Local Random Quantum Circuits are Approximate Polynomial-Designs

NASA Astrophysics Data System (ADS)

Brandão, Fernando G. S. L.; Harrow, Aram W.; Horodecki, Michał

2016-09-01

We prove that local random quantum circuits acting on n qubits composed of O( t 10 n 2) many nearest neighbor two-qubit gates form an approximate unitary t-design. Previously it was unknown whether random quantum circuits were a t-design for any t > 3. The proof is based on an interplay of techniques from quantum many-body theory, representation theory, and the theory of Markov chains. In particular we employ a result of Nachtergaele for lower bounding the spectral gap of frustration-free quantum local Hamiltonians; a quasi-orthogonality property of permutation matrices; a result of Oliveira which extends to the unitary group the path-coupling method for bounding the mixing time of random walks; and a result of Bourgain and Gamburd showing that dense subgroups of the special unitary group, composed of elements with algebraic entries, are ∞-copy tensor-product expanders. We also consider pseudo-randomness properties of local random quantum circuits of small depth and prove that circuits of depth O( t 10 n) constitute a quantum t-copy tensor-product expander. The proof also rests on techniques from quantum many-body theory, in particular on the detectability lemma of Aharonov, Arad, Landau, and Vazirani. We give applications of the results to cryptography, equilibration of closed quantum dynamics, and the generation of topological order. In particular we show the following pseudo-randomness property of generic quantum circuits: Almost every circuit U of size O( n k ) on n qubits cannot be distinguished from a Haar uniform unitary by circuits of size O( n ( k-9)/11) that are given oracle access to U.

Quantum coherence generating power, maximally abelian subalgebras, and Grassmannian geometry

NASA Astrophysics Data System (ADS)

Zanardi, Paolo; Campos Venuti, Lorenzo

2018-01-01

We establish a direct connection between the power of a unitary map in d-dimensions (d < ∞) to generate quantum coherence and the geometry of the set Md of maximally abelian subalgebras (of the quantum system full operator algebra). This set can be seen as a topologically non-trivial subset of the Grassmannian over linear operators. The natural distance over the Grassmannian induces a metric structure on Md, which quantifies the lack of commutativity between the pairs of subalgebras. Given a maximally abelian subalgebra, one can define, on physical grounds, an associated measure of quantum coherence. We show that the average quantum coherence generated by a unitary map acting on a uniform ensemble of quantum states in the algebra (the so-called coherence generating power of the map) is proportional to the distance between a pair of maximally abelian subalgebras in Md connected by the unitary transformation itself. By embedding the Grassmannian into a projective space, one can pull-back the standard Fubini-Study metric on Md and define in this way novel geometrical measures of quantum coherence generating power. We also briefly discuss the associated differential metric structures.

Attitudes and cognitive distances: On the non-unitary and flexible nature of cognitive maps.

PubMed

Carbon, Claus-Christian; Hesslinger, Vera M

2013-01-01

Spatial relations of our environment are represented in cognitive maps. These cognitive maps are prone to various distortions (e.g., alignment and hierarchical effects) caused by basic cognitive factors (such as perceptual and conceptual reorganization) but also by affectively loaded and attitudinal influences. Here we show that even differences in attitude towards a single person representing a foreign country (here Barack Obama and the USA) can be related to drastic differences in the cognitive representation of distances concerning that country. Europeans who had a positive attitude towards Obama's first presidential program estimated distances between US and European cities as being much smaller than did people who were skeptical or negative towards Obama's ideas. On the basis of this result and existing literature, arguments on the non-unitary and flexible nature of cognitive maps are discussed.

Randomly displaced phase distribution design and its advantage in page-data recording of Fourier transform holograms.

PubMed

Emoto, Akira; Fukuda, Takashi

2013-02-20

For Fourier transform holography, an effective random phase distribution with randomly displaced phase segments is proposed for obtaining a smooth finite optical intensity distribution in the Fourier transform plane. Since unitary phase segments are randomly distributed in-plane, the blanks give various spatial frequency components to an image, and thus smooth the spectrum. Moreover, by randomly changing the phase segment size, spike generation from the unitary phase segment size in the spectrum can be reduced significantly. As a result, a smooth spectrum including sidebands can be formed at a relatively narrow extent. The proposed phase distribution sustains the primary functions of a random phase mask for holographic-data recording and reconstruction. Therefore, this distribution is expected to find applications in high-density holographic memory systems, replacing conventional random phase mask patterns.

Attitudes and cognitive distances: On the non-unitary and flexible nature of cognitive maps

PubMed Central

Carbon, Claus-Christian; Hesslinger, Vera M.

2013-01-01

Spatial relations of our environment are represented in cognitive maps. These cognitive maps are prone to various distortions (e.g., alignment and hierarchical effects) caused by basic cognitive factors (such as perceptual and conceptual reorganization) but also by affectively loaded and attitudinal influences. Here we show that even differences in attitude towards a single person representing a foreign country (here Barack Obama and the USA) can be related to drastic differences in the cognitive representation of distances concerning that country. Europeans who had a positive attitude towards Obama’s first presidential program estimated distances between US and European cities as being much smaller than did people who were skeptical or negative towards Obama’s ideas. On the basis of this result and existing literature, arguments on the non-unitary and flexible nature of cognitive maps are discussed. PMID:24155860

Efficient Quantum Pseudorandomness.

PubMed

Brandão, Fernando G S L; Harrow, Aram W; Horodecki, Michał

2016-04-29

Randomness is both a useful way to model natural systems and a useful tool for engineered systems, e.g., in computation, communication, and control. Fully random transformations require exponential time for either classical or quantum systems, but in many cases pseudorandom operations can emulate certain properties of truly random ones. Indeed, in the classical realm there is by now a well-developed theory regarding such pseudorandom operations. However, the construction of such objects turns out to be much harder in the quantum case. Here, we show that random quantum unitary time evolutions ("circuits") are a powerful source of quantum pseudorandomness. This gives for the first time a polynomial-time construction of quantum unitary designs, which can replace fully random operations in most applications, and shows that generic quantum dynamics cannot be distinguished from truly random processes. We discuss applications of our result to quantum information science, cryptography, and understanding the self-equilibration of closed quantum dynamics.

Rényi Entropies from Random Quenches in Atomic Hubbard and Spin Models.

PubMed

Elben, A; Vermersch, B; Dalmonte, M; Cirac, J I; Zoller, P

2018-02-02

We present a scheme for measuring Rényi entropies in generic atomic Hubbard and spin models using single copies of a quantum state and for partitions in arbitrary spatial dimensions. Our approach is based on the generation of random unitaries from random quenches, implemented using engineered time-dependent disorder potentials, and standard projective measurements, as realized by quantum gas microscopes. By analyzing the properties of the generated unitaries and the role of statistical errors, with respect to the size of the partition, we show that the protocol can be realized in existing quantum simulators and used to measure, for instance, area law scaling of entanglement in two-dimensional spin models or the entanglement growth in many-body localized systems.

Rényi Entropies from Random Quenches in Atomic Hubbard and Spin Models

NASA Astrophysics Data System (ADS)

Elben, A.; Vermersch, B.; Dalmonte, M.; Cirac, J. I.; Zoller, P.

2018-02-01

We present a scheme for measuring Rényi entropies in generic atomic Hubbard and spin models using single copies of a quantum state and for partitions in arbitrary spatial dimensions. Our approach is based on the generation of random unitaries from random quenches, implemented using engineered time-dependent disorder potentials, and standard projective measurements, as realized by quantum gas microscopes. By analyzing the properties of the generated unitaries and the role of statistical errors, with respect to the size of the partition, we show that the protocol can be realized in existing quantum simulators and used to measure, for instance, area law scaling of entanglement in two-dimensional spin models or the entanglement growth in many-body localized systems.

Computation of transform domain covariance matrices

NASA Technical Reports Server (NTRS)

Fino, B. J.; Algazi, V. R.

1975-01-01

It is often of interest in applications to compute the covariance matrix of a random process transformed by a fast unitary transform. Here, the recursive definition of fast unitary transforms is used to derive recursive relations for the covariance matrices of the transformed process. These relations lead to fast methods of computation of covariance matrices and to substantial reductions of the number of arithmetic operations required.

Improved mapping of the travelling salesman problem for quantum annealing

NASA Astrophysics Data System (ADS)

Troyer, Matthias; Heim, Bettina; Brown, Ethan; Wecker, David

2015-03-01

We consider the quantum adiabatic algorithm as applied to the travelling salesman problem (TSP). We introduce a novel mapping of TSP to an Ising spin glass Hamiltonian and compare it to previous known mappings. Through direct perturbative analysis, unitary evolution, and simulated quantum annealing, we show this new mapping to be significantly superior. We discuss how this advantage can translate to actual physical implementations of TSP on quantum annealers.

Robust Learning Control Design for Quantum Unitary Transformations.

PubMed

Wu, Chengzhi; Qi, Bo; Chen, Chunlin; Dong, Daoyi

2017-12-01

Robust control design for quantum unitary transformations has been recognized as a fundamental and challenging task in the development of quantum information processing due to unavoidable decoherence or operational errors in the experimental implementation of quantum operations. In this paper, we extend the systematic methodology of sampling-based learning control (SLC) approach with a gradient flow algorithm for the design of robust quantum unitary transformations. The SLC approach first uses a "training" process to find an optimal control strategy robust against certain ranges of uncertainties. Then a number of randomly selected samples are tested and the performance is evaluated according to their average fidelity. The approach is applied to three typical examples of robust quantum transformation problems including robust quantum transformations in a three-level quantum system, in a superconducting quantum circuit, and in a spin chain system. Numerical results demonstrate the effectiveness of the SLC approach and show its potential applications in various implementation of quantum unitary transformations.

Multiqubit Clifford groups are unitary 3-designs

NASA Astrophysics Data System (ADS)

Zhu, Huangjun

2017-12-01

Unitary t -designs are a ubiquitous tool in many research areas, including randomized benchmarking, quantum process tomography, and scrambling. Despite the intensive efforts of many researchers, little is known about unitary t -designs with t ≥3 in the literature. We show that the multiqubit Clifford group in any even prime-power dimension is not only a unitary 2-design, but also a 3-design. Moreover, it is a minimal 3-design except for dimension 4. As an immediate consequence, any orbit of pure states of the multiqubit Clifford group forms a complex projective 3-design; in particular, the set of stabilizer states forms a 3-design. In addition, our study is helpful in studying higher moments of the Clifford group, which are useful in many research areas ranging from quantum information science to signal processing. Furthermore, we reveal a surprising connection between unitary 3-designs and the physics of discrete phase spaces and thereby offer a simple explanation of why no discrete Wigner function is covariant with respect to the multiqubit Clifford group, which is of intrinsic interest in studying quantum computation.

Scalable randomized benchmarking of non-Clifford gates

NASA Astrophysics Data System (ADS)

Cross, Andrew; Magesan, Easwar; Bishop, Lev; Smolin, John; Gambetta, Jay

Randomized benchmarking is a widely used experimental technique to characterize the average error of quantum operations. Benchmarking procedures that scale to enable characterization of n-qubit circuits rely on efficient procedures for manipulating those circuits and, as such, have been limited to subgroups of the Clifford group. However, universal quantum computers require additional, non-Clifford gates to approximate arbitrary unitary transformations. We define a scalable randomized benchmarking procedure over n-qubit unitary matrices that correspond to protected non-Clifford gates for a class of stabilizer codes. We present efficient methods for representing and composing group elements, sampling them uniformly, and synthesizing corresponding poly (n) -sized circuits. The procedure provides experimental access to two independent parameters that together characterize the average gate fidelity of a group element. We acknowledge support from ARO under Contract W911NF-14-1-0124.

Generalized Entanglement Entropies of Quantum Designs.

PubMed

Liu, Zi-Wen; Lloyd, Seth; Zhu, Elton Yechao; Zhu, Huangjun

2018-03-30

The entanglement properties of random quantum states or dynamics are important to the study of a broad spectrum of disciplines of physics, ranging from quantum information to high energy and many-body physics. This Letter investigates the interplay between the degrees of entanglement and randomness in pure states and unitary channels. We reveal strong connections between designs (distributions of states or unitaries that match certain moments of the uniform Haar measure) and generalized entropies (entropic functions that depend on certain powers of the density operator), by showing that Rényi entanglement entropies averaged over designs of the same order are almost maximal. This strengthens the celebrated Page's theorem. Moreover, we find that designs of an order that is logarithmic in the dimension maximize all Rényi entanglement entropies and so are completely random in terms of the entanglement spectrum. Our results relate the behaviors of Rényi entanglement entropies to the complexity of scrambling and quantum chaos in terms of the degree of randomness, and suggest a generalization of the fast scrambling conjecture.

Generalized Entanglement Entropies of Quantum Designs

NASA Astrophysics Data System (ADS)

Liu, Zi-Wen; Lloyd, Seth; Zhu, Elton Yechao; Zhu, Huangjun

2018-03-01

The entanglement properties of random quantum states or dynamics are important to the study of a broad spectrum of disciplines of physics, ranging from quantum information to high energy and many-body physics. This Letter investigates the interplay between the degrees of entanglement and randomness in pure states and unitary channels. We reveal strong connections between designs (distributions of states or unitaries that match certain moments of the uniform Haar measure) and generalized entropies (entropic functions that depend on certain powers of the density operator), by showing that Rényi entanglement entropies averaged over designs of the same order are almost maximal. This strengthens the celebrated Page's theorem. Moreover, we find that designs of an order that is logarithmic in the dimension maximize all Rényi entanglement entropies and so are completely random in terms of the entanglement spectrum. Our results relate the behaviors of Rényi entanglement entropies to the complexity of scrambling and quantum chaos in terms of the degree of randomness, and suggest a generalization of the fast scrambling conjecture.

Symmetry Transition Preserving Chirality in QCD: A Versatile Random Matrix Model

NASA Astrophysics Data System (ADS)

Kanazawa, Takuya; Kieburg, Mario

2018-06-01

We consider a random matrix model which interpolates between the chiral Gaussian unitary ensemble and the Gaussian unitary ensemble while preserving chiral symmetry. This ensemble describes flavor symmetry breaking for staggered fermions in 3D QCD as well as in 4D QCD at high temperature or in 3D QCD at a finite isospin chemical potential. Our model is an Osborn-type two-matrix model which is equivalent to the elliptic ensemble but we consider the singular value statistics rather than the complex eigenvalue statistics. We report on exact results for the partition function and the microscopic level density of the Dirac operator in the ɛ regime of QCD. We compare these analytical results with Monte Carlo simulations of the matrix model.

CMV matrices in random matrix theory and integrable systems: a survey

NASA Astrophysics Data System (ADS)

Nenciu, Irina

2006-07-01

We present a survey of recent results concerning a remarkable class of unitary matrices, the CMV matrices. We are particularly interested in the role they play in the theory of random matrices and integrable systems. Throughout the paper we also emphasize the analogies and connections to Jacobi matrices.

Constructing acoustic timefronts using random matrix theory.

PubMed

Hegewisch, Katherine C; Tomsovic, Steven

2013-10-01

In a recent letter [Hegewisch and Tomsovic, Europhys. Lett. 97, 34002 (2012)], random matrix theory is introduced for long-range acoustic propagation in the ocean. The theory is expressed in terms of unitary propagation matrices that represent the scattering between acoustic modes due to sound speed fluctuations induced by the ocean's internal waves. The scattering exhibits a power-law decay as a function of the differences in mode numbers thereby generating a power-law, banded, random unitary matrix ensemble. This work gives a more complete account of that approach and extends the methods to the construction of an ensemble of acoustic timefronts. The result is a very efficient method for studying the statistical properties of timefronts at various propagation ranges that agrees well with propagation based on the parabolic equation. It helps identify which information about the ocean environment can be deduced from the timefronts and how to connect features of the data to that environmental information. It also makes direct connections to methods used in other disordered waveguide contexts where the use of random matrix theory has a multi-decade history.

Quantum state matching of qubits via measurement-induced nonlinear transformations

NASA Astrophysics Data System (ADS)

Kálmán, Orsolya; Kiss, Tamás

2018-03-01

We consider the task of deciding whether an unknown qubit state falls in a prescribed neighborhood of a reference state. We assume that several copies of the unknown state are given and apply a unitary operation pairwise on them combined with a postselection scheme conditioned on the measurement result obtained on one of the qubits of the pair. The resulting transformation is a deterministic, nonlinear, chaotic map in the Hilbert space. We derive a class of these transformations capable of orthogonalizing nonorthogonal qubit states after a few iterations. These nonlinear maps orthogonalize states which correspond to the two different convergence regions of the nonlinear map. Based on the analysis of the border (the so-called Julia set) between the two regions of convergence, we show that it is always possible to find a map capable of deciding whether an unknown state is within a neighborhood of fixed radius around a desired quantum state. We analyze which one- and two-qubit operations would physically realize the scheme. It is possible to find a single two-qubit unitary gate for each map or, alternatively, a universal special two-qubit gate together with single-qubit gates in order to carry out the task. We note that it is enough to have a single physical realization of the required gates due to the iterative nature of the scheme.

Entanglement loss in molecular quantum-dot qubits due to interaction with the environment.

PubMed

Blair, Enrique P; Tóth, Géza; Lent, Craig S

2018-05-16

We study quantum entanglement loss due to environmental interaction in a condensed matter system with a complex geometry relevant to recent proposals for computing with single electrons at the nanoscale. We consider a system consisting of two qubits, each realized by an electron in a double quantum dot, which are initially in an entangled Bell state. The qubits are widely separated and each interacts with its own environment. The environment for each is modeled by surrounding double quantum dots placed at random positions with random orientations. We calculate the unitary evolution of the joint system and environment. The global state remains pure throughout. We examine the time dependence of the expectation value of the bipartite Clauser-Horne-Shimony-Holt (CHSH) and Brukner-Paunković-Rudolph-Vedral (BPRV) Bell operators and explore the emergence of correlations consistent with local realism. Though the details of this transition depend on the specific environmental geometry, we show how the results can be mapped on to a universal behavior with appropriate scaling. We determine the relevant disentanglement times based on realistic physical parameters for molecular double-dots.

Entanglement loss in molecular quantum-dot qubits due to interaction with the environment

NASA Astrophysics Data System (ADS)

Blair, Enrique P.; Tóth, Géza; Lent, Craig S.

2018-05-01

We study quantum entanglement loss due to environmental interaction in a condensed matter system with a complex geometry relevant to recent proposals for computing with single electrons at the nanoscale. We consider a system consisting of two qubits, each realized by an electron in a double quantum dot, which are initially in an entangled Bell state. The qubits are widely separated and each interacts with its own environment. The environment for each is modeled by surrounding double quantum dots placed at random positions with random orientations. We calculate the unitary evolution of the joint system and environment. The global state remains pure throughout. We examine the time dependence of the expectation value of the bipartite Clauser–Horne–Shimony–Holt (CHSH) and Brukner–Paunković–Rudolph–Vedral (BPRV) Bell operators and explore the emergence of correlations consistent with local realism. Though the details of this transition depend on the specific environmental geometry, we show how the results can be mapped on to a universal behavior with appropriate scaling. We determine the relevant disentanglement times based on realistic physical parameters for molecular double-dots.

Universal Scaling Laws in the Dynamics of a Homogeneous Unitary Bose Gas

NASA Astrophysics Data System (ADS)

Eigen, Christoph; Glidden, Jake A. P.; Lopes, Raphael; Navon, Nir; Hadzibabic, Zoran; Smith, Robert P.

2017-12-01

We study the dynamics of an initially degenerate homogeneous Bose gas after an interaction quench to the unitary regime at a magnetic Feshbach resonance. As the cloud decays and heats, it exhibits a crossover from degenerate- to thermal-gas behavior, both of which are characterized by universal scaling laws linking the particle-loss rate to the total atom number N . In the degenerate and thermal regimes, the per-particle loss rate is ∝N2 /3 and N26 /9, respectively. The crossover occurs at a universal kinetic energy per particle and at a universal time after the quench, in units of energy and time set by the gas density. By slowly sweeping the magnetic field away from the resonance and creating a mixture of atoms and molecules, we also map out the dynamics of correlations in the unitary gas, which display a universal temporal scaling with the gas density, and reach a steady state while the gas is still degenerate.

Universal Scaling Laws in the Dynamics of a Homogeneous Unitary Bose Gas.

PubMed

Eigen, Christoph; Glidden, Jake A P; Lopes, Raphael; Navon, Nir; Hadzibabic, Zoran; Smith, Robert P

2017-12-22

We study the dynamics of an initially degenerate homogeneous Bose gas after an interaction quench to the unitary regime at a magnetic Feshbach resonance. As the cloud decays and heats, it exhibits a crossover from degenerate- to thermal-gas behavior, both of which are characterized by universal scaling laws linking the particle-loss rate to the total atom number N. In the degenerate and thermal regimes, the per-particle loss rate is ∝N^{2/3} and N^{26/9}, respectively. The crossover occurs at a universal kinetic energy per particle and at a universal time after the quench, in units of energy and time set by the gas density. By slowly sweeping the magnetic field away from the resonance and creating a mixture of atoms and molecules, we also map out the dynamics of correlations in the unitary gas, which display a universal temporal scaling with the gas density, and reach a steady state while the gas is still degenerate.

Embedded Gaussian unitary ensembles with U(Ω)⊗SU(r) embedding generated by random two-body interactions with SU(r) symmetry

NASA Astrophysics Data System (ADS)

Vyas, Manan; Kota, V. K. B.

2012-12-01

Following the earlier studies on embedded unitary ensembles generated by random two-body interactions [EGUE(2)] with spin SU(2) and spin-isospin SU(4) symmetries, developed is a general formulation, for deriving lower order moments of the one- and two-point correlation functions in eigenvalues, that is valid for any EGUE(2) and BEGUE(2) ("B" stands for bosons) with U(Ω)⊗SU(r) embedding and with two-body interactions preserving SU(r) symmetry. Using this formulation with r = 1, we recover the results derived by Asaga et al. [Ann. Phys. (N.Y.) 297, 344 (2002)], 10.1006/aphy.2002.6248 for spinless boson systems. Going further, new results are obtained for r = 2 (this corresponds to two species boson systems) and r = 3 (this corresponds to spin 1 boson systems).

Chaos and random matrices in supersymmetric SYK

NASA Astrophysics Data System (ADS)

Hunter-Jones, Nicholas; Liu, Junyu

2018-05-01

We use random matrix theory to explore late-time chaos in supersymmetric quantum mechanical systems. Motivated by the recent study of supersymmetric SYK models and their random matrix classification, we consider the Wishart-Laguerre unitary ensemble and compute the spectral form factors and frame potentials to quantify chaos and randomness. Compared to the Gaussian ensembles, we observe the absence of a dip regime in the form factor and a slower approach to Haar-random dynamics. We find agreement between our random matrix analysis and predictions from the supersymmetric SYK model, and discuss the implications for supersymmetric chaotic systems.

Quantum Search in Hilbert Space

NASA Technical Reports Server (NTRS)

Zak, Michail

2003-01-01

A proposed quantum-computing algorithm would perform a search for an item of information in a database stored in a Hilbert-space memory structure. The algorithm is intended to make it possible to search relatively quickly through a large database under conditions in which available computing resources would otherwise be considered inadequate to perform such a task. The algorithm would apply, more specifically, to a relational database in which information would be stored in a set of N complex orthonormal vectors, each of N dimensions (where N can be exponentially large). Each vector would constitute one row of a unitary matrix, from which one would derive the Hamiltonian operator (and hence the evolutionary operator) of a quantum system. In other words, all the stored information would be mapped onto a unitary operator acting on a quantum state that would represent the item of information to be retrieved. Then one could exploit quantum parallelism: one could pose all search queries simultaneously by performing a quantum measurement on the system. In so doing, one would effectively solve the search problem in one computational step. One could exploit the direct- and inner-product decomposability of the unitary matrix to make the dimensionality of the memory space exponentially large by use of only linear resources. However, inasmuch as the necessary preprocessing (the mapping of the stored information into a Hilbert space) could be exponentially expensive, the proposed algorithm would likely be most beneficial in applications in which the resources available for preprocessing were much greater than those available for searching.

On multivariate trace inequalities of Sutter, Berta, and Tomamichel

NASA Astrophysics Data System (ADS)

Lemm, Marius

2018-01-01

We consider a family of multivariate trace inequalities recently derived by Sutter, Berta, and Tomamichel. These inequalities generalize the Golden-Thompson inequality and Lieb's triple matrix inequality to an arbitrary number of matrices in a way that features complex matrix powers (i.e., certain unitaries). We show that their inequalities can be rewritten as an n-matrix generalization of Lieb's original triple matrix inequality. The complex matrix powers are replaced by resolvents and appropriate maximally entangled states. We expect that the technically advantageous properties of resolvents, in particular for perturbation theory, can be of use in applications of the n-matrix inequalities, e.g., for analyzing the performance of the rotated Petz recovery map in quantum information theory and for removing the unitaries altogether.

Quantum control and quantum tomography on neutral atom qudits

NASA Astrophysics Data System (ADS)

Sosa Martinez, Hector

Neutral atom systems are an appealing platform for the development and testing of quantum control and measurement techniques. This dissertation presents experimental investigations of control and measurement tools using as a testbed the 16-dimensional hyperfine manifold associated with the electronic ground state of cesium atoms. On the control side, we present an experimental realization of a protocol to implement robust unitary transformations in the presence of static and dynamic perturbations. We also present an experimental realization of inhomogeneous quantum control. Specifically, we demonstrate our ability to perform two different unitary transformations on atoms that see different light shifts from an optical addressing field. On the measurement side, we present experimental realizations of quantum state and process tomography. The state tomography project encompasses a comprehensive evaluation of several measurement strategies and state estimation algorithms. Our experimental results show that in the presence of experimental imperfections, there is a clear tradeoff between accuracy, efficiency and robustness in the reconstruction. The process tomography project involves an experimental demonstration of efficient reconstruction by using a set of intelligent probe states. Experimental results show that we are able to reconstruct unitary maps in Hilbert spaces with dimension ranging from d=4 to d=16. To the best of our knowledge, this is the first time that a unitary process in d=16 is successfully reconstructed in the laboratory.

Quantum resonances and regularity islands in quantum maps

PubMed

Sokolov; Zhirov; Alonso; Casati

2000-05-01

We study analytically as well as numerically the dynamics of a quantum map near a quantum resonance of an order q. The map is embedded into a continuous unitary transformation generated by a time-independent quasi-Hamiltonian. Such a Hamiltonian generates at the very point of the resonance a local gauge transformation described by the unitary unimodular group SU(q). The resonant energy growth is attributed to the zero Liouville eigenmodes of the generator in the adjoint representation of the group while the nonzero modes yield saturating with time contribution. In a vicinity of a given resonance, the quasi-Hamiltonian is then found in the form of power expansion with respect to the detuning from the resonance. The problem is related in this way to the motion along a circle in a (q2 - 1)-component inhomogeneous "magnetic" field of a quantum particle with q intrinsic degrees of freedom described by the SU(q) group. This motion is in parallel with the classical phase oscillations near a nonlinear resonance. The most important role is played by the resonances with the orders much smaller than the typical localization length q < l. Such resonances master for exponentially long though finite times the motion in some domains around them. Explicit analytical solution is possible for a few lowest and strongest resonances.

Restricted numerical range: A versatile tool in the theory of quantum information

NASA Astrophysics Data System (ADS)

Gawron, Piotr; Puchała, Zbigniew; Miszczak, Jarosław Adam; Skowronek, Łukasz; Życzkowski, Karol

2010-10-01

Numerical range of a Hermitian operator X is defined as the set of all possible expectation values of this observable among a normalized quantum state. We analyze a modification of this definition in which the expectation value is taken among a certain subset of the set of all quantum states. One considers, for instance, the set of real states, the set of product states, separable states, or the set of maximally entangled states. We show exemplary applications of these algebraic tools in the theory of quantum information: analysis of k-positive maps and entanglement witnesses, as well as study of the minimal output entropy of a quantum channel. Product numerical range of a unitary operator is used to solve the problem of local distinguishability of a family of two unitary gates.

Open quantum random walk in terms of quantum Bernoulli noise

NASA Astrophysics Data System (ADS)

Wang, Caishi; Wang, Ce; Ren, Suling; Tang, Yuling

2018-03-01

In this paper, we introduce an open quantum random walk, which we call the QBN-based open walk, by means of quantum Bernoulli noise, and study its properties from a random walk point of view. We prove that, with the localized ground state as its initial state, the QBN-based open walk has the same limit probability distribution as the classical random walk. We also show that the probability distributions of the QBN-based open walk include those of the unitary quantum walk recently introduced by Wang and Ye (Quantum Inf Process 15:1897-1908, 2016) as a special case.

C*-algebras associated with reversible extensions of logistic maps

NASA Astrophysics Data System (ADS)

Kwaśniewski, Bartosz K.

2012-10-01

The construction of reversible extensions of dynamical systems presented in a previous paper by the author and A.V. Lebedev is enhanced, so that it applies to arbitrary mappings (not necessarily with open range). It is based on calculating the maximal ideal space of C*-algebras that extends endomorphisms to partial automorphisms via partial isometric representations, and involves a new set of 'parameters' (the role of parameters is played by chosen sets or ideals). As model examples, we give a thorough description of reversible extensions of logistic maps and a classification of systems associated with compression of unitaries generating homeomorphisms of the circle. Bibliography: 34 titles.

Random Matrix Approach to Quantum Adiabatic Evolution Algorithms

NASA Technical Reports Server (NTRS)

Boulatov, Alexei; Smelyanskiy, Vadier N.

2004-01-01

We analyze the power of quantum adiabatic evolution algorithms (Q-QA) for solving random NP-hard optimization problems within a theoretical framework based on the random matrix theory (RMT). We present two types of the driven RMT models. In the first model, the driving Hamiltonian is represented by Brownian motion in the matrix space. We use the Brownian motion model to obtain a description of multiple avoided crossing phenomena. We show that the failure mechanism of the QAA is due to the interaction of the ground state with the "cloud" formed by all the excited states, confirming that in the driven RMT models. the Landau-Zener mechanism of dissipation is not important. We show that the QAEA has a finite probability of success in a certain range of parameters. implying the polynomial complexity of the algorithm. The second model corresponds to the standard QAEA with the problem Hamiltonian taken from the Gaussian Unitary RMT ensemble (GUE). We show that the level dynamics in this model can be mapped onto the dynamics in the Brownian motion model. However, the driven RMT model always leads to the exponential complexity of the algorithm due to the presence of the long-range intertemporal correlations of the eigenvalues. Our results indicate that the weakness of effective transitions is the leading effect that can make the Markovian type QAEA successful.

High-Threshold Low-Overhead Fault-Tolerant Classical Computation and the Replacement of Measurements with Unitary Quantum Gates.

PubMed

Cruikshank, Benjamin; Jacobs, Kurt

2017-07-21

von Neumann's classic "multiplexing" method is unique in achieving high-threshold fault-tolerant classical computation (FTCC), but has several significant barriers to implementation: (i) the extremely complex circuits required by randomized connections, (ii) the difficulty of calculating its performance in practical regimes of both code size and logical error rate, and (iii) the (perceived) need for large code sizes. Here we present numerical results indicating that the third assertion is false, and introduce a novel scheme that eliminates the two remaining problems while retaining a threshold very close to von Neumann's ideal of 1/6. We present a simple, highly ordered wiring structure that vastly reduces the circuit complexity, demonstrates that randomization is unnecessary, and provides a feasible method to calculate the performance. This in turn allows us to show that the scheme requires only moderate code sizes, vastly outperforms concatenation schemes, and under a standard error model a unitary implementation realizes universal FTCC with an accuracy threshold of p<5.5%, in which p is the error probability for 3-qubit gates. FTCC is a key component in realizing measurement-free protocols for quantum information processing. In view of this, we use our scheme to show that all-unitary quantum circuits can reproduce any measurement-based feedback process in which the asymptotic error probabilities for the measurement and feedback are (32/63)p≈0.51p and 1.51p, respectively.

Localization of Unitary Braid Group Representations

NASA Astrophysics Data System (ADS)

Rowell, Eric C.; Wang, Zhenghan

2012-05-01

Governed by locality, we explore a connection between unitary braid group representations associated to a unitary R-matrix and to a simple object in a unitary braided fusion category. Unitary R-matrices, namely unitary solutions to the Yang-Baxter equation, afford explicitly local unitary representations of braid groups. Inspired by topological quantum computation, we study whether or not it is possible to reassemble the irreducible summands appearing in the unitary braid group representations from a unitary braided fusion category with possibly different positive multiplicities to get representations that are uniformly equivalent to the ones from a unitary R-matrix. Such an equivalence will be called a localization of the unitary braid group representations. We show that the q = e π i/6 specialization of the unitary Jones representation of the braid groups can be localized by a unitary 9 × 9 R-matrix. Actually this Jones representation is the first one in a family of theories ( SO( N), 2) for an odd prime N > 1, which are conjectured to be localizable. We formulate several general conjectures and discuss possible connections to physics and computer science.

Effects of a Meditation Program on Nurses' Power and Quality of Life.

PubMed

Chang, Sun Ju; Kwak, Eun Young; Hahm, Bong-Jin; Seo, Se Hee; Lee, Da Woon; Jang, Sun Joo

2016-07-01

This study evaluated the effects of meditation programs on nurses' power and quality of life. In this study, Barrett's power theory derived from Rogers' unitary human being science was used as a theoretical framework. A randomized controlled design with 50 recruited and randomly allocated participants was used. The results demonstrated that the eight-week meditation program significantly improved nurses' power and quality of life. These results suggest that meditation has positive effects on power and quality of life. © The Author(s) 2016.

Comparison of unitary associations and probabilistic ranking and scaling as applied to mesozoic radiolarians

NASA Astrophysics Data System (ADS)

Baumgartner, Peter O.

A database on Middle Jurassic-Early Cretaceous radiolarians consisting of first and final occurrences of 110 species in 226 samples from 43 localities was used to compute Unitary Associations and probabilistic ranking and scaling (RASC), in order to test deterministic versus probabilistic quantitative biostratigraphic methods. Because the Mesozoic radiolarian fossil record is mainly dissolution-controlled, the sequence of events differs greatly from section to section. The scatter of local first and final appearances along a time scale is large compared to the species range; it is asymmetrical, with a maximum near the ends of the range and it is non-random. Thus, these data do not satisfy the statistical assumptions made in ranking and scaling. Unitary Associations produce maximum ranges of the species relative to each other by stacking cooccurrence data from all sections and therefore compensate for the local dissolution effects. Ranking and scaling, based on the assumption of a normal random distribution of the events, produces average ranges which are for most species much shorter than the maximum UA-ranges. There are, however, a number of species with similar ranges in both solutions. These species are believed to be the most dissolution-resistant and, therefore, the most reliable ones for the definition of biochronozones. The comparison of maximum and average ranges may be a powerful tool to test reliability of species for biochronology. Dissolution-controlled fossil data yield high crossover frequencies and therefore small, statistically insignificant interfossil distances. Scaling has not produced a useful sequence for this type of data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwasniewski, Bartosz K

The construction of reversible extensions of dynamical systems presented in a previous paper by the author and A.V. Lebedev is enhanced, so that it applies to arbitrary mappings (not necessarily with open range). It is based on calculating the maximal ideal space of C*-algebras that extends endomorphisms to partial automorphisms via partial isometric representations, and involves a new set of 'parameters' (the role of parameters is played by chosen sets or ideals). As model examples, we give a thorough description of reversible extensions of logistic maps and a classification of systems associated with compression of unitaries generating homeomorphisms of themore » circle. Bibliography: 34 titles.« less

G-Consistent Subsets and Reduced Dynamical Quantum Maps

NASA Astrophysics Data System (ADS)

Ceballos, Russell R.

A quantum system which evolves in time while interacting with an external environ- ment is said to be an open quantum system (OQS), and the influence of the environment on the unperturbed unitary evolution of the system generally leads to non-unitary dynamics. This kind of open system dynamical evolution has been typically modeled by a Standard Prescription (SP) which assumes that the state of the OQS is initially uncorrelated with the environment state. It is here shown that when a minimal set of physically motivated assumptions are adopted, not only does there exist constraints on the reduced dynamics of an OQS such that this SP does not always accurately describe the possible initial cor- relations existing between the OQS and environment, but such initial correlations, and even entanglement, can be witnessed when observing a particular class of reduced state transformations termed purity extractions are observed. Furthermore, as part of a more fundamental investigation to better understand the minimal set of assumptions required to formulate well defined reduced dynamical quantum maps, it is demonstrated that there exists a one-to-one correspondence between the set of initial reduced states and the set of admissible initial system-environment composite states when G-consistency is enforced. Given the discussions surrounding the requirement of complete positivity and the reliance on the SP, the results presented here may well be found valuable for determining the ba- sic properties of reduced dynamical maps, and when restrictions on the OQS dynamics naturally emerge.

Almost all quantum channels are equidistant

NASA Astrophysics Data System (ADS)

Nechita, Ion; Puchała, Zbigniew; Pawela, Łukasz; Życzkowski, Karol

2018-05-01

In this work, we analyze properties of generic quantum channels in the case of large system size. We use random matrix theory and free probability to show that the distance between two independent random channels converges to a constant value as the dimension of the system grows larger. As a measure of the distance we use the diamond norm. In the case of a flat Hilbert-Schmidt distribution on quantum channels, we obtain that the distance converges to 1/2 +2/π , giving also an estimate for the maximum success probability for distinguishing the channels. We also consider the problem of distinguishing two random unitary rotations.

Breaking time reversal in a simple smooth chaotic system.

PubMed

Tomsovic, Steven; Ullmo, Denis; Nagano, Tatsuro

2003-06-01

Within random matrix theory, the statistics of the eigensolutions depend fundamentally on the presence (or absence) of time reversal symmetry. Accepting the Bohigas-Giannoni-Schmit conjecture, this statement extends to quantum systems with chaotic classical analogs. For practical reasons, much of the supporting numerical studies of symmetry breaking have been done with billiards or maps, and little with simple, smooth systems. There are two main difficulties in attempting to break time reversal invariance in a continuous time system with a smooth potential. The first is avoiding false time reversal breaking. The second is locating a parameter regime in which the symmetry breaking is strong enough to transform the fluctuation properties fully to the broken symmetry case, and yet remain weak enough so as not to regularize the dynamics sufficiently that the system is no longer chaotic. We give an example of a system of two coupled quartic oscillators whose energy level statistics closely match with those of the Gaussian unitary ensemble, and which possesses only a minor proportion of regular motion in its phase space.

Unitary Root Music and Unitary Music with Real-Valued Rank Revealing Triangular Factorization

DTIC Science & Technology

2010-06-01

AFRL-RY-WP-TP-2010-1213 UNITARY ROOT MUSIC AND UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) Nizar...DATES COVERED (From - To) June 2010 Journal Article Postprint 08 September 2006 – 31 August 2009 4. TITLE AND SUBTITLE UNITARY ROOT MUSIC AND...UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA8650-05-D-1912-0007 5c

Multiresolution saliency map based object segmentation

NASA Astrophysics Data System (ADS)

Yang, Jian; Wang, Xin; Dai, ZhenYou

2015-11-01

Salient objects' detection and segmentation are gaining increasing research interest in recent years. A saliency map can be obtained from different models presented in previous studies. Based on this saliency map, the most salient region (MSR) in an image can be extracted. This MSR, generally a rectangle, can be used as the initial parameters for object segmentation algorithms. However, to our knowledge, all of those saliency maps are represented in a unitary resolution although some models have even introduced multiscale principles in the calculation process. Furthermore, some segmentation methods, such as the well-known GrabCut algorithm, need more iteration time or additional interactions to get more precise results without predefined pixel types. A concept of a multiresolution saliency map is introduced. This saliency map is provided in a multiresolution format, which naturally follows the principle of the human visual mechanism. Moreover, the points in this map can be utilized to initialize parameters for GrabCut segmentation by labeling the feature pixels automatically. Both the computing speed and segmentation precision are evaluated. The results imply that this multiresolution saliency map-based object segmentation method is simple and efficient.

Parallel regulation of feedforward inhibition and excitation during whisker map plasticity

PubMed Central

House, David RC; Elstrott, Justin; Koh, Eileen; Chung, Jason; Feldman, Daniel E.

