Some remarks on quasi-Hermitian operators
Antoine, Jean-Pierre, E-mail: jean-pierre.antoine@uclouvain.be [Institut de Recherche en Mathématique et Physique, Université Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Trapani, Camillo, E-mail: camillo.trapani@unipa.it [Dipartimento di Matematica e Informatica, Università di Palermo, I-90123, Palermo (Italy)
2014-01-15
A quasi-Hermitian operator is an operator that is similar to its adjoint in some sense, via a metric operator, i.e., a strictly positive self-adjoint operator. Whereas those metric operators are in general assumed to be bounded, we analyze the structure generated by unbounded metric operators in a Hilbert space. Following our previous work, we introduce several generalizations of the notion of similarity between operators. Then we explore systematically the various types of quasi-Hermitian operators, bounded or not. Finally, we discuss their application in the so-called pseudo-Hermitian quantum mechanics.
Bender, Carl M.; Fring, Andreas; Guenther, Uwe; Jones, Hugh F.
2012-01-01
This is a call for contributions to a special issue of Journal of Physics A: Mathematical and Theoretical dedicated to quantum physics with non-Hermitian operators. The main motivation behind this special issue is to gather together recent results, developments and open problems in this rapidly evolving field of research in a single comprehensive volume. We expect that such a special issue will become a valuable reference for the broad scientific community working in mathematical and theoretical physics. The issue will be open to all contributions containing new results on non-Hermitian theories which are explicitly PT-symmetric and/or pseudo-Hermitian or quasi-Hermitian. The main novelties in the past years in this area have been many experimental observations, realizations, and applications of PT symmetric Hamiltonians in optics and microwave cavities. We especially invite contributions on the theoretical interpretations of these recent PT-symmetric experiments and on theoretical proposals for new experiments. Editorial policy The Guest Editors for this issue are Carl Bender, Andreas Fring, Uwe Guenther and Hugh Jones. The areas and topics for this issue include, but are not limited to: spectral problems novel properties of complex optical potentials PT-symmetry related threshold lasers and spectral singularities construction of metric operators scattering theory supersymmetric theories Lie algebraic and Krein-space methods random matrix models classical and semi-classical models exceptional points in model systems operator theoretic approaches microwave cavities aspects of integrability and exact solvability field theories with indefinite metric All contributions will be refereed and processed according to the usual procedure of the journal. Papers should report original and significant research that has not already been published. Guidelines for preparation of contributions The deadline for contributed papers will be 31 March 2012. This deadline will allow the
Non-Hermitian Operator Modelling of Basic Cancer Cell Dynamics
Bagarello, Fabio; Gargano, Francesco
2018-04-01
We propose a dynamical system of tumor cells proliferation based on operatorial methods. The approach we propose is quantum-like: we use ladder and number operators to describe healthy and tumor cells birth and death, and the evolution is ruled by a non-hermitian Hamiltonian which includes, in a non reversible way, the basic biological mechanisms we consider for the system. We show that this approach is rather efficient in describing some processes of the cells. We further add some medical treatment, described by adding a suitable term in the Hamiltonian, which controls and limits the growth of tumor cells, and we propose an optimal approach to stop, and reverse, this growth.
Some applicationS of non-Hermitian operators in quantum mechanics and quantum field theory
Recami, E.; Rodrigues, W.A. Jr.; Smrz, P.
1983-01-01
Due to the possibility of rephrasing it in terms of Lie-admissible algebras, some work done in the past in collaboration with A., Agodi, M., Baldo and V.S., Olkhovsky is here reported. Such work led to the introduction of non-Hermitian operators in (classical and relativistic) quantum theory. In particular: (i) the association of unstable states (decaying 'Resonances') with the eigenvectors of non-Hermitian hamiltonians; (ii) the problem of the four position operators for relativistic spin-zero particles are dealth with
On Some Analytic Operator Functions in the Theory of Hermitian Operators
Perch Melik-Adamyan
2014-01-01
Full Text Available A densely defined Hermitian operator $A_0$ with equal defect numbers is considered. Presentable by means of resolvents of a certain maximal dissipative or accumulative extensions of $A_0$, bounded linear operators acting from some defect subspace $\\mfn_\\gamma$ to arbitrary other $\\mfn_\\lambda$ are investigated. With their aid are discussed characteristic and Weyl functions. A family of Weyl functions is described, associated with a given self-adjoint extension of $A_0$. The specific property of Weyl function's factors enabled to obtain a modified formulas of von Neumann. In terms of characteristic and Weyl functions of suitably chosen extensions the resolvent of Weyl function is presented explicitly.
Inequalities among partial traces of hermitian operators and partial sums of their eigenvalues
Daboul, J.
1990-01-01
Two different proofs of the following inequality are given: Tr sup(k)(H):= sup(k)Σ sub(i=1) h sub(i) :sup(k)Σ sub(i=1)(X sub(i), Hx sub(i))≥ sup(k)Σ sub(i=1)E sub(i), for k = 1,-,N, where H is a Hermitian matrix, the {X sub(i), i = 1,2-,k } are any k orthonormal vectors and the e sub(i) are the eigenvalues of H, ordered according to increasing values. This result is a generalization of the well-known fact, that ground state of a Hamiltonian is given by its lowest eigenvalue, E sub(i). It can also be regarded as a generalization, for Hermitian operators, of the invariance of the trace under unitary transformation. A few consequences of the above result are also derived. (author)
Comment on 'New ansatz for metric operator calculation in pseudo-Hermitian field theory'
Bender, Carl M.; Benincasa, Gregorio; Jones, H. F.
2009-01-01
In a recent Brief Report by Shalaby, a new first-order perturbative calculation of the metric operator for an iφ 3 scalar field theory is given. It is claimed that the incorporation of derivative terms in the ansatz for the metric operator results in a local solution, in contrast to the nonlocal solution previously obtained by Bender, Brody, and Jones. Unfortunately, Shalaby's calculation is not valid because of sign errors.
Cuesta, Vladimir; Vergara, Jose David; Montesinos, Merced
2011-01-01
We work with gauge systems and using gauge invariant functions we study its quantum counterpart and we find if all these operators are self adjoint or not. Our study is divided in two cases, when we choose clock or clocks that its Poisson brackets with the set of constraints is one or it is different to one. We show some transition amplitudes.
Pseudospectra in non-Hermitian quantum mechanics
Krejčiřík, D.; Siegl, P.; Tater, M.; Viola, J.
2015-10-01
We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis properties of eigenfunctions. The abstract results are illustrated by unexpected wild properties of operators familiar from PT -symmetric quantum mechanics.
Hermitian harmonic maps into convex balls
Li Zhenyang; Xi Zhang
2004-07-01
In this paper, we consider Hermitian harmonic maps from Hermitian manifolds into convex balls. We prove that there exist no non-trivial Hermitian harmonic maps from closed Hermitian manifolds into convex balls, and we use the heat flow method to solve the Dirichlet problem for Hermitian harmonic maps when the domain is compact Hermitian manifold with non-empty boundary. The case where the domain manifold is complete(noncompact) is also studied. (author)
Hermitian-Einstein metrics on holomorphic vector bundles over Hermitian manifolds
Xi Zhang
2004-07-01
In this paper, we prove the long-time existence of the Hermitian-Einstein flow on a holomorphic vector bundle over a compact Hermitian (non-kaehler) manifold, and solve the Dirichlet problem for the Hermitian-Einstein equations. We also prove the existence of Hermitian-Einstein metrics for holomorphic vector bundles on a class of complete noncompact Hermitian manifolds. (author)
Znojil, Miloslav; Geyer, HB.
2007-01-01
Roč. 649, 5-6 (2007), s. 494-494 ISSN 0370-2693 R&D Projects: GA ČR GA202/07/1307 Institutional research plan: CEZ:AV0Z10480505 Keywords : metrics * quasi-Hermitian * charge Subject RIV: BE - Theoretical Physics Impact factor: 4.189, year: 2007
Dirichlet problem for Hermitian-Einstein equations over almost Hermitian manifolds
Xi Zhang
2004-07-01
In this paper, we investigate the Dirichlet problem for Hermitian-Einstein equations on complex vector bundle over almost Hermitian manifolds, and we obtain the unique solubility of the Dirichlet problem for Hermitian-Einstein equations. (author)
Non-Hermitian spin chains with inhomogeneous coupling
Bytsko, Andrei G. [Rossijskaya Akademiya Nauk, St. Petersburg (Russian Federation). Inst. Matematiki; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie
2009-11-15
An open U{sub q}(sl{sub 2})-invariant spin chain of spin S and length N with inhomogeneous coupling is investigated as an example of a non-Hermitian (quasi-Hermitian) model. For several particular cases of such a chain, the ranges of the deformation parameter {gamma} are determined for which the spectrum of the model is real. For a certain range of {gamma}, a universal metric operator is constructed and thus the quasi-Hermiticity of the model is established. The constructed metric operator is non-dynamical, its structure is determined only by the symmetry of the model. The results apply, in particular, to all known homogeneous U{sub q}(sl{sub 2})-invariant integrable spin chains with nearest-neighbour interaction. In addition, the most general form of a metric operator for a quasi-Hermitian operator in finite dimensional space is discussed. (orig.)
Krejčiřík, David; Siegl, Petr; Železný, Jakub
2014-01-01
Roč. 8, č. 1 (2014), s. 255-281 ISSN 1661-8254 R&D Projects: GA MŠk LC06002; GA MŠk LC527; GA ČR GAP203/11/0701 Grant - others:GA ČR(CZ) GD202/08/H072 Institutional support: RVO:61389005 Keywords : Sturm-Liouville operators * non-symmetric Robin boundary conditions * similarity to normal or self-adjoint operators * discrete spectral operator * complex symmetric operator * PT-symmetry * metric operator * C operator * Hilbert- Schmidt operators Subject RIV: BE - Theoretical Physics Impact factor: 0.545, year: 2014
Quantum entropy of systems described by non-Hermitian Hamiltonians
Sergi, Alessandro; Zloshchastiev, Konstantin G
2016-01-01
We study the quantum entropy of systems that are described by general non-Hermitian Hamiltonians, including those which can model the effects of sinks or sources. We generalize the von Neumann entropy to the non-Hermitian case and find that one needs both the normalized and non-normalized density operators in order to properly describe irreversible processes. It turns out that such a generalization monitors the onset of disorder in quantum dissipative systems. We give arguments for why one can consider the generalized entropy as the informational entropy describing the flow of information between the system and the bath. We illustrate the theory by explicitly studying few simple models, including tunneling systems with two energy levels and non-Hermitian detuning. (paper: quantum statistical physics, condensed matter, integrable systems)
Non-Hermitian Heisenberg representation
Znojil, Miloslav
2015-01-01
Roč. 379, č. 36 (2015), s. 2013-2017 ISSN 0375-9601 Institutional support: RVO:61389005 Keywords : quantum mechanics * Non-Hermitian representation of observables * Generalized Heisenberg equations Subject RIV: BE - Theoretical Physics Impact factor: 1.677, year: 2015
15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics
Passante, Roberto; Trapani, Camillo
2016-01-01
This book presents the Proceedings of the 15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics, held in Palermo, Italy, from 18 to 23 May 2015. Non-Hermitian operators, and non-Hermitian Hamiltonians in particular, have recently received considerable attention from both the mathematics and physics communities. There has been a growing interest in non-Hermitian Hamiltonians in quantum physics since the discovery that PT-symmetric Hamiltonians can have a real spectrum and thus a physical relevance. The main subjects considered in this book include: PT-symmetry in quantum physics, PT-optics, Spectral singularities and spectral techniques, Indefinite-metric theories, Open quantum systems, Krein space methods, and Biorthogonal systems and applications. The book also provides a summary of recent advances in pseudo-Hermitian Hamiltonians and PT-symmetric Hamiltonians, as well as their applications in quantum physics and in the theory of open quantum systems.
Yahiaoui, S A; Bentaiba, M
2012-01-01
In the context of the factorization method, we investigate the pseudo-Hermitian coherent states and their Hermitian counterpart coherent states under the generalized quantum condition in the framework of a position-dependent mass. By considering a specific modification in the superpotential, suitable annihilation and creation operators are constructed in order to reproduce the Hermitian counterpart Hamiltonian in the factorized form. We show that by means of these ladder operators, we can construct a wide range of exactly solvable potentials as well as their accompanying coherent states. Alternatively, we explore the relationship between the pseudo-Hermitian Hamiltonian and its Hermitian counterparts, obtained from a similarity transformation, to construct the associated pseudo-Hermitian coherent states. These latter preserve the structure of Perelomov’s states and minimize the generalized position–momentum uncertainty principle. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)
Supersymmetric Extension of Non-Hermitian su(2 Hamiltonian and Supercoherent States
Omar Cherbal
2010-12-01
Full Text Available A new class of non-Hermitian Hamiltonians with real spectrum, which are written as a real linear combination of su(2 generators in the form H=ωJ_3+αJ_−+βJ_+, α≠β, is analyzed. The metrics which allows the transition to the equivalent Hermitian Hamiltonian is established. A pseudo-Hermitian supersymmetic extension of such Hamiltonians is performed. They correspond to the pseudo-Hermitian supersymmetric systems of the boson-phermion oscillators. We extend the supercoherent states formalism to such supersymmetic systems via the pseudo-unitary supersymmetric displacement operator method. The constructed family of these supercoherent states consists of two dual subfamilies that form a bi-overcomplete and bi-normal system in the boson-phermion Fock space. The states of each subfamily are eigenvectors of the boson annihilation operator and of one of the two phermion lowering operators.
Physical aspects of pseudo-Hermitian and PT-symmetric quantum mechanics
Mostafazadeh, Ali; Batal, Ahmet
2004-01-01
For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a canonical orthonormal basis in which a previously introduced unitary mapping of H to a Hermitian Hamiltonian h takes a simple form. We use this basis to construct the observables O α of the quantum mechanics based on H. In particular, we introduce pseudo-Hermitian position and momentum operators and a pseudo-Hermitian quantization scheme that relates the latter to the ordinary classical position and momentum observables. These allow us to address the problem of determining the conserved probability density and the underlying classical system for pseudo-Hermitian and in particular PT-symmetric quantum systems. As a concrete example we construct the Hermitian Hamiltonian h, the physical observables O α , the localized states and the conserved probability density for the non-Hermitian PT-symmetric square well. We achieve this by employing an appropriate perturbation scheme. For this system, we conduct a comprehensive study of both the kinematical and dynamical effects of the non-Hermiticity of the Hamiltonian on various physical quantities. In particular, we show that these effects are quantum mechanical in nature and diminish in the classical limit. Our results provide an objective assessment of the physical aspects of PT-symmetric quantum mechanics and clarify its relationship with both conventional quantum mechanics and classical mechanics
Hermitian relativity, chromodynamics and confinement
Treder, H.J.
1983-01-01
The extension of the Riemann metrics of General Relativity to the complex domain (substitution of the symmetry conditions for the fundamental tensor, the affinity and the Ricci curvature by the conditions of hermicity) leads to a 'Generalized Theory of Gravity' (Einstein) describing the Newton-Einstein gravodynamics combined with the chromodynamics of quarks. The interaction of gravodynamics and chromodynamics implied by the Einstein-Schroedinger field equations of the hermitian relativity theory enforces the 'confinement'. The 'confinement' prevents the gravitational potential from divergence which would result in the lack of a Riemann space-time metric
Non-Hermitian optics in atomic systems
Zhang, Zhaoyang; Ma, Danmeng; Sheng, Jiteng; Zhang, Yiqi; Zhang, Yanpeng; Xiao, Min
2018-04-01
A wide class of non-Hermitian Hamiltonians can possess entirely real eigenvalues when they have parity-time (PT) symmetric potentials. Recently, this family of non-Hermitian systems has attracted considerable attention in diverse areas of physics due to their extraordinary properties, especially in optical systems based on solid-state materials, such as coupled gain-loss waveguides and microcavities. Considering the desired refractive index can be effectively manipulated through atomic coherence, it is important to realize such non-Hermitian optical potentials and further investigate their distinct properties in atomic systems. In this paper, we review the recent theoretical and experimental progress of non-Hermitian optics with coherently prepared multi-level atomic configurations. The realizations of (anti-) PT symmetry with different schemes have extensively demonstrated the special optical properties of non-Hermitian optical systems with atomic coherence.
Equivalent Hermitian Hamiltonian for the non-Hermitian -x4 potential
Jones, H.F.; Mateo, J.
2006-01-01
The potential V(x)=-x 4 , which is unbounded below on the real line, can give rise to a well-posed bound state problem when x is taken on a contour in the lower-half complex plane. It is then PT-symmetric rather than Hermitian. Nonetheless it has been shown numerically to have a real spectrum, and a proof of reality, involving the correspondence between ordinary differential equations and integrable systems, was subsequently constructed for the general class of potentials -(ix) N . For such Hamiltonians the natural PT metric is not positive definite, but a dynamically-defined positive-definite metric can be defined, depending on an operator Q. Further, with the help of this operator an equivalent Hermitian Hamiltonian h can be constructed. This programme has been carried out exactly for a few soluble models, and the first few terms of a perturbative expansion have been found for the potential m 2 x 2 +igx 3 . However, until now, the -x 4 potential has proved intractable. In the present paper we give explicit, closed form expressions for Q and h, which are made possible by a particular parametrization of the contour in the complex plane on which the problem is defined. This constitutes an explicit proof of the reality of the spectrum. The resulting equivalent Hamiltonian has a potential with a positive quartic term together with a linear term
Faster than Hermitian Quantum Mechanics
Bender, Carl M.; Brody, Dorje C.; Jones, Hugh F.; Meister, Bernhard K.
2007-01-01
Given an initial quantum state vertical bar ψ I > and a final quantum state vertical bar ψ F >, there exist Hamiltonians H under which vertical bar ψ I > evolves into vertical bar ψ F >. Consider the following quantum brachistochrone problem: subject to the constraint that the difference between the largest and smallest eigenvalues of H is held fixed, which H achieves this transformation in the least time τ? For Hermitian Hamiltonians τ has a nonzero lower bound. However, among non-Hermitian PT-symmetric Hamiltonians satisfying the same energy constraint, τ can be made arbitrarily small without violating the time-energy uncertainty principle. This is because for such Hamiltonians the path from vertical bar ψ I > to vertical bar ψ F > can be made short. The mechanism described here is similar to that in general relativity in which the distance between two space-time points can be made small if they are connected by a wormhole. This result may have applications in quantum computing
A possible method for non-Hermitian and Non-PT-symmetric Hamiltonian systems.
Jun-Qing Li
Full Text Available A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator η+ and defining the annihilation and creation operators to be η+ -pseudo-Hermitian adjoint to each other. The operator η+ represents the η+ -pseudo-Hermiticity of Hamiltonians. As an example, a non-Hermitian and non-PT-symmetric Hamiltonian with imaginary linear coordinate and linear momentum terms is constructed and analyzed in detail. The operator η+ is found, based on which, a real spectrum and a positive-definite inner product, together with the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution, are obtained for the non-Hermitian and non-PT-symmetric Hamiltonian. Moreover, this Hamiltonian turns out to be coupled when it is extended to the canonical noncommutative space with noncommutative spatial coordinate operators and noncommutative momentum operators as well. Our method is applicable to the coupled Hamiltonian. Then the first and second order noncommutative corrections of energy levels are calculated, and in particular the reality of energy spectra, the positive-definiteness of inner products, and the related properties (the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution are found not to be altered by the noncommutativity.
New quasi-exactly solvable Hermitian as well as non-Hermitian PT ...
We start with quasi-exactly solvable (QES) Hermitian (and hence real) as well as complex P T -invariant, double sinh-Gordon potential and show that even after adding perturbation terms, the resulting potentials, in both cases, are still QES potentials. Further, by using anti-isospectral transformations, we obtain Hermitian as ...
Balanced Hermitian metrics from SU(2)-structures
Fernandez, M.; Tomassini, A.; Ugarte, L.; Villacampa, R.
2009-01-01
We study the intrinsic geometrical structure of hypersurfaces in six-manifolds carrying a balanced Hermitian SU(3)-structure, which we call balanced SU(2)-structure. We provide sufficient conditions, in terms of suitable evolution equations, which imply that a five-manifold with such structure can be isometrically embedded as a hypersurface in a balanced Hermitian SU(3)-manifold. Any five-dimensional compact nilmanifold has an invariant balanced SU(2)-structure, and we show how some of them can be evolved to give new explicit examples of balanced Hermitian SU(3)-structures. Moreover, for n=3,4, we present examples of compact solvmanifolds endowed with a balanced SU(n)-structure such that the corresponding Bismut connection has holonomy equal to SU(n)
Decoding Hermitian Codes with Sudan's Algorithm
Høholdt, Tom; Nielsen, Rasmus Refslund
1999-01-01
We present an efficient implementation of Sudan's algorithm for list decoding Hermitian codes beyond half the minimum distance. The main ingredients are an explicit method to calculate so-called increasing zero bases, an efficient interpolation algorithm for finding the Q-polynomial, and a reduct......We present an efficient implementation of Sudan's algorithm for list decoding Hermitian codes beyond half the minimum distance. The main ingredients are an explicit method to calculate so-called increasing zero bases, an efficient interpolation algorithm for finding the Q...
Castro-Alvaredo, Olalla A; Fring, Andreas
2009-01-01
We investigate a lattice version of the Yang-Lee model which is characterized by a non-Hermitian quantum spin chain Hamiltonian. We propose a new way to implement PT-symmetry on the lattice, which serves to guarantee the reality of the spectrum in certain regions of values of the coupling constants. In that region of unbroken PT-symmetry, we construct a Dyson map, a metric operator and find the Hermitian counterpart of the Hamiltonian for small values of the number of sites, both exactly and perturbatively. Besides the standard perturbation theory about the Hermitian part of the Hamiltonian, we also carry out an expansion in the second coupling constant of the model. Our constructions turn out to be unique with the sole assumption that the Dyson map is Hermitian. Finally, we analyse the magnetization of the chain in the z- and x-direction.
Self-dual geometry of generalized Hermitian surfaces
Arsen'eva, O E; Kirichenko, V F
1998-01-01
Several results on the geometry of conformally semiflat Hermitian surfaces of both classical and hyperbolic types (generalized Hermitian surfaces) are obtained. Some of these results are generalizations and clarifications of already known results in this direction due to Koda, Itoh, and other authors. They reveal some unexpected beautiful connections between such classical characteristics of conformally semiflat (generalized) Hermitian surfaces as the Einstein property, the constancy of the holomorphic sectional curvature, and so on. A complete classification of compact self-dual Hermitian RK-surfaces that are at the same time generalized Hopf manifolds is obtained. This provides a complete solution of the Chen problem in this class of Hermitian surfaces
On the subfield subcodes of Hermitian codes
Pinero, Fernando; Janwa, Heeralal
2014-01-01
We present a fast algorithm using Gröbner basis to compute the dimensions of subfield subcodes of Hermitian codes. With these algorithms we are able to compute the exact values of the dimension of all subfield subcodes up to q ≤ 32 and length up to 215. We show that some of the subfield subcodes ...
Concrete minimal 3 × 3 Hermitian matrices and some general cases
Klobouk Abel H.
2017-12-01
Full Text Available Given a Hermitian matrix M ∈ M3(ℂ we describe explicitly the real diagonal matrices DM such that ║M + DM║ ≤ ║M + D║ for all real diagonal matrices D ∈ M3(ℂ, where ║ · ║ denotes the operator norm. Moreover, we generalize our techniques to some n × n cases.
PREFACE: 6th International Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physics
Fring, Andreas; Jones, Hugh; Znojil, Miloslav
2008-06-01
growing community of this subject. It is, for instance, well understood that the reality of the spectrum can be attributed either to the unbroken PT-symmetry of the entire system, that is, invariance of the Hamiltonian and the corresponding wavefunctions under a simultaneous parity transformation and time reversal, or more generally to its pseudo-Hermiticity . When the spectrum is real and discrete the Hamiltonian is actually quasi-Hermitian, with a positive-definite metric operator, and can in principle be related by a similarity transformation to an isospectral Hermitian counterpart. For all approaches well-defined procedures have been developed, which allow one to construct metric operators and therefore a consistent description of the underlying quantum mechanical observables. Even though the general principles have been laid out, it remains a challenge in most concrete cases to implement the entire procedure. Solvable models in this sense, some of which may be found in this issue, remain a rare exception. Nonetheless, despite this progress some important questions are still unanswered. For instance, according to the current understanding the non-Hermitian Hamiltonian does not uniquely define the physics of the system since a meaningful metric can no longer be associated with the system in a non-trivial and unambiguous manner. A fully consistent scattering theory has also not yet been formulated. Other issues remain controversial, such as the quantum brachistochrone problem, the problem of forming a mixture between a Hermitian and non-Hermitian system, the new phenomenological possibilities of forming a kind of worm-hole effect, etc. We would like to acknowledge the financial support of the London Mathematical Society, the Institute of Physics, the Doppler Institute in Prague and the School of Engineering and Mathematical Science of City University London. We hope this special issue will be useful to the newcomer as well as to the expert in the subject. Workshop
General coupled mode theory in non-Hermitian waveguides.
Xu, Jing; Chen, Yuntian
2015-08-24
In the presence of loss and gain, the coupled mode equation on describing the mode hybridization of various waveguides or cavities, or cavities coupled to waveguides becomes intrinsically non-Hermitian. In such non-Hermitian waveguides, the standard coupled mode theory fails. We generalize the coupled mode theory with a properly defined inner product based on reaction conservation. We apply our theory to the non-Hermitian parity-time symmetric waveguides, and obtain excellent agreement with results obtained by finite element fullwave simulations. The theory presented here is typically formulated in space to study coupling between waveguides, which can be transformed into time domain by proper reformulation to study coupling between non-Hermitian resonators. Our theory has the strength of studying non-Hermitian optical systems with inclusion of the full vector fields, thus is useful to study and design non-Hermitian devices that support asymmetric and even nonreciprocal light propagations.
Pseudo-Hermitian description of PT-symmetric systems defined on a complex contour
Mostafazadeh, Ali
2005-01-01
We describe a method that allows for a practical application of the theory of pseudo-Hermitian operators to PT-symmetric systems defined on a complex contour. We apply this method to study the Hamiltonians H = p 2 + x 2 (ix) ν with ν ε (-2, ∞) that are defined along the corresponding anti-Stokes lines. In particular, we reveal the intrinsic non-Hermiticity of H for the cases that ν is an even integer, so that H p 2 ± x 2+ν , and give a proof of the discreteness of the spectrum of H for all ν ε (-2, ∞). Furthermore, we study the consequences of defining a square-well Hamiltonian on a wedge-shaped complex contour. This yields a PT-symmetric system with a finite number of real eigenvalues. We present a comprehensive analysis of this system within the framework of pseudo-Hermitian quantum mechanics. We also outline a direct pseudo-Hermitian treatment of PT-symmetric systems defined on a complex contour which clarifies the underlying mathematical structure of the formulation of PT-symmetric quantum mechanics based on the charge-conjugation operator. Our results provide conclusive evidence that pseudo-Hermitian quantum mechanics provides a complete description of general PT-symmetric systems regardless of whether they are defined along the real line or a complex contour
Projective block Lanczos algorithm for dense, Hermitian eigensystems
Webster, F.; Lo, G.C.
1996-01-01
Projection operators are used to effect open-quotes deflation by restrictionclose quotes and it is argued that this is an optimal Lanczos algorithm for memory minimization. Algorithmic optimization is constrained to dense, Hermitian eigensystems where a significant number of the extreme eigenvectors must be obtained reliably and completely. The defining constraints are operator algebra without a matrix representation and semi-orthogonalization without storage of Krylov vectors. other semi-orthogonalization strategies for Lanczos algorithms and conjugate gradient techniques are evaluated within these constraints. Large scale, sparse, complex numerical experiments are performed on clusters of magnetic dipoles, a quantum many-body system that is not block-diagonalizable. Plane-wave, density functional theory of beryllium clusters provides examples of dense complex eigensystems. Use of preconditioners and spectral transformations is evaluated in a preprocessor prior to a high accuracy self-consistent field calculation. 25 refs., 3 figs., 5 tabs
Designing non-Hermitian dynamics for conservative state evolution on the Bloch sphere
Yu, Sunkyu; Piao, Xianji; Park, Namkyoo
2018-03-01
An evolution on the Bloch sphere is the fundamental state transition, including optical polarization controls and qubit operations. Conventional evolution of a polarization state or qubit is implemented within a closed system that automatically satisfies energy conservation from the Hermitian formalism. Although particular forms of static non-Hermitian Hamiltonians, such as parity-time-symmetric Hamiltonians, allow conservative states in an open system, the criteria for the energy conservation in a dynamical open system have not been fully explored. Here, we derive the condition of conservative state evolution in open-system dynamics and its inverse design method, by developing the non-Hermitian modification of the Larmor precession equation. We show that the geometrically designed locus on the Bloch sphere can be realized by different forms of dynamics, leading to the isolocus family of non-Hermitian dynamics. This increased degree of freedom allows the complementary phenomena of error-robust and highly sensitive evolutions on the Bloch sphere, which could be applicable to stable polarizers, quantum gates, and optimized sensors in dynamical open systems.
New quasi-exactly solvable Hermitian as well as non-Hermitian PT ...
Abstract. We start with quasi-exactly solvable (QES) Hermitian (and hence real) as ... the time reversal transformation t → −t and further, one replaces i → −i. One can ..... F M Fernandez, R Guardiola, J Ros and M Znojil, J. Phys. A32, 3105 ...
Heralded Magnetism in Non-Hermitian Atomic Systems
Tony E. Lee
2014-10-01
Full Text Available Quantum phase transitions are usually studied in terms of Hermitian Hamiltonians. However, cold-atom experiments are intrinsically non-Hermitian because of spontaneous decay. Here, we show that non-Hermitian systems exhibit quantum phase transitions that are beyond the paradigm of Hermitian physics. We consider the non-Hermitian XY model, which can be implemented using three-level atoms with spontaneous decay. We exactly solve the model in one dimension and show that there is a quantum phase transition from short-range order to quasi-long-range order despite the absence of a continuous symmetry in the Hamiltonian. The ordered phase has a frustrated spin pattern. The critical exponent ν can be 1 or 1/2. Our results can be seen experimentally with trapped ions, cavity QED, and atoms in optical lattices.
Critical statistics for non-Hermitian matrices
Garcia-Garcia, A.M.; Verbaarschot, J.J.M.; Nishigaki, S.M.
2002-01-01
We introduce a generalized ensemble of non-Hermitian matrices interpolating between the Gaussian Unitary Ensemble, the Ginibre ensemble, and the Poisson ensemble. The joint eigenvalue distribution of this model is obtained by means of an extension of the Itzykson-Zuber formula to general complex matrices. Its correlation functions are studied both in the case of weak non-Hermiticity and in the case of strong non-Hermiticity. In the weak non-Hermiticity limit we show that the spectral correlations in the bulk of the spectrum display critical statistics: the asymptotic linear behavior of the number variance is already approached for energy differences of the order of the eigenvalue spacing. To lowest order, its slope does not depend on the degree of non-Hermiticity. Close the edge, the spectral correlations are similar to the Hermitian case. In the strong non-Hermiticity limit the crossover behavior from the Ginibre ensemble to the Poisson ensemble first appears close to the surface of the spectrum. Our model may be relevant for the description of the spectral correlations of an open disordered system close to an Anderson transition
Problem of the coexistence of several non-Hermitian observables in PT -symmetric quantum mechanics
Znojil, Miloslav; Semorádová, Iveta; Růžička, František; Moulla, H.; Leghrib, I.
2017-01-01
Roč. 95, č. 4 (2017), č. článku 042122. ISSN 2469-9926 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : operators * Hilbert space * non-Hermitian Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.925, year: 2016
Extension of the CPT theorem to non-Hermitian Hamiltonians and unstable states
Mannheim, Philip D., E-mail: philip.mannheim@uconn.edu
2016-02-10
We extend the CPT theorem to quantum field theories with non-Hermitian Hamiltonians and unstable states. Our derivation is a quite minimal one as it requires only the time-independent evolution of scalar products, invariance under complex Lorentz transformations, and a non-standard but nonetheless perfectly legitimate interpretation of charge conjugation as an antilinear operator. The first of these requirements does not force the Hamiltonian to be Hermitian. Rather, it forces its eigenvalues to either be real or to appear in complex conjugate pairs, forces the eigenvectors of such conjugate pairs to be conjugates of each other, and forces the Hamiltonian to admit of an antilinear symmetry. The latter two requirements then force this antilinear symmetry to be CPT, while forcing the Hamiltonian to be real rather than Hermitian. Our work justifies the use of the CPT theorem in establishing the equality of the lifetimes of unstable particles that are charge conjugates of each other. We show that the Euclidean time path integrals of a CPT-symmetric theory must always be real. In the quantum-mechanical limit the key results of the PT symmetry program of Bender and collaborators are recovered, with the C-operator of the PT symmetry program being identified with the linear component of the charge conjugation operator.
Pseudo-Hermitian continuous-time quantum walks
Salimi, S; Sorouri, A, E-mail: shsalimi@uok.ac.i, E-mail: a.sorouri@uok.ac.i [Department of Physics, University of Kurdistan, PO Box 66177-15175, Sanandaj (Iran, Islamic Republic of)
2010-07-09
In this paper we present a model exhibiting a new type of continuous-time quantum walk (as a quantum-mechanical transport process) on networks, which is described by a non-Hermitian Hamiltonian possessing a real spectrum. We call it pseudo-Hermitian continuous-time quantum walk. We introduce a method to obtain the probability distribution of walk on any vertex and then study a specific system. We observe that the probability distribution on certain vertices increases compared to that of the Hermitian case. This formalism makes the transport process faster and can be useful for search algorithms.
Duality property for a hermitian scalar field
Bisognano, J.J.
1975-01-01
A general hermitian scalar Wightman field is considered. On the Hilbert space of physical states ''natural'' domains for certain complex Lorentz transformations are constructed, and a theorem relating these transformations to the TCP symmetry is stated and proved. Under the additional assumption that the field is ''locally'' essentially self-adjoint, duality is considered for the algebras generated by spectral projections of smeared fields. For a class of unbounded regions duality is proved, and for certain bounded regions ''local'' extensions of the algebras are constructed which satisfy duality. The relationship of the arguments presented to the Tomita--Takesaki theory of modular Hilbert algebras is discussed. A separate analysis for the free field is also given. (auth)
Non-Hermitian systems of Euclidean Lie algebraic type with real energy spectra
Dey, Sanjib; Fring, Andreas; Mathanaranjan, Thilagarajah
2014-01-01
We study several classes of non-Hermitian Hamiltonian systems, which can be expressed in terms of bilinear combinations of Euclidean–Lie algebraic generators. The classes are distinguished by different versions of antilinear (PT)-symmetries exhibiting various types of qualitative behaviour. On the basis of explicitly computed non-perturbative Dyson maps we construct metric operators, isospectral Hermitian counterparts for which we solve the corresponding time-independent Schrödinger equation for specific choices of the coupling constants. In these cases general analytical expressions for the solutions are obtained in the form of Mathieu functions, which we analyze numerically to obtain the corresponding energy spectra. We identify regions in the parameter space for which the corresponding spectra are entirely real and also domains where the PT symmetry is spontaneously broken and sometimes also regained at exceptional points. In some cases it is shown explicitly how the threshold region from real to complex spectra is characterized by the breakdown of the Dyson maps or the metric operator. We establish the explicit relationship to models currently under investigation in the context of beam dynamics in optical lattices. -- Highlights: •Different PT-symmetries lead to qualitatively different systems. •Construction of non-perturbative Dyson maps and isospectral Hermitian counterparts. •Numerical discussion of the eigenvalue spectra for one of the E(2)-systems. •Established link to systems studied in the context of optical lattices. •Setup for the E(3)-algebra is provided
Symmetries and conservation laws in non-Hermitian field theories
Alexandre, Jean; Millington, Peter; Seynaeve, Dries
2017-09-01
Anti-Hermitian mass terms are considered, in addition to Hermitian ones, for P T -symmetric complex-scalar and fermionic field theories. In both cases, the Lagrangian can be written in a manifestly symmetric form in terms of the P T -conjugate variables, allowing for an unambiguous definition of the equations of motion. After discussing the resulting constraints on the consistency of the variational procedure, we show that the invariance of a non-Hermitian Lagrangian under a continuous symmetry transformation does not imply the existence of a corresponding conserved current. Conserved currents exist, but these are associated with transformations under which the Lagrangian is not invariant and which reflect the well-known interpretation of P T -symmetric theories in terms of systems with gain and loss. A formal understanding of this unusual feature of non-Hermitian theories requires a careful treatment of Noether's theorem, and we give specific examples for illustration.
