The influence of the incompressible strips on the integer quantized hall effect ( iqhe ) is...

in standard molecular beam epitaxy ( mbe ) , the crystal is grown in the direction layer by layer . however , well - established experimental techniques are able to grow materials in different crystal directions in sequential steps . as a first step a usual mbe growth process is performed then the crystal is removed from the chamber , thinned , scribed , returned to the chamber mounted at a 90 degree angle , then cleaved in - situ and regrown . this process is known as the cleaved edge overgrowth ( ceo ) technique . the ceo samples are used to investigate the edge properties of the quantum hall systems via momentum - resolved tunneling experiments , utilizing the second 2deg residing perpendicular to the hall system . these tunneling experiments show that the ceo edge provides an extreme sharp potential approximating an infinite wall . the sample structure proposed here does not involve tunneling , but rather probes the sharpness of the qhe edges via transport alone . a schematic presentation of the crystal is depicted in fig . [ fig : fig1 ] . the hall bar lies in the plane , obtained by usual mbe growth , whereas on the right hand side of the crystal an additional algaas layer is grown . this is the ceo edge and is capped by a metallic gate . the gate covers all the surface and is kept at a fixed potential . to measure the global resistances and to drive an external current through the 2deg , ohmic contacts are deposited on the top surface of the system . the voltage probe contacts are labeled by a1 , a2 , b1 and b2 to measure and , whereas the current contacts s and d denote the source and the drain . in our discussion of the visibility of the iqhe , we will describe transport in such a ceo sample . we consider a system , where at one edge ( ceo edge ) a side gate resides , meanwhile the opposing edge is defined by standard etching process . this section aims to provide necessary theoretical and experimental background , to discuss the transport properties of the

We present a theoretical and experimental framework for the transport of quantum hall systems in standard molecular beam epitaxy ( mbe ). The system is grown in the direction layer by layer, then cleaved in - situ and regrown. This process is known as the cleaded edge overgrowth ( ceo ) technique. In this paper we discuss the transport properties of the quantum hall system using momentum - resolved tunneling experiments.

the influence of the incompressible strips on the integer quantized hall effect ( iqhe ) is investigated , considering a cleaved - edge overgrown ( ceo ) sample as an experimentally realizable sharp edge system . we propose a set of experiments to clarify the distinction between the large - sample limit when bulk disorder defines the iqhe plateau width and the small - sample limit smaller than the disorder correlation length , when self - consistent edge electrostatics define the iqhe plateau wi


We propose a new lattice superfield formalism in momentum representation which accommodates species...

if we regularize massless fermions naively on a lattice , it is unavoidable that species doublers appear . since massless particles can not be put in the rest frame by means of a lorentz transformation , helicity or chirality can not be changed with a momentum change , while species doublers in different momentum region may have different helicity . therefore species doublers have to be considered as different particles . however , species doublers of chiral fermions on a lattice are usually considered as unwanted particles , the so called doubling problem , although the enlarged degree of freedom ( d.o.f . ) is customarily identified as a flavor ( taste ) d.o.f .. the equivalence of the above naive fermion formulation and the staggered fermion formulation can be shown by a spin diagonalization procedure and the staggered fermion can be transformed into the kogut - susskind type fermion formulation by considering double size lattice structure , where the flavor d.o.f . was identified . this double size structure makes it possible to have a correspondence with differential forms and then the equivalence of the staggered fermion and dirac - khler fermion on the lattice can be proved by introducing a noncommutativity between differential forms and fields . therefore all these lattice fermion formulations are exactly equivalent . in the link approach of lattice supersymmetry , the super charges are expanded on the basis of dirac matrices by the dirac - khler twisting procedure . the corresponding d.o.f . of the super charges are then exactly the same as those of fermionic species doublers and the geometric correspondence between the particles as species doublers and super multiplets is expected from the equivalence of the naive fermion and dirac - khler fermion formulations on the lattice . in other words the species doublers are necessary fields to construct the super multiplets of extended supersymmetry : in two dimensions and n=4 in four dimensions . the flavor ( tas

We study the equivalence of species doublers on a lattice by considering the dirac - khler twisting procedure. The corresponding d. O. F. Of the super charges is then exactly the same as those of fermionic species doublerosses and the geometric correspondence between the particles as species doublerons and super multiplets is expected from the asymmetry of the naive fermion and dirac fermio formulations on the latticse.

we propose a new lattice superfield formalism in momentum representation which accommodates species doublers of the lattice fermions and their bosonic counterparts as super multiplets . we explicitly show that one dimensional model with interactions has exact lie algebraic supersymmetry on the lattice for all super charges . in coordinate representation the finite difference operator is made to satisfy leibnitz rule by introducing a non local product , the `` star '' product , and the exact latt


We report the discovery of the wide l1

multiple stellar systems are important laboratories for a wide range of astrophysical phenomena , from the formation and evolution of planetary systems to the distribution of dark matter in the galaxy . stellar multiples drive novae outbursts in cataclysmic variable systems ; are useful distance ladders for star clusters in the local group ; and provide one of the few direct means of measuring stellar mass . the production of multiples is inherent to the star formation process itself , and the aggregate properties of multiple systems in a given population can provide insight into the genesis of that population . multiples are of particular importance in the study of very low mass ( vlm ; m 0.1m ) stars and brown dwarfs . several of the first brown dwarfs identified were found as companions to nearby stars , and binaries composed entirely of vlm dwarfs are now known ( * ? ? ? * and references therein ) . the salient properties of these systems their small separations , high mass ratios and low frequency have been used as empirical tests of brown dwarf formation theories . astrometric monitoring of resolved doubles have provided direct measures of mass for a few vlm binaries , while the recently identified eclipsing binary 2mass j0535218 - 054608ab has enabled the first radius measurement in the substellar regime . coupled with independent age determinations , these observations also constrain brown dwarf evolutionary theories . multiplicity provides explanations for other observed phenomena , such as peculiar features in individual brown dwarf spectra and unusual photometric trends across the transition between l - type and t - type brown dwarfs . despite their fecundity , only a limited number of vlm binaries have resolved spectroscopic measurements . such observations provide detailed information on the components of these systems , and can clarify empirical trends as a function of spectral type , temperature or mass by eliminating the variables of age and composit

We present a new study of the mass distribution of very low mass ( vlm ) stars and brown dwarfs. This study is based on a combination of astrometric observations of resolved binary spectroscopic measurements of the stellar masses and a spectral type, temperature and mass. The results are presented in terms of the spectroscopy of j0535218 - 054608ab, which provides direct measurements of mass for a few vLm binaries, and the recently identified eclipsing binary 2.

we report the discovery of the wide l1.5+l4.5 binary 2mass j15200224 - 4422419ab , identified during spectroscopic followup of high proper motion sources selected from the two micron all sky survey . this source was independently identified by kendall et al . in the supercosmos sky survey . resolved photometry and low resolution near - infrared spectroscopy demonstrate that this system is composed of two well - separated ( 1 ) l dwarfs . component classifications are derived using both spectral


We investigate the classical eigenvalue problem that arises in hydrodynamics and is referred to as...

linear water - wave theory is a widely - used approach that allows to determine the frequencies and modes of free oscillations of a liquid in a container . such oscillations exist provided the liquid s upper surface is free and , in the framework of this theory , one obtains their frequencies and modes from a mixed steklov problem . the latter involves a spectral parameter in the boundary condition on the free surface . this boundary value problem ( usually referred to as the sloshing problem ) has been the subject of a great number of studies over 250 years ( see for a historical review and , , , , , for some of recent literature ) . it is also worth pointing out here that other steklov type eigenvalue problems have attracted considerable attention in last years . for some of these developments , see e.g. , , , . recently , the question of the so - called ` high spots ' defined by sloshing eigenfunctions corresponding to the fundamental eigenvalue attracted the authors attention . this question is not only similar , but closely related to the long - standing ` hot spots ' conjecture of j. rauch . ( it is worth mentioning that a substantial progress has been achieved in studies of this conjecture for the neumann laplacian during the past decade ; see , for example , the works , , , , . ) roughly speaking , the question about high spots concerns monotonicity properties of fundamental sloshing eigenfunctions ( see subsection 1.3 for a detailed description ) . several results about the location of high spots were proved in and . one of them deals with the fundamental eigenfunction ( it is unique up to a non - zero factor ) of the two - dimensional sloshing problem in the case when the domain s top interval is the one - to - one orthogonal projection of the bottom . the other one treat fundamental eigenfunctions in troughs ( their cross - sections are subject to the same condition ) , and some vertical axisymmetric containers . moreover , it was shown in that for vertic

We study the sloshing problem in a two - dimensional container with a top interval of one orthogonal projection of the bottom. We find that the eigenfunction is unique up to a non - zero factor, and that the top interval is a constant. The corresponding eenfunction is defined by the spectral parameter in the boundary condition on the free surface.

we investigate the classical eigenvalue problem that arises in hydrodynamics and is referred to as the sloshing problem . it describes free liquid oscillations in a liquid container . we study the case when is an axially symmetric , convex , bounded domain satisfying the john condition . the cartesian coordinates are chosen so that the mean free surface of the liquid lies in -plane and -axis is directed upwards ( -axis is the axis of symmetry ) . our first result states that the fundamental eige


Essential to the description of a quantum system are its local degrees of freedom , which enable...

