of quantum information protocols. Our results are illustrated by means of a realistic quantum communication ... More

Transfer matrix approach to the persistent current in hybrid normal-superconducting ringsJul 06 2016Nov 15 2016Using the properties of the transfer matrix of one-dimensional quantum mechanical systems, we derive a technique to exactly compute the persistent current across a hybrid normal-superconducting-mesoscopic ring pierced by a magnetic flux Phi as a single ... More

Datasets as Interacting Particle Systems: a Framework for ClusteringFeb 01 2012Jul 24 2012In this paper we propose a framework inspired by interacting particle physics and devised to perform clustering on multidimensional datasets. To this end, any given dataset is modeled as an interacting particle system, under the assumption that each element ... More

Reversible and irreversible dynamics of a qubit interacting with a small environmentNov 27 2006May 24 2007We analyze the dynamics of a system qubit interacting by means a sequence of pairwise collisions with an environment consisting of just two qubits. We show that the density operator of the qubits approaches a common time averaged equilibrium state, characterized ... More