Non-Hermitian photonics based on parity-time symmetry
Feng, Liang; El-Ganainy, Ramy; Ge, Li
2017-12-01
Nearly one century after the birth of quantum mechanics, parity-time symmetry is revolutionizing and extending quantum theories to include a unique family of non-Hermitian Hamiltonians. While conceptually striking, experimental demonstration of parity-time symmetry remains unexplored in quantum electronic systems. The flexibility of photonics allows for creating and superposing non-Hermitian eigenstates with ease using optical gain and loss, which makes it an ideal platform to explore various non-Hermitian quantum symmetry paradigms for novel device functionalities. Such explorations that employ classical photonic platforms not only deepen our understanding of fundamental quantum physics but also facilitate technological breakthroughs for photonic applications. Research into non-Hermitian photonics therefore advances and benefits both fields simultaneously.
Improved Power Decoding of One-Point Hermitian Codes
Puchinger, Sven; Bouw, Irene; Rosenkilde, Johan Sebastian Heesemann
2017-01-01
We propose a new partial decoding algorithm for one-point Hermitian codes that can decode up to the same number of errors as the Guruswami–Sudan decoder. Simulations suggest that it has a similar failure probability as the latter one. The algorithm is based on a recent generalization of the power...... decoding algorithm for Reed–Solomon codes and does not require an expensive root-finding step. In addition, it promises improvements for decoding interleaved Hermitian codes....
Modified Hermitian treatment of Dyson boson expansion theory
Kajiyama, Atsushi
2009-01-01
The Hermitian treatment of the Dyson-type boson expansion theory is reinvestigated with the aid of small-parameter expansion. A naive application of the Hermitization formula sometimes yields an unrealistic phase that spoils the conventional treatment. The complementary use of another formula having the form of the arithmetic mean can avoid that problem. This modification will improve the accuracy of the Hermitian treatment. (author)
Hermitian versus anti-hermitian one-matrix models and their hierarchies
Hollowood, T.; Miramontes, L.; Pasquinucci, A.; Nappi, C.
1992-01-01
Building on a recent work of C. Crnkovic, M. Douglas and G. Moore, a study of multi-critical multi-cut one-matrix models and their associated sl(2, C) integrable hierarchies, is further pursued. The double-scaling limits of hermitian matrix models with different scaling ansaetze, lead to the KdV hierarchy, to the modified KdV hierarchy and part of the non-linear Schroedinger hierarchy. Instead, the anti-hermitian matrix model, in the 2-arc sector, results in the Zakharov-Shabat hierarchy, which contains both KdV and mKdV as reductions. For all the hierarchies it is found that the Virasoro constraints act on the associated τ-functions. Whereas it is known that the ZS and KdV models lead to the Virasoro constraints of an sl(2, C) vacuum, we find that the mKdV model leads to the Virasoro constraints of a highest-weight state with arbitrary conformal dimension. (orig.)
The complex Laguerre symplectic ensemble of non-Hermitian matrices
Akemann, G.
2005-01-01
We solve the complex extension of the chiral Gaussian symplectic ensemble, defined as a Gaussian two-matrix model of chiral non-Hermitian quaternion real matrices. This leads to the appearance of Laguerre polynomials in the complex plane and we prove their orthogonality. Alternatively, a complex eigenvalue representation of this ensemble is given for general weight functions. All k-point correlation functions of complex eigenvalues are given in terms of the corresponding skew orthogonal polynomials in the complex plane for finite-N, where N is the matrix size or number of eigenvalues, respectively. We also allow for an arbitrary number of complex conjugate pairs of characteristic polynomials in the weight function, corresponding to massive quark flavours in applications to field theory. Explicit expressions are given in the large-N limit at both weak and strong non-Hermiticity for the weight of the Gaussian two-matrix model. This model can be mapped to the complex Dirac operator spectrum with non-vanishing chemical potential. It belongs to the symmetry class of either the adjoint representation or two colours in the fundamental representation using staggered lattice fermions
Cotangent bundles over all the Hermitian symmetric spaces
Arai, Masato; Baba, Kurando
2016-01-01
We construct the N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. In order to construct them we use the projective superspace formalism which is an N = 2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N =1 superfields, once the Kähler potentials of the base manifolds are obtained. Starting with N = 1 supersymmetric Kähler nonlinear sigma models on the Hermitian symmetric spaces, we extend them into the N = 2 supersymmetric models by using the projective superspace formalism and derive the general formula for the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. We apply to the formula for the non-compact Hermitian symmetric space E 7 /E 6 × U(1) 1 . (paper)
Non-Hermitian localization in biological networks.
Amir, Ariel; Hatano, Naomichi; Nelson, David R
2016-04-01
We explore the spectra and localization properties of the N-site banded one-dimensional non-Hermitian random matrices that arise naturally in sparse neural networks. Approximately equal numbers of random excitatory and inhibitory connections lead to spatially localized eigenfunctions and an intricate eigenvalue spectrum in the complex plane that controls the spontaneous activity and induced response. A finite fraction of the eigenvalues condense onto the real or imaginary axes. For large N, the spectrum has remarkable symmetries not only with respect to reflections across the real and imaginary axes but also with respect to 90^{∘} rotations, with an unusual anisotropic divergence in the localization length near the origin. When chains with periodic boundary conditions become directed, with a systematic directional bias superimposed on the randomness, a hole centered on the origin opens up in the density-of-states in the complex plane. All states are extended on the rim of this hole, while the localized eigenvalues outside the hole are unchanged. The bias-dependent shape of this hole tracks the bias-independent contours of constant localization length. We treat the large-N limit by a combination of direct numerical diagonalization and using transfer matrices, an approach that allows us to exploit an electrostatic analogy connecting the "charges" embodied in the eigenvalue distribution with the contours of constant localization length. We show that similar results are obtained for more realistic neural networks that obey "Dale's law" (each site is purely excitatory or inhibitory) and conclude with perturbation theory results that describe the limit of large directional bias, when all states are extended. Related problems arise in random ecological networks and in chains of artificial cells with randomly coupled gene expression patterns.
Para-Hermitian and para-quaternionic manifolds
Ivanov, S.; Zamkovoy, S.
2003-10-01
A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S 1 x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)
Hermitian self-dual quasi-abelian codes
Herbert S. Palines
2017-12-01
Full Text Available Quasi-abelian codes constitute an important class of linear codes containing theoretically and practically interesting codes such as quasi-cyclic codes, abelian codes, and cyclic codes. In particular, the sub-class consisting of 1-generator quasi-abelian codes contains large families of good codes. Based on the well-known decomposition of quasi-abelian codes, the characterization and enumeration of Hermitian self-dual quasi-abelian codes are given. In the case of 1-generator quasi-abelian codes, we offer necessary and sufficient conditions for such codes to be Hermitian self-dual and give a formula for the number of these codes. In the case where the underlying groups are some $p$-groups, the actual number of resulting Hermitian self-dual quasi-abelian codes are determined.
Para-Hermitian and para-quaternionic manifolds
Ivanov, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria) and Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Zamkovoy, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria)
2003-10-01
A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S{sup 1} x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)
A Boundary Value Problem for Hermitian Monogenic Functions
Ricardo Abreu Blaya
2008-02-01
Full Text Available We study the problem of finding a Hermitian monogenic function with a given jump on a given hypersurface in Ã¢Â„Âm,Ã¢Â€Â‰m=2n. Necessary and sufficient conditions for the solvability of this problem are obtained.
Optical Lattice Design Assisted by Non-Hermitian Hamiltonians
Rodríguez-Lara, B M
2016-01-01
A brief introduction to non-Hermitian arrays of coupled waveguides is presented. The PT-symmetric dimer is revisited for the sake of clarity. It belongs to the class of photonic lattices with underlying SO(2,1) symmetry that have been shown to provide all-optical conversion from phase to amplitude. (paper)
Non-Hermitian quantum mechanics and localization in physical systems
Hatano, Naomichi
1998-01-01
Recent studies on a delocalization phenomenon of a non-Hermitian random system is reviewed. The complex spectrum of the system indicates delocalization transition of its eigenfunctions. It is emphasized that the delocalization is related to various physical phenomena such as flux-line pinning in superconductors and population biology of bacteria colony
Computing several eigenpairs of Hermitian problems by conjugate gradient iterations
Ovtchinnikov, E.E.
2008-01-01
The paper is concerned with algorithms for computing several extreme eigenpairs of Hermitian problems based on the conjugate gradient method. We analyse computational strategies employed by various algorithms of this kind reported in the literature and identify their limitations. Our criticism is illustrated by numerical tests on a set of problems from electronic structure calculations and acoustics
Theory of non-hermitian localization in one dimension: Localization ...
of the finite depinning field H . The degree of depinning is measured by the averaged .... system [2] shows a direct relationship between the localization length of the ... tight-binding model in a non-hermitian field h, where the discrete sites n, ..... shows that complex eigenvalues do not appear for field strengths less thanh2.
Random matrix theory for pseudo-Hermitian systems: Cyclic blocks
We discuss the relevance of random matrix theory for pseudo-Hermitian systems, and, for Hamiltonians that break parity and time-reversal invariance . In an attempt to understand the random Ising model, we present the treatment of cyclic asymmetric matrices with blocks and show that the nearest-neighbour spacing ...
Random matrix theory for pseudo-Hermitian systems: Cyclic blocks
Abstract. We discuss the relevance of random matrix theory for pseudo-Hermitian sys- tems, and, for Hamiltonians that break parity P and time-reversal invariance T. In an attempt to understand the random Ising model, we present the treatment of cyclic asym- metric matrices with blocks and show that the nearest-neighbour ...
Non-Hermitian systems of Euclidean Lie algebraic type with real energy spectra
Dey, Sanjib; Fring, Andreas; Mathanaranjan, Thilagarajah
2014-07-01
We study several classes of non-Hermitian Hamiltonian systems, which can be expressed in terms of bilinear combinations of Euclidean-Lie algebraic generators. The classes are distinguished by different versions of antilinear (PT)-symmetries exhibiting various types of qualitative behaviour. On the basis of explicitly computed non-perturbative Dyson maps we construct metric operators, isospectral Hermitian counterparts for which we solve the corresponding time-independent Schrödinger equation for specific choices of the coupling constants. In these cases general analytical expressions for the solutions are obtained in the form of Mathieu functions, which we analyze numerically to obtain the corresponding energy spectra. We identify regions in the parameter space for which the corresponding spectra are entirely real and also domains where the PT symmetry is spontaneously broken and sometimes also regained at exceptional points. In some cases it is shown explicitly how the threshold region from real to complex spectra is characterized by the breakdown of the Dyson maps or the metric operator. We establish the explicit relationship to models currently under investigation in the context of beam dynamics in optical lattices.
Some spectral equivalences between Schroedinger operators
Dunning, C; Hibberd, K E; Links, J
2008-01-01
Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schroedinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators
Higher genus correlators from the hermitian one-matrix model
Ambjoern, J.; Chekhov, L.; Makeenko, Yu.
1992-01-01
We develop an iterative algorithm for the genus expansion of the hermitian NxN one-matrix model (is the Penner model in an external field). By introducing moments of the external field, we prove that the genus g contribution to the m-loop correlator depends only on 3g-2+m lower moments (3g-2 for the partition function). We present the explicit results for the partition function and the one-loop correlator in genus one. We compare the correlators for the hermitian one-matrix model with those at zero momenta for c=1 CFT and show an agreement of the one-loop correlators for genus zero. (orig.)
Exact 2-point function in Hermitian matrix model
Morozov, A.; Shakirov, Sh.
2009-01-01
J. Harer and D. Zagier have found a strikingly simple generating function [1,2] for exact (all-genera) 1-point correlators in the Gaussian Hermitian matrix model. In this paper we generalize their result to 2-point correlators, using Toda integrability of the model. Remarkably, this exact 2-point correlation function turns out to be an elementary function - arctangent. Relation to the standard 2-point resolvents is pointed out. Some attempts of generalization to 3-point and higher functions are described.
Non-Hermitian Extensions of Wishart Random Matrix Ensembles
Akemann, G.
2011-01-01
We briefly review the solution of three ensembles of non-Hermitian random matrices generalizing the Wishart-Laguerre (also called chiral) ensembles. These generalizations are realized as Gaussian two-matrix models, where the complex eigenvalues of the product of the two independent rectangular matrices are sought, with the matrix elements of both matrices being either real, complex or quaternion real. We also present the more general case depending on a non-Hermiticity parameter, that allows us to interpolate between the corresponding three Hermitian Wishart ensembles with real eigenvalues and the maximally non-Hermitian case. All three symmetry classes are explicitly solved for finite matrix size N x M for all complex eigenvalue correlations functions (and real or mixed correlations for real matrix elements). These are given in terms of the corresponding kernels built from orthogonal or skew-orthogonal Laguerre polynomials in the complex plane. We then present the corresponding three Bessel kernels in the complex plane in the microscopic large-N scaling limit at the origin, both at weak and strong non-Hermiticity with M - N ≥ 0 fixed. (author)
Hermitian Mindlin Plate Wavelet Finite Element Method for Load Identification
Xiaofeng Xue
2016-01-01
Full Text Available A new Hermitian Mindlin plate wavelet element is proposed. The two-dimensional Hermitian cubic spline interpolation wavelet is substituted into finite element functions to construct frequency response function (FRF. It uses a system’s FRF and response spectrums to calculate load spectrums and then derives loads in the time domain via the inverse fast Fourier transform. By simulating different excitation cases, Hermitian cubic spline wavelets on the interval (HCSWI finite elements are used to reverse load identification in the Mindlin plate. The singular value decomposition (SVD method is adopted to solve the ill-posed inverse problem. Compared with ANSYS results, HCSWI Mindlin plate element can accurately identify the applied load. Numerical results show that the algorithm of HCSWI Mindlin plate element is effective. The accuracy of HCSWI can be verified by comparing the FRF of HCSWI and ANSYS elements with the experiment data. The experiment proves that the load identification of HCSWI Mindlin plate is effective and precise by using the FRF and response spectrums to calculate the loads.
Moyal products-a new perspective on quasi-Hermitian quantum mechanics
Scholtz, F G; Geyer, H B
2006-01-01
The rationale for introducing non-Hermitian Hamiltonians and other observables is reviewed and open issues identified. We present a new approach based on Moyal products to compute the metric for quasi-Hermitian systems. This approach is not only an efficient method of computation, but also suggests a new perspective on quasi-Hermitian quantum mechanics which invites further exploration. In particular, we present some first results which link the Berry connection and curvature to non-perturbative properties and the metric
Numerical solution to the hermitian Yang-Mills equation on the Fermat quintic
Douglas, Michael R.; Karp, Robert L.; Lukic, Sergio; Reinbacher, Rene
2007-01-01
We develop an iterative method for finding solutions to the hermitian Yang-Mills equation on stable holomorphic vector bundles, following ideas recently developed by Donaldson. As illustrations, we construct numerically the hermitian Einstein metrics on the tangent bundle and a rank three vector bundle on P 2 . In addition, we find a hermitian Yang-Mills connection on a stable rank three vector bundle on the Fermat quintic
Ghatak, Ananya; Das, Tanmoy
2018-01-01
Recently developed parity (P ) and time-reversal (T ) symmetric non-Hermitian systems govern a rich variety of new and characteristically distinct physical properties, which may or may not have a direct analog in their Hermitian counterparts. We study here a non-Hermitian, PT -symmetric superconducting Hamiltonian that possesses a real quasiparticle spectrum in the PT -unbroken region of the Brillouin zone. Within a single-band mean-field theory, we find that real quasiparticle energies are possible when the superconducting order parameter itself is either Hermitian or anti-Hermitian. Within the corresponding Bardeen-Cooper-Schrieffer (BCS) theory, we find that several properties are characteristically distinct and novel in the non-Hermitian pairing case than its Hermitian counterpart. One of our significant findings is that while a Hermitian superconductor gives a second-order phase transition, the non-Hermitian one produces a robust first-order phase transition. The corresponding thermodynamic properties and the Meissner effect are also modified accordingly. Finally, we discuss how such a PT -symmetric pairing can emerge from an antisymmetric potential, such as the Dzyloshinskii-Moriya interaction, but with an external bath, or complex potential, among others.
Pseudospectra in non-Hermitian quantum mechanics
Krejčiřík, David; Siegl, Petr; Tater, Miloš; Viola, J.
2015-01-01
Roč. 56, č. 10 (2015), s. 103513 ISSN 0022-2488 R&D Projects: GA ČR(CZ) GA14-06818S; GA MŠk 7AMB12FR020 Institutional support: RVO:61389005 Keywords : quadratic differential operators * magnetic field Subject RIV: BE - Theoretical Physics Impact factor: 1.234, year: 2015
Cheng, Yi-Xin
1992-01-01
The Schwinger-Dyson loop equations for the hermitian multi-matrix chain models at finite N, are derived from the Ward identities of the partition functional under the infinitesimal field transformations. The constraint operators W n (m) satisfy the w 1+∞ -like algebra up to a linear combination of the lower spin operators. We find that the all the higher spin constraints are reducible to the Virasoro-type constraints for all the matrix chain models. (author)
Vecharynski, Eugene; Yang, Chao; Pask, John E.
2015-01-01
We present an iterative algorithm for computing an invariant subspace associated with the algebraically smallest eigenvalues of a large sparse or structured Hermitian matrix A. We are interested in the case in which the dimension of the invariant subspace is large (e.g., over several hundreds or thousands) even though it may still be small relative to the dimension of A. These problems arise from, for example, density functional theory (DFT) based electronic structure calculations for complex materials. The key feature of our algorithm is that it performs fewer Rayleigh–Ritz calculations compared to existing algorithms such as the locally optimal block preconditioned conjugate gradient or the Davidson algorithm. It is a block algorithm, and hence can take advantage of efficient BLAS3 operations and be implemented with multiple levels of concurrency. We discuss a number of practical issues that must be addressed in order to implement the algorithm efficiently on a high performance computer
Analytical results for non-Hermitian parity–time-symmetric and ...
Abstract. We investigate both the non-Hermitian parity–time-(PT-)symmetric and Hermitian asymmetric volcano potentials, and present the analytical solution in terms of the confluent Heun function. Under certain special conditions, the confluent Heun function can be terminated as a polynomial, thereby leading to certain ...
20th International Workshop on Hermitian Symmetric Spaces and Submanifolds
Ohnita, Yoshihiro; Zhou, Jiazu; Kim, Byung; Lee, Hyunjin
2017-01-01
This book presents the proceedings of the 20th International Workshop on Hermitian Symmetric Spaces and Submanifolds, which was held at the Kyungpook National University from June 21 to 25, 2016. The Workshop was supported by the Research Institute of Real and Complex Manifolds (RIRCM) and the National Research Foundation of Korea (NRF). The Organizing Committee invited 30 active geometers of differential geometry and related fields from all around the globe to discuss new developments for research in the area. These proceedings provide a detailed overview of recent topics in the field of real and complex submanifolds.
Correlation functions for Hermitian many-body systems: Necessary conditions
Brown, E.B.
1994-01-01
Lee [Phys. Rev. B 47, 8293 (1993)] has shown that the odd-numbered derivatives of the Kubo autocorrelation function vanish at t=0. We show that this condition is based on a more general property of nondiagonal Kubo correlation functions. This general property provides that certain functional forms (e.g., simple exponential decay) are not admissible for any symmetric or antisymmetric Kubo correlation function in a Hermitian many-body system. Lee's result emerges as a special case of this result. Applications to translationally invariant systems and systems with rotational symmetries are also demonstrated
Sub-quadratic decoding of one-point hermitian codes
Nielsen, Johan Sebastian Rosenkilde; Beelen, Peter
2015-01-01
We present the first two sub-quadratic complexity decoding algorithms for one-point Hermitian codes. The first is based on a fast realization of the Guruswami-Sudan algorithm using state-of-the-art algorithms from computer algebra for polynomial-ring matrix minimization. The second is a power...... decoding algorithm: an extension of classical key equation decoding which gives a probabilistic decoding algorithm up to the Sudan radius. We show how the resulting key equations can be solved by the matrix minimization algorithms from computer algebra, yielding similar asymptotic complexities....
Factorisations for partition functions of random Hermitian matrix models
Jackson, D.M.; Visentin, T.I.
1996-01-01
The partition function Z N , for Hermitian-complex matrix models can be expressed as an explicit integral over R N , where N is a positive integer. Such an integral also occurs in connection with random surfaces and models of two dimensional quantum gravity. We show that Z N can be expressed as the product of two partition functions, evaluated at translated arguments, for another model, giving an explicit connection between the two models. We also give an alternative computation of the partition function for the φ 4 -model.The approach is an algebraic one and holds for the functions regarded as formal power series in the appropriate ring. (orig.)
Hermitian-Einstein metrics on parabolic stable bundles
Li Jiayu; Narasimhan, M.S.
1995-12-01
Let M-bar be a compact complex manifold of complex dimension two with a smooth Kaehler metric and D a smooth divisor on M-bar. If E is a rank 2 holomorphic vector bundle on M-bar with a stable parabolic structure along D, we prove the existence of a metric on E' = E module MbarD (compatible with the parabolic structure) which is Hermitian-Einstein with respect to the restriction of Kaehler metric of M-barD. A converse is also proved. (author). 24 refs
Piecewise adiabatic following in non-Hermitian cycling
Gong, Jiangbin; Wang, Qing-hai
2018-05-01
The time evolution of periodically driven non-Hermitian systems is in general nonunitary but can be stable. It is hence of considerable interest to examine the adiabatic following dynamics in periodically driven non-Hermitian systems. We show in this work the possibility of piecewise adiabatic following interrupted by hopping between instantaneous system eigenstates. This phenomenon is first observed in a computational model and then theoretically explained, using an exactly solvable model, in terms of the Stokes phenomenon. In the latter case, the piecewise adiabatic following is shown to be a genuine critical behavior and the precise phase boundary in the parameter space is located. Interestingly, the critical boundary for piecewise adiabatic following is found to be unrelated to the domain for exceptional points. To characterize the adiabatic following dynamics, we also advocate a simple definition of the Aharonov-Anandan (AA) phase for nonunitary cyclic dynamics, which always yields real AA phases. In the slow driving limit, the AA phase reduces to the Berry phase if adiabatic following persists throughout the driving without hopping, but oscillates violently and does not approach any limit in cases of piecewise adiabatic following. This work exposes the rich features of nonunitary dynamics in cases of slow cycling and should stimulate future applications of nonunitary dynamics.
Self-hybridization within non-Hermitian localized plasmonic systems
Lourenço-Martins, Hugo; Das, Pabitra; Tizei, Luiz H. G.; Weil, Raphaël; Kociak, Mathieu
2018-04-01
The orthogonal eigenmodes are well-defined solutions of Hermitian equations describing many physical situations from quantum mechanics to acoustics. However, a large variety of non-Hermitian problems, including gravitational waves close to black holes or leaky electromagnetic cavities, require the use of a bi-orthogonal eigenbasis with consequences challenging our physical understanding1-4. The need to compensate for energy losses made the few successful attempts5-8 to experimentally probe non-Hermiticity extremely complicated. We overcome this problem by considering localized plasmonic systems. As the non-Hermiticity in these systems does not stem from temporal invariance breaking but from spatial symmetry breaking, its consequences can be observed more easily. We report on the theoretical and experimental evidence for non-Hermiticity-induced strong coupling between surface plasmon modes of different orders within silver nanodaggers. The symmetry conditions for triggering this counter-intuitive self-hybridization phenomenon are provided. Similar observable effects are expected to exist in any system exhibiting bi-orthogonal eigenmodes.
Multiple Meixner polynomials and non-Hermitian oscillator Hamiltonians
Ndayiragije, F; Van Assche, W
2013-01-01
Multiple Meixner polynomials are polynomials in one variable which satisfy orthogonality relations with respect to r > 1 different negative binomial distributions (Pascal distributions). There are two kinds of multiple Meixner polynomials, depending on the selection of the parameters in the negative binomial distribution. We recall their definition and some formulas and give generating functions and explicit expressions for the coefficients in the nearest neighbor recurrence relation. Following a recent construction of Miki, Tsujimoto, Vinet and Zhedanov (for multiple Meixner polynomials of the first kind), we construct r > 1 non-Hermitian oscillator Hamiltonians in r dimensions which are simultaneously diagonalizable and for which the common eigenstates are expressed in terms of multiple Meixner polynomials of the second kind. (paper)
Kullig, Julius; Wiersig, Jan
2016-01-01
In optical microdisk cavities with boundary deformations the backscattering between clockwise and counter-clockwise propagating waves is in general asymmetric. The striking consequence of this asymmetry is that these apparently weakly open systems show pronounced non-Hermitian phenomena. The optical modes appear in non-orthogonal pairs, where both modes copropagate in a preferred sense of rotation, i.e. the modes exhibit a finite chirality. Full asymmetry in the backscattering results in a non-Hermitian degeneracy (exceptional point) where the deviation from closed system evolution is strongest. We study the effects of asymmetric backscattering in ray dynamics. For this purpose, we construct a finite approximation of the Frobenius–Perron operator for deformed microdisk cavities, which describes the dynamics of intensities in phase space. Eigenstates of the Frobenius–Perron operator show nice analogies to optical modes: they come in non-orthogonal copropagating pairs and have a finite chirality. We introduce a new cavity system with a smooth asymmetric boundary deformation where we demonstrate our results and we illustrate the main aspects with the help of a simple analytically solvable 1D model. (paper)
Spontaneous symmetry breaking and the Goldstone theorem in non-Hermitian field theories arXiv
Alexandre, Jean; Millington, Peter; Seynaeve, Dries
We demonstrate the extension to PT-symmetric field theories of the Goldstone theorem, confirming that the spontaneous appearance of a field vacuum expectation value via minimisation of the effective potential in a non-Hermitian model is accompanied by a massless scalar boson. Laying a basis for our analysis, we first show how the conventional quantisation of the path-integral formulation of quantum field theory can be extended consistently to a non-Hermitian model by considering PT conjugation instead of Hermitian conjugation. The extension of the Goldstone theorem to a PT-symmetric field theory is made possible by the existence of a conserved current that does not, however, correspond to a symmetry of the non-Hermitian Lagrangian. In addition to extending the proof of the Goldstone theorem to a PT-symmetric theory, we exhibit a specific example in which we verify the existence of a massless boson at the tree and one-loop levels.
A rule of the equilibrium of forces in the Hermitian theory of relativity
Antoci, S.
1987-01-01
When the behaviour of the singularities, which are used to represent masses, charges or currents in exact solutions to the field equations of the Hermitian theory of relativity, is restricted by a no-jump rule, conditions are obtained, which determine the relative positions of masses, charges and currents. Due to these conditions the Hermitian theory of relativity appears to provide a unified description of gravitational, colour and electromagnetic forces. (author)
Infinite families of (non)-Hermitian Hamiltonians associated with exceptional Xm Jacobi polynomials
Midya, Bikashkali; Roy, Barnana
2013-01-01
Using an appropriate change of variable, the Schrödinger equation is transformed into a second-order differential equation satisfied by recently discovered Jacobi-type X m exceptional orthogonal polynomials. This facilitates the derivation of infinite families of exactly solvable Hermitian as well as non-Hermitian trigonometric Scarf potentials and a finite number of Hermitian and an infinite number of non-Hermitian PT-symmetric hyperbolic Scarf potentials. The bound state solutions of all these potentials are associated with the aforesaid exceptional orthogonal polynomials. These infinite families of potentials are shown to be extensions of the conventional trigonometric and hyperbolic Scarf potentials by the addition of some rational terms characterized by the presence of classical Jacobi polynomials. All the members of a particular family of these ‘rationally extended polynomial-dependent’ potentials have the same energy spectrum and possess translational shape-invariant symmetry. The obtained non-Hermitian trigonometric Scarf potentials are shown to be quasi-Hermitian in nature ensuring the reality of the associated energy spectra. (paper)
Metric versus observable operator representation, higher spin models
Fring, Andreas; Frith, Thomas
2018-02-01
We elaborate further on the metric representation that is obtained by transferring the time-dependence from a Hermitian Hamiltonian to the metric operator in a related non-Hermitian system. We provide further insight into the procedure on how to employ the time-dependent Dyson relation and the quasi-Hermiticity relation to solve time-dependent Hermitian Hamiltonian systems. By solving both equations separately we argue here that it is in general easier to solve the former. We solve the mutually related time-dependent Schrödinger equation for a Hermitian and non-Hermitian spin 1/2, 1 and 3/2 model with time-independent and time-dependent metric, respectively. In all models the overdetermined coupled system of equations for the Dyson map can be decoupled algebraic manipulations and reduces to simple linear differential equations and an equation that can be converted into the non-linear Ermakov-Pinney equation.
Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting.
Kim, Soo Jin; Kang, Ju-Hyung; Mutlu, Mehmet; Park, Joonsuk; Park, Woosung; Goodson, Kenneth E; Sinclair, Robert; Fan, Shanhui; Kik, Pieter G; Brongersma, Mark L
2018-01-22
The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons.
Savin, Dmitry V.; Sokolov, Valentin V.; Sommers, Hans-Juergen
2003-01-01
We examine the notion and properties of the non-Hermitian effective Hamiltonian of an unstable system using as an example potential resonance scattering with a fixed angular momentum. We present a consistent self-adjoint formulation of the problem of scattering on a finite-range potential, which is based on the separation of the configuration space into two segments, internal and external. The scattering amplitude is expressed in terms of the resolvent of a non-Hermitian operator H. The explicit form of this operator depends on both the radius of separation and the boundary conditions at this place, which can be chosen in many different ways. We discuss this freedom and show explicitly that the physical scattering amplitude is, nevertheless, unique, although not all choices are equally adequate from the physical point of view. The energy-dependent operator H should not be confused with the non-Hermitian effective Hamiltonian H eff which is usually exploited to describe interference of overlapping resonances. We note that the simple Breit-Wigner approximation is as a rule valid for any individual resonance in the case of few-channel scattering on a flat billiardlike cavity, leaving no room for nontrivial H eff to appear. The physics is appreciably richer in the case of an open chain of L connected similar cavities whose spectrum has a band structure. For a fixed band of L overlapping resonances, the smooth energy dependence of H can be ignored so that the constant LxL submatrix H eff approximately describes the time evolution of the chain in the energy domain of the band and the complex eigenvalues of H eff define the energies and widths of the resonances. We apply the developed formalism to the problem of a chain of L δ barriers, whose solution is also found independently in a closed form. We construct H eff for the two commonly considered types of boundary conditions (Neumann and Dirichlet) for the internal motion. Although the final results are in perfect
Fock model and Segal-Bargmann transform for minimal representations of Hermitian Lie groups
Hilgert, Joachim; Kobayashi, Toshiyuki; Möllers, Jan
2012-01-01
For any Hermitian Lie group G of tube type we construct a Fock model of its minimal representation. The Fock space is defined on the minimal nilpotent K_C-orbit X in p_C and the L^2-inner product involves a K-Bessel function as density. Here K is a maximal compact subgroup of G, and g......_C=k_C+p_C is a complexified Cartan decomposition. In this realization the space of k-finite vectors consists of holomorphic polynomials on X. The reproducing kernel of the Fock space is calculated explicitly in terms of an I-Bessel function. We further find an explicit formula of a generalized Segal-Bargmann transform which...... intertwines the Schroedinger and Fock model. Its kernel involves the same I-Bessel function. Using the Segal--Bargmann transform we also determine the integral kernel of the unitary inversion operator in the Schroedinger model which is given by a J-Bessel function....
Constant-intensity waves and their modulation instability in non-Hermitian potentials
Makris, K. G.; Musslimani, Z. H.; Christodoulides, D. N.; Rotter, S.
2015-07-01
In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.
Geometry of quantal adiabatic evolution driven by a non-Hermitian Hamiltonian
Wu Zhaoyan; Yu Ting; Zhou Hongwei
1994-01-01
It is shown by using a counter example, which is exactly solvable, that the quantal adiabatic theorem does not generally hold for a non-Hermitian driving Hamiltonian, even if it varies extremely slowly. The condition for the quantal adiabatic theorem to hold for non-Hermitian driving Hamiltonians is given. The adiabatic evolutions driven by a non-Hermitian Hamiltonian provide examples of a new geometric structure, that is the vector bundle in which the inner product of two parallelly transported vectors generally changes. A new geometric concept, the attenuation tensor, is naturally introduced to describe the decay or flourish of the open quantum system. It is constructed in terms of the spectral projector of the Hamiltonian. (orig.)
Higher genus correlators for the hermitian matrix model with multiple cuts
Akemann, G.
1996-01-01
An iterative scheme is set up for solving the loop equation of the hermitian one-matrix model with a multi-cut structure. Explicit results are presented for genus one for an arbitrary but finite number of cuts. Due to the complicated form of the boundary conditions, the loop correlators now contain elliptic integrals. This demonstrates the existence of new universality classes for the hermitian matrix model. The two-cut solution is investigated in more detail, including the double scaling limit. It is shown that in special cases it differs from the known continuum solution with one cut. (orig.)
Resolutions of Identity for Some Non-Hermitian Hamiltonians. II. Proofs
Andrey V. Sokolov
2011-12-01
Full Text Available This part is a continuation of the Part I where we built resolutions of identity for certain non-Hermitian Hamiltonians constructed of biorthogonal sets of their eigen- and associated functions for the spectral problem defined on entire axis. Non-Hermitian Hamiltonians under consideration are taken with continuous spectrum and the following cases are examined: an exceptional point of arbitrary multiplicity situated on a boundary of continuous spectrum and an exceptional point situated inside of continuous spectrum. In the present work the rigorous proofs are given for the resolutions of identity in both cases.
An integral conservative gridding--algorithm using Hermitian curve interpolation.
Volken, Werner; Frei, Daniel; Manser, Peter; Mini, Roberto; Born, Ernst J; Fix, Michael K
2008-11-07
The problem of re-sampling spatially distributed data organized into regular or irregular grids to finer or coarser resolution is a common task in data processing. This procedure is known as 'gridding' or 're-binning'. Depending on the quantity the data represents, the gridding-algorithm has to meet different requirements. For example, histogrammed physical quantities such as mass or energy have to be re-binned in order to conserve the overall integral. Moreover, if the quantity is positive definite, negative sampling values should be avoided. The gridding process requires a re-distribution of the original data set to a user-requested grid according to a distribution function. The distribution function can be determined on the basis of the given data by interpolation methods. In general, accurate interpolation with respect to multiple boundary conditions of heavily fluctuating data requires polynomial interpolation functions of second or even higher order. However, this may result in unrealistic deviations (overshoots or undershoots) of the interpolation function from the data. Accordingly, the re-sampled data may overestimate or underestimate the given data by a significant amount. The gridding-algorithm presented in this work was developed in order to overcome these problems. Instead of a straightforward interpolation of the given data using high-order polynomials, a parametrized Hermitian interpolation curve was used to approximate the integrated data set. A single parameter is determined by which the user can control the behavior of the interpolation function, i.e. the amount of overshoot and undershoot. Furthermore, it is shown how the algorithm can be extended to multidimensional grids. The algorithm was compared to commonly used gridding-algorithms using linear and cubic interpolation functions. It is shown that such interpolation functions may overestimate or underestimate the source data by about 10-20%, while the new algorithm can be tuned to
An integral conservative gridding-algorithm using Hermitian curve interpolation
Volken, Werner; Frei, Daniel; Manser, Peter; Mini, Roberto; Born, Ernst J; Fix, Michael K
2008-01-01
The problem of re-sampling spatially distributed data organized into regular or irregular grids to finer or coarser resolution is a common task in data processing. This procedure is known as 'gridding' or 're-binning'. Depending on the quantity the data represents, the gridding-algorithm has to meet different requirements. For example, histogrammed physical quantities such as mass or energy have to be re-binned in order to conserve the overall integral. Moreover, if the quantity is positive definite, negative sampling values should be avoided. The gridding process requires a re-distribution of the original data set to a user-requested grid according to a distribution function. The distribution function can be determined on the basis of the given data by interpolation methods. In general, accurate interpolation with respect to multiple boundary conditions of heavily fluctuating data requires polynomial interpolation functions of second or even higher order. However, this may result in unrealistic deviations (overshoots or undershoots) of the interpolation function from the data. Accordingly, the re-sampled data may overestimate or underestimate the given data by a significant amount. The gridding-algorithm presented in this work was developed in order to overcome these problems. Instead of a straightforward interpolation of the given data using high-order polynomials, a parametrized Hermitian interpolation curve was used to approximate the integrated data set. A single parameter is determined by which the user can control the behavior of the interpolation function, i.e. the amount of overshoot and undershoot. Furthermore, it is shown how the algorithm can be extended to multidimensional grids. The algorithm was compared to commonly used gridding-algorithms using linear and cubic interpolation functions. It is shown that such interpolation functions may overestimate or underestimate the source data by about 10-20%, while the new algorithm can be tuned to
Photonic Band Structure of Dispersive Metamaterials Formulated as a Hermitian Eigenvalue Problem
Raman, Aaswath; Fan, Shanhui
2010-01-01
We formulate the photonic band structure calculation of any lossless dispersive photonic crystal and optical metamaterial as a Hermitian eigenvalue problem. We further show that the eigenmodes of such lossless systems provide an orthonormal basis, which can be used to rigorously describe the behavior of lossy dispersive systems in general. © 2010 The American Physical Society.