2011-01-01

Sensory experience drives robust plasticity of sensory maps in cerebral cortex, but the role of inhibitory circuits in this process is not fully understood. We show that classical deprivation-induced whisker map plasticity in layer 2/3 (L2/3) of rat somatosensory (S1) cortex involves robust weakening of L4-L2/3 feedforward inhibition. This weakening was caused by reduced L4 excitation onto L2/3 fast-spiking (FS) interneurons, which mediate sensitive feedforward inhibition, and was partially offset by strengthening of unitary FS to L2/3 pyramidal cell synapses. Weakening of feedforward inhibition paralleled the known weakening of feedforward excitation, so that mean excitatory-inhibitory balance and timing onto L2/3 pyramidal cells were preserved. Thus, reduced feedforward inhibition is a covert compensatory process that can maintain excitatory-inhibitory balance during classical deprivation-induced Hebbian map plasticity. PMID:22153377

Implementability of two-qubit unitary operations over the butterfly network and the ladder network with free classical communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akibue, Seiseki; Murao, Mio

2014-12-04

We investigate distributed implementation of two-qubit unitary operations over two primitive networks, the butterfly network and the ladder network, as a first step to apply network coding for quantum computation. By classifying two-qubit unitary operations in terms of the Kraus-Cirac number, the number of non-zero parameters describing the global part of two-qubit unitary operations, we analyze which class of two-qubit unitary operations is implementable over these networks with free classical communication. For the butterfly network, we show that two classes of two-qubit unitary operations, which contain all Clifford, controlled-unitary and matchgate operations, are implementable over the network. For the laddermore » network, we show that two-qubit unitary operations are implementable over the network if and only if their Kraus-Cirac number do not exceed the number of the bridges of the ladder.« less

Quantumness-generating capability of quantum dynamics

NASA Astrophysics Data System (ADS)

Li, Nan; Luo, Shunlong; Mao, Yuanyuan

2018-04-01

We study quantumness-generating capability of quantum dynamics, where quantumness refers to the noncommutativity between the initial state and the evolving state. In terms of the commutator of the square roots of the initial state and the evolving state, we define a measure to quantify the quantumness-generating capability of quantum dynamics with respect to initial states. Quantumness-generating capability is absent in classical dynamics and hence is a fundamental characteristic of quantum dynamics. For qubit systems, we present an analytical form for this measure, by virtue of which we analyze several prototypical dynamics such as unitary dynamics, phase damping dynamics, amplitude damping dynamics, and random unitary dynamics (Pauli channels). Necessary and sufficient conditions for the monotonicity of quantumness-generating capability are also identified. Finally, we compare these conditions for the monotonicity of quantumness-generating capability with those for various Markovianities and illustrate that quantumness-generating capability and quantum Markovianity are closely related, although they capture different aspects of quantum dynamics.

Unitary Suprathreshold Color-Difference Metrics of Legibility for CRT Raster Imagery.

DTIC Science & Technology

1986-09-01

observers possessing norma vision could accurately read random numeral strings of one color displayed DD J 4-73 EDITION OF C 6S IS OBSOLETE - SEURT CLSIICTO...34 Table 2, continued. SAE (L*,u*,v*) : .909 .940 Intercept 1. 8581 1. 8022 " N -0. 3980 -0.3655 m .AE 0. 1217 0. 1206-" =, E -0. 0019 -0. 0017 * all t > 3

Parametric Quantum Search Algorithm as Quantum Walk: A Quantum Simulation

NASA Astrophysics Data System (ADS)

Ellinas, Demosthenes; Konstandakis, Christos

2016-02-01

Parametric quantum search algorithm (PQSA) is a form of quantum search that results by relaxing the unitarity of the original algorithm. PQSA can naturally be cast in the form of quantum walk, by means of the formalism of oracle algebra. This is due to the fact that the completely positive trace preserving search map used by PQSA, admits a unitarization (unitary dilation) a la quantum walk, at the expense of introducing auxiliary quantum coin-qubit space. The ensuing QW describes a process of spiral motion, chosen to be driven by two unitary Kraus generators, generating planar rotations of Bloch vector around an axis. The quadratic acceleration of quantum search translates into an equivalent quadratic saving of the number of coin qubits in the QW analogue. The associated to QW model Hamiltonian operator is obtained and is shown to represent a multi-particle long-range interacting quantum system that simulates parametric search. Finally, the relation of PQSA-QW simulator to the QW search algorithm is elucidated.

On the homotopy equivalence of simple AI-algebras

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aristov, O Yu

1999-02-28

Let A and B be simple unital AI-algebras (an AI-algebra is an inductive limit of C*-algebras of the form BigOplus{sub i}{sup k}C([0,1],M{sub N{sub i}}). It is proved that two arbitrary unital homomorphisms from A into B such that the corresponding maps K{sub 0}A{yields}K{sub 0}B coincide are homotopic. Necessary and sufficient conditions on the Elliott invariant for A and B to be homotopy equivalent are indicated. Moreover, two algebras in the above class having the same K-theory but not homotopy equivalent are constructed. A theorem on the homotopy of approximately unitarily equivalent homomorphisms between AI-algebras is used in the proof, whichmore » is deduced in its turn from a generalization to the case of AI-algebras of a theorem of Manuilov stating that a unitary matrix almost commuting with a self-adjoint matrix h can be joined to 1 by a continuous path consisting of unitary matrices almost commuting with h.« less

Work distributions for random sudden quantum quenches

NASA Astrophysics Data System (ADS)

Łobejko, Marcin; Łuczka, Jerzy; Talkner, Peter

2017-05-01

The statistics of work performed on a system by a sudden random quench is investigated. Considering systems with finite dimensional Hilbert spaces we model a sudden random quench by randomly choosing elements from a Gaussian unitary ensemble (GUE) consisting of Hermitian matrices with identically, Gaussian distributed matrix elements. A probability density function (pdf) of work in terms of initial and final energy distributions is derived and evaluated for a two-level system. Explicit results are obtained for quenches with a sharply given initial Hamiltonian, while the work pdfs for quenches between Hamiltonians from two independent GUEs can only be determined in explicit form in the limits of zero and infinite temperature. The same work distribution as for a sudden random quench is obtained for an adiabatic, i.e., infinitely slow, protocol connecting the same initial and final Hamiltonians.

Generalized Weyl-Wigner map and Vey quantum mechanics

NASA Astrophysics Data System (ADS)

Dias, Nuno Costa; Prata, João Nuno

2001-12-01

The Weyl-Wigner map yields the entire structure of Moyal quantum mechanics directly from the standard operator formulation. The covariant generalization of Moyal theory, also known as Vey quantum mechanics, was presented in the literature many years ago. However, a derivation of the formalism directly from standard operator quantum mechanics, clarifying the relation between the two formulations, is still missing. In this article we present a covariant generalization of the Weyl order prescription and of the Weyl-Wigner map and use them to derive Vey quantum mechanics directly from the standard operator formulation. The procedure displays some interesting features: it yields all the key ingredients and provides a more straightforward interpretation of the Vey theory including a direct implementation of unitary operator transformations as phase space coordinate transformations in the Vey idiom. These features are illustrated through a simple example.

Symmetry breaking in tensor models

NASA Astrophysics Data System (ADS)

Benedetti, Dario; Gurau, Razvan

2015-11-01

In this paper we analyze a quartic tensor model with one interaction for a tensor of arbitrary rank. This model has a critical point where a continuous limit of infinitely refined random geometries is reached. We show that the critical point corresponds to a phase transition in the tensor model associated to a breaking of the unitary symmetry. We analyze the model in the two phases and prove that, in a double scaling limit, the symmetric phase corresponds to a theory of infinitely refined random surfaces, while the broken phase corresponds to a theory of infinitely refined random nodal surfaces. At leading order in the double scaling limit planar surfaces dominate in the symmetric phase, and planar nodal surfaces dominate in the broken phase.

Discrete Painlevé equations for a class of PVI τ-functions given as U(N) averages

NASA Astrophysics Data System (ADS)

Forrester, P. J.; Witte, N. S.

2005-09-01

In a recent work, difference equations (Laguerre-Freud equations) for the bi-orthogonal polynomials and related quantities corresponding to the weight on the unit circle w(z)=\\prod^m_{j=1}(z-z_j(t))^{\\rho_j} were derived. It is shown here that in the case m = 3, these difference equations, when applied to the calculation of the underlying U(N) average, reduce to a coupled system identifiable with that obtained by Adler and van Moerbeke, using the methods of the Toeplitz lattice and Virasoro constraints. Moreover, it is shown that this coupled system can be reduced to yield the discrete fifth Painlevé equation dPV as it occurs in the theory of the sixth Painlevé system. Methods based on affine Weyl group symmetries of Bäcklund transformations have previously yielded the dPV equation, but with different parameters for the same problem. We find an explicit mapping between the two forms. Applications of our results are made to give recurrences for the gap probabilities and moments in the circular unitary ensemble of random matrices, and to the diagonal spin-spin correlation function of the square lattice Ising model.

Dissipation, dephasing and quantum Darwinism in qubit systems with random unitary interactions

NASA Astrophysics Data System (ADS)

Balaneskovic, Nenad; Mendler, Marc

2016-09-01

We investigate the influence of dissipation and decoherence on quantum Darwinism by generalizing Zurek's original qubit model of decoherence and the establishment of pointer states [W.H. Zurek, Nat. Phys. 5, 181 (2009); see also arXiv: quant-ph/0707.2832v1, pp. 14-19.]. Our model allows for repeated multiple qubit-qubit couplings between system and environment which are described by randomly applied two-qubit quantum operations inducing entanglement, dissipation and dephasing. The resulting stationary qubit states of system and environment are investigated. They exhibit the intricate influence of entanglement generation, dissipation and dephasing on this characteristic quantum phenomenon.

Quantum computation over the butterfly network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soeda, Akihito; Kinjo, Yoshiyuki; Turner, Peter S.

2011-07-15

In order to investigate distributed quantum computation under restricted network resources, we introduce a quantum computation task over the butterfly network where both quantum and classical communications are limited. We consider deterministically performing a two-qubit global unitary operation on two unknown inputs given at different nodes, with outputs at two distinct nodes. By using a particular resource setting introduced by M. Hayashi [Phys. Rev. A 76, 040301(R) (2007)], which is capable of performing a swap operation by adding two maximally entangled qubits (ebits) between the two input nodes, we show that unitary operations can be performed without adding any entanglementmore » resource, if and only if the unitary operations are locally unitary equivalent to controlled unitary operations. Our protocol is optimal in the sense that the unitary operations cannot be implemented if we relax the specifications of any of the channels. We also construct protocols for performing controlled traceless unitary operations with a 1-ebit resource and for performing global Clifford operations with a 2-ebit resource.« less

Neural correlates of economic game playing.

PubMed

Krueger, Frank; Grafman, Jordan; McCabe, Kevin

2008-12-12

The theory of games provides a mathematical formalization of strategic choices, which have been studied in both economics and neuroscience, and more recently has become the focus of neuroeconomics experiments with human and non-human actors. This paper reviews the results from a number of game experiments that establish a unitary system for forming subjective expected utility maps in the brain, and acting on these maps to produce choices. Social situations require the brain to build an understanding of the other person using neuronal mechanisms that share affective and intentional mental states. These systems allow subjects to better predict other players' choices, and allow them to modify their subjective utility maps to value pro-social strategies. New results for a trust game are presented, which show that the trust relationship includes systems common to both trusting and trustworthy behaviour, but they also show that the relative temporal positions of first and second players require computations unique to that role.

Meditations on the unitary rhythm of dying-grieving.

PubMed

Malinski, Violet M

2012-07-01

When someone faces loss of a loved one, that person simultaneously grieves and dies a little, just as the one dying also grieves. The author's personal conceptualization of dying and grieving as a unitary rhythm is explored based primarily on her interpretation of Rogers' science of unitary human beings, along with selected examples from related nursing literature and from the emerging focus on continuing bonds in other disciplines. Examples from contemporary songwriters that depict such a unitary conceptualization are given along with personal examples. The author concludes with her description of the unitary rhythm of dying-grieving.

Analytical results for the statistical distribution related to a memoryless deterministic walk: dimensionality effect and mean-field models.

PubMed

Terçariol, César Augusto Sangaletti; Martinez, Alexandre Souto

2005-08-01

Consider a medium characterized by N points whose coordinates are randomly generated by a uniform distribution along the edges of a unitary d-dimensional hypercube. A walker leaves from each point of this disordered medium and moves according to the deterministic rule to go to the nearest point which has not been visited in the preceding mu steps (deterministic tourist walk). Each trajectory generated by this dynamics has an initial nonperiodic part of t steps (transient) and a final periodic part of p steps (attractor). The neighborhood rank probabilities are parametrized by the normalized incomplete beta function Id= I1/4 [1/2, (d+1) /2] . The joint distribution S(N) (mu,d) (t,p) is relevant, and the marginal distributions previously studied are particular cases. We show that, for the memory-less deterministic tourist walk in the euclidean space, this distribution is Sinfinity(1,d) (t,p) = [Gamma (1+ I(-1)(d)) (t+ I(-1)(d) ) /Gamma(t+p+ I(-1)(d)) ] delta(p,2), where t=0, 1,2, ... infinity, Gamma(z) is the gamma function and delta(i,j) is the Kronecker delta. The mean-field models are the random link models, which correspond to d-->infinity, and the random map model which, even for mu=0 , presents nontrivial cycle distribution [ S(N)(0,rm) (p) proportional to p(-1) ] : S(N)(0,rm) (t,p) =Gamma(N)/ {Gamma[N+1- (t+p) ] N( t+p)}. The fundamental quantities are the number of explored points n(e)=t+p and Id. Although the obtained distributions are simple, they do not follow straightforwardly and they have been validated by numerical experiments.

Multiparty Quantum Direct Secret Sharing of Classical Information with Bell States and Bell Measurements

NASA Astrophysics Data System (ADS)

Song, Yun; Li, Yongming; Wang, Wenhua

2018-02-01

This paper proposed a new and efficient multiparty quantum direct secret sharing (QDSS) by using swapping quantum entanglement of Bell states. In the proposed scheme, the quantum correlation between the possible measurement results of the members (except dealer) and the original local unitary operation encoded by the dealer was presented. All agents only need to perform Bell measurements to share dealer's secret by recovering dealer's operation without performing any unitary operation. Our scheme has several advantages. The dealer is not required to retain any photons, and can further share a predetermined key instead of a random key to the agents. It has high capacity as two bits of secret messages can be transmitted by an EPR pair and the intrinsic efficiency approaches 100%, because no classical bit needs to be transmitted except those for detection. Without inserting any checking sets for detecting the eavesdropping, the scheme can resist not only the existing attacks, but also the cheating attack from the dishonest agent.

Quantum one-way permutation over the finite field of two elements

NASA Astrophysics Data System (ADS)

de Castro, Alexandre

2017-06-01

In quantum cryptography, a one-way permutation is a bounded unitary operator U:{H} → {H} on a Hilbert space {H} that is easy to compute on every input, but hard to invert given the image of a random input. Levin (Probl Inf Transm 39(1):92-103, 2003) has conjectured that the unitary transformation g(a,x)=(a,f(x)+ax), where f is any length-preserving function and a,x \\in {GF}_{{2}^{\\Vert x\\Vert }}, is an information-theoretically secure operator within a polynomial factor. Here, we show that Levin's one-way permutation is provably secure because its output values are four maximally entangled two-qubit states, and whose probability of factoring them approaches zero faster than the multiplicative inverse of any positive polynomial poly( x) over the Boolean ring of all subsets of x. Our results demonstrate through well-known theorems that existence of classical one-way functions implies existence of a universal quantum one-way permutation that cannot be inverted in subexponential time in the worst case.

Matrix elements and duality for type 2 unitary representations of the Lie superalgebra gl(m|n)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werry, Jason L.; Gould, Mark D.; Isaac, Phillip S.

The characteristic identity formalism discussed in our recent articles is further utilized to derive matrix elements of type 2 unitary irreducible gl(m|n) modules. In particular, we give matrix element formulae for all gl(m|n) generators, including the non-elementary generators, together with their phases on finite dimensional type 2 unitary irreducible representations which include the contravariant tensor representations and an additional class of essentially typical representations. Remarkably, we find that the type 2 unitary matrix element equations coincide with the type 1 unitary matrix element equations for non-vanishing matrix elements up to a phase.

Core shroud corner joints

DOEpatents

Gilmore, Charles B.; Forsyth, David R.

2013-09-10

A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

Unitary lens semiconductor device

DOEpatents

Lear, Kevin L.

1997-01-01

A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

Crossover between the Gaussian orthogonal ensemble, the Gaussian unitary ensemble, and Poissonian statistics.

PubMed

Schweiner, Frank; Laturner, Jeanine; Main, Jörg; Wunner, Günter

2017-11-01

Until now only for specific crossovers between Poissonian statistics (P), the statistics of a Gaussian orthogonal ensemble (GOE), or the statistics of a Gaussian unitary ensemble (GUE) have analytical formulas for the level spacing distribution function been derived within random matrix theory. We investigate arbitrary crossovers in the triangle between all three statistics. To this aim we propose an according formula for the level spacing distribution function depending on two parameters. Comparing the behavior of our formula for the special cases of P→GUE, P→GOE, and GOE→GUE with the results from random matrix theory, we prove that these crossovers are described reasonably. Recent investigations by F. Schweiner et al. [Phys. Rev. E 95, 062205 (2017)2470-004510.1103/PhysRevE.95.062205] have shown that the Hamiltonian of magnetoexcitons in cubic semiconductors can exhibit all three statistics in dependence on the system parameters. Evaluating the numerical results for magnetoexcitons in dependence on the excitation energy and on a parameter connected with the cubic valence band structure and comparing the results with the formula proposed allows us to distinguish between regular and chaotic behavior as well as between existent or broken antiunitary symmetries. Increasing one of the two parameters, transitions between different crossovers, e.g., from the P→GOE to the P→GUE crossover, are observed and discussed.

Cloud Quantum Computing of an Atomic Nucleus

NASA Astrophysics Data System (ADS)

Dumitrescu, E. F.; McCaskey, A. J.; Hagen, G.; Jansen, G. R.; Morris, T. D.; Papenbrock, T.; Pooser, R. C.; Dean, D. J.; Lougovski, P.

2018-05-01

We report a quantum simulation of the deuteron binding energy on quantum processors accessed via cloud servers. We use a Hamiltonian from pionless effective field theory at leading order. We design a low-depth version of the unitary coupled-cluster ansatz, use the variational quantum eigensolver algorithm, and compute the binding energy to within a few percent. Our work is the first step towards scalable nuclear structure computations on a quantum processor via the cloud, and it sheds light on how to map scientific computing applications onto nascent quantum devices.

Cloud Quantum Computing of an Atomic Nucleus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumitrescu, Eugene F.; McCaskey, Alex J.; Hagen, Gaute

Here, we report a quantum simulation of the deuteron binding energy on quantum processors accessed via cloud servers. We use a Hamiltonian from pionless effective field theory at leading order. We design a low-depth version of the unitary coupled-cluster ansatz, use the variational quantum eigensolver algorithm, and compute the binding energy to within a few percent. Our work is the first step towards scalable nuclear structure computations on a quantum processor via the cloud, and it sheds light on how to map scientific computing applications onto nascent quantum devices.

On the domain of the Nelson Hamiltonian

NASA Astrophysics Data System (ADS)

Griesemer, M.; Wünsch, A.

2018-04-01

The Nelson Hamiltonian is unitarily equivalent to a Hamiltonian defined through a closed, semibounded quadratic form, the unitary transformation being explicitly known and due to Gross. In this paper, we study the mapping properties of the Gross-transform in order to characterize the regularity properties of vectors in the form domain of the Nelson Hamiltonian. Since the operator domain is a subset of the form domain, our results apply to vectors in the domain of the Hamiltonian as well. This work is a continuation of our previous work on the Fröhlich Hamiltonian.

Quantum digital-to-analog conversion algorithm using decoherence

NASA Astrophysics Data System (ADS)

SaiToh, Akira

2015-08-01

We consider the problem of mapping digital data encoded on a quantum register to analog amplitudes in parallel. It is shown to be unlikely that a fully unitary polynomial-time quantum algorithm exists for this problem; NP becomes a subset of BQP if it exists. In the practical point of view, we propose a nonunitary linear-time algorithm using quantum decoherence. It tacitly uses an exponentially large physical resource, which is typically a huge number of identical molecules. Quantumness of correlation appearing in the process of the algorithm is also discussed.

Cloud Quantum Computing of an Atomic Nucleus.

PubMed

Dumitrescu, E F; McCaskey, A J; Hagen, G; Jansen, G R; Morris, T D; Papenbrock, T; Pooser, R C; Dean, D J; Lougovski, P

2018-05-25

We report a quantum simulation of the deuteron binding energy on quantum processors accessed via cloud servers. We use a Hamiltonian from pionless effective field theory at leading order. We design a low-depth version of the unitary coupled-cluster ansatz, use the variational quantum eigensolver algorithm, and compute the binding energy to within a few percent. Our work is the first step towards scalable nuclear structure computations on a quantum processor via the cloud, and it sheds light on how to map scientific computing applications onto nascent quantum devices.

Three-dimensional dualities with bosons and fermions

NASA Astrophysics Data System (ADS)

Benini, Francesco

2018-02-01

We propose new infinite families of non-supersymmetric IR dualities in three space-time dimensions, between Chern-Simons gauge theories (with classical gauge groups) with both scalars and fermions in the fundamental representation. In all cases we study the phase diagram as we vary two relevant couplings, finding interesting lines of phase transitions. In various cases the dualities lead to predictions about multi-critical fixed points and the emergence of IR quantum symmetries. For unitary groups we also discuss the coupling to background gauge fields and the map of simple monopole operators.

Cloud Quantum Computing of an Atomic Nucleus

DOE PAGES

Dumitrescu, Eugene F.; McCaskey, Alex J.; Hagen, Gaute; ...

2018-05-23

Here, we report a quantum simulation of the deuteron binding energy on quantum processors accessed via cloud servers. We use a Hamiltonian from pionless effective field theory at leading order. We design a low-depth version of the unitary coupled-cluster ansatz, use the variational quantum eigensolver algorithm, and compute the binding energy to within a few percent. Our work is the first step towards scalable nuclear structure computations on a quantum processor via the cloud, and it sheds light on how to map scientific computing applications onto nascent quantum devices.

Tunable arbitrary unitary transformer based on multiple sections of multicore fibers with phase control.

PubMed

Zhou, Junhe; Wu, Jianjie; Hu, Qinsong

2018-02-05

In this paper, we propose a novel tunable unitary transformer, which can achieve arbitrary discrete unitary transforms. The unitary transformer is composed of multiple sections of multi-core fibers with closely aligned coupled cores. Phase shifters are inserted before and after the sections to control the phases of the waves in the cores. A simple algorithm is proposed to find the optimal phase setup for the phase shifters to realize the desired unitary transforms. The proposed device is fiber based and is particularly suitable for the mode division multiplexing systems. A tunable mode MUX/DEMUX for a three-mode fiber is designed based on the proposed structure.

A unitary healing praxis model for women in despair.

PubMed

Cowling, W Richard

2006-04-01

The evolution of a unitary healing praxis model derived from three unitary appreciative inquiries of despair is described. Explication of unitary appreciative inquiry and how it informed and contributed to the development of the model is provided. The model is based on a conceptualization of healing as appreciating the inherent wholeness of life and provides knowledge specific to the individual lives of women in despair. The process of generative theorizing that led to the creation of the model is explicated. Unitary, appreciative, and participatory responses to despair are integrated in the model, praxis modalities are delineated, key concerns and perspectives of women in despair are addressed, and potentialities for healing are illustrated.

Instrument development and the measurement of unitary constructs.

PubMed

Carboni, J T

1992-01-01

This article initiates needed dialogue on the development of instruments to measure unitary constructs. The concept of measurement is explored and current measurement in Rogerian research is considered in light of the issues raised in the discussion. The human field - environmental field relationship is presented as the clinical practice area serving as the basis for the development of a unitary instrument that purports to measure field pattern. The instrument entitled Mutual Exploration of the Healing Human Field - Environmental Field Relationship is offered as a beginning effort in constructing an instrument that measures a unitary phenomenon. Rogerian scholars are provided with the challenge to continue the debate regarding the whole field of measurement and the development of unitary tools.

Unitary lens semiconductor device

DOEpatents

Lear, K.L.

1997-05-27

A unitary lens semiconductor device and method are disclosed. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors. 9 figs.

Repeatability of measurements: Non-Hermitian observables and quantum Coriolis force

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardas, Bartłomiej; Deffner, Sebastian; Saxena, Avadh

A noncommuting measurement transfers, via the apparatus, information encoded in a system's state to the external “observer.” Classical measurements determine properties of physical objects. In the quantum realm, the very same notion restricts the recording process to orthogonal states as only those are distinguishable by measurements. Thus, even a possibility to describe physical reality by means of non-Hermitian operators should volens nolens be excluded as their eigenstates are not orthogonal. We show that non-Hermitian operators with real spectra can be treated within the standard framework of quantum mechanics. Further, we propose a quantum canonical transformation that maps Hermitian systems ontomore » non-Hermitian ones. Similar to classical inertial forces this map is accompanied by an energetic cost, pinning the system on the unitary path.« less

Repeatability of measurements: Non-Hermitian observables and quantum Coriolis force

DOE PAGES

Gardas, Bartłomiej; Deffner, Sebastian; Saxena, Avadh

2016-08-26

A noncommuting measurement transfers, via the apparatus, information encoded in a system's state to the external “observer.” Classical measurements determine properties of physical objects. In the quantum realm, the very same notion restricts the recording process to orthogonal states as only those are distinguishable by measurements. Thus, even a possibility to describe physical reality by means of non-Hermitian operators should volens nolens be excluded as their eigenstates are not orthogonal. We show that non-Hermitian operators with real spectra can be treated within the standard framework of quantum mechanics. Further, we propose a quantum canonical transformation that maps Hermitian systems ontomore » non-Hermitian ones. Similar to classical inertial forces this map is accompanied by an energetic cost, pinning the system on the unitary path.« less

Asymptotic analysis of the density of states in random matrix models associated with a slowly decaying weight

NASA Astrophysics Data System (ADS)

Kuijlaars, A. B. J.

2001-08-01

The asymptotic behavior of polynomials that are orthogonal with respect to a slowly decaying weight is very different from the asymptotic behavior of polynomials that are orthogonal with respect to a Freud-type weight. While the latter has been extensively studied, much less is known about the former. Following an earlier investigation into the zero behavior, we study here the asymptotics of the density of states in a unitary ensemble of random matrices with a slowly decaying weight. This measure is also naturally connected with the orthogonal polynomials. It is shown that, after suitable rescaling, the weak limit is the same as the weak limit of the rescaled zeros.

Separability and Entanglement in the Hilbert Space Reference Frames Related Through the Generic Unitary Transform for Four Level System

NASA Astrophysics Data System (ADS)

Man'ko, V. I.; Markovich, L. A.

2018-02-01

Quantum correlations in the state of four-level atom are investigated by using generic unitary transforms of the classical (diagonal) density matrix. Partial cases of pure state, X-state, Werner state are studied in details. The geometrical meaning of unitary Hilbert reference-frame rotations generating entanglement in the initially separable state is discussed. Characteristics of the entanglement in terms of concurrence, entropy and negativity are obtained as functions of the unitary matrix rotating the reference frame.

Local unitary equivalence of quantum states and simultaneous orthogonal equivalence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jing, Naihuan, E-mail: jing@ncsu.edu; Yang, Min; Zhao, Hui, E-mail: zhaohui@bjut.edu.cn

2016-06-15

The correspondence between local unitary equivalence of bipartite quantum states and simultaneous orthogonal equivalence is thoroughly investigated and strengthened. It is proved that local unitary equivalence can be studied through simultaneous similarity under projective orthogonal transformations, and four parametrization independent algorithms are proposed to judge when two density matrices on ℂ{sup d{sub 1}} ⊗ ℂ{sup d{sub 2}} are locally unitary equivalent in connection with trace identities, Kronecker pencils, Albert determinants and Smith normal forms.

Entanglement quantification by local unitary operations

NASA Astrophysics Data System (ADS)

Monras, A.; Adesso, G.; Giampaolo, S. M.; Gualdi, G.; Davies, G. B.; Illuminati, F.

2011-07-01

Invariance under local unitary operations is a fundamental property that must be obeyed by every proper measure of quantum entanglement. However, this is not the only aspect of entanglement theory where local unitary operations play a relevant role. In the present work we show that the application of suitable local unitary operations defines a family of bipartite entanglement monotones, collectively referred to as “mirror entanglement.” They are constructed by first considering the (squared) Hilbert-Schmidt distance of the state from the set of states obtained by applying to it a given local unitary operator. To the action of each different local unitary operator there corresponds a different distance. We then minimize these distances over the sets of local unitary operations with different spectra, obtaining an entire family of different entanglement monotones. We show that these mirror-entanglement monotones are organized in a hierarchical structure, and we establish the conditions that need to be imposed on the spectrum of a local unitary operator for the associated mirror entanglement to be faithful, i.e., to vanish in and only in separable pure states. We analyze in detail the properties of one particularly relevant member of the family, the “stellar mirror entanglement” associated with the traceless local unitary operations with nondegenerate spectra and equispaced eigenvalues in the complex plane. This particular measure generalizes the original analysis of S. M. Giampaolo and F. Illuminati [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.76.042301 76, 042301 (2007)], valid for qubits and qutrits. We prove that the stellar entanglement is a faithful bipartite entanglement monotone in any dimension and that it is bounded from below by a function proportional to the linear entropy and from above by the linear entropy itself, coinciding with it in two- and three-dimensional spaces.

Entanglement quantification by local unitary operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monras, A.; Giampaolo, S. M.; Gualdi, G.

2011-07-15

Invariance under local unitary operations is a fundamental property that must be obeyed by every proper measure of quantum entanglement. However, this is not the only aspect of entanglement theory where local unitary operations play a relevant role. In the present work we show that the application of suitable local unitary operations defines a family of bipartite entanglement monotones, collectively referred to as ''mirror entanglement.'' They are constructed by first considering the (squared) Hilbert-Schmidt distance of the state from the set of states obtained by applying to it a given local unitary operator. To the action of each different localmore » unitary operator there corresponds a different distance. We then minimize these distances over the sets of local unitary operations with different spectra, obtaining an entire family of different entanglement monotones. We show that these mirror-entanglement monotones are organized in a hierarchical structure, and we establish the conditions that need to be imposed on the spectrum of a local unitary operator for the associated mirror entanglement to be faithful, i.e., to vanish in and only in separable pure states. We analyze in detail the properties of one particularly relevant member of the family, the ''stellar mirror entanglement'' associated with the traceless local unitary operations with nondegenerate spectra and equispaced eigenvalues in the complex plane. This particular measure generalizes the original analysis of S. M. Giampaolo and F. Illuminati [Phys. Rev. A 76, 042301 (2007)], valid for qubits and qutrits. We prove that the stellar entanglement is a faithful bipartite entanglement monotone in any dimension and that it is bounded from below by a function proportional to the linear entropy and from above by the linear entropy itself, coinciding with it in two- and three-dimensional spaces.« less

Generalized exact holographic mapping with wavelets

NASA Astrophysics Data System (ADS)

Lee, Ching Hua

2017-12-01

The idea of renormalization and scale invariance is pervasive across disciplines. It has not only drawn numerous surprising connections between physical systems under the guise of holographic duality, but has also inspired the development of wavelet theory now widely used in signal processing. Synergizing on these two developments, we describe in this paper a generalized exact holographic mapping that maps a generic N -dimensional lattice system to a (N +1 )-dimensional holographic dual, with the emergent dimension representing scale. In previous works, this was achieved via the iterations of the simplest of all unitary mappings, the Haar mapping, which fails to preserve the form of most Hamiltonians. By taking advantage of the full generality of biorthogonal wavelets, our new generalized holographic mapping framework is able to preserve the form of a large class of lattice Hamiltonians. By explicitly separating features that are fundamentally associated with the physical system from those that are basis specific, we also obtain a clearer understanding of how the resultant bulk geometry arises. For instance, the number of nonvanishing moments of the high-pass wavelet filter is revealed to be proportional to the radius of the dual anti-de Sitter space geometry. We conclude by proposing modifications to the mapping for systems with generic Fermi pockets.

Duality quantum algorithm efficiently simulates open quantum systems

PubMed Central

Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

2016-01-01

Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d3) in contrast to O(d4) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm. PMID:27464855

Threshold quantum state sharing based on entanglement swapping

NASA Astrophysics Data System (ADS)

Qin, Huawang; Tso, Raylin

2018-06-01

A threshold quantum state sharing scheme is proposed. The dealer uses the quantum-controlled-not operations to expand the d-dimensional quantum state and then uses the entanglement swapping to distribute the state to a random subset of participants. The participants use the single-particle measurements and unitary operations to recover the initial quantum state. In our scheme, the dealer can share different quantum states among different subsets of participants simultaneously. So the scheme will be very flexible in practice.

Spectral fluctuations of quantum graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pluhař, Z.; Weidenmüller, H. A.

We prove the Bohigas-Giannoni-Schmit conjecture in its most general form for completely connected simple graphs with incommensurate bond lengths. We show that for graphs that are classically mixing (i.e., graphs for which the spectrum of the classical Perron-Frobenius operator possesses a finite gap), the generating functions for all (P,Q) correlation functions for both closed and open graphs coincide (in the limit of infinite graph size) with the corresponding expressions of random-matrix theory, both for orthogonal and for unitary symmetry.

Operator Hydrodynamics, OTOCs, and Entanglement Growth in Systems without Conservation Laws

NASA Astrophysics Data System (ADS)

von Keyserlingk, C. W.; Rakovszky, Tibor; Pollmann, Frank; Sondhi, S. L.

2018-04-01

Thermalization and scrambling are the subject of much recent study from the perspective of many-body quantum systems with locally bounded Hilbert spaces ("spin chains"), quantum field theory, and holography. We tackle this problem in 1D spin chains evolving under random local unitary circuits and prove a number of exact results on the behavior of out-of-time-ordered commutators (OTOCs) and entanglement growth in this setting. These results follow from the observation that the spreading of operators in random circuits is described by a "hydrodynamical" equation of motion, despite the fact that random unitary circuits do not have locally conserved quantities (e.g., no conserved energy). In this hydrodynamic picture, quantum information travels in a front with a "butterfly velocity" vB that is smaller than the light-cone velocity of the system, while the front itself broadens diffusively in time. The OTOC increases sharply after the arrival of the light cone, but we do not observe a prolonged exponential regime of the form ˜eλL(t -x /v ) for a fixed Lyapunov exponent λL. We find that the diffusive broadening of the front has important consequences for entanglement growth, leading to an entanglement velocity that can be significantly smaller than the butterfly velocity. We conjecture that the hydrodynamical description applies to more generic Floquet ergodic systems, and we support this idea by verifying numerically that the diffusive broadening of the operator wavefront also holds in a more traditional nonrandom Floquet spin chain. We also compare our results to Clifford circuits, which have less rich hydrodynamics and consequently trivial OTOC behavior, but which can nevertheless exhibit linear entanglement growth and thermalization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guedes, Carlos; Oriti, Daniele; Raasakka, Matti

The phase space given by the cotangent bundle of a Lie group appears in the context of several models for physical systems. A representation for the quantum system in terms of non-commutative functions on the (dual) Lie algebra, and a generalized notion of (non-commutative) Fourier transform, different from standard harmonic analysis, has been recently developed, and found several applications, especially in the quantum gravity literature. We show that this algebra representation can be defined on the sole basis of a quantization map of the classical Poisson algebra, and identify the conditions for its existence. In particular, the corresponding non-commutative star-productmore » carried by this representation is obtained directly from the quantization map via deformation quantization. We then clarify under which conditions a unitary intertwiner between such algebra representation and the usual group representation can be constructed giving rise to the non-commutative plane waves and consequently, the non-commutative Fourier transform. The compact groups U(1) and SU(2) are considered for different choices of quantization maps, such as the symmetric and the Duflo map, and we exhibit the corresponding star-products, algebra representations, and non-commutative plane waves.« less

Spectral stability of unitary network models

NASA Astrophysics Data System (ADS)

Asch, Joachim; Bourget, Olivier; Joye, Alain

2015-08-01

We review various unitary network models used in quantum computing, spectral analysis or condensed matter physics and establish relationships between them. We show that symmetric one-dimensional quantum walks are universal, as are CMV matrices. We prove spectral stability and propagation properties for general asymptotically uniform models by means of unitary Mourre theory.

Completing the physical representation of quantum algorithms provides a retrocausal explanation of the speedup

NASA Astrophysics Data System (ADS)

Castagnoli, Giuseppe

2017-05-01

The usual representation of quantum algorithms, limited to the process of solving the problem, is physically incomplete as it lacks the initial measurement. We extend it to the process of setting the problem. An initial measurement selects a problem setting at random, and a unitary transformation sends it into the desired setting. The extended representation must be with respect to Bob, the problem setter, and any external observer. It cannot be with respect to Alice, the problem solver. It would tell her the problem setting and thus the solution of the problem implicit in it. In the representation to Alice, the projection of the quantum state due to the initial measurement should be postponed until the end of the quantum algorithm. In either representation, there is a unitary transformation between the initial and final measurement outcomes. As a consequence, the final measurement of any ℛ-th part of the solution could select back in time a corresponding part of the random outcome of the initial measurement; the associated projection of the quantum state should be advanced by the inverse of that unitary transformation. This, in the representation to Alice, would tell her, before she begins her problem solving action, that part of the solution. The quantum algorithm should be seen as a sum over classical histories in each of which Alice knows in advance one of the possible ℛ-th parts of the solution and performs the oracle queries still needed to find it - this for the value of ℛ that explains the algorithm's speedup. We have a relation between retrocausality ℛ and the number of oracle queries needed to solve an oracle problem quantumly. All the oracle problems examined can be solved with any value of ℛ up to an upper bound attained by the optimal quantum algorithm. This bound is always in the vicinity of 1/2 . Moreover, ℛ =1/2 always provides the order of magnitude of the number of queries needed to solve the problem in an optimal quantum way. If this were true for any oracle problem, as plausible, it would solve the quantum query complexity problem.

The prognostic value of formal thought disorder following first episode psychosis.

PubMed

Roche, Eric; Lyne, John; O'Donoghue, Brian; Segurado, Ricardo; Behan, Caragh; Renwick, Laoise; Fanning, Felicity; Madigan, Kevin; Clarke, Mary

2016-12-01

Formal thought disorder (FTD) is associated with poor outcome in established psychotic illnesses and it can be assessed as a categorical or dimensional variable. However, its influence on functional outcome and hospitalisation patterns in early psychosis has not been investigated. We evaluated the relationship between FTD and these outcomes in a first episode psychosis (FEP) sample. A mixed diagnostic FEP cohort was recruited through an Early Intervention in Psychosis Service in Ireland. Participants were assessed at initial presentation and one year later with the MIRECC GAF to evaluate social and occupational functioning domains. Disorganisation (disFTD), verbosity (verFTD) and poverty (povFTD) dimensions of FTD were examined at both time points, as well as a unitary FTD construct. Analyses were controlled for demographic, clinical and treatment variables. DisFTD was the only FTD dimension associated with functional outcome, specifically social functioning, on multivariate analysis (beta=0.13, P<0.05). The unitary FTD construct was not associated with functional outcome. DisFTD at FEP presentation predicted a greater number of hospitalisations (adjusted beta=0.24, P<0.001) and prolonged inpatient admission (adjusted OR=1.08, 95% CI 1.02-1.15, P<0.05) following FEP. Longitudinal and dimensional evaluation of FTD has a clinical utility that is distinct from a cross-sectional or unitary assessment. Dimensions of FTD may map onto different domains of functioning. These findings are supportive of some of the changes in DSM-V with an emphasis on longitudinal and dimensional appraisal of psychopathology. Communication disorders may be considered a potential target for intervention in psychotic disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

Integrability and nonintegrability of quantum systems. II. Dynamics in quantum phase space

NASA Astrophysics Data System (ADS)

Zhang, Wei-Min; Feng, Da Hsuan; Yuan, Jian-Min

1990-12-01

Based on the concepts of integrability and nonintegrability of a quantum system presented in a previous paper [Zhang, Feng, Yuan, and Wang, Phys. Rev. A 40, 438 (1989)], a realization of the dynamics in the quantum phase space is now presented. For a quantum system with dynamical group scrG and in one of its unitary irreducible-representation carrier spaces gerhΛ, the quantum phase space is a 2MΛ-dimensional topological space, where MΛ is the quantum-dynamical degrees of freedom. This quantum phase space is isomorphic to a coset space scrG/scrH via the unitary exponential mapping of the elementary excitation operator subspace of scrg (algebra of scrG), where scrH (⊂scrG) is the maximal stability subgroup of a fixed state in gerhΛ. The phase-space representation of the system is realized on scrG/scrH, and its classical analogy can be obtained naturally. It is also shown that there is consistency between quantum and classical integrability. Finally, a general algorithm for seeking the manifestation of ``quantum chaos'' via the classical analogy is provided. Illustrations of this formulation in several important quantum systems are presented.

Testing of the Trim Tab Parametric Model in NASA Langley's Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Murphy, Kelly J.; Watkins, Anthony N.; Korzun, Ashley M.; Edquist, Karl T.