quantum systems are usually described by a hilbert space , a state vector , and a hamiltonian . do these structures alone fully characterize a physical system ? without specifying more information , like a preferred choice of basis , it is difficult to make sense of the hamiltonian or the state . for example , consider the one - dimensional ising model , with hamiltonian the hamiltonian clearly describes a chain of locally coupled two - level systems . this interpretation is possible because the expression for the hamiltonian implicitly includes a partition of the total hilbert space into subsystems using a tensor product factorization , this choice of tensor product structure " ( tps ) allows one to write the hamiltonian simply in terms of local operators . however , if one does not specify a tps but instead writes the hamiltonian as a large matrix in some arbitrary basis , the system becomes difficult to interpret . is it the one - dimensional ising model , or is it a collection of interacting particles in three dimensions ? up to a change of basis , different hamiltonians are only distinguished by their energy spectra . moreover , the only canonical choice of basis is the energy eigenbasis . thus the hamiltonian and state vector alone do not yield an obvious physical description , at least without a choice of tps . we therefore ask , without a preferred choice of basis , is there a natural way to decompose the hilbert space into subsystems ( i.e. tensor factors ) , knowing only the hamiltonian ? in other words , do the energy eigenspaces and spectrum alone determine a natural choice of tps ? this is a question that has rarely been addressed in the literature , though it is discussed in a few papers such as . more commonly , it has been assumed that a preferred tps must be specified before any further progress can be made in describing the system . to even attempt finding a natural tps , one must first specify what constitutes a natural choice . here , we seek a c

We consider a quantum system with a hamiltonian and a state vector. The hamiltonians are only distinguished by their energy spectra. This is a natural way to decompose the hilbert space into subsystems ( i. E. Tensor factors ), knowing only the ten - product structure. In other words, do the energy eigenspaces and spectrum alone determine a Natural choice of ten.

essential to the description of a quantum system are its local degrees of freedom , which enable the interpretation of subsystems and dynamics in the hilbert space . while a choice of local tensor factorization of the hilbert space is often implicit in the writing of a hamiltonian or lagrangian , the identification of local tensor factors is not intrinsic to the hilbert space itself . instead , the only basis - invariant data of a hamiltonian is its spectrum , which does not manifestly determine


Gamma - ray burst ( grb ) afterglows are well described by synchrotron emission originating from...

in the fireball model , gamma - ray burst ( grb ) afterglows are thought to be the result of synchrotron radiation generated by electrons during the interaction of a strongly collimated relativistic jet from a compact source with its environment ( for recent reviews , see ) . initially the resulting spectra and light curves have been modelled using only the shock front of a spherical explosion and a simple power law approximation for the synchrotron radiation ( e.g. ) . one or more spectral and temporal breaks were used to connect regimes with different power law slopes . for the dynamics the self similar blandford - mckee ( bm ) approximation of a relativistic explosion was used . these models have been refined continuously . more details of the shock structure were included ( e.g. ) , more accurate formulae for the synchrotron radiation were used ( e.g. ) and efforts have been made to implement collimation using various analytical approximations to the jet structure and lateral spreading behavior ( see for an overview ) . on top of that , there have been studies focussing on arrival time effects ( e.g. ) and some numerical simulations ( e.g. ) . in this paper we introduce a code to reconstruct spectra and light curves from amrvac , a high performance relativistic hydrodynamics code . we verify our method by applying it to the analytically well understood bm solution . because different authors have recently started using the circumstellar density structure as a fitting parameter when fitting the bm solution to afterglow data , we generalize existing scaling coefficient prescriptions from the literature from insterstellar medium ( ism , for which the inverse radial slope of the density distribution is zero ) and stellar wind ( ) to general . _ these scaling coefficients are tabulated in the appendix and can be directly used when fitting to afterglow data_. we finish this part of the paper by comparing fit results to grb 970508 using our prescription to those of oth

We present a code to reconstruct spectra and light curves from amrvac, a high performance relativistic hydrodynamics code. The code is based on an analytically well understood blandford - mckee ( bm ) approximation of a relativistic explosion. We use this method to fit the bM solution to grb 970508 using our prescription to those of oth.

gamma - ray burst ( grb ) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the grb progenitor . we introduce a code to reconstruct spectra and light curves from arbitrary fluid configurations , making it especially suited to study the effects of fluid flows beyond those that can be described using analytical approximations . as a check and first application of our code we use it to fit the


One of the key features of small - worlds is the ability to route messages with few hops only using...

in a prescient 1929 novel called _ lncszemek _ ( in english , _ chains _ ) , karinthy imagines that any two people can be connected by a small chain of personal links , using no more than _ five _ intermediaries . years later , milgram validates the concept by conducting real - life experiments . he asks volunteers to transmit a letter to an acquaintance with the objective to reach a target destination across the united states . while not all messages arrive , successful attempts reach destination after six hops in average , popularizing the notion of _ six degrees of separation_. yet , for a long time , no theoretical model could explain why and how this kind of _ small - world _ routing works . one of the first and most famous attempts to provide such a model is due to jon kleinberg . he proposes to abstract the social network by a grid augmented with _ shortcuts_. if the shortcuts follow a heavy tail distribution with a specific exponent , then a simple greedy routing can reach any destination in a short time ( hops ) . on the other hand , if the exponent is wrong , then the time to reach destination becomes for some . this seminal work has led to multiple studies from both the theoretical and empirical social systems communities . in this paper , we propose a new way to numerically benchmark the greedy routing algorithm in the original model introduced by kleinberg . our approach uses dynamic rejection sampling , which gives a substantial speed improvement compared to previous attempts , without making any concession about the assumptions made in the original model , which is kept untouched . fueled by the capacity to obtain quick and accurate results even for very large grids , we give a fresh look on kleinberg s grid , through three independent small studies . first , we show that the model is in practice more robust than expected : for grids of given size there is quite a large range of exponents that grant short routing paths . then we observe that the lower

We present a new way to benchmark the greedy routing algorithm in kleinberg s model. We use dynamic rejection sampling to obtain a substantial speed improvement compared to previous attempts, without making any concession about the assumptions made in the original model, which is kept untouched. First, we show that the model is in practice more robust than expected: for grids of given size there is quite a large range of exponents that grant short routing paths. Then we observe that the lower the number of expositions, the faster the algorithm can be implemented.

one of the key features of small - worlds is the ability to route messages with few hops only using local knowledge of the topology . in 2000 , kleinberg proposed a model based on an augmented grid that asymptotically exhibits such property . in this paper , we propose to revisit the original model from a simulation - based perspective . our approach is fueled by a new algorithm that uses dynamic rejection sampling to draw augmenting links . the speed gain offered by the algorithm enables a deta


We present a gauge mediated supersymmetry breaking model having weak su(2 ) triplet , color su(3 )...

following the latest combination of mass and signal strengths of the higgs boson by the atlas and cms collaborations of the large hadron collider ( lhc ) , the particle spectrum of the standard model ( sm ) is complete and it reigns supreme as an effective theory for weak scale physics . however , in spite of its astonishing success , the anomalous magnetic moment of the muon , namely , remains an enigma . when compared to the sm estimate , the latest experimental result stands as the deviation is above level ( see also ) , and it can be resolved if we invoke new physics at a scale gev , which follows from , where is a coupling relevant to the new physics . in the minimal supersymmetric standard model ( mssm ) , a resolution of this deviation requires light superparticles , namely the smuons and chargino / neutralinos of gev , which propagate in the loop . with , the size of can be as large as . on the other hand , the observed higgs boson mass , gev , demands rather large radiative corrections , which are enhanced by heavy stops weighing tev or substantial left - right mixing . gauge mediated supersymmetry breaking ( gmsb ) models start with an advantage in this context that at the supersymmetry breaking scale itself the squarks / guino are heavier than sleptons / gauginos , i.e. the splitting is in the right direction . however , in minimal conventional gmsb , which employs a and a of as messengers , the heavy stop pulls up the slepton and weak gaugino soft masses to several hundred gev to a tev which are too high to explain the muon . in a previous paper ( see also ) , we proposed a gmsb model that naturally yielded light uncolored and heavy colored superpartners . to accomplish this , we employed weak su(2 ) triplet and color su(3 ) octet messenger multiplets instead of using the conventional su(5 ) 5-plets . even with these incomplete su(5 ) multiplets , gauge couplings still unify , though at the string scale gev which is somewhat higher than the grand unifica

We present a new model for gauge mediated supersymmetry breaking ( gmsb ) that naturally yields light uncolored and heavy colored superpartners. The model is based on a weak su(2 ) triplet and color su(3 ) octet messenger multiplet, which are used to produce light colored and heavy gaugino soft masses. We show that this model can be applied to any scale of gev, and it is able to reproduce the observed higgs boson mass, gev and its anomalous.

we present a gauge mediated supersymmetry breaking model having weak su(2 ) triplet , color su(3 ) octet and su(5 ) 5-plet messengers , that can simultaneously explain the muon data within 1 and the observed higgs boson mass of 125 gev . gauge coupling unification is nontrivially maintained . most of the parameter space satisfying both is accessible to the 14 tev lhc . the lighter of the two staus weighs around ( 100 - 200 ) gev , which can be a potential target of the ilc . sinp / tnp/2013/14 ,


The very fast inversion of the stokes vector ( vfisv ) is a milne - eddington spectral line...