Astrophysical evidence for the non-Hermitian but PT-symmetric Hamiltonian of conformal gravity
Mannheim, P.D.
2013-01-01
In this review we discuss the connection between two seemingly disparate topics, macroscopic gravity on astrophysical scales and Hamiltonians that are not Hermitian but PT symmetric on microscopic ones. In particular we show that the quantum-mechanical unitarity problem of the fourth-order derivative conformal gravity theory is resolved by recognizing that the scalar product appropriate to the theory is not the Dirac norm associated with a Hermitian Hamiltonian but is instead the norm associated with a non-Hermitian but PT-symmetric Hamiltonian. Moreover, the fourth-order theory Hamiltonian is not only not Hermitian, it is not even diagonalizable, being of Jordan-block form. With PT symmetry we establish that conformal gravity is consistent at the quantum-mechanical level. In consequence, we can apply the theory to data, to find that the theory is capable of naturally accounting for the systematics of the rotation curves of a large and varied sample of 138 spiral galaxies without any need for dark matter. The success of the fits provides evidence for the relevance of non-diagonalizable but PT-symmetric Hamiltonians to physics. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Photonic Band Structure of Dispersive Metamaterials Formulated as a Hermitian Eigenvalue Problem
Raman, Aaswath
2010-02-26
We formulate the photonic band structure calculation of any lossless dispersive photonic crystal and optical metamaterial as a Hermitian eigenvalue problem. We further show that the eigenmodes of such lossless systems provide an orthonormal basis, which can be used to rigorously describe the behavior of lossy dispersive systems in general. © 2010 The American Physical Society.
Supersymmetry and cotangent bundle over non-compact exceptional Hermitian symmetric space
Arai, Masato; Baba, Kurando
2015-01-01
We construct N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the non-compact exceptional Hermitian symmetric spaces M=E 6(−14) /SO(10)×U(1) and E 7(−25) /E 6 ×U(1). In order to construct them we use the projective superspace formalism which is an N=2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N=2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N=1 superfields, once the Kähler potentials of the base manifolds are obtained. We derive the N=1 supersymmetric nonlinear sigma models on the Kähler manifolds M. Then we extend them into the N=2 supersymmetric models with the use of the result in arXiv:1211.1537 developed in the projective superspace formalism. The resultant models are the N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the Hermitian symmetric spaces M. In this work we complete constructing the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces.
2 × 2 random matrix ensembles with reduced symmetry: from Hermitian to PT -symmetric matrices
Gong Jiangbin; Wang Qinghai
2012-01-01
A possibly fruitful extension of conventional random matrix ensembles is proposed by imposing symmetry constraints on conventional Hermitian matrices or parity–time (PT)-symmetric matrices. To illustrate the main idea, we first study 2 × 2 complex Hermitian matrix ensembles with O(2)-invariant constraints, yielding novel level-spacing statistics such as singular distributions, the half-Gaussian distribution, distributions interpolating between the GOE (Gaussian orthogonal ensemble) distribution and half-Gaussian distributions, as well as the gapped-GOE distribution. Such a symmetry-reduction strategy is then used to explore 2 × 2 PT-symmetric matrix ensembles with real eigenvalues. In particular, PT-symmetric random matrix ensembles with U(2) invariance can be constructed, with the conventional complex Hermitian random matrix ensemble being a special case. In two examples of PT-symmetric random matrix ensembles, the level-spacing distributions are found to be the standard GUE (Gaussian unitary ensemble) statistics or the ‘truncated-GUE’ statistics. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)
Krylov Subspace Methods for Complex Non-Hermitian Linear Systems. Thesis
Freund, Roland W.
1991-01-01
We consider Krylov subspace methods for the solution of large sparse linear systems Ax = b with complex non-Hermitian coefficient matrices. Such linear systems arise in important applications, such as inverse scattering, numerical solution of time-dependent Schrodinger equations, underwater acoustics, eddy current computations, numerical computations in quantum chromodynamics, and numerical conformal mapping. Typically, the resulting coefficient matrices A exhibit special structures, such as complex symmetry, or they are shifted Hermitian matrices. In this paper, we first describe a Krylov subspace approach with iterates defined by a quasi-minimal residual property, the QMR method, for solving general complex non-Hermitian linear systems. Then, we study special Krylov subspace methods designed for the two families of complex symmetric respectively shifted Hermitian linear systems. We also include some results concerning the obvious approach to general complex linear systems by solving equivalent real linear systems for the real and imaginary parts of x. Finally, numerical experiments for linear systems arising from the complex Helmholtz equation are reported.
Large-N limit of the two-Hermitian-matrix model by the hidden BRST method
Alfaro, J.
1993-01-01
This paper discusses the large-N limit of the two-Hermitian-matrix model in zero dimensions, using the hidden Becchi-Rouet-Stora-Tyutin method. A system of integral equations previously found is solved, showing that it contained the exact solution of the model in leading order of large N
Non-Hermitian Hamiltonians with a real spectrum and their physical ...
We present an evaluation of some recent attempts to understand the role of pseudo-Hermitian and P T -symmetric Hamiltonians in modelling unitary quantum systems and elaborate on a particular physical phenomenon whose discovery originated in the study of complex scattering potentials.
Yi, Xingwen; Chen, Xuemei; Sharma, Dinesh; Li, Chao; Luo, Ming; Yang, Qi; Li, Zhaohui; Qiu, Kun
2014-06-02
Digital coherent superposition (DCS) provides an approach to combat fiber nonlinearities by trading off the spectrum efficiency. In analogy, we extend the concept of DCS to the optical OFDM subcarrier pairs with Hermitian symmetry to combat the linear and nonlinear phase noise. At the transmitter, we simply use a real-valued OFDM signal to drive a Mach-Zehnder (MZ) intensity modulator biased at the null point and the so-generated OFDM signal is Hermitian in the frequency domain. At receiver, after the conventional OFDM signal processing, we conduct DCS of the optical OFDM subcarrier pairs, which requires only conjugation and summation. We show that the inter-carrier-interference (ICI) due to phase noise can be reduced because of the Hermitain symmetry. In a simulation, this method improves the tolerance to the laser phase noise. In a nonlinear WDM transmission experiment, this method also achieves better performance under the influence of cross phase modulation (XPM).
Defect States Emerging from a Non-Hermitian Flatband of Photonic Zero Modes
Qi, Bingkun; Zhang, Lingxuan; Ge, Li
2018-03-01
We show the existence of a flatband consisting of photonic zero modes in a gain and loss modulated lattice system as a result of the underlying non-Hermitian particle-hole symmetry. This general finding explains the previous observation in parity-time symmetric systems where non-Hermitian particle-hole symmetry is hidden. We further discuss the defect states in these systems, whose emergence can be viewed as an unconventional alignment of a pseudospin under the influence of a complex-valued pseudomagnetic field. These defect states also behave as a chain with two types of links, one rigid in a unit cell and one soft between unit cells, as the defect states become increasingly localized with the gain and loss strength.
The Optimization on Ranks and Inertias of a Quadratic Hermitian Matrix Function and Its Applications
Yirong Yao
2013-01-01
Full Text Available We solve optimization problems on the ranks and inertias of the quadratic Hermitian matrix function subject to a consistent system of matrix equations and . As applications, we derive necessary and sufficient conditions for the solvability to the systems of matrix equations and matrix inequalities , and in the Löwner partial ordering to be feasible, respectively. The findings of this paper widely extend the known results in the literature.
Superradiance, disorder, and the non-Hermitian Hamiltonian in open quantum systems
Celardo, G. L.; Biella, A.; Giusteri, G. G.; Mattiotti, F. [Dipartimento di Matematica e Fisica and Interdisciplinary Laboratories for Advanced Materials Physics, Università Cattolica, via Musei 41, 25121 Brescia (Italy); Zhang, Y.; Kaplan, L. [Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118 (United States)
2014-10-15
We first briefly review the non-Hermitian effective Hamiltonian approach to open quantum systems and the associated phenomenon of superradiance. We next discuss the superradiance crossover in the presence of disorder and the relationship between superradiance and the localization transition. Finally, we investigate the regime of validity of the energy-independent effective Hamiltonian approximation and show that the results obtained by these methods are applicable to realistic physical systems.
Hjalmar Rosengren
2006-12-01
Full Text Available We study multivariable Christoffel-Darboux kernels, which may be viewed as reproducing kernels for antisymmetric orthogonal polynomials, and also as correlation functions for products of characteristic polynomials of random Hermitian matrices. Using their interpretation as reproducing kernels, we obtain simple proofs of Pfaffian and determinant formulas, as well as Schur polynomial expansions, for such kernels. In subsequent work, these results are applied in combinatorics (enumeration of marked shifted tableaux and number theory (representation of integers as sums of squares.
Various scattering properties of a new PT-symmetric non-Hermitian potential
Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Mandal, Raka Dona Ray, E-mail: rakad.ray@gmail.com [Department of Physics, Rajghat Besant School, Varanasi-221001 (India); Mandal, Bhabani Prasad, E-mail: bhabani.mandal@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India)
2013-09-15
We complexify a 1-d potential V(x)=V{sub 0}cosh{sup 2}μ(tanh[(x−μd)/d]+tanh(μ)){sup 2} which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system.
Various scattering properties of a new PT-symmetric non-Hermitian potential
Ghatak, Ananya; Mandal, Raka Dona Ray; Mandal, Bhabani Prasad
2013-01-01
We complexify a 1-d potential V(x)=V 0 cosh 2 μ(tanh[(x−μd)/d]+tanh(μ)) 2 which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system
A note on Hermitian-Einstein metrics on parabolic stable bundles
Li Jiayu; Narasimhan, M.S.
2000-01-01
Let M-bar be a compact complex manifold of complex dimension two with a smooth Kaehler metric and D a smooth divisor on M-bar. If E is a rank 2 holomorphic vector bundle on M-bar with a stable parabolic structure along D, we prove that there exists a Hermitian-Einstein metric on E' = E-vertical bar M-barbackslashD compatible with the parabolic structure, and whose curvature is square integrable. (author)
Pseudo-Hermitian quantum dynamics of tachyonic spin-1/2 particles
Jentschura, U D; Wundt, B J
2012-01-01
We investigate the spinor solutions, the spectrum and the symmetry properties of a matrix-valued wave equation whose plane-wave solutions satisfy the superluminal (tachyonic) dispersion relation E 2 = p-vector 2 - m 2 , where E is the energy, p-vector is the spatial momentum and m is the mass of the particle. The equation reads (iγ μ ∂ μ − γ 5 m)ψ = 0, where γ 5 is the fifth current. The tachyonic equation is shown to be CP invariant and T invariant. The tachyonic Hamiltonian breaks parity and is non-Hermitian but fulfils the pseudo-Hermitian property H 5 ( r-vector ) = P H + 5 (- r-vector ) P -1 =P H + 5 ( r-vector ) P -1 , where P is the parity matrix and P is the full parity transformation. The energy eigenvalues and eigenvectors describe a continuous spectrum of plane-wave solutions (which correspond to real eigenvalues for | p-vector |≥m) and evanescent waves, which constitute resonances and anti-resonances with complex-conjugate pairs of resonance eigenvalues (for | p-vector | 5 . This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)
Parity-time symmetry meets photonics: A new twist in non-Hermitian optics
Longhi, Stefano
2017-12-01
In the past decade, the concept of parity-time (PT) symmetry, originally introduced in non-Hermitian extensions of quantum mechanical theories, has come into thinking of photonics, providing a fertile ground for studying, observing, and utilizing some of the peculiar aspects of PT symmetry in optics. Together with related concepts of non-Hermitian physics of open quantum systems, such as non-Hermitian degeneracies (exceptional points) and spectral singularities, PT symmetry represents one among the most fruitful ideas introduced in optics in the past few years. Judicious tailoring of optical gain and loss in integrated photonic structures has emerged as a new paradigm in shaping the flow of light in unprecedented ways, with major applications encompassing laser science and technology, optical sensing, and optical material engineering. In this perspective, I review some of the main achievements and emerging areas of PT -symmetric and non-Hermtian photonics, and provide an outline of challenges and directions for future research in one of the fastest growing research area of photonics.
Yin, Chuanhao; Jiang, Hui; Li, Linhu; Lü, Rong; Chen, Shu
2018-05-01
We unveil the geometrical meaning of winding number and utilize it to characterize the topological phases in one-dimensional chiral non-Hermitian systems. While chiral symmetry ensures the winding number of Hermitian systems are integers, it can take half integers for non-Hermitian systems. We give a geometrical interpretation of the half integers by demonstrating that the winding number ν of a non-Hermitian system is equal to half of the summation of two winding numbers ν1 and ν2 associated with two exceptional points, respectively. The winding numbers ν1 and ν2 represent the times of the real part of the Hamiltonian in momentum space encircling the exceptional points and can only take integers. We further find that the difference of ν1 and ν2 is related to the second winding number or energy vorticity. By applying our scheme to a non-Hermitian Su-Schrieffer-Heeger model and an extended version of it, we show that the topologically different phases can be well characterized by winding numbers. Furthermore, we demonstrate that the existence of left and right zero-mode edge states is closely related to the winding number ν1 and ν2.
Wigner-Smith delay times and the non-Hermitian Hamiltonian for the HOCl molecule
Barr, A.M.; Reichl, L.E.
2013-01-01
We construct the scattering matrix for a two-dimensional model of a Cl atom scattering from an OH dimer. We show that the scattering matrix can be written in terms of a non-Hermitian Hamiltonian whose complex energy eigenvalues can be used to compute Wigner-Smith delay times for the Cl-OH scattering process. We compute the delay times for a range of energies, and show that the scattering states with the longest delay times are strongly influenced by unstable periodic orbits in the classical dynamics. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Positive Eigenvalues of Generalized Words in Two Hermitian Positive Definite Matrices
Hillar, Christopher; Johnson, Charles R.
2005-01-01
We define a word in two positive definite (complex Hermitian) matrices $A$ and $B$ as a finite product of real powers of $A$ and $B$. The question of which words have only positive eigenvalues is addressed. This question was raised some time ago in connection with a long-standing problem in theoretical physics, and it was previously approached by the authors for words in two real positive definite matrices with positive integral exponents. A large class of words that do guarantee positive eig...
Snyder noncommutativity and pseudo-Hermitian Hamiltonians from a Jordanian twist
Castro, P.G.; Kullock, R.; Toppan, F.
2011-01-01
Nonrelativistic quantum mechanics and conformal quantum mechanics are de- formed through a Jordanian twist. The deformed space coordinates satisfy the Snyder noncommutativity. The resulting deformed Hamiltonians are pseudo-Hermitian Hamiltonians of the type discussed by Mostafazadeh. The quantization scheme makes use of the so-called 'unfolded formalism' discussed in previous works. A Hopf algebra structure, compatible with the physical interpretation of the coproduct, is introduced for the Universal Enveloping Algebra of a suitably chosen dynamical Lie algebra (the Hamiltonian is contained among its generators). The multi-particle sector, uniquely determined by the deformed 2-particle Hamiltonian, is composed of bosonic particles. (author)
Multiphoton ionization of H+2 at critical internuclear separations: non-Hermitian Floquet analysis
Likhatov, P V; Telnov, D A
2009-01-01
We present ab initio time-dependent non-Hermitian Floquet calculations of multiphoton ionization (MPI) rates of hydrogen molecular ions subject to an intense linearly polarized monochromatic laser field with a wavelength of 800 nm. The orientation of the molecular axis is parallel to the polarization vector of the laser field. The MPI rates are computed for a wide range of internuclear separations R with high resolution in R and reproduce resonance and near-threshold structures. We show that enhancement of ionization at critical internuclear separations is related to resonance series with higher electronic states. The effect of two-centre interference on the MPI signal is discussed.
Non-Hermitian interaction representation and its use in relativistic quantum mechanics
Znojil, Miloslav
2017-01-01
Roč. 385, č. 10 (2017), s. 162-179 ISSN 0003-4916 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : unitary quantum systems * non-Hermitian version of Dirac's interaction picture * complete set of time-evolution equations * application in relativistic quantum mechanics * Klein-Gordon example with space-time-dependent mass Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics ( physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.465, year: 2016
Snyder noncommutativity and pseudo-Hermitian Hamiltonians from a Jordanian twist
Castro, P.G., E-mail: pgcastro@cbpf.b [Universidade Federal de Juiz de Fora (DM/ICE/UFJF), Juiz de Fora, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Matematica; Kullock, R.; Toppan, F., E-mail: ricardokl@cbpf.b, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica
2011-07-01
Nonrelativistic quantum mechanics and conformal quantum mechanics are de- formed through a Jordanian twist. The deformed space coordinates satisfy the Snyder noncommutativity. The resulting deformed Hamiltonians are pseudo-Hermitian Hamiltonians of the type discussed by Mostafazadeh. The quantization scheme makes use of the so-called 'unfolded formalism' discussed in previous works. A Hopf algebra structure, compatible with the physical interpretation of the coproduct, is introduced for the Universal Enveloping Algebra of a suitably chosen dynamical Lie algebra (the Hamiltonian is contained among its generators). The multi-particle sector, uniquely determined by the deformed 2-particle Hamiltonian, is composed of bosonic particles. (author)
Kamiya, Noriaki; Sato, Matsuo
2014-01-01
We define Hermitian (ϵ,δ)-Freudenthal-Kantor triple systems and prove a structure theorem. We also give some examples of triple systems that are generalizations of the u(N)⊕u(M) and sp(2N)⊕u(1) Hermitian 3-algebras. We apply a *-generalized Jordan triple system to a field theory and obtain a Chern-Simons gauge theory. We find that the novel Higgs mechanism works, where the Chern-Simons gauge theory reduces to a Yang-Mills theory in a certain limit
Akemann, G.; Bender, M.
2010-01-01
We consider a family of chiral non-Hermitian Gaussian random matrices in the unitarily invariant symmetry class. The eigenvalue distribution in this model is expressed in terms of Laguerre polynomials in the complex plane. These are orthogonal with respect to a non-Gaussian weight including a modified Bessel function of the second kind, and we give an elementary proof for this. In the large n limit, the eigenvalue statistics at the spectral edge close to the real axis are described by the same family of kernels interpolating between Airy and Poisson that was recently found by one of the authors for the elliptic Ginibre ensemble. We conclude that this scaling limit is universal, appearing for two different non-Hermitian random matrix ensembles with unitary symmetry. As a second result we give an equivalent form for the interpolating Airy kernel in terms of a single real integral, similar to representations for the asymptotic kernel in the bulk and at the hard edge of the spectrum. This makes its structure as a one-parameter deformation of the Airy kernel more transparent.
Non-hermitian symmetric N = 2 coset models, Poincare polynomials, and string compactification
Fuchs, J.; Schweigert, C.
1994-01-01
The field identification problem, including fixed point resolution, is solved for the non-hermitian symmetric N = 2 superconformal coset theories. Thereby these models are finally identified as well-defined modular invariant conformal field theories. As an application, the theories are used as subtheories in N = 2 tensor products with c = 9, which in turn are taken as the inner sector of heterotic superstring compactifications. All string theories of this type are classified, and the chiral ring as well as the number of massless generations and anti-generations are computed with the help of the extended Poincare polynomial. Several equivalences between a priori different non-hermitian coset theories show up; in particular there is a level-rank duality for an infinite series of coset theories based on C-type Lie algebras. Further, some general results for generic N = 2 coset theories are proven: a simple formula for the number of identification currents is found, and it is shown that the set of Ramond ground states of any N = 2 coset model is invariant under charge conjugation. (orig.)
Bose-Operator Expansions of Tensor Operators in the Theory of Magnetism
Lindgård, Per-Anker; Danielsen, O.
1974-01-01
Using a method of matching corresponding matrix elements, a hermitian Bose-operator expansion of tensor operators of arbitrary rank which transforms all kinematic effects into dynamical interactions between Bose particles is derived. It is shown that the method is a generalization of the Holstein...
Jing, Yan-Fei; Huang, Ting-Zhu; Carpentieri, Bruno; Duan, Yong
An interesting stabilizing variant of the biconjugate A-orthogonal residual (BiCOR) method is investigated for solving dense complex non-Hermitian systems of linear equations arising from the Galerlcin discretization of surface integral equations in electromagnetics. The novel variant is naturally
Diagonalization of Bounded Linear Operators on Separable Quaternionic Hilbert Space
Feng Youling; Cao, Yang; Wang Haijun
2012-01-01
By using the representation of its complex-conjugate pairs, we have investigated the diagonalization of a bounded linear operator on separable infinite-dimensional right quaternionic Hilbert space. The sufficient condition for diagonalizability of quaternionic operators is derived. The result is applied to anti-Hermitian operators, which is essential for solving Schroedinger equation in quaternionic quantum mechanics.
E2-quasi-exact solvability for non-Hermitian models
Fring, Andreas
2015-01-01
We propose the notion of E 2 -quasi-exact solvability and apply this idea to find explicit solutions to the eigenvalue problem for a non-Hermitian Hamiltonian system depending on two parameters. The model considered reduces to the complex Mathieu Hamiltonian in a double scaling limit, which enables us to compute the exceptional points in the energy spectrum of the latter as a limiting process of the zeros for some algebraic equations. The coefficient functions in the quasi-exact eigenfunctions are univariate polynomials in the energy obeying a three-term recurrence relation. The latter property guarantees the existence of a linear functional such that the polynomials become orthogonal. The polynomials are shown to factorize for all levels above the quantization condition leading to vanishing norms rendering them to be weakly orthogonal. In two concrete examples we compute the explicit expressions for the Stieltjes measure. (paper)
E2-quasi-exact solvability for non-Hermitian models
Fring, Andreas
2015-04-01
We propose the notion of E2-quasi-exact solvability and apply this idea to find explicit solutions to the eigenvalue problem for a non-Hermitian Hamiltonian system depending on two parameters. The model considered reduces to the complex Mathieu Hamiltonian in a double scaling limit, which enables us to compute the exceptional points in the energy spectrum of the latter as a limiting process of the zeros for some algebraic equations. The coefficient functions in the quasi-exact eigenfunctions are univariate polynomials in the energy obeying a three-term recurrence relation. The latter property guarantees the existence of a linear functional such that the polynomials become orthogonal. The polynomials are shown to factorize for all levels above the quantization condition leading to vanishing norms rendering them to be weakly orthogonal. In two concrete examples we compute the explicit expressions for the Stieltjes measure.
Sufficient conditions for positivity of non-Markovian master equations with Hermitian generators
Wilkie, Joshua; Wong Yinmei
2009-01-01
We use basic physical motivations to develop sufficient conditions for positive semidefiniteness of the reduced density matrix for generalized non-Markovian integrodifferential Lindblad-Kossakowski master equations with Hermitian generators. We show that it is sufficient for the memory function to be the Fourier transform of a real positive symmetric frequency density function with certain properties. These requirements are physically motivated, and are more general and more easily checked than previously stated sufficient conditions. We also explore the decoherence dynamics numerically for some simple models using the Hadamard representation of the propagator. We show that the sufficient conditions are not necessary conditions. We also show that models exist in which the long time limit is in part determined by non-Markovian effects
On the remarkable spectrum of a non-Hermitian random matrix model
Holz, D E; Orland, H; Zee, A
2003-01-01
A non-Hermitian random matrix model proposed a few years ago has a remarkably intricate spectrum. Various attempts have been made to understand the spectrum, but even its dimension is not known. Using the Dyson-Schmidt equation, we show that the spectrum consists of a non-denumerable set of lines in the complex plane. Each line is the support of the spectrum of a periodic Hamiltonian, obtained by the infinite repetition of any finite sequence of the disorder variables. Our approach is based on the 'theory of words'. We make a complete study of all four-letter words. The spectrum is complicated because our matrix contains everything that will ever be written in the history of the universe, including this particular paper
The area distribution of two-dimensional random walks and non-Hermitian Hofstadter quantum mechanics
Matveenko, Sergey; Ouvry, Stéphane
2014-01-01
When random walks on a square lattice are biased horizontally to move solely to the right, the probability distribution of their algebraic area can be obtained exactly (Mashkevich and Ouvry 2009 J. Stat. Phys. 137 71). We explicitly map this biased classical random system onto a non-Hermitian Hofstadter-like quantum model where a charged particle on a square lattice coupled to a perpendicular magnetic field hops only to the right. For the commensurate case, when the magnetic flux per unit cell is rational, an exact solution of the quantum model is obtained. The periodicity of the lattice allows one to relate traces of the Nth power of the Hamiltonian to probability distribution generating functions of biased walks of length N. (paper)
Wu, Nan; Zhang, Cong; Jin, Xing Ri; Zhang, Ying Qiao; Lee, YoungPak
2018-02-19
Unidirectional reflectionless phenomena are investigated theoretically in a non-Hermitian quantum system composed of several quantum dots and a plasmonic waveguide. By adjusting the phase shifts between quantum dots, single- and dual-band unidirectional reflectionlessnesses are realized at exceptional points based on two and three quantum dots coupled to a plasmonic waveguide, respectively. In addition, single- and dual-band unidirectional perfect absorptions with high quality factors are obtained at the vicinity of exceptional points.
A method to compute the inverse of a complex n-block tridiagonal quasi-hermitian matrix
Godfrin, Elena
1990-01-01
This paper presents a method to compute the inverse of a complex n-block tridiagonal quasi-hermitian matrix using adequate partitions of the complete matrix. This type of matrix is very usual in quantum mechanics and, more specifically, in solid state physics (e.g., interfaces and superlattices), when the tight-binding approximation is used. The efficiency of the method is analyzed comparing the required CPU time and work-area for different usual techniques. (Author)
Adaptive Multigrid Algorithm for the Lattice Wilson-Dirac Operator
Babich, R.; Brower, R. C.; Rebbi, C.; Brannick, J.; Clark, M. A.; Manteuffel, T. A.; McCormick, S. F.; Osborn, J. C.
2010-01-01
We present an adaptive multigrid solver for application to the non-Hermitian Wilson-Dirac system of QCD. The key components leading to the success of our proposed algorithm are the use of an adaptive projection onto coarse grids that preserves the near null space of the system matrix together with a simplified form of the correction based on the so-called γ 5 -Hermitian symmetry of the Dirac operator. We demonstrate that the algorithm nearly eliminates critical slowing down in the chiral limit and that it has weak dependence on the lattice volume.
On the time evolution operator for time-dependent quadratic Hamiltonians
Fernandez, F.M.
1989-01-01
The Schroedinger equation with a time-dependent quadratic Hamiltonian is investigated. The time-evolution operator is written as a product of exponential operators determined by the Heisenberg equations of motion. This product operator is shown to be global in the occupation number representation when the Hamiltonian is Hermitian. The success of some physical applications of the product-form representation is explained
Toppan, Francesco
2004-06-01
Relying upon the division-algebra classification of Clifford algebras and spinors, a classification of generalized supersymmetries (or, with a slight abuse of language, 'generalized super translations') is provided. In each given space-time the maximal, saturated, generalized supersymmetry, compatible with the division-algebra constraint that can be consistently imposed on spinors and on superalgebra generators, is furnished. Constraining the superalgebra generators in both the complex and the quaternionic cases gives rise to the two classes of constrained hermitian and holomorphic generalized supersymmetries. In the complex case these two classes of generalized supersymmetries can be regarded as complementary. The quaternionic holomorphic supersymmetry only exists in certain space-time dimensions and can admit at most a single bosonic scalar central charge. The results here presented pave the way for a better understanding of the various M algebra-type of structures which can be introduced in different space-time signatures and in association with different division algebras, as well as their mutual relations. In a previous work, e.g., the introduction of a complex holomorphic generalized supersymmetry was shown to be necessary in order to perform the analytic continuation of the standard M-theory to the 11-dimensional Euclidean space. As an application of the present results, it is shown that the above algebra also admits a 12-dimensional, Euclidean, F-algebra presentation. (author)
Complexified coherent states and quantum evolution with non-Hermitian Hamiltonians
Graefe, Eva-Maria; Schubert, Roman
2012-01-01
The complex geometry underlying the Schrödinger dynamics of coherent states for non-Hermitian Hamiltonians is investigated. In particular, two seemingly contradictory approaches are compared: (i) a complex WKB formalism, for which the centres of coherent states naturally evolve along complex trajectories, which leads to a class of complexified coherent states; (ii) the investigation of the dynamical equations for the real expectation values of position and momentum, for which an Ehrenfest theorem has been derived in a previous paper, yielding real but non-Hamiltonian classical dynamics on phase space for the real centres of coherent states. Both approaches become exact for quadratic Hamiltonians. The apparent contradiction is resolved building on an observation by Huber, Heller and Littlejohn, that complexified coherent states are equivalent if their centres lie on a specific complex Lagrangian manifold. A rich underlying complex symplectic geometry is unravelled. In particular, a natural complex structure is identified that defines a projection from complex to real phase space, mapping complexified coherent states to their real equivalents. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)
Non-Hermitian multi-particle systems from complex root spaces
Fring, Andreas; Smith, Monique
2012-01-01
We provide a general construction procedure for antilinearly invariant complex root spaces. The proposed method is generic and may be applied to any Weyl group allowing us to take any element of the group as a starting point for the construction. Worked-out examples for several specific Weyl groups are presented, focusing especially on those cases for which no solutions were found previously. When applied to the defining relations of models based on root systems, this usually leads to non-Hermitian models, which are nonetheless physically viable in a self-consistent sense as they are antilinearly invariant by construction. We discuss new types of Calogero models based on these complex roots. In addition, we propose an alternative construction leading to q-deformed roots. We employ the latter type of roots to formulate a new version of affine Toda field theories based on non-simply laced root systems. These models exhibit on the classical level a strong–weak duality in the coupling constant equivalent to a Lie algebraic duality, which is known for the quantum version of the undeformed case. (paper)
Azim, Ali W.; Le Guennec, Yannis; Maury, Ghislaine
2018-05-01
Optical-orthogonal frequency division multiplexing (O-OFDM) is an effective scheme for visible light communications (VLC), offering a candid extension to multiple access (MA) scenarios, i.e., O-OFDMA. However, O-OFDMA exhibits high peak-to-average power ratio (PAPR), which exacerbates the non-linear distortions from the light emitting diode (LED). To overcome high PAPR while sustaining MA, optical-single-carrier frequency-division multiple access (O-SCFDMA) is used. For both O-OFDMA and O-SCFDMA, Hermitian symmetry (HS) constraint is imposed in frequency-domain (FD) to obtain a real-valued time-domain (TD) signal for intensity modulation-direct detection (IM-DD) implementation of VLC. Howbeit, HS results in an increase of PAPR for O-SCFDMA. In this regard, we propose HS free (HSF) O-SCFDMA (HSFO-SCFDMA). We compare HSFO-SCFDMA with several approaches in key parameters, such as, bit error rate (BER), optical power penalty, PAPR, quantization, electrical power efficiency and system complexity. BER performance and optical power penalty is evaluated considering multipath VLC channel and taking into account the bandwidth limitation of LED in combination with its optimized driver. It is illustrated that HSFO-SCFDMA outperforms other alternatives.
Marshman, Emily; Singh, Chandralekha
2018-01-01
In quantum mechanics, for every physical observable, there is a corresponding Hermitian operator. According to the most common interpretation of quantum mechanics, measurement of an observable collapses the quantum state into one of the possible eigenstates of the operator and the corresponding eigenvalue is measured. Since Dirac notation is an elegant notation that is commonly used in upper-level quantum mechanics, it is important that students learn to express quantum operators corresponding to observables in Dirac notation in order to apply the quantum formalism effectively in diverse situations. Here we focus on an investigation that suggests that, even though Dirac notation is used extensively, many advanced undergraduate and PhD students in physics have difficulty expressing the identity operator and other Hermitian operators corresponding to physical observables in Dirac notation. We first describe the difficulties students have with expressing the identity operator and a generic Hermitian operator corresponding to an observable in Dirac notation. We then discuss how the difficulties found via written surveys and individual interviews were used as a guide in the development of a quantum interactive learning tutorial (QuILT) to help students develop a good grasp of these concepts. The QuILT strives to help students become proficient in expressing the identity operator and a generic Hermitian operator corresponding to an observable in Dirac notation. We also discuss the effectiveness of the QuILT based on in-class evaluations.
Fernando, Ranelka G; Balhoff, Mary C; Lopata, Kenneth
2015-02-10
Non-Hermitian real-time time-dependent density functional theory was used to compute the Si L-edge X-ray absorption spectrum of α-quartz using an embedded finite cluster model and atom-centered basis sets. Using tuned range-separated functionals and molecular orbital-based imaginary absorbing potentials, the excited states spanning the pre-edge to ∼20 eV above the ionization edge were obtained in good agreement with experimental data. This approach is generalizable to TDDFT studies of core-level spectroscopy and dynamics in a wide range of materials.
Smith, A.E.; Josefsson, T.W.
1994-01-01
An extension to include general inelastic scattering effects is developed for the case of reflection electron diffraction scattering from surfaces. In this extension of work by Lynch and Moodie, it is shown how the resultant non-Hermitian matrix problem can be recast in a form that is suitable for computation. In particular, a computational method is outlined based on techniques developed by Eberlein for matrix diagonalisation using complex rotations and shears. The resultant methods are applied to the problem of Convergent Beam RHEED. 23 refs., 3 figs
Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields
Puthumpally-Joseph, Raiju; Charron, Eric [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Sukharev, Maxim [Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University, Mesa, Arizona 85212 (United States)
2016-04-21
We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.
Freund, Roland
1988-01-01
Conjugate gradient type methods are considered for the solution of large linear systems Ax = b with complex coefficient matrices of the type A = T + i(sigma)I where T is Hermitian and sigma, a real scalar. Three different conjugate gradient type approaches with iterates defined by a minimal residual property, a Galerkin type condition, and an Euclidian error minimization, respectively, are investigated. In particular, numerically stable implementations based on the ideas behind Paige and Saunder's SYMMLQ and MINRES for real symmetric matrices are proposed. Error bounds for all three methods are derived. It is shown how the special shift structure of A can be preserved by using polynomial preconditioning. Results on the optimal choice of the polynomial preconditioner are given. Also, some numerical experiments for matrices arising from finite difference approximations to the complex Helmholtz equation are reported.
The BL-QMR algorithm for non-Hermitian linear systems with multiple right-hand sides
Freund, R.W. [AT& T Bell Labs., Murray Hill, NJ (United States)
1996-12-31
Many applications require the solution of multiple linear systems that have the same coefficient matrix, but differ in their right-hand sides. Instead of applying an iterative method to each of these systems individually, it is potentially much more efficient to employ a block version of the method that generates iterates for all the systems simultaneously. However, it is quite intricate to develop robust and efficient block iterative methods. In particular, a key issue in the design of block iterative methods is the need for deflation. The iterates for the different systems that are produced by a block method will, in general, converge at different stages of the block iteration. An efficient and robust block method needs to be able to detect and then deflate converged systems. Each such deflation reduces the block size, and thus the block method needs to be able to handle varying block sizes. For block Krylov-subspace methods, deflation is also crucial in order to delete linearly and almost linearly dependent vectors in the underlying block Krylov sequences. An added difficulty arises for Lanczos-type block methods for non-Hermitian systems, since they involve two different block Krylov sequences. In these methods, deflation can now occur independently in both sequences, and consequently, the block sizes in the two sequences may become different in the course of the iteration, even though they were identical at the beginning. We present a block version of Freund and Nachtigal`s quasi-minimal residual method for the solution of non-Hermitian linear systems with single right-hand sides.
Heat transfer operators associated with quantum operations
Aksak, C; Turgut, S
2011-01-01
Any quantum operation applied on a physical system is performed as a unitary transformation on a larger extended system. If the extension used is a heat bath in thermal equilibrium, the concomitant change in the state of the bath necessarily implies a heat exchange with it. The dependence of the average heat transferred to the bath on the initial state of the system can then be found from the expectation value of a Hermitian operator, which is named as the heat transfer operator (HTO). The purpose of this paper is to investigate the relation between the HTOs and the associated quantum operations. Since any given quantum operation on a system can be realized by different baths and unitaries, many different HTOs are possible for each quantum operation. On the other hand, there are also strong restrictions on the HTOs which arise from the unitarity of the transformations. The most important of these is the Landauer erasure principle. This paper is concerned with the question of finding a complete set of restrictions on the HTOs that are associated with a given quantum operation. An answer to this question has been found only for a subset of quantum operations. For erasure operations, these characterizations are equivalent to the generalized Landauer erasure principle. For the case of generic quantum operations, however, it appears that the HTOs obey further restrictions which cannot be obtained from the entropic restrictions of the generalized Landauer erasure principle.