2013-01-01

In support of NASA's Entry, Descent, and Landing technology development efforts, testing of Langley's Trim Tab Parametric Models was conducted in Test Section 2 of NASA Langley's Unitary Plan Wind Tunnel. The objectives of these tests were to generate quantitative aerodynamic data and qualitative surface pressure data for experimental and computational validation and aerodynamic database development. Six component force-and-moment data were measured on 38 unique, blunt body trim tab configurations at Mach numbers of 2.5, 3.5, and 4.5, angles of attack from -4deg to +20deg, and angles of sideslip from 0deg to +8deg. Configuration parameters investigated in this study were forebody shape, tab area, tab cant angle, and tab aspect ratio. Pressure Sensitive Paint was used to provide qualitative surface pressure mapping for a subset of these flow and configuration variables. Over the range of parameters tested, the effects of varying tab area and tab cant angle were found to be much more significant than varying tab aspect ratio relative to key aerodynamic performance requirements. Qualitative surface pressure data supported the integrated aerodynamic data and provided information to aid in future analyses of localized phenomena for trim tab configurations.

Closed, analytic, boson realizations for Sp(4)

NASA Astrophysics Data System (ADS)

Klein, Abraham; Zhang, Qing-Ying

1986-08-01

The problem of determing a boson realization for an arbitrary irrep of the unitary simplectic algebra Sp(2d) [or of the corresponding discrete unitary irreps of the unbounded algebra Sp(2d,R)] has been solved completely in recent papers by Deenen and Quesne [J. Deenen and C. Quesne, J. Math. Phys. 23, 878, 2004 (1982); 25, 1638 (1984); 26, 2705 (1985)] and by Moshinsky and co-workers [O. Castaños, E. Chacón, M. Moshinsky, and C. Quesne, J. Math. Phys. 26, 2107 (1985); M. Moshinsky, ``Boson realization of symplectic algebras,'' to be published]. This solution is not known in closed analytic form except for d=1 and for special classes of irreps for d>1. A different method of obtaining a boson realization that solves the full problem for Sp(4) is described. The method utilizes the chain Sp(2d)⊇SU(2)×SU(2) ×ṡṡṡ×SU(2) (d times), which, for d≥4, does not provide a complete set of quantum numbers. Though a simple solution of the missing label problem can be given, this solution does not help in the construction of a mapping algorithm for general d.

Role of the N*(1535) in the J/{psi}{yields}p{eta}p and J/{psi}{yields}pK{sup +}{lambda} reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, L. S.; Oset, E.; Zou, B. S.

2009-02-15

We study the J/{psi}{yields}p{eta}p and J/{psi}{yields}pK{sup +}{lambda} reactions with a unitary chiral approach. We find that the unitary chiral approach, which generates the N*(1535) dynamically, can describe the data reasonably well, particularly the ratio of the integrated cross sections. This study provides further support for the unitary chiral description of the N*(1535). We also discuss some subtle differences between the coupling constants determined from the unitary chiral approach and those determined from phenomenological studies.

Twisted Burnside-Frobenius Theory for Endomorphisms of Polycyclic Groups

NASA Astrophysics Data System (ADS)

Fel'shtyn, A. L.; Troitsky, E. V.

2018-01-01

Let R(ϕ) be the number of ϕ-conjugacy (or Reidemeister) classes of an endomorphism ϕ of a group G. We prove, for several classes of groups (including polycyclic ones), that the number R(ϕ) is equal to the number of fixed points of the induced mapping on an appropriate subspace of the unitary dual space Ĝ, when R(ϕ) < ∞. Applying the result to iterations of ϕ, we obtain Gauss congruences for Reidemeister numbers. In contrast to the case of automorphisms, studied previously, there are plenty examples having the above finiteness condition, even among groups with R ∞ property.

Unitary or Non-Unitary Nature of Working Memory? Evidence from Its Relation to General Fluid and Crystallized Intelligence

ERIC Educational Resources Information Center

Dang, Cai-Ping; Braeken, Johan; Ferrer, Emilio; Liu, Chang

2012-01-01

This study explored the controversy surrounding working memory: whether it is a unitary system providing general purpose resources or a more differentiated system with domain-specific sub-components. A total of 348 participants completed a set of 6 working memory tasks that systematically varied in storage target contents and type of information…

Efficient Nonlocal M-Control and N-Target Controlled Unitary Gate Using Non-symmetric GHZ States

NASA Astrophysics Data System (ADS)

Chen, Li-Bing; Lu, Hong

2018-03-01

Efficient local implementation of a nonlocal M-control and N-target controlled unitary gate is considered. We first show that with the assistance of two non-symmetric qubit(1)-qutrit(N) Greenberger-Horne-Zeilinger (GHZ) states, a nonlocal 2-control and N-target controlled unitary gate can be constructed from 2 local two-qubit CNOT gates, 2 N local two-qutrit conditional SWAP gates, N local qutrit-qubit controlled unitary gates, and 2 N single-qutrit gates. At each target node, the two third levels of the two GHZ target qutrits are used to expose one and only one initial computational state to the local qutrit-qubit controlled unitary gate, instead of being used to hide certain states from the conditional dynamics. This scheme can be generalized straightforwardly to implement a higher-order nonlocal M-control and N-target controlled unitary gate by using M non-symmetric qubit(1)-qutrit(N) GHZ states as quantum channels. Neither the number of the additional levels of each GHZ target particle nor that of single-qutrit gates needs to increase with M. For certain realistic physical systems, the total gate time may be reduced compared with that required in previous schemes.

Probing non-unitary CP violation effects in neutrino oscillation experiments

NASA Astrophysics Data System (ADS)

Verma, Surender; Bhardwaj, Shankita

2018-05-01

In the present work, we have considered minimal unitarity violation scheme to obtain the general expression for ν _{μ }→ ν _{τ } oscillation probability in vacuum and matter. For this channel, we have investigated the sensitivities of short baseline experiments to non-unitary parameters |ρ _{μ τ }| and ω _{μ τ } for normal as well as inverted hierarchical neutrino masses and θ _{23} being above or below maximality. We find that for normal hierarchy, the 3σ sensitivity of |ρ _{μ τ }| is maximum for non-unitary phase ω _{μ τ }=0 whereas it is minimum for ω _{μ τ }=± π . For inverted hierarchy, the sensitivity is minimum at ω _{μ τ }=0 and maximum for ω _{μ τ }=± π . We observe that the sensitivity to measure non-unitarity remains unaffected for unitary CP phase δ =0 or δ =π /2 . We have, also, explored wide spectrum of L/E ratio to investigate the possibilities to observe CP-violation due to unitary (δ ) and non-unitary (ω _{μ τ } ) phases. We find that the both phases can be disentangled, in principle, from each other for L/E<200 km/GeV.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashi, A.; Hashimoto, T.; Horibe, M.

The quantum color coding scheme proposed by Korff and Kempe [e-print quant-ph/0405086] is easily extended so that the color coding quantum system is allowed to be entangled with an extra auxiliary quantum system. It is shown that in the extended scheme we need only {approx}2{radical}(N) quantum colors to order N objects in large N limit, whereas {approx}N/e quantum colors are required in the original nonextended version. The maximum success probability has asymptotics expressed by the Tracy-Widom distribution of the largest eigenvalue of a random Gaussian unitary ensemble (GUE) matrix.

Patterning of pain and power with guided imagery.

PubMed

Lewandowski, Wendy A

2004-07-01

Using Martha Rogers' science of unitary human beings, changes in pain and power among 42 patients were examined in relation to the use of a guided imagery modality. Participants were randomly assigned to treatment and control groups and repeated measures MANCOVA was used to detect differences in pain and power over a 4-day period of time. The treatment group's pain decreased during the last 2 days of the study. No differences in power emerged. Guided imagery appeared to have potential as a useful nursing modality for chronic pain sufferers.

SU(p,q) coherent states and a Gaussian de Finetti theorem

NASA Astrophysics Data System (ADS)

Leverrier, Anthony

2018-04-01

We prove a generalization of the quantum de Finetti theorem when the local space is an infinite-dimensional Fock space. In particular, instead of considering the action of the permutation group on n copies of that space, we consider the action of the unitary group U(n) on the creation operators of the n modes and define a natural generalization of the symmetric subspace as the space of states invariant under unitaries in U(n). Our first result is a complete characterization of this subspace, which turns out to be spanned by a family of generalized coherent states related to the special unitary group SU(p, q) of signature (p, q). More precisely, this construction yields a unitary representation of the noncompact simple real Lie group SU(p, q). We therefore find a dual unitary representation of the pair of groups U(n) and SU(p, q) on an n(p + q)-mode Fock space. The (Gaussian) SU(p, q) coherent states resolve the identity on the symmetric subspace, which implies a Gaussian de Finetti theorem stating that tracing over a few modes of a unitary-invariant state yields a state close to a mixture of Gaussian states. As an application of this de Finetti theorem, we show that the n × n upper-left submatrix of an n × n Haar-invariant unitary matrix is close in total variation distance to a matrix of independent normal variables if n3 = O(m).

Implementation of bipartite or remote unitary gates with repeater nodes

NASA Astrophysics Data System (ADS)

Yu, Li; Nemoto, Kae

2016-08-01

We propose some protocols to implement various classes of bipartite unitary operations on two remote parties with the help of repeater nodes in-between. We also present a protocol to implement a single-qubit unitary with parameters determined by a remote party with the help of up to three repeater nodes. It is assumed that the neighboring nodes are connected by noisy photonic channels, and the local gates can be performed quite accurately, while the decoherence of memories is significant. A unitary is often a part of a larger computation or communication task in a quantum network, and to reduce the amount of decoherence in other systems of the network, we focus on the goal of saving the total time for implementing a unitary including the time for entanglement preparation. We review some previously studied protocols that implement bipartite unitaries using local operations and classical communication and prior shared entanglement, and apply them to the situation with repeater nodes without prior entanglement. We find that the protocols using piecewise entanglement between neighboring nodes often require less total time compared to preparing entanglement between the two end nodes first and then performing the previously known protocols. For a generic bipartite unitary, as the number of repeater nodes increases, the total time could approach the time cost for direct signal transfer from one end node to the other. We also prove some lower bounds of the total time when there are a small number of repeater nodes. The application to position-based cryptography is discussed.

Quantum mechanics on periodic and non-periodic lattices and almost unitary Schwinger operators

NASA Astrophysics Data System (ADS)

Arik, Metin; Ildes, Medine

2018-05-01

In this work, we uncover the mathematical structure of the Schwinger algebra and introduce almost unitary Schwinger operators which are derived by considering translation operators on a finite lattice. We calculate mathematical relations between these algebras and show that the almost unitary Schwinger operators are equivalent to the Schwinger algebra. We introduce new representations for MN(C) in terms of these algebras.

Representation of natural numbers in quantum mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benioff, Paul

2001-03-01

This paper represents one approach to making explicit some of the assumptions and conditions implied in the widespread representation of numbers by composite quantum systems. Any nonempty set and associated operations is a set of natural numbers or a model of arithmetic if the set and operations satisfy the axioms of number theory or arithmetic. This paper is limited to k-ary representations of length L and to the axioms for arithmetic modulo k{sup L}. A model of the axioms is described based on an abstract L-fold tensor product Hilbert space H{sup arith}. Unitary maps of this space onto a physicalmore » parameter based product space H{sup phy} are then described. Each of these maps makes states in H{sup phy}, and the induced operators, a model of the axioms. Consequences of the existence of many of these maps are discussed along with the dependence of Grover's and Shor's algorithms on these maps. The importance of the main physical requirement, that the basic arithmetic operations are efficiently implementable, is discussed. This condition states that there exist physically realizable Hamiltonians that can implement the basic arithmetic operations and that the space-time and thermodynamic resources required are polynomial in L.« less

Natural resource theory of unitary taxation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, J.L.; Reynolds, A.

1985-01-01

Empirical evidence supports the tentative hypothesis that unitary taxation encourages natural resource recovery in states well endowed with timber, fuels, and nonfuel minerals. Consequently, if combined apportionment is a stable institution in any state, it will remain so while extractive industries, with higher upstream than downstream profitability, continue to dominate the state's economy. Over time, however, nonproducing states will abandon unitary taxation to prevent integrated firms from disinvesting within their borders and expanding operations in states with a hospitable investment climate. Since states, like firms, must compete with one another, unitary taxation will become less important as state economies becomemore » less dependent on the recovery of natural resources. 43 references, 1 figure, 4 tables.« less

Universal shocks in the Wishart random-matrix ensemble.

PubMed

Blaizot, Jean-Paul; Nowak, Maciej A; Warchoł, Piotr

2013-05-01

We show that the derivative of the logarithm of the average characteristic polynomial of a diffusing Wishart matrix obeys an exact partial differential equation valid for an arbitrary value of N, the size of the matrix. In the large N limit, this equation generalizes the simple inviscid Burgers equation that has been obtained earlier for Hermitian or unitary matrices. The solution, through the method of characteristics, presents singularities that we relate to the precursors of shock formation in the Burgers equation. The finite N effects appear as a viscosity term in the Burgers equation. Using a scaling analysis of the complete equation for the characteristic polynomial, in the vicinity of the shocks, we recover in a simple way the universal Bessel oscillations (so-called hard-edge singularities) familiar in random-matrix theory.

Robust Tomography using Randomized Benchmarking

NASA Astrophysics Data System (ADS)

Silva, Marcus; Kimmel, Shelby; Johnson, Blake; Ryan, Colm; Ohki, Thomas

2013-03-01

Conventional randomized benchmarking (RB) can be used to estimate the fidelity of Clifford operations in a manner that is robust against preparation and measurement errors -- thus allowing for a more accurate and relevant characterization of the average error in Clifford gates compared to standard tomography protocols. Interleaved RB (IRB) extends this result to the extraction of error rates for individual Clifford gates. In this talk we will show how to combine multiple IRB experiments to extract all information about the unital part of any trace preserving quantum process. Consequently, one can compute the average fidelity to any unitary, not just the Clifford group, with tighter bounds than IRB. Moreover, the additional information can be used to design improvements in control. MS, BJ, CR and TO acknowledge support from IARPA under contract W911NF-10-1-0324.

Unitary reconstruction of secret for stabilizer-based quantum secret sharing

NASA Astrophysics Data System (ADS)

Matsumoto, Ryutaroh

2017-08-01

We propose a unitary procedure to reconstruct quantum secret for a quantum secret sharing scheme constructed from stabilizer quantum error-correcting codes. Erasure correcting procedures for stabilizer codes need to add missing shares for reconstruction of quantum secret, while unitary reconstruction procedures for certain class of quantum secret sharing are known to work without adding missing shares. The proposed procedure also works without adding missing shares.

Minimal unitary representation of SO∗(8)=SO(6,2) and its SU(2) deformations as massless 6D conformal fields and their supersymmetric extensions

NASA Astrophysics Data System (ADS)

Fernando, Sudarshan; Günaydin, Murat

2010-12-01

We study the minimal unitary representation (minrep) of SO(6,2) over an Hilbert space of functions of five variables, obtained by quantizing its quasiconformal realization. The minrep of SO(6,2), which coincides with the minrep of SO(8) similarly constructed, corresponds to a massless conformal scalar field in six spacetime dimensions. There exists a family of "deformations" of the minrep of SO(8) labeled by the spin t of an SU(2 subgroup of the little group SO(4) of lightlike vectors. These deformations labeled by t are positive energy unitary irreducible representations of SO(8) that describe massless conformal fields in six dimensions. The SU(2 spin t is the six-dimensional counterpart of U(1) deformations of the minrep of 4D conformal group SU(2,2) labeled by helicity. We also construct the supersymmetric extensions of the minimal unitary representation of SO(8) to minimal unitary representations of OSp(8|2N) that describe massless six-dimensional conformal supermultiplets. The minimal unitary supermultiplet of OSp(8|4) is the massless supermultiplet of (2,0) conformal field theory that is believed to be dual to M-theory on AdS×S.

A Fock space representation for the quantum Lorentz gas

NASA Astrophysics Data System (ADS)

Maassen, H.; Tip, A.

1995-02-01

A Fock space representation is given for the quantum Lorentz gas, i.e., for random Schrödinger operators of the form H(ω)=p2+Vω=p2+∑ φ(x-xj(ω)), acting in H=L2(Rd), with Poisson distributed xjs. An operator H is defined in K=H⊗P=H⊗L2(Ω,P(dω))=L2(Ω,P(dω);H) by the action of H(ω) on its fibers in a direct integral decomposition. The stationarity of the Poisson process allows a unitarily equivalent description in terms of a new family {H(k)||k∈Rd}, where each H(k) acts in P [A. Tip, J. Math. Phys. 35, 113 (1994)]. The space P is then unitarily mapped upon the symmetric Fock space over L2(Rd,ρdx), with ρ the intensity of the Poisson process (the average number of points xj per unit volume; the scatterer density), and the equivalent of H(k) is determined. Averages now become vacuum expectation values and a further unitary transformation (removing ρ in ρdx) is made which leaves the former invariant. The resulting operator HF(k) has an interesting structure: On the nth Fock layer we encounter a single particle moving in the field of n scatterers and the randomness now appears in the coefficient √ρ in a coupling term connecting neighboring Fock layers. We also give a simple direct self-adjointness proof for HF(k), based upon Nelson's commutator theorem. Restriction to a finite number of layers (a kind of low scatterer density approximation) still gives nontrivial results, as is demonstrated by considering an example.

Identification and analysis of unitary pseudogenes: historic and contemporary gene losses in humans and other primates

PubMed Central

2010-01-01

Background Unitary pseudogenes are a class of unprocessed pseudogenes without functioning counterparts in the genome. They constitute only a small fraction of annotated pseudogenes in the human genome. However, as they represent distinct functional losses over time, they shed light on the unique features of humans in primate evolution. Results We have developed a pipeline to detect human unitary pseudogenes through analyzing the global inventory of orthologs between the human genome and its mammalian relatives. We focus on gene losses along the human lineage after the divergence from rodents about 75 million years ago. In total, we identify 76 unitary pseudogenes, including previously annotated ones, and many novel ones. By comparing each of these to its functioning ortholog in other mammals, we can approximately date the creation of each unitary pseudogene (that is, the gene 'death date') and show that for our group of 76, the functional genes appear to be disabled at a fairly uniform rate throughout primate evolution - not all at once, correlated, for instance, with the 'Alu burst'. Furthermore, we identify 11 unitary pseudogenes that are polymorphic - that is, they have both nonfunctional and functional alleles currently segregating in the human population. Comparing them with their orthologs in other primates, we find that two of them are in fact pseudogenes in non-human primates, suggesting that they represent cases of a gene being resurrected in the human lineage. Conclusions This analysis of unitary pseudogenes provides insights into the evolutionary constraints faced by different organisms and the timescales of functional gene loss in humans. PMID:20210993

Distribution of Schmidt-like eigenvalues for Gaussian ensembles of the random matrix theory

NASA Astrophysics Data System (ADS)

Pato, Mauricio P.; Oshanin, Gleb

2013-03-01

We study the probability distribution function P(β)n(w) of the Schmidt-like random variable w = x21/(∑j = 1nx2j/n), where xj, (j = 1, 2, …, n), are unordered eigenvalues of a given n × n β-Gaussian random matrix, β being the Dyson symmetry index. This variable, by definition, can be considered as a measure of how any individual (randomly chosen) eigenvalue deviates from the arithmetic mean value of all eigenvalues of a given random matrix, and its distribution is calculated with respect to the ensemble of such β-Gaussian random matrices. We show that in the asymptotic limit n → ∞ and for arbitrary β the distribution P(β)n(w) converges to the Marčenko-Pastur form, i.e. is defined as P_{n}^{( \\beta )}(w) \\sim \\sqrt{(4 - w)/w} for w ∈ [0, 4] and equals zero outside of the support, despite the fact that formally w is defined on the interval [0, n]. Furthermore, for Gaussian unitary ensembles (β = 2) we present exact explicit expressions for P(β = 2)n(w) which are valid for arbitrary n and analyse their behaviour.

Supersonic Retropropulsion Experimental Results from the NASA Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Berry, Scott A.; Rhode, Matthew N.; Edquist, Karl T.; Player, Charles J.

2011-01-01

A new supersonic retropropulsion experimental effort, intended to provide code validation data, was recently completed in the Langley Research Center Unitary Plan Wind Tunnel Test Section 2 over the Mach number range from 2.4 to 4.6. The experimental model was designed using insights gained from pre-test computations, which were instrumental for sizing and refining the model to minimize tunnel wall interference and internal flow separation concerns. A 5-in diameter 70-deg sphere-cone forebody with a roughly 10-in long cylindrical aftbody was the baseline configuration selected for this study. The forebody was designed to accommodate up to four 4:1 area ratio supersonic nozzles. Primary measurements for this model were a large number of surface pressures on the forebody and aftbody. Supplemental data included high-speed Schlieren video and internal pressures and temperatures. The run matrix was developed to allow for the quantification of various sources of experimental uncertainty, such as random errors due to run-to-run variations and bias errors due to flow field or model misalignments. Preliminary results and observations from the test are presented, while detailed data and uncertainty analyses are ongoing.

Noise of a Chargeless Fermi Liquid

NASA Astrophysics Data System (ADS)

Moca, Cǎtǎlin Paşcu; Mora, Christophe; Weymann, Ireneusz; Zaránd, Gergely

2018-01-01

We construct a Fermi liquid theory to describe transport in a superconductor-quantum dot-normal metal junction close to the singlet-doublet (parity changing) transition of the dot. Though quasiparticles do not have a definite charge in this chargeless Fermi liquid, in the case of particle-hole symmetry, a mapping to the Anderson model unveils a hidden U(1) symmetry and a corresponding pseudocharge. In contrast to other correlated Fermi liquids, the back scattering noise reveals an effective charge equal to the charge of Cooper pairs, e*=2 e . In addition, we find a strong suppression of noise when the linear conductance is unitary, even for its nonlinear part.

Alternative working fluids for unitary equipment: A research perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baxter, V.D.

This paper deals with present and planned ORNL activities to characterize alternatives to R-22 for unitary heat pump and air-conditioning applications. Results of small-scale bread-board tests of potential alternatives R-32, R-134a, R-152a and R-143a are discussed. Portions of the AFEAS/DOE global warming impact study dealing with the unitary application are summarized. Methods for leak detection with the new refrigerants are discussed.

Unidirectional Quantum Remote Control: Teleportation of Control-State

NASA Astrophysics Data System (ADS)

Zheng, Yi-Zhuang; Gu, Yong-Jian; Wu, Gui-Chu; Guo, Guang-Can

2003-08-01

We investigate the problem of teleportation of unitary operations by unidirectional control-state teleportation and propose a scheme called unidirectional quantum remote control. The scheme is based on the isomorphism between operation and state. It allows us to store a unitary operation in a control state, thereby teleportation of the unitary operation can be implemented by unidirectional teleportation of the control-state. We find that the probability of success for implementing an arbitrary unitary operation on arbitrary M-qubit state by unidirectional control-state teleportation is 4-M, and 2M ebits and 4M cbits are consumed in each teleportation. The project supported by the National Fundamental Research Programme (2001CB309300) and the Zhejiang Provincial Natural Science Foundation of China under Grant No. 102068

Non-unitary probabilistic quantum computing

NASA Technical Reports Server (NTRS)

Gingrich, Robert M.; Williams, Colin P.

2004-01-01

We present a method for designing quantum circuits that perform non-unitary quantum computations on n-qubit states probabilistically, and give analytic expressions for the success probability and fidelity.

Slaves immersed in a liberal ideology.

PubMed

Daly, Leslie Kim

2012-01-01

Paradigm debates have been featured in the nursing literature for over four decades. There are at least two opposing paradigms specific to nursing that have remained central in these debates. Advocates of the unitary perspective (or simultaneity paradigm) consider their theories to be more philosophically advanced and contemporary alternatives when compared to the older more traditional ideas characteristic of models they describe as originating from the totality paradigm. In the context of these debates, I focus on some theoretical positions embedded in the unitary perspective, noting their limitations with respect to integrating the individual and social mandates of nursing; nurses are responsible not only for individual health-related needs, but also for the health of the collective. I explore two hypotheses that may explain the powers of endurance of the unitary perspective. Paley, who outlines the origins of nurses' 'slave morality', inspires the first hypothesis. The second hypothesis speaks to the location of nursing knowledge development in the context of liberal ideology. In this work, I outline key conceptualizations of the unitary perspective in order to clearly illustrate the limitations of the unitary perspective for nurses' social mandate. Then, I explore how slave morality and liberal ideological assumptions might both work to sustain the unitary perspective. A paradigm for nursing must have utility in addressing both the health-related needs of individuals, and for addressing the health of the collective. To this end, I advance suggestions in three areas: first, to transform nurses' slave morality to more honest and noble aspirations; second, to examine liberal ideological premises; and third, to end paradigm debate by resituating elements of the unitary perspective to the level of mid-range theory, where it could be most effective for research and practice with specific populations. © 2011 Blackwell Publishing Ltd.

Caring science and the science of unitary human beings: a trans-theoretical discourse for nursing knowledge development.

PubMed

Watson, Jean; Smith, Marlaine C

2002-03-01

Two dominant discourses in contemporary nursing theory and knowledge development have evolved over the past few decades, in part by unitary science views and caring theories. Rogers' science of unitary human beings (SUHB) represents the unitary directions in nursing. Caring theories and related caring science (CS) scholarship represent the other. These two contemporary initiatives have generated two parallel, often controversial, seemingly separate and unrelated, trees of knowledge for nursing science. This paper explores the evolution of CS and its intersection with SUHB that have emerged in contemporary nursing literature. We present a case for integration, convergence, and creative synthesis of CS with SUHB. A trans-theoretical, trans-disciplinary context emerges, allowing nursing to sustain its caring ethic and ontology, within a unitary science. The authors critique and review the seminal, critical issues that have separated contemporary knowledge developments in CS and SUHB. Foundational issues of CS, and Watson's theory of transpersonal caring science (TCS), as a specific exemplar, are analysed, alongside parallel themes in SUHB. By examining hidden ethical-ontological and paradigmatic commonalities, trans-theoretical themes and connections are explored and revealed between TCS and SUHB. Through a creative synthesis of TCS and SUHB we explicate a distinct unitary view of human with a relational caring ontology and ethic that informs nursing as well as other sciences. The result: is a trans-theoretical, trans-disciplinary view for nursing knowledge development. Nursing's history has been to examine theoretical differences rather than commonalities. This trans-theoretical position moves nursing toward theoretical integration and creative synthesis, vs. separation, away from the 'Balkanization' of different theories. This initiative still maintains the integrity of different theories, while facilitating and inviting a new discourse for nursing science. The result: Unitary Caring Science that evokes both science and spirit.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deffner, Sebastian; Zurek, Wojciech H.

Envariance—entanglement assisted invariance—is a recently discovered symmetry of composite quantum systems. Here, we show that thermodynamic equilibrium states are fully characterized by their envariance. In particular, the microcanonical equilibrium of a systemmore » $${ \\mathcal S }$$ with Hamiltonian $${H}_{{ \\mathcal S }}$$ is a fully energetically degenerate quantum state envariant under every unitary transformation. A representation of the canonical equilibrium then follows from simply counting degenerate energy states. Finally, our conceptually novel approach is free of mathematically ambiguous notions such as ensemble, randomness, etc., and, while it does not even rely on probability, it helps to understand its role in the quantum world.« less

Quantum Entanglement in Random Physical States

NASA Astrophysics Data System (ADS)

Hamma, Alioscia; Santra, Siddhartha; Zanardi, Paolo

2012-07-01

Most states in the Hilbert space are maximally entangled. This fact has proven useful to investigate—among other things—the foundations of statistical mechanics. Unfortunately, most states in the Hilbert space of a quantum many-body system are not physically accessible. We define physical ensembles of states acting on random factorized states by a circuit of length k of random and independent unitaries with local support. We study the typicality of entanglement by means of the purity of the reduced state. We find that for a time k=O(1), the typical purity obeys the area law. Thus, the upper bounds for area law are actually saturated, on average, with a variance that goes to zero for large systems. Similarly, we prove that by means of local evolution a subsystem of linear dimensions L is typically entangled with a volume law when the time scales with the size of the subsystem. Moreover, we show that for large values of k the reduced state becomes very close to the completely mixed state.

Distribution law of the Dirac eigenmodes in QCD

NASA Astrophysics Data System (ADS)

Catillo, Marco; Glozman, Leonid Ya.

2018-04-01

The near-zero modes of the Dirac operator are connected to spontaneous breaking of chiral symmetry in QCD (SBCS) via the Banks-Casher relation. At the same time, the distribution of the near-zero modes is well described by the Random Matrix Theory (RMT) with the Gaussian Unitary Ensemble (GUE). Then, it has become a standard lore that a randomness, as observed through distributions of the near-zero modes of the Dirac operator, is a consequence of SBCS. The higher-lying modes of the Dirac operator are not affected by SBCS and are sensitive to confinement physics and related SU(2)CS and SU(2NF) symmetries. We study the distribution of the near-zero and higher-lying eigenmodes of the overlap Dirac operator within NF = 2 dynamical simulations. We find that both the distributions of the near-zero and higher-lying modes are perfectly described by GUE of RMT. This means that randomness, while consistent with SBCS, is not a consequence of SBCS and is linked to the confining chromo-electric field.

Buses of Cuernavaca—an agent-based model for universal random matrix behavior minimizing mutual information

NASA Astrophysics Data System (ADS)

Warchoł, Piotr

2018-06-01

The public transportation system of Cuernavaca, Mexico, exhibits random matrix theory statistics. In particular, the fluctuation of times between the arrival of buses on a given bus stop, follows the Wigner surmise for the Gaussian unitary ensemble. To model this, we propose an agent-based approach in which each bus driver tries to optimize his arrival time to the next stop with respect to an estimated arrival time of his predecessor. We choose a particular form of the associated utility function and recover the appropriate distribution in numerical experiments for a certain value of the only parameter of the model. We then investigate whether this value of the parameter is otherwise distinguished within an information theoretic approach and give numerical evidence that indeed it is associated with a minimum of averaged pairwise mutual information.

Individual eigenvalue distributions of crossover chiral random matrices and low-energy constants of SU(2) × U(1) lattice gauge theory

NASA Astrophysics Data System (ADS)

Yamamoto, Takuya; Nishigaki, Shinsuke M.

2018-02-01

We compute individual distributions of low-lying eigenvalues of a chiral random matrix ensemble interpolating symplectic and unitary symmetry classes by the Nyström-type method of evaluating the Fredholm Pfaffian and resolvents of the quaternion kernel. The one-parameter family of these distributions is shown to fit excellently the Dirac spectra of SU(2) lattice gauge theory with a constant U(1) background or dynamically fluctuating U(1) gauge field, which weakly breaks the pseudoreality of the unperturbed SU(2) Dirac operator. The observed linear dependence of the crossover parameter with the strength of the U(1) perturbations leads to precise determination of the pseudo-scalar decay constant, as well as the chiral condensate in the effective chiral Lagrangian of the AI class.

Optimal Synthesis of the Joint Unitary Evolutions

NASA Astrophysics Data System (ADS)

Wei, Hai-Rui; Alsaedi, Ahmed; Hobiny, Aatef; Deng, Fu-Guo; Hu, Hui; Zhang, Dun

2018-07-01

Joint unitary operations play a central role in quantum communication and computation. We give a quantum circuit for implementing a type of unconstructed useful joint unitary evolutions in terms of controlled-NOT (CNOT) gates and single-qubit rotations. Our synthesis is optimal and possible in experiment. Two CNOT gates and seven R x , R y or R z rotations are required for our synthesis, and the arbitrary parameter contained in the evolutions can be controlled by local Hamiltonian or external fields.

Optimal Synthesis of the Joint Unitary Evolutions

NASA Astrophysics Data System (ADS)

Wei, Hai-Rui; Alsaedi, Ahmed; Hobiny, Aatef; Deng, Fu-Guo; Hu, Hui; Zhang, Dun

2018-03-01

Joint unitary operations play a central role in quantum communication and computation. We give a quantum circuit for implementing a type of unconstructed useful joint unitary evolutions in terms of controlled-NOT (CNOT) gates and single-qubit rotations. Our synthesis is optimal and possible in experiment. Two CNOT gates and seven R x , R y or R z rotations are required for our synthesis, and the arbitrary parameter contained in the evolutions can be controlled by local Hamiltonian or external fields.

Designing quantum information processing via structural physical approximation.

PubMed

Bae, Joonwoo

2017-10-01

In quantum information processing it may be possible to have efficient computation and secure communication beyond the limitations of classical systems. In a fundamental point of view, however, evolution of quantum systems by the laws of quantum mechanics is more restrictive than classical systems, identified to a specific form of dynamics, that is, unitary transformations and, consequently, positive and completely positive maps to subsystems. This also characterizes classes of disallowed transformations on quantum systems, among which positive but not completely maps are of particular interest as they characterize entangled states, a general resource in quantum information processing. Structural physical approximation offers a systematic way of approximating those non-physical maps, positive but not completely positive maps, with quantum channels. Since it has been proposed as a method of detecting entangled states, it has stimulated fundamental problems on classifications of positive maps and the structure of Hermitian operators and quantum states, as well as on quantum measurement such as quantum design in quantum information theory. It has developed efficient and feasible methods of directly detecting entangled states in practice, for which proof-of-principle experimental demonstrations have also been performed with photonic qubit states. Here, we present a comprehensive review on quantum information processing with structural physical approximations and the related progress. The review mainly focuses on properties of structural physical approximations and their applications toward practical information applications.

Designing quantum information processing via structural physical approximation

NASA Astrophysics Data System (ADS)

Bae, Joonwoo

2017-10-01

In quantum information processing it may be possible to have efficient computation and secure communication beyond the limitations of classical systems. In a fundamental point of view, however, evolution of quantum systems by the laws of quantum mechanics is more restrictive than classical systems, identified to a specific form of dynamics, that is, unitary transformations and, consequently, positive and completely positive maps to subsystems. This also characterizes classes of disallowed transformations on quantum systems, among which positive but not completely maps are of particular interest as they characterize entangled states, a general resource in quantum information processing. Structural physical approximation offers a systematic way of approximating those non-physical maps, positive but not completely positive maps, with quantum channels. Since it has been proposed as a method of detecting entangled states, it has stimulated fundamental problems on classifications of positive maps and the structure of Hermitian operators and quantum states, as well as on quantum measurement such as quantum design in quantum information theory. It has developed efficient and feasible methods of directly detecting entangled states in practice, for which proof-of-principle experimental demonstrations have also been performed with photonic qubit states. Here, we present a comprehensive review on quantum information processing with structural physical approximations and the related progress. The review mainly focuses on properties of structural physical approximations and their applications toward practical information applications.

Transitioning to Low-GWP Alternatives in Unitary Air Conditioning

EPA Pesticide Factsheets

This fact sheet provides current information on low-Global Warming Potential (GWP) refrigerant alternatives used in unitary air-conditioning equipment, relevant to the Montreal Protocol on Substances that Deplete the Ozone Layer.

The flexible focus: whether spatial attention is unitary or divided depends on observer goals.

PubMed

Jefferies, Lisa N; Enns, James T; Di Lollo, Vincent

2014-04-01

The distribution of visual attention has been the topic of much investigation, and various theories have posited that attention is allocated either as a single unitary focus or as multiple independent foci. In the present experiment, we demonstrate that attention can be flexibly deployed as either a unitary or a divided focus in the same experimental task, depending on the observer's goals. To assess the distribution of attention, we used a dual-stream Attentional Blink (AB) paradigm and 2 target pairs. One component of the AB, Lag-1 sparing, occurs only if the second target pair appears within the focus of attention. By varying whether the first-target-pair could be expected in a predictable location (always in-stream) or not (unpredictably in-stream or between-streams), observers were encouraged to deploy a divided or a unitary focus, respectively. When the second-target-pair appeared between the streams, Lag-1 sparing occurred for the Unpredictable group (consistent with a unitary focus) but not for the Predictable group (consistent with a divided focus). Thus, diametrically different outcomes occurred for physically identical displays, depending on the expectations of the observer about where spatial attention would be required.

The energy-level crossing behavior and quantum Fisher information in a quantum well with spin-orbit coupling

PubMed Central

Wang, Z. H.; Zheng, Q.; Wang, Xiaoguang; Li, Yong

2016-01-01

We study the energy-level crossing behavior in a two-dimensional quantum well with the Rashba and Dresselhaus spin-orbit couplings (SOCs). By mapping the SOC Hamiltonian onto an anisotropic Rabi model, we obtain the approximate ground state and its quantum Fisher information (QFI) via performing a unitary transformation. We find that the energy-level crossing can occur in the quantum well system within the available parameters rather than in cavity and circuit quantum eletrodynamics systems. Furthermore, the influence of two kinds of SOCs on the QFI is investigated and an intuitive explanation from the viewpoint of the stationary perturbation theory is given. PMID:26931762

The energy-level crossing behavior and quantum Fisher information in a quantum well with spin-orbit coupling.

PubMed

Wang, Z H; Zheng, Q; Wang, Xiaoguang; Li, Yong

2016-03-02

We study the energy-level crossing behavior in a two-dimensional quantum well with the Rashba and Dresselhaus spin-orbit couplings (SOCs). By mapping the SOC Hamiltonian onto an anisotropic Rabi model, we obtain the approximate ground state and its quantum Fisher information (QFI) via performing a unitary transformation. We find that the energy-level crossing can occur in the quantum well system within the available parameters rather than in cavity and circuit quantum eletrodynamics systems. Furthermore, the influence of two kinds of SOCs on the QFI is investigated and an intuitive explanation from the viewpoint of the stationary perturbation theory is given.

The energy-level crossing behavior and quantum Fisher information in a quantum well with spin-orbit coupling

NASA Astrophysics Data System (ADS)

Wang, Z. H.; Zheng, Q.; Wang, Xiaoguang; Li, Yong

2016-03-01

We study the energy-level crossing behavior in a two-dimensional quantum well with the Rashba and Dresselhaus spin-orbit couplings (SOCs). By mapping the SOC Hamiltonian onto an anisotropic Rabi model, we obtain the approximate ground state and its quantum Fisher information (QFI) via performing a unitary transformation. We find that the energy-level crossing can occur in the quantum well system within the available parameters rather than in cavity and circuit quantum eletrodynamics systems. Furthermore, the influence of two kinds of SOCs on the QFI is investigated and an intuitive explanation from the viewpoint of the stationary perturbation theory is given.

Subcritical Multiplicative Chaos for Regularized Counting Statistics from Random Matrix Theory

NASA Astrophysics Data System (ADS)

Lambert, Gaultier; Ostrovsky, Dmitry; Simm, Nick

2018-05-01

For an {N × N} Haar distributed random unitary matrix U N , we consider the random field defined by counting the number of eigenvalues of U N in a mesoscopic arc centered at the point u on the unit circle. We prove that after regularizing at a small scale {ɛN > 0}, the renormalized exponential of this field converges as N \\to ∞ to a Gaussian multiplicative chaos measure in the whole subcritical phase. We discuss implications of this result for obtaining a lower bound on the maximum of the field. We also show that the moments of the total mass converge to a Selberg-like integral and by taking a further limit as the size of the arc diverges, we establish part of the conjectures in Ostrovsky (Nonlinearity 29(2):426-464, 2016). By an analogous construction, we prove that the multiplicative chaos measure coming from the sine process has the same distribution, which strongly suggests that this limiting object should be universal. Our approach to the L 1-phase is based on a generalization of the construction in Berestycki (Electron Commun Probab 22(27):12, 2017) to random fields which are only asymptotically Gaussian. In particular, our method could have applications to other random fields coming from either random matrix theory or a different context.

Non-unitary probabilistic quantum computing circuit and method

NASA Technical Reports Server (NTRS)

Williams, Colin P. (Inventor); Gingrich, Robert M. (Inventor)

2009-01-01

A quantum circuit performing quantum computation in a quantum computer. A chosen transformation of an initial n-qubit state is probabilistically obtained. The circuit comprises a unitary quantum operator obtained from a non-unitary quantum operator, operating on an n-qubit state and an ancilla state. When operation on the ancilla state provides a success condition, computation is stopped. When operation on the ancilla state provides a failure condition, computation is performed again on the ancilla state and the n-qubit state obtained in the previous computation, until a success condition is obtained.

Multiple multicontrol unitary operations: Implementation and applications

NASA Astrophysics Data System (ADS)

Lin, Qing

2018-04-01

The efficient implementation of computational tasks is critical to quantum computations. In quantum circuits, multicontrol unitary operations are important components. Here, we present an extremely efficient and direct approach to multiple multicontrol unitary operations without decomposition to CNOT and single-photon gates. With the proposed approach, the necessary two-photon operations could be reduced from O( n 3) with the traditional decomposition approach to O( n), which will greatly relax the requirements and make large-scale quantum computation feasible. Moreover, we propose the potential application to the ( n- k)-uniform hypergraph state.

Consciousness, intentionality, and community: Unitary perspectives and research.