the very fast inversion of the stokes vector ( vfisv ; * ? ? ? * ) is a spectral line inversion code tailored and optimized to invert the full disk spectro - polarimetric data of the _ helioseismic and magnetic imager _ ( hmi ) instrument on board the _ solar dynamics observatory _ ( sdo ; * ? ? ? hmi is a filtergram - type instrument that observes ( with one camera ) the stokes _ i _ , _ q _ , _ u _ , and _ v _ at six wavelength positions across the fe i 6173 spectral line for the full disk of the sun with 16 million pixels ( 4096 ccd ) every 135 s. all of the data pipeline procedures , and the spectral line inversion code in particular , have limited allowable runtimes in order to keep pace with the data flow rate and prevent a processing backlog . in the forward problem , vfisv solves the radiative transfer equation ( rte ) for polarized light using the milne - eddington ( me ) approximation to generate a set of stokes profiles from a given model atmosphere . the me approximation assumes that all the parameters describing the atmosphere are constant along the line of sight ( los ) except for the source function , which varies linearly with optical depth . in addition , the generation of polarized radiation is formulated in the classical zeeman effect regime . traditionally , me models applied to polarized rte problems use up to eleven free parameters to describe the atmosphere in which the stokes profiles are generated . there are five thermodynamical parameters : the line - to - continuum absorption ratio , , the doppler width , , the damping parameter of the voigt function , , and the components of the linearized source function , and , respectively . the magnetic field vector is described by three variables , _ i.e. _ the magnetic field strength , , its inclination with respect to the los , , and its azimuth in the plane perpendicular to the line of sight , ( which is referenced to a column of pixels on the hmi ccd and increases counter - clockwise ) . there a

We present a new method for inverting the stokes vector ( vfisv ) data from the _ helioseismic and magnetic imager _ ( hmi ) instrument on board the solar dynamics observatory _. The method is based on the milne - eddington approximation to generate a set of stok profiles from a given model atmosphere. The spectral line inversion code is optimized to invert the full disk spectro - Polarimetric data of the.

the very fast inversion of the stokes vector ( vfisv ) is a milne - eddington spectral line inversion code used to determine the magnetic and thermodynamic parameters of the solar photosphere from observations of the stokes vector in the 6173 fe i line by the _ helioseismic and magnetic imager _ ( hmi ) onboard the _ solar dynamics observatory _ ( sdo ) . we report on the modifications made to the original vfisv inversion code in order to optimize its operation within the hmi data pipeline and p


The aim of this work is to understand the influence of chaotic states in control problems involving...

controlling quantum phenomena in atomic and molecular systems is an active area of research today . persistent theoretical and experimental efforts have led to the formulation of several ingenious control schemes for both atomic and molecular systems . recently researchers have been interested in determining the control landscape " for specific systems . the motivation for undertaking such extensive studies is atleast twofold . firstly , several optimal control efforts seem to succeed despite employing local search algorithms in a prohibitively high dimensional control parameter space . rabitz and coworkers reason that the topology of the control landscape can shed light on the robustness of the control strategies . secondly , many control schemes involve few , carefully chosen , levels which provide valuable insights into the control process . however , such few - level schemes might be compromised due to several reasons and one hopes that identifying the features of the control landscape associated with the deviations might lead to better control techniques . in order to set the stage for our work we briefly discuss the concept of a control landscape . consider a hamiltonian of the form with being the dipole operator and being the control field . there are two perspectives on the control problem which are of interest to the present work . the first one involves using a given field characterized by one or more control variables . the objective in this case is to study the variation of , say , the transition probability between an initial state and a final state at some target time . the control landscape is constructed by viewing the transition probability as a functional of the field parameters _ i.e. , _ $ ] . regions on the landscape with high values for yield the best possible choice of the control variables in the presupposed . note that it is quite possible to have several distinct choices for the control variables which yield the same value for . several suc

We consider a hamiltonian of the form with being the dipole operator and being the control field. The first approach is to study the variation of the transition probability between an initial state and a final state at some target time. In this case, the control landscape is constructed by viewing the transition probabilities as a functional of the field parameters. We find that the control Landscape can be obtained from the following two approaches: the first one involves using a given field characterized by one or more control variables.

the aim of this work is to understand the influence of chaotic states in control problems involving strong fields . towards this end , we numerically construct and study the strong field control landscape of a bichromatically driven double well . a novel measure based on correlating the overlap intensities between floquet states and an initial phase space coherent state with the parametric motion of the quasienergies is used to construct and interpret the landscape features . walls " of no contr


By a numerical continuation method called a diagonal homotopy we can compute the intersection of...

homotopy continuation methods provide reliable and efficient numerical algorithms to compute accurate approximations to all isolated solutions of polynomial systems , see e.g. for a recent survey . as proposed in , we can approximate a positive dimensional solution set of a polynomial system by isolated solutions , which are obtained as intersection points of the set with a generic linear space of complementary dimension . new homotopy algorithms have been developed in a series of papers to give numerical representations of positive dimensional solution sets of polynomial systems . these homotopies are the main numerical algorithms in a young field we call _ numerical algebraic geometry_. see for a detailed treatment of this subject . this paper provides an algorithm to compute numerical approximations to positive dimensional solution sets of polynomial systems by introducing the equations one at a time . the advantage of working in this manner is that the special properties of individual equations are revealed early in the process , thus reducing the computational cost of later stages . consequently , although the new algorithm has more stages of computation than earlier approaches , the amount of work in each stage can be considerably less , producing a net savings in computing time . this paper is organized in three parts . first we explain our method to represent and to compute a numerical irreducible decomposition of the solution set of a polynomial system . in the third section , new diagonal homotopy algorithms will be applied to solve systems subsystem by subsystem or equation by equation . computational experiments are given in the fourth section . we start this section with a motivating illustrative example , which shows the occurrence of several solution sets , of different dimensions and degrees . secondly , we define the notion of witness sets , which we developed to represent pure dimensional solution sets of polynomial systems _ numerically_. witness

We present a new algorithm to compute numerical approximations to the solution set of a polynomial system by introducing the equations one at a time. This algorithm is based on the homotopy continuation method, which provides an efficient and reliable numerical algorithm to calculate accurate approximates to all isolated solutions of polynomisms. It is shown that the algorithm can be applied to solve systems subsystem by subsystem or equation by equation.

by a numerical continuation method called a diagonal homotopy we can compute the intersection of two positive dimensional solution sets of polynomial systems . this paper proposes to use this diagonal homotopy as the key step in a procedure to intersect general solution sets . of particular interest is the special case where one of the sets is defined by a single polynomial equation . this leads to an algorithm for finding a numerical representation of the solution set of a system of polynomial


the `` twisted '' black holes recently proposed by zhang , and further considered by chen and jing , and by ong , are certainly ricci - flat , and so mathematically satisfy the vacuum einstein equations . however , these `` twisted '' black holes are merely minor variants on the well - known taub nut spacetimes . in particular , since these `` twisted '' black holes do not fall into the standard kerr newman class , they certainly violate the _ spirit _ of the black hole uniqueness theorems . therefore , even without doing any specific calculation , it is clear that there must be something odd / unusual about these `` twisted '' black holes , something that violates the input assumptions going into the black hole uniqueness theorems , and that this something odd / unusual is likely to render these `` twisted '' black holes unphysical in any realistic astrophysical setting . in the interests of clarity we shall perform a brief elementary analysis of some of the key features of these `` twisted '' black holes , somewhat along the lines of for the kerr geometry , relating these `` twisted '' black holes to the more usual taub nut discussion . specifically , we shall demonstrate that : * these `` twisted '' black holes are not globally asymptotically flat . * these `` twisted '' black holes actually connect two universes via a timelike wormhole . * these `` twisted '' black holes are causally diseased : the entire domain of outer communication is `` totally vicious '' . ( meaning the entire region _ outside _ the event horizon is infested with closed timelike curves . ) to verify these assertions it is sufficient to look at the massless case , the physically problematic issues persist and if anything are actually worse in the massive case . consider the spacetime geometry this manifold is ricci - flat , , so that it satisfies the vacuum einstein equations , and is not riemann - flat , , ( so it really is a curved spacetime ) . in particular the quadratic curvature invari

We present a brief analysis of the key features of these ' twisted '' black holes, and show that they are not globally asymptotically flat. In particular, we demonstrate that these _ twisted_'' Black holes are causally diseased: the entire domain of outer communication is a totally vicious wormhole.