Burda, Zdzislaw, E-mail: zdzislaw.burda@agh.edu.pl [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, PL-30059 Kraków (Poland); Grela, Jacek, E-mail: jacekgrela@gmail.com [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Nowak, Maciej A., E-mail: nowak@th.if.uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Tarnowski, Wojciech, E-mail: wojciech.tarnowski@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Warchoł, Piotr, E-mail: piotr.warchol@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland)
2015-08-15
Following our recent letter, we study in detail an entry-wise diffusion of non-hermitian complex matrices. We obtain an exact partial differential equation (valid for any matrix size N and arbitrary initial conditions) for evolution of the averaged extended characteristic polynomial. The logarithm of this polynomial has an interpretation of a potential which generates a Burgers dynamics in quaternionic space. The dynamics of the ensemble in the large N limit is completely determined by the coevolution of the spectral density and a certain eigenvector correlation function. This coevolution is best visible in an electrostatic potential of a quaternionic argument built of two complex variables, the first of which governs standard spectral properties while the second unravels the hidden dynamics of eigenvector correlation function. We obtain general formulas for the spectral density and the eigenvector correlation function for large N and for any initial conditions. We exemplify our studies by solving three examples, and we verify the analytic form of our solutions with numerical simulations.
Irina Pchelintseva
2008-01-01
Full Text Available We consider self-adjoint unbounded Jacobi matrices with diagonal \\(q_n = b_{n}n\\ and off-diagonal entries \\(\\lambda_n = n\\, where \\(b_{n}\\ is a \\(2\\-periodical sequence of real numbers. The parameter space is decomposed into several separate regions, where the spectrum of the operator is either purely absolutely continuous or discrete. We study the situation where the spectral phase transition occurs, namely the case of \\(b_{1}b_{2} = 4\\. The main motive of the paper is the investigation of asymptotics of generalized eigenvectors of the Jacobi matrix. The pure point part of the spectrum is analyzed in detail.
Nanayakkara, Asiri
2005-01-01
The pseudo Hermiticity with respect to the exchange operators of N-D complex Hamiltonians is investigated. It is shown that if an N-D Hamiltonian is pseudo Hermitian and any eigenfunction of it retains π α T symmetry then the corresponding eigen value is real, where π α is an exchange operator with respect to the permutation α of coordinates and T is the time reversal operator. We construct a special class of N-D pseudo Hermitian Hamiltonians with respect to exchange operators from both N/2-D and N-D general complex Hamiltonians. Examples are presented for Hamiltonians with πT symmetry (π:x↔y, p x ↔p y ) and the reality of these systems are investigated.
Azadi, Mohammad [Sharif University of Technology, Tehran (Iran, Islamic Republic of); Azadi, Mahboobeh [Shiraz University, Shiraz (Iran, Islamic Republic of)
2009-10-15
Nonlinear transient heat transfer and thermoelastic stress analyses of a thick-walled FGM cylinder with temperature dependent materials are performed by using the Hermitian transfinite element method. Temperature-dependency of the material properties has not been taken into account in transient thermoelastic analysis, so far. Due to the mentioned dependency, the resulting governing FEM equations of transient heat transfer are highly nonlinear. Furthermore, in all finite element analysis performed so far in the field, Lagrangian elements have been used. To avoid an artificial local heat source at the mutual boundaries of the elements, Hermitian elements are used instead in the present research. Another novelty of the present paper is simultaneous use of the transfinite element method and updating technique. Time variations of the temperature, displacements, and stresses are obtained through a numerical Laplace inversion. Finally, results obtained considering the temperature-dependency of the material properties are compared with those derived based on temperature independency assumption. Furthermore, the temperature distribution and the radial and circumferential stresses are investigated versus time, geometrical parameters and index of power law. Results reveal that the temperature-dependency effect is significant
On a decomposition theorem for density operators of a pure quantum state
Giannoni, M.J.
1979-03-01
Conditions for the existence of a decomposition of a hermitian projector rho into two hermitian and time reversal invariant operators r/rho 0 and chi under the form rho=esup(i,chi)rho 0 esup(-i,chi) are investigated. Sufficient conditions are given, and an explicit construction of a decomposition is performed when they are fulfilled. A stronger theorem of existence and unicity is studied. All the proofs are valid for any p-body reduced density operator of a pure state of a system of bosons as well as fermions. The decomposition studied in this work has already been used in Nuclear Physics, and may be of interest in other fields of Physics
Spectral correlations of the massive QCD Dirac operator at finite temperature
Seif, Burkhard; Wettig, Tilo; Guhr, Thomas
1999-01-01
We use the graded eigenvalue method, a variant of the supersymmetry technique, to compute the universal spectral correlations of the QCD Dirac operator in the presence of massive dynamical quarks. The calculation is done for the chiral Gaussian unitary ensemble of random matrix theory with an arbitrary Hermitian matrix added to the Dirac matrix. This case is of interest for schematic models of OCD at finite temperature
A comparative study of numerical methods for the overlap Dirac operator--a status report
Eshof, J. van den; Frommer, A.; Lippert, Th.; Schilling, K.; Vorst, H. van der
2002-01-01
Improvements of various methods to compute the sign function of the hermitian Wilson-Dirac matrix within the overlap operator are presented. An optimal partial fraction expansion (PFE) based on a theorem of Zolotarev is given. Benchmarks show that this PFE together with removal of converged systems within a multi-shift CG appears to approximate the sign function times a vector most efficiently. A posteriori error bounds are given
Pawlak, Mariusz; Ben-Asher, Anael; Moiseyev, Nimrod
2018-01-09
We present a simple expression and its derivation for reaction rate coefficients for cold anisotropic collision experiments based on adiabatic variational theory and time-independent non-Hermitian scattering theory. We demonstrate that only the eigenenergies of the resulting one-dimensional Schrödinger equation for different complex adiabats are required. The expression is applied to calculate the Penning ionization rate coefficients of an excited metastable helium atom with molecular hydrogen in an energy range spanning from hundreds of kelvins down to the millikelvin regime. Except for trivial quantities like the masses of the nuclei and the bond length of the diatomic molecule participating in the collision, one needs as input data only the complex potential energy surface (CPES). In calculations, we used recently obtained ab initio CPES by D. Bhattacharya et al. ( J. Chem. Theory Comput. 2017 , 13 , 1682 - 1690 ) without fitting parameters. The results show good accord with current measurements ( Nat. Phys. 2017 , 13 , 35 - 38 ).
Quantum Strategies and Local Operations
Gutoski, Gus
2010-02-01
This thesis is divided into two parts. In Part I we introduce a new formalism for quantum strategies, which specify the actions of one party in any multi-party interaction involving the exchange of multiple quantum messages among the parties. This formalism associates with each strategy a single positive semidefinite operator acting only upon the tensor product of the input and output message spaces for the strategy. We establish three fundamental properties of this new representation for quantum strategies and we list several applications, including a quantum version of von Neumann's celebrated 1928 Min-Max Theorem for zero-sum games and an efficient algorithm for computing the value of such a game. In Part II we establish several properties of a class of quantum operations that can be implemented locally with shared quantum entanglement or classical randomness. In particular, we establish the existence of a ball of local operations with shared randomness lying within the space spanned by the no-signaling operations and centred at the completely noisy channel. The existence of this ball is employed to prove that the weak membership problem for local operations with shared entanglement is strongly NP-hard. We also provide characterizations of local operations in terms of linear functionals that are positive and "completely" positive on a certain cone of Hermitian operators, under a natural notion of complete positivity appropriate to that cone. We end the thesis with a discussion of the properties of no-signaling quantum operations.
BRST operator quantization of generally covariant gauge systems
Ferraro, R.; Sforza, D.M.
1997-01-01
The BRST generator is realized as a Hermitian nilpotent operator for a finite-dimensional gauge system featuring a quadratic super-Hamiltonian and linear supermomentum constraints. As a result, the emerging ordering for the Hamiltonian constraint is not trivial, because the potential must enter the kinetic term in order to obtain a quantization invariant under scaling. Namely, BRST quantization does not lead to the curvature term used in the literature as a means to get that invariance. The inclusion of the potential in the kinetic term, far from being unnatural, is beautifully justified in light of the Jacobi's principle. copyright 1997 The American Physical Society
Hybrid normed ideal perturbations of n-tuples of operators I
Voiculescu, Dan-Virgil
2018-06-01
In hybrid normed ideal perturbations of n-tuples of operators, the normed ideal is allowed to vary with the component operators. We begin extending to this setting the machinery we developed for normed ideal perturbations based on the modulus of quasicentral approximation and an adaptation of our non-commutative generalization of the Weyl-von Neumann theorem. For commuting n-tuples of hermitian operators, the modulus of quasicentral approximation remains essentially the same when Cn- is replaced by a hybrid n-tuple Cp1,…- , … , Cpn- , p1-1 + ⋯ + pn-1 = 1. The proof involves singular integrals of mixed homogeneity.
Spectrum of the Wilson Dirac operator at finite lattice spacings
Akemann, G.; Damgaard, Poul Henrik; Splittorff, Kim
2011-01-01
We consider the effect of discretization errors on the microscopic spectrum of the Wilson Dirac operator using both chiral Perturbation Theory and chiral Random Matrix Theory. A graded chiral Lagrangian is used to evaluate the microscopic spectral density of the Hermitian Wilson Dirac operator...... as well as the distribution of the chirality over the real eigenvalues of the Wilson Dirac operator. It is shown that a chiral Random Matrix Theory for the Wilson Dirac operator reproduces the leading zero-momentum terms of Wilson chiral Perturbation Theory. All results are obtained for fixed index...... of the Wilson Dirac operator. The low-energy constants of Wilson chiral Perturbation theory are shown to be constrained by the Hermiticity properties of the Wilson Dirac operator....
Chen, Yong; Yan, Zhenya
2016-03-22
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields.
Popov, Alexander D.
2010-01-01
We consider the Hermitian Yang-Mills (HYM) equations for gauge potentials on a complex vector bundle E over an almost complex manifold X 6 which is the twistor space of an oriented Riemannian manifold M 4 . Each solution of the HYM equations on such X 6 defines a pseudo-holomorphic structure on the bundle E. It is shown that the pull-back to X 6 of any anti-self-dual gauge field on M 4 is a solution of the HYM equations on X 6 . This correspondence allows us to introduce new twistor actions for bosonic and supersymmetric Yang-Mills theories. As examples of X 6 we consider homogeneous nearly Kaehler and nearly Calabi-Yau manifolds which are twistor spaces of S 4 , CP 2 and B 4 , CB 2 (real 4-ball and complex 2-ball), respectively. Various explicit examples of solutions to the HYM equations on these spaces are provided. Applications in flux compactifications of heterotic strings are briefly discussed.
Calculating the C operator in PT-symmetric quantum mechanics
Bender, C.M.
2004-01-01
It has recently been shown that a non-Hermitian Hamiltonian H possessing an unbroken PT-symmetry (i) has a real spectrum that is bounded below, and (ii) defines a unitary theory of quantum mechanics with positive norm. The proof of unitarity requires a linear operator C, which was originally defined as a sum over the eigenfunctions of H. However, using this definition it is cumbersome to calculate C in quantum mechanics and impossible in quantum field theory. An alternative method is devised here for calculating C directly in terms of the operator dynamical variables of the quantum theory. This new method is general and applies to a variety of quantum mechanical systems having several degrees of freedom. More importantly, this method can be used to calculate the C operator in quantum field theory. The C operator is a new time-independent observable in PT-symmetric quantum field theory. (author)
Rothman, Adam E.; Mazziotti, David A.
2010-03-01
We study molecular conductivity for a one-electron, bath-molecule-bath model Hamiltonian. The primary quantum-mechanical variable is the one-electron reduced density matrix (1-RDM). By identifying similarities between the steady-state Liouville equation and the anti-Hermitian contracted Schrödinger equation (ACSE) [D. A. Mazziotti, Phys. Rev. A 75, 022505 (2007)], we develop a way of enforcing nonequilibrium, steady-state behavior in a time-independent theory. Our results illustrate the relationship between current and voltage in molecular junctions assuming that the total number of electrons under consideration can be fixed across all driving potentials. The impetus for this work is a recent study by Subotnik et al. that also uses the 1-RDM to study molecular conductivity under different assumptions regarding the total number of electrons [J. E. Subotnik et al., J. Chem. Phys. 130, 144105 (2009)]. Unlike calculations in the previous study, our calculations result in 1-RDMs that are fully N-representable. The present work maintains N-representability through a bath-bath mixing that is related to a time-independent relaxation of the baths in the absence of the molecule, as governed by the ACSE. A lack of N-representability can be important since it corresponds to occupying energy states in the molecule or baths with more than one electron or hole (the absence of an electron) in violation of the Pauli principle. For this reason the present work may serve as an important, albeit preliminary, step in designing a 2-RDM/ACSE method for studying steady-state molecular conductivity with an explicit treatment of electron correlation.
Nachtigal, Noel M.
1991-01-01
The Lanczos algorithm can be used both for eigenvalue problems and to solve linear systems. However, when applied to non-Hermitian matrices, the classical Lanczos algorithm is susceptible to breakdowns and potential instabilities. In addition, the biconjugate gradient (BCG) algorithm, which is the natural generalization of the conjugate gradient algorithm to non-Hermitian linear systems, has a second source of breakdowns, independent of the Lanczos breakdowns. Here, we present two new results. We propose an implementation of a look-ahead variant of the Lanczos algorithm which overcomes the breakdowns by skipping over those steps where a breakdown or a near-breakdown would occur. The new algorithm can handle look-ahead steps of any length and requires the same number of matrix-vector products and inner products per step as the classical Lanczos algorithm without look-ahead. Based on the proposed look-ahead Lanczos algorithm, we then present a novel BCG-like approach, the quasi-minimal residual (QMR) method, which avoids the second source of breakdowns in the BCG algorithm. We present details of the new method and discuss some of its properties. In particular, we discuss the relationship between QMR and BCG, showing how one can recover the BCG iterates, when they exist, from the QMR iterates. We also present convergence results for QMR, showing the connection between QMR and the generalized minimal residual (GMRES) algorithm, the optimal method in this class of methods. Finally, we give some numerical examples, both for eigenvalue computations and for non-Hermitian linear systems.
Euler polynomials and identities for non-commutative operators
De Angelis, Valerio; Vignat, Christophe
2015-12-01
Three kinds of identities involving non-commutating operators and Euler and Bernoulli polynomials are studied. The first identity, as given by Bender and Bettencourt [Phys. Rev. D 54(12), 7710-7723 (1996)], expresses the nested commutator of the Hamiltonian and momentum operators as the commutator of the momentum and the shifted Euler polynomial of the Hamiltonian. The second one, by Pain [J. Phys. A: Math. Theor. 46, 035304 (2013)], links the commutators and anti-commutators of the monomials of the position and momentum operators. The third appears in a work by Figuieira de Morisson and Fring [J. Phys. A: Math. Gen. 39, 9269 (2006)] in the context of non-Hermitian Hamiltonian systems. In each case, we provide several proofs and extensions of these identities that highlight the role of Euler and Bernoulli polynomials.
Generalized space and linear momentum operators in quantum mechanics
Costa, Bruno G. da; Borges, Ernesto P.
2014-01-01
We propose a modification of a recently introduced generalized translation operator, by including a q-exponential factor, which implies in the definition of a Hermitian deformed linear momentum operator p ^ q , and its canonically conjugate deformed position operator x ^ q . A canonical transformation leads the Hamiltonian of a position-dependent mass particle to another Hamiltonian of a particle with constant mass in a conservative force field of a deformed phase space. The equation of motion for the classical phase space may be expressed in terms of the generalized dual q-derivative. A position-dependent mass confined in an infinite square potential well is shown as an instance. Uncertainty and correspondence principles are analyzed
Low-lying eigenmodes of the Wilson-Dirac operator and correlations with topological objects
Kusterer, Daniel-Jens; Hedditch, John; Kamleh, Waseem; Leinweber, D.B.; Williams, Anthony G.
2002-01-01
The probability density of low-lying eigenvectors of the hermitian Wilson-Dirac operator H(κ)=γ 5 D W (κ) is examined. Comparisons in position and size between eigenvectors, topological charge and action density are made. We do this for standard Monte-Carlo generated SU(3) background fields and for single instanton background fields. Both hot and cooled SU(3) background fields are considered. An instanton model is fitted to eigenmodes and topological charge density and the sizes and positions of these are compared
Malik, R. P.; Srinivas, N.; Bhanja, T.
2016-01-01
We exploit the key concepts of the augmented version of superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism to derive the superspace (SUSP) dual unitary operator and its Hermitian conjugate and demonstrate their utility in the derivation of the nilpotent and absolutely anticommuting (anti-)dual-BRST symmetry transformations for a set of interesting models of the Abelian 1-form gauge theories. These models are the one (0+1)-dimensional (1D) rigid rotor and modified versions of the two (1+1)-dimensional (2D) Proca as well as anomalous gauge theories and 2D model of a self-dual bosonic field theory. We show the universality of the SUSP dual unitary operator and its Hermitian conjugate in the cases of all the Abelian models under consideration. These SUSP dual unitary operators, besides maintaining the explicit group structure, provide the alternatives to the dual horizontality condition (DHC) and dual gauge invariant restrictions (DGIRs) of the superfield formalism. The derivations of the dual unitary operators and corresponding (anti-)dual-BRST symmetries are completely novel results in our present investigation.
Singular Spectrum Near a Singular Point of Friedrichs Model Operators of Absolute Type
Iakovlev, Serguei I.
2006-01-01
In L 2 (R) we consider a family of self adjoint operators of the Friedrichs model: A m =|t| m +V. Here |t| m is the operator of multiplication by the corresponding function of the independent variable t element of R, and (perturbation) is a trace-class integral operator with a continuous Hermitian kernel ν(t,x) satisfying some smoothness condition. These absolute type operators have one singular point of order m>0. Conditions on the kernel ν(t,x) are found guaranteeing the absence of the point spectrum and the singular continuous one of such operators near the origin. These conditions are actually necessary and sufficient. They depend on the finiteness of the rank of a perturbation operator and on the order of singularity. The sharpness of these conditions is confirmed by counterexamples
Hermitian-to-quasi-Hermitian quantum phase transitions
Znojil, Miloslav
Roč. 97, č. 4 ( 2018 ), č. článku 042117. ISSN 2469-9926 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : quantum phase transition * PT-symmetric * Herimiticity Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.925, year: 2016
Thomson, C. J.
2015-08-01
The properties of the overburden transmission response are of particular interest for the analysis of reflectivity illumination or blurring in seismic depth imaging. The first step to showing a transmission-operator reciprocity property is to identify the symmetry of the so-called displacement-to-traction operators. The latter are analogous to Dirichlet-to-Neumann operators and they may also be called impedance operators. Their symmetry is deduced here after development of a formal spectral or modal theory of lateral wavefunctions in a laterally heterogeneous generally anisotropic elastic medium. The elastic lateral modes are displacement-traction 6-vectors and they are built from two auxiliary 3-vector lateral-mode bases. These auxiliary modes arise from Hermitian and anti-Hermitian operators, so they have familiar properties such as orthogonality. There is no assumption of down/up symmetry of the elasticity tensor, but basic assumptions are made about the existence and completeness of the elastic modes. A point-symmetry property appears and plays a central role. The 6-vector elastic modes have a symplectic orthogonality property, which facilitates the development of modal expansions for 6-vector functions of the lateral coordinates when completeness is assumed. While the elastic modal theory is consistent with the laterally homogeneous case, numerical work would provide confidence that it is correct in general. An appendix contains an introductory overview of acoustic lateral modes that were studied by other authors, given from the perspective of this new work. A distinction is drawn between unit normalization of scalar auxiliary modes and a separate energy-flux normalization of 2-vector acoustic modes. Neither is crucial to the form of acoustic pressure-to-velocity or impedance operators. This statement carries over to the elastic case for the 3-vector auxiliary- and 6-vector elastic-mode normalizations. The modal theory is used to construct the kernel of the
Analysis of unbounded operators and random motion
Jorgensen, Palle E. T.
2009-01-01
We study infinite weighted graphs with view to 'limits at infinity' or boundaries at infinity. Examples of such weighted graphs arise in infinite (in practice, that means 'very' large) networks of resistors or in statistical mechanics models for classical or quantum systems. However, more generally, our analysis includes reproducing kernel Hilbert spaces and associated operators on them. If X is some infinite set of vertices or nodes, in applications the essential ingredient going into the definition is a reproducing kernel Hilbert space; it measures the differences of functions on X evaluated on pairs of points in X. Moreover, the Hilbert norm-squared in H(X) will represent a suitable measure of energy. Associated unbounded operators will define a notion or dissipation, it can be a graph Laplacian or a more abstract unbounded Hermitian operator defined from the reproducing kernel Hilbert space under study. We prove that there are two closed subspaces in reproducing kernel Hilbert space H(X) that measure quantitative notions of limits at infinity in X: one generalizes finite-energy harmonic functions in H(X) and the other a deficiency index of a natural operator in H(X) associated directly with the diffusion. We establish these results in the abstract, and we offer examples and applications. Our results are related to, but different from, potential theoretic notions of 'boundaries' in more standard random walk models. Comparisons are made.
General operator form of the non-local three-nucleon force
Topolnicki, K. [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland)
2017-09-15
This paper describes a procedure to obtain the general form of the three-nucleon force. The result is an operator form where the momentum space matrix element of the three-nucleon potential is written as a linear combination of 320 isospin-spin-momentum operators and scalar functions of momenta. Any spatial and isospin rotation invariant three-nucleon force can be written in this way and in order for the potential to be Hermitian, symmetric under parity inversion, time reversal and particle exchange, the scalar functions must have definite transformation properties under these discrete operations. A complete list of the isospin-spin-momentum operators and scalar function transformation properties is given. (orig.)
Kalkreuter, T.; Simma, H.
1995-07-01
The low-lying eigenvalues of a (sparse) hermitian matrix can be computed with controlled numerical errors by a conjugate gradient (CG) method. This CG algorithm is accelerated by alternating it with exact diagonalizations in the subspace spanned by the numerically computed eigenvectors. We study this combined algorithm in case of the Dirac operator with (dynamical) Wilson fermions in four-dimensional SU(2) gauge fields. The algorithm is numerically very stable and can be parallelized in an efficient way. On lattices of sizes 4 4 - 16 4 an acceleration of the pure CG method by a factor of 4 - 8 is found. (orig.)
A note on the correspondence between qubit quantum operations and special relativity
Arrighi, Pablo [Computer Laboratory, University of Cambridge, 15 JJ Thomson Avenue, Cambridge CB3 0FD (United Kingdom); Patricot, Christophe [DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2003-05-23
We exploit a well-known isomorphism between complex Hermitian 2 x 2 matrices and R{sup 4}, which yields a convenient real vector representation of qubit states. Because these do not need to be normalized we find that they map onto a Minkowskian future cone in E{sup 1,3}, whose vertical cross-sections are nothing but Bloch spheres. Pure states are represented by light-like vectors, unitary operations correspond to special orthogonal transforms about the axis of the cone, positive operations correspond to pure Lorentz boosts. We formalize the equivalence between the generalized measurement formalism on qubit states and the Lorentz transformations of special relativity, or more precisely elements of the restricted Lorentz group together with future-directed null boosts. The note ends with a discussion of the equivalence and some of its possible consequences. (letter to the editor)
A note on the correspondence between qubit quantum operations and special relativity
Arrighi, Pablo; Patricot, Christophe
2003-01-01
We exploit a well-known isomorphism between complex Hermitian 2 x 2 matrices and R 4 , which yields a convenient real vector representation of qubit states. Because these do not need to be normalized we find that they map onto a Minkowskian future cone in E 1,3 , whose vertical cross-sections are nothing but Bloch spheres. Pure states are represented by light-like vectors, unitary operations correspond to special orthogonal transforms about the axis of the cone, positive operations correspond to pure Lorentz boosts. We formalize the equivalence between the generalized measurement formalism on qubit states and the Lorentz transformations of special relativity, or more precisely elements of the restricted Lorentz group together with future-directed null boosts. The note ends with a discussion of the equivalence and some of its possible consequences. (letter to the editor)
Emitter and absorber assembly for multiple self-dual operation and directional transparency
Kalozoumis, P. A.; Morfonios, C. V.; Kodaxis, G.; Diakonos, F. K.; Schmelcher, P.
2017-03-01
We demonstrate how to systematically design wave scattering systems with simultaneous coherent perfect absorbing and lasing operation at multiple and prescribed frequencies. The approach is based on the recursive assembly of non-Hermitian emitter and absorber units into self-dual emitter-absorber trimers at different composition levels, exploiting the simple structure of the corresponding transfer matrices. In particular, lifting the restriction to parity-time-symmetric setups enables the realization of emitter and absorber action at distinct frequencies and provides flexibility with respect to the choice of realistic parameters. We further show how the same assembled scatterers can be rearranged to produce unidirectional and bidirectional transparency at the selected frequencies. With the design procedure being generically applicable to wave scattering in single-channel settings, we demonstrate it with concrete examples of photonic multilayer setups.
EISPACK, Subroutines for Eigenvalues, Eigenvectors, Matrix Operations
Garbow, Burton S.; Cline, A.K.; Meyering, J.
1993-01-01
1 - Description of problem or function: EISPACK3 is a collection of 75 FORTRAN subroutines, both single- and double-precision, that compute the eigenvalues and eigenvectors of nine classes of matrices. The package can determine the Eigen-system of complex general, complex Hermitian, real general, real symmetric, real symmetric band, real symmetric tridiagonal, special real tridiagonal, generalized real, and generalized real symmetric matrices. In addition, there are two routines which use the singular value decomposition to solve certain least squares problem. The individual subroutines are - Identification/Description: BAKVEC: Back transform vectors of matrix formed by FIGI; BALANC: Balance a real general matrix; BALBAK: Back transform vectors of matrix formed by BALANC; BANDR: Reduce sym. band matrix to sym. tridiag. matrix; BANDV: Find some vectors of sym. band matrix; BISECT: Find some values of sym. tridiag. matrix; BQR: Find some values of sym. band matrix; CBABK2: Back transform vectors of matrix formed by CBAL; CBAL: Balance a complex general matrix; CDIV: Perform division of two complex quantities; CG: Driver subroutine for a complex general matrix; CH: Driver subroutine for a complex Hermitian matrix; CINVIT: Find some vectors of complex Hess. matrix; COMBAK: Back transform vectors of matrix formed by COMHES; COMHES: Reduce complex matrix to complex Hess. (elementary); COMLR: Find all values of complex Hess. matrix (LR); COMLR2: Find all values/vectors of cmplx Hess. matrix (LR); CCMQR: Find all values of complex Hessenberg matrix (QR); COMQR2: Find all values/vectors of cmplx Hess. matrix (QR); CORTB: Back transform vectors of matrix formed by CORTH; CORTH: Reduce complex matrix to complex Hess. (unitary); CSROOT: Find square root of complex quantity; ELMBAK: Back transform vectors of matrix formed by ELMHES; ELMHES: Reduce real matrix to real Hess. (elementary); ELTRAN: Accumulate transformations from ELMHES (for HQR2); EPSLON: Estimate unit roundoff
Quantum measurement with a positive operator-valued measure
Brandt, Howard E
2003-01-01
In the quantum theory of measurement, the positive operator-valued measure (POVM) is an important concept, and its implementation can be useful. A POVM consists of a set of non-negative quantum-mechanical Hermitian operators that add up to the identity. The probability that a quantum system is in a particular state is given by the expectation value of the POVM operator corresponding to that state. Following a brief review of the mathematics and mention of the history of POVMs in quantum theory, a particular implementation of a POVM for use in the measurement of nonorthogonal photon polarization states is reviewed. The implementation consists simply of a Wollaston prism, a mirror, two beam splitters, a polarization rotator and three phototubes arranged in an interferometric configuration, and it is shown analytically that the device faithfully represents the POVM. Based on Neumark's extension theorem, the two-dimensional Hilbert space of the POVM implementation can be embedded in the three-dimensional Hilbert space of an ordinary projective-valued measure. Also, analytical expressions are given for the maximum Renyi information loss from the device to a disturbing probe, and for the error and inconclusive rates induced by the probe. Various aspects of the problem of probe optimization are elaborated
Carlos A Bustamante Chaverra
2013-03-01
Full Text Available Un método sin malla es desarrollado para solucionar una versión genérica de la ecuación no lineal de convección-difusión-reacción en dominios bidimensionales. El método de Interpolación Local Hermítica (LHI es empleado para la discretización espacial, y diferentes estrategias son implementadas para solucionar el sistema de ecuaciones no lineales resultante, entre estas iteración de Picard, método de Newton-Raphson y el Método de Homotopía truncado (HAM. En el método LHI las Funciones de Base Radial (RBFs son empleadas para construir una función de interpolación. A diferencia del Método de Kansa, el LHI es aplicado localmente y los operadores diferenciales de las condiciones de frontera y la ecuación gobernante son utilizados para construir la función de interpolación, obteniéndose una matriz de colocación simétrica. El método de Newton-Rapshon se implementa con matriz Jacobiana analítica y numérica, y las derivadas de la ecuación gobernante con respecto al paramétro de homotopía son obtenidas analíticamente. El esquema numérico es veriﬁcado mediante la comparación de resultados con las soluciones analíticas de las ecuaciones de Burgers en una dimensión y Richards en dos dimensiones. Similares resultados son obtenidos para todos los solucionadores que se probaron, pero mejores ratas de convergencia son logradas con el método de Newton-Raphson en doble iteración.A meshless numerical scheme is developed for solving a generic version of the non-linear convection-diﬀusion-reaction equation in two-dim-ensional domains. The Local Hermitian Interpolation (LHI method is employed for the spatial discretization and several strategies are implemented for the solution of the resulting non-linear equation system, among them the Picard iteration, the Newton Raphson method and a truncated version of the Homotopy Analysis Method (HAM. The LHI method is a local collocation strategy in which Radial Basis Functions (RBFs
Pseudo-Hermitian Representation of Quantum Mechanics
Mustafazade, A.
2008-01-01
I will outline a formulation of quantum mechanics in which the inner product on the Hilbert space of a quantum system is treated as a degree of freedom. I will outline some of the basic mathematical and conceptual features of the resulting theory and discuss some of its applications. In particular, I will present a quantum mechanical analogue of Einstein's field equations that links the inner product of the Hilbert space and the Hamiltonian of the system and discuss how the resulting theory can be used to address a variety of problems in classical electrodynamics, relativistic quantum mechanics, and quantum computation
Pseudo-Hermitian random matrix theory
Srivastava, S.C.L.; Jain, S.R.
2013-01-01
Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Entanglement in non-Hermitian quantum theory
hope that the entanglement in PT -symmetric quantum theory may provide new ways of processing information in the quantum world. We conclude our .... Similarly, if we have a two-level atom, then an arbitrary superposition of the ground state ...
Anda VELICANU
2010-09-01
Full Text Available This paper contains a brief description of the most important operations that can be performed on spatial data such as spatial queries, create, update, insert, delete operations, conversions, operations on the map or analysis on grid cells. Each operation has a graphical example and some of them have code examples in Oracle and PostgreSQL.
Dostal, Jiri
1993-01-01
This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits
November, L.J.
1993-01-01
Formulas are presented for the recovery of the matrix operators in arbitrary-order similarity and congruency transformations. Two independent input and output matrix pairs exactly determine the similarity-transformation matrix operator, while three independent Hermitian-matrix pairs are required for the congruency-transformation operator. The congruency transformation is the natural form for the quantum observables of a multiple-element wave function, e.g., for polarized-light transfer: the recovery of the Jones matrix for a nondepolarizing device is demonstrated, given any three linearly independent partially polarized input Stokes states. The recovery formula gives a good solution even with large added noise in the test matrices. Combined with numerical least-squares methods, the formula can give an optimized solution for measures of observation error. A more general operator, which includes the effect of isotropic depolarization, is defined, and its recovery is demonstrated also. The recovery formulas have a three-dimensional geometric interpretation in the second-order case, e.g., in the Poincare sphere. It is pointed out that the geometric property is a purely mathematical property of quantum observables that arises without referring to spatial characteristics for the underlying wave function. 36 refs., 9 figs
Tsichritzis, Dionysios C; Rheinboldt, Werner
1974-01-01
Operating Systems deals with the fundamental concepts and principles that govern the behavior of operating systems. Many issues regarding the structure of operating systems, including the problems of managing processes, processors, and memory, are examined. Various aspects of operating systems are also discussed, from input-output and files to security, protection, reliability, design methods, performance evaluation, and implementation methods.Comprised of 10 chapters, this volume begins with an overview of what constitutes an operating system, followed by a discussion on the definition and pr
Boehme, Thomas K
1987-01-01
Operational Calculus, Volume II is a methodical presentation of operational calculus. An outline of the general theory of linear differential equations with constant coefficients is presented. Integral operational calculus and advanced topics in operational calculus, including locally integrable functions and convergence in the space of operators, are also discussed. Formulas and tables are included.Comprised of four sections, this volume begins with a discussion on the general theory of linear differential equations with constant coefficients, focusing on such topics as homogeneous and non-ho
Crypto-Unitary Forms of Quantum Evolution Operators
Znojil, Miloslav
2013-01-01
Roč. 52, č. 6 (2013), s. 2038-2045 ISSN 0020-7748 R&D Projects: GA ČR GAP203/11/1433 Institutional support: RVO:61389005 Keywords : PT-symmetric quantum mechanics * time-dependent Schrödinger equation * manifestly time-dependent Hermitian Hamiltonians * Manifestly time-dependent Dyson maps * equivalent time-independent non-Hermitian Hamiltonians Subject RIV: BE - Theoretical Physics Impact factor: 1.188, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs10773-012-1451-9.pdf
Sellmaier, Florian; Schmidhuber, Michael
2015-01-01
The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).
Hautus, M.L.J.
1994-01-01
Substitution of an operator into an operator-valued map is defined and studied. A Bezout-type remainder theorem is used to derive a number of results. The tensor map is used to formulate solvability conditions for linear matrix equations. Some applications to system theory are given, in particular
Tetsuya, Saito; Nauta, Bram
2008-01-01
To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a differential amplifier circuit 1;
Tetsuya, Saito; Nauta, Bram
2011-01-01
PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a
Tetsuya, S.; Nauta, Bram
2007-01-01
PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. ; SOLUTION: The operation amplifier comprises: a
Anon.
1979-01-01
Operations of the SuperHILAC, the Bevatron/Bevalac, and the 184-inch Synchrocyclotron during the period from October 1977 to September 1978 are discussed. These include ion source development, accelerator facilities, the Heavy Ion Spectrometer System, and Bevelac biomedical operations
Lee, Ji Bok; Jeon, Byung Jin; Kwack, Byung Ho
1997-01-01
HANARO was configurated its first operating core in 1995. Long term operation test was conducted up to 3-1 cycle during 1996, in order to investigate the reactor characteristics due to fuel depletion and additional fuel loading. Now HANARO has accumulated 168.4 days of total operation time and 2,687.5 MWD of total thermal output. Reactor analysis, producing operation datum and its validation with test, periodic inspection and maintenance of the facility are continuously conducted for safe operation of the HANARO. Conducted the verification tests for installed utilization facilities, and successfully performed the radiation emergency drill. The shutdown report of TRIGA Mark II and III was submitted to MOST, and decommissioning will be started from 1997. (author). 70 tabs., 50 figs., 27 refs
Shaw, J
2013-01-01
Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp
Operator programs and operator processes
Bergstra, J.A.; Walters, P.
2003-01-01
We define a notion of program which is not a computer program but an operator program: a detailed description of actions performed and decisions taken by a human operator (computer user) performing a task to achieve a goal in a simple setting consisting of that user, one or more computers and a
2015-01-01
A one-sentence definition of operator theory could be: The study of (linear) continuous operations between topological vector spaces, these being in general (but not exclusively) Fréchet, Banach, or Hilbert spaces (or their duals). Operator theory is thus a very wide field, with numerous facets, both applied and theoretical. There are deep connections with complex analysis, functional analysis, mathematical physics, and electrical engineering, to name a few. Fascinating new applications and directions regularly appear, such as operator spaces, free probability, and applications to Clifford analysis. In our choice of the sections, we tried to reflect this diversity. This is a dynamic ongoing project, and more sections are planned, to complete the picture. We hope you enjoy the reading, and profit from this endeavor.
Mason, Gerald
2002-01-01
More than 1,250,000 tons of shipping was sunk or damaged in the last five months of World War II when Twenty-first Bomber Command executed an aerial mining campaign against Japan known as Operation STARVATION...
Proks, Josef
2000-01-01
Peace operations are more and more important in the contemporary world. The end of the Cold War increased not only possibilities of solving disputes by the international community but also by the number and diversity of threats and issues...
Wirstad, J.