PubMed

Zahourek, Rothlyn P; Larkin, Dorothy M

2009-01-01

Consciousness and intentionality often have been related and studied together. These concepts also are readily viewed and understood for practice, research, and education in a unitary paradigm. How these ideas relate to community is less known. Considering the expansion of our capacity for communication through the World Wide Web and other technologic advances and appreciating recent research on the nonlocal character of intentionality and consciousness, it is more apparent how concepts of community can be seen in the same unitary context. The authors address these issues and review relevant nursing research.

On Probability Domains IV

NASA Astrophysics Data System (ADS)

Frič, Roman; Papčo, Martin

2017-12-01

Stressing a categorical approach, we continue our study of fuzzified domains of probability, in which classical random events are replaced by measurable fuzzy random events. In operational probability theory (S. Bugajski) classical random variables are replaced by statistical maps (generalized distribution maps induced by random variables) and in fuzzy probability theory (S. Gudder) the central role is played by observables (maps between probability domains). We show that to each of the two generalized probability theories there corresponds a suitable category and the two resulting categories are dually equivalent. Statistical maps and observables become morphisms. A statistical map can send a degenerated (pure) state to a non-degenerated one —a quantum phenomenon and, dually, an observable can map a crisp random event to a genuine fuzzy random event —a fuzzy phenomenon. The dual equivalence means that the operational probability theory and the fuzzy probability theory coincide and the resulting generalized probability theory has two dual aspects: quantum and fuzzy. We close with some notes on products and coproducts in the dual categories.

Exact mapping between system-reservoir quantum models and semi-infinite discrete chains using orthogonal polynomials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chin, Alex W.; Rivas, Angel; Huelga, Susana F.

2010-09-15

By using the properties of orthogonal polynomials, we present an exact unitary transformation that maps the Hamiltonian of a quantum system coupled linearly to a continuum of bosonic or fermionic modes to a Hamiltonian that describes a one-dimensional chain with only nearest-neighbor interactions. This analytical transformation predicts a simple set of relations between the parameters of the chain and the recurrence coefficients of the orthogonal polynomials used in the transformation and allows the chain parameters to be computed using numerically stable algorithms that have been developed to compute recurrence coefficients. We then prove some general properties of this chain systemmore » for a wide range of spectral functions and give examples drawn from physical systems where exact analytic expressions for the chain properties can be obtained. Crucially, the short-range interactions of the effective chain system permit these open-quantum systems to be efficiently simulated by the density matrix renormalization group methods.« less

Feature Integration in the Mapping of Multi-Attribute Visual Stimuli to Responses

PubMed Central

Ishizaki, Takuya; Morita, Hiromi; Morita, Masahiko

2015-01-01

In the human visual system, different attributes of an object, such as shape and color, are separately processed in different modules and then integrated to elicit a specific response. In this process, different attributes are thought to be temporarily “bound” together by focusing attention on the object; however, how such binding contributes to stimulus-response mapping remains unclear. Here we report that learning and performance of stimulus-response tasks was more difficult when three attributes of the stimulus determined the correct response than when two attributes did. We also found that spatially separated presentations of attributes considerably complicated the task, although they did not markedly affect target detection. These results are consistent with a paired-attribute model in which bound feature pairs, rather than object representations, are associated with responses by learning. This suggests that attention does not bind three or more attributes into a unitary object representation, and long-term learning is required for their integration. PMID:25762010

Procedures and requirements for testing in the Langley Research Center unitary plan wind tunnel

NASA Technical Reports Server (NTRS)

Wassum, Donald L.; Hyman, Curtis E., Jr.

1988-01-01

Information is presented to assist those interested in conducting wind-tunnel testing within the Langley Unitary Plan Wind Tunnel. Procedures, requirements, forms and examples necessary for tunnel entry are included.

Compressor-fan unitary structure for air conditioning system

NASA Astrophysics Data System (ADS)

Dreiman, N.

2015-08-01

An extremely compact, therefore space saving unitary structure of short axial length is produced by radial integration of a revolving piston rotary compressor and an impeller of a centrifugal fan. The unitary structure employs single motor to run as the compressor so the airflow fan and eliminates duality of motors, related power supply and control elements. Novel revolving piston rotary compressor which provides possibility for such integration comprises the following: a suction gas delivery system which provides cooling of the motor and supplies refrigerant into the suction chamber under higher pressure (supercharged); a modified discharge system and lubricating oil supply system. Axial passages formed in the stationary crankshaft are used to supply discharge gas to a condenser, to return vaporized cooling agent from the evaporator to the suction cavity of the compressor, to pass a lubricant and to accommodate wiring supplying power to the unitary structure driver -external rotor electric motor.

Gauge-origin independent formalism of two-component relativistic framework based on unitary transformation in nuclear magnetic shielding constant

NASA Astrophysics Data System (ADS)

Hayami, Masao; Seino, Junji; Nakai, Hiromi

2018-03-01

This article proposes a gauge-origin independent formalism of the nuclear magnetic shielding constant in the two-component relativistic framework based on the unitary transformation. The proposed scheme introduces the gauge factor and the unitary transformation into the atomic orbitals. The two-component relativistic equation is formulated by block-diagonalizing the Dirac Hamiltonian together with gauge factors. This formulation is available for arbitrary relativistic unitary transformations. Then, the infinite-order Douglas-Kroll-Hess (IODKH) transformation is applied to the present formulation. Next, the analytical derivatives of the IODKH Hamiltonian for the evaluation of the nuclear magnetic shielding constant are derived. Results obtained from the numerical assessments demonstrate that the present formulation removes the gauge-origin dependence completely. Furthermore, the formulation with the IODKH transformation gives results that are close to those in four-component and other two-component relativistic schemes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Livine, Etera R.

We introduce the set of framed (convex) polyhedra with N faces as the symplectic quotient C{sup 2N}//SU(2). A framed polyhedron is then parametrized by N spinors living in C{sup 2} satisfying suitable closure constraints and defines a usual convex polyhedron plus extra U(1) phases attached to each face. We show that there is a natural action of the unitary group U(N) on this phase space, which changes the shape of faces and allows to map any (framed) polyhedron onto any other with the same total (boundary) area. This identifies the space of framed polyhedra to the Grassmannian space U(N)/ (SU(2)×U(N−2)).more » We show how to write averages of geometrical observables (polynomials in the faces' area and the angles between them) over the ensemble of polyhedra (distributed uniformly with respect to the Haar measure on U(N)) as polynomial integrals over the unitary group and we provide a few methods to compute these integrals systematically. We also use the Itzykson-Zuber formula from matrix models as the generating function for these averages and correlations. In the quantum case, a canonical quantization of the framed polyhedron phase space leads to the Hilbert space of SU(2) intertwiners (or, in other words, SU(2)-invariant states in tensor products of irreducible representations). The total boundary area as well as the individual face areas are quantized as half-integers (spins), and the Hilbert spaces for fixed total area form irreducible representations of U(N). We define semi-classical coherent intertwiner states peaked on classical framed polyhedra and transforming consistently under U(N) transformations. And we show how the U(N) character formula for unitary transformations is to be considered as an extension of the Itzykson-Zuber to the quantum level and generates the traces of all polynomial observables over the Hilbert space of intertwiners. We finally apply the same formalism to two dimensions and show that classical (convex) polygons can be described in a similar fashion trading the unitary group for the orthogonal group. We conclude with a discussion of the possible (deformation) dynamics that one can define on the space of polygons or polyhedra. This work is a priori useful in the context of discrete geometry but it should hopefully also be relevant to (loop) quantum gravity in 2+1 and 3+1 dimensions when the quantum geometry is defined in terms of gluing of (quantized) polygons and polyhedra.« less

Exploring the Structure of Spatial Representations

PubMed Central

Madl, Tamas; Franklin, Stan; Chen, Ke; Trappl, Robert; Montaldi, Daniela

2016-01-01

It has been suggested that the map-like representations that support human spatial memory are fragmented into sub-maps with local reference frames, rather than being unitary and global. However, the principles underlying the structure of these ‘cognitive maps’ are not well understood. We propose that the structure of the representations of navigation space arises from clustering within individual psychological spaces, i.e. from a process that groups together objects that are close in these spaces. Building on the ideas of representational geometry and similarity-based representations in cognitive science, we formulate methods for learning dissimilarity functions (metrics) characterizing participants’ psychological spaces. We show that these learned metrics, together with a probabilistic model of clustering based on the Bayesian cognition paradigm, allow prediction of participants’ cognitive map structures in advance. Apart from insights into spatial representation learning in human cognition, these methods could facilitate novel computational tools capable of using human-like spatial concepts. We also compare several features influencing spatial memory structure, including spatial distance, visual similarity and functional similarity, and report strong correlations between these dimensions and the grouping probability in participants’ spatial representations, providing further support for clustering in spatial memory. PMID:27347681

Real time visualization of quantum walk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyazaki, Akihide; Hamada, Shinji; Sekino, Hideo

2014-02-20

Time evolution of quantum particles like electrons is described by time-dependent Schrödinger equation (TDSE). The TDSE is regarded as the diffusion equation of electrons with imaginary diffusion coefficients. And the TDSE is solved by quantum walk (QW) which is regarded as a quantum version of a classical random walk. The diffusion equation is solved in discretized space/time as in the case of classical random walk with additional unitary transformation of internal degree of freedom typical for quantum particles. We call the QW for solution of the TDSE a Schrödinger walk (SW). For observation of one quantum particle evolution under amore » given potential in atto-second scale, we attempt a successive computation and visualization of the SW. Using Pure Data programming, we observe the correct behavior of a probability distribution under the given potential in real time for observers of atto-second scale.« less

Foundations of statistical mechanics from symmetries of entanglement

DOE PAGES

Deffner, Sebastian; Zurek, Wojciech H.

2016-06-09

Envariance—entanglement assisted invariance—is a recently discovered symmetry of composite quantum systems. Here, we show that thermodynamic equilibrium states are fully characterized by their envariance. In particular, the microcanonical equilibrium of a systemmore » $${ \\mathcal S }$$ with Hamiltonian $${H}_{{ \\mathcal S }}$$ is a fully energetically degenerate quantum state envariant under every unitary transformation. A representation of the canonical equilibrium then follows from simply counting degenerate energy states. Finally, our conceptually novel approach is free of mathematically ambiguous notions such as ensemble, randomness, etc., and, while it does not even rely on probability, it helps to understand its role in the quantum world.« less

On the time arrows, and randomness in cosmological signals

NASA Astrophysics Data System (ADS)

Gurzadyan, V. G.; Sargsyan, S.; Yegorian, G.

2013-09-01

Arrows of time - thermodynamical, cosmological, electromagnetic, quantum mechanical, psychological - are basic properties of Nature. For a quantum system-bath closed system the de-correlated initial conditions and no-memory (Markovian) dynamics are outlined as necessary conditions for the appearance of the thermodynamical arrow. The emergence of the arrow for the system evolving according to non-unitary dynamics due to the presence of the bath, then, is a result of limited observability, and we conjecture the arrow in the observable Universe as determined by the dark sector acting as a bath. The voids in the large scale matter distribution induce hyperbolicity of the null geodesics, with possible observational consequences.

Universal quantum computation with temporal-mode bilayer square lattices

NASA Astrophysics Data System (ADS)

Alexander, Rafael N.; Yokoyama, Shota; Furusawa, Akira; Menicucci, Nicolas C.

2018-03-01

We propose an experimental design for universal continuous-variable quantum computation that incorporates recent innovations in linear-optics-based continuous-variable cluster state generation and cubic-phase gate teleportation. The first ingredient is a protocol for generating the bilayer-square-lattice cluster state (a universal resource state) with temporal modes of light. With this state, measurement-based implementation of Gaussian unitary gates requires only homodyne detection. Second, we describe a measurement device that implements an adaptive cubic-phase gate, up to a random phase-space displacement. It requires a two-step sequence of homodyne measurements and consumes a (non-Gaussian) cubic-phase state.

Current algebras, measures quasi-invariant under diffeomorphism groups, and infinite quantum systems with accumulation points

NASA Astrophysics Data System (ADS)

Sakuraba, Takao

The approach to quantum physics via current algebra and unitary representations of the diffeomorphism group is established. This thesis studies possible infinite Bose gas systems using this approach. Systems of locally finite configurations and systems of configurations with accumulation points are considered, with the main emphasis on the latter. In Chapter 2, canonical quantization, quantization via current algebra and unitary representations of the diffeomorphism group are reviewed. In Chapter 3, a new definition of the space of configurations is proposed and an axiom for general configuration spaces is abstracted. Various subsets of the configuration space, including those specifying the number of points in a Borel set and those specifying the number of accumulation points in a Borel set are proved to be measurable using this axiom. In Chapter 4, known results on the space of locally finite configurations and Poisson measure are reviewed in the light of the approach developed in Chapter 3, including the approach to current algebra in the Poisson space by Albeverio, Kondratiev, and Rockner. Goldin and Moschella considered unitary representations of the group of diffeomorphisms of the line based on self-similar random processes, which may describe infinite quantum gas systems with clusters. In Chapter 5, the Goldin-Moschella theory is developed further. Their construction of measures quasi-invariant under diffeomorphisms is reviewed, and a rigorous proof of their conjectures is given. It is proved that their measures with distinct correlation parameters are mutually singular. A quasi-invariant measure constructed by Ismagilov on the space of configurations with accumulation points on the circle is proved to be singular with respect to the Goldin-Moschella measures. Finally a generalization of the Goldin-Moschella measures to the higher-dimensional case is studied, where the notion of covariance matrix and the notion of condition number play important roles. A rigorous construction of measures quasi-invariant under the group of diffeomorphisms of d-dimensional space stabilizing a point is given.

The Unitary Plan Wind Tunnel(UPWT) Test 1891 Space Launch System

NASA Image and Video Library

2014-10-15

Stage Separation Test of the Space Launch System(SLS) in the Langley Unitary Plan Wind Tunnel (UPWT). The model used High Pressure air blown through the solid rocket boosters. (SRB) to simulate the booster separation motors (BSM) firing.

The Unitary Plan Wind Tunnel(UPWT) Test 1891 Space Launch System

NASA Image and Video Library

2014-10-14

Stage Separation Test of the Space Launch System(SLS) in the Langley Unitary Plan Wind Tunnel (UPWT). The model used High Pressure air blown through the solid rocket boosters. (SRB) to simulate the booster separation motors (BSM) firing.

Representation and design of wavelets using unitary circuits

NASA Astrophysics Data System (ADS)

Evenbly, Glen; White, Steven R.

2018-05-01

The representation of discrete, compact wavelet transformations (WTs) as circuits of local unitary gates is discussed. We employ a similar formalism as used in the multiscale representation of quantum many-body wave functions using unitary circuits, further cementing the relation established in the literature between classical and quantum multiscale methods. An algorithm for constructing the circuit representation of known orthogonal, dyadic, discrete WTs is presented, and the explicit representation for Daubechies wavelets, coiflets, and symlets is provided. Furthermore, we demonstrate the usefulness of the circuit formalism in designing WTs, including various classes of symmetric wavelets and multiwavelets, boundary wavelets, and biorthogonal wavelets.

How many invariant polynomials are needed to decide local unitary equivalence of qubit states?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maciążek, Tomasz; Faculty of Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa; Oszmaniec, Michał

2013-09-15

Given L-qubit states with the fixed spectra of reduced one-qubit density matrices, we find a formula for the minimal number of invariant polynomials needed for solving local unitary (LU) equivalence problem, that is, problem of deciding if two states can be connected by local unitary operations. Interestingly, this number is not the same for every collection of the spectra. Some spectra require less polynomials to solve LU equivalence problem than others. The result is obtained using geometric methods, i.e., by calculating the dimensions of reduced spaces, stemming from the symplectic reduction procedure.

Pseudo-random bit generator based on lag time series

NASA Astrophysics Data System (ADS)

García-Martínez, M.; Campos-Cantón, E.

2014-12-01

In this paper, we present a pseudo-random bit generator (PRBG) based on two lag time series of the logistic map using positive and negative values in the bifurcation parameter. In order to hidden the map used to build the pseudo-random series we have used a delay in the generation of time series. These new series when they are mapped xn against xn+1 present a cloud of points unrelated to the logistic map. Finally, the pseudo-random sequences have been tested with the suite of NIST giving satisfactory results for use in stream ciphers.

Full allogeneic fusion of embryos in a holothuroid echinoderm.

PubMed

Gianasi, Bruno L; Hamel, Jean-François; Mercier, Annie

2018-05-30

Whole-body chimaeras (organisms composed of genetically distinct cells) have been directly observed in modular/colonial organisms (e.g. corals, sponges, ascidians); whereas in unitary deuterostosmes (including mammals) they have only been detected indirectly through molecular analysis. Here, we document for the first time the step-by-step development of whole-body chimaeras in the holothuroid Cucumaria frondosa , a unitary deuterostome belonging to the phylum Echinodermata. To the best of our knowledge, this is the most derived unitary metazoan in which direct investigation of zygote fusibility has been undertaken. Fusion occurred among hatched blastulae, never during earlier (unhatched) or later (larval) stages. The fully fused chimaeric propagules were two to five times larger than non-chimaeric embryos. Fusion was positively correlated with propagule density and facilitated by the natural tendency of early embryos to agglomerate. The discovery of natural chimaerism in a unitary deuterostome that possesses large externally fertilized eggs provides a framework to explore key aspects of evolutionary biology, histocompatibility and cell transplantation in biomedical research. © 2018 The Author(s).

Informational correlation between two parties of a quantum system: spin-1/2 chains

NASA Astrophysics Data System (ADS)

Zenchuk, A. I.

2014-12-01

We introduce the informational correlation between two interacting quantum subsystems and of a quantum system as the number of arbitrary parameters of a unitary transformation (locally performed on the subsystem ) which may be detected in the subsystem by the local measurements. This quantity indicates whether the state of the subsystem may be effected by means of the unitary transformation applied to the subsystem . Emphasize that in general. The informational correlations in systems with tensor product initial states are studied in more details. In particular, it is shown that the informational correlation may be changed by the local unitary transformations of the subsystem . However, there is some non-reducible part of which may not be decreased by any unitary transformation of the subsystem at a fixed time instant . Two examples of the informational correlations between two parties of the four-node spin-1/2 chain with mixed initial states are studied. The long chains with a single initially excited spin (the pure initial state) are considered as well.

Heisenberg symmetry and collective modes of one dimensional unitary correlated fermions

NASA Astrophysics Data System (ADS)

Abhinav, Kumar; Chandrasekhar, B.; Vyas, Vivek M.; Panigrahi, Prasanta K.

2017-02-01

The correlated fermionic many-particle system, near infinite scattering length, reveals an underlying Heisenberg symmetry in one dimension, as compared to an SO (2 , 1) symmetry in two dimensions. This facilitates an exact map from the interacting to the non-interacting system, both with and without a harmonic trap, and explains the short-distance scaling behavior of the wave-function. Taking advantage of the phenomenological Calogero-Sutherland-type interaction, motivated by the density functional approach, we connect the ground-state energy shift, to many-body correlation effect. For the excited states, modes at integral values of the harmonic frequency ω are predicted in one dimension, in contrast to the breathing modes with frequency 2ω in two dimensions.

Matrix elements for type 1 unitary irreducible representations of the Lie superalgebra gl(m|n)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gould, Mark D.; Isaac, Phillip S.; Werry, Jason L.

Using our recent results on eigenvalues of invariants associated to the Lie superalgebra gl(m|n), we use characteristic identities to derive explicit matrix element formulae for all gl(m|n) generators, particularly non-elementary generators, on finite dimensional type 1 unitary irreducible representations. We compare our results with existing works that deal with only subsets of the class of type 1 unitary representations, all of which only present explicit matrix elements for elementary generators. Our work therefore provides an important extension to existing methods, and thus highlights the strength of our techniques which exploit the characteristic identities.

Study of optical techniques for the Ames unitary wind tunnel, part 7

NASA Technical Reports Server (NTRS)

Lee, George

1993-01-01

A summary of optical techniques for the Ames Unitary Plan wind tunnels are discussed. Six optical techniques were studied: Schlieren, light sheet and laser vapor screen, angle of attack, model deformation, infrared imagery, and digital image processing. The study includes surveys and reviews of wind tunnel optical techniques, some conceptual designs, and recommendations for use of optical methods in the Ames Unitary Plan wind tunnels. Particular emphasis was placed on searching for systems developed for wind tunnel use and on commercial systems which could be readily adapted for wind tunnels. This final report is to summarize the major results and recommendations.

An exploration of the perception of time from the perspective of the Science of Unitary Human Beings.

PubMed

Ring, Marcia E

2009-01-01

What is time? The science of unitary human beings describes pandimensional reality as a domain without spatial or temporal attributes. As part of this pandimensional reality, unitary human beings experience time as passing, and involving the past, present, and future. The theory of accelerating evolution describes changes in human and environmental energy fields that are always accelerating and are manifested as differences in the experience of time as being slow, fast, and still. Time, be it measured or experienced, has no meaning in and of itself, but can only be understood in terms of the ever-evolving life process.

Polynomial approximation of non-Gaussian unitaries by counting one photon at a time

NASA Astrophysics Data System (ADS)

Arzani, Francesco; Treps, Nicolas; Ferrini, Giulia

2017-05-01

In quantum computation with continuous-variable systems, quantum advantage can only be achieved if some non-Gaussian resource is available. Yet, non-Gaussian unitary evolutions and measurements suited for computation are challenging to realize in the laboratory. We propose and analyze two methods to apply a polynomial approximation of any unitary operator diagonal in the amplitude quadrature representation, including non-Gaussian operators, to an unknown input state. Our protocols use as a primary non-Gaussian resource a single-photon counter. We use the fidelity of the transformation with the target one on Fock and coherent states to assess the quality of the approximate gate.

The unitary life pattern of persons experiencing serenity in recovery from alcohol and drug addiction.

PubMed

Rushing, Alison M

2008-01-01

People recovering from addiction to alcohol or drugs often acknowledge the need for complete change in life pattern orientation in a journey toward healing. Serenity is the hallmark of recovery according to the tenets of 12-step programs, but little is known about the actual experience of serenity in healing from addiction. From a perspective of unitary pattern appreciation and a method of unitary appreciative inquiry, this study explored the experience of serenity among 9 people recovering from alcohol and/or drug addiction. Results are portrayed in both individual and group profiles, depicted in a format that integrates empirical findings as poetry.

Quantum mechanics in noninertial reference frames: Relativistic accelerations and fictitious forces

NASA Astrophysics Data System (ADS)

Klink, W. H.; Wickramasekara, S.

2016-06-01

One-particle systems in relativistically accelerating reference frames can be associated with a class of unitary representations of the group of arbitrary coordinate transformations, an extension of the Wigner-Bargmann definition of particles as the physical realization of unitary irreducible representations of the Poincaré group. Representations of the group of arbitrary coordinate transformations become necessary to define unitary operators implementing relativistic acceleration transformations in quantum theory because, unlike in the Galilean case, the relativistic acceleration transformations do not themselves form a group. The momentum operators that follow from these representations show how the fictitious forces in noninertial reference frames are generated in quantum theory.

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning...) Mechanical air conditioners shall be rated in accordance with the ARI Standard 210/240-89 Unitary Air Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning...) Mechanical air conditioners shall be rated in accordance with the ARI Standard 210/240-89 Unitary Air Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

Geometrically controlled evolution of four-qubit states

NASA Astrophysics Data System (ADS)

Duy, Hoang Ngoc; Heydari, Hoshang

2011-03-01

In this paper the evolution of some states of four qubits in [1] under global bipartite unitary operation and controlled by local unitary operation using four-tangle [2] and the geometric invariants [3] is investigated. Particularly the entanglement distribution and properties of these four-qubit states are studied.

An application of quantile random forests for predictive mapping of forest attributes

Treesearch

E.A. Freeman; G.G. Moisen

2015-01-01

Increasingly, random forest models are used in predictive mapping of forest attributes. Traditional random forests output the mean prediction from the random trees. Quantile regression forests (QRF) is an extension of random forests developed by Nicolai Meinshausen that provides non-parametric estimates of the median predicted value as well as prediction quantiles. It...

Establishing the Unitary Classroom: Organizational Change and School Culture.

ERIC Educational Resources Information Center

Eddy, Elizabeth M.; True, Joan H.

1980-01-01

This paper examines the organizational changes introduced in two elementary schools to create unitary (desegregated) classrooms. The different models adopted by the two schools--departmentalization and team teaching--are considered as expressions of their patterns of interaction, behavior, and values. (Part of a theme issue on educational…

ARC-2006-ACD06-0213-011

NASA Image and Video Library

2006-10-03

Ames and Moffett Field (MFA) historical sites and memorials Unitary Plan Wind Tunned plaza; display and historical site plaques with the NASA logo on the Wind Tunnel valve as a backdrop. shown is the Unitary International Historic Mechanical Engineering Landmark Dedication plaque (American Society of Mechanical Engineers) May 5, 1995

IRBM in Unitary Plan Wind Tunnel

NASA Image and Video Library

1957-09-07

L57-700 In the reentry flight path of this nose cone model of a Jupiter Intermediate range ballistic missile (IRBM) was tested in the Unitary Plan Wind Tunnel. Photograph published in Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958 by James R. Hansen. Page 475.

Prevention of Child Abuse: Theory, Myth, Practice.

ERIC Educational Resources Information Center

Newberger, Eli H.; Newberger, Carolyn Moore

Child abuse is discussed in terms of theory which when realized may lead to more effective primary and secondary prevention efforts. Theoretical explanations of child abuse are classified as either unitary or interactive. Unitary theories (psychological, sociological, and legal views of behavior) are considered deficient; none is capable of…

Renormalization of the unitary evolution equation for coined quantum walks

NASA Astrophysics Data System (ADS)

Boettcher, Stefan; Li, Shanshan; Portugal, Renato

2017-03-01

We consider discrete-time evolution equations in which the stochastic operator of a classical random walk is replaced by a unitary operator. Such a problem has gained much attention as a framework for coined quantum walks that are essential for attaining the Grover limit for quantum search algorithms in physically realizable, low-dimensional geometries. In particular, we analyze the exact real-space renormalization group (RG) procedure recently introduced to study the scaling of quantum walks on fractal networks. While this procedure, when implemented numerically, was able to provide some deep insights into the relation between classical and quantum walks, its analytic basis has remained obscure. Our discussion here is laying the groundwork for a rigorous implementation of the RG for this important class of transport and algorithmic problems, although some instances remain unresolved. Specifically, we find that the RG fixed-point analysis of the classical walk, which typically focuses on the dominant Jacobian eigenvalue {λ1} , with walk dimension dw\\text{RW}={{log}2}{λ1} , needs to be extended to include the subdominant eigenvalue {λ2} , such that the dimension of the quantum walk obtains dw\\text{QW}={{log}2}\\sqrt{{λ1}{λ2}} . With that extension, we obtain analytically previously conjectured results for dw\\text{QW} of Grover walks on all but one of the fractal networks that have been considered.

'Einselection' of pointer observables: The new H-theorem?

NASA Astrophysics Data System (ADS)

Kastner, Ruth E.

2014-11-01

In attempting to derive irreversible macroscopic thermodynamics from reversible microscopic dynamics, Boltzmann inadvertently smuggled in a premise that assumed the very irreversibility he was trying to prove: 'molecular chaos'. The program of 'einselection' (environmentally induced superselection) within Everettian approaches faces a similar 'Loschmidt's Paradox': the universe, according to the Everettian picture, is a closed system obeying only unitary dynamics, and it therefore contains no distinguishable environmental subsystems with the necessary 'phase randomness' to effect einselection of a pointer observable. The theoretically unjustified assumption of distinguishable environmental subsystems is the hidden premise that makes the derivation of einselection circular. In effect, it presupposes the 'emergent' structures from the beginning. Thus the problem of basis ambiguity remains unsolved in Everettian interpretations.

Spin-wave utilization in a quantum computer

NASA Astrophysics Data System (ADS)

Khitun, A.; Ostroumov, R.; Wang, K. L.

2001-12-01

We propose a quantum computer scheme using spin waves for quantum-information exchange. We demonstrate that spin waves in the antiferromagnetic layer grown on silicon may be used to perform single-qubit unitary transformations together with two-qubit operations during the cycle of computation. The most attractive feature of the proposed scheme is the possibility of random access to any qubit and, consequently, the ability to recognize two qubit gates between any two distant qubits. Also, spin waves allow us to eliminate the use of a strong external magnetic field and microwave pulses. By estimate, the proposed scheme has as high as 104 ratio between quantum system coherence time and the time of a single computational step.

X-ray light curves of active galactic nuclei are phase incoherent

NASA Technical Reports Server (NTRS)

Krolik, Julian; Done, Chris; Madejski, Grzegorz

1993-01-01

We compute the Fourier phase spectra for the light curves of five low-luminosity active galactic nuclei observed by EXOSAT. There is no statistically significant phase coherence in any of them. This statement is equivalent, subject to a technical caveat, to a demonstration that their fluctuation statistics are Gaussian. Models in which the X-ray output is controlled wholly by a unitary process undergoing a nonlinear limit cycle are therefore ruled out, while models with either a large number of randomly excited independent oscillation modes or nonlinearly interacting spatially dependent oscillations are favored. We also demonstrate how the degree of phase coherence in light curve fluctuations influences the application of causality bounds on internal length scales.

Algebraic special functions and SO(3,2)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Celeghini, E., E-mail: celeghini@fi.infn.it; Olmo, M.A. del, E-mail: olmo@fta.uva.es

2013-06-15

A ladder structure of operators is presented for the associated Legendre polynomials and the sphericas harmonics. In both cases these operators belong to the irreducible representation of the Lie algebra so(3,2) with quadratic Casimir equals to −5/4. As both are also bases of square-integrable functions, the universal enveloping algebra of so(3,2) is thus shown to be homomorphic to the space of linear operators acting on the L{sup 2} functions defined on (−1,1)×Z and on the sphere S{sup 2}, respectively. The presence of a ladder structure is suggested to be the general condition to obtain a Lie algebra representation defining inmore » this way the “algebraic special functions” that are proposed to be the connection between Lie algebras and square-integrable functions so that the space of linear operators on the L{sup 2} functions is homomorphic to the universal enveloping algebra. The passage to the group, by means of the exponential map, shows that the associated Legendre polynomials and the spherical harmonics support the corresponding unitary irreducible representation of the group SO(3,2). -- Highlights: •The algebraic ladder structure is constructed for the associated Legendre polynomials (ALP). •ALP and spherical harmonics support a unitary irreducible SO(3,2)-representation. •A ladder structure is the condition to get a Lie group representation defining “algebraic special functions”. •The “algebraic special functions” connect Lie algebras and L{sup 2} functions.« less

An Application of the Theory of Moments to Euclidean Relativistic Quantum Mechanical Scattering

NASA Astrophysics Data System (ADS)

Aiello, Gordon J.

One recipe for mathematically formulating a relativistic quantum mechanical scattering theory utilizes a two-Hilbert space approach, denoted by H and H0, upon each of which a unitary representation of the Poincare Lie group is given. Physically speaking, H models a complicated interacting system of particles one wishes to understand, and H 0 an associated simpler (i.e., free/noninteracting) structure one uses to construct "asymptotic boundary conditions" on so-called scattering states in H. Simply put, H 0 is an attempted idealization of H one hopes to realize in the large time limits t → +/-infinity. The above considerations lead to the study of the existence of strong limits of operators of the form eiHtJeiH 0t, where H and H0 are self-adjoint generators of the time translation subgroup of the unitary representations of the Poincare group on H and H0, and J is a contrived mapping from H0 into H that provides the internal structure of the scattering asymptotes. The existence of said limits in the context of Euclidean quantum theories (satisfying precepts known as the Osterwalder-Schrader axioms) depends on the choice of J and leads to a marvelous connection between this formalism and a beautiful area of classical mathematical analysis known as the Stieltjes moment problem, which concerns the relationship between numerical sequences {mun}n=0infinity and the existence/uniqueness of measures alpha(x) on the half-line satisfying (n/a).

Comparing the Performance of Japan's Earthquake Hazard Maps to Uniform and Randomized Maps

NASA Astrophysics Data System (ADS)

Brooks, E. M.; Stein, S. A.; Spencer, B. D.

2015-12-01

The devastating 2011 magnitude 9.1 Tohoku earthquake and the resulting shaking and tsunami were much larger than anticipated in earthquake hazard maps. Because this and all other earthquakes that caused ten or more fatalities in Japan since 1979 occurred in places assigned a relatively low hazard, Geller (2011) argued that "all of Japan is at risk from earthquakes, and the present state of seismological science does not allow us to reliably differentiate the risk level in particular geographic areas," so a map showing uniform hazard would be preferable to the existing map. Defenders of the maps countered by arguing that these earthquakes are low-probability events allowed by the maps, which predict the levels of shaking that should expected with a certain probability over a given time. Although such maps are used worldwide in making costly policy decisions for earthquake-resistant construction, how well these maps actually perform is unknown. We explore this hotly-contested issue by comparing how well a 510-year-long record of earthquake shaking in Japan is described by the Japanese national hazard (JNH) maps, uniform maps, and randomized maps. Surprisingly, as measured by the metric implicit in the JNH maps, i.e. that during the chosen time interval the predicted ground motion should be exceeded only at a specific fraction of the sites, both uniform and randomized maps do better than the actual maps. However, using as a metric the squared misfit between maximum observed shaking and that predicted, the JNH maps do better than uniform or randomized maps. These results indicate that the JNH maps are not performing as well as expected, that what factors control map performance is complicated, and that learning more about how maps perform and why would be valuable in making more effective policy.

The second law of thermodynamics under unitary evolution and external operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikeda, Tatsuhiko N., E-mail: ikeda@cat.phys.s.u-tokyo.ac.jp; Physics Department, Boston University, Boston, MA 02215; Sakumichi, Naoyuki

The von Neumann entropy cannot represent the thermodynamic entropy of equilibrium pure states in isolated quantum systems. The diagonal entropy, which is the Shannon entropy in the energy eigenbasis at each instant of time, is a natural generalization of the von Neumann entropy and applicable to equilibrium pure states. We show that the diagonal entropy is consistent with the second law of thermodynamics upon arbitrary external unitary operations. In terms of the diagonal entropy, thermodynamic irreversibility follows from the facts that quantum trajectories under unitary evolution are restricted by the Hamiltonian dynamics and that the external operation is performed withoutmore » reference to the microscopic state of the system.« less

Reflection Positive Stochastic Processes Indexed by Lie Groups

NASA Astrophysics Data System (ADS)

Jorgensen, Palle E. T.; Neeb, Karl-Hermann; Ólafsson, Gestur

2016-06-01

Reflection positivity originates from one of the Osterwalder-Schrader axioms for constructive quantum field theory. It serves as a bridge between euclidean and relativistic quantum field theory. In mathematics, more specifically, in representation theory, it is related to the Cartan duality of symmetric Lie groups (Lie groups with an involution) and results in a transformation of a unitary representation of a symmetric Lie group to a unitary representation of its Cartan dual. In this article we continue our investigation of representation theoretic aspects of reflection positivity by discussing reflection positive Markov processes indexed by Lie groups, measures on path spaces, and invariant gaussian measures in spaces of distribution vectors. This provides new constructions of reflection positive unitary representations.

Single-particle spectral density of the unitary Fermi gas: Novel approach based on the operator product expansion, sum rules and the maximum entropy method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gubler, Philipp, E-mail: pgubler@riken.jp; RIKEN Nishina Center, Wako, Saitama 351-0198; Yamamoto, Naoki

2015-05-15

Making use of the operator product expansion, we derive a general class of sum rules for the imaginary part of the single-particle self-energy of the unitary Fermi gas. The sum rules are analyzed numerically with the help of the maximum entropy method, which allows us to extract the single-particle spectral density as a function of both energy and momentum. These spectral densities contain basic information on the properties of the unitary Fermi gas, such as the dispersion relation and the superfluid pairing gap, for which we obtain reasonable agreement with the available results based on quantum Monte-Carlo simulations.

Surface effects in the unitary Fermi gas

NASA Astrophysics Data System (ADS)

Salasnich, L.; Ancilotto, F.; Toigo, F.

2010-01-01

We study the extended Thomas-Fermi (ETF) density functional of the superfluid unitary Fermi gas. This functional includes a gradient term which is essential to describe accurately the surface effects of the system, in particular with a small number of atoms, where the Thomas-Fermi (local density) approximation fails. We find that our ETF functional gives density profiles which are in good agreement with recent Monte Carlo results and also with a more sophisticated superfluid density functional based on Bogoliubov-de Gennes equations. In addition, by using extended hydrodynamics equations of superfluids, we calculate the frequencies of collective surface oscillations of the unitary Fermi gas, showing that quadrupole and octupole modes strongly depend on the number of trapped atoms.

Quantum mechanics in noninertial reference frames: Relativistic accelerations and fictitious forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klink, W.H., E-mail: william-klink@uiowa.edu; Wickramasekara, S., E-mail: wickrama@grinnell.edu

2016-06-15

One-particle systems in relativistically accelerating reference frames can be associated with a class of unitary representations of the group of arbitrary coordinate transformations, an extension of the Wigner–Bargmann definition of particles as the physical realization of unitary irreducible representations of the Poincaré group. Representations of the group of arbitrary coordinate transformations become necessary to define unitary operators implementing relativistic acceleration transformations in quantum theory because, unlike in the Galilean case, the relativistic acceleration transformations do not themselves form a group. The momentum operators that follow from these representations show how the fictitious forces in noninertial reference frames are generated inmore » quantum theory.« less

Dynamics of Three-Body Correlations in Quenched Unitary Bose Gases

NASA Astrophysics Data System (ADS)

Colussi, V. E.; Corson, J. P.; D'Incao, J. P.

2018-03-01

We investigate dynamical three-body correlations in the Bose gas during the earliest stages of evolution after a quench to the unitary regime. The development of few-body correlations is theoretically observed by determining the two- and three-body contacts. We find that the growth of three-body correlations is gradual compared to two-body correlations. The three-body contact oscillates coherently, and we identify this as a signature of Efimov trimers. We show that the growth of three-body correlations depends nontrivially on parameters derived from both the density and Efimov physics. These results demonstrate the violation of scaling invariance of unitary bosonic systems via the appearance of log-periodic modulation of three-body correlations.

Continued-fraction representation of the Kraus map for non-Markovian reservoir damping

NASA Astrophysics Data System (ADS)

van Wonderen, A. J.; Suttorp, L. G.

2018-04-01

Quantum dissipation is studied for a discrete system that linearly interacts with a reservoir of harmonic oscillators at thermal equilibrium. Initial correlations between system and reservoir are assumed to be absent. The dissipative dynamics as determined by the unitary evolution of system and reservoir is described by a Kraus map consisting of an infinite number of matrices. For all Laplace-transformed Kraus matrices exact solutions are constructed in terms of continued fractions that depend on the pair correlation functions of the reservoir. By performing factorizations in the Kraus map a perturbation theory is set up that conserves in arbitrary perturbative order both positivity and probability of the density matrix. The latter is determined by an integral equation for a bitemporal matrix and a finite hierarchy for Kraus matrices. In the lowest perturbative order this hierarchy reduces to one equation for one Kraus matrix. Its solution is given by a continued fraction of a much simpler structure as compared to the non-perturbative case. In the lowest perturbative order our non-Markovian evolution equations are applied to the damped Jaynes–Cummings model. From the solution for the atomic density matrix it is found that the atom may remain in the state of maximum entropy for a significant time span that depends on the initial energy of the radiation field.

47 CFR 65.102 - Petitions for exclusion from unitary treatment and for individual treatment in determining...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Petitions for exclusion from unitary treatment and for individual treatment in determining authorized return for interstate exchange access service. 65.102 Section 65.102 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERSTATE RATE OF RETURN...

Nonunitary and unitary approach to Eigenvalue problem of Boson operators and squeezed coherent states

NASA Technical Reports Server (NTRS)

Wunsche, A.

1993-01-01

The eigenvalue problem of the operator a + zeta(boson creation operator) is solved for arbitrarily complex zeta by applying a nonunitary operator to the vacuum state. This nonunitary approach is compared with the unitary approach leading for the absolute value of zeta less than 1 to squeezed coherent states.

Piaget's Egocentrism: A Unitary Construct?

ERIC Educational Resources Information Center

Ruthven, Avis J.; Cunningham, William L.

In order to determine whether egocentrism can be conceptualized as a unitary construct, 100 children (51 four-year-olds, 37 five-year-olds, and 12 six-year-olds) were administered a visual/spatial perspective task, a cognitive/communicative task, and an affective task. All tasks were designed to measure different facets of egocentrism. The 50…

Recasting Communication Theory and Research: A Cybernetic Approach.

ERIC Educational Resources Information Center

Hill, Gary A.

The author's main concern is to provide a research format which will supply a unitary conception of communication. The wide range of complex topics and variety of concepts embraced by communication theory and the rather disparate set of phenomena encompassed by communication research create this need for a unitary study approach capable of linking…

Arbitrary unitary transformations on optical states using a quantum memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Geoff T.; Pinel, Olivier; Hosseini, Mahdi

2014-12-04

We show that optical memories arranged along an optical path can perform arbitrary unitary transformations on frequency domain optical states. The protocol offers favourable scaling and can be used with any quantum memory that uses an off-resonant Raman transition to reversibly transfer optical information to an atomic spin coherence.