+ so - called `` twisted '' black holes have recently been proposed by zhang ( 1609.09721 [ gr - qc ] ) , and further considered by chen and jing ( 1610.00886 [ gr - qc ] ) , and more recently by ong ( 1610.05757 [ gr - qc ] ) . while these spacetimes are certainly ricci - flat , and so mathematically satisfy the vacuum einstein equations , they are also merely minor variants on taub nut spacetimes . consequently they exhibit several unphysical features that make them quite unreasonable as reali


We have investigated the effects of either distorting hydrogen bonds or removing proton degeneracy...

network - forming liquids such as water are ubiquitous in nature . they differ from normal liquids by the presence of directional intermolecular interactions that result in the formation of bonds . these directional attractive forces favor the formation of structured regions that , due to the orientational constraints on the bonded molecules , have lower density than unbonded regions . as a result , a density anomaly , consisting in the expanion under isobaric cooling of these systems , appears . this density anomaly has been related to a phase transition between a low - density liquid ( ldl ) and a high - density liquid ( hdl ) . experiments and simulations of water predict a hdl - ldl first - order phase transition in an experimentally inacessible region of the phase diagram . but water is not an isolated case , computer simulations of realistic models for carbon , phosphorus , , and si suggest the existence first - order ldl - hdl phase transitions in these materials . the presence of a number of solid phases in water , as well as of solid - solid first - order phase transitions , have suggested the possibility that systems with solid polymorphism exhibit several liquid phases with local structures similar to the ones present in the crystal phases . this assumption was confirmed for a number polymorfic liquids such as se , s , bi , p , , sn , sb , , and . in all these cases , a full understanding of the effects of the number , spatial orientation and strength of the bonds is still missing . in order to shed some light onto this problem , recently a simple approach representing hydrogen bonds through ice variables has been proposed . the zero temperature ice model was succesful in giving the description of ice entropy , for dense systems but an order - disorder transition for finite temperatures is absent . recently a description based also on ice variables but which allows for a low density ordered structure was proposed . the associating lattice gas model ( alg)

We present a new approach to the associating lattice gas model ( alg ) for hydrogen bonds in water. This approach is based on the asassociationing lattique gas model and allows for a low density ordered structure. The model is characterized by a first - order phase transition between a high - density liquid ( ldl ) and a lower - density liquid (hdl). We show that the model can be used to describe the diffusion of hydrogen bonds through ice variables.

we have investigated the effects of either distorting hydrogen bonds or removing proton degeneracy on the thermodynamic properties of a minimal model for associating liquids . the presence of two liquid phases and a density anomaly is unaffected in both cases . increasing the degeneracy of bonded structures leads to lower temperature critical points and a steeper liquid - liquid coexistence line , implying a low density liquid of larger entropy . analysis of the hydrogen bond net accross the pha


The 1 - 2 model on the hexagonal lattice is a model of statistical mechanics in which each vertex...

the 1 - 2 model on the hexagonal lattice was introduced by schwartz and bruck as an intermediary in the calculation of the capacity of a constrained coding system . they expressed the capacity via holographic reductions ( see ) in terms of the number of perfect matchings ( or dimer configurations ) , and the latter may be studied via the pfaffian method of fisher , kasteleyn , and temperley . the 1 - 2 model may be viewed as a model of statistical mechanics of independent interest , and it is related to the ising model and the dimer model . in the current paper , we study the 1 - 2 model within this context , and we establish the exact form of the associated critical curve . a 1 - 2 configuration on the hexagonal lattice is a subset of edges such that every vertex is incident with either one or two edges of . there are three real parameters , which are associated with the three classes of edges of . the weight of a configuration on a finite region is the product over vertices of one of chosen according to the edge - configuration at . ( see figure [ fig : sign ] . ) through a sequence of transformations , the 1 - 2 model turns out to be linked to an enhanced ising model , a polygon model , and a dimer model . these connections are pursued here , and in the linked paper . the main result ( theorem [ thm : main ] ) states in effect that , when , the surface given by is critical . this is proved by an analysis of the behaviour of the two - edge correlation function as . the model is called _ uniform _ if , and thus the uniform model is not critical in the above sense . there has been major progress in recent years in the study of two - dimensional ising models via rhombic tilings and discrete holomorphic observables ( see , for example , ) . there is a rhombic representation of the critical polygon model associated with the 1 - 2 model , and an associated discrete holomorphic function , but this is not explored here . certain properties of the underlying hexagonal latt

We study the 1 - 2 model on the hexagonal lattice, and establish the exact form of the critical curve. The critical curvature is defined by a rhombic representation of the polygon model associated with the 1 2 model, a discrete holomorphic observable, an arbitrary rhomboid, or a non - rheomorphically symmetric observabilis.

the 1 - 2 model on the hexagonal lattice is a model of statistical mechanics in which each vertex is constrained to have degree either or . there are three edge - directions , and three corresponding parameters , , . it is proved that , when , the surface given by is critical . the proof hinges upon a representation of the partition function in terms of that of a certain dimer model . this dimer model may be studied via the pfaffian representation of fisher , kasteleyn , and temperley . it is pr


X - ray studies of nearby spiral galaxies with star formation allow us to investigate temperature...

it is now thirty years since the first unambiguous identification of x - ray emission from our nearest giant spiral , m31 ( margon , lampton & cruddace 1974 ) . today we know that x - ray emission in galaxies comes from discrete sources and hot diffuse gas . discrete sources ( accreting compact objects and supernova remnants ) are a fossil record of the stellar population , and may be used as a probe of star formation history . diffuse x - ray emission is the tracer of the hot gas ( k ) in galaxies and clusters ; in galaxies , it is an indicator of recent star formation . disentangling truly diffuse gas from faint , unresolved sources such as faint x - ray binaries ( xrbs ) , cataclysmic variables , coronal emission from main - sequence and t tauri stars is still a major problem , despite the fact that sensitivity and spatial resolution of the x - ray detectors have improved by three orders of magnitude since those early observations . today , x - ray studies of nearby galaxies can be conducted on two complementary levels . we can do a statistical study of the spatial and spectral distribution of the sources : this can help us distinguish between different physical classes of x - ray emitters . and we can use the x - ray sources as a tool to probe the structure and evolution of the host galaxy . statistical studies of x - ray sources in the milky way are hampered by the large relative uncertainty in the distance of most sources ( often by a factor of two ) and by our very incomplete view due to the large extinction in the galactic plane . population studies can be conducted more easily in nearby galaxies , with more favorable viewing angles and the same relative distance for all the sources . by studying a large sample of galaxies it is also possible to quantify how the x - ray properties of a galaxy depend on its structural type and level of star - forming activity . moreover , by quantifying the relation between observed x - ray properties and star formation histo

We present a statistical study of the spatial and spectral distribution of the sources in nearby galaxies. This can help us distinguish between different physical classes of x - ray emitters, and to use them as a tool to probe the structure and evolution of the host galaxy.

x - ray studies of nearby spiral galaxies with star formation allow us to investigate temperature and spatial distribution of the hot diffuse plasma , and to carry out individual and statistical studies of different classes of discrete sources ( low- and high - mass x - ray binaries , supernova remnants , supersoft and ultra - luminous sources ) . in particular , we briefly review the different models proposed to explain the ultra - luminous sources . we can then use the x - ray properties of a


An estimate of the one - loop correction to the power spectrum of the primordial curvature...

for some years , the theory of inflation has represented our most successful approach to the very early universe . although we do not know with certainty what physical conditions applied in the very distant past , it is believed that a number of fundamental properties of our universe were determined at that time . among the most important of these is the ensemble of small density perturbations which later condensed into galaxies and gave rise to the network of cosmic structure we see today . therefore , one question which must be answered by any theory which purports to describe the very early universe concerns the origin and nature of these perturbations . in inflationary models , the answer is provided by use of an era of quasi - exponential expansion to generate small fluctuations from the vacuum . remarkably , the properties of these perturbations can be calculated by applying a minimal extension of quantum field theory to the expanding universe . the inflationary perturbations are generated by quantum - mechanical effects among field modes of wavelength around the time when such modes are of order the hubble scale , that is , . if the inflationary expansion is still ongoing when these perturbations are generated then the local hubble scale continues to contract , so that eventually they are far outside the horizon , giving . in this regime the field behaves in an approximately classical fashion . therefore the evolution of the curvature perturbation can be calculated reliably until the end of inflation , when it is generally assumed to settle down to a time - independent final value , unless isocurvature modes exist which drive its evolution on large scales . in this simple picture we have a robust prediction of the properties of the perturbations regardless of the details of the inflationary era . the above account neglects at least one possible source of trouble , namely the question of quantum mechanical corrections . in any quantum theory , including inflat

We present a simple model for the evolution of the inflationary perturbations in the expanding universe. The model is based on an era of quasi - exponential expansion to generate small fluctuations from the vacuum. This model is used to calculate the properties of the perturbations, which are generated by quantum mechanical effects. We show that the evolution is robust until the end of inflation, when it is generally assumed to settle down to a time - independent final value.

an estimate of the one - loop correction to the power spectrum of the primordial curvature perturbation is given , assuming it is generated during a phase of single - field , slow - roll inflation . the loop correction splits into two parts , which can be calculated separately : a purely quantum - mechanical contribution which is generated from the interference among quantized field modes around the time when they cross the horizon , and a classical contribution which comes from integrating the


Recent rate measurements of mesons and baryons produced in tev proton - antiproton and electron -...

heavier -flavoured hadrons represent a fecund source of particle physics . while the rich interplay between electroweak and non - perturbative strong effects typically poses formidable experimental and theoretical challenges , decays of hadrons with masses at the frontiers of standard model spectroscopy constitute an exciting proving ground for effective theories , qcd factorization and lattice methods , as well as potential models . moreover , such heavy hadronic states present opportunities to uncover real or constrain hypothetical new physics lying beyond the standard model . the measurement of observables from baryons and strange or charmed mesons is complementary to the wealth of physics that the babar , belle , and cleo collaborations have harvested from colliders operating at the open - beauty threshold . comparisons of heavy -hadron decays to the analogous non - strange ( ) decays can yield advantages that include cancellations of hadronic uncertainties , tests of flavour symmetry , decay - amplitude disentanglement , and improved access to fundamental electroweak parameters of nature . this paper reviews recent rate measurements of mesons and baryons produced in tev proton - antiproton and electron - positron collisions at the fermilab tevatron ( usa ) and kekb ( japan ) accelerator facilities , respectively . described are first observations of and decays by cdf ; recent results on decays and worldwide status from belle , cdf , and ; the first observation of 1 by ; the first observation of the mode and a search for decays by belle ; three recently updated measurements of charmless two - body meson decays by cdf ; and first observations of and decays by cdf . the cabibbo - suppressed mode , as indicated in fig . [ fig : bsdsk_diagrams ] , has contributions from both upper- and lower - vertex charm such that the same parent state can decay both to and final states , as distinct from the analogous mode . due to the fact that these decay amplitudes can interfe