1983-12-01
The traditional operator job is changing, which among other things has generated a need for better job training. Surprisingly increased process automation has lead to increased operator qualifications, i.e. basic job training but also up-date and rehearsal training within certain fixed intervals. There are several, similar models for instructional system development available in the literature. One model which is of special interest integrates Operator Training development and Man-Machine Interfaces development. The extent to which Systematic Operator Training has been implemented varies with branches and companies. The nuclear power branch is given as an example in the report. This branch probably represents something better than the average among the process industries.(author)
Wistoft, Karen; Højlund, Holger
2012-01-01
educational goals, learning content, or value clarification. Health pedagogy is often a matter of retrospective rationalization rather than the starting point of planning. Health and risk behaviour approaches override health educational approaches. Conclusions: Operational links between health education......, health professionalism, and management strategies pose the foremost challenge. Operational links indicates cooperative levels that facilitate a creative and innovative effort across traditional professional boundaries. It is proposed that such links are supported by network structures, shared semantics...
Applied Operations Research: Operator's Assistant
Cole, Stuart K.
2015-01-01
NASA operates high value critical equipment (HVCE) that requires trouble shooting, periodic maintenance and continued monitoring by Operations staff. The complexity HVCE and information required to maintain and trouble shoot HVCE to assure continued mission success as paper is voluminous. Training on new HVCE is commensurate with the need for equipment maintenance. LaRC Research Directorate has undertaken a proactive research to support Operations staff by initiation of the development and prototyping an electronic computer based portable maintenance aid (Operator's Assistant). This research established a goal with multiple objectives and a working prototype was developed. The research identified affordable solutions; constraints; demonstrated use of commercial off the shelf software; use of the US Coast Guard maintenance solution; NASA Procedure Representation Language; and the identification of computer system strategies; where these demonstrations and capabilities support the Operator, and maintenance. The results revealed validation against measures of effectiveness and overall proved a substantial training and capability sustainment tool. The research indicated that the OA could be deployed operationally at the LaRC Compressor Station with an expectation of satisfactorily results and to obtain additional lessons learned prior to deployment at other LaRC Research Directorate Facilities. The research revealed projected cost and time savings.
McRae, L.P.; Six, D.E.
1991-01-01
In 1987, Westinghouse Hanford Company began operating a first-generation integrated safeguards system in the Plutonium Finishing Plant storage vaults. This Vault Safety and Inventory System is designed to integrate data into a computer-based nuclear material inventory monitoring system. The system gathers, in real time, measured physical parameters that generate nuclear material inventory status data for thousands of stored items and sends tailored report to the appropriate users. These data include canister temperature an bulge data reported to Plant Operations and Material Control and Accountability personnel, item presence and identification data reported to Material Control and Accountability personnel, and unauthorized item movement data reported to Security response forces and Material Control and Accountability personnel. The Westinghouse Hanford Company's experience and operational benefits in using this system for reduce radiation exposure, increase protection against insider threat, and real-time inventory control are discussed in this paper
Natalizio, A.; Anderson, J.W.D.; Sills, H.E.
1988-01-01
Abundant, cheap computing power has provided industry with a far greater opportunity than was available one or two decades ago to automate industrial processes and to improve the man-machine interface. Exciting innovations in knowledge representation methods arising from artificial intelligence research pave the way for advanced support systems for assisting plant operators. AECL has recognized the importance of knowledge based system technology, particularly expert systems, in the achievement of this objective and also, as a strategic technology to be fully exploited in the next generation of CANDU reactors. Operator Companion, an expert system intended to diagnose plant faults and advise the operator on appropriate restoring or corrective actions, is a major undertaking which is receiving support within the research and engineering groups of AECL
Guhl, J F
1979-01-01
In a period of 20 months, over 200 patients (age ranged from high school students to middle-aged persons) with knee injuries were treated by operative arthroscopy. The majority of the injuries were incurred while the patients had been participating in athletic events, either competitive or recreational. Operative arthroscopy offers the advantage of shortened hospital stay, rapid rehabilitation, lack of disfiguring scar, and reduced costs. Patients are followed yearly after the first postoperative year. Improved long-term results from diagnostic and operative arthroscopy, as compared to conventional surgical procedures, are expected. The proof of those expectations will be determined in the next several years as this group of patients requiring partial meniscectomies or procedures for pathologic and degenerative conditions is reevaluated.
Anon.
1980-01-01
This section is concerned with the operation of both the tandem-linac system and the Dynamitron, two accelerators that are used for entirely different research. Developmental activities associated with the tandem and the Dynamitron are also treated here, but developmental activities associated with the superconducting linac are covered separately because this work is a program of technology development in its own right
areas in which this type is useful are multimedia, virtual reality, and advanced scientific projects such as undersea exploration and planetary rovers. Because of the expanded uses for soft real-time functionality, it is finding its way into most current operating systems, including major versions of Unix and Windows NT OS.
Lewis, William
1995-01-01
.... Indeed, despite the energetic leadership of Under Secretary-General Kofi R. Annan who directs the Department of Peacekeeping Operations, the organization has increasing difficulty in acquiring properly trained and equipped forces in time to intervene in conflict situations and humanitarian crises.
2003-01-01
Operational Circular N° 4 - April 2003 Conditions for use by members of the CERN personnel of vehicles belonging to or rented by CERN - This circular has been drawn up. Operational Circular N° 5 - October 2000 Use of CERN computing facilities - Further details on the personal use of CERN computing facilities Operational Circular N° 5 and its Subsidiary Rules http://cern.ch/ComputingRules defines the rules for the use of CERN computing facilities. One of the basic principles governing such use is that it must come within the professional duties of the user concerned, as defined by the user's divisional hierarchy. However, personal use of the computing facilities is tolerated or allowed provided : a) It is in compliance with Operational Circular N° 5 and not detrimental to official duties, including those of other users; b) the frequency and duration is limited and there is a negligible use of CERN resources; c) it does not constitute a political, commercial and/or profit-making activity; d) it is not...
Stüben, Henning; Tietjen, Anne
2006-01-01
Abstract: This paper seeks to challenge the notion of context from an operational perspective. Can we grasp the forces that shape the complex conditions for an architectural or urban design within the notion of context? By shifting the gaze towards the agency of architecture, contextual analysis...
2010-01-01
The chapter presents the operational indicators related to budget, travel costs and tickets, the evolution of the annual program for regulatory inspection, the scientific production, requested patents and the numbers related to the production of the services offered by the Institution
House, W.B.; Ebenhack, D.G.
1989-01-01
This chapter is a discussion of the management and operations practices used at the Barnwell Waste Management Facility in Barnwell, SC. The following topics are discussed: (1) Waste receiving and inspection, including manifest and certificates of compliance, radiological surveys, disposition of nonconforming items, and decontamination and disposition of secondary waste streams; (2) Waste disposal, including Title 10 CFR 61 requirements, disposal area evaluations, shipment offloading, container emplacement, and radiation protection; (3) Trench closure, including trench backfilling, trench capping, and permanent markers; (4) Site maintenance and stabilization, including trench maintenance, surface water management, and site closure activities; (5) Site monitoring programs, including operational monitoring, and environmental monitoring program; (6) Personnel training and qualifications, including basic training program, safety training program, special skills training, and physical qualifications; (7) Records management, including waste records, personnel training records, personnel dosimetry records, site monitoring records, trench qualification and construction records, and site drawings and stabilization records; (8) Site security; (9) Emergency response plans; and (10) Quality assurance
Scragg, D.M.
1991-01-01
There are very few Energy from Municipal Waste processing plants in the U.K. Those which were built have usually been financed and operated by Local Authorities and are now in excess of 17 years old. The Environmental Protection Act and constraints on Public Sector spending have brought about fundamental changes in the approach taken to developing new schemes of this kind. The Public Sector and the Private Sector must work together. The investment in Mass Burning Incineration Schemes generating energy is high and the pressures to keep the waste disposal costs as low as possible mean that recovery of the investment needs to be spread over many years. For any Scheme to be successful and financially viable requires a long term commitment on the part of those involved. This paper sets out the key role which the Operating Contractor can play in this situation. (author)
Launeau, F.
2016-01-01
The CIGEO facility dedicated to the geological disposal of high- and intermediate-level radioactive wastes will be composed of 2 parts: an underground facility at a depth of 500 m to dispose the waste packages in tunnels and a surface facility to take delivery of the wastes and prepare the packages. The underground facility will be built progressively and will cover a surface of 15 km 2 at the end of Cigeo operating-life. A large part of the surface facility (located a few km away from the waste reception place) will be dedicated to the works led deep underground to build the tunnels and will receive drilling cuttings. The article describes also the ramp and carts to lead waste packages underground. Most of the operations will be automated. The definitive closure of the tunnels will be made with swelling clay and concrete plugs. (A.C.)
Pruvost, N.; Tsitouras, J.
1981-01-01
The objectives of Operation Poorman were to design and build a portable seismic system and to set up and use this system in a cold-weather environment. The equipment design uses current technology to achieve a low-power, lightweight system that is configured into three modules. The system was deployed in Alaska during wintertime, and the results provide a basis for specifying a mission-ready seismic verification system
Knuefer; Lindauer
1980-01-01
Besides that at spectacular events a combination of component failure and human error is often found. Especially the Rasmussen-Report and the German Risk Assessment Study show for pressurised water reactors that human error must not be underestimated. Although operator errors as a form of human error can never be eliminated entirely, they can be minimized and their effects kept within acceptable limits if a thorough training of personnel is combined with an adequate design of the plant against accidents. Contrary to the investigation of engineering errors, the investigation of human errors has so far been carried out with relatively small budgets. Intensified investigations in this field appear to be a worthwhile effort. (orig.)
Your Lung Operation: After Your Operation
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2007-01-01
... & SOFAs, legal assistance, combating terrorism, domestic operations, noncombatant evacuation operations, special operations, civil affairs, air, sea, and space law, detainee operations, reserve...
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Medical Student Core Curriculum ACS/ASE Medical Student Simulation-Based Surgical Skills Curriculum Cancer Education Cancer Education ... Surgeons Education Patients and Family Skills Programs Your Lung Operation Your Lung Operation DVD After Your Operation ...
Your Lung Operation: After Your Operation
Full Text Available ... Overview ACS-AEI Consortium Quarterly ACS Chapter News Cancer ... American College of Surgeons Education Patients and Family Skills Programs Your Lung Operation Your Lung Operation DVD After Your Operation ...
Your Lung Operation: After Your Operation
Full Text Available ... Liability Surgeons as Advocates Surgeons and Bundled Payment Models Surgeons as Institutional Employees Our Changing Health Care ... Lung Operation After Your Operation Your Discharge and Recovery Complete Video After Your Operation Guidance for after ...
Your Lung Operation: After Your Operation
Full Text Available ... Safety Resources About the Patient Education Program The Recovery Room Choosing Wisely Educational Programs Educational Programs Educational ... Lung Operation After Your Operation Your Discharge and Recovery Complete Video After Your Operation Guidance for after ...
Operator theory, operator algebras and applications
Lebre, Amarino; Samko, Stefan; Spitkovsky, Ilya
2014-01-01
This book consists of research papers that cover the scientific areas of the International Workshop on Operator Theory, Operator Algebras and Applications, held in Lisbon in September 2012. The volume particularly focuses on (i) operator theory and harmonic analysis (singular integral operators with shifts; pseudodifferential operators, factorization of almost periodic matrix functions; inequalities; Cauchy type integrals; maximal and singular operators on generalized Orlicz-Morrey spaces; the Riesz potential operator; modification of Hadamard fractional integro-differentiation), (ii) operator algebras (invertibility in groupoid C*-algebras; inner endomorphisms of some semi group, crossed products; C*-algebras generated by mappings which have finite orbits; Folner sequences in operator algebras; arithmetic aspect of C*_r SL(2); C*-algebras of singular integral operators; algebras of operator sequences) and (iii) mathematical physics (operator approach to diffraction from polygonal-conical screens; Poisson geo...
A Survey on Operator Monotonicity, Operator Convexity, and Operator Means
Pattrawut Chansangiam
2015-01-01
Full Text Available This paper is an expository devoted to an important class of real-valued functions introduced by Löwner, namely, operator monotone functions. This concept is closely related to operator convex/concave functions. Various characterizations for such functions are given from the viewpoint of differential analysis in terms of matrix of divided differences. From the viewpoint of operator inequalities, various characterizations and the relationship between operator monotonicity and operator convexity are given by Hansen and Pedersen. In the viewpoint of measure theory, operator monotone functions on the nonnegative reals admit meaningful integral representations with respect to Borel measures on the unit interval. Furthermore, Kubo-Ando theory asserts the correspondence between operator monotone functions and operator means.
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
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Space station operations management
Cannon, Kathleen V.
1989-01-01
Space Station Freedom operations management concepts must be responsive to the unique challenges presented by the permanently manned international laboratory. Space Station Freedom will be assembled over a three year period where the operational environment will change as significant capability plateaus are reached. First Element Launch, Man-Tended Capability, and Permanent Manned Capability, represent milestones in operational capability that is increasing toward mature operations capability. Operations management concepts are being developed to accomodate the varying operational capabilities during assembly, as well as the mature operational environment. This paper describes operations management concepts designed to accomodate the uniqueness of Space Station Freedoom, utilizing tools and processes that seek to control operations costs.
Multiple Meixner polynomials and non-Hermitian oscillator Hamiltonians
Ndayiragije, François; Van Assche, Walter
2013-01-01
Multiple Meixner polynomials are polynomials in one variable which satisfy orthogonality relations with respect to $r>1$ different negative binomial distributions (Pascal distributions). There are two kinds of multiple Meixner polynomials, depending on the selection of the parameters in the negative binomial distribution. We recall their definition and some formulas and give generating functions and explicit expressions for the coefficients in the nearest neighbor recurrence relation. Followi...
Symmetry breaking in the double-well hermitian matrix models
Brower, R.C.; Deo, N.; Jain, S.; Tan, C.I.
1993-01-01
We study symmetry breaking in Z 2 symmetric large N matrix models. In the planar approximation for both the symmetric double-well φ 4 model and the symmetric Penner model, we find there is an infinite family of broken symmetry solutions characterized by different sets of recursion coefficients R n and S n that all lead to identical free energies and eigenvalue densities. These solutions can be parameterized by an arbitrary angle θ(x), for each value of x=n/N 4 theory the double scaling string equations are parameterized by a conserved angular momentum parameter in the range 0≤l<∞ and a single arbitrary U(1) phase angle. (orig.)
Symmetry breaking in the double-well hermitian matrix models
Brower, R C; Jain, S; Tan, C I; Brower, Richard C.; Deo, Nevidita; Jain, Sanjay; Tan, Chung-I
1993-01-01
We study symmetry breaking in $Z_2$ symmetric large $N$ matrix models. In the planar approximation for both the symmetric double-well $\\phi^4$ model and the symmetric Penner model, we find there is an infinite family of broken symmetry solutions characterized by different sets of recursion coefficients $R_n$ and $S_n$ that all lead to identical free energies and eigenvalue densities. These solutions can be parameterized by an arbitrary angle $\\theta(x)$, for each value of $x = n/N < 1$. In the double scaling limit, this class reduces to a smaller family of solutions with distinct free energies already at the torus level. For the double-well $\\phi^4$ theory the double scaling string equations are parameterized by a conserved angular momentum parameter in the range $0 \\le l < \\infty$ and a single arbitrary $U(1)$ phase angle.
Time-dependent version of crypto-Hermitian quantum theory
Znojil, Miloslav
2008-01-01
Roč. 78, č. 8 (2008), 085003/1-085003/5 ISSN 1550-7998 R&D Projects: GA ČR GA202/07/1307; GA MŠk LC06002 Institutional research plan: CEZ:AV0Z10480505 Keywords : KLEIN-GORDON FIELDS * PSEUDO-HERMITICITY * HILBERT-SPACE Subject RIV: BE - Theoretical Physics Impact factor: 5.050, year: 2008
Scattering theory using smeared non-Hermitian potentials
Znojil, Miloslav
2009-01-01
Roč. 80, č. 4 (2009), 045009/1-045009/12 ISSN 1550-7998 R&D Projects: GA MŠk LC06002; GA ČR GA202/07/1307 Institutional research plan: CEZ:AV0Z10480505 Keywords : symmetric quantum-mechanics * pseudo-hermiticity * real spectrum Subject RIV: BE - Theoretical Physics Impact factor: 4.922, year: 2009
Liu Rong; Yang Shuchun; Peng Jun; Zhou Shoukang
2003-01-01
Experiences and work methods with High Flux Engineering Test Reactor (HFETR) operation are introduced, which have been accumulated in a long period of operation, in the aspects as reactor operation, test, maintenance, operator training and incident management. It's clear that the safety operation of HFETR has been ensured, and the methods are valid. (authors)
... type=”submit” value=”Submit” /> Healthy Water Home Animal Feeding Operations Recommend on Facebook Tweet Share Compartir ... of Concentrated Animal Feeding Operations (CAFOs) What are Animal Feeding Operations (AFOs)? According to the United States ...
Conduct of operations: establishing operational focus and setting operational standards
Lane, L.; McGuigan, K.
1998-01-01
Due to the nature of our business, we have often tended to focus on the technological aspects of the nuclear industry. The focus of this paper is directed towards the importance of addressing the people skills, attitudes, and 'culture' within, and surrounding, our facilities as key areas of improvement. Within Ontario Hydro Nuclear (OLIN) we have developed the terminology 'event free' operation and 'event free' culture. 'Event Free' recognizes errors as a part of human performance. 'Event Free' takes into account human weaknesses, and provides tools (such as standards) to manage, control, and mitigate errors. In essence, 'Event Free' encompasses two concepts: 1. Prevent errors from occurring; 2. If an error is made, catch it before it can affect safe operation of the facility, learn from the error, and ensure that it does not happen again. In addressing these business realities, Ontario Hydro has identified a number of key support mechanisms and corresponding performance standards that are essential for achieving operating excellence and an 'event free' business culture. This paper will discuss two operational aspects of an 'event free' culture, the first being a set of expectations to enhance the culture, and the second an example of cultural change: 1. Operating Standards - establishing clear expectations for human performance in operating staff; 2. Operational Focus - the understanding that, as a nuclear worker, you should consider every task, activity, in fact everything you do in this business, for the potential to affect safe and reliable operation of a nuclear facility. Note that although the term 'Operational' appears in the title, this concept applies to every individual in the nuclear business, from the cleaner, to the Board of Directors, to the external supplier. (author)
Saxton Transportation Operations Laboratory
Federal Laboratory Consortium — The Saxton Transportation Operations Laboratory (Saxton Laboratory) is a state-of-the-art facility for conducting transportation operations research. The laboratory...
Your Lung Operation: After Your Operation
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Separable quadratic stochastic operators
Rozikov, U.A.; Nazir, S.
2009-04-01
We consider quadratic stochastic operators, which are separable as a product of two linear operators. Depending on properties of these linear operators we classify the set of the separable quadratic stochastic operators: first class of constant operators, second class of linear and third class of nonlinear (separable) quadratic stochastic operators. Since the properties of operators from the first and second classes are well known, we mainly study the properties of the operators of the third class. We describe some Lyapunov functions of the operators and apply them to study ω-limit sets of the trajectories generated by the operators. We also compare our results with known results of the theory of quadratic operators and give some open problems. (author)
1998-01-01
In this part the are reviewed: Co-operation with IAEA; Participation of the Slovakia on the 41 st session of the General Conference; The comprehensive Nuclear-Test-Ban Treaty Organization; Co-operation with the Organization for Economic Co-operation and Development; co-operation with the European Commission; Fulfillment of obligations resulting from the international contracting documents
Biomedical programs operations plans
Walbrecher, H. F.
1974-01-01
Operational guidelines for the space shuttle life sciences payloads are presented. An operational assessment of the medical experimental altitude test for Skylab, and Skylab life sciences documentation are discussed along with the operations posture and collection of space shuttle operational planning data.
Sonoda, Hidenori
1992-01-01
We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e. the strong fine structure constant and the quark mass) of QCD in four- dimensional euclidean space. The formula is given as spatial integration of the operator conjugate to a parameter. The operator product of a composite operator and a conjugate operator has an unintegrable part, and the formula requires divergent subtractions. By imposing consistency conditions we drive a relation between the anomalous dimensions of the composite operators and the unintegrable part of the operator product coefficients. (orig.)
Lupton, L.R.; Anderson, L.L.; Basso, R.A.J.
1989-11-01
As CANDU plants become more complex, and are operated under tighter constraints and for longer periods between outages, plant operations staff will have to absorb more information to correctly and rapidly respond to upsets. A development program is underway at AECL to use expert systems and interactive media tools to assist operations staff of existing and future CANDU plants. The complete system for plant information access and display, on-line advice and diagnosis, and interactive operating procedures is called the Operator Companion. A prototype, consisting of operator consoles, expert systems and simulation modules in a distributed architecture, is currently being developed to demonstrate the concepts of the Operator Companion
Elementary operators on self-adjoint operators
Molnar, Lajos; Semrl, Peter
2007-03-01
Let H be a Hilbert space and let and be standard *-operator algebras on H. Denote by and the set of all self-adjoint operators in and , respectively. Assume that and are surjective maps such that M(AM*(B)A)=M(A)BM(A) and M*(BM(A)B)=M*(B)AM*(B) for every pair , . Then there exist an invertible bounded linear or conjugate-linear operator and a constant c[set membership, variant]{-1,1} such that M(A)=cTAT*, , and M*(B)=cT*BT, .
Watanabe, Takashi; Odakawa, Naoto; Erikuchi, Makoto; Okada, Masayuki; Koizumi, Atsuhiko.
1996-01-01
The device of the present invention provides a device suitable for monitoring a reactor core state and operation replanning in terms of reactor operation. Namely, (1) an operation result difference judging means judges that replanning is necessary when the operation results deviates from the operation planning, (2) an operation replanning rule data base storing means stores a deviation key which shows various kinds of states where the results deviate from the planning and a rule for replanning for returning to the operation planning on every deviating key, (3) an operation replanning means forms a new operation planning in accordance with the rule which is retrieved based on the deviation key, (4) an operation planning optimizing rule data base storing means evaluates the reformed planning and stores it on every evaluation item, (5) an operation planning optimization means correct the operation planning data so as to be optimized when the evaluation of the means (4) is less than a reference value, and (6) an operation planning display means edits adaptable operation planning data and the result of the evaluation and displays them. (I.S.)
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
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Nonlocal Operational Calculi for Dunkl Operators
Ivan H. Dimovski
2009-03-01
Full Text Available The one-dimensional Dunkl operator $D_k$ with a non-negative parameter $k$, is considered under an arbitrary nonlocal boundary value condition. The right inverse operator of $D_k$, satisfying this condition is studied. An operational calculus of Mikusinski type is developed. In the frames of this operational calculi an extension of the Heaviside algorithm for solution of nonlocal Cauchy boundary value problems for Dunkl functional-differential equations $P(D_ku = f$ with a given polynomial $P$ is proposed. The solution of these equations in mean-periodic functions reduces to such problems. Necessary and sufficient condition for existence of unique solution in mean-periodic functions is found.
Your Lung Operation: After Your Operation
Full Text Available ... Mentoring for Excellence in Trauma Surgery Advanced Trauma Life Support Verification, Review, and Consultation Program for Hospitals ... Surgical Skills for Exposure in Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills ...
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Disaster Management and Emergency Preparedness Rural Trauma Team Development Course Trauma Evaluation and Management Trauma CME The ... for after the operation including review of attached equipment and ways for you to actively participate to ...
Your Lung Operation: After Your Operation
Full Text Available ... Up to Date with ACS Association Management JACS Jobs Events Find a Surgeon Patients and Family Contact My Profile Shop ( 0 ) Cart Donate American College of Surgeons Education Patients and Family Skills Programs Your Lung Operation ...
Your Lung Operation: After Your Operation
Full Text Available ... ACS ACS and Veterans Diversity at ACS ... and Family Contact My Profile Shop ( 0 ) Cart Donate American College of Surgeons Education Patients and Family Skills Programs Your Lung Operation ...
Your Lung Operation: After Your Operation
Full Text Available ... Online Guide to Choosing a Surgical Residency Practice Management Workshops Patients and Family Patient Education Patient Education ... Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills for Trauma Disaster Management and ...
Improving operating room safety
Garrett Jill
2009-11-01
Full Text Available Abstract Despite the introduction of the Universal Protocol, patient safety in surgery remains a daily challenge in the operating room. This present study describes one community health system's efforts to improve operating room safety through human factors training and ultimately the development of a surgical checklist. Using a combination of formal training, local studies documenting operating room safety issues and peer to peer mentoring we were able to substantially change the culture of our operating room. Our efforts have prepared us for successfully implementing a standardized checklist to improve operating room safety throughout our entire system. Based on these findings we recommend a multimodal approach to improving operating room safety.
Computer algebra and operators
Fateman, Richard; Grossman, Robert
1989-01-01
The symbolic computation of operator expansions is discussed. Some of the capabilities that prove useful when performing computer algebra computations involving operators are considered. These capabilities may be broadly divided into three areas: the algebraic manipulation of expressions from the algebra generated by operators; the algebraic manipulation of the actions of the operators upon other mathematical objects; and the development of appropriate normal forms and simplification algorithms for operators and their actions. Brief descriptions are given of the computer algebra computations that arise when working with various operators and their actions.
Jaeger, Trent
2008-01-01
Operating systems provide the fundamental mechanisms for securing computer processing. Since the 1960s, operating systems designers have explored how to build "secure" operating systems - operating systems whose mechanisms protect the system against a motivated adversary. Recently, the importance of ensuring such security has become a mainstream issue for all operating systems. In this book, we examine past research that outlines the requirements for a secure operating system and research that implements example systems that aim for such requirements. For system designs that aimed to
Yoshimura, Sadanori.
1994-01-01
The device of the present invention evaluates the propriety of an operation which is conducted optionally by a trainee depending on the state of the plant, analyzes the cause of an operation error and aids the preparation of training policy and teaching materials based on the results of the evaluation and the analysis. Namely, an operation data collection device collects operation data for the plant operation conducted by the trainee and the state of the plant during the operation. Since an operation evaluation device evaluates the plant operation in a short period of time based on the evaluation criteria of an operation evaluation knowledge base, an operation error is never overlooked. Accordingly, uniform and highly reliable operation training at definite evaluation criteria can be obtained. In addition, an error-cause analyzing device and a training policy knowledge base analyze the cause of an error inherent to each of the trainee, and it is recorded systematically independently on every trainees. Since a training policy guide device retrieves and presents an operation error and a cause of the error, there can be prepared a training policy incorporating training with respect to the operation error that each of the trainee tends to commit. (I.S.)
Oliva, N [Ontario Hydro, Toronto, ON (Canada)
1997-12-01
Safe Operating Envelope is described representing: The outer bound of plant conditions within which day-to-day plant operation must be maintained in order to comply with regulatory requirements, associated safety design criteria and corporate nuclear safety goals. Figs.
Major operations and activities
Black, D.G.
1995-06-01
This section of the 1994 Hanford Site Environmental Report summarizes the major operations and activities on the site. These operations and activities include site management, waste management, environmental restoration and corrective actions, and research and technology development.
Autonomous Systems and Operations
National Aeronautics and Space Administration — The AES Autonomous Systems and Operations (ASO) project will develop an understanding of the impacts of increasing communication time delays on mission operations,...
Heselton, Ken
2004-01-01
Containing key information for operators and managers of large and small plants, this is an indispensable guide for those at advanced and early stages of their careers, as well as for managers interested in reducing operating expenses.
2006-01-01
.... It sets forth joint doctrine to govern the joint operation planning activities and performance of the Armed Forces of the United States in joint operations, and provides the joint doctrinal basis...
Crew Transportation Operations Standards
Mango, Edward J.; Pearson, Don J. (Compiler)
2013-01-01
The Crew Transportation Operations Standards contains descriptions of ground and flight operations processes and specifications and the criteria which will be used to evaluate the acceptability of Commercial Providers' proposed processes and specifications.
Oliva, N.
1997-01-01
Safe Operating Envelope is described representing: The outer bound of plant conditions within which day-to-day plant operation must be maintained in order to comply with regulatory requirements, associated safety design criteria and corporate nuclear safety goals. Figs
Major operations and activities
Black, D.G.
1995-01-01
This section of the 1994 Hanford Site Environmental Report summarizes the major operations and activities on the site. These operations and activities include site management, waste management, environmental restoration and corrective actions, and research and technology development
National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...
Ranking Operations Management conferences
Steenhuis, H.J.; de Bruijn, E.J.; Gupta, Sushil; Laptaned, U
2007-01-01
Several publications have appeared in the field of Operations Management which rank Operations Management related journals. Several ranking systems exist for journals based on , for example, perceived relevance and quality, citation, and author affiliation. Many academics also publish at conferences
Emergency operation determination system
Miki, Tetsushi.
1993-01-01
The system of the present invention can determine an emergency operation coping with abnormal events occurring during nuclear plant operation without replying on an operator's judgement. That is, the system of the present invention comprises an intelligence base which divides and classifies the aims of the plant operation for the function, structure and operation manual and puts them into network. Degree of attainment for the extend of the status normality is determined on every aim of operation based on various kinds of measured data during plant operation. For a degree of attainment within a predetermined range, it is judged that an emergency operation is possible although this is in an abnormal state. Degree of emergency is determined by a fuzzy theory based on the degree of attainment, variation coefficient for the degree of attainment and the sensitivity to external disturbance as parameters. Priority for the degree of emergency on every operation aims is determined by comparison. Normality is successively checked for the determined operation aims. As a result, equipments as objects of abnormality suppressing operation are specified, and the operation amount of the equipments as objects are determined so that the measuring data are within a predetermined range. (I.S.)
Vipin Kamboj; Hitesh Gupta
2012-01-01
Mobile phones are used by every people in today’s life. We use mobile phones without knowing the different factors that a mobile used including its technology, operating system, CPU ,RAM etc. Many types of operating system are used by different mobile. Every operating system has their advantage
Satoh, Kotaro
1990-01-01
The present status of the TRISTAN operation is summarized mainly after the installation of superconducting cavities in the 1988 summer shutdown. The paper describes the initial experience of the superconducting cavity operation, the colliding operation at 30.4 GeV and the beam injection. Future improvement is also reported. (author)
Operations and maintenance philosophy
DUNCAN, G.P.
1999-01-01
This Operations and Maintenance (O and M) Philosophy document is intended to establish a future O and M vision, with an increased focus on minimizing worker exposure, ensuring uninterrupted retrieval operations, and minimizing operation life-cycle cost. It is intended that this document would incorporate O and M lessons learned into on-going and future project upgrades
Grenet, G.; Kibler, M.
1978-06-01
A closed polynomial formula for the qth component of the diagonal operator equivalent of order k is derived in terms of angular momentum operators. The interest in various fields of molecular and solid state physics of using such a formula in connection with symmetry adapted operator equivalents is outlined
Lageos assembly operation plan
Brueger, J.
1975-01-01
Guidelines and constraints procedures for LAGEOS assembly, operation, and design performance are given. Special attention was given to thermal, optical, and dynamic analysis and testing. The operation procedures illustrate the interrelation and sequence of tasks in a flow diagram. The diagram also includes quality assurance functions for verification of operation tasks.
Operational Intelligence and Operational Design: Thinking about Operational Art
2011-06-01
captured it best when he wrote, ―Operational intelligence is more or less the fusion of 45 Kent... Market Garden….‖34 Additionally, Drea concluded that the strong-minded General Douglas MacArthur‘s ―sense of destiny‖ shaped his strategic concepts...1960. Memorandum RM-4172-ISA, Santa Monica, CA: The RAND Corporation, September 1964. The Bible . New International Version. Hitchcock, Walter T., ed
Operational symmetries basic operations in physics
Saller, Heinrich
2017-01-01
This book describes the endeavour to relate the particle spectrum with representations of operational electroweak spacetime, in analogy to the atomic spectrum as characterizing representations of hyperbolic space. The spectrum of hyperbolic position space explains the properties of the nonrelativistic atoms; the spectrum of electroweak spacetime is hoped to explain those of the basic interactions and elementary particles. In this book, the theory of operational symmetries is developed from the numbers, from Plato’s and Kepler’s symmetries over the simple Lie groups to their applications in nonrelativistic, special relativistic and general relativistic quantum theories with the atomic spectrum for hyperbolic position and, in first attempts, the particle spectrum for electroweak spacetime. The standard model of elementary particles and interactions is characterized by a symmetry group. In general, as initiated by Weyl and stressed by Heisenberg, quantum theory can be built as a theory of operation groups an...
Shuttle operations era planning for flight operations
Holt, J. D.; Beckman, D. A.
1984-01-01
The Space Transportation System (STS) provides routine access to space for a wide range of customers in which cargos vary from single payloads on dedicated flights to multiple payloads that share Shuttle resources. This paper describes the flight operations planning process from payload introduction through flight assignment to execution of the payload objectives and the changes that have been introduced to improve that process. Particular attention is given to the factors that influence the amount of preflight preparation necessary to satisfy customer requirements. The partnership between the STS operations team and the customer is described in terms of their functions and responsibilities in the development of a flight plan. A description of the Mission Control Center (MCC) and payload support capabilities completes the overview of Shuttle flight operations.
Operator licensing examiner standards
1993-01-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Use Patient Opioid Use Position Statements and Task Force Patient Education Initiatives Advocacy and Health Policy Updates Selected Research ... at ACS ACS and Veterans Diversity at ACS ... and Family Contact My Profile Shop ( 0 ) Cart Donate American College of Surgeons Education Patients and Family Skills Programs Your Lung Operation ...
Brandli, A. E.; Eckelkamp, R. E.; Kelly, C. M.; Mccandless, W.; Rue, D. L.
1990-01-01
The objective of an operations management system is to provide an orderly and efficient method to operate and maintain aerospace vehicles. Concepts are described for an operations management system and the key technologies are highlighted which will be required if this capability is brought to fruition. Without this automation and decision aiding capability, the growing complexity of avionics will result in an unmanageable workload for the operator, ultimately threatening mission success or survivability of the aircraft or space system. The key technologies include expert system application to operational tasks such as replanning, equipment diagnostics and checkout, global system management, and advanced man machine interfaces. The economical development of operations management systems, which are largely software, will require advancements in other technological areas such as software engineering and computer hardware.
1988-01-01
The Nuclear Waste Policy Act of 1982 assigned to the Department of Energy's (DOE) Office of Civilian Waste Management the responsibility for disposing of high-level waste and spent fuel. A significant part of that responsibility involves transporting nuclear waste materials within the federal waste management system; that is, from the waste generator to the repository. The lead responsibility for transportation operations has been assigned to Oak Ridge Operations, with Oak Ridge National Laboratory (ORNL) providing technical support through the Transportation Operations Support Task Group. One of the ORNL support activities involves assessing what facilities, equipment and services are required to assure that an acceptable, cost-effective and safe transportation operations system can be designed, operated and maintained. This study reviews, surveys and assesses the experience of Nuclear Assurance Corporation (NAC) in operating a fleet of spent-fuel shipping casks to aid in developing the spent-fuel transportation system
Entanglement branching operator
Harada, Kenji
2018-01-01
We introduce an entanglement branching operator to split a composite entanglement flow in a tensor network which is a promising theoretical tool for many-body systems. We can optimize an entanglement branching operator by solving a minimization problem based on squeezing operators. The entanglement branching is a new useful operation to manipulate a tensor network. For example, finding a particular entanglement structure by an entanglement branching operator, we can improve a higher-order tensor renormalization group method to catch a proper renormalization flow in a tensor network space. This new method yields a new type of tensor network states. The second example is a many-body decomposition of a tensor by using an entanglement branching operator. We can use it for a perfect disentangling among tensors. Applying a many-body decomposition recursively, we conceptually derive projected entangled pair states from quantum states that satisfy the area law of entanglement entropy.
Gheorghe BASANU; Georgiana NUKINA
2011-01-01
The Management of port operation requires the proper and efficient use of port facility, equipment for cargo handling, berth facilities, waterways and roads. It also entails the use of effective communications system, storage facilities, and dockworkers. The whole activities mentioned above form the bulk of port operations. The aspiration of port operator is to get cargo through the gateway of ports as fast as possible on to other modes of transport (rail or road) with a minimal cost to them ...
Marella, J.R.
1995-01-01
A determination of minimum requirements for purge exhaust ventilation system operability has been performed. HLWE and HLW Regulatory Program personnel have evaluated the various scenarios of equipment conditions and HLWE has developed the requirements for purge exhaust systems. This report is provided to document operability requirements to assist Tank Farm personnel to determine whether a system is operable/inoperable and to define required compensatory actions
Operation Chromite: Amphibious Planning
2005-01-01
tut present Tutorial Presentation Interactive Media Element This interactive tutorial covers the Inchon landing case study that provides several good examples of the types of decisions made during the amphibious planning process, and how they compare to the current matrix of the ten primary decisions for amphibious operation required today by joint doctrine. Operation Chromite is used as an example. 8808A Warfighting from the Sea: Amphibious Operations
1985-01-01
Long-term and short-term objectives for the development of a network operating system for the Space Station are stated. The short-term objective is to develop a prototype network operating system for a 100 megabit/second fiber optic data bus. The long-term objective is to establish guidelines for writing a detailed specification for a Space Station network operating system. Major milestones are noted. Information is given in outline form.