Matching relations for optimal entanglement concentration and purification

PubMed Central

Kong, Fan-Zhen; Xia, Hui-Zhi; Yang, Ming; Yang, Qing; Cao, Zhuo-Liang

2016-01-01

The bilateral controlled NOT (CNOT) operation plays a key role in standard entanglement purification process, but the CNOT operation may not be the optimal joint operation in the sense that the output entanglement is maximized. In this paper, the CNOT operations in both the Schmidt-projection based entanglement concentration and the entanglement purification schemes are replaced with a general joint unitary operation, and the optimal matching relations between the entangling power of the joint unitary operation and the non-maximal entangled channel are found for optimizing the entanglement in- crement or the output entanglement. The result is somewhat counter-intuitive for entanglement concentration. The output entanglement is maximized when the entangling power of the joint unitary operation and the quantum channel satisfy certain relation. There exist a variety of joint operations with non-maximal entangling power that can induce a maximal output entanglement, which will greatly broaden the set of the potential joint operations in entanglement concentration. In addition, the entanglement increment in purification process is maximized only by the joint unitary operations (including CNOT) with maximal entangling power. PMID:27189800

Maximum saliency bias in binocular fusion

NASA Astrophysics Data System (ADS)

Lu, Yuhao; Stafford, Tom; Fox, Charles

2016-07-01

Subjective experience at any instant consists of a single ("unitary"), coherent interpretation of sense data rather than a "Bayesian blur" of alternatives. However, computation of Bayes-optimal actions has no role for unitary perception, instead being required to integrate over every possible action-percept pair to maximise expected utility. So what is the role of unitary coherent percepts, and how are they computed? Recent work provided objective evidence for non-Bayes-optimal, unitary coherent, perception and action in humans; and further suggested that the percept selected is not the maximum a posteriori percept but is instead affected by utility. The present study uses a binocular fusion task first to reproduce the same effect in a new domain, and second, to test multiple hypotheses about exactly how utility may affect the percept. After accounting for high experimental noise, it finds that both Bayes optimality (maximise expected utility) and the previously proposed maximum-utility hypothesis are outperformed in fitting the data by a modified maximum-salience hypothesis, using unsigned utility magnitudes in place of signed utilities in the bias function.

Identification and analysis of unitary loss of long-established protein-coding genes in Poaceae shows evidences for biased gene loss and putatively functional transcription of relics.

PubMed

Zhao, Yi; Tang, Liang; Li, Zhe; Jin, Jinpu; Luo, Jingchu; Gao, Ge

2015-04-18

Long-established protein-coding genes may lose their coding potential during evolution ("unitary gene loss"). Members of the Poaceae family are a major food source and represent an ideal model clade for plant evolution research. However, the global pattern of unitary gene loss in Poaceae genomes as well as the evolutionary fate of lost genes are still less-investigated and remain largely elusive. Using a locally developed pipeline, we identified 129 unitary gene loss events for long-established protein-coding genes from four representative species of Poaceae, i.e. brachypodium, rice, sorghum and maize. Functional annotation suggested that the lost genes in all or most of Poaceae species are enriched for genes involved in development and response to endogenous stimulus. We also found that 44 mutated genomic loci of lost genes, which we referred as relics, were still actively transcribed, and of which 84% (37 of 44) showed significantly differential expression across different tissues. More interestingly, we found that there were totally five expressed relics may function as competitive endogenous RNA in brachypodium, rice and sorghum genome. Based on comparative genomics and transcriptome data, we firstly compiled a comprehensive catalogue of unitary gene loss events in Poaceae species and characterized a statistically significant functional preference for these lost genes as well showed the potential of relics functioning as competitive endogenous RNAs in Poaceae genomes.

The canonical quantization of chaotic maps on the torus

NASA Astrophysics Data System (ADS)

Rubin, Ron Shai

In this thesis, a quantization method for classical maps on the torus is presented. The quantum algebra of observables is defined as the quantization of measurable functions on the torus with generators exp (2/pi ix) and exp (2/pi ip). The Hilbert space we use remains the infinite-dimensional L2/ (/IR, dx). The dynamics is given by a unitary quantum propagator such that as /hbar /to 0, the classical dynamics is returned. We construct such a quantization for the Kronecker map, the cat map, the baker's map, the kick map, and the Harper map. For the cat map, we find the same for the propagator on the plane the same integral kernel conjectured in (HB) using semiclassical methods. We also define a quantum 'integral over phase space' as a trace over the quantum algebra. Using this definition, we proceed to define quantum ergodicity and mixing for maps on the torus. We prove that the quantum cat map and Kronecker map are both ergodic, but only the cat map is mixing, true to its classical origins. For Planck's constant satisfying the integrality condition h = 1/N, with N/in doubz+, we construct an explicit isomorphism between L2/ (/IR, dx) and the Hilbert space of sections of an N-dimensional vector bundle over a θ-torus T2 of boundary conditions. The basis functions are distributions in L2/ (/IR, dx), given by an infinite comb of Dirac δ-functions. In Bargmann space these distributions take on the form of Jacobi ϑ-functions. Transformations from position to momentum representation can be implemented via a finite N-dimensional discrete Fourier transform. With the θ-torus, we provide a connection between the finite-dimensional quantum maps given in the physics literature and the canonical quantization presented here and found in the language of pseudo-differential operators elsewhere in mathematics circles. Specifically, at a fixed point of the dynamics on the θ-torus, we return a finite-dimensional matrix propagator. We present this connection explicitly for several examples.

Dissociable effects of reward and expectancy during evaluative feedback processing revealed by topographic ERP mapping analysis.

PubMed

Gheza, Davide; Paul, Katharina; Pourtois, Gilles

2017-11-24

Evaluative feedback provided during performance monitoring (PM) elicits either a positive or negative deflection ~250-300ms after its onset in the event-related potential (ERP) depending on whether the outcome is reward-related or not, as well as expected or not. However, it remains currently unclear whether these two deflections reflect a unitary process, or rather dissociable effects arising from non-overlapping brain networks. To address this question, we recorded 64-channel EEG in healthy adult participants performing a standard gambling task where valence and expectancy were manipulated in a factorial design. We analyzed the feedback-locked ERP data using a conventional ERP analysis, as well as an advanced topographic ERP mapping analysis supplemented with distributed source localization. Results reveal two main topographies showing opposing valence effects, and being differently modulated by expectancy. The first one was short-lived and sensitive to no-reward irrespective of expectancy. Source-estimation associated with this topographic map comprised mainly regions of the dorsal anterior cingulate cortex. The second one was primarily driven by reward, had a prolonged time-course and was monotonically influenced by expectancy. Moreover, this reward-related topographical map was best accounted for by intracranial generators estimated in the posterior cingulate cortex. These new findings suggest the existence of dissociable brain systems depending on feedback valence and expectancy. More generally, they inform about the added value of using topographic ERP mapping methods, besides conventional ERP measurements, to characterize qualitative changes occurring in the spatio-temporal dynamic of reward processing during PM. Copyright © 2017 Elsevier B.V. All rights reserved.

Global-local feature attention network with reranking strategy for image caption generation

NASA Astrophysics Data System (ADS)

Wu, Jie; Xie, Si-ya; Shi, Xin-bao; Chen, Yao-wen

2017-11-01

In this paper, a novel framework, named as global-local feature attention network with reranking strategy (GLAN-RS), is presented for image captioning task. Rather than only adopting unitary visual information in the classical models, GLAN-RS explores the attention mechanism to capture local convolutional salient image maps. Furthermore, we adopt reranking strategy to adjust the priority of the candidate captions and select the best one. The proposed model is verified using the Microsoft Common Objects in Context (MSCOCO) benchmark dataset across seven standard evaluation metrics. Experimental results show that GLAN-RS significantly outperforms the state-of-the-art approaches, such as multimodal recurrent neural network (MRNN) and Google NIC, which gets an improvement of 20% in terms of BLEU4 score and 13 points in terms of CIDER score.

Investigation of electronic transport through a ladder-like graphene nanoribbon including random distributed impurities

NASA Astrophysics Data System (ADS)

Esmaili, Esmat; Mardaani, Mohammad; Rabani, Hassan

2018-01-01

The electronic transport of a ladder-like graphene nanoribbon which the on-site or hopping energies of a small part of it can be random is modeled by using the Green's function technique within the nearest neighbor tight-binding approach. We employ a unitary transformation in order to convert the Hamiltonian of the nanoribbon to the Hamiltonian of a tight-binding ladder-like network. In this case, the disturbed part of the system includes the second neighbor hopping interactions. While, the converted Hamiltonian of each ideal part is equivalent to the Hamiltonian of two periodic on-site chains. Therefore, we can insert the self-energies of the alternative on-site tight-binding chains to the inverse of the Green's function matrix of the ladder-like part. In this viewpoint, the conductance is constructed from two trans and cis contributions. The results show that increasing the disorder strength causes the increase and decrease of the conductance of the trans and cis contributions, respectively.

On the mapping associated with the complex representation of functions and processes.

NASA Technical Reports Server (NTRS)

Harger, R. O.

1972-01-01

The mapping between function spaces that is implied by the representation of a real 'bandpass' function by a complex 'low-pass' function is explicitly accepted. The discussion is extended to the representation of stationary random processes where the mapping is between spaces of random processes. This approach clarifies the nature of the complex representation, especially in the case of random processes and, in addition, derives the properties of the complex representation.-

A Stochastic Simulation Framework for the Prediction of Strategic Noise Mapping and Occupational Noise Exposure Using the Random Walk Approach

PubMed Central

Haron, Zaiton; Bakar, Suhaimi Abu; Dimon, Mohamad Ngasri

2015-01-01

Strategic noise mapping provides important information for noise impact assessment and noise abatement. However, producing reliable strategic noise mapping in a dynamic, complex working environment is difficult. This study proposes the implementation of the random walk approach as a new stochastic technique to simulate noise mapping and to predict the noise exposure level in a workplace. A stochastic simulation framework and software, namely RW-eNMS, were developed to facilitate the random walk approach in noise mapping prediction. This framework considers the randomness and complexity of machinery operation and noise emission levels. Also, it assesses the impact of noise on the workers and the surrounding environment. For data validation, three case studies were conducted to check the accuracy of the prediction data and to determine the efficiency and effectiveness of this approach. The results showed high accuracy of prediction results together with a majority of absolute differences of less than 2 dBA; also, the predicted noise doses were mostly in the range of measurement. Therefore, the random walk approach was effective in dealing with environmental noises. It could predict strategic noise mapping to facilitate noise monitoring and noise control in the workplaces. PMID:25875019

Mixing rates and limit theorems for random intermittent maps

NASA Astrophysics Data System (ADS)

Bahsoun, Wael; Bose, Christopher

2016-04-01

We study random transformations built from intermittent maps on the unit interval that share a common neutral fixed point. We focus mainly on random selections of Pomeu-Manneville-type maps {{T}α} using the full parameter range 0<α <∞ , in general. We derive a number of results around a common theme that illustrates in detail how the constituent map that is fastest mixing (i.e. smallest α) combined with details of the randomizing process, determines the asymptotic properties of the random transformation. Our key result (theorem 1.1) establishes sharp estimates on the position of return time intervals for the quenched dynamics. The main applications of this estimate are to limit laws (in particular, CLT and stable laws, depending on the parameters chosen in the range 0<α <1 ) for the associated skew product; these are detailed in theorem 3.2. Since our estimates in theorem 1.1 also hold for 1≤slant α <∞ we study a second class of random transformations derived from piecewise affine Gaspard-Wang maps, prove existence of an infinite (σ-finite) invariant measure and study the corresponding correlation asymptotics. To the best of our knowledge, this latter kind of result is completely new in the setting of random transformations.

Indefinite intertwining operators

PubMed Central

Baldoni-Silva, M. W.; Knapp, A. W.

1984-01-01

For a wide class of linear connected semisimple Lie groups, one obtains formulas limiting the Langlands parameters of irreducible unitary representations obtained from maximal parabolic subgroups. The formulas relate unitarity to the number of roots satisfying certain conditions. Some evidence is presented that the formulas are sharp. The results confirm aspects of conjectures that relate unitary parameters to cohomological induction. PMID:16593424

Unitary Plan Wind Tunnel Landmark Dedication and Revitalization

NASA Technical Reports Server (NTRS)

1990-01-01

This video shows construction scenes of unitary plan wind tunnel, aerials, and views of various models, including an MD-II in the 11 ft, an Apollo in the 8x7, Dynasoar in the 8x7, a one inch scale shuttle in the 8x7, and an artist's concept of a 12 ft test section.

Entanglement classes of symmetric Werner states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyons, David W.; Walck, Scott N.

2011-10-15

The symmetric Werner states for n qubits, important in the study of quantum nonlocality and useful for applications in quantum information, have a surprisingly simple and elegant structure in terms of tensor products of Pauli matrices. Further, each of these states forms a unique local unitary equivalence class, that is, no two of these states are interconvertible by local unitary operations.

A Quantitative Analysis of the Increase in Public School Segregation in Delaware: 1989-2006

ERIC Educational Resources Information Center

Glenn, William J.

2011-01-01

This study analyzes the increase in school segregation in Delaware from a quantitative perspective. The article tests the hypothesis that the declaration of unitary status that released the Wilmington area school districts from their desegregation order caused the increase in segregation. The research reveals that the declaration of unitary status…

An answer to Housing Discrimination: The Need for a Unitary Marketing System

ERIC Educational Resources Information Center

Rosser, Lawrence; White, Beth

1975-01-01

Proposes that a central Clearinghouse be established to collect and disseminate information to inner city residents on available suburban units, noting that to be effective, this unitary marketing system would have to be able to identify and seek out those who most need rental vacancy data, and to deliver vacancy listings and related information…

Beyond the Tipping Point: Issues of Racial Diversity in Magnet Schools Following Unitary Status

ERIC Educational Resources Information Center

Smrekar, Claire

2009-01-01

This article uses qualitative case study methodology to examine why the racial composition of magnet schools in Nashville, Tennessee, has shifted to predominantly African American in the aftermath of unitary status. The article compares the policy contexts and parents' reasons for choosing magnet schools at two points in time--under court order…

Stability issues of black hole in non-local gravity

NASA Astrophysics Data System (ADS)

Myung, Yun Soo; Park, Young-Jai

2018-04-01

We discuss stability issues of Schwarzschild black hole in non-local gravity. It is shown that the stability analysis of black hole for the unitary and renormalizable non-local gravity with γ2 = - 2γ0 cannot be performed in the Lichnerowicz operator approach. On the other hand, for the unitary and non-renormalizable case with γ2 = 0, the black hole is stable against the metric perturbations. For non-unitary and renormalizable local gravity with γ2 = - 2γ0 = const (fourth-order gravity), the small black holes are unstable against the metric perturbations. This implies that what makes the problem difficult in stability analysis of black hole is the simultaneous requirement of unitarity and renormalizability around the Minkowski spacetime.

Single-qubit unitary gates by graph scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumer, Benjamin A.; Underwood, Michael S.; Feder, David L.

2011-12-15

We consider the effects of plane-wave states scattering off finite graphs as an approach to implementing single-qubit unitary operations within the continuous-time quantum walk framework of universal quantum computation. Four semi-infinite tails are attached at arbitrary points of a given graph, representing the input and output registers of a single qubit. For a range of momentum eigenstates, we enumerate all of the graphs with up to n=9 vertices for which the scattering implements a single-qubit gate. As n increases, the number of new unitary operations increases exponentially, and for n>6 the majority correspond to rotations about axes distributed roughly uniformlymore » across the Bloch sphere. Rotations by both rational and irrational multiples of {pi} are found.« less

The random continued fraction transformation

NASA Astrophysics Data System (ADS)

Kalle, Charlene; Kempton, Tom; Verbitskiy, Evgeny

2017-03-01

We introduce a random dynamical system related to continued fraction expansions. It uses random combinations of the Gauss map and the Rényi (or backwards) continued fraction map. We explore the continued fraction expansions that this system produces, as well as the dynamical properties of the system.

Pseudo-Random Number Generator Based on Coupled Map Lattices

NASA Astrophysics Data System (ADS)

Lü, Huaping; Wang, Shihong; Hu, Gang

A one-way coupled chaotic map lattice is used for generating pseudo-random numbers. It is shown that with suitable cooperative applications of both chaotic and conventional approaches, the output of the spatiotemporally chaotic system can easily meet the practical requirements of random numbers, i.e., excellent random statistical properties, long periodicity of computer realizations, and fast speed of random number generations. This pseudo-random number generator system can be used as ideal synchronous and self-synchronizing stream cipher systems for secure communications.

May a unitary autonomic index help assess autonomic cardiac regulation in elite athletes? Preliminary observations on the national Italian Olympic committee team.

PubMed

Sala, Roberto; Malacarne, Mara; Tosi, Fabio; Benzi, Manuela; Solaro, Nadia; Tamorri, Stefano; Spataro, Antonio; Pagani, Massimo; Lucini, Daniela

2017-12-01

Long term endurance training, as occurring in elite athletes, is associated to cardiac neural remodeling in favor of cardioprotective vagal mechanisms, resulting in resting bradycardia and augmented contribution of cardiac parasympathetic nerve activity. Autonomic assessment can be performed by way of heart rate variability. This technique however provides multiple indices, and there is not yet complete agreement on their specific significance. Purpose of the study was to assess whether a rank transformation and radar plot could provide a unitary autonomic index, capable to show a correlation between intensity of individual work and quality of autonomic regulation. We studied 711 (23.6±6.2 years) elite athletes that took part in the selection procedure for the 2016 Rio Olympic Games for the National Italian Olympic Committee (CONI). Indices from Heart Rate Variability HRV obtained at rest, during standing up and during recovery from an exercise test were used to compute a percent ranked unitary autonomic index for sport (ANSIs), taken as proxy of quality of autonomic regulation. Within the observed wide range of energy expenditure, the unitary autonomic index ANSIs appears significantly correlated to individual and discipline specific training workloads (r=0.25, P<0.001 and r=0.78, P<0.001, respectively), correcting for possible age and gender bias. ANSIs also positively correlates to lipid profile. Estimated intensity of physical activity correlates with quality of cardiac autonomic regulation, as expressed by a novel unitary index of cardiac autonomic regulation. ANSIs could provide a novel and convenient approach to individual autonomic evaluation in athletes.

Cognitive Load in Percentage Change Problems: Unitary, Pictorial, and Equation Approaches to Instruction

ERIC Educational Resources Information Center

Ngu, Bing Hiong; Yeung, Alexander Seeshing; Tobias, Stephen

2014-01-01

Eighth grade students in Australia (N = 60) participated in an experiment on learning how to solve percentage change problems in a regular classroom in three conditions: unitary, pictorial, and equation approaches. The procedure involved a pre-test, an acquisition phase, and a post-test. The main goal was to test the relative merits of the three…

Discourses in Reading and Linguistics. Annals of the New York Academy of Sciences, Volume 433.

ERIC Educational Resources Information Center

White, Sheila J., Ed.; Teller, Virginia, Ed.

That the attainment of literacy does not represent a unitary process or a unitary set of skills is reflected in this collection of papers from a variety of disciplines showing concerns about reading problems. Following an introduction by Sheila White, the first half of the book contains the following articles: "The Practice of Literacy: Where Mind…

Reproducible, high performance patch antenna array apparatus and method of fabrication

DOEpatents

Strassner, II, Bernd H.

2007-01-23

A reproducible, high-performance patch antenna array apparatus includes a patch antenna array provided on a unitary dielectric substrate, and a feed network provided on the same unitary substrate and proximity coupled to the patch antenna array. The reproducibility is enhanced by using photolithographic patterning and etching to produce both the patch antenna array and the feed network.

Parallel and pipeline computation of fast unitary transforms

NASA Technical Reports Server (NTRS)

Fino, B. J.; Algazi, V. R.

1975-01-01

The letter discusses the parallel and pipeline organization of fast-unitary-transform algorithms such as the fast Fourier transform, and points out the efficiency of a combined parallel-pipeline processor of a transform such as the Haar transform, in which (2 to the n-th power) -1 hardware 'butterflies' generate a transform of order 2 to the n-th power every computation cycle.

Quantum tomography of near-unitary processes in high-dimensional quantum systems

NASA Astrophysics Data System (ADS)

Lysne, Nathan; Sosa Martinez, Hector; Jessen, Poul; Baldwin, Charles; Kalev, Amir; Deutsch, Ivan

2016-05-01

Quantum Tomography (QT) is often considered the ideal tool for experimental debugging of quantum devices, capable of delivering complete information about quantum states (QST) or processes (QPT). In practice, the protocols used for QT are resource intensive and scale poorly with system size. In this situation, a well behaved model system with access to large state spaces (qudits) can serve as a useful platform for examining the tradeoffs between resource cost and accuracy inherent in QT. In past years we have developed one such experimental testbed, consisting of the electron-nuclear spins in the electronic ground state of individual Cs atoms. Our available toolkit includes high fidelity state preparation, complete unitary control, arbitrary orthogonal measurements, and accurate and efficient QST in Hilbert space dimensions up to d = 16. Using these tools, we have recently completed a comprehensive study of QPT in 4, 7 and 16 dimensions. Our results show that QPT of near-unitary processes is quite feasible if one chooses optimal input states and efficient QST on the outputs. We further show that for unitary processes in high dimensional spaces, one can use informationally incomplete QPT to achieve high-fidelity process reconstruction (90% in d = 16) with greatly reduced resource requirements.

SU-E-T-365: Estimation of Neutron Ambient Dose Equivalents for Radioprotection Exposed Workers in Radiotherapy Facilities Based On Characterization Patient Risk Estimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Irazola, L; Terron, J; Sanchez-Doblado, F

2015-06-15

Purpose: Previous measurements with Bonner spheres{sup 1} showed that normalized neutron spectra are equal for the majority of the existing linacs{sup 2}. This information, in addition to thermal neutron fluences obtained in the characterization procedure{sup 3}3, would allow to estimate neutron doses accidentally received by exposed workers, without the need of an extra experimental measurement. Methods: Monte Carlo (MC) simulations demonstrated that the thermal neutron fluence distribution inside the bunker is quite uniform, as a consequence of multiple scatter in the walls{sup 4}. Although inverse square law is approximately valid for the fast component, a more precise calculation could bemore » obtained with a generic fast fluence distribution map around the linac, from MC simulations{sup 4}. Thus, measurements of thermal neutron fluences performed during the characterization procedure{sup 3}, together with a generic unitary spectra{sup 2}, would allow to estimate the total neutron fluences and H*(10) at any point{sup 5}. As an example, we compared estimations with Bonner sphere measurements{sup 1}, for two points in five facilities: 3 Siemens (15–23 MV), Elekta (15 MV) and Varian (15 MV). Results: Thermal neutron fluences obtained from characterization, are within (0.2–1.6×10{sup 6}) cm−{sup 2}•Gy{sup −1} for the five studied facilities. This implies ambient equivalent doses ranging from (0.27–2.01) mSv/Gy 50 cm far from the isocenter and (0.03–0.26) mSv/Gy at detector location with an average deviation of ±12.1% respect to Bonner measurements. Conclusion: The good results obtained demonstrate that neutron fluence and H*(10) can be estimated based on: (a) characterization procedure established for patient risk estimation in each facility, (b) generic unitary neutron spectrum and (c) generic MC map distribution of the fast component. [1] Radiat. Meas (2010) 45: 1391 – 1397; [2] Phys. Med. Biol (2012) 5 7:6167–6191; [3] Med. Phys (2015) 42:276 - 281. [4] IFMBE (2012) 39: 1245–1248. [5] ICRU Report 57 (1998)« less

Stepwise emergence of the face-sensitive N170 event-related potential component.

PubMed

Jemel, Boutheina; Schuller, Anne-Marie; Cheref-Khan, Yasémine; Goffaux, Valérie; Crommelinck, Marc; Bruyer, Raymond

2003-11-14

The present study used a parametric design to characterize early event-related potentials (ERP) to face stimuli embedded in gradually decreasing random noise levels. For both N170 and the vertex positive potential (VPP) there was a linear increase in amplitude and decrease in latency with decreasing levels of noise. In contrast, the earlier visual P1 component was stable across noise levels. The P1/N170 dissociation suggests not only a functional dissociation between low and high-level visual processing of faces but also that the N170 reflects the integration of sensorial information into a unitary representation. In addition, the N170/VPP association supports the view that they reflect the same processes operating when viewing faces.

Observability of market daily volatility

NASA Astrophysics Data System (ADS)

Petroni, Filippo; Serva, Maurizio

2016-02-01

We study the price dynamics of 65 stocks from the Dow Jones Composite Average from 1973 to 2014. We show that it is possible to define a Daily Market Volatility σ(t) which is directly observable from data. This quantity is usually indirectly defined by r(t) = σ(t) ω(t) where the r(t) are the daily returns of the market index and the ω(t) are i.i.d. random variables with vanishing average and unitary variance. The relation r(t) = σ(t) ω(t) alone is unable to give an operative definition of the index volatility, which remains unobservable. On the contrary, we show that using the whole information available in the market, the index volatility can be operatively defined and detected.

INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Efficient One-Step Generation of Cluster State with Charge Qubits in Circuit QED

NASA Astrophysics Data System (ADS)

Wang, Yi-Min; Li, Cheng-Zu

2010-01-01

We propose theoretical schemes to generate highly entangled cluster state with superconducting qubits in a circuit QED architecture. Charge qubits are located inside a superconducting transmission line, which serves as a quantum data bus. We show that large clusters state can be efficiently generated in just one step with the long-range Ising-like unitary operators. The quantum operations which are generally realized by two coupling mechanisms: either voltage coupling or current coupling, depend only on global geometric features and are insensitive not only to the thermal state of the transmission line but also to certain random operation errors. Thus high-fidelity one-way quantum computation can be achieved.

Fault detection and bypass in a sequence information signal processor

NASA Technical Reports Server (NTRS)

Peterson, John C. (Inventor); Chow, Edward T. (Inventor)

1992-01-01

The invention comprises a plurality of scan registers, each such register respectively associated with a processor element; an on-chip comparator, encoder and fault bypass register. Each scan register generates a unitary signal the logic state of which depends on the correctness of the input from the previous processor in the systolic array. These unitary signals are input to a common comparator which generates an output indicating whether or not an error has occurred. These unitary signals are also input to an encoder which identifies the location of any fault detected so that an appropriate multiplexer can be switched to bypass the faulty processor element. Input scan data can be readily programmed to fully exercise all of the processor elements so that no fault can remain undetected.

Stability of a Unitary Bose Gas

NASA Astrophysics Data System (ADS)

Fletcher, Richard J.; Gaunt, Alexander L.; Navon, Nir; Smith, Robert P.; Hadzibabic, Zoran

2013-09-01

We study the stability of a thermal K39 Bose gas across a broad Feshbach resonance, focusing on the unitary regime, where the scattering length a exceeds the thermal wavelength λ. We measure the general scaling laws relating the particle-loss and heating rates to the temperature, scattering length, and atom number. Both at unitarity and for positive a≪λ we find agreement with three-body theory. However, for a<0 and away from unitarity, we observe significant four-body decay. At unitarity, the three-body loss coefficient, L3∝λ4, is 3 times lower than the universal theoretical upper bound. This reduction is a consequence of species-specific Efimov physics and makes K39 particularly promising for studies of many-body physics in a unitary Bose gas.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikolić, Hrvoje, E-mail: hnikolic@irb.hr

An argument by Banks, Susskind and Peskin (BSP), according to which violation of unitarity would violate either locality or energy-momentum conservation, is widely believed to be a strong argument against non-unitarity of Hawking radiation. We find that the whole BSP argument rests on the crucial assumption that the Hamiltonian is not highly degenerate, and point out that this assumption is not satisfied for systems with many degrees of freedom. Using Lindblad equation, we show that high degeneracy of the Hamiltonian allows local non-unitary evolution without violating energy-momentum conservation. Moreover, since energy-momentum is the source of gravity, we argue that energy-momentummore » is necessarily conserved for a large class of non-unitary systems with gravity. Finally, we explicitly calculate the Lindblad operators for non-unitary Hawking radiation and show that they conserve energy-momentum.« less

Supersonic Retropropulsion Test 1853 in NASA LaRC Unitary Plan Wind Tunnel Test Section 2

NASA Technical Reports Server (NTRS)

Berry, Scott A.; Rhode, Matthew N.

2014-01-01

A supersonic retropropulsion experiment was conducted in the Langley Research Center Unitary Plan Wind Tunnel Test Section 2 at Mach numbers of 2.4, 3.5, and 4.6. Intended as a code validation effort, this study used pretest computations to size and refine the model such that tunnel blockage and internal flow separations were minimized. A 5-in diameter 70 degree sphere-cone forebody, which can accommodate up to four 4:1 area ratio nozzles, followed by a 9.55 inches long cylindrical aft body was selected for this test after computational maturation. The primary measurements for this experiment were high spatial-density surface pressures. In addition, high speed schlieren video and internal pressures and temperatures were acquired. The test included parametric variations in the number of nozzles utilized, thrust coefficients (roughly 0 to 4), and angles of attack (-8 to 20 degrees). The run matrix was developed to also allow quantification of various sources of experimental uncertainty, such as random errors due to run-to-run variations and systematic errors due to flowfield or model misalignments. To accommodate the uncertainty assessment, many runs and replicates were conducted with the model at various locations within the tunnel and with model roll angles of 0, 60, 120, and 180 degrees. This test report provides operational details of the experiment, contains a review of trends, and provides all schlieren and pressure results within appendices.

Assessment of the Emerging Biocruise Threat

DTIC Science & Technology

2000-08-01

navigation and guidance system is located in the front; and the fuel and warhead are typically located in the midbody .66 (See Figure 1.) Guidance of a...unitary or submunitions Undetermined Undetermined MUPSOW South Africa Air & ground Conventional/ unitary or submunitions 200+ 2002 Storm Shadow ...replicating agents, bacteria or viruses, or nonreplicating materials, toxins or physiologically active proteins or peptides, that can be produced by living

A note on parallel and pipeline computation of fast unitary transforms

NASA Technical Reports Server (NTRS)

Fino, B. J.; Algazi, V. R.

1974-01-01

The parallel and pipeline organization of fast unitary transform algorithms such as the Fast Fourier Transform are discussed. The efficiency is pointed out of a combined parallel-pipeline processor of a transform such as the Haar transform in which 2 to the n minus 1 power hardware butterflies generate a transform of order 2 to the n power every computation cycle.

On a constructive procedure for verifying whether a matrix can be made real by a unitary similarity transformation

NASA Astrophysics Data System (ADS)

Ikramov, Kh. D.

2010-03-01

There are well-known conditions under which a complex n × n matrix A can be made real by a similarity transformation. Under the additional assumption that A has a simple real spectrum, a constructive answer is given to the question whether this transformation can be realized via a unitary rather than arbitrary similarity.

Unitary synaptic connections among substantia nigra pars reticulata neurons

PubMed Central

Wilson, Charles J.

2016-01-01

Neurons in substantia nigra pars reticulata (SNr) are synaptically coupled by local axon collaterals, providing a potential mechanism for local signal processing. Because SNr neurons fire spontaneously, these synapses are constantly active. To investigate their properties, we recorded spontaneous inhibitory postsynaptic currents (sIPSCs) from SNr neurons in brain slices, in which afferents from upstream nuclei are severed, and the cells fire rhythmically. The sIPSC trains contained a mixture of periodic and aperiodic events. Autocorrelation analysis of sIPSC trains showed that a majority of cells had one to four active unitary inputs. The properties of the unitary IPSCs (uIPSCs) were analyzed for cells with one unitary input, using a model of periodic presynaptic firing and stochastic synaptic transmission. The inferred presynaptic firing rates and coefficient of variation of interspike intervals (ISIs) corresponded well with direct measurements of spiking in SNr neurons. Methods were developed to estimate the success probability, amplitude distributions, and kinetics of the uIPSCs, while removing the contribution from aperiodic sIPSCs. The sIPSC amplitudes were not increased upon release from halorhodopsin silencing, suggesting that most synapses were not depressed at the spontaneous firing rate. Gramicidin perforated-patch recordings indicated that the average reversal potential of spontaneous inhibitory postsynaptic potentials was −64 mV. Because of the change in driving force across the ISI, the unitary inputs are predicted to have a larger postsynaptic impact when they arrive late in the ISI. Simulations of network activity suggest that this very sparse inhibitory coupling may act to desynchronize the activity of SNr neurons while having only a small effect on firing rate. PMID:26961101

Action-angle variables for the harmonic oscillator: Ambiguity spin × duplication spin

NASA Astrophysics Data System (ADS)

de Oliveira, César R.; Malta, Coraci P.

1984-07-01

The difficulties of obtaining for the harmonic oscillator a well-defined unitary transformation to action-angle variables were overcome by M. Moshinsky and T. H. Seligman ( Ann. Phys. (N.Y.)114 (1978), 243) through the introduction of a spinlike variable (ambiguity spin) from a classical point of view. The difficulty of defining a unitary phase operator for the harmonic oscillator was overcome by Roger G. Newton ( Ann. Phys. (N.Y.)124 (1980), 324) also through the introduction of a spinlike variable (named duplication spin by us) but within a quantum framework. Here the relation between the ambiguity spin and the duplication spin is investigated by introducing these two types of spins in the canonical transformation to action-angle variables. In this way both well-defined unitary transformation and phase operators were obtained.

Generalized graphs and unitary irrational central charge in the superconformal master equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halpern, M.B.; Obers, N.A.

1991-12-01

For each magic basis of Lie {ital g}, it is known that the Virasoro master equation on affine {ital g} contains a generalized graph theory of conformal level-families. In this paper, it is found that the superconformal master equation on affine {ital g}{times}SO(dim {ital g}) similarly contains a generalized graph theory of superconformal level-families for each magic basis of {ital g}. The superconformal level-families satisfy linear equations on the generalized graphs, and the first exact unitary irrational solutions of the superconformal master equation are obtained on the sine-area graphs of {ital g}=SU({ital n}), including the simplest unitary irrational central chargesmore » {ital c}=6{ital nx}/({ital nx}+8 sin{sup 2}(rs{pi}/n)) yet observed in the program.« less

No chiral truncation of quantum log gravity?

NASA Astrophysics Data System (ADS)

Andrade, Tomás; Marolf, Donald

2010-03-01

At the classical level, chiral gravity may be constructed as a consistent truncation of a larger theory called log gravity by requiring that left-moving charges vanish. In turn, log gravity is the limit of topologically massive gravity (TMG) at a special value of the coupling (the chiral point). We study the situation at the level of linearized quantum fields, focussing on a unitary quantization. While the TMG Hilbert space is continuous at the chiral point, the left-moving Virasoro generators become ill-defined and cannot be used to define a chiral truncation. In a sense, the left-moving asymptotic symmetries are spontaneously broken at the chiral point. In contrast, in a non-unitary quantization of TMG, both the Hilbert space and charges are continuous at the chiral point and define a unitary theory of chiral gravity at the linearized level.

The contact of a homogeneous unitary Fermi gas

NASA Astrophysics Data System (ADS)

Mukherjee, Biswaroop; Patel, Parth; Yan, Zhenjie; Fletcher, Richard; Struck, Julian; Zwierlein, Martin

2017-04-01

The contact is a fundamental quantity that measures the strength of short-range correlations in quantum gases. As one of its most important implications, it provides a link between the microscopic two-particle correlation function at small distance and the macroscopic thermodynamic properties of the gas. In particular, pairing and superfluidity in a unitary Fermi gas can be expected to leave its mark in behavior of the contact. Here we present measurements on the temperature dependence of the contact of a unitary Fermi gas across the superfluid transition. By trapping ultracold 6Li atoms in a potential that is homogeneous in two directions and harmonic in the third, we obtain radiofrequency spectra of the homogeneous gas at a high signal-to-noise ratio. We compare our data to existing, but often mutually excluding theoretical calculations for the strongly interacting Fermi gas.

Variations on a theme of Lander and Waterman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speed, T.

1997-12-01

The original Lander and Waterman mathematical analysis was for fingerprinting random clones. Since that time, a number of variants of their theory have appeared, including ones which apply to mapping by anchoring random clones, and to non-random or directed clone mapping. The same theory is now widely used to devise random sequencing strategies. In this talk I will review these developments, and go on the discuss the theory required for directed sequencing strategies.

Unitary-matrix models as exactly solvable string theories

NASA Technical Reports Server (NTRS)

Periwal, Vipul; Shevitz, Danny

1990-01-01

Exact differential equations are presently found for the scaling functions of models of unitary matrices which are solved in a double-scaling limit, using orthogonal polynomials on a circle. For the case of the simplest, k = 1 model, the Painleve II equation with constant 0 is obtained; possible nonperturbative phase transitions exist for these models. Equations are presented for k = 2 and 3, and discussed with a view to asymptotic behavior.

Crypto-Unitary Forms of Quantum Evolution Operators

NASA Astrophysics Data System (ADS)

Znojil, Miloslav

2013-06-01

The description of quantum evolution using unitary operator {u}(t)=exp(-i{h}t) requires that the underlying self-adjoint quantum Hamiltonian {h} remains time-independent. In a way extending the so called {PT}-symmetric quantum mechanics to the models with manifestly time-dependent "charge" {C}(t) we propose and describe an extension of such an exponential-operator approach to evolution to the manifestly time-dependent self-adjoint quantum Hamiltonians {h}(t).

Optimal superdense coding over memory channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shadman, Z.; Kampermann, H.; Bruss, D.

2011-10-15

We study the superdense coding capacity in the presence of quantum channels with correlated noise. We investigate both the cases of unitary and nonunitary encoding. Pauli channels for arbitrary dimensions are treated explicitly. The superdense coding capacity for some special channels and resource states is derived for unitary encoding. We also provide an example of a memory channel where nonunitary encoding leads to an improvement in the superdense coding capacity.

Biophysically based mathematical modeling of interstitial cells of Cajal slow wave activity generated from a discrete unitary potential basis.

PubMed

Faville, R A; Pullan, A J; Sanders, K M; Koh, S D; Lloyd, C M; Smith, N P

2009-06-17

Spontaneously rhythmic pacemaker activity produced by interstitial cells of Cajal (ICC) is the result of the entrainment of unitary potential depolarizations generated at intracellular sites termed pacemaker units. In this study, we present a mathematical modeling framework that quantitatively represents the transmembrane ion flows and intracellular Ca2+ dynamics from a single ICC operating over the physiological membrane potential range. The mathematical model presented here extends our recently developed biophysically based pacemaker unit modeling framework by including mechanisms necessary for coordinating unitary potential events, such as a T-Type Ca2+ current, Vm-dependent K+ currents, and global Ca2+ diffusion. Model simulations produce spontaneously rhythmic slow wave depolarizations with an amplitude of 65 mV at a frequency of 17.4 cpm. Our model predicts that activity at the spatial scale of the pacemaker unit is fundamental for ICC slow wave generation, and Ca2+ influx from activation of the T-Type Ca2+ current is required for unitary potential entrainment. These results suggest that intracellular Ca2+ levels, particularly in the region local to the mitochondria and endoplasmic reticulum, significantly influence pacing frequency and synchronization of pacemaker unit discharge. Moreover, numerical investigations show that our ICC model is capable of qualitatively replicating a wide range of experimental observations.

The electronic stopping powers and angular energy-loss dependence of helium and lithium ions in the silicon crystal

NASA Astrophysics Data System (ADS)

Mikšová, R.; Macková, A.; Malinský, P.

2017-09-01

We have measured the electronic stopping powers of helium and lithium ions in the channelling direction of the Si〈1 0 0〉 crystal. The energy range used (2.0-8.0 MeV) was changed by 200 and 400-keV steps. The ratio α between the channelling and random stopping powers was determined as a function of the angle for 2, 3 and 4 MeV 4He+ ions and for 3 and 6 MeV 7Li+,2+ ions. The measurements were carried out using the Rutherford backscattering spectrometry in the channelling mode (RBS-C) in a silicon-on-insulator material. The experimental channelling stopping-power values measured in the channelling direction were then discussed in the frame of the random energy stopping predictions calculated using SRIM-2013 code and the theoretical unitary convolution approximation (UCA) model. The experimental channelling stopping-power values decrease with increasing ion energy. The stopping-power difference between channelled and randomly moving ions increases with the enhanced initial ion energy. The ratio between the channelling and random ion stopping powers α as a function of the ion beam incoming angle for 2, 3 and 4 MeV He+ ions and for 3 and 6 MeV Li+,2+ ions was observed in the range 0.5-1.