We review recent rate measurements of mesons and baryons produced in tev proton - antiproton and electron - positron collisions at the fermilab tevatron ( usa ) and kekb ( japan ) accelerator facilities. We compare these rates to previous measurements of charmless two - body meson decays by cdf, belle, and; the first observation of 1 by; and the first observations of and decays from belle; three recently updated measurements of and, respectively, of.

recent rate measurements of mesons and baryons produced in tev proton - antiproton and electron - positron collisions are reviewed , including the first observations of six new decay modes : ( cdf ) , ( cdf ) , 1 ( ) , ( belle ) , ( cdf ) , and ( cdf ) . also examined are branching - fraction measurements or limits for the modes ( belle , cdf , and ) , the radiative penguin decay ( belle ) , and three two - body charmless meson decay channels ( cdf ) . implications for the phenomenology of elect


It is widely accepted that topological quantities are useful to describe quantum liquids in low...

-0.3 cm topological quantities are fundamental to describe low dimensional quantum liquids where standard symmetry breaking do not have a primal importance . typical examples are quantum hall liquids and anisotropic superconductors with time - reversal symmetry breaking . recently spin hall conductance for semiconductors are also attracting much current interest . the ( spin ) hall conductance has a characteristic geometrical meaning . in some physical units , they are given by the first chern number of the berry connection . in practical numerical calculations , we diagonalize hamiltonians on a set of discrete points on the brillouin zone ( bz ) . it is thus crucial to develop an efficient method of revealing the topological property of infinite systems with continuum bz from corresponding finite systems with discrete bz . we propose an efficient method for the calculation of the chern numbers on a discretized bz based on a geometrical formulation of topological charges in lattice gauge theory . the chern numbers thus obtained are _ manifestly gauge - invariant _ and _ integer - valued _ even for a discretized bz . one can compute the chern numbers using wave functions in _ any gauge _ or _ without specifying gauge fixing - conditions_. details of the formulation and the basic results were published elsewhere . -0.3 cm : let us consider chern numbers in the quantum hall effect as a typical example . the spin hall conductances is treated similarly . we take the bz by ( , 2 with integers ) . since the hamiltonian is periodic in both and directions , the bz is regarded as a two - dimensional torus . when the fermi energy lies in a gap , the hall conductance is given by , where denotes the chern number of the th bloch band , and the sum over is restricted to the bands below the fermi energy . the chern number assigned to the th band is defined by with , where the berry connection with is defined by a normalized wave function of the th bloch band satisfying and . the ch

We present a method for the calculation of the spin hall conductances on discrete points on the brillouin zone ( bz ). The chern numbers are given by the first cheron number of the berry connection. In this paper, we consider the quantum hall effect as a typical example.

it is widely accepted that topological quantities are useful to describe quantum liquids in low dimensions . the ( spin ) hall conductances are typical examples . they are expressed by the chern numbers , which are topological invariants given by the berry connections of the ground states . we present a topological description for the ( spin ) hall conductances on a discretized brillouin zone . at the same time , it is quite efficient in practical numerical calculations for concrete models . we


Relative abundances of the five stable isotopes of titanium ( ti to ti ) are measured for 11 m...

insights into the chemical evolution of the galaxy are provided by the relative abundances of elements in stars belonging to the main populations of the galaxy : halo , disk ( thick and thin ) , and bulge . in a common representation of abundances , one plots [ x / fe ] versus [ fe / h ] for the element x and fe . = (a / b)(a / b) and (nn where is the number density . ] elements may be grouped into classes with each element in a class exhibiting a similar behavior . comprising one such class are the -elements : the elements in this class include mg , si , s and ca , each with its most abundant isotope having a mass number that is a multiple of four . observations show that the runs of [ x / fe ] for each of the -elements are similar for stars of a given population presently in the solar neighborhood . the value of [ x / fe ] is positive and constant ( say , dex ) for [ fe / h ] but decreases to the solar value ( i.e. , [ x / fe ] ) as thin disk stars are sampled at [ fe / h ] . the change in the variation of [ x / fe ] versus [ fe / h ] for -elements at [ fe / h ] is widely attributed to the onset of contamination of interstellar gas with the fe - rich -poor ejecta from type ia supernovae that reduces the [ /fe ] previously established by -rich fe - poor ejecta from type ii supernovae . theoretical modeling of galactic chemical evolution ( gce ) reproduces quite well the [ /fe ] versus [ fe / h ] trends for the standard elements - see , for example , timmes , woosley , & weaver ( 1995 , hereafter , tww95 ) , goswami & prantzos ( 2000 , hereafter , gp00 ) , and kobayashi et al . ( 2006 , hereafter , k06 ) . such modeling enterprises , however , ignore the observational differences between the runs of [ x / fe ] versus [ fe / h ] for thin and thick disk stars . titanium with its principal isotope being ti would appear to qualify as an element . indeed , the observed run of [ ti / fe ] with [ fe / h ] is similar to that of a standard -element . yet , gce models fail to

We present a new model of galactic chemical evolution ( gce ) that reproduces the [ x / fe ] versus [ f /.

relative abundances of the five stable isotopes of titanium ( ti to ti ) are measured for 11 m dwarfs belonging to the thin disk ( four stars ) , thick disk ( three stars ) , the halo ( one star ) , and either the thick or the thin disk ( three stars ) . over the metallicity range of the sample ( [fe / h] ) , the isotopic ratios are approximately constant to the solar system ratios . there is no discernible difference between the isotopic ratios for thin and thick disk stars . isotopic ratios ar


We propose the realization of linear crystals of cold ions which contain different atomic species...

current ion trapping technology has led to rapid progress toward the realization of elementary quantum processors . the ability to control the motional and internal states of the trapped ions with high accuracy allows for the experimental implementation of several textbook models such as quantum simulations of a dirac equation with the zitterbewegung and the klein paradox . on the other hand , the internal states of laser - cooled and trapped ions represent effective spins , which can be made to interact with each other for performing magnetic quantum phase simulations . these interactions may be realized by applying magnetic field gradients or by laser light fields . in both cases , spin- ion crystals allow for a detailed investigation of complex quantum phase transitions and magnetic frustrated effects . preliminary experimental steps in ion crystals have been realized with interacting spins of two mg and three yb ions in a linear configuration . because of the long - range spin - spin interactions , the larger collections of trapped ions are expected to lead to intriguing , and so far unobserved phenomena , such as the formation of super - solids or exotic quantum phases , where the specific advantages of the ion crystal are : almost perfect state preparation and readout with single site addressability , long coherence times , and a full tunability of the spin - spin interactions , even for long ranges beyond next - neighbor couplings . going beyond spin- systems and trapping different ion species with spin will allow the study of novel aspects of quantum magnetism in a mixed spin chains . such impurity doped systems might model effects which are of interest in solid state physics . our proposal is inspired by the outstanding progress in quantum logic spectroscopy , where a single clock ion and a single readout ion are simultaneously confined and coupled through the mutual coulomb repulsion , such that one can transfer the clock ion electronic state to the readou

We present a new method for the study of quantum magnetism in a mixed spin chain with two clock ion and one readout ioon. This method is inspired by the outstanding progress in quantum logic spectroscopy, where a single clock ions and a readout electron are simultaneously confined and coupled through the mutual coulomb repulsion, such that one can transfer the clock - ionic electronic state to the readou. The proposed method is based on the experimental results of the irc - doped spher.

we propose the realization of linear crystals of cold ions which contain different atomic species for investigating quantum phase transitions and frustration effects in spin system beyond the commonly discussed case of . mutual spin - spin interactions between ions can be tailored via the zeeman effect by applying oscillating magnetic fields with strong gradients . further , collective vibrational modes in the mixed ion crystal can be used to enhance and to vary the strength of spin - spin inter


We consider one of the quantum key distribution protocols recently introduced in ref

recently , we have shown how two - way quantum communication can profitably be exploited to enhance the security of continuous variable quantum key distribution . in particular , we have investigated the security of two - way protocols in the presence of collective gaussian attacks which are modelled by combinations of entangling cloners . even though this situation is the most important one from the point view of the practical implementation , the effect of other kind of gaussian attacks ( i.e. , not referable to entangling cloners ) must also be analyzed . in this paper , we study the security of the two - way coherent - state protocol of ref . against individual attacks where an eavesdropper ( eve ) combines two different gaussian quantum cloning machines ( also called _ gaussian cloners _ ) . in particular , we are able to show the robustness of the two - way protocol when the first cloner is fixed to be symmetric in the output clones . this symmetry condition enables us to derive the results quite easily but clearly restricts our security analysis to a preliminary stage . for this reason , the _ optimal _ performance of gaussian cloners against two - way quantum cryptography is still unknown at the present stage . consider a stochastic variable with values distributed according to a gaussian probability \ , , \]]with variance . this variable is taken as input of a classical channel that outputs another stochastic variable with values . in particular , the classical channel is called _ additive gaussian channel _ if , for every input , the conditional output is gaussianly distributed around with some variance note . as a consequence , the output variable is a gaussian variable with zero mean and variance . according to shannon s theory , the classical correlations between the input and output variables lead to a mutual information where is the signal to noise ratio ( snr ) . this formula gives the maximal number of bits per gaussian value that can be sent throug

We study the security of two - way coherent - state protocol of ref. Against individual attacks where an eavesdropper ( eve ) combines two different gaussian quantum cloning machines ( also called _ gausian cloners _). In particular, we show that the first cloNER is fixed to be symmetric in the output clones. This symmetry condition enables us to derive the results quite easily but clearly restricts our security analysis to a preliminary stage.

we consider one of the quantum key distribution protocols recently introduced in ref . [ pirandola et al . , nature physics * 4 * , 726 ( 2008 ) ] . this protocol consists in a two - way quantum communication between alice and bob , where alice encodes secret information via a random phase - space displacement of a coherent state . in particular , we study its security against a specific class of individual attacks which are based on combinations of gaussian quantum cloning machines .