2014-06-01
19th floor of a Hotel to overlook the entire event. Page 12 of 17 Figure 6: The SPF Operations Centre overlooking the Event Lessons...have a cheap system to help them solve their immediate operational needs. b. Medium enterprises, that need to have quick customization of the...Optimize” tools to help them advance their current operations to a higher service satisfaction level seen by the public. 32. Common across all
Strategic Psychological Operations management
Sokoloski, Joseph A.
2005-01-01
United States Military Psychological Operations are engaged in a type of mass marketing of ideas. To accomplish this The United States Army Civil Affairs and Psychological Operations Command (USACAPOC) employs active and reserve PSYOP units to conduct PSYOP campaigns. However the methodology used to manage these campaigns often hinders the effective employment of timely and effective Psychological Operations. PSYOP has a difficult job to accomplish but PSYOP does not have the proper managemen...
1989-11-01
The US Nuclear Regulatory Commission's monthly Licensed Operating Reactors Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. Since all of the data concerning operation of the units is provided by the utility operators less than two weeks after the end of the month, necessary corrections to published information are shown on the errata page
Miscellaneous Industrial Mineral Operations
Department of Homeland Security — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...
2007-01-01
...), human rights, rules of engagement, emergency essential civilians supporting military operations, contingency contractor personnel, foreign and deployment, criminal law, environmental law, fiscal law...
Wiebe, J S
1997-09-01
The presentation briefly considers the following aspects concerning enhancing operational safety of NPP: licensed control room supervision, reactivity changes, personnel access to control room, simulator training.
Operational safety reliability research
Hall, R.E.; Boccio, J.L.
1986-01-01
Operating reactor events such as the TMI accident and the Salem automatic-trip failures raised the concern that during a plant's operating lifetime the reliability of systems could degrade from the design level that was considered in the licensing process. To address this concern, NRC is sponsoring the Operational Safety Reliability Research project. The objectives of this project are to identify the essential tasks of a reliability program and to evaluate the effectiveness and attributes of such a reliability program applicable to maintaining an acceptable level of safety during the operating lifetime at the plant
Operational Modal Analysis Tutorial
Brincker, Rune; Andersen, Palle
of modal parameters of practical interest - including the mode shape scaling factor - with a high degree of accuracy. It is also argued that the operational technology offers the user a number of advantages over traditional modal testing. The operational modal technology allows the user to perform a modal......In this paper the basic principles in operational modal testing and analysis are presented and discussed. A brief review of the techniques for operational modal testing and identification is presented, and it is argued, that there is now a wide range of techniques for effective identification...
1990-04-01
The Operating Units Status Report --- Licensed Operating Reactors provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management from the Headquarters staff on NRC's Office of Enforcement (OE), from NRC's Regional Offices, and from utilities. The three sections of the report are: monthly highlights and statistics for commercial operating units, and errata from previously reported data; a compilation of detailed information on each unit, provided by NRC's Regional Offices, OE Headquarters and the utilities; and an appendix for miscellaneous information such as spent fuel storage capability, reactor-years of experience and non- power reactors in the US
Klinda, J.; Lieskovska, Z.
1998-01-01
Within the Union Nations (UN) framework, the Slovak Republic participated in following activities on environment protection co-operation: UN European Economic Commission, UN Industrial Development Organization, UN Development Programme, UN Human Habitat Organization, UN Environment Programme, and UN Commission on Sustainable Development. Relevant activities of the Slovak Republic in these co-operations as well as in European Union and OECD activities are reviewed. International conventions and other forms of multilateral co-operation, bilateral co-operation, and international programmes and projects in which the Slovak Republic took participate are presented
Operator interface for vehicles
Bissontz, Jay E
2015-03-10
A control interface for drivetrain braking provided by a regenerative brake and a non-regenerative brake is implemented using a combination of switches and graphic interface elements. The control interface comprises a control system for allocating drivetrain braking effort between the regenerative brake and the non-regenerative brake, a first operator actuated control for enabling operation of the drivetrain braking, and a second operator actuated control for selecting a target braking effort for drivetrain braking. A graphic display displays to an operator the selected target braking effort and can be used to further display actual braking effort achieved by drivetrain braking.
Operator licensing examiner standards
1987-05-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes
Gyroaveraging operations using adaptive matrix operators
Dominski, Julien; Ku, Seung-Hoe; Chang, Choong-Seock
2018-05-01
A new adaptive scheme to be used in particle-in-cell codes for carrying out gyroaveraging operations with matrices is presented. This new scheme uses an intermediate velocity grid whose resolution is adapted to the local thermal Larmor radius. The charge density is computed by projecting marker weights in a field-line following manner while preserving the adiabatic magnetic moment μ. These choices permit to improve the accuracy of the gyroaveraging operations performed with matrices even when strong spatial variation of temperature and magnetic field is present. Accuracy of the scheme in different geometries from simple 2D slab geometry to realistic 3D toroidal equilibrium has been studied. A successful implementation in the gyrokinetic code XGC is presented in the delta-f limit.
Operational Transformation In Co-Operative Editing
Mandeep Kaur
2015-08-01
Full Text Available Cooperative Editing Systems in real-time allows a virtual team to view and edit a shared document at the same time. The document shared must be synchronized in order to ensure consistency for all the participants. This paper describes the Operational Transformation the evolution of its techniques its various applications major issues and achievements. In addition this paper will present working of a platform where two users can edit a code programming file at the same time.
Operator interface programs for KSTAR operation
Lee, Sangil; Park, Mikyung; Park, Jinseop; Na, Hoonkyun; Kwon, M.
2013-01-01
Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system
Operator interface programs for KSTAR operation
Lee, Sangil, E-mail: leesi@nfri.re.kr; Park, Mikyung, E-mail: mkpark@nfri.re.kr; Park, Jinseop, E-mail: linupark@nfri.re.kr; Na, Hoonkyun, E-mail: hkna@nfri.re.kr; Kwon, M., E-mail: kwonm@nfri.re.kr
2013-11-15
Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system.
Marine Corps Inst., Washington, DC.
Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on crane and excavator operation is designed to enable the crane and excavator operator to perform his/her duties more proficiently. Introductory materials include specific information for MCI students, a course introduction, and a study guide…
Squibb, Gael F.
1984-10-01
The operation teams for the Infrared Astronomical Satellite (IRAS) included scientists from the IRAS International Science Team. The scientific decisions on an hour-to-hour basis, as well as the long-term strategic decisions, were made by science team members. The IRAS scientists were involved in the analysis of the instrument performance, the analysis of the quality of the data, the decision to reacquire data that was contaminated by radiation effects, the strategy for acquiring the survey data, and the process for using the telescope for additional observations, as well as the processing decisions required to ensure the publication of the final scientific products by end of flight operations plus one year. Early in the project, two science team members were selected to be responsible for the scientific operational decisions. One, located at the operations control center in England, was responsible for the scientific aspects of the satellite operations; the other, located at the scientific processing center in Pasadena, was responsible for the scientific aspects of the processing. These science team members were then responsible for approving the design and test of the tools to support their responsibilities and then, after launch, for using these tools in making their decisions. The ability of the project to generate the final science data products one year after the end of flight operations is due in a large measure to the active participation of the science team members in the operations. This paper presents a summary of the operational experiences gained from this scientific involvement.
Health care operations management
Carter, M.W.; Hans, Elias W.; Kolisch, R.
2012-01-01
Health care operations management has become a major topic for health care service providers and society. Operations research already has and further will make considerable contributions for the effective and efficient delivery of health care services. This special issue collects seven carefully
Joint Newspaper Operating Agreements.
Parsons, Marie
The number of competing daily newspapers in American cities has dwindled until only about 50 cities boast two papers. Of the newspapers in those cities, 23 now maintain separate editorial operations but have joint printing, advertising, and circulation departments. The concept of joint operation is 50 years old, dating from the Depression years…
South Carolina State Dept. of Education, Columbia. Office of Vocational Education.
This module on special operations, one in a series dealing with industrial sewing machines, their attachments, and operation, covers two topics: topstitching and mitering. For each topic these components are provided: an introduction, directions, an objective, learning activities, student information, a student self-check, and a check-out…
) NCO Organizational Chart NOAA's Weather and Climate Operational Supercomputing System is known as Climate Climate Prediction Climate Archives Weather Safety Storm Ready NOAA Central Library Photo Library NCO's MISSION * Execute the NCEP operational model suite - Create climate, weather, ocean, space and
First page Back Continue Last page Overview Graphics. Reliance Cell Operator. Reliance was the only bidder for cellular licences for Assam and NE. Services allowed only in Guwahati and Shillong due to “security reasons”. Only major cities in the country with only one operator.
Characteristics of operating pipelines
Gallyamov, A K; Armenskii, E A; Gimaev, R G; Mastobaev, B N; Shammazov, A M
1977-04-01
The interval in pressure changes according to operational data for the Kamennyi Log--Perm oil pipeline was determined with the aid of the pattern identification method. This has made it possible to determine pressure changes in the operational process. 2 references, 1 table.
McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.
1982-03-01
The CANDU Pressurized Heavy Water (CANDU-PHW) type of nuclear electric generating station has been developed jointly by Atomic Energy of Canada Limited and Ontario Hydro. This paper highlights Ontario Hydro's operating experience using the CANDU-PHW system, with a focus on the operating performance and costs, reliability of system components and nuclear safety considerations both to the workers and the public
Basic Sewage Treatment Operation.
Ontario Ministry of the Environment, Toronto.
This manual was developed for use at workshops designed to introduce operators to the fundamentals of sewage plant operation. The course consists of lecture-discussions and hands-on activities. Each of the lessons has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in…
Hans, Elias W.; Nieberg, T.
2007-01-01
The operating room (OR) department of a hospital forms the heart of the organization, where the single largest cost is incurred. This document presents and reports on the “Operating Room Manager Game,” developed to give insight into managing a large hospital's OR department at various levels of
Operation auxiliary system (SAO)
Lolich, J.; Santome, D.; Drexler, J.
1990-01-01
This work presents an auxiliary system for nuclear power plants operation (SAO). The development purpose consisted in a computing supervision system to be installed at different sites of a reactor, mainly in the control room. The inclusion of this system to a nuclear power plant minimizes the possibility of human error for the facility operation. (Author) [es
Administrator
placed in terms of the levels of war, according to contemporary doctrine. .... operations and for the administration of such operations for extended periods. ... view is supported by a recent publication by Vego, professor in Military History at .... with short-term and contingency planning in which the tasks that are executed are.
Decreton, M.
1998-01-01
Maintenance, repair, and dismantling operations in nuclear facilities have to be performed remotely when high radiation doses exclude hands-on operation, but also to minimize contamination risks and occupational doses to the operators. Computer-aided and sensor-based tele-operation enhances safety, reliability, and performance by helping the operator in difficult tasks with poor remote environmental perception. The objectives of work in this domain are to increase the scientific knowledge of the studied phenomena, to improve the interpretation of data, to improve the piloting og experimental devices during irradiation, to reveal and to understand possible unexpected phenomena occurring during irradiation. This scientific report describes the achievements for 1997 in the area of radiation tolerance for of remote-sensing, optical fibres and optical fibre sensors
Gardner, Richard J.; Kiderlen, Markus
A structural theory of operations between real-valued (or extended-real-valued) functions on a nonempty subset A of Rn is initiated. It is shown, for example, that any operation ∗ on a cone of functions containing the constant functions, which is pointwise, positively homogeneous, monotonic......, and associative, must be one of 40 explicitly given types. In particular, this is the case for operations between pairs of arbitrary, or continuous, or differentiable functions. The term pointwise means that (f ∗g)(x) = F(f(x), g(x)), for all x ∈ A and some function F of two variables. Several results in the same...... spirit are obtained for operations between convex functions or between support functions. For example, it is shown that ordinary addition is the unique pointwise operation between convex functions satisfying the identity property, i.e., f ∗ 0 = 0 ∗ f = f, for all convex f, while other results classify Lp...
Aircraft operations management manual
1992-01-01
The NASA aircraft operations program is a multifaceted, highly diverse entity that directly supports the agency mission in aeronautical research and development, space science and applications, space flight, astronaut readiness training, and related activities through research and development, program support, and mission management aircraft operations flights. Users of the program are interagency, inter-government, international, and the business community. This manual provides guidelines to establish policy for the management of NASA aircraft resources, aircraft operations, and related matters. This policy is an integral part of and must be followed when establishing field installation policy and procedures covering the management of NASA aircraft operations. Each operating location will develop appropriate local procedures that conform with the requirements of this handbook. This manual should be used in conjunction with other governing instructions, handbooks, and manuals.
Sustainable Building Operation
Jensen, Jesper Ole
2009-01-01
of sustainable building operation and a survey amongst building administrators from the private and the social housing sector. Our results show that there are many good examples on sustainable building operation in Danish housing estates, where local building managers, residents etc. have gained impressive......Energy-savings in the existing building stock have becomes a main goal in national and international policies. Often focus is on building-renovations, whereas the potential of sustainable building operation to a large extent has been neglected. Nevertheless, international research as well...... as practical experiences from Danish housing estates indicates that there are large potentials for energy savings by focusing on the operation of the buildings. We suggest that in order to achieve sustainability in the existing housing, renovation and operations should be seen as integrated parts...
Noncommutative operational calculus
Henry E. Heatherly
1999-12-01
Full Text Available Oliver Heaviside's operational calculus was placed on a rigorous mathematical basis by Jan Mikusinski, who constructed an algebraic setting for the operational methods. In this paper, we generalize Mikusi'{n}ski's methods to solve linear ordinary differential equations in which the unknown is a matrix- or linear operator-valued function. Because these functions can be zero-divisors and do not necessarily commute, Mikusi'{n}ski's one-dimensional calculus cannot be used. The noncommuative operational calculus developed here,however, is used to solve a wide class of such equations. In addition, we provide new proofs of existence and uniqueness theorems for certain matrix- and operator valued Volterra integral and integro-differential equations. Several examples are given which demonstrate these new methods.
Assessing Operational Situations
Zhang, Xinxin
In spite of the high level of automation commonly applied to today’s engineering system, humans’ skill and knowledge still plays a central role in the systems’ daily operation, critical decision making, and accident management. The complexity of the engineered system poses great challenge for human...... operators to perceive and understand the operational situation. The research domain of situation awareness approaches the operational challenges from the human cognition perspective while the presented thesis aims at supporting situation assessment from the system perspective. The thesis has reviewed...... different perspectives on situation awareness in the human factor studies and uses the knowledge reflectively for system representation and analysis. The human cognitive activities during complex plant operation and how they perceive a situation and what kind of knowledge has to be established in the human...
Tanenbaum, Andrew S
2015-01-01
Modern Operating Systems, Fourth Edition, is intended for introductory courses in Operating Systems in Computer Science, Computer Engineering, and Electrical Engineering programs. It also serves as a useful reference for OS professionals ' The widely anticipated revision of this worldwide best-seller incorporates the latest developments in operating systems (OS) technologies. The Fourth Edition includes up-to-date materials on relevant'OS. Tanenbaum also provides information on current research based on his experience as an operating systems researcher. ' Modern Operating Systems, Third Editionwas the recipient of the 2010 McGuffey Longevity Award. The McGuffey Longevity Award recognizes textbooks whose excellence has been demonstrated over time.'http://taaonline.net/index.html " Teaching and Learning Experience This program will provide a better teaching and learning experience-for you and your students. It will help: ' *Provide Practical Detail on the Big Picture Concepts: A clear and entertaining writing s...
Integrated formal operations plan
Cort, G.; Dearholt, W.; Donahue, S.; Frank, J.; Perkins, B.; Tyler, R.; Wrye, J.
1994-01-05
The concept of formal operations (that is, a collection of business practices to assure effective, accountable operations) has vexed the Laboratory for many years. To date most attempts at developing such programs have been based upon rigid, compliance-based interpretations of a veritable mountain of Department of Energy (DOE) orders, directives, notices, and standards. These DOE dictates seldom take the broad view but focus on highly specialized programs isolated from the overall context of formal operations. The result is a confusing array of specific, and often contradictory, requirements that produce a patchwork of overlapping niche programs. This unnecessary duplication wastes precious resources, dramatically increases the complexity of our work processes, and communicates a sense of confusion to our customers and regulators. Coupled with the artificial divisions that have historically existed among the Laboratory`s formal operations organizations (quality assurance, configuration management, records management, training, etc.), this approach has produced layers of increasingly vague and complex formal operations plans, each of which interprets its parent and adds additional requirements of its own. Organizational gridlock ensues whenever an activity attempts to implement these bureaucratic monstrosities. The integrated formal operations plan presented is to establish a set of requirements that must be met by an integrated formal operations program, assign responsibilities for implementation and operation of the program, and specify criteria against which the performance of the program will be measured. The accountable line manager specifies the items, processes, and information (the controlled elements) to which the formal operations program specified applies. The formal operations program is implemented using a graded approach based on the level of importance of the various controlled elements and the scope of the activities in which they are involved.
Gohberg, Israel
2001-01-01
rii application of linear operators on a Hilbert space. We begin with a chapter on the geometry of Hilbert space and then proceed to the spectral theory of compact self adjoint operators; operational calculus is next presented as a nat ural outgrowth of the spectral theory. The second part of the text concentrates on Banach spaces and linear operators acting on these spaces. It includes, for example, the three 'basic principles of linear analysis and the Riesz Fredholm theory of compact operators. Both parts contain plenty of applications. All chapters deal exclusively with linear problems, except for the last chapter which is an introduction to the theory of nonlinear operators. In addition to the standard topics in functional anal ysis, we have presented relatively recent results which appear, for example, in Chapter VII. In general, in writ ing this book, the authors were strongly influenced by re cent developments in operator theory which affected the choice of topics, proofs and exercises. One ...
Computerized operator decision aids
Long, A.B.
1984-01-01
This article explores the potential benefits associated with the use of computers in nuclear plants by the operating crew as an aid in making decisions. Pertinent findings are presented from recently completed projects to establish the context in which operating decisions have to be made. Key factors influencing the decision-making process itself are also identified. Safety parameter display systems, which are being implemented in various forms by the nuclear industry, are described within the context of decision making. In addition, relevant worldwide research and development activities are examined as potential enhancements to computerized operator decision aids to further improve plant safety and availability
Operational proof of automation
Jaerschky, R.; Reifenhaeuser, R.; Schlicht, K.
1976-01-01
Automation of the power plant process may imply quite a number of problems. The automation of dynamic operations requires complicated programmes often interfering in several branched areas. This reduces clarity for the operating and maintenance staff, whilst increasing the possibilities of errors. The synthesis and the organization of standardized equipment have proved very successful. The possibilities offered by this kind of automation for improving the operation of power plants will only sufficiently and correctly be turned to profit, however, if the application of these technics of equipment is further improved and if its volume is tallied with a definite etc. (orig.) [de
Tevatron operational experiences
Norris, B.L.; Theilacker, J.C.
1989-02-01
Fermilabs superconducting accelerator, the Tevatron has been operational for nearly six years. The history of its operation is presented. Several long shutdowns for superconducting dipole repairs are discussed. The dominant factor influencing the repair was conductor motion which fatigued the cable in the magnet ends. Borescoping and x-raying techniques were used to determine which magnet ends required repair. Detailed downtime logs were kept for each of the running periods. A discussion of the sources of downtime and a comparison for different operating modes is presented
Lee, Young Jae; Lee, Hae Cho; Lee, Ho Yeun; Kim, Young Taek; Lee, Sung Kyu; Park, Jeong Suk; Nam, Ji Wha; Kim, Soon Kon; Yang, Sung Un; Sohn, Jae Min; Moon, Soon Sung; Park, Bong Sik; Lee, Byung Heon; Park, Sun Hee; Kim, Jin Hee; Hwang, Hyeoi Sun; Lee, Hee Ja; Hwang, In A.
1993-12-01
The report described the operation and the trouble shooting of main computer and KAERINet. The results of the project are as follows; 1. The operation and trouble shooting of the main computer system. (Cyber 170-875, Cyber 960-31, VAX 6320, VAX 11/780). 2. The operation and trouble shooting of the KAERINet. (PC to host connection, host to host connection, file transfer, electronic-mail, X.25, CATV etc.). 3. The development of applications -Electronic Document Approval and Delivery System, Installation the ORACLE Utility Program. 22 tabs., 12 figs. (Author) .new
McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.; Thurygill, E.W.
1980-05-01
The CANDU-PHW program is based upon 38 years of heavy water reactor experience with 35 years of operating experience. Canada has had 72 reactor years of nuclear-electric operations experience with 10 nuclear units in 4 generating stations during a period of 18 years. All objectives have been met with outstanding performance: worker safety, public safety, environmental emissions, reliable electricity production, and low electricity cost. The achievement has been realized through total teamwork involving all scientific disciplines and all project functions (research, design, manufacturing, construction, and operation). (auth)
Lee, Young Jae; Lee, Hae Cho; Lee, Ho Yeun; Kim, Young Taek; Lee, Sung Kyu; Park, Jeong Suk; Nam, Ji Wha; Kim, Soon Kon; Yang, Sung Un; Sohn, Jae Min; Moon, Soon Sung; Park, Bong Sik; Lee, Byung Heon; Park, Sun Hee; Kim, Jin Hee; Hwang, Hyeoi Sun; Lee, Hee Ja; Hwang, In A [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1993-12-01
The report described the operation and the trouble shooting of main computer and KAERINet. The results of the project are as follows; 1. The operation and trouble shooting of the main computer system. (Cyber 170-875, Cyber 960-31, VAX 6320, VAX 11/780). 2. The operation and trouble shooting of the KAERINet. (PC to host connection, host to host connection, file transfer, electronic-mail, X.25, CATV etc.). 3. The development of applications -Electronic Document Approval and Delivery System, Installation the ORACLE Utility Program. 22 tabs., 12 figs. (Author) .new.
Plaziat, J.F.; Moulin, P.; Van Beurden, R.; Ballet, E.
2005-01-01
Building an internal gas market implies establishing harmonized rules for cross border trading between operators. To that effect, the European association EASEE-gas is carrying out standards and procedures, commonly called 'inter-operability'. Set up in 2002, the Association brings together all segments of the gas industry: producers, transporters, distributors, traders and shippers, suppliers, consumers and service providers. This workshop presents the latest status on issues such as barriers to gas trade in Europe, rules and procedures under preparation by EASEE-gas, and the implementation schedule of these rules by operators. This article gathers 5 presentations about this topic given at the gas conference
Bahr, Benjamin; Hellmann, Frank; Kaminski, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy
2011-01-01
The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as our main tool. A set of moves we define in the set of the operator spin foams (among other operations) allows us to split the faces and the edges of the foams. We assign to each operator spin foam a contracted operator, by using the contractions at the vertices and suitably adjusted face amplitudes. The emergence of the face amplitudes is the consequence of assuming the invariance of the contracted operator with respect to the moves. Next, we define spin foam models and consider the class of models assumed to be symmetric with respect to the moves we have introduced, and assuming their partition functions (state sums) are defined by the contracted operators. Briefly speaking, those operator spin foam models are invariant with respect to the cellular decomposition, and are sensitive only to the topology and colouring of the foam. Imposing an extra symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with assumed invariance with respect to the edge splitting move, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on a spin(4) BF spin foam model is exactly the way we tend to view 4D quantum gravity, starting with the BC model and continuing with the Engle-Pereira-Rovelli-Livine (EPRL) or Freidel-Krasnov (FK) models. That makes our framework directly applicable to those models. Specifically, our operator spin foam framework can be translated into the language of spin foams and partition functions. Among our natural spin foam models there are the BF spin foam model, the BC model, and a model corresponding to the EPRL intertwiners. Our operator spin foam framework can also be used for more general spin
2008-09-01
operation were to take Turkey out of the war, open a direct link with the Entente’s embattled ally in Russia, force the Germans to shift troops from the...ing craft, while four combat craft (two tor- pedo craft and two light patrol craft) were captured in Port of Adabia. 5. Hartmut Zehrer, ed., Der...mission as a whole is accomplished. At the operational level, the intent is an expression of the commander’s operational vision. It provides a link
Kawasumi, Takeshi; Funakoshi, Yoshihiro
2008-01-01
KEKB accelerator has been operated since December 1998. We achieved the design peak luminosity of 10.00/nb/s. The present record is 17.12/nb/s. Detailed data of the KEKB Operation is important to evaluate the KEKB performance and to suggest the direction of the performance enhancement. We have classified all KEKB machine time into the following seven categories (1) Physics Run (2) Machine Study (3) Machine Tuning (4) Beam Tuning (5) Trouble (6) Maintenance (7) Others, to estimate the accelerator availability. In this paper we report the operation statistics of the KEKB accelerator. (author)
Operational proof of automation
Jaerschky, R.; Schlicht, K.
1977-01-01
Automation of the power plant process may imply quite a number of problems. The automation of dynamic operations requires complicated programmes often interfering in several branched areas. This reduces clarity for the operating and maintenance staff, whilst increasing the possibilities of errors. The synthesis and the organization of standardized equipment have proved very successful. The possibilities offered by this kind of automation for improving the operation of power plants will only sufficiently and correctly be turned to profit, however, if the application of these equipment techniques is further improved and if it stands in a certain ratio with a definite efficiency. (orig.) [de
1991-08-01
The Nuclear Regulatory Commission's annual summary of licensed nuclear power reactor data is based primarily on the report of operating data submitted by licensees for each unit for the month of December because that report contains data for the month of December, the year to date (in this case calendar 1990) and cumulative data, usually from the date of commercial operation. The data is not independently verified, but various computer checks are made. The report is divided into two sections. The first contains summary highlights and the second contains data on each individual unit in commercial operation. Section 1 capacity and availability factors are simple arithmetic averages. Section 2 items in the cumulative column are generally as reported by the licensee and notes as to the use of weighted averages and starting dates other than commercial operation are provided
Hartfield, R.A.
1994-03-01
The Nuclear Regulatory Commissions annual summary of licensed nuclear power reactor data is based primarily on the report of operating data submitted by licensees for each unit for the month of December, the year to date (in this case calendar year 1993) and cumulative data, usually for the date of commercial operation. The data is not independently verified, but various computer checks are made. The report is divided into two sections. The first contains summary highlights and the second contains data on each individual unit in commercial operation. Section 1 capacity and availability factors are simple arithmetic averages. Section 2 items in the cumulative column are generally as reported by the licensee and notes as to the use of weighted averages and starting dates other than commercial operation are provided
Church, B.W.
1981-01-01
A brief overview is given of weapon test site decontamination activities carried out by Nevada Operations Office. Tabulated data is given of event name, date, location, year of cleanup, and radioisotopes that were present, activity levels, and cost of cleanup
1989-08-01
THE OPERATING UNITS STATUS REPORT - LICENSED OPERATING REACTORS provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management from the Headquarters staff of NRC's Office of Enforcement (OE), from NRC's Regional Offices, and from utilities. The three sections of the report are: monthly highlights and statistics for commercial operating units, and errata from previously reported data; a compilation of detailed information on each unit, provided by NRC's Regional Offices, OE Headquarters and the utilities; and an appendix for miscellaneous information such as spent fuel storage capability, reactor-years of experience and non-power reactors in the US
Department of Homeland Security — This map layer includes crushed stone operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...
Construction Minerals Operations
Department of Homeland Security — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...
Agricultural Minerals Operations
Department of Homeland Security — This map layer includes agricultural minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...
Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...
NONE
1997-10-01
This document is the first edition of Argonne`s new Operating Plan. The Operating Plan complements the strategic planning in the Laboratory`s Institutional Plan by focusing on activities that are being pursued in the immediate fiscal year, FY 1998. It reflects planning that has been done to date, and it will serve in the future as a resource and a benchmark for understanding the Laboratory`s performance. The heart of the Institutional Plan is the set of major research initiatives that the Laboratory is proposing to implement in future years. In contrast, this Operating Plan focuses on Argonne`s ongoing R&D programs, along with cost-saving measures and other improvements being implemented in Laboratory support operations.
Flinchem, J.
1980-01-01
This document contains procedures which apply to operations performed on individual P-1c machines in the Machine Interface Test System (MITS) at AiResearch Manufacturing Company's Torrance, California Facility
Cimesa, S.
2007-01-01
Slovenian Nuclear Safety Administration (SNSA) has developed its own system for tracking, screening and evaluating the operating experiences of the nuclear installations. The SNSA staff regularly tracks the operating experiences throughout the world and screens them on the bases of applicability for the Slovenian nuclear facilities. The operating experiences, which pass the screening, are thoroughly evaluated and also recent operational events in these facilities are taken into account. If needed, more information is gathered to evaluate the conditions of the Slovenian facilities and appropriate corrective actions are considered. The result might be the identification of the need for modification at the licensee, the need for modification of internal procedures in the SNSA or even the proposal for the modification of regulations. Information system helps everybody to track the process of evaluation and proper logging of activities. (author)
Nuclear material operations manual
Tyler, R.P.
1981-02-01
This manual provides a concise and comprehensive documentation of the operating procedures currently practiced at Sandia National Laboratories with regard to the management, control, and accountability of nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion
Administrator
describe military strategy as a sub-component of a broader term, namely national or ... the allocation of the forces and resources required to achieve those objectives could be .... tactical assets, might be considered operational level actions.
Operations Strategy in practice
Rytter, Niels Gorm; Koch, Christian; Boer, Harry
2005-01-01
In this paper, we describe and illustrate a new, action-based longitudinal case study approach, which aims at helping scholars narrow the gap between the theory and practice of Operations Strategy (OS). First, we elaborate on the need for new research methods for studying OS in practice. Then, we...... and disadvantages of the method. Finally, we draw conclusions on its potential for operations strategy and operations management studies.......In this paper, we describe and illustrate a new, action-based longitudinal case study approach, which aims at helping scholars narrow the gap between the theory and practice of Operations Strategy (OS). First, we elaborate on the need for new research methods for studying OS in practice. Then, we...
Operator licensing examiner standards
1983-10-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes. As appropriate, these standards will be revised periodically to accommodate comments and reflect new information or experience
Information Operations: Where Next?
Buchholz, David R
2005-01-01
... to standardized IO training and integration across the combatant commands. For this reason and others there is a compelling argument for the major responsibility for DoD information operations integration to fall under the control of U.S...
U.S. Environmental Protection Agency — This dataset consists of operable unit data from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...
Nuclear material operations manuals
Tyler, R.P.
1979-06-01
This manual is intended to provide a concise and comprehensive documentation of the operating procedures currently practiced at Sandia Laboratories with regard to the management, control, and accountability of radioactive and nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion
Observer's Report - Okinawa Operation
Todd, W. N., Jr
1945-01-01
... for temporary duty in connection with the Okinawa Operation. By verbal agreement between observers, it was decided that each officer would cover certain activities and thus have a complete coverage without duplication...
Payroll Operational Data Store
Social Security Administration — The Payroll ODS will provide a single repository of payroll data to produce accurate and timely financial reports to support operating, budget, and policy decisions.
Operant Conditioning and Education.
de Noronha, Mario
A case study of a learning disabled 8-year-old with behavior disturbancs is presented to highlight the use of operant conditioning in cutting down educational costs and easing the teacher's class management problems. (CL)
Operating experience with snubbers
Levin, H.; Cudlin, R.
1978-06-01
Recent operating experience with hydraulic and mechanical snubbers has indicated that there is a need to evaluate current practice in the industry associated with snubber qualification testing programs, design and analysis procedures, selection and specification criteria, and the preservice inspection and inservice surveillance programs. The report provides a summary of operational experiences that represent problems that are generic throughout the industry. Generic Task A-13 is part of the NRC Program for the Resolution of Generic Issues Related to Nuclear Power Plants described in NUREG-0410. The report is based upon a rather large amount of data that have become available in the past four years. These data have been evaluated by the Division of Operating Reactors to develop a data base for use in connection with several NRC activities including Category A, Technical Activity A-13 (Snubbers); the Standard Review Plan; future Regulatory Guides; ASME Code Provisions; and various technical specifications of operating nuclear power plants
Modelling arithmetic operations
Shabanov-kushnarenk, Yu P
1981-01-01
The possibility of modelling finite alphabetic operators using formal intelligence theory, is explored, with the setting up of models of a 3-digit adder and a multidigit subtractor, as examples. 2 references.
Nuclear material operations manual
Tyler, R.P.; Gassman, L.D.
1978-04-01
This manual is intended to provide a concise and comprehensive documentation of the operating procedures currently practiced at Sandia Laboratories with regard to the management, control, and accountability of radioactive and nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations--management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of ''play-scripts'' in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion
Operations Acceptance Management
Suchá, Ivana
2010-01-01
This paper examines the process of Operations Acceptance Management, whose main task is to control Operations Acceptance Tests (OAT). In the first part the author focuses on the theoretical ground for the problem in the context of ITSM best practices framework ITIL. Benefits, process pitfalls and possibilities for automation are discussed in this part. The second part contains a case study of DHL IT Services (Prague), where a solution optimizing the overall workflow was implemented using simp...
Treasury operations management
Laurențiu Dumitru ANDREI; Petre BREZEANU
2014-01-01
Amid the globalization and centralization of treasury operations, establishing the principles for their optimal management is the instrument by means of which economic stability, market dynamics and standards of living can be ensured. The directions of these principles, as well as their flexibility, depend on correctly identifying the objectives of the financial management planning of treasury operations, in compliance with European and international policies related to this area.
Power reactors operational diagnosis
Dach, K.; Pecinka, L.
1976-01-01
The definition of reactor operational diagnostics is presented and the fundamental trends of research are determined. The possible sources of power reactor malfunctions, the methods of defect detection, the data evaluation and the analysis of the results are discussed in detail. In view of scarcity of a theoretical basis and of insufficient in-core instrumentation, operational diagnostics cannot be as yet incorporated in a computer-aided reactor control system. (author)
Operational Waste Volume Projection
STRODE, J.N.
2000-08-28
Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement. Assumptions were current as of June. 2000.
Operational waste volume projection
Koreski, G.M.; Strode, J.N.
1995-06-01
Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the tri-party agreement. Assumptions are current as of June 1995
JIRKŮ, Radek
2012-01-01
This thesis introduces readers to the MINIX operating system, which was used in the creation of the Linux OS. It discusses the history and development of the system and explains its core and the file system. Also solves MINIX installation and configuration of the virtual machine at each step and deals with disputes that had a creator of Minix creator of Linux. In conclusion, compared with Linux MINIX and summarizes the advantages and disadvantages and the use of the operating system at present.
Operational Waste Volume Projection
STRODE, J.N.
2000-01-01
Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement. Assumptions were current as of June. 2000
Puglisi, M.; Cornacchia, M.
1981-01-01
The need for a very low final amplifier output impedance, always associated with class A operation, requires a very large power waste in the final tube. The recently suggested pulsed rf operation, while saving a large amount of power, increases the inherent final amplifier non linearity. A method is presented for avoiding the large signal non linear analysis and it is shown how each component of the beam induced voltage depends upon all the beam harmonics via some coupling coefficients which are evaluated
Quality in drilling operations
Duncan, E; Gervais, I [Sedco Forex Jacintoport Facility, Channelview, TX (United States); Le Moign, Y; Pangarkar, S; Stibbs, B [Sedco Forex, Montrouge (France); McMorran, P [Sedco Forex, Pau (France); Nordquist, E [Dubai Petroleum Company, Dubai (United Arab Emirates); Pittman, T [Sedco Forex, Perth (Australia); Schindler, H [Sedco Forex, Dubai (United Arab Emirates); Scott, P [Woodside Offshore Petroleum Pty. Ltd., Perth (Australia)
1997-12-31
Driven by cost and profitability pressures, quality has taken on new meaning and importance in the oil field during the past decade. In drilling operations, new initiatives have led to cooperative team efforts between operators and drilling contractors to enhance quality. In this article examples are given of how one drilling contractor, by adopting a quality culture, is reaping major benefits for its clients as well as its employees. 22 figs., 19 refs.
GANIL Team
1992-01-01
The operation of the GANIL accelerator during 1991 and the first half of 1992 is reported. Results obtained with new beams, metallic beams and the first tests with the new injector system using an ECR source installed on a 100 kV platform are also given. Statistics of operation and beam characteristics are presented. The computer control system is also discussed. (K.A.) 7 refs.; 3 figs.; 8 tabs
Quality in drilling operations
Duncan, E.; Gervais, I. [Sedco Forex Jacintoport Facility, Channelview, TX (United States); Le Moign, Y.; Pangarkar, S.; Stibbs, B. [Sedco Forex, Montrouge (France); McMorran, P. [Sedco Forex, Pau (France); Nordquist, E. [Dubai Petroleum Company, Dubai (United Arab Emirates); Pittman, T. [Sedco Forex, Perth (Australia); Schindler, H. [Sedco Forex, Dubai (United Arab Emirates); Scott, P. [Woodside Offshore Petroleum Pty. Ltd., Perth (Australia)
1996-12-31
Driven by cost and profitability pressures, quality has taken on new meaning and importance in the oil field during the past decade. In drilling operations, new initiatives have led to cooperative team efforts between operators and drilling contractors to enhance quality. In this article examples are given of how one drilling contractor, by adopting a quality culture, is reaping major benefits for its clients as well as its employees. 22 figs., 19 refs.