Conditional Random Field-Based Offline Map Matching for Indoor Environments

PubMed Central

Bataineh, Safaa; Bahillo, Alfonso; Díez, Luis Enrique; Onieva, Enrique; Bataineh, Ikram

2016-01-01

In this paper, we present an offline map matching technique designed for indoor localization systems based on conditional random fields (CRF). The proposed algorithm can refine the results of existing indoor localization systems and match them with the map, using loose coupling between the existing localization system and the proposed map matching technique. The purpose of this research is to investigate the efficiency of using the CRF technique in offline map matching problems for different scenarios and parameters. The algorithm was applied to several real and simulated trajectories of different lengths. The results were then refined and matched with the map using the CRF algorithm. PMID:27537892

Conditional Random Field-Based Offline Map Matching for Indoor Environments.

PubMed

Bataineh, Safaa; Bahillo, Alfonso; Díez, Luis Enrique; Onieva, Enrique; Bataineh, Ikram

2016-08-16

In this paper, we present an offline map matching technique designed for indoor localization systems based on conditional random fields (CRF). The proposed algorithm can refine the results of existing indoor localization systems and match them with the map, using loose coupling between the existing localization system and the proposed map matching technique. The purpose of this research is to investigate the efficiency of using the CRF technique in offline map matching problems for different scenarios and parameters. The algorithm was applied to several real and simulated trajectories of different lengths. The results were then refined and matched with the map using the CRF algorithm.

The Effect of Map Boundary on Estimates of Landscape Resistance to Animal Movement

PubMed Central

Koen, Erin L.; Garroway, Colin J.; Wilson, Paul J.; Bowman, Jeff

2010-01-01

Background Artificial boundaries on a map occur when the map extent does not cover the entire area of study; edges on the map do not exist on the ground. These artificial boundaries might bias the results of animal dispersal models by creating artificial barriers to movement for model organisms where there are no barriers for real organisms. Here, we characterize the effects of artificial boundaries on calculations of landscape resistance to movement using circuit theory. We then propose and test a solution to artificially inflated resistance values whereby we place a buffer around the artificial boundary as a substitute for the true, but unknown, habitat. Methodology/Principal Findings We randomly assigned landscape resistance values to map cells in the buffer in proportion to their occurrence in the known map area. We used circuit theory to estimate landscape resistance to organism movement and gene flow, and compared the output across several scenarios: a habitat-quality map with artificial boundaries and no buffer, a map with a buffer composed of randomized habitat quality data, and a map with a buffer composed of the true habitat quality data. We tested the sensitivity of the randomized buffer to the possibility that the composition of the real but unknown buffer is biased toward high or low quality. We found that artificial boundaries result in an overestimate of landscape resistance. Conclusions/Significance Artificial map boundaries overestimate resistance values. We recommend the use of a buffer composed of randomized habitat data as a solution to this problem. We found that resistance estimated using the randomized buffer did not differ from estimates using the real data, even when the composition of the real data was varied. Our results may be relevant to those interested in employing Circuitscape software in landscape connectivity and landscape genetics studies. PMID:20668690

Firewalls from double purity

NASA Astrophysics Data System (ADS)

Bousso, Raphael

2013-10-01

The firewall paradox is often presented as arising from double entanglement, but I argue that more generally the paradox is double purity. Near-horizon modes are purified by the interior, in the infalling vacuum. Hence, they cannot also be pure alone, or in combination with any third system, as demanded by unitarity. This conflict arises independently of the Page time, for entangled and for pure states. It implies that identifications of Hilbert spaces cannot resolve the paradox. Traditional complementarity requires the unitary identification of infalling matter with a scrambled subsystem of the Hawking radiation. Extending this map to the infalling vacuum overdetermines the out-state. More general complementarity maps (“A=RB,” “ER=EPR”) necessarily fail when the near-horizon zone is pure. I argue that pure-zone states span the microcanonical ensemble, and that this suffices to make the horizon a special place. I advocate that the ability to detect the horizon locally, rather than the degree or probability of violence, is what makes firewalls problematic. Conversely, if the production of matter at the horizon can be dynamically understood and shown to be consistent, then firewalls do not constitute a violation of the equivalence principle.

Comparing the efficiency of digital and conventional soil mapping to predict soil types in a semi-arid region in Iran

NASA Astrophysics Data System (ADS)

Zeraatpisheh, Mojtaba; Ayoubi, Shamsollah; Jafari, Azam; Finke, Peter

2017-05-01

The efficiency of different digital and conventional soil mapping approaches to produce categorical maps of soil types is determined by cost, sample size, accuracy and the selected taxonomic level. The efficiency of digital and conventional soil mapping approaches was examined in the semi-arid region of Borujen, central Iran. This research aimed to (i) compare two digital soil mapping approaches including Multinomial logistic regression and random forest, with the conventional soil mapping approach at four soil taxonomic levels (order, suborder, great group and subgroup levels), (ii) validate the predicted soil maps by the same validation data set to determine the best method for producing the soil maps, and (iii) select the best soil taxonomic level by different approaches at three sample sizes (100, 80, and 60 point observations), in two scenarios with and without a geomorphology map as a spatial covariate. In most predicted maps, using both digital soil mapping approaches, the best results were obtained using the combination of terrain attributes and the geomorphology map, although differences between the scenarios with and without the geomorphology map were not significant. Employing the geomorphology map increased map purity and the Kappa index, and led to a decrease in the 'noisiness' of soil maps. Multinomial logistic regression had better performance at higher taxonomic levels (order and suborder levels); however, random forest showed better performance at lower taxonomic levels (great group and subgroup levels). Multinomial logistic regression was less sensitive than random forest to a decrease in the number of training observations. The conventional soil mapping method produced a map with larger minimum polygon size because of traditional cartographic criteria used to make the geological map 1:100,000 (on which the conventional soil mapping map was largely based). Likewise, conventional soil mapping map had also a larger average polygon size that resulted in a lower level of detail. Multinomial logistic regression at the order level (map purity of 0.80), random forest at the suborder (map purity of 0.72) and great group level (map purity of 0.60), and conventional soil mapping at the subgroup level (map purity of 0.48) produced the most accurate maps in the study area. The multinomial logistic regression method was identified as the most effective approach based on a combined index of map purity, map information content, and map production cost. The combined index also showed that smaller sample size led to a preference for the order level, while a larger sample size led to a preference for the great group level.

Methotrexate, Doxorubicin, and Cisplatin (MAP) Plus Maintenance Pegylated Interferon Alfa-2b Versus MAP Alone in Patients With Resectable High-Grade Osteosarcoma and Good Histologic Response to Preoperative MAP: First Results of the EURAMOS-1 Good Response Randomized Controlled Trial

PubMed Central

Bielack, Stefan S.; Smeland, Sigbjørn; Whelan, Jeremy S.; Marina, Neyssa; Jovic, Gordana; Hook, Jane M.; Krailo, Mark D.; Gebhardt, Mark; Pápai, Zsuzsanna; Meyer, James; Nadel, Helen; Randall, R. Lor; Deffenbaugh, Claudia; Nagarajan, Rajaram; Brennan, Bernadette; Letson, G. Douglas; Teot, Lisa A.; Goorin, Allen; Baumhoer, Daniel; Kager, Leo; Werner, Mathias; Lau, Ching C.; Sundby Hall, Kirsten; Gelderblom, Hans; Meyers, Paul; Gorlick, Richard; Windhager, Reinhard; Helmke, Knut; Eriksson, Mikael; Hoogerbrugge, Peter M.; Schomberg, Paula; Tunn, Per-Ulf; Kühne, Thomas; Jürgens, Heribert; van den Berg, Henk; Böhling, Tom; Picton, Susan; Renard, Marleen; Reichardt, Peter; Gerss, Joachim; Butterfass-Bahloul, Trude; Morris, Carol; Hogendoorn, Pancras C.W.; Seddon, Beatrice; Calaminus, Gabriele; Michelagnoli, Maria; Dhooge, Catharina; Sydes, Matthew R.; Bernstein, Mark

2015-01-01

Purpose EURAMOS-1, an international randomized controlled trial, investigated maintenance therapy with pegylated interferon alfa-2b (IFN-α-2b) in patients whose osteosarcoma showed good histologic response (good response) to induction chemotherapy. Patients and Methods At diagnosis, patients age ≤ 40 years with resectable high-grade osteosarcoma were registered. Eligibility after surgery for good response random assignment included ≥ two cycles of preoperative MAP (methotrexate, doxorubicin, and cisplatin), macroscopically complete surgery of primary tumor, < 10% viable tumor, and no disease progression. These patients were randomly assigned to four additional cycles MAP with or without IFN-α-2b (0.5 to 1.0 μg/kg per week subcutaneously, after chemotherapy until 2 years postregistration). Outcome measures were event-free survival (EFS; primary) and overall survival and toxicity (secondary). Results Good response was reported in 1,041 of 2,260 registered patients; 716 consented to random assignment (MAP, n = 359; MAP plus IFN-α-2b, n = 357), with baseline characteristics balanced by arm. A total of 271 of 357 started IFN-α-2b; 105 stopped early, and 38 continued to receive treatment at data freeze. Refusal and toxicity were the main reasons for never starting IFN-α-2b and for stopping prematurely, respectively. Median IFN-α-2b duration, if started, was 67 weeks. A total of 133 of 268 patients who started IFN-α-2b and provided toxicity information reported grade ≥ 3 toxicity during IFN-α-2b treatment. With median follow-up of 44 months, 3-year EFS for all 716 randomly assigned patients was 76% (95% CI, 72% to 79%); 174 EFS events were reported (MAP, n = 93; MAP plus IFN-α-2b, n = 81). Hazard ratio was 0.83 (95% CI, 0.61 to 1.12; P = .214) from an adjusted Cox model. Conclusion At the preplanned analysis time, MAP plus IFN-α-2b was not statistically different from MAP alone. A considerable proportion of patients never started IFN-α-2b or stopped prematurely. Long-term follow-up for events and survival continues. PMID:26033801

Approximating prediction uncertainty for random forest regression models

Treesearch

John W. Coulston; Christine E. Blinn; Valerie A. Thomas; Randolph H. Wynne

2016-01-01

Machine learning approaches such as random forest have increased for the spatial modeling and mapping of continuous variables. Random forest is a non-parametric ensemble approach, and unlike traditional regression approaches there is no direct quantification of prediction error. Understanding prediction uncertainty is important when using model-based continuous maps as...

Physical realizability of continuous-time quantum stochastic walks

NASA Astrophysics Data System (ADS)

Taketani, Bruno G.; Govia, Luke C. G.; Wilhelm, Frank K.

2018-05-01

Quantum walks are a promising methodology that can be used to both understand and implement quantum information processing tasks. The quantum stochastic walk is a recently developed framework that combines the concept of a quantum walk with that of a classical random walk, through open system evolution of a quantum system. Quantum stochastic walks have been shown to have applications in as far reaching fields as artificial intelligence. However, there are significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution and the physical assumptions underpinning them. We show that general direct implementations would require the complete solution of the underlying unitary dynamics and sophisticated reservoir engineering, thus weakening the benefits of experimental implementation.

Time-invariant PT product and phase locking in PT -symmetric lattice models

NASA Astrophysics Data System (ADS)

Joglekar, Yogesh N.; Onanga, Franck Assogba; Harter, Andrew K.

2018-01-01

Over the past decade, non-Hermitian, PT -symmetric Hamiltonians have been investigated as candidates for both a fundamental, unitary, quantum theory and open systems with a nonunitary time evolution. In this paper, we investigate the implications of the former approach in the context of the latter. Motivated by the invariance of the PT (inner) product under time evolution, we discuss the dynamics of wave-function phases in a wide range of PT -symmetric lattice models. In particular, we numerically show that, starting with a random initial state, a universal, gain-site location dependent locking between wave-function phases at adjacent sites occurs in the PT -symmetry-broken region. Our results pave the way towards understanding the physically observable implications of time invariants in the nonunitary dynamics produced by PT -symmetric Hamiltonians.

Therapeutic touch and postoperative pain: a Rogerian research study.

PubMed

Meehan, T C

1993-01-01

This article details Meehan's research study concerning the conceptualization of therapeutic touch within Rogers' science of unitary human beings and an investigation of the effects of therapeutic touch on pain experience in postoperative patients. Using a single trial, single-blind, three-group design, 108 postoperative patients were randomly assigned to receive one of the following: therapeutic touch, a placebo control intervention which mimicked therapeutic touch, or the standard intervention of a narcotic analgesic. Using a visual analogue scale, pain was measured before and one hour following intervention. The hypothesis, that therapeutic touch would significantly decrease postoperative pain compared to the placebo control intervention, was not supported. Secondary analyses suggest that therapeutic touch may decrease patients' need for analgesic medication. Implications for further research and practice are suggested.

Authenticated Quantum Key Distribution with Collective Detection using Single Photons

NASA Astrophysics Data System (ADS)

Huang, Wei; Xu, Bing-Jie; Duan, Ji-Tong; Liu, Bin; Su, Qi; He, Yuan-Hang; Jia, Heng-Yue

2016-10-01

We present two authenticated quantum key distribution (AQKD) protocols by utilizing the idea of collective (eavesdropping) detection. One is a two-party AQKD protocol, the other is a multiparty AQKD protocol with star network topology. In these protocols, the classical channels need not be assumed to be authenticated and the single photons are used as the quantum information carriers. To achieve mutual identity authentication and establish a random key in each of the proposed protocols, only one participant should be capable of preparing and measuring single photons, and the main quantum ability that the rest of the participants should have is just performing certain unitary operations. Security analysis shows that these protocols are free from various kinds of attacks, especially the impersonation attack and the man-in-the-middle (MITM) attack.

Microwave waveguide manifold and method

DOEpatents

Staehlin, John H.

1987-01-01

A controllably electrically coupled, physically intersecting plural waveguide manifold assembly wherein the intersecting waveguide elements are fabricated in integral unitary relationship from a single piece of metal in order to avoid the inaccuracies and difficult-to-control fabrication steps associated with uniting separate waveguide elements into a unitary structure. An X-band aluminum airborne radar manifold example is disclosed, along with a fabrication sequence for the manifold and the electrical energy communicating apertures joining the manifold elements.

Microwave waveguide manifold and method

DOEpatents

Staehlin, John H.

1987-12-01

A controllably electrically coupled, physically intersecting plural waveguide manifold assembly wherein the intersecting waveguide elements are fabricated in integral unitary relationship from a single piece of metal in order to avoid the inaccuracies and difficult-to-control fabrication steps associated with uniting separate waveguide elements into a unitary structure. An X-band aluminum airborne radar manifold example is disclosed, along with a fabrication sequence for the manifold and the electrical energy communicating apertures joining the manifold elements.

Efimov-driven phase transitions of the unitary Bose gas.

PubMed

Piatecki, Swann; Krauth, Werner

2014-03-20

Initially predicted in nuclear physics, Efimov trimers are bound configurations of three quantum particles that fall apart when any one of them is removed. They open a window into a rich quantum world that has become the focus of intense experimental and theoretical research, as the region of 'unitary' interactions, where Efimov trimers form, is now accessible in cold-atom experiments. Here we use a path-integral Monte Carlo algorithm backed up by theoretical arguments to show that unitary bosons undergo a first-order phase transition from a normal gas to a superfluid Efimov liquid, bound by the same effects as Efimov trimers. A triple point separates these two phases and another superfluid phase, the conventional Bose-Einstein condensate, whose coexistence line with the Efimov liquid ends in a critical point. We discuss the prospects of observing the proposed phase transitions in cold-atom systems.

Quantum Measurement and Initial Conditions

NASA Astrophysics Data System (ADS)

Stoica, Ovidiu Cristinel

2016-03-01

Quantum measurement finds the observed system in a collapsed state, rather than in the state predicted by the Schrödinger equation. Yet there is a relatively spread opinion that the wavefunction collapse can be explained by unitary evolution (for instance in the decoherence approach, if we take into account the environment). In this article it is proven a mathematical result which severely restricts the initial conditions for which measurements have definite outcomes, if pure unitary evolution is assumed. This no-go theorem remains true even if we take the environment into account. The result does not forbid a unitary description of the measurement process, it only shows that such a description is possible only for very restricted initial conditions. The existence of such restrictions of the initial conditions can be understood in the four-dimensional block universe perspective, as a requirement of global self-consistency of the solutions of the Schrödinger equation.

Geometric characterization of separability and entanglement in pure Gaussian states by single-mode unitary operations

NASA Astrophysics Data System (ADS)

Adesso, Gerardo; Giampaolo, Salvatore M.; Illuminati, Fabrizio

2007-10-01

We present a geometric approach to the characterization of separability and entanglement in pure Gaussian states of an arbitrary number of modes. The analysis is performed adapting to continuous variables a formalism based on single subsystem unitary transformations that has been recently introduced to characterize separability and entanglement in pure states of qubits and qutrits [S. M. Giampaolo and F. Illuminati, Phys. Rev. A 76, 042301 (2007)]. In analogy with the finite-dimensional case, we demonstrate that the 1×M bipartite entanglement of a multimode pure Gaussian state can be quantified by the minimum squared Euclidean distance between the state itself and the set of states obtained by transforming it via suitable local symplectic (unitary) operations. This minimum distance, corresponding to a , uniquely determined, extremal local operation, defines an entanglement monotone equivalent to the entropy of entanglement, and amenable to direct experimental measurement with linear optical schemes.

Quench of non-Markovian coherence in the deep sub-Ohmic spin–boson model: A unitary equilibration scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Yao, E-mail: yaoyao@fudan.edu.cn

The deep sub-Ohmic spin–boson model shows a longstanding non-Markovian coherence at low temperature. Motivating to quench this robust coherence, the thermal effect is unitarily incorporated into the time evolution of the model, which is calculated by the adaptive time-dependent density matrix renormalization group algorithm combined with the orthogonal polynomials theory. Via introducing a unitary heating operator to the bosonic bath, the bath is heated up so that a majority portion of the bosonic excited states is occupied. It is found in this situation the coherence of the spin is quickly quenched even in the coherent regime, in which the non-Markovianmore » feature dominates. With this finding we come up with a novel way to implement the unitary equilibration, the essential term of the eigenstate-thermalization hypothesis, through a short-time evolution of the model.« less

Black hole thermodynamics based on unitary evolutions

NASA Astrophysics Data System (ADS)

Feng, Yu-Lei; Chen, Yi-Xin

2015-10-01

In this paper, we try to construct black hole thermodynamics based on the fact that the formation and evaporation of a black hole can be described by quantum unitary evolutions. First, we show that the Bekenstein-Hawking entropy SBH may not be a Boltzmann or thermal entropy. To confirm this statement, we show that the original black hole's ‘first law’ may not simply be treated as the first law of thermodynamics formally, due to some missing metric perturbations caused by matter. Then, by including those (quantum) metric perturbations, we show that the black hole formation and evaporation can be described effectively in a unitary manner, through a quantum channel between the exterior and interior of the event horizon. In this way, the paradoxes of information loss and firewall can be resolved effectively. Finally, we show that black hole thermodynamics can be constructed in an ordinary way, by constructing statistical mechanics.

Extended Thomas-Fermi density functional for the unitary Fermi gas

NASA Astrophysics Data System (ADS)

Salasnich, Luca; Toigo, Flavio

2008-11-01

We determine the energy density ξ(3/5)nɛF and the gradient correction λℏ2(∇n)2/(8mn) of the extended Thomas-Fermi (ETF) density functional, where n is the number density and ɛF is the Fermi energy, for a trapped two-component Fermi gas with infinite scattering length (unitary Fermi gas) on the basis of recent diffusion Monte Carlo (DMC) calculations [Phys. Rev. Lett. 99, 233201 (2007)]. In particular we find that ξ=0.455 and λ=0.13 give the best fit of the DMC data with an even number N of particles. We also study the odd-even splitting γN1/9ℏω of the ground-state energy for the unitary gas in a harmonic trap of frequency ω determining the constant γ . Finally we investigate the effect of the gradient term in the time-dependent ETF model by introducing generalized Galilei-invariant hydrodynamics equations.

Validating simple dynamical simulations of the unitary Fermi gas

NASA Astrophysics Data System (ADS)

Forbes, Michael McNeil; Sharma, Rishi

2014-10-01

We present a comparison between simulated dynamics of the unitary fermion gas using the superfluid local density approximation (SLDA) and a simplified bosonic model, the extended Thomas-Fermi (ETF) with a unitary equation of state. Small-amplitude fluctuations have similar dynamics in both theories for frequencies far below the pair-breaking threshold and wave vectors much smaller than the Fermi momentum. The low-frequency linear responses in both match well for surprisingly large wave vectors, even up to the Fermi momentum. For nonlinear dynamics such as vortex generation, the ETF provides a semiquantitative description of SLDA dynamics as long as the fluctuations do not have significant power near the pair-breaking threshold; otherwise the dynamics of the ETF cannot be trusted. Nonlinearities in the ETF tend to generate high-frequency fluctuations, and with no normal component to remove this energy from the superfluid, features such as vortex lattices cannot relax and crystallize as they do in the SLDA.

Study of optical techniques for the Ames unitary wind tunnels. Part 3: Angle of attack

NASA Technical Reports Server (NTRS)

Lee, George

1992-01-01

A review of optical sensors that are capable of accurate angle of attack measurements in wind tunnels was conducted. These include sensors being used or being developed at NASA Ames and Langley Research Centers, Boeing Airplane Company, McDonald Aircraft Company, Arnold Engineering Development Center, National Aerospace Laboratory of the Netherlands, National Research Council of Canada, and the Royal Aircraft Establishment of England. Some commercial sensors that may be applicable to accurate angle measurements were also reviewed. It was found that the optical sensor systems were based on interferometers, polarized light detector, linear or area photodiode cameras, position sensing photodetectors, and laser scanners. Several of the optical sensors can meet the requirements of the Ames Unitary Plan Wind Tunnel. Two of these, the Boeing interferometer and the Complere lateral effect photodiode sensors are being developed for the Ames Unitary Plan Wind Tunnel.

Operational flow visualization techniques in the Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Corlett, W. A.

1982-01-01

The unitary plan wind tunnel (UPWT) uses in daily operation are shown. New ideas for improving the quality of established flow visualization methods are developed and programs on promising new flow visualization techniques are pursued. The unitary plan wind tunnel is a supersonic facility, referred to as a production facility, although the majority of tests are inhouse basic research investigations. The facility has two 4 ft. by 4 ft. test sections which span a Mach range from 1.5 to 4.6. The cost of operation is about $10 per minute. Problems are the time required for a flow visualization test setup and investigation costs and the ability to obtain consistently repeatable results. Examples of sublimation, vapor screen, oil flow, minitufts, schlieren, and shadowgraphs taken in UPWT are presented. All tests in UPWT employ one or more of the flow visualization techniques.

Quadratic time dependent Hamiltonians and separation of variables

NASA Astrophysics Data System (ADS)

Anzaldo-Meneses, A.

2017-06-01

Time dependent quantum problems defined by quadratic Hamiltonians are solved using canonical transformations. The Green's function is obtained and a comparison with the classical Hamilton-Jacobi method leads to important geometrical insights like exterior differential systems, Monge cones and time dependent Gaussian metrics. The Wei-Norman approach is applied using unitary transformations defined in terms of generators of the associated Lie groups, here the semi-direct product of the Heisenberg group and the symplectic group. A new explicit relation for the unitary transformations is given in terms of a finite product of elementary transformations. The sequential application of adequate sets of unitary transformations leads naturally to a new separation of variables method for time dependent Hamiltonians, which is shown to be related to the Inönü-Wigner contraction of Lie groups. The new method allows also a better understanding of interacting particles or coupled modes and opens an alternative way to analyze topological phases in driven systems.

Violation of unitarity by Hawking radiation does not violate energy-momentum conservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikolić, Hrvoje

2015-04-02

An argument by Banks, Susskind and Peskin (BSP), according to which violation of unitarity would violate either locality or energy-momentum conservation, is widely believed to be a strong argument against non-unitarity of Hawking radiation. We find that the whole BSP argument rests on the crucial assumption that the Hamiltonian is not highly degenerate, and point out that this assumption is not satisfied for systems with many degrees of freedom. Using Lindblad equation, we show that high degeneracy of the Hamiltonian allows local non-unitary evolution without violating energy-momentum conservation. Moreover, since energy-momentum is the source of gravity, we argue that energy-momentummore » is necessarily conserved for a large class of non-unitary systems with gravity. Finally, we explicitly calculate the Lindblad operators for non-unitary Hawking radiation and show that they conserve energy-momentum.« less

Effect of randomness in logistic maps

NASA Astrophysics Data System (ADS)

Khaleque, Abdul; Sen, Parongama

2015-01-01

We study a random logistic map xt+1 = atxt[1 - xt] where at are bounded (q1 ≤ at ≤ q2), random variables independently drawn from a distribution. xt does not show any regular behavior in time. We find that xt shows fully ergodic behavior when the maximum allowed value of at is 4. However , averaged over different realizations reaches a fixed point. For 1 ≤ at ≤ 4, the system shows nonchaotic behavior and the Lyapunov exponent is strongly dependent on the asymmetry of the distribution from which at is drawn. Chaotic behavior is seen to occur beyond a threshold value of q1(q2) when q2(q1) is varied. The most striking result is that the random map is chaotic even when q2 is less than the threshold value 3.5699⋯ at which chaos occurs in the nonrandom map. We also employ a different method in which a different set of random variables are used for the evolution of two initially identical x values, here the chaotic regime exists for all q1 ≠ q2 values.

Intermediate quantum maps for quantum computation

NASA Astrophysics Data System (ADS)

Giraud, O.; Georgeot, B.

2005-10-01

We study quantum maps displaying spectral statistics intermediate between Poisson and Wigner-Dyson. It is shown that they can be simulated on a quantum computer with a small number of gates, and efficiently yield information about fidelity decay or spectral statistics. We study their matrix elements and entanglement production and show that they converge with time to distributions which differ from random matrix predictions. A randomized version of these maps can be implemented even more economically and yields pseudorandom operators with original properties, enabling, for example, one to produce fractal random vectors. These algorithms are within reach of present-day quantum computers.

Stimulus novelty, task relevance and the visual evoked potential in man

NASA Technical Reports Server (NTRS)

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

The effect of task relevance on P3 (waveform of human evoked potential) waves and the methodologies used to deal with them are outlined. Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli. Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable, and novels, which were completely unrecognizable. It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves while the irrelevant novels evoked large, frontally distributed P3 waves. These large, frontal P3 waves to novels were also found to be preceded by large N2 waves. These findings indicate that the P3 wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates.

Quantum Ultra-Walks: Walks on a Line with Spatial Disorder

NASA Astrophysics Data System (ADS)

Boettcher, Stefan; Falkner, Stefan

We discuss the model of a heterogeneous discrete-time walk on a line with spatial disorder in the form of a set of ultrametric barriers. Simulations show that such an quantum ultra-walk spreads with a walk exponent dw that ranges from ballistic (dw = 1) to complete confinement (dw = ∞) for increasing separation 1 <= 1 / ɛ < ∞ in barrier heights. We develop a formalism by which the classical random walk as well as the quantum walk can be treated in parallel using a coined walk with internal degrees of freedom. For the random walk, this amounts to a 2nd -order Markov process with a stochastic coin, better know as an (anti-)persistent walk. The exact analysis, based on the real-space renormalization group (RG), reproduces the results of the well-known model of ``ultradiffusion,'' dw = 1 -log2 ɛ for 0 < ɛ <= 1 / 2 . However, while the evaluation of the RG fixed-points proceeds virtually identical, for the corresponding quantum walk with a unitary coin it fails to reproduce the numerical results. A new way to analyze the RG is indicated. Supported by NSF-DMR 1207431.

The randomized benchmarking number is not what you think it is

NASA Astrophysics Data System (ADS)

Proctor, Timothy; Rudinger, Kenneth; Blume-Kohout, Robin; Sarovar, Mohan; Young, Kevin

Randomized benchmarking (RB) is a widely used technique for characterizing a gate set, whereby random sequences of gates are used to probe the average behavior of the gate set. The gates are chosen to ideally compose to the identity, and the rate of decay in the survival probability of an initial state with increasing length sequences is extracted from a set of experiments - this is the `RB number'. For reasonably well-behaved noise and particular gate sets, it has been claimed that the RB number is a reliable estimate of the average gate fidelity (AGF) of each noisy gate to the ideal target unitary, averaged over all gates in the set. Contrary to this widely held view, we show that this is not the case. We show that there are physically relevant situations, in which RB was thought to be provably reliable, where the RB number is many orders of magnitude away from the AGF. These results have important implications for interpreting the RB protocol, and immediate consequences for many advanced RB techniques. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Relation between random walks and quantum walks

NASA Astrophysics Data System (ADS)

Boettcher, Stefan; Falkner, Stefan; Portugal, Renato

2015-05-01

Based on studies of four specific networks, we conjecture a general relation between the walk dimensions dw of discrete-time random walks and quantum walks with the (self-inverse) Grover coin. In each case, we find that dw of the quantum walk takes on exactly half the value found for the classical random walk on the same geometry. Since walks on homogeneous lattices satisfy this relation trivially, our results for heterogeneous networks suggest that such a relation holds irrespective of whether translational invariance is maintained or not. To develop our results, we extend the renormalization-group analysis (RG) of the stochastic master equation to one with a unitary propagator. As in the classical case, the solution ρ (x ,t ) in space and time of this quantum-walk equation exhibits a scaling collapse for a variable xdw/t in the weak limit, which defines dw and illuminates fundamental aspects of the walk dynamics, e.g., its mean-square displacement. We confirm the collapse for ρ (x ,t ) in each case with extensive numerical simulation. The exact values for dw themselves demonstrate that RG is a powerful complementary approach to study the asymptotics of quantum walks that weak-limit theorems have not been able to access, such as for systems lacking translational symmetries beyond simple trees.

Physics Without Causality — Theory and Evidence

NASA Astrophysics Data System (ADS)

Shoup, Richard

2006-10-01

The principle of cause and effect is deeply rooted in human experience, so much so that it is routinely and tacitly assumed throughout science, even by scientists working in areas where time symmetry is theoretically ingrained, as it is in both classical and quantum physics. Experiments are said to cause their results, not the other way around. In this informal paper, we argue that this assumption should be replaced with a more general notion of mutual influence — bi-directional relations or constraints on joint values of two or more variables. From an analysis based on quantum entropy, it is proposed that quantum measurement is a unitary three-interaction, with no collapse, no fundamental randomness, and no barrier to backward influence. Experimental results suggesting retrocausality are seen frequently in well-controlled laboratory experiments in parapsychology and elsewhere, especially where a random element is included. Certain common characteristics of these experiments give the appearance of contradicting well-established physical laws, thus providing an opportunity for deeper understanding and important clues that must be addressed by any explanatory theory. We discuss how retrocausal effects and other anomalous phenomena can be explained without major injury to existing physical theory. A modified quantum formalism can give new insights into the nature of quantum measurement, randomness, entanglement, causality, and time.

Generalized Quantum Theory and Mathematical Foundations of Quantum Field Theory

NASA Astrophysics Data System (ADS)

Maroun, Michael Anthony

This dissertation is divided into two main topics. The first is the generalization of quantum dynamics when the Schrodinger partial differential equation is not defined even in the weak mathematical sense because the potential function itself is a distribution in the spatial variable, the same variable that is used to define the kinetic energy operator, i.e. the Laplace operator. The procedure is an extension and broadening of the distributional calculus and offers spectral results as an alternative to the only other two known methods to date, namely a) the functional calculi; and b) non-standard analysis. Furthermore, the generalizations of quantum dynamics presented within give a resolution to the time asymmetry paradox created by multi-particle quantum mechanics due to the time evolution still being unitary. A consequence is the randomization of phases needed for the fundamental justification Pauli master equation. The second topic is foundations of the quantum theory of fields. The title is phrased as ``foundations'' to emphasize that there is no claim of uniqueness but rather a proposal is put forth, which is markedly different than that of constructive or axiomatic field theory. In particular, the space of fields is defined as a space of generalized functions with involutive symmetry maps (the CPT invariance) that affect the topology of the field space. The space of quantum fields is then endowed the Frechet property and interactions change the topology in such a way as to cause some field spaces to be incompatible with others. This is seen in the consequences of the Haag theorem. Various examples and discussions are given that elucidate a new view of the quantum theory of fields and its (lack of) mathematical structure.

Semiclassical electron transport at the edge of a two-dimensional topological insulator: Interplay of protected and unprotected modes

NASA Astrophysics Data System (ADS)

Khalaf, E.; Skvortsov, M. A.; Ostrovsky, P. M.

2016-03-01

We study electron transport at the edge of a generic disordered two-dimensional topological insulator, where some channels are topologically protected from backscattering. Assuming the total number of channels is large, we consider the edge as a quasi-one-dimensional quantum wire and describe it in terms of a nonlinear sigma model with a topological term. Neglecting localization effects, we calculate the average distribution function of transmission probabilities as a function of the sample length. We mainly focus on the two experimentally relevant cases: a junction between two quantum Hall (QH) states with different filling factors (unitary class) and a relatively thick quantum well exhibiting quantum spin Hall (QSH) effect (symplectic class). In a QH sample, the presence of topologically protected modes leads to a strong suppression of diffusion in the other channels already at scales much shorter than the localization length. On the semiclassical level, this is accompanied by the formation of a gap in the spectrum of transmission probabilities close to unit transmission, thereby suppressing shot noise and conductance fluctuations. In the case of a QSH system, there is at most one topologically protected edge channel leading to weaker transport effects. In order to describe `topological' suppression of nearly perfect transparencies, we develop an exact mapping of the semiclassical limit of the one-dimensional sigma model onto a zero-dimensional sigma model of a different symmetry class, allowing us to identify the distribution of transmission probabilities with the average spectral density of a certain random-matrix ensemble. We extend our results to other symmetry classes with topologically protected edges in two dimensions.

Margaret Newman's Theory of Health as Expanding Consciousness and a Nursing Intervention from a Unitary Perspective

PubMed Central

Endo, Emiko

2017-01-01

This mini-review aims to introduce Margaret Newman's theory of health as expanding consciousness and caring partnership as a nursing intervention. Emanating from a unitary and transformative perspective of nursing, caring partnership enables nurses to identify with cancer patients as well as to help the patients find meaning in their situation and their lives. In genuine patient–nurse interactions, both patients and nurses experience higher levels of consciousness. PMID:28217730

Biophysically Based Mathematical Modeling of Interstitial Cells of Cajal Slow Wave Activity Generated from a Discrete Unitary Potential Basis

PubMed Central

Faville, R.A.; Pullan, A.J.; Sanders, K.M.; Koh, S.D.; Lloyd, C.M.; Smith, N.P.

2009-01-01

Abstract Spontaneously rhythmic pacemaker activity produced by interstitial cells of Cajal (ICC) is the result of the entrainment of unitary potential depolarizations generated at intracellular sites termed pacemaker units. In this study, we present a mathematical modeling framework that quantitatively represents the transmembrane ion flows and intracellular Ca2+ dynamics from a single ICC operating over the physiological membrane potential range. The mathematical model presented here extends our recently developed biophysically based pacemaker unit modeling framework by including mechanisms necessary for coordinating unitary potential events, such as a T-Type Ca2+ current, Vm-dependent K+ currents, and global Ca2+ diffusion. Model simulations produce spontaneously rhythmic slow wave depolarizations with an amplitude of 65 mV at a frequency of 17.4 cpm. Our model predicts that activity at the spatial scale of the pacemaker unit is fundamental for ICC slow wave generation, and Ca2+ influx from activation of the T-Type Ca2+ current is required for unitary potential entrainment. These results suggest that intracellular Ca2+ levels, particularly in the region local to the mitochondria and endoplasmic reticulum, significantly influence pacing frequency and synchronization of pacemaker unit discharge. Moreover, numerical investigations show that our ICC model is capable of qualitatively replicating a wide range of experimental observations. PMID:19527643

Engineering multiphoton states for linear optics computation

NASA Astrophysics Data System (ADS)

Aniello, P.; Lupo, C.; Napolitano, M.; Paris, M. G. A.

2007-03-01

Transformations achievable by linear optical components allow to generate the whole unitary group only when restricted to the one-photon subspace of a multimode Fock space. In this paper, we address the more general problem of encoding quantum information by multiphoton states, and elaborating it via ancillary extensions, linear optical passive devices and photodetection. Our scheme stems in a natural way from the mathematical structures underlying the physics of linear optical passive devices. In particular, we analyze an economical procedure for mapping a fiducial 2-photon 2-mode state into an arbitrary 2-photon 2-mode state using ancillary resources and linear optical passive N-ports assisted by post-selection. We found that adding a single ancilla mode is enough to generate any desired target state. The effect of imperfect photodetection in post-selection is considered and a simple trade-off between success probability and fidelity is derived.

Surveying the quantum group symmetries of integrable open spin chains

NASA Astrophysics Data System (ADS)

Nepomechie, Rafael I.; Retore, Ana L.

2018-05-01

Using anisotropic R-matrices associated with affine Lie algebras g ˆ (specifically, A2n(2), A2n-1 (2) , Bn(1), Cn(1), Dn(1)) and suitable corresponding K-matrices, we construct families of integrable open quantum spin chains of finite length, whose transfer matrices are invariant under the quantum group corresponding to removing one node from the Dynkin diagram of g ˆ . We show that these transfer matrices also have a duality symmetry (for the cases Cn(1) and Dn(1)) and additional Z2 symmetries that map complex representations to their conjugates (for the cases A2n-1 (2) , Bn(1) and Dn(1)). A key simplification is achieved by working in a certain "unitary" gauge, in which only the unbroken symmetry generators appear. The proofs of these symmetries rely on some new properties of the R-matrices. We use these symmetries to explain the degeneracies of the transfer matrices.

Rapid resetting of rabbit aortic baroreceptors and reflex heart rate responses by directional changes in blood pressure.

PubMed

Burke, S L; Dorward, P K; Korner, P I

1986-09-01

In both anaesthetized and conscious rabbits, perivascular balloon inflations slowly raised or lowered mean arterial pressure (M.A.P.), at 1-2 mmHg/s, from resting to various plateau pressures. Deflations then returned the M.A.P. to resting. 'Steady-state' curves relating M.A.P. to unitary aortic baroreceptor firing, integrated aortic nerve activity and heart rate were derived during the primary and return pressure changes and they formed typical hysteresis loops. In single units, return M.A.P.-frequency curves were shifted in the same direction as the primary pressure changes by an average 0.37 mmHg per mmHg change in M.A.P. Shifts were linearly related to the changes in M.A.P. between resting and plateau levels for all pressure rises and for falls less than 30 mmHg. They were established within 30 s and were quantitatively similar to the rapid resetting of baroreceptor function curves found 15 min-2 h after a change in resting M.A.P. (Dorward, Andresen, Burke, Oliver & Korner, 1982). Unit threshold pressures were shifted within 20 s to the same extent as the over-all curve shift to which they contributed. In the whole aortic nerve, return M.A.P.-integrated activity curves were shifted to same degree as unit function curves in both anaesthetized and conscious rabbits. Simultaneous shifts of return reflex M.A.P.-heart rate curves were also seen in conscious rabbits within 30 s. During M.A.P. falls, receptor and reflex hysteresis was similar, but during M.A.P. rises, reflex shifts were double baroreceptor shifts, suggesting the involvement of other pressure-sensitive receptors. We conclude that hysteresis shifts in baroreceptor function curves, which follow the reversal of slow ramp changes in blood pressure are a form of rapid resetting. They are accompanied by rapid resetting of reflex heart rate responses. We regard this as an important mechanism in blood pressure control which produces relatively high-gain reflex responses, during slow directional pressure changes, over a wider range of absolute pressure levels than would otherwise be possible.

Averaged kick maps: less noise, more signal…and probably less bias

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pražnikar, Jure; Afonine, Pavel V.; Gunčar, Gregor

2009-09-01

Averaged kick maps are the sum of a series of individual kick maps, where each map is calculated from atomic coordinates modified by random shifts. These maps offer the possibility of an improved and less model-biased map interpretation. Use of reliable density maps is crucial for rapid and successful crystal structure determination. Here, the averaged kick (AK) map approach is investigated, its application is generalized and it is compared with other map-calculation methods. AK maps are the sum of a series of kick maps, where each kick map is calculated from atomic coordinates modified by random shifts. As such, theymore » are a numerical analogue of maximum-likelihood maps. AK maps can be unweighted or maximum-likelihood (σ{sub A}) weighted. Analysis shows that they are comparable and correspond better to the final model than σ{sub A} and simulated-annealing maps. The AK maps were challenged by a difficult structure-validation case, in which they were able to clarify the problematic region in the density without the need for model rebuilding. The conclusion is that AK maps can be useful throughout the entire progress of crystal structure determination, offering the possibility of improved map interpretation.« less

Determining the best forecasting method to estimate unitary charges price indexes of PFI data in central region Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Ahmad Kamaruddin, Saadi Bin; Md Ghani, Nor Azura; Mohamed Ramli, Norazan

2013-04-01

The concept of Private Financial Initiative (PFI) has been implemented by many developed countries as an innovative way for the governments to improve future public service delivery and infrastructure procurement. However, the idea is just about to germinate in Malaysia and its success is still vague. The major phase that needs to be given main attention in this agenda is value for money whereby optimum efficiency and effectiveness of each expense is attained. Therefore, at the early stage of this study, estimating unitary charges or materials price indexes in each region in Malaysia was the key objective. This particular study aims to discover the best forecasting method to estimate unitary charges price indexes in construction industry by different regions in the central region of Peninsular Malaysia (Selangor, Federal Territory of Kuala Lumpur, Negeri Sembilan, and Melaka). The unitary charges indexes data used were from year 2002 to 2011 monthly data of different states in the central region Peninsular Malaysia, comprising price indexes of aggregate, sand, steel reinforcement, ready mix concrete, bricks and partition, roof material, floor and wall finishes, ceiling, plumbing materials, sanitary fittings, paint, glass, steel and metal sections, timber and plywood. At the end of the study, it was found that Backpropagation Neural Network with linear transfer function produced the most accurate and reliable results for estimating unitary charges price indexes in every states in central region Peninsular Malaysia based on the Root Mean Squared Errors, where the values for both estimation and evaluation sets were approximately zero and highly significant at p < 0.01. Therefore, artificial neural network is sufficient to forecast construction materials price indexes in Malaysia. The estimated price indexes of construction materials will contribute significantly to the value for money of PFI as well as towards Malaysian economical growth.