Design and scientific investigation are recognized as key components of undergraduate physics...

there is currently widespread acceptance among the physics education research community as well as organizations concerned with preparing students for future jobs in stem fields that undergraduate laboratory curricula should have a strong focus on construction of knowledge and design of experiments to test models. many successful science curricula such as the investigative science learning environment ( isle ) , learning by design ( lbd ) , and scientific community labs ( scl ) have been developed with these as primary goals. etkina et al showed that isle students who designed their own experiments not only performed as well as other non - design isle students on traditional exams , but they also significantly outperformed the non - design group on experimental tasks that required application of scientific abilities to a new situation. a key component of curricula like isle and lbd is the implementation of an inquiry learning cycle and having the opportunity to practice that learning cycle many times . that is , students are provided with a framework that reflects scientific habits of mind. many examples of such frameworks can be found in the literature. while these learning cycles tend to focus on designing experiments to answer a particular question ( i.e. , what is the relationship between the period and length of a pendulum ? ) , another class of design which is perhaps more relevant to this study is what could be called _ engineering design_. that is , students design a device or system capable of achieving a certain goal ( i.e. , a circuit capable of turning on an led two seconds after a switch is thrown ) . the engineering is elementary ( eie ) curriculum has developed their own learning cycle for this kind of design. what all of the learning cycles have in common is that students develop a plan , execute the plan , compare results against expectations / desired results , then go back and refine the plan . the process continues until the students have answere

The engineering is elementary curriculum has developed their own learning cycle for designing a device or system capable of turning on an led two seconds after a switch is thrown. This cycle is based on the design of a circuit capable of achieving a certain goal ( i. E., a Circuit capable of Turning on an LED two seconds après a Switch is tossed ). The students develop a plan, execute the plan and compare results against expectations / desired results, then go back and refine the plan to improve the results.

design and scientific investigation are recognized as key components of undergraduate physics laboratory curricula . in light of this , many successful lab programs have been developed to train students to develop these abilities , and students in these programs have been shown to exhibit a higher transfer rate of scientific abilities to new situations . in this paper , i use data from an electronics class for physics majors to investigate how giving students the opportunity to design circuits b


I present a brief overview of the advantages of using a consistent effective lagrangian approach in...

in this talk i will discuss the possibilities of detecting non - physics thorough virtual effects at a high - energy linear collider . in the description of these effects i will use the effective lagrangian formalism . it is a commonly held belief that the standard model is but the low - energy limit of a more fundamental theory . in fact there is a myriad of models which reduce to the at low energies ( below , say , ) but which exhibit a plethora of new effects at smaller scales . i will adopt this paradigm with the added condition that there is a energy gap between the scale and the scale of new physics . one important goal of the approach i will follow ( for general references see and references therein ) is to obtain reliable estimates ( or reliable bounds ) for using current data ; this information can then be used to estimate the energy at which new colliders must operate . note that there are interesting models which do _ not _ satisfy . for example , many supersymmetric theories predict light , non- scalars of masses below . one can discuss such theories using the formalism to be developed below , but in order to do so the spectrum at low energies must be modified to include all the light supersymmetric particles . i will not consider this possibility here ( see ) . given the presence of a gap we can imagine integrating out all the heavy excitations of the theory . the effective interactions ( for the light particles ) generated in this manner are summarized in an effective lagrangian . schematically , denoting the heavy fields by , the light fields by , and the action for the theory underlying the by , then the effective action is \ ;  ( i s ) ]\ ] ] note that will have a dependence on , and that assumed much larger than any of the light physics scales ( including the energy at the available experiments ) . thus one can do an expansion in powers of ( up to possible logarithmic factors ) , where can be expanded as a linear combination of _ local _ operators

We discuss the possibility of detecting non - physics thorough virtual effects at a high - energy linear collider. In this talk i will discuss the possibilities of identifying non _ physics through virtuelle effects at low energies.

i present a brief overview of the advantages of using a consistent effective lagrangian approach in parameterizing virtual new physics effects . i then apply the formalism to certain top - quark processes . 6.5 in 16.7 cm by -2.2 cm by -2 cm by 1 in # 1^(#1 ) # 1su(#1 ) = ^^j # 1#2#3*#1 * , # 2 ( # 3 ) # 1#2#3*#1 * ( # 3 ) # 2 p 16 prd references 16 npb references #1#2#3astron . astrophys . # 1#2#3astron . astrophys . suppl . # 1#2#3amer . j. phys . # 1#2#3am . ny acad . sci . # 1#2#3ann . phys


In multi - object stochastic systems , the issue of sensor management is a theoretically and...

multi - target sensor control / management is essentially an optimal non - linear control problem . the goal of multi - target sensor management is to direct the right sensor on the right platform to the right target at the right time . however , the multi - target sensor control problem differs from the classical control problem in that it deals with highly complex multi - object stochastic systems . in multi - object stochastic systems , not only do the number of objects vary randomly in time , but the measurements are subject to missed detections and false alarms . this means that the multi - target state and multi - target observation are inherently finite - set - valued . consequently , standard optimal control techniques are not directly applicable . nonetheless , the multi - target sensor scheduling problem can still be cast in the framework of partially observed markov decision processes ( pomdps ) , where the states and observations are instead finite - set - valued , and control vectors are drawn from a set of admissible sensor actions based on the current information states , which are then judged against the values of an objective function associated with each action . a unified approach to characterizing systems with finite - set - valued states is the multi - object systems framework , where uncertainty is described by multi - object probability density functions , and formalized via point process theory , or equivalently by random finite set ( rfs ) theory through mahler s finite set statistics ( fisst ) . the key advantage of the rfs based approach is that of a principled framework for modelling , estimation and control of multi - object systems . in this paper , we formulate the sensor control problem as a pomdp with an information - theoretic objective function as well as finite - set - valued states and measurements . in essence , our approach can be summarized by three basic steps : 1 . modelling the sensor and targets as a multi - object stochas

We present a non - linear approach to the multi - target sensor control problem, which is essentially an optimal non - lineal control problem in multi _ object stochastic systems. The multi point process theory ( rfs ) is a framework for modelling and estimation of multi _ target _ sensors. It is based on a random finite set ( ) theory, where uncertainty is defined by multi.

in multi - object stochastic systems , the issue of sensor management is a theoretically and computationally challenging problem . in this paper , we present a novel random finite set ( rfs ) approach to the multi - target sensor management problem within the partially observed markov decision process ( pomdp ) framework . the multi - target state is modelled as a multi - bernoulli rfs , and the multi - bernoulli filter is used in conjunction with two different control objectives : maximizing th


In this paper , we studied the strategies to enhance synchronization on directed networks by...

synchronization is an important dynamical process in many systems . understanding and controlling this collective dynamics is of both theoretical and practical significance . many methods have been proposed to enhance the network synchronizability , including the redistribution of the coupling strengths , the modification of the network structure , the flipping of link directionality , and so on . each group of methods has its specific range of applications since different systems are under different technical constrains . as real systems are frequently manipulated by growing out new connections and eliminating redundant connections , we here focus on the link reconstructing method to enhance synchronizability . the word reconstructing " stands for manipulations including adding , removing and rewiring links , and in each manipulation only one link is created or changed . the reconstructing method for undirected networks has already been studied by using the information embedded in laplacian eigenvectors . however , the spectral method can not be directly applied to directed networks , since the complex value emerges in eigenvectors when the laplacian matrix is asymmetry . up to now , how reconstructing methods affect the synchronization on directed networks lacks of systematic consideration . previous works show that there are two important factors that mainly affect the synchronization on directed networks : the in - degree distribution and the hierarchical structure . generally speaking , the more homogeneous the in - degree distribution in a directed network is , the stronger the network synchronizability is . the synchronizability in directed networks can be approximately expressed by . a smaller indicates a better synchronizability . accordingly , to enhance synchronizability in directed networks , we can either decrease or increase which are respectively corresponding to removing the links that point to the nodes with maximum in - degree or adding links that