Rudić, Ratko
2016-01-01
This thesis outlines history, development and design of microkernel based operating systems. While the idea of microkernel based architecture emerged early in computer science, there are still very few systems adopting this technology. Microkernel operating systems are divided into several different groups and families that frequently share rules, design decisions and development processes. This master thesis focuses on the main representatives of these groups as well as their mutual...
Operating experience: safety perspective
Piplani, Vivek; Krishnamurthy, P.R.; Kumar, Neeraj; Upadhyay, Devendra
2015-01-01
Operating Experience (OE) provides valuable information for improving NPP safety. This may include events, precursors, deviations, deficiencies, problems, new insights to safety, good practices, lessons and corrective actions. As per INSAG-10, an OE program caters as a fundamental means for enhancing the defence-in-depth at NPPs and hence should be viewed as ‘Continuous Safety Performance Improvement Tool’. The ‘Convention on Nuclear Safety’ also recognizes the OE as a tool of high importance for enhancing the NPP safety and its Article 19 mandates each contracting party to establish an effective OE program at operating NPPs. The lessons drawn from major accidents at Three Mile Island, Chernobyl and Fukushima Daiichi NPPs had prompted nuclear stalwarts to change their safety perspective towards NPPs and to frame sound policies on issues like safety culture, severe accident prevention and mitigation. An effective OE program, besides correcting current/potential problems, help in proactively improving the NPP design, operating and maintenance procedures, practices, training, etc., and thus plays vital role in ensuring safe and efficient operation of NPPs. Further it enhances knowledge with regard to equipment operating characteristics, system performance trends and provides data for quantitative and qualitative safety analysis. Besides all above, an OE program inculcates a learning culture in the organisation and thus helps in continuously enhancing the expertise, technical competency and knowledge base of its staff. Nuclear and Radiation Facilities in India are regulated by Atomic Energy Regulatory Board (AERB). Operating Plants Safety Division (OPSD) of AERB is involved in managing operating experience activities. This paper provides insights about the operating experience program of OPSD, AERB (including its on-line data base namely OPSD STAR) and its utilisation in improving the regulations and safety at Indian NPPs/projects. (author)
Operator licensing examiner standards
1994-06-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes. Revision 7 was published in January 1993 and became effective in August 1993. Supplement 1 is being issued primarily to implement administrative changes to the requalification examination program resulting from the amendment to 10 CFR 55 that eliminated the requirement for every licensed operator to pass an NRC-conducted requalification examination as a condition for license renewal. The supplement does not substantially alter either the initial or requalification examination processes and will become effective 30 days after its publication is noticed in the Federal Register. The corporate notification letters issued after the effective date will provide facility licensees with at least 90 days notice that the examinations will be administered in accordance with the revised procedures
Pipeline system operability review
Eriksson, Kjell [Det Norske Veritas (Norway); Davies, Ray [CC Technologies, Dublin, OH (United States)
2005-07-01
Pipeline operators are continuously working to improve the safety of their systems and operations. In the US both liquid and gas pipeline operators have worked with the regulators over many years to develop more systematic approaches to pipeline integrity management. To successfully manage pipeline integrity, vast amounts of data from different sources needs to be collected, overlaid and analyzed in order to assess the current condition and predict future degradation. The efforts undertaken by the operators has had a significant impact on pipeline safety, nevertheless, during recent years we have seen a number of major high profile accidents. One can therefore ask how effective the pipeline integrity management systems and processes are. This paper will present one methodology 'The Pipeline System Operability Review' that can evaluate and rate the effectiveness of both the management systems and procedures, as well as the technical condition of the hardware. The result from the review can be used to compare the performance of different pipelines within one operating company, as well as benchmark with international best practices. (author)
New operator's console recorder
Anon.
2009-01-01
This article described a software module that automatically records images being shown on multiple HMI or SCADA operator's displays. Videos used for monitoring activities at industrial plants can be combined with the operator console videos and data from a process historian. This enables engineers, analysts or investigators to see what is occurring in the plant, what the operator is seeing on the HMI screen, and all relevant real-time data from an event. In the case of a leak at a pumping station, investigators could watch plant video taken at a remote site showing fuel oil creeping across the floor, real-time data being acquired from pumps, valves and the receiving tank while the leak is occurring. The video shows the operator's HMI screen as well as the alarm screen that signifies the leak detection. The Longwatch Operator's Console Recorder and Video Historian are used together to acquire data about actual plant plant management because they show everything that happens during an event. The Console Recorder automatically retrieves and replays operator displays by clicking on a time-based alarm or system message. Play back of video feed is a valuable tool for training and analysis purposes, and can help mitigate insurance and regulatory issues by eliminating uncertainty and conjecture. 1 fig.
Repository operational criteria analysis
Hageman, J.P.; Chowdhury, A.H.
1992-08-01
The objective of the ''Repository Operational Criteria (ROC) Feasibility Studies'' (or ROC task) was to conduct comprehensive and integrated analyses of repository design, construction, and operations criteria in 10 CFR Part 60 regulations, considering the interfaces and impacts of any potential changes to those regulations. The study addresses regulatory criteria related to the preclosure aspects of the geologic repository. The study task developed regulatory concepts or potential repository operational criteria (PROC) based on analysis of a repository's safety functions and other regulations for similar facilities. These regulatory concepts or PROC were used as a basis to assess the sufficiency and adequacy of the current criteria in 10 CFR Part 60. Where the regulatory concepts were same as current operational criteria, these criteria were referenced. The operations criteria referenced or the PROC developed are given in this report. Detailed analyses used to develop the regulatory concepts and any necessary PROC for those regulations that may require a minor change are also presented. The results of the ROC task showed a need for further analysis and possible major rule change related to the design bases of a geologic repository operations area, siting, and radiological emergency planning
Pipeline system operability review
Eriksson, Kjell [Det Norske Veritas (Norway); Davies, Ray [CC Technologies, Dublin, OH (United States)
2005-07-01
Pipeline operators are continuously working to improve the safety of their systems and operations. In the US both liquid and gas pipeline operators have worked with the regulators over many years to develop more systematic approaches to pipeline integrity management. To successfully manage pipeline integrity, vast amounts of data from different sources needs to be collected, overlaid and analyzed in order to assess the current condition and predict future degradation. The efforts undertaken by the operators has had a significant impact on pipeline safety, nevertheless, during recent years we have seen a number of major high profile accidents. One can therefore ask how effective the pipeline integrity management systems and processes are. This paper will present one methodology 'The Pipeline System Operability Review' that can evaluate and rate the effectiveness of both the management systems and procedures, as well as the technical condition of the hardware. The result from the review can be used to compare the performance of different pipelines within one operating company, as well as benchmark with international best practices. (author)
Varsi, Giulio
In the last decade, the operation of a spacecraft after launch has emerged as a major component of the total cost of the mission. This trend is sustained by the increasing complexity, flexibility, and data gathering capability of the space assets and by their greater reliability and consequent longevity. The trend can, however, be moderated by the progressive transfer of selected functions from the ground to the spacecraft and by application, on the ground, of new technology. Advances in ground operations derive from the introduction in the mission operations environment of advanced microprocessor-based workstations in the class of a few million instructions per second and from the selective application of artificial intelligence technology. In the last few years a number of these applications have been developed, tested in operational settings and successfully demonstrated to users. Some are now being integrated in mission operations facilities. An analysis of mission operations indicates that the key areas are: concurrent control of multiple missions; automated/interactive production of command sequences of high integrity at low cost; automated monitoring of spacecraft health and automated aides for fault diagnosis; automated allocation of resources; automated processing of science data; and high-fidelity, high-speed spacecraft simulation. Examples of major advances in selected areas are described.
Oohashi, Hideaki.
1982-01-01
Purpose: To enable a reactor operator to perform safety and sure inspection for a reactor and take manual start-up operations for the necessary systems at optimum timing with neither misoperation nor misjudging after the occurrence of reactor accidents. Constitution: If a signal judging circuit judges the generation of an accident signal for a reactor, the circuit issues an output signal to start the time counting operation of a time counter thereby inform the elapse of time after the occurrence of the reactor accident. Further, a time signal generated on every predetermined time from the time counter and a process signal indicating the reactor status are logically judged and, if the conditions for taking manual start-up operations, are satisfied, a start-up instruction signal is generated. An information signal is formed depending on the start-up instruction and the content of the start-up instruction is displayed on every predetermined time by the information signal, whereby the operator can perform the manual start-up operations at the optimum timings. (Moriyama, K.)
Reactor operational transient analysis
Shin, W.K.; Chae, S.K.; Han, K.I.; Yang, K.S.; Chung, H. D.; Kim, H.G.; Moon, H.J.; Ryu, Y.H.
1983-01-01
To build up efficient capability of safety review and inspection for the nuclear power plants, four area of studies have performed as follows: 1) In order to search the most optimized operating method during load follow operating schemes, automatic control and normal control, are compared each other under the CAOC condition. The analysis performed by DDID code has shown that the reactor has to be controlled by the operator manually during load follow operation. 2) Through the sensitivity analysis by COBRA code, the operating parameters, such as coolant pressure, flow rate, inlet temperature, and power distribution are shown to be important to the determination of DNBR. Expecially, inlet temperature of primary coolant system is appeared as the most senstive parameter on DNBR. 3) FRAPCON code is adapted to study the sensitivity of several operational parameters on the mechanical properties of reactor fuel rod. 4) The calculations procedure which is required to be obtained the neutron fluence at the reactor vessel and the spectrum at the surveillance capsule is established. The results of computation are conpared with those of FSAR and SWRI report and proved its applicability to reactor surveillance program. (Author)
Bechtel SAIC Company
2002-01-01
Higher and lower temperature operating modes (e.g., above and below the boiling point of water) are alternative approaches to managing the heat produced by the radioactive decay of spent nuclear fuel. Current analyses indicate that a repository at the Yucca Mountain site is likely to comply with applicable safety standards regardless of the particular thermal operating mode. Both modes have potential advantages and disadvantages. With a higher temperature operating mode (HTOM), waste packages (WPs) can be placed closer together. This reduces the number of drifts, the required emplacement area, construction costs, and occupational risks to construction workers. In addition, the HTOM would minimize the amount of water that might contact the waste for hundreds of years after closure. On the other hand, higher temperatures introduce uncertainties in the understanding of the long-term performance of the repository because of uncertainties in the thermal effects on WP lifetime and the near-field environment around the drifts. A lower temperature operating mode (LTOM) has the potential to reduce uncertainties in long-term performance of the repository by limiting the effects of temperature on WP lifetime and on the near-field environment around the drifts. Depending on the combination of operating parameters, a LTOM could require construction of additional drifts, a larger emplacement area, increased construction costs, increased occupational risks to construction works, and a longer period of ventilation than a HTOM. The repository design for the potential Yucca Mountain site is flexible and can be constructed and operated in various operating modes to achieve specific technical objectives, accommodate future policy decisions, and use of new information. For example, the flexible design can be operated across a range of temperatures and can be tailored to achieve specific thermal requirements in the future. To accommodate future policy decisions, the repository can be
Operational Dynamic Configuration Analysis
Lai, Chok Fung; Zelinski, Shannon
2010-01-01
Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified
Wu, L.; Liu, S.; Yang, Yingjie
2016-01-01
Traditional integer order buffer operator is extended to fractional order buffer operator, the corresponding relationship between the weakening buffer operator and the strengthening buffer operator is revealed. Fractional order buffer operator not only can generalize the weakening buffer operator and the strengthening buffer operator, but also realize tiny adjustment of buffer effect. The effectiveness of GM(1,1) with the fractional order buffer operator is validated by six cases.
Upgrade of reactor operation technology
Itoh, Hideaki; Suzuki, Toshiaki; O-kawa, Toshikatsu
2003-01-01
To improve operational reliability and availability, the operation technology for a fast reactor was developed in the ''JOYO''. This report describes the upgrading of the simulator, plant operation management tools and fuel handling system for the MK-III core operation. The simulator was modified to the MK-III version to verify operation manuals, and to train operators in MK-III operation. The plant operation management tool was replaced on the operation experience to increase the reliability and efficiency of plant management works relating to plant operation and maintenance. To shorten the refueling period, the fuel handling system was upgraded to full automatic remote control. (author)
1990-01-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. Since all of the data concerning operation of the units is provided by the utility operators less than two weeks after the end of the month, necessary corrections to published information are shown on the ERRATA page. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Operator representations of frames
Christensen, Ole; Hasannasab, Marzieh
2017-01-01
of the properties of the operator T requires more work. For example it is a delicate issue to obtain a representation with a bounded operator, and the availability of such a representation not only depends on the frame considered as a set, but also on the chosen indexing. Using results from operator theory we show......The purpose of this paper is to consider representations of frames {fk}k∈I in a Hilbert space ℋ of the form {fk}k∈I = {Tkf0}k∈I for a linear operator T; here the index set I is either ℤ or ℒ0. While a representation of this form is available under weak conditions on the frame, the analysis...... that by embedding the Hilbert space ℋ into a larger Hilbert space, we can always represent a frame via iterations of a bounded operator, composed with the orthogonal projection onto ℋ. The paper closes with a discussion of an open problem concerning representations of Gabor frames via iterations of a bounded...
Automated emergency operating procedures
Perez-Ramirez, G.; Nelson, P.F.
1990-01-01
This paper describes the development of a training tool for the symptom oriented emergency operating procedures used at the Laguna Verde Nuclear Power Plant. EOPs and operator training are intended to assist the operator for managing accident situations. A prototype expert system based on the EOPs has been developed for operator training. The demonstration expert system was developed using a commercial shell. The knowledge base consists of two parts. The specific operator actions to be executed for 5 selected accident sequences and the EOPs steps for the reactor pressure vessel control of the water level, pressure, and power. The knowledge is expressed in the form of IF-THEN production rules. A typical training session will display a set of conditions and will prompt the trainee to indicate the appropriate step to perform. This mode will guide the trainee through selected accident sequences. A second mode of the expert system will prompt the trainee for the current plant conditions and the expert system will respond with the EOPs which are required to be performed under these conditions. This allows the trainee to study What if situations
Shimomura, Y.; Huget, M.; Mizoguchi, T.; Murakami, Y.; Polevoi, A.; Shimada, M.; Aymar, R.; Chuyanov, V.; Matsumoto, H.
2001-01-01
ITER is planned to be the first fusion experimental reactor in the world operating for research in physics and engineering. The first 10 years' operation will be devoted primarily to physics issues at low neutron fluence and the following 10 years' operation to engineering testing at higher fluence. ITER can accommodate various plasma configurations and plasma operation modes such as inductive high Q modes, long pulse hybrid modes, non-inductive steady-state modes, with large ranges of plasma current, density, beta and fusion power, and with various heating and current drive methods. This flexibility will provide an advantage for coping with uncertainties in the physics database, in studying burning plasmas, in introducing advanced features and in optimizing the plasma performance for the different programme objectives. Remote sites will be able to participate in the ITER experiment. This concept will provide an advantage not only in operating ITER for 24 hours per day but also in involving the world-wide fusion communities and in promoting scientific competition among the Parties. (author)
1989-06-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. Since all of the data concerning operation of the units are provided by the utility operators less than two weeks after the end of the month, necessary corrections to published information are shown on the ERRATA page. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Chaussade, J.P.
1984-01-01
The correlation between the different accelerated aging methods and operation reality has to be done with solid and representative elements in matter of tests as well as in operating experience. In 1990 in France, the first unit will be 13 years operating, there will be 34 units of 900 MW PWR and 18 units of 1300 MW PWR in operation. The total of experience will be equivalent to 400 reactor-years. Only computerised means permit to collect all corresponding events, to manage them and to draw a lot of conclusions. One describes these computerised applications explaining the different events collected, data input and interrogating possibilities. The first application, called ''events file'', records all important events in nuclear plants. For each of these events, an event reporting format is set up as soon as first informations are known and then is put into the file. An updating is performed when the event is better known and analyzed. Interrogating programs allow no specialist to access easily to this data bank. So it is possible to collect events of the same nature, of the same equipments or of the same systems. The second application called S.R.D.F. (fiability data bank system) collects all maintenance operations on certain mechanical and electrical equipment. These two computerized applications complete on another in the way they allow to do fiability and availability studies for some equipments or for some elements of a nuclear plant [fr
Shimomura, Y.; Huguet, M.; Mizoguchi, T.; Murakami, Y.; Polevoi, A.R.; Shimada, M.; Aymar, R.; Chuyanov, V.A.; Matsumoto, H.
2001-01-01
ITER is planned to be the first fusion experimental reactor in the world operating for research in physics and engineering. The first ten years of operation will be devoted primarily to physics issues at low neutron fluence and the following ten years of operation to engineering testing at higher fluence. ITER can accommodate various plasma configurations and plasma operation modes, such as inductive high Q modes, long pulse hybrid modes and non-inductive steady state modes, with large ranges of plasma current, density, beta and fusion power, and with various heating and current drive methods. This flexibility will provide an advantage for coping with uncertainties in the physics database, in studying burning plasmas, in introducing advanced features and in optimizing the plasma performance for the different programme objectives. Remote sites will be able to participate in the ITER experiment. This concept will provide an advantage not only in operating ITER for 24 hours a day but also in involving the worldwide fusion community and in promoting scientific competition among the ITER Parties. (author)
Altunin, V. I.; Sukhanov, K. G.; Altunin, K. R.
1993-01-01
Radioastron is a space-based very-long-baseline interferometry (VLBI) mission to be operational in the mid-90's. The spacecraft and space radio telescope (SRT) will be designed, manufactured, and launched by the Russians. The United States is constructing a DSN subnet to be used in conjunction with a Russian subnet for Radioastron SRT science data acquisition, phase link, and spacecraft and science payload health monitoring. Command and control will be performed from a Russian tracking facility. In addition to the flight element, the network of ground radio telescopes which will be performing co-observations with the space telescope are essential to the mission. Observatories in 39 locations around the world are expected to participate in the mission. Some aspects of the mission that have helped shaped the flight operations concept are: separate radio channels will be provided for spacecraft operations and for phase link and science data acquisition; 80-90 percent of the spacecraft operational time will be spent in an autonomous mode; and, mission scheduling must take into account not only spacecraft and science payload constraints, but tracking station and ground observatory availability as well. This paper will describe the flight operations system design for translating the Radioastron science program into spacecraft executed events. Planning for in-orbit checkout and contingency response will also be discussed.
1990-01-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Schmidt, T.; Zimoch, D.
2007-01-01
The operation of an APPLE II based undulator beamline with all its polarization states (linear horizontal and vertical, circular and elliptical, and continous variation of the linear vector) requires an effective description allowing an automated calculation of gap and shift parameter as function of energy and operation mode. The extension of the linear polarization range from 0 to 180 deg. requires 4 shiftable magnet arrrays, permitting use of the APU (adjustable phase undulator) concept. Studies for a pure fixed gap APPLE II for the SLS revealed surprising symmetries between circular and linear polarization modes allowing for simplified operation. A semi-analytical model covering all types of APPLE II and its implementation will be presented
Hartfield, R.A.
1990-03-01
The US Nuclear Regulatory Commission's monthly Licensed Operating Reactors Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Yuzhakov, A.Yu.
2010-01-01
The author reports on the application of full-scale simulators for training and maintaining proficiency of unit control room operators that is an essential element of Russian NPPs personnel education system. The existing simulators for the unit control room operating personnel are listed. The integrated approach to developing and maintaining the training hardware is described. The integrated approach is being implemented on the basis of observance of the existing requirements to training hardware, improvement of regulations, control from a single centre responsible for the provision of support to the activities, inclusion into the plans of simulators for development of skills for operating control over equipment and systems, as well as control from local boards [ru
Banach, S
1987-01-01
This classic work by the late Stefan Banach has been translated into English so as to reach a yet wider audience. It contains the basics of the algebra of operators, concentrating on the study of linear operators, which corresponds to that of the linear forms a1x1 + a2x2 + ... + anxn of algebra.The book gathers results concerning linear operators defined in general spaces of a certain kind, principally in Banach spaces, examples of which are: the space of continuous functions, that of the pth-power-summable functions, Hilbert space, etc. The general theorems are interpreted in various mathematical areas, such as group theory, differential equations, integral equations, equations with infinitely many unknowns, functions of a real variable, summation methods and orthogonal series.A new fifty-page section (``Some Aspects of the Present Theory of Banach Spaces'''') complements this important monograph.
Operations management for construction
March, Chris
2009-01-01
Students studying construction management and related subjects need to have a broad understanding of the major aspects of controlling the building processes. Operations Management for Construction is one of three textbooks (Business Organisation, Operations Management and Finance Control) written to systematically cover the field. Focusing on construction sites and operations which are challenging to run, Chris March explores issues such as the setting up of the site, the deciding of the methodology of construction, and the sequence of work and resourcing. As changing and increasing regulations affect the way sites are managed, he also considers the issues and methods of successful administering, safety, quality and environment. Finally, the contractor's responsibility to the environment, including relationships with third parties, selection of materials, waste management and sustainability is discussed. Chris March has a wealth of practical experience in the construction industry, as well as considerable exp...
ORNL radioactive waste operations
Sease, J.D.; King, E.M.; Coobs, J.H.; Row, T.H.
1982-01-01
Since its beginning in 1943, ORNL has generated large amounts of solid, liquid, and gaseous radioactive waste material as a by-product of the basic research and development work carried out at the laboratory. The waste system at ORNL has been continually modified and updated to keep pace with the changing release requirements for radioactive wastes. Major upgrading projects are currently in progress. The operating record of ORNL waste operation has been excellent over many years. Recent surveillance of radioactivity in the Oak Ridge environs indicates that atmospheric concentrations of radioactivity were not significantly different from other areas in East Tennesseee. Concentrations of radioactivity in the Clinch River and in fish collected from the river were less than 4% of the permissible concentration and intake guides for individuals in the offsite environment. While some radioactivity was released to the environment from plant operations, the concentrations in all of the media sampled were well below established standards
1989-08-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
1997-01-01
In 1996, Nuclear Regulatory Authority of the Slovak Republic (NRA SR) ensured the Slovak Republic (SR) obligations with relation to the international agreements and with the SR membership in the IAEA.International co-operation has been ensured on the basis of the bilateral international agreements. With the Ministry of Foreign Affairs co-operation, the SR fulfilled its financial obligations to this organization in due time and in the full scope. Representing Central and Eastern Europe interest in the Board of Governors, the SR participation in the highest executive in the highest executive authority was finished in 1996.The Board of Governors Vice-chairman position was executed by NRA SR Chairman. 5 national and 6 regional technical co-operation and assistance projects were realized in 1996. 12 organizations participated in these projects and accordingly 104 experts took part in training programmes, scientific visits or as the mission members abroad. Besides, Slovak experts participated at work of technical advisory and consultation groups with the significant assistance. In the framework of IAEA co-operation, the SR was visited by 11 expert missions formed by 28 experts from 19 countries including IAEA. Slovak organizations, namely institutes of the Academy of Sciences, Slovak research centres and universities participated in IAEA scientific and research activities through NRA SR. 15 scientific contracts in total were approved and realized and these contracts are utilized as supplementary financing of the own scientific and research projects. Other international co-operation and regional co-operation activities of the NRA SR in 1996 are reviewed
Schardt, John
2007-01-01
GNF's latest generation fuel product, GNF2, is designed to deliver improved nuclear efficiency, higher bundle and cycle energy capability, and more operational flexibility. But along with high performance, our customers face a growing need for absolute fuel reliability. This is driven by a general sense in the industry that LWR fuel reliability has plateaued. Too many plants are operating with fuel leakers, and the impact on plant operations and operator focus is unacceptable. The industry has responded by implementing an INPO-coordinated program aimed at achieving leaker-free reliability by 2010. One focus area of the program is the relationship between fuel performance (i.e., duty) and reliability. The industry recognizes that the right balance between performance and problem-free fuel reliability is critical. In the development of GNF2, GNF understood the requirement for a balanced solution and utilized a product development and introduction strategy that specifically addressed reliability: evolutionary design features supported by an extensive experience base; thoroughly tested components; and defense-in-depth mitigation of all identified failure mechanisms. The final proof test that the balance has been achieved is the application of the design, initially through lead use assemblies (LUAs), in a variety of plants that reflect the diversity of the BWR fleet. Regular detailed surveillance of these bundles provides the verification that the proper balance between performance and reliability has been achieved. GNF currently has GNF2 lead use assemblies operating in five plants. Included are plants that have implemented extended power up-rates, plants on one and two-year operating cycles, and plants with and without NobleChem TM and zinc injection. The leading plant has undergone three pool-side inspections outages to date. This paper reviews the actions taken to insure GNF2's reliability, and the lead use assembly surveillance data accumulated to date to validate
SSCL Commissioning and Operations
1992-01-01
The SSC, with an energy of 20 TeV/Beam, requires a sequence of individual accelerators of increasing energy in the injector chain. These are the Linac, Low Energy Booster, Medium Energy Booster, and High Energy Booster. Each accelerator system must be completed in sequence in order to provide beam to the next higher energy accelerator. The collider itself is comprised of ten sectors, each of which in terms of superconducting magnet bending strength, is equivalent to two HEB injectors. The completion of all injectors and collider sectors is required before stored beams can circulate in preparation for colliding beam operation. Four experimental halls are planned for the detector systems. Each major detector will be assembled in one of the halls by a world-wide collaboration of scientists. In addition, above ground facilities provide shops and test facilities for accelerator technical systems, superconducting magnet and materials research and development, and for detector assembly and operations. The purpose of this report is to present a plan for the sequential commissioning and operation of these individual accelerators and other technical facilities of the SSC. A central objective of this plan is to describe the activities at the SSCL that are not included as part of the construction project TPC, even though they occur during the overall project construction time-frame. Examples of such activities include the operation of general laboratory facilities and services not specifically related to construction, the operating costs for the individual accelerators in the injector chain once these facilities have been commissioned, and the costs of SSCL physics research groups. The Department of Energy has provided the following decision with regard to these operations categories for the SSCL
The operation and maintenance manual
Klein, W.; Krotil, H.; Stoll, A.
1975-01-01
The Operating Manual is one of many technical documents which the nuclear power plant operator needs for ensuring safe operation. For the operating staff, however, there is only one document, namely the Operating Manual. It contains, appropriately arranged, the necessary system and other diagrams, drawings, lists, licensing documents and similar material, which are necessary for understanding the design, for testing, for obtaining the operating licence and for the operation of individual systems and of the entire plant. (orig./RW) [de
Piping engineering and operation
1993-01-01
The conference 'Piping Engineering and Operation' was organized by the Institution of Mechanical Engineers in November/December 1993 to follow on from similar successful events of 1985 and 1989, which were attended by representatives from all sectors of the piping industry. Development of engineering and operation of piping systems in all aspects, including non-metallic materials, are highlighted. The range of issues covered represents a balance between current practices and implementation of future international standards. Twenty papers are printed. Two, which are concerned with pressurized pipes or steam lines in the nuclear industry, are indexed separately. (Author)
TRIGA reactor operating experience
Anderson, T.V.
1970-01-01
The Oregon State TRIGA Reactor (OSTR) has been in operation 3 years. Last August it was upgraded from 250 kW to 1000 kW. This was accomplished with little difficulty. During the 3 years of operation no major problems have been experienced. Most of the problems have been minor in nature and easily corrected. They came from lazy susan (dry bearing), Westronics Recorder (dead spots in the range), The Reg Rod Magnet Lead-in Circuit (a new type lead-in wire that does not require the lead-in cord to coil during rod withdrawal hss been delivered, much better than the original) and other small corrections
Ball, Joseph A; Helton, JWilliam; Rodman, Leiba; Spitkovsky, Iiya
2010-01-01
This is the first volume of a collection of original and review articles on recent advances and new directions in a multifaceted and interconnected area of mathematics and its applications. It encompasses many topics in theoretical developments in operator theory and its diverse applications in applied mathematics, physics, engineering, and other disciplines. The purpose is to bring in one volume many important original results of cutting edge research as well as authoritative review of recent achievements, challenges, and future directions in the area of operator theory and its applications.
Operational Design for Peace Enforcement: Lessons for the Operational Staff
Neumann, Michael
2004-01-01
U.S. involvement in Somalia serves as a useful case study of the unique challenges an operational staff may face when applying operational design to the planning and execution of a peace enforcement operation. U.S...
Systemic Operational Design: Enhancing the Joint Operation Planning Process
Delacruz, Victor J
2007-01-01
Operational level commanders and their staffs require relevant and current joint doctrine that articulates the critical function of operational design and its role in the Joint Operation Planning Process (JOPP...
Seminar 1. Joint Military Operations. Application of the Operational Reserve
Copp, A
1997-01-01
.... As a means of achieving decisive effect at the operational level of war, the operational reserve should be considered an operational function and should be addressed as both a planning element...
The operation and maintenance manual
Stoll, A.; Krotil, H.; Klein, W.
1976-01-01
The operating manual is one of many technical documents which the nuclear power plant operator needs for ensuring safe operation. For the operating staff, however, there is only one document, namely the operating manual. The operating manual is an essential element in bringing man and machine in harmony. This is necessary for safe and, as far as possible, uninterrupted operation of the power plant. The operating manual is the only document containing binding instructions for plant operation. All the tasks of plant operation which are carried out by plant staff are described in the operating manual in a form which is as clear and comprehensible as possible. A considerable number of these tasks can only be carried out by man, namely: 1) tasks concerning operational organization, 2) all non-automated areas of plant operation. (orig./TK) [de
Cyber Operations Virtual Environment
2010-09-01
capability independent of the operator’s willingness to make target responses (See, Macmillan & Creelman , 1991; Parasuraman, Masalonis, & Hancock, 2000...Ma, K-L. (2004). Visualization for security. Computer Graphics, 38, 4-6. Macmillan, N. A., & Creelman , C. D. (1991). Detection theory: A user’s
Rocco, David A.
1994-01-01
Redefining the approach and philosophy that operations management uses to define, develop, and implement space missions will be a central element in achieving high efficiency mission operations for the future. The goal of a cost effective space operations program cannot be realized if the attitudes and methodologies we currently employ to plan, develop, and manage space missions do not change. A management philosophy that is in synch with the environment in terms of budget, technology, and science objectives must be developed. Changing our basic perception of mission operations will require a shift in the way we view the mission. This requires a transition from current practices of viewing the mission as a unique end product, to a 'mission development concept' built on the visualization of the end-to-end mission. To achieve this change we must define realistic mission success criteria and develop pragmatic approaches to achieve our goals. Custom mission development for all but the largest and most unique programs is not practical in the current budget environment, and we simply do not have the resources to implement all of our planned science programs. We need to shift our management focus to allow us the opportunity make use of methodologies and approaches which are based on common building blocks that can be utilized in the space, ground, and mission unique segments of all missions.
Operator/contractor relationships
Smith, J.R.; Kidwell, C.K.; Unger, V.E.; Fercho, E.; Helmer, C.M.
1992-01-01
In May 1988, Shell Western E and P Inc. (SWEPI) and partners Elf Aquitaine Petroleum and Conoco Inc. signed a letter of intent with Canadian Marine Drilling Ltd. (Canmar) for provision of exploratory drilling and marine services on leases in OCS Lease Sale 109 in the Chukchi Sea, Alaska. The 5450 blocks offered in the remote sale area west of Point Barrow ranged from 3 to 240 miles (5 to 380 km) offshore in water depths from 26 to 263 feet (8 to 80 m). The principal interest tracts were at least 75 miles (120 km) offshore and north of 70 degrees N latitude. The remoteness and total lack of any oilfield infrastructure required considerable planning and coordination between Operator and Contractor in order to carry out the three-year drilling program efficiently and safely in an environmentally harsh and, at the same time, sensitive area. SWEPI and Canmar developed a close working relationship from the start of the project through a number of participative approaches to the problems that had to be solved. This paper reports that these included strong reliance on operational planning meetings, post-season analyses, and an overall emphasis on the teamwork required of both parties to carry out the first-ever drilling program in the Chukchi Sea. This approach led to a very successful operation for both parties and emphasizes the positive benefits achievable when Operator and Contractor work as a team
Operations research and development
The paper begins with a discussion of the concepts “operations research” .... have in common an emphasis on the “scientific” and quantitative aspects of .... It is important to ensure that the MCDA methodologies are sufficiently simple and .... 2006, is an excellent example of the application of OR techniques to a topic with.
Silver, E.G.
1988-01-01
This update, which appears regularly in each issue of Nuclear Safety, surveys the operations of those power reactors in the US which have been issued operating licenses. Table 1 shows the number of such reactors and their net capacities as of September 30, 1987, the end of the three-month period covered in this report. Table 2 lists the unit capacity and forced outage rate for each licensed reactor for each of the three months (July, August, and September 1987) covered in this report and the cumulative values of these parameters since the beginning of commercial operation. In addition to the tabular data, this article discusses other significant occurrences and developments that affected licensed US power reactors during this reporting period. Status changes at Braidwood Unit 1, Nine Mile Point 2, and Beaver Valley 2 are discussed. Other occurrences discussed are: retraining of control-room operators at Peach Bottom; a request for 25% power for Shoreham, problems at Fermi 2 which delayed the request to go to 75% power; the results of a safety study of the N Reactor at Hanford; a proposed merger of Pacific Gas and Electric with Sacramento Municipal Utility District which would result in the decommissioning of Rancho Seco; the ordered shutdown of Oyster Creek; a minor radioactivity release caused by a steam generator tube rupture at North Anna 1; and 13 fines levied by the NRC on reactor licensees
Meulmeester, P.; De Laat, J.
2006-01-01
The Netherlands Competition Authority (NMa), in which the Office of Energy Regulation (DTe) is included plan to decrease the capital cost compensation (or weighted average cost of capital or WACC) for grid operators. In this article it is explained how the compensation is calculated, why this measure will be taken and what the effects of this cutback are [nl
EN Department
2010-01-01
To facilitate snow clearing operations, which commence at 4.30 in the morning, all drivers of CERN cars are kindly requested to park them together in groups. This will help us greatly assist us in our work. Thank-you for your help. Transport Group / EN-HE Tel. 72202
Splunk operational intelligence cookbook
Diakun, Josh; Mock, Derek
2014-01-01
This book is intended for users of all levels who are looking to leverage the Splunk Enterprise platform as a valuable operational intelligence tool. The recipes provided in this book will appeal to individuals from all facets of a business - IT, Security, Product, Marketing, and many more!
Slepniov, Dmitrij; Wæhrens, Brian Vejrum; Gubi, Ebbe
2013-01-01
Companies are actively seeking competitive advantage through their choice of location and ownership of operations. The purpose of this chapter is to uncover hidden effects of this development and propose how companies can respond to them. The chapter draws on a case study of a Danish industrial e...... of analysis and involving temporal adaptations. In terms of managerial implications, the study provides managers with lessons for designing a robust system of globally dispersed operations.......Companies are actively seeking competitive advantage through their choice of location and ownership of operations. The purpose of this chapter is to uncover hidden effects of this development and propose how companies can respond to them. The chapter draws on a case study of a Danish industrial...... equipment firm and describes how its operations configuration has been changing over time. The chapter identifies the key determinants of this change and uncovers some of its hidden effects. The chapter closes with propositions for how to respond to these effects through the development of a distinct...
Resilient Grid Operational Strategies
Pasqualini, Donatella [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-03-01
Extreme weather-related disturbances, such as hurricanes, are a leading cause of grid outages historically. Although physical asset hardening is perhaps the most common way to mitigate the impacts of severe weather, operational strategies may be deployed to limit the extent of societal and economic losses associated with weather-related physical damage.1 The purpose of this study is to examine bulk power-system operational strategies that can be deployed to mitigate the impact of severe weather disruptions caused by hurricanes, thereby increasing grid resilience to maintain continuity of critical infrastructure during extreme weather. To estimate the impacts of resilient grid operational strategies, Los Alamos National Laboratory (LANL) developed a framework for hurricane probabilistic risk analysis (PRA). The probabilistic nature of this framework allows us to estimate the probability distribution of likely impacts, as opposed to the worst-case impacts. The project scope does not include strategies that are not operations related, such as transmission system hardening (e.g., undergrounding, transmission tower reinforcement and substation flood protection) and solutions in the distribution network.
[Lateral epicondylitis: conservative - operative].