Knowledge Representation for Decision Making Agents

DTIC Science & Technology

2013-07-15

knowledge map. This knowledge map is a dictionary data structure called tmap in the code. It represents a network of locations with a number [0,1...fillRandom(): Informed initial tmap distribution (randomly generated per node) with belief one. • initialBelief = 3 uses fillCenter(): normal...triggered on AllMyFMsHaveBeenInitialized. 2. Executes main.py • Initializes knowledge map labeled tmap . • Calls initialize search() – resets distanceTot and

Random pure states: Quantifying bipartite entanglement beyond the linear statistics.

PubMed

Vivo, Pierpaolo; Pato, Mauricio P; Oshanin, Gleb

2016-05-01

We analyze the properties of entangled random pure states of a quantum system partitioned into two smaller subsystems of dimensions N and M. Framing the problem in terms of random matrices with a fixed-trace constraint, we establish, for arbitrary N≤M, a general relation between the n-point densities and the cross moments of the eigenvalues of the reduced density matrix, i.e., the so-called Schmidt eigenvalues, and the analogous functionals of the eigenvalues of the Wishart-Laguerre ensemble of the random matrix theory. This allows us to derive explicit expressions for two-level densities, and also an exact expression for the variance of von Neumann entropy at finite N,M. Then, we focus on the moments E{K^{a}} of the Schmidt number K, the reciprocal of the purity. This is a random variable supported on [1,N], which quantifies the number of degrees of freedom effectively contributing to the entanglement. We derive a wealth of analytical results for E{K^{a}} for N=2 and 3 and arbitrary M, and also for square N=M systems by spotting for the latter a connection with the probability P(x_{min}^{GUE}≥sqrt[2N]ξ) that the smallest eigenvalue x_{min}^{GUE} of an N×N matrix belonging to the Gaussian unitary ensemble is larger than sqrt[2N]ξ. As a by-product, we present an exact asymptotic expansion for P(x_{min}^{GUE}≥sqrt[2N]ξ) for finite N as ξ→∞. Our results are corroborated by numerical simulations whenever possible, with excellent agreement.

Energy-absorption spectroscopy of unitary Fermi gases in a uniform potential

NASA Astrophysics Data System (ADS)

Zhang, Pengfei; Yu, Zhenhua

2018-04-01

We propose to use the energy absorption spectroscopy to measure the kinetic coefficients of unitary Fermi gases in a uniform potential. We show that, in our scheme, the energy absorption spectrum is proportional to the dynamic structure factor of the system. The profile of the spectrum depends on the shear viscosity η , the thermal conductivity κ , and the superfluid bulk viscosity ξ3. We show that extraction of these coefficients from the spectrum is achievable in present experiments.

Power, trust, and Science of Unitary Human Beings influence political leadership: a celebration of Barrett's power theory.

PubMed

Wright, Barbara W

2010-01-01

The importance of nurses' participation in health policy leadership is discussed within the context of Rogers' science of unitary human beings, Barrett's power theory, and one nurse-politician's experience. Nurses have a major role to play in resolving public policy issues that influence the health of people. A brief review of the history of nurses in the political arena is presented. Research related to power and trust is reviewed. Suggested strategies for success in political situations are offered.

ARC-2006-ACD06-0213-010

NASA Image and Video Library

2006-10-03

Ames and Moffett Field (MFA) historical sites and memorials Unitary Plan Wind Tunned plaza; display and historical site plaques with the NASA logo on the Wind Tunnel valve as a backdrop. Plaque depicts that Ames Unitary Plan Wind Tunnel has been designated a National Historic Landmark by the National Park Service, United States Department of the Interior 1985 The plaque reads; This site possesses national significance in commemorating the history of the United States of America. That ceremony took place on September 12, 1990

Study of optical techniques for the Ames unitary wind tunnel: Digital image processing, part 6

NASA Technical Reports Server (NTRS)

Lee, George

1993-01-01

A survey of digital image processing techniques and processing systems for aerodynamic images has been conducted. These images covered many types of flows and were generated by many types of flow diagnostics. These include laser vapor screens, infrared cameras, laser holographic interferometry, Schlieren, and luminescent paints. Some general digital image processing systems, imaging networks, optical sensors, and image computing chips were briefly reviewed. Possible digital imaging network systems for the Ames Unitary Wind Tunnel were explored.

Local unitary invariants for N-qubit pure states

NASA Astrophysics Data System (ADS)

Sharma, S. Shelly; Sharma, N. K.

2010-11-01

The concept of negativity font, a basic unit of multipartite entanglement, is introduced. Transformation properties of determinants of negativity fonts under local unitary (LU) transformations are exploited to obtain relevant N-qubit polynomial invariants and construct entanglement monotones from first principles. It is shown that entanglement monotones that detect the entanglement of specific parts of the composite system may be constructed to distinguish between states with distinct types of entanglement. The structural difference between entanglement monotones for an odd and even number of qubits is brought out.

Study of optical techniques for the Ames unitary wind tunnel. Part 5: Infrared imagery

NASA Technical Reports Server (NTRS)

Lee, George

1992-01-01

A survey of infrared thermography for aerodynamics was made. Particular attention was paid to boundary layer transition detection. IR thermography flow visualization of 2-D and 3-D separation was surveyed. Heat transfer measurements and surface temperature measurements were also covered. Comparisons of several commercial IR cameras were made. The use of a recently purchased IR camera in the Ames Unitary Plan Wind Tunnels was studied. Optical access for these facilities and the methods to scan typical models was investigated.

Preparation of freezing quantum state for quantum coherence

NASA Astrophysics Data System (ADS)

Yang, Lian-Wu; Man, Zhong-Xiao; Zhang, Ying-Jie; Han, Feng; Du, Shao-jiang; Xia, Yun-Jie

2018-06-01

We provide a method to prepare the freezing quantum state for quantum coherence via unitary operations. The initial product state consists of the control qubit and target qubit; when it satisfies certain conditions, the initial product state converts into the particular Bell diagonal state under the unitary operations, which have the property of freezing of quantum coherence under quantum channels. We calculate the frozen quantum coherence and corresponding quantum correlations, and find that the quantities are determined by the control qubit only when the freezing phenomena occur.

The conformal characters

NASA Astrophysics Data System (ADS)

Bourget, Antoine; Troost, Jan

2018-04-01

We revisit the study of the multiplets of the conformal algebra in any dimension. The theory of highest weight representations is reviewed in the context of the Bernstein-Gelfand-Gelfand category of modules. The Kazhdan-Lusztig polynomials code the relation between the Verma modules and the irreducible modules in the category and are the key to the characters of the conformal multiplets (whether finite dimensional, infinite dimensional, unitary or non-unitary). We discuss the representation theory and review in full generality which representations are unitarizable. The mathematical theory that allows for both the general treatment of characters and the full analysis of unitarity is made accessible. A good understanding of the mathematics of conformal multiplets renders the treatment of all highest weight representations in any dimension uniform, and provides an overarching comprehension of case-by-case results. Unitary highest weight representations and their characters are classified and computed in terms of data associated to cosets of the Weyl group of the conformal algebra. An executive summary is provided, as well as look-up tables up to and including rank four.

THE EIGHTFOLD WAY: A THEORY OF STRONG INTERACTION SYMMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gell-Mann, M.

1961-03-15

A new model of the higher symmetry of elementary particles is introduced ln which the eight known baryons are treated as a supermultiplet, degenerate in the limit of unitary symmetry but split into isotopic spin multiplets by a symmetry-breaking term. The symmetry violation is sscribed phenomenologically to the mass differences. The baryons correspond to an eight-dimensional irreducible representation of the unitary group. The pion and K meson fit into a similar set of eight particles along with a predicted pseudoscalar meson X/sup o/ having I = 0. A ninth vector meson coupled to the baryon current can be accomodated natarallymore » in the scheme. It is predicted that the eight baryons should all have the same spin and parity and that pseudoscalar and vector mesons should form octets with possible additional singlets. The mathematics of the unitary group is described by considering three fictitious leptons, nu , e/sup -/ , and mu /sup -/, which may throw light on the structure of weak interactions. (D. L.C.)« less

ARES I Aerodynamic Testing at the NASA Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Erickson, Gary E.; Wilcox, Floyd J.

2011-01-01

Small-scale force and moment and pressure models based on the outer mold lines of the Ares I design analysis cycle crew launch vehicle were tested in the NASA Langley Research Center Unitary Plan Wind Tunnel from May 2006 to September 2009. The test objectives were to establish supersonic ascent aerodynamic databases and to obtain force and moment, surface pressure, and longitudinal line-load distributions for comparison to computational predictions. Test data were obtained at low through high supersonic Mach numbers for ranges of the Reynolds number, angle of attack, and roll angle. This paper focuses on (1) the sensitivity of the supersonic aerodynamic characteristics to selected protuberances, outer mold line changes, and wind tunnel boundary layer transition techniques, (2) comparisons of experimental data to computational predictions, and (3) data reproducibility. The experimental data obtained in the Unitary Plan Wind Tunnel captured the effects of evolutionary changes to the Ares I crew launch vehicle, exhibited good agreement with predictions, and displayed satisfactory within-test and tunnel-to-tunnel data reproducibility.

On the construction of unitary quantum group differential calculus

NASA Astrophysics Data System (ADS)

Pyatov, Pavel

2016-10-01

We develop a construction of the unitary type anti-involution for the quantized differential calculus over {{GL}}q(n) in the case | q| =1. To this end, we consider a joint associative algebra of quantized functions, differential forms and Lie derivatives over {{GL}}q(n)/{{SL}}q(n), which is bicovariant with respect to {{GL}}q(n)/{{SL}}q(n) coactions. We define a specific non-central spectral extension of this algebra by the spectral variables of three matrices of the algebra generators. In the spectrally expended algebra, we construct a three-parametric family of its inner automorphisms. These automorphisms are used for the construction of the unitary anti-involution for the (spectrally extended) calculus over {{GL}}q(n). This work has been funded by the Russian Academic Excellence Project ‘5-100’. The results of section 5 (propositions 5.2, 5.3 and theorem 5.5) have been obtained under support of the RSF grant No.16-11-10160.

Floquet topological phases with symmetry in all dimensions

NASA Astrophysics Data System (ADS)

Roy, Rahul; Harper, Fenner

2017-05-01

Dynamical systems may host a number of remarkable symmetry-protected phases that are qualitatively different from their static analogs. In this work, we consider the phase space of symmetry-respecting unitary evolutions in detail and identify several distinct classes of evolution that host dynamical order. Using ideas from group cohomology, we construct a set of interacting Floquet drives that generate dynamical symmetry-protected topological order for each nontrivial cohomology class in every dimension, illustrating our construction with explicit two-dimensional examples. We also identify a set of symmetry-protected Floquet drives that lie outside of the group cohomology construction, and a further class of symmetry-respecting topological drives which host chiral edge modes. We use these special drives to define a notion of phase (stable to a class of local perturbations in the bulk) and the concepts of relative and absolute topological order, which can be applied to many different classes of unitary evolutions. These include fully many-body localized unitary evolutions and time crystals.

Geometric characterization of separability and entanglement in pure Gaussian states by single-mode unitary operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adesso, Gerardo; CNR-INFM Coherentia, Naples; CNISM, Unita di Salerno, Salerno

2007-10-15

We present a geometric approach to the characterization of separability and entanglement in pure Gaussian states of an arbitrary number of modes. The analysis is performed adapting to continuous variables a formalism based on single subsystem unitary transformations that has been recently introduced to characterize separability and entanglement in pure states of qubits and qutrits [S. M. Giampaolo and F. Illuminati, Phys. Rev. A 76, 042301 (2007)]. In analogy with the finite-dimensional case, we demonstrate that the 1xM bipartite entanglement of a multimode pure Gaussian state can be quantified by the minimum squared Euclidean distance between the state itself andmore » the set of states obtained by transforming it via suitable local symplectic (unitary) operations. This minimum distance, corresponding to a, uniquely determined, extremal local operation, defines an entanglement monotone equivalent to the entropy of entanglement, and amenable to direct experimental measurement with linear optical schemes.« less

The Ξ* and Ωη Interaction Within a Chiral Unitary Approach

NASA Astrophysics Data System (ADS)

Xu, Si-Qi; Xie, Ju-Jun; Chen, Xu-Rong; Jia, Duo-Jie

2016-01-01

In this work we study the interaction of the coupled channels Ωη and {\\Xi}\\ast\\bar{K} within the chiral unitary approach. The systems under consideration have total isospins 0, strangeness S = -3, and spin 3/2. We study the s wave interaction which implies that the possible resonances generated in the system can have spin-parity JP = 3/2-. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances. We find there is a dynamically generated 3/2- Ω state with mass around 1800 MeV, which is in agreement with the predictions of the five-quark model. Supported by the National Basic Research Program (973 Program Grant No. 2014CB845406), and the National Natural Science Foundation of China under Grant Nos. 11475227, 11265014, and the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China No. Y5KF151CJ1

Radio-Frequency-Controlled Cold Collisions and Universal Properties of Unitary Bose Gases

NASA Astrophysics Data System (ADS)

Ding, Yijue

This thesis investigates two topics: ultracold atomic collisions in a radio-frequency field and universal properties of a degenerate unitary Bose gas. One interesting point of the unitary Bose gas is that the system has only one length scale, that is, the average interparticle distance. This single parameter determines all properties of the gas, which is called the universality of the system. We first introduce a renormalized contact interaction to extend the validity of the zero-range interaction to large scattering lengths. Then this renormalized interaction is applied to many-body theories to determined those universal relations of the system. From the few-body perspective, we discuss the scattering between atoms in a single-color radio-frequency field. Our motivation is proposing the radio-frequency field as an effective tool to control interactions between cold atoms. Such a technique may be useful in future experiments such as creating phase transitions in spinor condensates. We also discuss the formation of ultracold molecules using radio-freqency fields from a time-dependent approach.

Phase properties of elastic waves in systems constituted of adsorbed diatomic molecules on the (001) surface of a simple cubic crystal

NASA Astrophysics Data System (ADS)

Deymier, P. A.; Runge, K.

2018-03-01

A Green's function-based numerical method is developed to calculate the phase of scattered elastic waves in a harmonic model of diatomic molecules adsorbed on the (001) surface of a simple cubic crystal. The phase properties of scattered waves depend on the configuration of the molecules. The configurations of adsorbed molecules on the crystal surface such as parallel chain-like arrays coupled via kinks are used to demonstrate not only linear but also non-linear dependency of the phase on the number of kinks along the chains. Non-linear behavior arises for scattered waves with frequencies in the vicinity of a diatomic molecule resonance. In the non-linear regime, the variation in phase with the number of kinks is formulated mathematically as unitary matrix operations leading to an analogy between phase-based elastic unitary operations and quantum gates. The advantage of elastic based unitary operations is that they are easily realizable physically and measurable.

The Eightfold Way: A Theory of Strong Interaction Symmetry

DOE R&D Accomplishments Database

Gell-Mann, M.

1961-03-15

A new model of the higher symmetry of elementary particles is introduced ln which the eight known baryons are treated as a supermultiplet, degenerate in the limit of unitary symmetry but split into isotopic spin multiplets by a symmetry-breaking term. The symmetry violation is ascribed phenomenologically to the mass differences. The baryons correspond to an eight-dimensional irreducible representation of the unitary group. The pion and K meson fit into a similar set of eight particles along with a predicted pseudoscalar meson X {sup o} having I = 0. A ninth vector meson coupled to the baryon current can be accommodated naturally in the scheme. It is predicted that the eight baryons should all have the same spin and parity and that pseudoscalar and vector mesons should form octets with possible additional singlets. The mathematics of the unitary group is described by considering three fictitious leptons, nu , e {sup -}, and mu {sup -}, which may throw light on the structure of weak interactions. (D. L.C.)

Decay of random correlation functions for unimodal maps

NASA Astrophysics Data System (ADS)

Baladi, Viviane; Benedicks, Michael; Maume-Deschamps, Véronique

2000-10-01

Since the pioneering results of Jakobson and subsequent work by Benedicks-Carleson and others, it is known that quadratic maps tfa( χ) = a - χ2 admit a unique absolutely continuous invariant measure for a positive measure set of parameters a. For topologically mixing tfa, Young and Keller-Nowicki independently proved exponential decay of correlation functions for this a.c.i.m. and smooth observables. We consider random compositions of small perturbations tf + ωt, with tf = tfa or another unimodal map satisfying certain nonuniform hyperbolicity axioms, and ωt chosen independently and identically in [-ɛ, ɛ]. Baladi-Viana showed exponential mixing of the associated Markov chain, i.e., averaging over all random itineraries. We obtain stretched exponential bounds for the random correlation functions of Lipschitz observables for the sample measure μωof almost every itinerary.

Using ArcMap, Google Earth, and Global Positioning Systems to select and locate random households in rural Haiti.

PubMed

Wampler, Peter J; Rediske, Richard R; Molla, Azizur R

2013-01-18

A remote sensing technique was developed which combines a Geographic Information System (GIS); Google Earth, and Microsoft Excel to identify home locations for a random sample of households in rural Haiti. The method was used to select homes for ethnographic and water quality research in a region of rural Haiti located within 9 km of a local hospital and source of health education in Deschapelles, Haiti. The technique does not require access to governmental records or ground based surveys to collect household location data and can be performed in a rapid, cost-effective manner. The random selection of households and the location of these households during field surveys were accomplished using GIS, Google Earth, Microsoft Excel, and handheld Garmin GPSmap 76CSx GPS units. Homes were identified and mapped in Google Earth, exported to ArcMap 10.0, and a random list of homes was generated using Microsoft Excel which was then loaded onto handheld GPS units for field location. The development and use of a remote sensing method was essential to the selection and location of random households. A total of 537 homes initially were mapped and a randomized subset of 96 was identified as potential survey locations. Over 96% of the homes mapped using Google Earth imagery were correctly identified as occupied dwellings. Only 3.6% of the occupants of mapped homes visited declined to be interviewed. 16.4% of the homes visited were not occupied at the time of the visit due to work away from the home or market days. A total of 55 households were located using this method during the 10 days of fieldwork in May and June of 2012. The method used to generate and field locate random homes for surveys and water sampling was an effective means of selecting random households in a rural environment lacking geolocation infrastructure. The success rate for locating households using a handheld GPS was excellent and only rarely was local knowledge required to identify and locate households. This method provides an important technique that can be applied to other developing countries where a randomized study design is needed but infrastructure is lacking to implement more traditional participant selection methods.

Minimal unitary representation of 5d superconformal algebra F(4) and AdS 6/CFT 5 higher spin (super)-algebras

DOE PAGES

Fernando, Sudarshan; Günaydin, Murat

2014-11-28

We study the minimal unitary representation (minrep) of SO(5, 2), obtained by quantization of its geometric quasiconformal action, its deformations and supersymmetric extensions. The minrep of SO(5, 2) describes a massless conformal scalar field in five dimensions and admits a unique “deformation” which describes a massless conformal spinor. Scalar and spinor minreps of SO(5, 2) are the 5d analogs of Dirac’s singletons of SO(3, 2). We then construct the minimal unitary representation of the unique 5d supercon-formal algebra F(4) with the even subalgebra SO(5, 2) ×SU(2). The minrep of F(4) describes a massless conformal supermultiplet consisting of two scalar andmore » one spinor fields. We then extend our results to the construction of higher spin AdS 6/CFT 5 (super)-algebras. The Joseph ideal of the minrep of SO(5, 2) vanishes identically as operators and hence its enveloping algebra yields the AdS 6/CFT 5 bosonic higher spin algebra directly. The enveloping algebra of the spinor minrep defines a “deformed” higher spin algebra for which a deformed Joseph ideal vanishes identically as operators. These results are then extended to the construction of the unique higher spin AdS 6/CFT 5 superalgebra as the enveloping algebra of the minimal unitary realization of F(4) obtained by the quasiconformal methods.« less

Transition and Damping of Collective Modes in a Trapped Fermi Gas between BCS and Unitary Limits near the Phase Transition

PubMed Central

Dong, Hang; Zhang, Wenyuan; Zhou, Li; Ma, Yongli

2015-01-01

We investigate the transition and damping of low-energy collective modes in a trapped unitary Fermi gas by solving the Boltzmann-Vlasov kinetic equation in a scaled form, which is combined with both the T-matrix fluctuation theory in normal phase and the mean-field theory in order phase. In order to connect the microscopic and kinetic descriptions of many-body Feshbach scattering, we adopt a phenomenological two-fluid physical approach, and derive the coupling constants in the order phase. By solving the Boltzmann-Vlasov steady-state equation in a variational form, we calculate two viscous relaxation rates with the collision probabilities of fermion’s scattering including fermions in the normal fluid and fermion pairs in the superfluid. Additionally, by considering the pairing and depairing of fermions, we get results of the frequency and damping of collective modes versus temperature and s-wave scattering length. Our theoretical results are in a remarkable agreement with the experimental data, particularly for the sharp transition between collisionless and hydrodynamic behaviour and strong damping between BCS and unitary limits near the phase transition. The sharp transition originates from the maximum of viscous relaxation rate caused by fermion-fermion pair collision at the phase transition point when the fermion depair, while the strong damping due to the fast varying of the frequency of collective modes from BCS limit to unitary limit. PMID:26522094

Quantum control and measurement of atomic spins in polarization spectroscopy

NASA Astrophysics Data System (ADS)

Deutsch, Ivan H.; Jessen, Poul S.

2010-03-01

Quantum control and measurement are two sides of the same coin. To affect a dynamical map, well-designed time-dependent control fields must be applied to the system of interest. To read out the quantum state, information about the system must be transferred to a probe field. We study a particular example of this dual action in the context of quantum control and measurement of atomic spins through the light-shift interaction with an off-resonant optical probe. By introducing an irreducible tensor decomposition, we identify the coupling of the Stokes vector of the light field with moments of the atomic spin state. This shows how polarization spectroscopy can be used for continuous weak measurement of atomic observables that evolve as a function of time. Simultaneously, the state-dependent light shift induced by the probe field can drive nonlinear dynamics of the spin, and can be used to generate arbitrary unitary transformations on the atoms. We revisit the derivation of the master equation in order to give a unified description of spin dynamics in the presence of both nonlinear dynamics and photon scattering. Based on this formalism, we review applications to quantum control, including the design of state-to-state mappings, and quantum-state reconstruction via continuous weak measurement on a dynamically controlled ensemble.

Robust PRNG based on homogeneously distributed chaotic dynamics

NASA Astrophysics Data System (ADS)

Garasym, Oleg; Lozi, René; Taralova, Ina

2016-02-01

This paper is devoted to the design of new chaotic Pseudo Random Number Generator (CPRNG). Exploring several topologies of network of 1-D coupled chaotic mapping, we focus first on two dimensional networks. Two topologically coupled maps are studied: TTL rc non-alternate, and TTL SC alternate. The primary idea of the novel maps has been based on an original coupling of the tent and logistic maps to achieve excellent random properties and homogeneous /uniform/ density in the phase plane, thus guaranteeing maximum security when used for chaos base cryptography. In this aim two new nonlinear CPRNG: MTTL 2 sc and NTTL 2 are proposed. The maps successfully passed numerous statistical, graphical and numerical tests, due to proposed ring coupling and injection mechanisms.

Improving diagnostic accuracy of prostate carcinoma by systematic random map-biopsy.

PubMed

Szabó, J; Hegedûs, G; Bartók, K; Kerényi, T; Végh, A; Romics, I; Szende, B

2000-01-01

Systematic random rectal ultrasound directed map-biopsy of the prostate was performed in 77 RDE (rectal digital examination) positive and 25 RDE negative cases, if applicable. Hypoechoic areas were found in 30% of RDE positive and in 16% of RDE negative cases. The score for carcinoma in the hypoechoic areas was 6.5% in RDE positive and 0% in RDE negative cases, whereas systematic map biopsy detected 62% carcinomas in RDE positive, and 16% carcinomas in RDE negative patients. The probability of positive diagnosis of prostate carcinoma increased in parallel with the number of biopsy samples/case. The importance of systematic map biopsy is emphasized.

The relationship between buccofacial and limb apraxia.

PubMed

Raade, A S; Rothi, L J; Heilman, K M

1991-07-01

There are at least two possible models depicting the relationship between buccofacial and limb apraxia. First, apraxia can be viewed as a unitary motor disorder which transcends the output modalities of both buccofacial and limb output. A high degree of similarity between the two types of apraxia would support this model. Alternatively, the relationship between buccofacial and limb apraxia may not include a unitary mechanism. The presence of quantitative and qualitative differences between buccofacial and limb performance would support this nonunitary model. The results of the present study support the nonunitary model.

Nuclei and the Unitary Limit

NASA Astrophysics Data System (ADS)

Hammer, H.-W.

2018-07-01

Few-body systems with large scattering length display universal properties which are independent of the details of short-distance dynamics. These features include universal correlations between few-body observables and a geometric spectrum of three- and higher-body bound states. They can be observed in a wide range of systems from ultracold atoms to hadrons and nuclei. In this contribution, we review universality in nuclei dominated by few-body physics. In particular, we discuss halo nuclei and the description of light nuclei in a strict expansion around the unitary limit of infinite scattering length.

On the integration of a class of nonlinear systems of ordinary differential equations

NASA Astrophysics Data System (ADS)

Talyshev, Aleksandr A.

2017-11-01

For each associative, commutative, and unitary algebra over the field of real or complex numbers and an integrable nonlinear ordinary differential equation we can to construct integrable systems of ordinary differential equations and integrable systems of partial differential equations. In this paper we consider in some sense the inverse problem. Determine the conditions under which a given system of ordinary differential equations can be represented as a differential equation in some associative, commutative and unitary algebra. It is also shown that associativity is not a necessary condition.

Introducing electron capture into the unitary-convolution-approximation energy-loss theory at low velocities

NASA Astrophysics Data System (ADS)

Schiwietz, G.; Grande, P. L.

2011-11-01

Recent developments in the theoretical treatment of electronic energy losses of bare and screened ions in gases are presented. Specifically, the unitary-convolution-approximation (UCA) stopping-power model has proven its strengths for the determination of nonequilibrium effects for light as well as heavy projectiles at intermediate to high projectile velocities. The focus of this contribution will be on the UCA and its extension to specific projectile energies far below 100 keV/u, by considering electron-capture contributions at charge-equilibrium conditions.

Schwarzschild fuzzball and explicitly unitary Hawking radiation

NASA Astrophysics Data System (ADS)

Zeng, Ding-fang

2018-05-01

We provide a fuzzball picture for Schwarzschild black holes, in which matters and energy consisting the hole are not positioned on the central point exclusively but oscillate around there in a serial of eigen-modes, each of which features a special level of binding degrees and are quantum mechanically possible to be measured outside the horizon. By listing these modes explicitly for holes as large as 6Mpl, we find that their number increases exponentially with the area. Basing on these results, we construct a simple but explicitly unitary formulation of Hawking radiations.

Two-dimensional RCFT's without Kac-Moody symmetry

NASA Astrophysics Data System (ADS)

Hampapura, Harsha R.; Mukhi, Sunil

2016-07-01

Using the method of modular-invariant differential equations, we classify a family of Rational Conformal Field Theories with two and three characters having no Kac-Moody algebra. In addition to unitary and non-unitary minimal models, we find "dual" theories whose characters obey bilinear relations with those of the minimal models to give the Moonshine Module. In some ways this relation is analogous to cosets of meromorphic CFT's. The theory dual in this sense to the Ising model has central charge 47/2 and is related to the Baby Monster Module.

Unitary subsector of generalized minimal models

NASA Astrophysics Data System (ADS)

Behan, Connor

2018-05-01

We revisit the line of nonunitary theories that interpolate between the Virasoro minimal models. Numerical bootstrap applications have brought about interest in the four-point function involving the scalar primary of lowest dimension. Using recent progress in harmonic analysis on the conformal group, we prove the conjecture that global conformal blocks in this correlator appear with positive coefficients. We also compute many such coefficients in the simplest mixed correlator system. Finally, we comment on the status of using global conformal blocks to isolate the truly unitary points on this line.

Study of optical techniques for the Ames unitary wind tunnels. Part 1: Schlieren

NASA Technical Reports Server (NTRS)

Lee, George

1992-01-01

Alignment procedures and conceptual designs for the rapid alignment of the Ames Unitary Wind Tunnel schlieren systems were devised. The schlieren systems can be aligned by translating the light source, the mirrors, and the knife edge equal distances. One design for rapid alignment consists of a manual pin locking scheme. The other is a motorized electronic position scheme. A study of two optical concepts which can be used with the schlieren system was made. These are the 'point diffraction interferometers' and the 'focus schlieren'. Effects of vibrations were studied.

Disordered two-dimensional electron systems with chiral symmetry

NASA Astrophysics Data System (ADS)

Markoš, P.; Schweitzer, L.

2012-10-01

We review the results of our recent numerical investigations on the electronic properties of disordered two dimensional systems with chiral unitary, chiral orthogonal, and chiral symplectic symmetry. Of particular interest is the behavior of the density of states and the logarithmic scaling of the smallest Lyapunov exponents in the vicinity of the chiral quantum critical point in the band center at E=0. The observed peaks or depressions in the density of states, the distribution of the critical conductances, and the possible non-universality of the critical exponents for certain chiral unitary models are discussed.

A Unitary-Transformative Nursing Science: From Angst to Appreciation.

PubMed

Cowling, W Richard

2017-10-01

The discord within nursing regarding the definition of nursing science has created great angst, particularly for those who view nursing science as a body of knowledge derived from theories specific to its unique concerns. The purpose of this brief article is to suggest a perspective and process grounded in appreciation of wholeness that may offer a way forward for proponents of a unitary-transformative nursing science that transcends the discord. This way forward is guided by principles of fostering dissent without contempt, generating a well-imagined future, and garnering appreciatively inspired action for change.

Extending matchgates into universal quantum computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brod, Daniel J.; Galvao, Ernesto F.

2011-08-15

Matchgates are a family of two-qubit gates associated with noninteracting fermions. They are classically simulatable if acting only on nearest neighbors but become universal for quantum computation if we relax this restriction or use swap gates [Jozsa and Miyake, Proc. R. Soc. A 464, 3089 (2008)]. We generalize this result by proving that any nonmatchgate parity-preserving unitary is capable of extending the computational power of matchgates into universal quantum computation. We identify the single local invariant of parity-preserving unitaries responsible for this, and discuss related results in the context of fermionic systems.

Local unitary representation of braids and N-qubit entanglements

NASA Astrophysics Data System (ADS)

Yu, Li-Wei

2018-03-01

In this paper, by utilizing the idea of stabilizer codes, we give some relationships between one local unitary representation of braid group in N-qubit tensor space and the corresponding entanglement properties of the N-qubit pure state |Ψ >, where the N-qubit state |Ψ > is obtained by applying the braiding operation on the natural basis. Specifically, we show that the separability of |Ψ > =B|0> ^{⊗ N} is closely related to the diagrammatic version of the braid operator B. This may provide us more insights about the topological entanglement and quantum entanglement.

Comparison of RAPD Linkage Maps Constructed For a Single Longleaf Pine From Both Haploid and Diploid Mapping Populations

Treesearch

Thomas L. Kubisiak; C.Dana Nelson; W.L. Name; M. Stine

1996-01-01

Considerable concern has been voiced regarding the reproducibility/transferability of RAPD markers across different genetic backgrounds in genetic mapping experiments. Therefore, separate gametic subsets (mapping populations) were used to construct individual random amplified polymorphic DNA (RAPD) linkage maps for a single longleaf pine (Pinus palustris...

Functional form for the leading correction to the distribution of the largest eigenvalue in the GUE and LUE

NASA Astrophysics Data System (ADS)

Forrester, Peter J.; Trinh, Allan K.

2018-05-01

The neighbourhood of the largest eigenvalue λmax in the Gaussian unitary ensemble (GUE) and Laguerre unitary ensemble (LUE) is referred to as the soft edge. It is known that there exists a particular centring and scaling such that the distribution of λmax tends to a universal form, with an error term bounded by 1/N2/3. We take up the problem of computing the exact functional form of the leading error term in a large N asymptotic expansion for both the GUE and LUE—two versions of the LUE are considered, one with the parameter a fixed and the other with a proportional to N. Both settings in the LUE case allow for an interpretation in terms of the distribution of a particular weighted path length in a model involving exponential variables on a rectangular grid, as the grid size gets large. We give operator theoretic forms of the corrections, which are corollaries of knowledge of the first two terms in the large N expansion of the scaled kernel and are readily computed using a method due to Bornemann. We also give expressions in terms of the solutions of particular systems of coupled differential equations, which provide an alternative method of computation. Both characterisations are well suited to a thinned generalisation of the original ensemble, whereby each eigenvalue is deleted independently with probability (1 - ξ). In Sec. V, we investigate using simulation the question of whether upon an appropriate centring and scaling a wider class of complex Hermitian random matrix ensembles have their leading correction to the distribution of λmax proportional to 1/N2/3.

A global solution to the Schrödinger equation: From Henstock to Feynman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nathanson, Ekaterina S., E-mail: enathanson@ggc.edu; Jørgensen, Palle E. T., E-mail: palle-jorgensen@uiowa.edu

2015-09-15

One of the key elements of Feynman’s formulation of non-relativistic quantum mechanics is a so-called Feynman path integral. It plays an important role in the theory, but it appears as a postulate based on intuition, rather than a well-defined object. All previous attempts to supply Feynman’s theory with rigorous mathematics underpinning, based on the physical requirements, have not been satisfactory. The difficulty comes from the need to define a measure on the infinite dimensional space of paths and to create an integral that would possess all of the properties requested by Feynman. In the present paper, we consider a newmore » approach to defining the Feynman path integral, based on the theory developed by Muldowney [A Modern Theory of Random Variable: With Applications in Stochastic Calcolus, Financial Mathematics, and Feynman Integration (John Wiley & Sons, Inc., New Jersey, 2012)]. Muldowney uses the Henstock integration technique and deals with non-absolute integrability of the Fresnel integrals, in order to obtain a representation of the Feynman path integral as a functional. This approach offers a mathematically rigorous definition supporting Feynman’s intuitive derivations. But in his work, Muldowney gives only local in space-time solutions. A physical solution to the non-relativistic Schrödinger equation must be global, and it must be given in the form of a unitary one-parameter group in L{sup 2}(ℝ{sup n}). The purpose of this paper is to show that a system of one-dimensional local Muldowney’s solutions may be extended to yield a global solution. Moreover, the global extension can be represented by a unitary one-parameter group acting in L{sup 2}(ℝ{sup n})« less

Icezones instead of firewalls: extended entanglement beyond the event horizon and unitary evaporation of a black hole

NASA Astrophysics Data System (ADS)

Hutchinson, John; Stojkovic, Dejan

2016-07-01

We examine the basic assumptions in the original setup of the firewall paradox. The main claim is that a single mode of the lathe radiation is maximally entangled with the mode inside the horizon and simultaneously with the modes of early Hawking radiation. We argue that this situation never happens during the evolution of a black hole. Quantum mechanics tells us that while the black hole exists, unitary evolution maximally entangles a late mode located just outside the horizon with a combination of early radiation and black hole states, instead of either of them separately. One of the reasons for this is that the black hole radiation is not random and strongly depends on the geometry and charge of the black hole, as detailed numerical calculations of Hawking evaporation clearly show. As a consequence, one can not factor out the state of the black hole. However, this extended entanglement between the black hole and modes of early and late radiation indicates that, as the black hole ages, the local Rindler horizon is modified out to macroscopic distances from the black hole. Fundamentally non-local physics nor firewalls are not necessary to explain this result. We propose an infrared mechanism called icezone that is mediated by low energy interacting modes and acts near any event horizon to entangle states separated by long distances. These interactions at first provide small corrections to the thermal Hawking radiation. At the end of evaporation however the effect of interactions is as large as the Hawking radiation and information is recovered for an outside observer. We verify this in an explicit construction and calculation of the density matrix of a spin model.

A study of the feasibility of introducing therapeutic touch into the operative environment with patients undergoing cerebral angiography.

PubMed

Madrid, Mary M; Barrett, Elizabeth A M; Winstead-Fry, Patricia

2010-09-01

The purpose of this pilot study was to determine whether Therapeutic Touch (TT) can be effectively used in the operative setting and whether it could produce positive outcomes in the period from cerebral angiography to discharge. The specific outcomes to be assessed were blood pressure, pulse, and respirations. TT is an intervention that involves the intentional direction of energy for the purpose of healing. The present study was developed within the conceptual framework of Rogers's model of unitary human beings. Data were collected at a center for endovascular surgery. The participants were 40 men and women aged between 18 and 80 years who were referred to the center for cerebral angiograms. The participants were English-speaking, ambulatory patients, with no history of prior cerebral angiograms and no psychiatric diagnosis. The design was a randomized, single-blind experiment. The research data were collected in the normal course of the angiogram procedure and recovery room. The blood pressure, pulse, and respirations were routinely noted before, during, and after the procedure. The study was significant in three aspects: (a) it was the first study to develop a protocol for delivering TT in the preoperative course of neurological patients, (b) the study is conceptualized within Rogers's conceptual model of unitary human beings, and (c) the study explored the impact of TT on selected outcomes in endovascular patients. A protocol for delivering TT in the operative setting was successfully developed and implemented. The efficacy of TT on the blood pressure, respirations, and pulse of the experimental group was not statistically significant. The reasons for this finding are explored, and suggestions are made for future research.

Mapping ecological systems with a random foret model: tradeoffs between errors and bias

Treesearch

Emilie Grossmann; Janet Ohmann; James Kagan; Heather May; Matthew Gregory

2010-01-01

New methods for predictive vegetation mapping allow improved estimations of plant community composition across large regions. Random Forest (RF) models limit over-fitting problems of other methods, and are known for making accurate classification predictions from noisy, nonnormal data, but can be biased when plot samples are unbalanced. We developed two contrasting...

Hurwitz numbers and products of random matrices

NASA Astrophysics Data System (ADS)

Orlov, A. Yu.

2017-09-01

We study multimatrix models, which may be viewed as integrals of products of tau functions depending on the eigenvalues of products of random matrices. We consider tau functions of the two-component Kadomtsev-Petviashvili (KP) hierarchy (semi-infinite relativistic Toda lattice) and of the B-type KP (BKP) hierarchy introduced by Kac and van de Leur. Such integrals are sometimes tau functions themselves. We consider models that generate Hurwitz numbers HE,F, where E is the Euler characteristic of the base surface and F is the number of branch points. We show that in the case where the integrands contain the product of n > 2 matrices, the integral generates Hurwitz numbers with E ≤ 2 and F ≤ n+2. Both the numbers E and F depend both on n and on the order of the factors in the matrix product. The Euler characteristic E can be either an even or an odd number, i.e., it can match both orientable and nonorientable (Klein) base surfaces depending on the presence of the tau function of the BKP hierarchy in the integrand. We study two cases, the products of complex and the products of unitary matrices.