We study the link reconstructing method for directed networks. In this paper, we show that the in - degree distribution of the network is significantly affected by the number of links that point to the nodes with maximum in. We also discuss the effect of adding or removing links on the synchronizability of the networks, and show that it can be used to enhance the synchronousizabilité of the systems.

in this paper , we studied the strategies to enhance synchronization on directed networks by manipulating a fixed number of links . we proposed a centrality - based reconstructing ( cbr ) method , where the node centrality is measured by the well - known pagerank algorithm . extensive numerical simulation on many modeled networks demonstrated that the cbr method is more effective in facilitating synchronization than the degree - based reconstructing method and random reconstructing method for ad


The problem of two magnetic impurities in a normal metal exposes the two opposite tendencies in the...

it is well - recognized that the competition between the single - ion kondo effect and the ruderman - kittel - kasuya - yosida ( rkky ) interaction , the two inevitable forces in any kondo systems with more than one local impurity magnetic moment , plays a crucial role in correlated systems ranging from dilute magnetic alloys to heavy fermion compounds . the indirect rkky interaction , namely the interimpurity interaction mediated by conduction electrons via a short - range ( on - site ) kondo coupling , oscillates and decays with the interimpurity distance and fermi momentum . when the rkky interaction grows toward the strong antiferromagnetic limit , the quantum many - body ground state will evolve from a collective kondo singlet state into the interimpurity singlet state locked by the rkky interaction . however , whether a distinct separation or a quantum critical point exists between the two singlet ground states has remained elusive . this theoretical issue has a fundamental importance as it closely correlates with the critical divergence or scaling behavior of several physical quantities , or emergent energy scales in realistic materials . it is remarkable that even for the simplest case with only two local impurities , i.e. , the two - impurity kondo model ( tikm) , the evidences for a quantum critical point separating the two distinct singlet states do not converge . on the one hand , the early numerical renormalization group ( nrg ) studies revealed an unstable fixed point characterized by diverging impurity staggered susceptibility and coefficient of specific heat at a finite ratio of the rkky interaction to the kondo temperature ( ) . on the other hand , the subsequent well - controlled quantum monte carlo ( qmc ) studies did not find such a divergence , instead , a crossover behavior in the corresponding quantities at very low but still finite temperatures was observed . since then , although the effective field theory analysis suggested the occurrence o

We present a new theoretical study of the interaction between the single - ion kondo effect and the ruderman - kittel -kasuya -yosida ( rkky ) interaction in two - impurity k Mondelez - de la scénat, a model with a finite number of local impurities. The results are consistent with the experimental data for the first time, which show that the quantum critical point exists between the two distinct ground states.

the problem of two magnetic impurities in a normal metal exposes the two opposite tendencies in the formation of a singlet ground state , driven respectively by the single - ion kondo effect with conduction electrons to screen impurity spins or the ruderman - kittel - kasuya - yosida interaction between the two impurities to directly form impurity spin singlet . however , whether the competition between these two tendencies can lead to a quantum critical point has been debated over more than two


We consider deeply virtual compton scattering and deep inelastic scattering in presence of regge...

in the past two decades , notable theoretical activity has been dedicated to the study of the generalized parton distributions ( gpd s ) . gpd s allow one to access the nucleon structure in a more detailed manner than the parton distribution functions ( pdf s ) studied within dis paradigm , and are a direct generalization of the latter . to access gpd s , it was proposed to study hard exclusive processes like deeply virtual compton scattering , ( dvcs ) or meson electroproduction , , at high virtuality of the photon originating from the scattered lepton , and low momentum transfer between recoiled and target nucleon . at present dvcs has been studied experimentally at hera and jefferson lab . interpretability of hard exclusive processes in terms of the gpd s that are universal objects for all such reaction , is empowered by the collinear factorization theorem that , similarly as for dis , allows for a separation of the soft hadronic amplitude from perturbative , qcd process with the former leading to four gpd s . to the lowest order in the qcd coupling , , the full amplitude then corresponds to the handbag diagram depicted in fig . [ fig : handbag ] . paratactical applications , however , rest upon , the a priori unknown rate of convergence of the perturbative expansion . at low bjorken- qcd corrections to the handbag diagram involve large logarithms in both and . while significant progress has been made in devising various resumation schemes , to date no first principle solution for the scattering amplitude exists . it is also accepted that the natural physical interpretation of the low- dis is quite different from that of parton model description of the valence region . that many orders in the expansion may been needed to describe the low- region is consistent with the ample evidence that in exclusive electroproduction nonperturbative phenomena play an important role in the nominally perturbative domain . the structure functions at low- have the behavior character

We study the amplitude of deep virtual compton scattering ( dvcs ) at high virtuality of the photon originating from the scattered lepton and low momentum transfer between recoiled and target nucleon. The a priori unknown rate of convergence of the perturbative expansion is a key factor for the interpretation of the low- dis. In this paper, we present a first principle solution to the scattering amplititude of the d - bjorken- qcd process, which allows us to obtain a generalized parton.

we consider deeply virtual compton scattering and deep inelastic scattering in presence of regge exchanges that are part of the non - perturbative quark - nucleon amplitude . in particular we discuss contribution from the pomeron exchange and demonstrate how it leads to regge scaling of the compton amplitude . comparison with hera data is given .


The reaction at low energies is studied with a chiral quark model approach

our knowledge about resonances is much poorer than that of nucleon resonances . even for the well - established low - lying negative parity states , such as , and , their properties are still controversial . up to now we can not clarify whether these states are excited three quark states , dynamically generated resonances , three quark states containing multi - quark components or the other explanations , although there are extensive discussions about their natures . recently , we systematically studied the reactions in a chiral quark model approach . obvious roles of the low - lying negative parity states , , and , are found in the reactions , where we have extracted their strong coupling properties . for example , we found that should have a very weak coupling to , while needs a strong coupling to , which can not be well explained with the symmetry constituent quark model in the limit . to obtain more strong coupling properties and better understandings of these low - lying resonances , in this work , we will continue to study another important reaction . this reaction provides us a very clear place to study the low - lying resonances , because only the resonances contribute here due to the isospin selection rule . especially , the poorly known strong coupling of to might be reliably obtained from the , for this reaction at threshold is dominated by formation of the . recently , the new data of the reaction from crystal ball collaboration were analyzed with an effective lagrangian model by liu and xie . they might find some evidence of a exotic -wave resonance with mass mev and width mev in the reaction , which will be discussed in present work as well . furthermore , to understand the natures of these strong coupling properties extracted from the scattering , we will further carry out a systematical study of the strong decays of the low - lying negative parity resonances in the chiral quark model approach as well . combing the strong coupling properties extracted

We study the strong decays of the low - lying negative parity resonances in the chiral quark model approach. We find that the weak coupling to is very weak and needs a strong coupling, which can not be well explained with the symmetry constituent quark models in the limit. For this reaction, we have extracted their strong couping properties from the scattering.

the reaction at low energies is studied with a chiral quark model approach . good descriptions of the existing experimental data are obtained . it is found that dominates the reaction around threshold . furthermore , - and -channel backgrounds play crucial roles in this reaction as well . the contributions from the -wave state are negligibly small for its tiny coupling to . to understand the strong coupling properties of the low - lying negative parity resonances extracted from the scattering ,


We investigate the evolution of binary fractions in star clusters using -body models of up to stars

the binary content of a globular cluster is important in determining the frequency and nature of cluster stellar exotica , as well as the dynamical evolution of the cluster . it has long been recognized that binary formation is inevitable in a self - gravitating system - body calculations published . they were continued until the first binary formed , at which point the calculations were halted . ] . indeed , the presence of binaries as a central energy source is vital to avoid complete core - collapse ( goodman & hut 1989 ) . however , only more recently has it been realised that globular clusters must also have formed with a sizeable binary population ( see hut et al . 1992 for an early review ) . that globular clusters harbour a mixture of dynamically formed and primordial binaries can be used to understand observations of their stellar content , such as the diverse blue straggler population in 47 tucanae ( mapelli et al . 2004 ) . knowledge of the likely primordial binary fraction of globular clusters is essential as input to models of globular cluster evolution . it also provides a constraint on the cluster formation process . considering that the presence of binaries in the cluster core has a pronounced effect on the core properties and cluster evolution ( hut 1996 ) , knowledge of the central binary frequency is also important . indications are that this is relatively small of the order of 20% ( e.g. bellazzini et al . 2002 ) or less ( e.g. cool & bolton 2002 ) when compared to the frequencies of binaries observed in the solar neighbourhood ( duquennoy & mayor 1991 ) and open clusters such as m67 ( fan et al . 1996 ) which are of the order of 50% . it would be particularly useful to take measurements of the current binary fraction in globular clusters whether that be in the core or outer regions and extrapolate backwards to gain a reliable determination of the primordial binary content . however , processes involved in the intervening cluster evolution make t

We present a new method for determining the binary content of globular clusters. We use the tetrahedral - based method to obtain a reliable determination of the binary fraction in globular clusters and compare it with the results obtained by a self - gravitating system - body calculation. The method is based on the spherical - model, which allows us to extract the binary contents from the core or outer regions of the cluster. Our method is also applicable to the globulation of a cluster, such.

we investigate the evolution of binary fractions in star clusters using -body models of up to stars . primordial binary frequencies in these models range from 5% to 50% . simulations are performed with the nbody4 code and include a full mass spectrum of stars , stellar evolution , binary evolution and the tidal field of the galaxy . we find that the overall binary fraction of a cluster almost always remains close to the primordial value , except at late times when a cluster is near dissolution .