Altintas, Burak; Greiner, Stefan
2016-10-01
Lateral epicondylitis is a common disease of the common extensor origin at the lateral humerus. Despite its common self-limitation it can lead to chronic therapy-resistant pain with remarkable functional disability of the affected arm. Different conservative and operative treatment options of lateral epicondylitis are described and compared regarding benefits and risks. Additionally, recent surgical techniques and their complications are mentioned. Based on the current literature, it is shown which treatment option can be recommended. This review was based on the literature analysis in PubMed regarding "conservative and operative therapy of lateral epicondylitis" as well as the clinical experience of the authors. Conservative treatment is the primary choice for the treatment of lateral epicondylitis if concomitant pathologies such as instability among others can be excluded. It should include strengthening against resistance with eccentric stretching of the extensor group. In persistent cases, operative treatment is warranted. Resection of the pathologic tissue at the extensor origin with debridement and refixation of the healthy tendinous tissue yields good results. Most patients with lateral epicondylitis can be treated conservatively with success. Radiological evaluation should be performed in therapy-resistant cases. In the case of partial or complete rupture of the extensor origin, operative therapy is indicated.
McKim, Vicky L
2017-06-01
In the world of risk management, which encompasses the business continuity disciplines, many types of risk require evaluation. Financial risk is most often the primary focus, followed by product and market risks. Another critical area, which typically lacks a thorough review or may be overlooked, is operational risk. This category encompasses many risk exposure types including those around building structures and systems, environmental issues, nature, neighbours, clients, regulatory compliance, network, data security and so on. At times, insurance carriers will assess internal hazards, but seldom do these assessments include more than a cursory look at other types of operational risk. In heavily regulated environments, risk assessments are required but may not always include thorough assessments of operational exposures. Vulnerabilities may linger or go unnoticed, only to become the catalyst for a business disruption at a later time, some of which are so severe that business recovery becomes nearly impossible. Businesses may suffer loss of clients as the result of a prolonged disruption of services. Comprehensive operational risk assessments can assist in identifying such vulnerabilities, exposures and threats so that the risk can be minimised or removed. This paper lays out how an assessment of this type can be successfully conducted.
Mullender, Sape J.
1987-01-01
In the past five years, distributed operating systems research has gone through a consolidation phase. On a large number of design issues there is now considerable consensus between different research groups. In this paper, an overview of recent research in distributed systems is given. In turn, the
Space Operations Learning Center
Lui, Ben; Milner, Barbara; Binebrink, Dan; Kuok, Heng
2012-01-01
The Space Operations Learning Center (SOLC) is a tool that provides an online learning environment where students can learn science, technology, engineering, and mathematics (STEM) through a series of training modules. SOLC is also an effective media for NASA to showcase its contributions to the general public. SOLC is a Web-based environment with a learning platform for students to understand STEM through interactive modules in various engineering topics. SOLC is unique in its approach to develop learning materials to teach schoolaged students the basic concepts of space operations. SOLC utilizes the latest Web and software technologies to present this educational content in a fun and engaging way for all grade levels. SOLC uses animations, streaming video, cartoon characters, audio narration, interactive games and more to deliver educational concepts. The Web portal organizes all of these training modules in an easily accessible way for visitors worldwide. SOLC provides multiple training modules on various topics. At the time of this reporting, seven modules have been developed: Space Communication, Flight Dynamics, Information Processing, Mission Operations, Kids Zone 1, Kids Zone 2, and Save The Forest. For the first four modules, each contains three components: Flight Training, Flight License, and Fly It! Kids Zone 1 and 2 include a number of educational videos and games designed specifically for grades K-6. Save The Forest is a space operations mission with four simulations and activities to complete, optimized for new touch screen technology. The Kids Zone 1 module has recently been ported to Facebook to attract wider audience.
South African Airborne Operations
South Africa carried out numerous airborne operations during the latter part .... It was a lesson the French had learned and were learning in Indo-China and ..... South African government, concerned that the conflict would spill across their northern border, ...... the Super Frelon and it was an outstanding helicopter at sea level.
Averaging operations on matrices
2014-07-03
Jul 3, 2014 ... Role of Positive Definite Matrices. • Diffusion Tensor Imaging: 3 × 3 pd matrices model water flow at each voxel of brain scan. • Elasticity: 6 × 6 pd matrices model stress tensors. • Machine Learning: n × n pd matrices occur as kernel matrices. Tanvi Jain. Averaging operations on matrices ...
Almost periodic Schroedinger operators
Bellissard, J.; Lima, R.
1984-01-01
These lectures are devoted to recent developments in the theory of almost-periodic Schroedinger Operators. We specially describe the algebraic point of view, with applications to gap-labelling theorems. Particular models are also presented which exhibit various spectral properties. (orig.)
Electromagnetically Operated Counter
Goldberg, H D; Goldberg, M I
1951-12-18
An electromagnetically operated counter wherein signals to be counted are applied to cause stepwise rotation of a rotatable element which is connected to a suitable register. The mechanism involved consists of a rotatable armature having three spaced cores of magnetic material and a pair of diametrically opposed electromagnets with a suitable pulsing circuit to actuate the magnets.
Dam safety operating guidelines
Elsayed, E.; Leung, T.; Kirkham, A.; Lum, D.
1990-01-01
As part of Ontario Hydro's dam structure assessment program, the hydraulic design review of several river systems has revealed that many existing dam sites, under current operating procedures, would not have sufficient discharge capacity to pass the Inflow Design Flood (IDF) without compromising the integrity of the associated structures. Typical mitigative measures usually considered in dealing with these dam sites include structural alterations, emergency action plans and/or special operating procedures designed for extreme floods. A pilot study was carried out for the Madawaska River system in eastern Ontario, which has seven Ontario Hydro dam sites in series, to develop and evaluate the effectiveness of the Dam Safety Operating Guidelines (DSOG). The DSOG consist of two components: the flood routing schedules and the minimum discharge schedules, the former of which would apply in the case of severe spring flood conditions when the maximum observed snowpack water content and the forecast rainfall depth exceed threshold values. The flood routing schedules would identify to the operator the optimal timing and/or extent of utilizing the discharge facilities at each dam site to minimize the potential for dam failures cased by overtopping anywhere in the system. It was found that the DSOG reduced the number of structures overtopped during probable maximum flood from thirteen to four, while the number of structures that could fail would be reduced from seven to two. 8 refs., 4 figs., 3 tabs
Operations and Modeling Analysis
Ebeling, Charles
2005-01-01
The Reliability and Maintainability Analysis Tool (RMAT) provides NASA the capability to estimate reliability and maintainability (R&M) parameters and operational support requirements for proposed space vehicles based upon relationships established from both aircraft and Shuttle R&M data. RMAT has matured both in its underlying database and in its level of sophistication in extrapolating this historical data to satisfy proposed mission requirements, maintenance concepts and policies, and type of vehicle (i.e. ranging from aircraft like to shuttle like). However, a companion analyses tool, the Logistics Cost Model (LCM) has not reached the same level of maturity as RMAT due, in large part, to nonexistent or outdated cost estimating relationships and underlying cost databases, and it's almost exclusive dependence on Shuttle operations and logistics cost input parameters. As a result, the full capability of the RMAT/LCM suite of analysis tools to take a conceptual vehicle and derive its operations and support requirements along with the resulting operating and support costs has not been realized.
2010-03-26
important events receive the most attention. Ensures that absentees and flank units receive changes to the operation order. Transmits changes to them...York: Vintage Books, 1991. Fuller, J. F. C. Generalship: Its Diseases and Their Cure . Harrisburg, PA: Military Service Publishing Co., 1936
Manually operated coded switch
Barnette, J.H.
1978-01-01
The disclosure related to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made
Mueck, Robert P.; Parker, Ashley
2011-01-01
Sometimes one never knows what sparks an idea or causes people to come together and take something forward. An example of this is Operation COP at the University of Maryland in College Park. Their version of the "See Something, Say Something" campaign is being touted as a crime prevention program, while it is at the same time an…
Invariant differential operators
Dobrev, Vladimir K
2016-01-01
With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory.
Teachers and Operant Conditioning.
Frey, Sherman
A survey was conducted of 406 elementary, middle, and secondary school teachers to determine their understanding, acceptance, and use of the principle of operant conditioning. The treatment of data was by percent and chi square analysis primarily according to sex, experience, degree, and position. Subjects reported that a) they believed that the…
Operant Conditioning - Token Economy.
Montgomery, Jacqueline; McBurney, Raymond D.
Described is an Operant Conditioning-Token Economy Program, teaching patients to be responsible for their own behavior, to make choices, and to be motivated to change. The program was instigated with mentally ill patients in a state hospital and was later used with institutionalized mentally handicapped groups. After two years, only four of the…
Invariant differential operators
Dobrev, Vladimir K
With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory.
Operational Area Environmental Evaluations
Bailey-White, Brenda Eileen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nagy, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wagner, Katrina Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Goodman, Thomas Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herring, Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Catechis, Christopher S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kinghorn, Aubrianna Nicole [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Ellie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Barthel, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casaus, Benito [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-08-01
The Operational Area Environmental Evaluation update provides a description of activities that have the potential to adversely affect natural and cultural resources, including soil, air, water, biological, ecological, and historical resources. The environmental sensitivity of an area is evaluated and summarized, which may facilitate informed management decisions as to where development may be prohibited, restricted, or subject to additional requirements.
1998-01-01
A brief account of activities in international co-operation carried out by the Nuclear power plants Jaslovske Bohunice in 1997 is presented. Professionality of the Bohunice NPPs staff was highly appreciated by inviting them to be the OSART team members
1979-01-01
The qualifications required and the training received by FFTF operators are described. The training includes sodium fill training and cold plant qualification. Requirements for supervisors are also outlined. Arrangement of personnel at FFTF is described. Requalification training and recertification are considered
G.W.J. Hendrikse (George); C.P. Veerman (Cees)
2000-01-01
textabstractMarketing co-operatives (MCs) are analysed from an incomplete contracting perspective. The requirement of the domination of control by the members of a MC is a threat to the survival of a MC in markets where the level of asset specificity at the processing stage of production is
Monitoring of operating processes
Barry, R.F.
1981-01-01
Apparatus is described for monitoring the processes of a nuclear reactor to detect off-normal operation of any process and for testing the monitoring apparatus. The processes are evaluated by response to their paramters, such as temperature, pressure, etc. The apparatus includes a pair of monitoring paths or signal processing units. Each unit includes facilities for receiving on a time-sharing basis, a status binary word made up of digits each indicating the status of a process, whether normal or off-normal, and test-signal binary words simulating the status binary words. The status words and test words are processed in succession during successive cycles. During each cycle, the two units receive the same status word and the same test word. The test words simulate the status words both when they indicate normal operation and when they indicate off-normal operation. Each signal-processing unit includes a pair of memories. Each memory receives a status word or a test word, as the case may be, and converts the received word into a converted status word or a converted test word. The memories of each monitoring unit operate into a non-coincidence which signals non-coincidence of the converted word out of one memory of a signal-processing unit not identical to the converted word of the other memory of the same unit
Kjellsdotter, Linea; Dukovska-Popovska, Iskra; Kaipia, Riikka
2015-01-01
This paper investigates sales and operations planning (S&OP) at four Scandinavian industrial food producers in order to explore how the use of S&OP might help leaders to deal with the challenges set by the planning environment. Variables connected to the product and market, e.g., frequency of new...
Kjellsdotter, Linea; Dukovska-Popovska, Iskra; Kaipia, Riikka
2013-01-01
This paper explores how the use of sales and operations planning (S&OP) may deal with the challenges set by the planning environment by investigating S&OP at four Scandinavian industrial food producers. Variables connected to the product and market, e.g. perishability, customer service elements...
Operational Amplifer Integrator
van Tuijl, Adrianus Johannes Maria
2003-01-01
An integrator circuit comprises an operational amplifier which has a transistor stage (1) with an input terminal (4) and an output terminal (3), a feedback capacitor (2) connected between the input terminal (4) and the output terminal (3), and a resistor (5) connected to the input terminal (4), and
On commuting operator exponentials, II
where N is an unbounded normal operator and M is a bounded normal operator in the. Hilbert space. Keywords. Self-adjoint and normal operator; commuting normal operator exponent- ials; Borel functional calculus. 1. Introduction. Let E be a complex Hilbert space and let B(E) be the algebra of bounded linear operators.
Effectiveness of operation tools developed by KEKB operators
Sugino, K.; Satoh, Y.; Kitabayashi, T.
2004-01-01
The main tasks of KEKB (High Energy Accelerator Research Organization B-physics) operators are beam tuning and injection, operation logging, monitoring of accelerator conditions and safety management. New beam tuning methods are frequently applied to KEKB in order to accomplish high luminosity. In such a situation, various operation tools have been developed by the operators to realize efficient operation. In this paper, we describe effectiveness of tools developed by the operators. (author)
Nos, V.; Faig, J.; Plesa, P.; Delgado, J. L.
2000-01-01
The systematic approach to training is internationally accepted as the best method to achieve and maintain the qualification and competence of power plant personnel and to guarantee the quality of their training. Following the recommendations and guidelines of international organisations competent in the field, TECNATOM SA has developed projects based on the systematic approach to training for all Spanish nuclear power plants. One of the latest projects was the systematic approach to training developed for the operation personnel of ASCO Nuclear Power Plant. In this case, certain results of the Probabilistic Safety Analysis (PSA) which complement the systematic safety and reliability criteria of the systematic approach to training process have been incorporated in the traditional processes of work and task analysis and training plan design. This incorporation provides the training manager with additional criteria based not only on safety aspects obtained through the statistical treatment of considerations of skilled technical personnel (operators, operation chief supervisors, etc), but also on the independent criterion of the PSA. The inclusion of this approach basically affects all systematics in two of its stages: During the selection process of operating practices in SMR or SGI, the possible scenarios have been associated with all those situations where human actions which lead to an initiating event or human actions to mitigate an initiating event, may take place, as defined in the PSA. During the scenario development process, the instruments involved in the performance of human actions which originate or mitigate an event taking place have been identified. This pakes it possible to reconcile the scenario event sequence with the sequence considered in the PSA study, as the most likely to provoke a more serious accident. The incorporation of these PSA results contributes to the strengthening of safety aspects in training in an objective way, and confirms that
Cohering power of quantum operations
Bu, Kaifeng, E-mail: bkf@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China); Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Zhang, Lin, E-mail: linyz@zju.edu.cn [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Junde, E-mail: wjd@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China)
2017-05-18
Highlights: • Quantum coherence. • Cohering power: production of quantum coherence by quantum operations. • Study of cohering power and generalized cohering power, and their comparison for differentmeasures of quantum coherence. • Operational interpretation of cohering power. • Bound on cohering power of a generic quantum operation. - Abstract: Quantum coherence and entanglement, which play a crucial role in quantum information processing tasks, are usually fragile under decoherence. Therefore, the production of quantum coherence by quantum operations is important to preserve quantum correlations including entanglement. In this paper, we study cohering power–the ability of quantum operations to produce coherence. First, we provide an operational interpretation of cohering power. Then, we decompose a generic quantum operation into three basic operations, namely, unitary, appending and dismissal operations, and show that the cohering power of any quantum operation is upper bounded by the corresponding unitary operation. Furthermore, we compare cohering power and generalized cohering power of quantum operations for different measures of coherence.
Density operators in quantum mechanics
Burzynski, A.
1979-01-01
A brief discussion and resume of density operator formalism in the way it occurs in modern physics (in quantum optics, quantum statistical physics, quantum theory of radiation) is presented. Particularly we emphasize the projection operator method, application of spectral theorems and superoperators formalism in operator Hilbert spaces (Hilbert-Schmidt type). The paper includes an appendix on direct sums and direct products of spaces and operators, and problems of reducibility for operator class by using the projection operators. (author)
Regulations for RA reactor operation
1980-09-01
Regulations for RA reactor operation are written in accordance with the legal regulations defined by the Law about radiation protection and related legal acts, as well as technical standards according to the IAEA recommendations. The contents of this book include: fundamental data about the reactor; legal regulations for reactor operation; organizational scheme for reactor operation; general and detailed instructions for operation, behaviour in the reactor building, performing experiments; operating rules for operation under steady state and accidental conditions [sr
Weakly compact operators and interpolation
Maligranda, Lech
1992-01-01
The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. In this survey, we have collected and ordered some of this (partly very new) knowledge. We have also included some comments, remarks and examples. The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. I...
Efficient boiler operations sourcebook
Payne, F.W. (comp.)
1985-01-01
This book emphasizes the practical aspects of industrial and commercial boiler operations. It starts with a comprehensive review of general combustion and boiler fundamentals and then deals with specific efficiency improvement methods, and the cost savings which result. The book has the following chapter headings: boiler combustion fundamentals; boiler efficiency goals; major factors controlling boiler efficiency; boiler efficiency calculations; heat loss; graphical solutions; preparation for boiler testing; boiler test procedures; efficiency-related boiler maintenance procedures; boiler tune-up; boiler operational modifications; effect of water side and gas side scale deposits; load management; auxillary equipment to increase boiler efficiency; air preheaters and economizers; other types of auxillary equipment; combustion control systems and instrumentation; boiler O/sub 2/ trim controls; should you purchase a new boiler.; financial evaluation procedures; case studies. The last chapter includes a case study of a boiler burning pulverized coal and a case study of stoker-fired coal.
1973-01-01
The NOAA Fleet Operations Report 1973 was developed to provide a summary of project accomplishments during calendar year 1973. The report was prepared from season, cruise and special reports submitted by ships of the fleet. Centralized management of the NOAA Fleet was finalized by changing the operational control of the National Marine Fisheries Service (NMFS) Ships DAVID STARR JORDAN (FRS 44), TOWNSEND CROMWELL (FRS 43) and MURRE II (FRV 63) from NMFS to the National Ocean Survey on July 1, 1973. Throughout the year, ships routinely collected and transmitted weather data. Similarly, as NOAA participants in the Integrated Global Ocean Station System (IGOSS) service program, XBT observations were taken and either radioed or submitted in log form via mail. In addition, particulate and radionuclide samples were taken in cooperation with the Atomic Energy Commission, sediment samples were obtained for the Smithsonian Institution and observations were made of marine mammals
ATLAS IBL operational experience
AUTHOR|(INSPIRE)INSPIRE-00237659; The ATLAS collaboration
2017-01-01
The Insertable B-Layer (IBL) is the inner most pixel layer in the ATLAS experiment, which was installed at 3.3 cm radius from the beam axis in 2014 to improve the tracking performance. To cope with the high radiation and hit occupancy due to proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed for the IBL. After the long shut-down period over 2013 and 2014, the ATLAS experiment started data-taking in May 2015 for Run-2 of the Large Hadron Collider (LHC). The IBL has been operated successfully since the beginning of Run-2 and shows excellent performance with the low dead module fraction, high data-taking efficiency and improved tracking capability. The experience and challenges in the operation of the IBL is described as well as its performance.
Tevatron lower temperature operation
Theilacker, J.C.
1994-07-01
This year saw the completion of three accelerator improvement projects (AIP) and two capital equipment projects pertaining to the Tevatron cryogenic system. The projects result in the ability to operate the Tevatron at lower temperature, and thus higher energy. Each project improves a subsystem by expanding capabilities (refrigerator controls), ensuring reliability (valve box, subatmospheric hardware, and compressor D), or enhancing performance (cold compressors and coldbox II). In January of 1994, the Tevatron operated at an energy of 975 GeV for the first time. This was the culmination, of many years of R ampersand D, power testing in a sector (one sixth) of the Tevatron, and final system installation during the summer of 1993. Although this is a modest increase in energy, the discovery potential for the Top quark is considerably improved
Train operation in emergencies
Jia, Limin; Qin, Yong
2017-01-01
This book presents the latest findings on train operation theories and methods in the context of emergencies. It examines and assesses a range of aspects—including the definition of a railway emergency, transport organization modes in emergencies, calculating railway transport capacity in emergencies, line planning in emergencies, train re-pathing in emergencies and train re-scheduling in emergencies—that are urgently needed in the railway transportation field, which faces the serious challenge of dealing with emergencies worldwide. The book highlights the latest research results in an integrated and systematic way, and the methodology presented is oriented on real-world problems, allowing it to be used not only directly in railway operational management, but also as the point of departure for further applications or theoretical research. As such, the book will be of considerable interest to graduate students and researchers in the field of traffic and transportation engineering.>.
Nasr, T. N.; Golbeck, H.; Korpany, G.; Pierce, G. [Alberta Research Council, Edmonton, AB (Canada)
1998-12-31
Steam-assisted gravity drainage (SAGD) has become one of the most effective means of recovering oil from oil sands deposits that are too deeply buried for surface mining. In general terms, the process involves drilling paired horizontal wells, one well above the other, and separated by a distance, near the bottom of the oil-bearing formation. The top well is used to inject the steam, heating up the oil and allowing it to drain under the action of gravity, into the bottom well. This paper reviews advances in SAGD operating strategies, based on work at the Underground Test Facility (UTF) in Alberta. Problems that continue to challenge researchers and operators, and concepts to overcome these challenges are discussed in terms of laboratory studies at UTF, designed to improve SAGD oil-to-steam ratios and to reduce water requirements for the process. 8 refs., 20 figs.
Financing Canadian international operations
Beagle, G.
1996-01-01
A primer on financing international operations by Canadian corporations was provided. Factors affecting the availability to project finance (location, political risk), the various forms of financing (debt, equity, and combinations), the main sources of government backed financing to corporations (the International Finance Corporation) (IFC), the European Bank for Reconstruction and Development (EBRD), the Asian Development Bank (ADB), the Overseas Property Insurance Corporation (OPIC), government or agency guarantees, political risk coverage, the use of offshore financial centres, and the where, when and how these various organizations operate, were reviewed. Examples of all of the above, taken from the experiences of Canadian Occidental Petroleum of Calgary in the U.S., in South America, in the Middle and Far East, and in Kazakhstan, were used as illustrations. figs
Economical motor transport operations
Cooke, P
1979-09-01
Motor transport is one area in a company where energy conservation is a function primarily of operative education and motivation rather than mechanical or technical control and monitoring. Unless the driver wants to save energy by proper operation of the vehicle, there is nothing the company can do to force him, whatever equipment it fits to the vehicles, or incentives it offers. This article gives an overview of the use of energy in road transport and examines a number of actions that can be taken to conserve energy. It discusses the question of the cost-effectiveness of transport energy conservation in the light of the complex issues involved. The problems and opportunities of implementing energy-saving programs are examined. (MCW)
Operational and environmental safety
Anon.
1978-01-01
The responsibility of the DOE Office of Operational and Environmental Safety is to assure that DOE-controlled activities are conducted in a manner that will minimize risks to the public and employees and will provide protection for property and the environment. The program supports the various energy technologies by identifying and resolving safety problems; developing and issuing safety policies, standards, and criteria; assuring compliance with DOE, Federal, and state safety regulations; and establishing procedures for reporting and investigating accidents in DOE operations. Guidelines for the radiation protection of personnel; radiation monitoring at nuclear facilities; an assessment of criticality accidents by fault tree analysis; and the preparation of environmental, safety, and health standards applicable to geothermal energy development are discussed
Hurricane slams gulf operations
Anon.
1992-01-01
This paper reports that reports of damage by Hurricane Andrew escalated last week as operators stepped up inspections of oil and gas installations in the Gulf of Mexico. By midweek, companies operating in the gulf and South Louisiana were beginning to agree that earlier assessments of damage only scratched the surface. Damage reports included scores of lost, toppled, or crippled platforms, pipeline ruptures, and oil slicks. By midweek the U.S. coast Guard had received reports of 79 oil spills. Even platforms capable of resuming production in some instances were begin curtailed because of damaged pipelines. Offshore service companies the another 2-4 weeks could be needed to fully assess Andrew's wrath. Lack of personnel and equipment was slowing damage assessment and repair
2014-05-01
There are two principal directions that disaster studies pursue: (1) interventional; and (2) noninterventional. Interventional studies are used to evaluate specific responses as to their effectiveness in meeting their respective objectives, their contribution to the overarching goal, the efficiency with which they are able to achieve their objectives, other effects created, and their respective costs. On the other hand, noninterventional studies examine the epidemiology of disasters and for the most part are observational. Both interventional and noninterventional studies require data/information obtained from assessments. This section of these Guidelines examines the operational framework used to study interventions/responses and includes the following processes: (1) assessments, (2) identification of needs; (3) strategic planning; (4) selection of intervention(s); (5) operational planning; (6) execution of interventions; and (7) monitoring and evaluation of effects and changes in levels of functions resulting from the intervention(s) being studied.
1993-01-01
C Language Integrated Production System (CLIPS), a NASA-developed expert systems program, is used by American Airlines for three purposes: as a rapid prototyping tool; to develop production prototypes; and to develop production application. An example of the latter is CLIPS' use in "Hub S1AAshing," a knowledge based system that recommends contingency plans when severe schedule reductions must be made. Hub S1AAshing has replaced a manual, labor intensive process. It saves time and allows Operations Control Coordinators to handle more difficult situations. Because the system assimilates much of the information necessary to facilitate educated decision making, it minimizes negative impact in situations where it is impossible to operate all flights.
Buhl, Kenneth Øhlenschlæger
2012-01-01
Formålet med denne artikel er at se nærmere på erfaringerne fra den maritime kampagne under den militære indsats i konflikten i Libyen i 2011, som i NATO regi blev kendt som Operation Unified Protector (OUP). Dækningen i de danske medier fokuserede primært på luftkampagnen, hvilket må tilskrives,...
Preparation to exceptional operations
Sort, M.
1984-01-01
Preparation to special maintenance operations requires a specific approach according to the considered intervention type. Replacement of vapor generators is representative of a kind of intervention where technics is generally only an adaptation to the power plant context of processes already in application in construction, and where methodology, planning and organization have an important role because of the variety and the quantity of taskworks to be done, the involved manpower, the dosimetry and time lag requirements [fr
1990-01-01
In less than fifty years, a sophisticated technical language has developed worldwide around broad-ranging operations in the field of nuclear technology. In South Africa the need to adapt this new technical language in an orderly and acceptable manner for common use was identified. The aim of this dictionary is to promote the use of correct nuclear technology in both English and Afrikaans, and to aid in the translation of nuclear terms from English into Afrikaans
1990-01-01
In less than fifty years, a sophisticated technical language has developed worldwide around broad-ranging operations in the field of nuclear technology. In South Africa the need to adapt this new technical language in an orderly and acceptable manner for common use was identified. The aim of this dictionary is to promote the use of correct nuclear terminology in both Afrikaans and English, and to aid in the translation of nuclear terms from Afrikaans into English
Frederickson, J.R.; Horgos, R.M.
1983-10-01
An automated nuclear fuel fabrication line is being designed for installation in the Fuels and Materials Examination Facility (FMEF) near Richland, Washington. The fabrication line will consist of seven major process systems: Receiving and Powder Preparation; Powder Conditioning; Pressing and Boat Loading; Debinding, Sintering, and Property Adjustment; Boat Transport; Pellet Inspection and Finishing; and Pin Operations. Fuel powder processing through pellet pressing will be discussed in this paper
Pressurised water reactor operation
Birnie, S.; Lamonby, J.K.
1987-01-01
The operation of a pressurized water reactor (PWR) is described with respect to the procedure for a unit start-up. The systems details and numerical data are for a four loop PWR station of the design proposed for Sizewell-'B', United Kingdom. A description is given of: the initial conditions, filling the reactor coolant system (RCS), heat-up and pressurisation of the RCS, secondary system preparations, reactor start-up, and reactivity control at power. (UK)
Operational electricity transmission rates
Roggen, M.
1997-01-01
In a liberalized electricity market both the consumers and the producers of electricity must pay for the use of the power transmission network. Thus, the net manager has unlimited options to realize efficiency improvements. A neutral and transparent management of the power grid is necessary to avoid disturbance of the market. KEMA Consulting translated abstract ideas and strategic advices to operational concepts in its report 'A framework for the determination of tariffs of the transport in the Dutch electricity sector'
Operational Shock Complexity Theory
2005-05-26
Theory : Recommendations For The National Strategy To Defeat Terrorism.” Student Issue Paper, Center for Strategic Leadership , US Army War College, July...Lens of Complexity Theory : Recommendations For The National Strategy To Defeat Terrorism.” (Student Issue Paper, Center for Strategic Leadership , US...planners managed to cause confusion in the enemy’s internal model by operating in an unexpected manner. 140 Glenn E. James, “Chaos Theory : The
Rotorwash Operational Footprint Modeling
2014-07-01
I-13. Francis, J. K., and Gillespie, A., “Relating Gust Speed to Tree Damage in Hurricane Hugo , 1989,” Journal of Arboriculture, November 1993...statement has been Rotorwash Operational Footprint Modeling 72 found to be correct. In many parts of the United States, the requirements for hurricane ...On August 18, 1983, Hurricane Alicia struck downtown Houston, Texas. Researchers were allowed into downtown Houston the following day to help survey
Niklas Blomberg; Martin Cook; Pablo Roman Garcia; Stephanie Suhr; Premysl Velek; Montserrat Gonzalez; Susanna Repo
2017-01-01
ELIXIR is a distributed infrastructure, built around existing centres of excellence throughout the European member states represented through national Nodes, and incorporating the internationally supported European Bioinformatics Institute (EMBL-EBI). There are currently over 160 institutes from 20 member states taking part in ELIXIR. Operating a large, distributed, ‘virtual’ organisation such as ELIXIR requires strong coordination capabilities with clear roles and effective and simple proces...
Magnetically operated check valve
Morris, Brian G.; Bozeman, Richard J., Jr.
1994-06-01
A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.
Education Payload Operation - Demonstrations
Keil, Matthew
2009-01-01
Education Payload Operation - Demonstrations (EPO-Demos) are recorded video education demonstrations performed on the International Space Station (ISS) by crewmembers using hardware already onboard the ISS. EPO-Demos are videotaped, edited, and used to enhance existing NASA education resources and programs for educators and students in grades K-12. EPO-Demos are designed to support the NASA mission to inspire the next generation of explorers.
1993-01-01
It is reported that energy policy was designed following the European Bank for Reconstruction and Development review of the most pressing energy issues confronting Central and Eastern Europe and the republics of the former Soviet Union. The main features of the policy described in the document set the general framework for the Bank's energy operations. Energy strategies for particular countries are designed as an integral part of the Bank's individual country strategies. Tabs
Baston, Helen
2004-05-01
This is the third 'midwifery basics' series aimed at student midwives, and focuses on midwifery care during labour. This article provides a summary of peri-operative care for women who experience caesarean birth. Students are encouraged to seek further information through a series of activities, and to link theory with practice by considering the issues relating to the care of the woman described in the short vignette.
Operator ordering and causality
Plimak, L. I.; Stenholm, S. T.
2011-01-01
It is shown that causality violations [M. de Haan, Physica 132A, 375, 397 (1985)], emerging when the conventional definition of the time-normal operator ordering [P.L.Kelley and W.H.Kleiner, Phys.Rev. 136, A316 (1964)] is taken outside the rotating wave approximation, disappear when the amended definition [L.P. and S.S., Annals of Physics, 323, 1989 (2008)] of this ordering is used.
Oscillators and operational amplifiers
Lindberg, Erik
2005-01-01
A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation of the general circuit is derived. The dynamic nonlinear transfer characteristic of the amplifier is investigated. Examples of negative resistance oscillators are discussed.
Newland, D.J.; Krupar, J.J.
1984-01-01
In April 1982, the FFTF began its first nominally 100 day irradiation cycle. Since that time the plant has operated very well with steadily increasing plant capacity factors during its first four cycles. One hundred fifty fuel assemblies (eighty of which are experiments) and over 32,000 individual fuel pins have been irradiated, some in excess of 100 MWd/Kg burnup. Specialized equipment and systems unique to sodium cooled reactor plants have performed well
Gaussian operations and privacy
Navascues, Miguel; Acin, Antonio
2005-01-01
We consider the possibilities offered by Gaussian states and operations for two honest parties, Alice and Bob, to obtain privacy against a third eavesdropping party, Eve. We first extend the security analysis of the protocol proposed in [Navascues et al. Phys. Rev. Lett. 94, 010502 (2005)]. Then, we prove that a generalized version of this protocol does not allow one to distill a secret key out of bound entangled Gaussian states
2007-01-01
operation were to take Turkey out of the war, open a direct link with the Entente’s embattled ally Russia, force the Ger- mans to shift troops from the...heavy losses. By August 1915, the allied forces amounted to twelve divisions. A new landing was conducted in early August at Suvla Bay aimed to link ...lethal weapons, such as antiship missiles and tor- pedoes , and the nature of the physical environment. Here again, combat be- tween modern naval forces
2015 Special Operations Essays
2015-05-01
this emerging technology, but how to operate within it as well. Figure 1. Egypt population pyramid . Source: United States Census Bureau...vital during events in Egypt in 2011. In comparing the 100 days it took to overthrow the Shah in the 1979 Iranian Revolution to the 18 days in which the...Figure 1, which is expected to continue to be seen in Egypt over the next several decades.12 The popularity of social media within this demographic was
Targets of operation monitoring
Wenger, H.
1997-01-01
The condition monitoring system of a nuclear power plant should be an assurance for the user and the authorities that the safety of the installation constantly corresponds to the nominal condition. As soon as deviations from these conditions occur, it should quickly provide fundamentals for corrective measures. It contributes to a high degree of availability of the installation and makes safe and economical operation throughout the whole life of the installation possible. (author) 1 fig
Osumi, Katsumi; Miki, Minoru.
1979-01-01
Purpose: To prevent stress corrosion cracks by decreasing the dissolved oxygen and hydrogen peroxide concentrations in the coolants within a reactor container upon transient operation such as at the start-up or shutdown of bwr type reactors. Method: After a condensate has been evacuated, deaeration operation is conducted while opening a main steam drain line, as well as a main steam separation valve and a by-pass valve in a turbine by-pass line connecting the main steam line and the condenser without by way of a turbine, and the reactor is started-up by the extraction of control rods after the concentration of dissolved oxygen in the cooling water within a pressure vessel has been decreased below a predetermined value. Nuclear heating is started after the reactor water has been increased to about 150 0 C by pump heating after the end of the deaeration operation for preventing the concentration of hydrogen peroxide and oxygen in the reactor water from temporarily increasing immediately after the start-up. The corrosive atmosphere in the reactor vessel can thus be moderated. (Horiuchi, T.)
Operating experience in reprocessing
Schueller, W.
1983-01-01
Since 1953, reprocessing has accumulated 180 years of operating experience in ten plants, six of them with 41 years of operation in reprocessing oxide fuel from light water reactors. After abortive, premature attempts at what is called commercial reprocessing, which had been oriented towards the market value of recoverable uranium and plutonium, non-military reprocessing technologies have proved their technical feasibility, since 1966 on a pilot scale and since 1976 on an industrial scale. Reprocessing experience obtained on uranium metal fuel with low and medium burnups can now certainly be extrapolated to oxide fuel with high burnup and from pilot plants to industrial scale plants using the same technologies. The perspectives of waste management of the nuclear power plants operated in the Federal Republic of Germany should be viewed realistically. The technical problems still to be solved are in a balanced relationship to the benefit arising to the national economy out of nuclear power generation and can be solved in time, provided there are clearcut political boundary conditions. (orig.) [de
Barklow, T.; Brau, J.; Fujii, K.; Gao, J.; List, J.; Walker, N.; Yokoya, K.; Collaboration: ILC Parameters Joint Working Group
2015-06-15
The ILC Technical Design Report documents the design for the construction of a linear collider which can be operated at energies up to 500 GeV. This report summarizes the outcome of a study of possible running scenarios, including a realistic estimate of the real time accumulation of integrated luminosity based on ramp-up and upgrade processes. The evolution of the physics outcomes is emphasized, including running initially at 500 GeV, then at 350 GeV and 250 GeV. The running scenarios have been chosen to optimize the Higgs precision measurements and top physics while searching for evidence for signals beyond the standard model, including dark matter. In addition to the certain precision physics on the Higgs and top that is the main focus of this study, there are scientific motivations that indicate the possibility for discoveries of new particles in the upcoming operations of the LHC or the early operation of the ILC. Follow-up studies of such discoveries could alter the plan for the centre-of-mass collision energy of the ILC and expand the scientific impact of the ILC physics program. It is envisioned that a decision on a possible energy upgrade would be taken near the end of the twenty year period considered in this report.
Veretenov, V.Yu.; Volkov, A.I.; Gurevich, M.I.; Kozik, V.S.; Pod'yachev, E.I.; Shapiro, M.L.
1974-01-01
A disc operational system is proposed, which is based on the file structure and designed for use in a BESM-6 computer with the software system comprising a dispatcher DD-73 and a monitor 'Dubna'. The main distinguishing feature of the disc operational system is the decentralization of the file system. Each disc package is an independent file unaffected by the state of the other disc packages. The use of several disc packages is allowed. The above feature of the disc operational system makes it possible to simplify the language of communication with the system, to give the user the opportunity of controlling the file quite independently, and to simplify the maintenance of the discs by the computer personnel. One and the same disc can be simultaneously addressed by all problems in the processor (both mathematical and service). A single file, however, may be used in the recording mode by only one problem. The description presented is the instruction for users. It also describes special possibilities open to the system programmers [ru