The cp - restoring phase transition at and high temperature is investigated using two related...

the nambu - jona - lasinio ( njl ) model , introduced in refs . , is a model for low energy qcd that contains four - point interactions between the quarks . in this paper the following form of the njl model is used , in the notation of ref . where is the current quark mass . in contrast to ref . , here the up and down quark masses are taken equal , which matters little for our present purposes . furthermore , ,\ ] ] is the attractive part of the channel of the fierz transformed color current - current interaction and is the t hooft determinant interaction which depends on the qcd vacuum angle and describes the effects of instantons . in the literature and are often taken equal , which at means that the low energy spectrum consists of and fields only , but here we will allow them to be different . we will restrict to the two flavor case , using with as generators of u(2 ) . we will not consider nonzero baryon or isospin chemical potential . the symmetry structure of the njl model is very similar to that of qcd . in the absence of quark masses and the instanton interaction , there is a global su(3)u(2)u(2)-symmetry . the instanton interaction breaks it to su(3)su(2)su(2)u(1) . for nonzero , but equal quark masses this symmetry is reduced to su(3)su(2)u(1) . we choose the parameters the same way as in refs . this means we write where the parameter controls the instanton interaction , while the value for the quark condensate at ( which is determined by the combination ) is kept fixed . for our numerical studies we will use the following values for the parameters : mev , a three - dimensional momentum uv cut - off mev/ and . these values lead to a pion mass of mev , a pion decay constant of mev and finally , a quark condensate , all in reasonable agreement with experimental determinations . to calculate the ground state of the theory , the effective potential has to be minimized . in this section the effective potential is calculated in the mean - field approximation . i

We present a numerical study of the ground state of the nambu - jona - lasinio model for low energy qcd. The ground states are determined by the pion mass and the uv cut - off mev/ and. We use the following values for the parameters: mev, a three -dimensional momentum uV cut -off mev and finally, the quark condensate.

the cp - restoring phase transition at and high temperature is investigated using two related models that aim to describe the low - energy phenomenology of qcd , the njl model and the linear sigma model coupled to quarks . despite many similarities between the models , different predictions for the order of the phase transition result . using the landau - ginzburg formalism , the origin of this difference is traced back to a non - analytic vacuum term at zero temperature that is present in the n


We review some of the recent achievements of the joint physics analysis center , a theoretical...

one of the many challenges of physics is to achieve a comprehensive understanding of the phenomena produced by strong coupling quantum chromodynamics ( qcd ) , responsible for the binding of quarks inside hadrons and for more than 95% of the mass of the visible universe . hadrons are color singlets due to color confinement . hence , the simplest structures are ( quark - antiquark ) for mesons and ( 3-quarks ) for baryons . however , there are many other ways we could build color neutral hadrons , for example : glueballs made out of a number of gluons , multi - quark states such as tetraquarks ( ) or pentaquarks ( ) , hybrid mesons and baryons with gluonic components ( and ) and so on . for a recent , brief and pedagogical summary of the current status of hadron physics we refer the reader to . in the last years we have witnessed a dramatic advancement in detection techniques and accelerator technologies from the experimental side and algorithms for first principle qcd analyses on the theoretical side . consequently , many experimental facilities throughout the world have research programs on hadron spectroscopy , among them : lhcb , cms and compass at cern ( geneve , switzerland ) , clas12 and gluex at jefferson lab ( newport news va , usa ) , besiii at the beijing electron positron collider ( beijing , china ) , kloe2 at laboratori nazionali di frascati ( frascati , italy ) , belleii at kek ( tsukuba , japan ) , the hadron experimental facility at j - parc ( tokai , japan ) , and ( hopefully ) the future panda at fair ( darmstadt , germany ) . as a result , several candidates for _ exotic _ hadrons beyond the and picture have been discovered both in the meson and baryon sectors . given the experimental and theoretical interest on hadron spectroscopy , the joint physics analysis center ( jpac ) was set up to develop theoretical and phenomenological analysis methods to support hadron physics experiments . it started out in 2013 with 8 researchers , as a joint venture

We present a new method for the detection of color neutral hadrons in the meson and baryons. This method is based on the spectral analysis of the gluons in the tetraquarks ( ) and pentaquark ( ), both of which are derived from the qcd theory. The method is applied to the spectra of the mesons and barion, as well as to the photons in a hybrid meson.

we review some of the recent achievements of the joint physics analysis center , a theoretical collaboration with ties to experimental collaborations , that aims to provide amplitudes suitable for the analysis of the current and forthcoming experimental data on hadron physics . since its foundation in 2013 , the group is focused on hadron spectroscopy in preparation for the forthcoming high statistics and high precision experimental data from belleii , besiii , clas12 , compass , gluex , lhcb an


We investigate coulomb blockade thermometers ( cbt ) in an intermediate temperature regime , where...

since the single electron tunneling phenomena were described about 30 years ago , many devices based on small tunnel junctions have been demonstrated . an example of such a device is the coulomb blockade thermometer ( cbt ) using one or two dimensional arrays of tunnel junctions . cbt based on electron tunneling enables one to relate the measured voltage to temperature with the help of boltzmann constant , which could thus provide a means to revise the definition of kelvin . a related idea forms the basis of shot - noise thermometry , described in refs . cbt thermometry is based on the change of electrical conductance of tunnel junction arrays . typically , cbt works in a weak coulomb blockade regime , where the charging energy of the system with junctions in series is e^2/c_{}$ ] and is the total capacitance of an island between the junctions that depends on the physical size of the contact and the self capacitance of the island . in this regime , cbt sensor works as a primary thermometer , meaning that calibration is not needed . for a uniform array , the differential conductance scaled by its asymptotic value at large positive and negative voltages can be written in terms of bias voltage as where the function /[8 ^4(x/2)]$ ] determines the bias dependence . primary measurements of temperature can be achieved from the measurement of full width of the conductance dip at half minimum thus , obtained temperature does not depend on the geometry or material of a sensor . a secondary temperature measurement can be obtained by recording the depth of the zero bias conductance dip with parameter . as was shown in ref . , at high temperature ( in that case 4.2 k ) the measured conductances follow quite well the expression in eq . ( [ eq.3 ] ) . in this letter , we demonstrate experimentally the extension of coulomb blockade thermometry into an intermediate temperature regime described theoretically in refs . . experiments employing quantum dot thermometry , investigating el

We present a new method for measuring the temperature of coulomb blockade thermometers using quantum dot thermometry. This technique is based on the change of electrical conductance of tunnel junction arrays. The measured conductances are scaled by their asymptotic value at large positive and negative voltages, which can be written in terms of bias voltage. We show that the measured Conductances follow quite well the expression in eq.

we investigate coulomb blockade thermometers ( cbt ) in an intermediate temperature regime , where measurements with enhanced accuracy are possible due to the increased magnitude of the differential conductance dip . previous theoretical results show that corrections to the half width and to the depth of the measured conductance dip of a sensor are needed , when leaving the regime of weak coulomb blockade towards lower temperatures . in the present work , we demonstrate experimentally that the t


Most models for barrier pricing are designed to let a market maker tune the model - implied...

barrier option pricing is sensitive to parameters of stochastic volatility models mostly through what the model implies about the covariance between the asset spot price and the implied volatility skew ( see appendix [ bardepcorr ] for an elaboration of this intuition ) . in most markets there is indeed significant positive realized correlation between spot and volatility skew , and this dynamic can materially impact fair prices for barrier options . in foreign exchange markets , where barrier options are a liquid vanilla exotic " product , this is generally implemented with some flavor of local volatility / stochastic volatility ( lvsv ) mixture model ( for example , ) . a typical formulation is : here , is the asset spot price and represents a stochastic factor on the instantaneous variance that follows a mean - reverting square root process . is the normal risk - neutral drift of spot , equal to the discount rate minus the asset discount rate . in this lvsv model the local volatility term is calibrated to to implied volatilities and fills in " whatever match to implied volatilities is not handled by the pure stochastic volatility piece . this construction means that the volatility of volatility parameter effectively controls the mixture between local and stochastic volatility , and therefore the amount that implied volatility skew moves when the asset spot price moves . in the limit where goes to zero , lvsv is a pure local volatility model , where the model s implied volatility skew moves maximally as the spot price moves . in the limit where and are set such that , with constant , the model most closely matches the market implied volatilities , lvsv s implied volatility skew moves the least as spot moves . therefore , in lvsv , the parameter controls the model - implied covariance between spot and implied volatility skew . however , it suffers from the same key problem as a pure local volatilty model : the contribution to forward skew and smile from the local v

We present a new method for calculating the local volatility skew in barrier option pricing. This method is based on the lvsv model, where the local skewitness parameter is calibrated to the market implied volatilities and filled in. The skewie of the local stochastic volatility parameter is determined by the -valued -price - skewitz - lattice. We show that the kev - lemmon - de - marquette - peterson ( kem ).

most models for barrier pricing are designed to let a market maker tune the model - implied covariance between moves in the asset spot price and moves in the implied volatility skew . this is often implemented with a local volatility / stochastic volatility mixture model , where the mixture parameter tunes that covariance . this paper defines an alternate model where the spot / volatility correlation is a separate mean - reverting stochastic variable which is itself correlated with spot . we als