Unitary cocycle representations of the Galilean line group: Quantum mechanical principle of equivalence

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacGregor, B.R.; McCoy, A.E.; Wickramasekara, S., E-mail: wickrama@grinnell.edu

2012-09-15

We present a formalism of Galilean quantum mechanics in non-inertial reference frames and discuss its implications for the equivalence principle. This extension of quantum mechanics rests on the Galilean line group, the semidirect product of the real line and the group of analytic functions from the real line to the Euclidean group in three dimensions. This group provides transformations between all inertial and non-inertial reference frames and contains the Galilei group as a subgroup. We construct a certain class of unitary representations of the Galilean line group and show that these representations determine the structure of quantum mechanics in non-inertialmore » reference frames. Our representations of the Galilean line group contain the usual unitary projective representations of the Galilei group, but have a more intricate cocycle structure. The transformation formula for the Hamiltonian under the Galilean line group shows that in a non-inertial reference frame it acquires a fictitious potential energy term that is proportional to the inertial mass, suggesting the equivalence of inertial mass and gravitational mass in quantum mechanics. - Highlights: Black-Right-Pointing-Pointer A formulation of Galilean quantum mechanics in non-inertial reference frames is given. Black-Right-Pointing-Pointer The key concept is the Galilean line group, an infinite dimensional group. Black-Right-Pointing-Pointer Unitary, cocycle representations of the Galilean line group are constructed. Black-Right-Pointing-Pointer A non-central extension of the group underlies these representations. Black-Right-Pointing-Pointer Quantum equivalence principle and gravity emerge from these representations.« less

Predicting temperate forest stand types using only structural profiles from discrete return airborne lidar

NASA Astrophysics Data System (ADS)

Fedrigo, Melissa; Newnham, Glenn J.; Coops, Nicholas C.; Culvenor, Darius S.; Bolton, Douglas K.; Nitschke, Craig R.

2018-02-01

Light detection and ranging (lidar) data have been increasingly used for forest classification due to its ability to penetrate the forest canopy and provide detail about the structure of the lower strata. In this study we demonstrate forest classification approaches using airborne lidar data as inputs to random forest and linear unmixing classification algorithms. Our results demonstrated that both random forest and linear unmixing models identified a distribution of rainforest and eucalypt stands that was comparable to existing ecological vegetation class (EVC) maps based primarily on manual interpretation of high resolution aerial imagery. Rainforest stands were also identified in the region that have not previously been identified in the EVC maps. The transition between stand types was better characterised by the random forest modelling approach. In contrast, the linear unmixing model placed greater emphasis on field plots selected as endmembers which may not have captured the variability in stand structure within a single stand type. The random forest model had the highest overall accuracy (84%) and Cohen's kappa coefficient (0.62). However, the classification accuracy was only marginally better than linear unmixing. The random forest model was applied to a region in the Central Highlands of south-eastern Australia to produce maps of stand type probability, including areas of transition (the 'ecotone') between rainforest and eucalypt forest. The resulting map provided a detailed delineation of forest classes, which specifically recognised the coalescing of stand types at the landscape scale. This represents a key step towards mapping the structural and spatial complexity of these ecosystems, which is important for both their management and conservation.

Quantum Jarzynski equality of measurement-based work extraction

NASA Astrophysics Data System (ADS)

Morikuni, Yohei; Tajima, Hiroyasu; Hatano, Naomichi

2017-03-01

Many studies of quantum-size heat engines assume that the dynamics of an internal system is unitary and that the extracted work is equal to the energy loss of the internal system. Both assumptions, however, should be under scrutiny. In the present paper, we analyze quantum-scale heat engines, employing the measurement-based formulation of the work extraction recently introduced by Hayashi and Tajima [M. Hayashi and H. Tajima, arXiv:1504.06150]. We first demonstrate the inappropriateness of the unitary time evolution of the internal system (namely, the first assumption above) using a simple two-level system; we show that the variance of the energy transferred to an external system diverges when the dynamics of the internal system is approximated to a unitary time evolution. Second, we derive the quantum Jarzynski equality based on the formulation of Hayashi and Tajima as a relation for the work measured by an external macroscopic apparatus. The right-hand side of the equality reduces to unity for "natural" cyclic processes but fluctuates wildly for noncyclic ones, exceeding unity often. This fluctuation should be detectable in experiments and provide evidence for the present formulation.

{{SO(d,1)}}-Invariant Yang-Baxter Operators and the dS/CFT Correspondence

NASA Astrophysics Data System (ADS)

Hollands, Stefan; Lechner, Gandalf

2018-01-01

We propose a model for the dS/CFT correspondence. The model is constructed in terms of a "Yang-Baxter operator" R for unitary representations of the de Sitter group {SO(d,1)}. This R-operator is shown to satisfy the Yang-Baxter equation, unitarity, as well as certain analyticity relations, including in particular a crossing symmetry. With the aid of this operator we construct: (a) a chiral (light-ray) conformal quantum field theory whose internal degrees of freedom transform under the given unitary representation of {SO(d,1)}. By analogy with the O( N) non-linear sigma model, this chiral CFT can be viewed as propagating in a de Sitter spacetime. (b) A (non-unitary) Euclidean conformal quantum field theory on R}^{d-1, where SO( d, 1) now acts by conformal transformations in (Euclidean) spacetime. These two theories can be viewed as dual to each other if we interpret R}^{d-1 as conformal infinity of de Sitter spacetime. Our constructions use semi-local generator fields defined in terms of R and abstract methods from operator algebras.

Adiabatic quantum computation along quasienergies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Atushi; Nemoto, Kae; National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda ku, Tokyo 101-8430

2010-02-15

The parametric deformations of quasienergies and eigenvectors of unitary operators are applied to the design of quantum adiabatic algorithms. The conventional, standard adiabatic quantum computation proceeds along eigenenergies of parameter-dependent Hamiltonians. By contrast, discrete adiabatic computation utilizes adiabatic passage along the quasienergies of parameter-dependent unitary operators. For example, such computation can be realized by a concatenation of parameterized quantum circuits, with an adiabatic though inevitably discrete change of the parameter. A design principle of adiabatic passage along quasienergy was recently proposed: Cheon's quasienergy and eigenspace anholonomies on unitary operators is available to realize anholonomic adiabatic algorithms [A. Tanaka and M.more » Miyamoto, Phys. Rev. Lett. 98, 160407 (2007)], which compose a nontrivial family of discrete adiabatic algorithms. It is straightforward to port a standard adiabatic algorithm to an anholonomic adiabatic one, except an introduction of a parameter |v>, which is available to adjust the gaps of the quasienergies to control the running time steps. In Grover's database search problem, the costs to prepare |v> for the qualitatively different (i.e., power or exponential) running time steps are shown to be qualitatively different.« less

Spatial evolution of quantum mechanical states

NASA Astrophysics Data System (ADS)

Christensen, N. D.; Unger, J. E.; Pinto, S.; Su, Q.; Grobe, R.

2018-02-01

The time-dependent Schrödinger equation is solved traditionally as an initial-time value problem, where its solution is obtained by the action of the unitary time-evolution propagator on the quantum state that is known at all spatial locations but only at t = 0. We generalize this approach by examining the spatial evolution from a state that is, by contrast, known at all times t, but only at one specific location. The corresponding spatial-evolution propagator turns out to be pseudo-unitary. In contrast to the real energies that govern the usual (unitary) time evolution, the spatial evolution can therefore require complex phases associated with dynamically relevant solutions that grow exponentially. By introducing a generalized scalar product, for which the spatial generator is Hermitian, one can show that the temporal integral over the probability current density is spatially conserved, in full analogy to the usual norm of the state, which is temporally conserved. As an application of the spatial propagation formalism, we introduce a spatial backtracking technique that permits us to reconstruct any quantum information about an atom from the ionization data measured at a detector outside the interaction region.

Complex Instruction Set Quantum Computing

NASA Astrophysics Data System (ADS)

Sanders, G. D.; Kim, K. W.; Holton, W. C.

1998-03-01

In proposed quantum computers, electromagnetic pulses are used to implement logic gates on quantum bits (qubits). Gates are unitary transformations applied to coherent qubit wavefunctions and a universal computer can be created using a minimal set of gates. By applying many elementary gates in sequence, desired quantum computations can be performed. This reduced instruction set approach to quantum computing (RISC QC) is characterized by serial application of a few basic pulse shapes and a long coherence time. However, the unitary matrix of the overall computation is ultimately a unitary matrix of the same size as any of the elementary matrices. This suggests that we might replace a sequence of reduced instructions with a single complex instruction using an optimally taylored pulse. We refer to this approach as complex instruction set quantum computing (CISC QC). One trades the requirement for long coherence times for the ability to design and generate potentially more complex pulses. We consider a model system of coupled qubits interacting through nearest neighbor coupling and show that CISC QC can reduce the time required to perform quantum computations.

Quantum Jarzynski equality of measurement-based work extraction.

PubMed

Morikuni, Yohei; Tajima, Hiroyasu; Hatano, Naomichi

2017-03-01

Many studies of quantum-size heat engines assume that the dynamics of an internal system is unitary and that the extracted work is equal to the energy loss of the internal system. Both assumptions, however, should be under scrutiny. In the present paper, we analyze quantum-scale heat engines, employing the measurement-based formulation of the work extraction recently introduced by Hayashi and Tajima [M. Hayashi and H. Tajima, arXiv:1504.06150]. We first demonstrate the inappropriateness of the unitary time evolution of the internal system (namely, the first assumption above) using a simple two-level system; we show that the variance of the energy transferred to an external system diverges when the dynamics of the internal system is approximated to a unitary time evolution. Second, we derive the quantum Jarzynski equality based on the formulation of Hayashi and Tajima as a relation for the work measured by an external macroscopic apparatus. The right-hand side of the equality reduces to unity for "natural" cyclic processes but fluctuates wildly for noncyclic ones, exceeding unity often. This fluctuation should be detectable in experiments and provide evidence for the present formulation.

Quantum jump from singularity to outside of black hole

NASA Astrophysics Data System (ADS)

Dündar, Furkan Semih; Hajian, Kamal

2016-02-01

Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as a part of his spacetime, then the semi-classical evolution would be non-unitary as viewed by him. Specifically, a free-falling observer inside the black hole would have a Hilbert space with non-unitary evolution; a quantum jump for particles encountering the singularity to outside of the horizon as late Hawking radiations. The non-unitarity in the jump resembles the one in collapse of wave function, but preserves entanglements. Accordingly, we elaborate the first postulate of black hole complementarity: freely falling observers who pass through the event horizon would have non-unitary evolution, while it does not have physically measurable effects for them. Besides, no information would be lost in the singularity. Taking the modified picture into account, the firewall paradox can be resolved, respecting No Drama. A by-product of our modification is that roughly half of the entropy of the black hole is released close to the end of evaporation in the shape of very hot Hawking radiation.

A self-consistency check for unitary propagation of Hawking quanta

NASA Astrophysics Data System (ADS)

Baker, Daniel; Kodwani, Darsh; Pen, Ue-Li; Yang, I.-Sheng

2017-11-01

The black hole information paradox presumes that quantum field theory in curved space-time can provide unitary propagation from a near-horizon mode to an asymptotic Hawking quantum. Instead of invoking conjectural quantum-gravity effects to modify such an assumption, we propose a self-consistency check. We establish an analogy to Feynman’s analysis of a double-slit experiment. Feynman showed that unitary propagation of the interfering particles, namely ignoring the entanglement with the double-slit, becomes an arbitrarily reliable assumption when the screen upon which the interference pattern is projected is infinitely far away. We argue for an analogous self-consistency check for quantum field theory in curved space-time. We apply it to the propagation of Hawking quanta and test whether ignoring the entanglement with the geometry also becomes arbitrarily reliable in the limit of a large black hole. We present curious results to suggest a negative answer, and we discuss how this loss of naive unitarity in QFT might be related to a solution of the paradox based on the soft-hair-memory effect.

Hand pose estimation in depth image using CNN and random forest

NASA Astrophysics Data System (ADS)

Chen, Xi; Cao, Zhiguo; Xiao, Yang; Fang, Zhiwen

2018-03-01

Thanks to the availability of low cost depth cameras, like Microsoft Kinect, 3D hand pose estimation attracted special research attention in these years. Due to the large variations in hand`s viewpoint and the high dimension of hand motion, 3D hand pose estimation is still challenging. In this paper we propose a two-stage framework which joint with CNN and Random Forest to boost the performance of hand pose estimation. First, we use a standard Convolutional Neural Network (CNN) to regress the hand joints` locations. Second, using a Random Forest to refine the joints from the first stage. In the second stage, we propose a pyramid feature which merges the information flow of the CNN. Specifically, we get the rough joints` location from first stage, then rotate the convolutional feature maps (and image). After this, for each joint, we map its location to each feature map (and image) firstly, then crop features at each feature map (and image) around its location, put extracted features to Random Forest to refine at last. Experimentally, we evaluate our proposed method on ICVL dataset and get the mean error about 11mm, our method is also real-time on a desktop.

Origin of fine structure of the giant dipole resonance in s d -shell nuclei

NASA Astrophysics Data System (ADS)

Fearick, R. W.; Erler, B.; Matsubara, H.; von Neumann-Cosel, P.; Richter, A.; Roth, R.; Tamii, A.

2018-04-01

A set of high-resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the giant dipole resonance (GDR) in s d -shell nuclei. Understanding is achieved by comparison with random phase approximation calculations for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows one to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement for scales in the range of a few hundred keV supports the surmise that the fine structure arises from ground-state deformation driven by α clustering.

Multi-party Semi-quantum Key Agreement with Delegating Quantum Computation

NASA Astrophysics Data System (ADS)

Liu, Wen-Jie; Chen, Zhen-Yu; Ji, Sai; Wang, Hai-Bin; Zhang, Jun

2017-10-01

A multi-party semi-quantum key agreement (SQKA) protocol based on delegating quantum computation (DQC) model is proposed by taking Bell states as quantum resources. In the proposed protocol, the participants only need the ability of accessing quantum channel and preparing single photons {|0〉, |1〉, |+〉, |-〉}, while the complicated quantum operations, such as the unitary operations and Bell measurement, will be delegated to the remote quantum center. Compared with previous quantum key agreement protocols, this client-server model is more feasible in the early days of the emergence of quantum computers. In order to prevent the attacks from outside eavesdroppers, inner participants and quantum center, two single photon sequences are randomly inserted into Bell states: the first sequence is used to perform the quantum channel detection, while the second is applied to disorder the positions of message qubits, which guarantees the security of the protocol.

A perturbation method to the tent map based on Lyapunov exponent and its application

NASA Astrophysics Data System (ADS)

Cao, Lv-Chen; Luo, Yu-Ling; Qiu, Sen-Hui; Liu, Jun-Xiu

2015-10-01

Perturbation imposed on a chaos system is an effective way to maintain its chaotic features. A novel parameter perturbation method for the tent map based on the Lyapunov exponent is proposed in this paper. The pseudo-random sequence generated by the tent map is sent to another chaos function — the Chebyshev map for the post processing. If the output value of the Chebyshev map falls into a certain range, it will be sent back to replace the parameter of the tent map. As a result, the parameter of the tent map keeps changing dynamically. The statistical analysis and experimental results prove that the disturbed tent map has a highly random distribution and achieves good cryptographic properties of a pseudo-random sequence. As a result, it weakens the phenomenon of strong correlation caused by the finite precision and effectively compensates for the digital chaos system dynamics degradation. Project supported by the Guangxi Provincial Natural Science Foundation, China (Grant No. 2014GXNSFBA118271), the Research Project of Guangxi University, China (Grant No. ZD2014022), the Fund from Guangxi Provincial Key Laboratory of Multi-source Information Mining & Security, China (Grant No. MIMS14-04), the Fund from the Guangxi Provincial Key Laboratory of Wireless Wideband Communication & Signal Processing, China (Grant No. GXKL0614205), the Education Development Foundation and the Doctoral Research Foundation of Guangxi Normal University, the State Scholarship Fund of China Scholarship Council (Grant No. [2014]3012), and the Innovation Project of Guangxi Graduate Education, China (Grant No. YCSZ2015102).

Video encryption using chaotic masks in joint transform correlator

NASA Astrophysics Data System (ADS)

Saini, Nirmala; Sinha, Aloka

2015-03-01

A real-time optical video encryption technique using a chaotic map has been reported. In the proposed technique, each frame of video is encrypted using two different chaotic random phase masks in the joint transform correlator architecture. The different chaotic random phase masks can be obtained either by using different iteration levels or by using different seed values of the chaotic map. The use of different chaotic random phase masks makes the decryption process very complex for an unauthorized person. Optical, as well as digital, methods can be used for video encryption but the decryption is possible only digitally. To further enhance the security of the system, the key parameters of the chaotic map are encoded using RSA (Rivest-Shamir-Adleman) public key encryption. Numerical simulations are carried out to validate the proposed technique.

Being First Matters: Topographical Representational Similarity Analysis of ERP Signals Reveals Separate Networks for Audiovisual Temporal Binding Depending on the Leading Sense.

PubMed

Cecere, Roberto; Gross, Joachim; Willis, Ashleigh; Thut, Gregor

2017-05-24

In multisensory integration, processing in one sensory modality is enhanced by complementary information from other modalities. Intersensory timing is crucial in this process because only inputs reaching the brain within a restricted temporal window are perceptually bound. Previous research in the audiovisual field has investigated various features of the temporal binding window, revealing asymmetries in its size and plasticity depending on the leading input: auditory-visual (AV) or visual-auditory (VA). Here, we tested whether separate neuronal mechanisms underlie this AV-VA dichotomy in humans. We recorded high-density EEG while participants performed an audiovisual simultaneity judgment task including various AV-VA asynchronies and unisensory control conditions (visual-only, auditory-only) and tested whether AV and VA processing generate different patterns of brain activity. After isolating the multisensory components of AV-VA event-related potentials (ERPs) from the sum of their unisensory constituents, we ran a time-resolved topographical representational similarity analysis (tRSA) comparing the AV and VA ERP maps. Spatial cross-correlation matrices were built from real data to index the similarity between the AV and VA maps at each time point (500 ms window after stimulus) and then correlated with two alternative similarity model matrices: AV maps = VA maps versus AV maps ≠ VA maps The tRSA results favored the AV maps ≠ VA maps model across all time points, suggesting that audiovisual temporal binding (indexed by synchrony perception) engages different neural pathways depending on the leading sense. The existence of such dual route supports recent theoretical accounts proposing that multiple binding mechanisms are implemented in the brain to accommodate different information parsing strategies in auditory and visual sensory systems. SIGNIFICANCE STATEMENT Intersensory timing is a crucial aspect of multisensory integration, determining whether and how inputs in one modality enhance stimulus processing in another modality. Our research demonstrates that evaluating synchrony of auditory-leading (AV) versus visual-leading (VA) audiovisual stimulus pairs is characterized by two distinct patterns of brain activity. This suggests that audiovisual integration is not a unitary process and that different binding mechanisms are recruited in the brain based on the leading sense. These mechanisms may be relevant for supporting different classes of multisensory operations, for example, auditory enhancement of visual attention (AV) and visual enhancement of auditory speech (VA). Copyright © 2017 Cecere et al.

Color image encryption based on gyrator transform and Arnold transform

NASA Astrophysics Data System (ADS)

Sui, Liansheng; Gao, Bo

2013-06-01

A color image encryption scheme using gyrator transform and Arnold transform is proposed, which has two security levels. In the first level, the color image is separated into three components: red, green and blue, which are normalized and scrambled using the Arnold transform. The green component is combined with the first random phase mask and transformed to an interim using the gyrator transform. The first random phase mask is generated with the sum of the blue component and a logistic map. Similarly, the red component is combined with the second random phase mask and transformed to three-channel-related data. The second random phase mask is generated with the sum of the phase of the interim and an asymmetrical tent map. In the second level, the three-channel-related data are scrambled again and combined with the third random phase mask generated with the sum of the previous chaotic maps, and then encrypted into a gray scale ciphertext. The encryption result has stationary white noise distribution and camouflage property to some extent. In the process of encryption and decryption, the rotation angle of gyrator transform, the iterative numbers of Arnold transform, the parameters of the chaotic map and generated accompanied phase function serve as encryption keys, and hence enhance the security of the system. Simulation results and security analysis are presented to confirm the security, validity and feasibility of the proposed scheme.

Implementing controlled-unitary operations over the butterfly network

NASA Astrophysics Data System (ADS)

Soeda, Akihito; Kinjo, Yoshiyuki; Turner, Peter S.; Murao, Mio

2014-12-01

We introduce a multiparty quantum computation task over a network in a situation where the capacities of both the quantum and classical communication channels of the network are limited and a bottleneck occurs. Using a resource setting introduced by Hayashi [1], we present an efficient protocol for performing controlled-unitary operations between two input nodes and two output nodes over the butterfly network, one of the most fundamental networks exhibiting the bottleneck problem. This result opens the possibility of developing a theory of quantum network coding for multiparty quantum computation, whereas the conventional network coding only treats multiparty quantum communication.

The pressure and entropy of a unitary Fermi gas with particle-hole fluctuation

NASA Astrophysics Data System (ADS)

Gong, Hao; Ruan, Xiao-Xia; Zong, Hong-Shi

2018-01-01

We calculate the pressure and entropy of a unitary Fermi gas based on universal relations combined with our previous prediction of energy which was calculated within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. The resulting entropy and pressure are compared with the experimental data and the theoretical results without induced interaction. For entropy, we find good agreement between our results with particle-hole fluctuation and the experimental measurements reported by ENS group and MIT experiment. For pressure, our results suffer from a systematic upshift compared to MIT data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krebs, H., E-mail: hermann.krebs@rub.de; Epelbaum, E., E-mail: evgeny.epelbaum@rub.de; Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93016

We present the complete derivation of the nuclear axial charge and current operators as well as the pseudoscalar operators to fourth order in the chiral expansion relative to the dominant one-body contribution using the method of unitary transformation. We demonstrate that the unitary ambiguity in the resulting operators can be eliminated by the requirement of renormalizability and by matching of the pion-pole contributions to the nuclear forces. We give expressions for the renormalized single-, two- and three-nucleon contributions to the charge and current operators and pseudoscalar operators including the relevant relativistic corrections. We also verify explicitly the validity of themore » continuity equation.« less

FAST TRACK COMMUNICATION Quantum entanglement: the unitary 8-vertex braid matrix with imaginary rapidity

NASA Astrophysics Data System (ADS)

Chakrabarti, Amitabha; Chakraborti, Anirban; Jedidi, Aymen

2010-12-01

We study quantum entanglements induced on product states by the action of 8-vertex braid matrices, rendered unitary with purely imaginary spectral parameters (rapidity). The unitarity is displayed via the 'canonical factorization' of the coefficients of the projectors spanning the basis. This adds one more new facet to the famous and fascinating features of the 8-vertex model. The double periodicity and the analytic properties of the elliptic functions involved lead to a rich structure of the 3-tangle quantifying the entanglement. We thus explore the complex relationship between topological and quantum entanglement.

A unitary convolution approximation for the impact-parameter dependent electronic energy loss

NASA Astrophysics Data System (ADS)

Schiwietz, G.; Grande, P. L.

1999-06-01

In this work, we propose a simple method to calculate the impact-parameter dependence of the electronic energy loss of bare ions for all impact parameters. This perturbative convolution approximation (PCA) is based on first-order perturbation theory, and thus, it is only valid for fast particles with low projectile charges. Using Bloch's stopping-power result and a simple scaling, we get rid of the restriction to low charge states and derive the unitary convolution approximation (UCA). Results of the UCA are then compared with full quantum-mechanical coupled-channel calculations for the impact-parameter dependent electronic energy loss.

Implementing controlled-unitary operations over the butterfly network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soeda, Akihito; Kinjo, Yoshiyuki; Turner, Peter S.

2014-12-04

We introduce a multiparty quantum computation task over a network in a situation where the capacities of both the quantum and classical communication channels of the network are limited and a bottleneck occurs. Using a resource setting introduced by Hayashi [1], we present an efficient protocol for performing controlled-unitary operations between two input nodes and two output nodes over the butterfly network, one of the most fundamental networks exhibiting the bottleneck problem. This result opens the possibility of developing a theory of quantum network coding for multiparty quantum computation, whereas the conventional network coding only treats multiparty quantum communication.

Improving the capacity of the Boström-Felbinger protocol

NASA Astrophysics Data System (ADS)

Cai, Qing-Yu; Li, Bai-Wen

2004-05-01

We show that the capacity of the Boström-Felbinger (ping-pong) protocol [

Extending matchgates into universal quantum computation

NASA Astrophysics Data System (ADS)

Brod, Daniel J.; Galvão, Ernesto F.

2011-08-01

Matchgates are a family of two-qubit gates associated with noninteracting fermions. They are classically simulatable if acting only on nearest neighbors but become universal for quantum computation if we relax this restriction or use swap gates [Jozsa and Miyake, Proc. R. Soc. ANATUAS1364-502110.1098/rspa.2008.0189 464, 3089 (2008)]. We generalize this result by proving that any nonmatchgate parity-preserving unitary is capable of extending the computational power of matchgates into universal quantum computation. We identify the single local invariant of parity-preserving unitaries responsible for this, and discuss related results in the context of fermionic systems.

Geometry of quantum dynamics in infinite-dimensional Hilbert space

NASA Astrophysics Data System (ADS)

Grabowski, Janusz; Kuś, Marek; Marmo, Giuseppe; Shulman, Tatiana

2018-04-01

We develop a geometric approach to quantum mechanics based on the concept of the Tulczyjew triple. Our approach is genuinely infinite-dimensional, i.e. we do not restrict considerations to finite-dimensional Hilbert spaces, contrary to many other works on the geometry of quantum mechanics, and include a Lagrangian formalism in which self-adjoint (Schrödinger) operators are obtained as Lagrangian submanifolds associated with the Lagrangian. As a byproduct we also obtain results concerning coadjoint orbits of the unitary group in infinite dimensions, embedding of pure states in the unitary group, and self-adjoint extensions of symmetric relations.

Configurable unitary transformations and linear logic gates using quantum memories.

PubMed

Campbell, G T; Pinel, O; Hosseini, M; Ralph, T C; Buchler, B C; Lam, P K

2014-08-08

We show that a set of optical memories can act as a configurable linear optical network operating on frequency-multiplexed optical states. Our protocol is applicable to any quantum memories that employ off-resonant Raman transitions to store optical information in atomic spins. In addition to the configurability, the protocol also offers favorable scaling with an increasing number of modes where N memories can be configured to implement arbitrary N-mode unitary operations during storage and readout. We demonstrate the versatility of this protocol by showing an example where cascaded memories are used to implement a conditional cz gate.

Analysis of the performance of the drive system and diffuser of the Langley unitary plan wind tunnel

NASA Technical Reports Server (NTRS)

Hasel, L. E.; Stallings, R. L.

1981-01-01

A broad program was initiated at the Langley Research Center in 1973 to reduce the energy consumption of the laboratory. As a part of this program, the performance characteristics of the Unitary Plan Wind Tunnel were reexamined to determine if potential methods for incresing the operating efficiencies of the tunnel could be formulated. The results of that study are summarized. The performance characteristics of the drive system components and the variable-geometry diffuser system of the tunnel are documented and analyzed. Several potential methods for reducing the energy requirements of the facility are discussed.

Assessing map accuracy in a remotely sensed, ecoregion-scale cover map

USGS Publications Warehouse

Edwards, T.C.; Moisen, Gretchen G.; Cutler, D.R.

1998-01-01

Landscape- and ecoregion-based conservation efforts increasingly use a spatial component to organize data for analysis and interpretation. A challenge particular to remotely sensed cover maps generated from these efforts is how best to assess the accuracy of the cover maps, especially when they can exceed 1000 s/km2 in size. Here we develop and describe a methodological approach for assessing the accuracy of large-area cover maps, using as a test case the 21.9 million ha cover map developed for Utah Gap Analysis. As part of our design process, we first reviewed the effect of intracluster correlation and a simple cost function on the relative efficiency of cluster sample designs to simple random designs. Our design ultimately combined clustered and subsampled field data stratified by ecological modeling unit and accessibility (hereafter a mixed design). We next outline estimation formulas for simple map accuracy measures under our mixed design and report results for eight major cover types and the three ecoregions mapped as part of the Utah Gap Analysis. Overall accuracy of the map was 83.2% (SE=1.4). Within ecoregions, accuracy ranged from 78.9% to 85.0%. Accuracy by cover type varied, ranging from a low of 50.4% for barren to a high of 90.6% for man modified. In addition, we examined gains in efficiency of our mixed design compared with a simple random sample approach. In regard to precision, our mixed design was more precise than a simple random design, given fixed sample costs. We close with a discussion of the logistical constraints facing attempts to assess the accuracy of large-area, remotely sensed cover maps.

Mapping disease at an approximated individual level using aggregate data: a case study of mapping New Hampshire birth defects.

PubMed

Shi, Xun; Miller, Stephanie; Mwenda, Kevin; Onda, Akikazu; Reese, Judy; Onega, Tracy; Gui, Jiang; Karagas, Margret; Demidenko, Eugene; Moeschler, John

2013-09-06

Limited by data availability, most disease maps in the literature are for relatively large and subjectively-defined areal units, which are subject to problems associated with polygon maps. High resolution maps based on objective spatial units are needed to more precisely detect associations between disease and environmental factors. We propose to use a Restricted and Controlled Monte Carlo (RCMC) process to disaggregate polygon-level location data to achieve mapping aggregate data at an approximated individual level. RCMC assigns a random point location to a polygon-level location, in which the randomization is restricted by the polygon and controlled by the background (e.g., population at risk). RCMC allows analytical processes designed for individual data to be applied, and generates high-resolution raster maps. We applied RCMC to the town-level birth defect data for New Hampshire and generated raster maps at the resolution of 100 m. Besides the map of significance of birth defect risk represented by p-value, the output also includes a map of spatial uncertainty and a map of hot spots. RCMC is an effective method to disaggregate aggregate data. An RCMC-based disease mapping maximizes the use of available spatial information, and explicitly estimates the spatial uncertainty resulting from aggregation.

Effective Perron-Frobenius eigenvalue for a correlated random map

NASA Astrophysics Data System (ADS)

Pool, Roman R.; Cáceres, Manuel O.

2010-09-01

We investigate the evolution of random positive linear maps with various type of disorder by analytic perturbation and direct simulation. Our theoretical result indicates that the statistics of a random linear map can be successfully described for long time by the mean-value vector state. The growth rate can be characterized by an effective Perron-Frobenius eigenvalue that strongly depends on the type of correlation between the elements of the projection matrix. We apply this approach to an age-structured population dynamics model. We show that the asymptotic mean-value vector state characterizes the population growth rate when the age-structured model has random vital parameters. In this case our approach reveals the nontrivial dependence of the effective growth rate with cross correlations. The problem was reduced to the calculation of the smallest positive root of a secular polynomial, which can be obtained by perturbations in terms of Green’s function diagrammatic technique built with noncommutative cumulants for arbitrary n -point correlations.

Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) Infection in BALB/c Mice by Feeding Probiotic Lactobacillus acidophilus NP-51

USDA-ARS?s Scientific Manuscript database

The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP). Mice were randomized to ten treatment groups; sentinels, control, heat-killed MAP, viable MAP, heat-killed NP51, viable ...

Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) infection in BALB/c mice by feeding probiotic Lactobacillus acidophilus NP-51

USDA-ARS?s Scientific Manuscript database

The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP). Mice were randomized to ten treatment groups; sentinels, control, heat-killed MAP, viable MAP, heat-killed NP51, viable ...

New machine learning tools for predictive vegetation mapping after climate change: Bagging and Random Forest perform better than Regression Tree Analysis

Treesearch

L.R. Iverson; A.M. Prasad; A. Liaw

2004-01-01

More and better machine learning tools are becoming available for landscape ecologists to aid in understanding species-environment relationships and to map probable species occurrence now and potentially into the future. To thal end, we evaluated three statistical models: Regression Tree Analybib (RTA), Bagging Trees (BT) and Random Forest (RF) for their utility in...

Unified Application of Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields

NASA Technical Reports Server (NTRS)

Erickson, Gary E.

2010-01-01

Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack. The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

Unified Application Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields

NASA Technical Reports Server (NTRS)

Erickson, Gary E.

2008-01-01

Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack (alpha). The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

Circuit-specific intracortical hyperconnectivity in mice with deletion of the autism-associated Met receptor tyrosine kinase

PubMed Central

Qiu, Shenfeng; Anderson, Charles T.; Levitt, Pat; Shepherd, Gordon M. G.

2011-01-01

Local hyperconnectivity in the neocortex is a hypothesized pathophysiological state in autism spectrum disorder (ASD). MET, a receptor tyrosine kinase that regulates dendrite and spine morphogenesis, has been established as a risk gene for ASD. Here, we analyzed the synaptic circuit organization of identified pyramidal neurons in the anterior frontal cortex of mice with a dorsal pallium derived, conditional knockout (cKO) of Met. Synaptic mapping by glutamate uncaging identified layer 2/3 as the main source of local excitatory input to layer 5 projection neurons in controls. In both cKO and heterozygotes this pathway was stronger by a factor of ~2. This increase was both sub-layer and projection-class specific, restricted to corticostriatal neurons in upper layer 5B, and not neighboring corticopontine neurons. Paired recordings in cKO slices demonstrated increased unitary connectivity. We propose that excitatory hyperconnectivity in specific neocortical microcircuits constitutes a physiological basis for Met-mediated ASD risk. PMID:21490227

Test-state approach to the quantum search problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sehrawat, Arun; Nguyen, Le Huy; Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117597

2011-05-15

The search for 'a quantum needle in a quantum haystack' is a metaphor for the problem of finding out which one of a permissible set of unitary mappings - the oracles - is implemented by a given black box. Grover's algorithm solves this problem with quadratic speedup as compared with the analogous search for 'a classical needle in a classical haystack'. Since the outcome of Grover's algorithm is probabilistic - it gives the correct answer with high probability, not with certainty - the answer requires verification. For this purpose we introduce specific test states, one for each oracle. These testmore » states can also be used to realize 'a classical search for the quantum needle' which is deterministic - it always gives a definite answer after a finite number of steps - and 3.41 times as fast as the purely classical search. Since the test-state search and Grover's algorithm look for the same quantum needle, the average number of oracle queries of the test-state search is the classical benchmark for Grover's algorithm.« less

The inhibitory microcircuit of the substantia nigra provides feedback gain control of the basal ganglia output

PubMed Central

Brown, Jennifer; Pan, Wei-Xing; Dudman, Joshua Tate

2014-01-01

Dysfunction of the basal ganglia produces severe deficits in the timing, initiation, and vigor of movement. These diverse impairments suggest a control system gone awry. In engineered systems, feedback is critical for control. By contrast, models of the basal ganglia highlight feedforward circuitry and ignore intrinsic feedback circuits. In this study, we show that feedback via axon collaterals of substantia nigra projection neurons control the gain of the basal ganglia output. Through a combination of physiology, optogenetics, anatomy, and circuit mapping, we elaborate a general circuit mechanism for gain control in a microcircuit lacking interneurons. Our data suggest that diverse tonic firing rates, weak unitary connections and a spatially diffuse collateral circuit with distinct topography and kinetics from feedforward input is sufficient to implement divisive feedback inhibition. The importance of feedback for engineered systems implies that the intranigral microcircuit, despite its absence from canonical models, could be essential to basal ganglia function. DOI: http://dx.doi.org/10.7554/eLife.02397.001 PMID:24849626

Circuit-specific intracortical hyperconnectivity in mice with deletion of the autism-associated Met receptor tyrosine kinase.

PubMed

Qiu, Shenfeng; Anderson, Charles T; Levitt, Pat; Shepherd, Gordon M G

2011-04-13

Local hyperconnectivity in the neocortex is a hypothesized pathophysiological state in autism spectrum disorder (ASD). MET, a receptor tyrosine kinase that regulates dendrite and spine morphogenesis, has been established as a risk gene for ASD. Here, we analyzed the synaptic circuit organization of identified pyramidal neurons in the anterior frontal cortex of mice with a dorsal pallium-derived, conditional knock-out (cKO) of Met. Synaptic mapping by glutamate uncaging identified layer 2/3 as the main source of local excitatory input to layer 5 projection neurons in controls. In both cKO and heterozygotes, this pathway was stronger by a factor of approximately 2. This increase was both sublayer and projection-class specific, restricted to corticostriatal neurons in upper layer 5B and not neighboring corticopontine neurons. Paired recordings in cKO slices demonstrated increased unitary connectivity. We propose that excitatory hyperconnectivity in specific neocortical microcircuits constitutes a physiological basis for Met-mediated ASD risk.

Randomly picked cosmid clones overlap the pyrB and oriC gap in the physical map of the E. coli chromosome.

PubMed Central

Knott, V; Rees, D J; Cheng, Z; Brownlee, G G

1988-01-01

Sets of overlapping cosmid clones generated by random sampling and fingerprinting methods complement data at pyrB (96.5') and oriC (84') in the published physical map of E. coli. A new cloning strategy using sheared DNA, and a low copy, inducible cosmid vector were used in order to reduce bias in libraries, in conjunction with micro-methods for preparing cosmid DNA from a large number of clones. Our results are relevant to the design of the best approach to the physical mapping of large genomes. PMID:2834694

Automated mapping of the ocean floor using the theory of intrinsic random functions of order k

USGS Publications Warehouse

David, M.; Crozel, D.; Robb, James M.

1986-01-01

High-quality contour maps can be computer drawn from single track echo-sounding data by combining Universal Kriging and the theory of intrinsic random function of order K (IRFK). These methods interpolate values among the closely spaced points that lie along relatively widely spaced lines. The technique provides a variance which can be contoured as a quantitative measure of map precision. The technique can be used to evaluate alternative survey trackline configurations and data collection intervals, and can be applied to other types of oceanographic data. ?? 1986 D. Reidel Publishing Company.

The evaluation of lyophilized polymer matrices for administering recombinant human bone morphogenetic protein-2.

PubMed

Duggirala, S S; Rodgers, J B; DeLuca, P P

1996-07-01

Novel unitary devices, prepared by lyophilization of viscous solutions of sodium carboxymethylcellulose (CMC) and methylcellulose (MC), were evaluated as sustained-release delivery systems for recombinant human bone morphogenetic protein-2 (rhBMP-2). In vitro characterization of the unitary devices, which contained rhBMP-2-loaded poly (d,l lactide-co-glycolide) (PLGA) bioerodible particles (BEPs), was conducted over a 2-month period. Determinations included buffer uptake, mass and molecular weight loss and rhBMP-2 release from the unitary devices. CMC devices imbibed approximately 16 times their weight of buffer, while with MC, equilibrium uptake was approximately 6 times the dry weight of the devices. Overall mass loss percentages were approximately 55 and 35%, respectively, for CMC and MC devices. rhBMP-2 release from the devices was essentially a triphasic process: an initial phase during which "free" protein (rhBMP-2 present on the surface and within the pores of the PLGA BEPs) was released, a lag period during which no release was discerned, and then release of "bound" rhBMP-2 (protein adsorbed to the BEPs). The release of bound protein correlated with the mass loss of the polymer which began after 3 weeks. Release from the unitary devices was lower than that from the BEPs alone, due to a retardation effect of the gelled CMC/MC polymers. In rabbits in which full-thickness cranial bone defects were created, the implants were well tolerated and induced significant new bone growth during an 8-week evaluation period. The CMC devices appear to have induced bone earlier (at 2 weeks), but this did not affect eventual 8-week results. CMC devices without rhBMP-2 appeared to provide some bone conduction, in contrast to the blank MC devices.

Encoding Sequential Information in Semantic Space Models: Comparing Holographic Reduced Representation and Random Permutation

PubMed Central

Recchia, Gabriel; Sahlgren, Magnus; Kanerva, Pentti; Jones, Michael N.

2015-01-01

Circular convolution and random permutation have each been proposed as neurally plausible binding operators capable of encoding sequential information in semantic memory. We perform several controlled comparisons of circular convolution and random permutation as means of encoding paired associates as well as encoding sequential information. Random permutations outperformed convolution with respect to the number of paired associates that can be reliably stored in a single memory trace. Performance was equal on semantic tasks when using a small corpus, but random permutations were ultimately capable of achieving superior performance due to their higher scalability to large corpora. Finally, “noisy” permutations in which units are mapped to other units arbitrarily (no one-to-one mapping) perform nearly as well as true permutations. These findings increase the neurological plausibility of random permutations and highlight their utility in vector space models of semantics. PMID:25954306

Optimizing a Sensor Network with Data from Hazard Mapping Demonstrated in a Heavy-Vehicle Manufacturing Facility.

PubMed

Berman, Jesse D; Peters, Thomas M; Koehler, Kirsten A

2018-05-28

To design a method that uses preliminary hazard mapping data to optimize the number and location of sensors within a network for a long-term assessment of occupational concentrations, while preserving temporal variability, accuracy, and precision of predicted hazards. Particle number concentrations (PNCs) and respirable mass concentrations (RMCs) were measured with direct-reading instruments in a large heavy-vehicle manufacturing facility at 80-82 locations during 7 mapping events, stratified by day and season. Using kriged hazard mapping, a statistical approach identified optimal orders for removing locations to capture temporal variability and high prediction precision of PNC and RMC concentrations. We compared optimal-removal, random-removal, and least-optimal-removal orders to bound prediction performance. The temporal variability of PNC was found to be higher than RMC with low correlation between the two particulate metrics (ρ = 0.30). Optimal-removal orders resulted in more accurate PNC kriged estimates (root mean square error [RMSE] = 49.2) at sample locations compared with random-removal order (RMSE = 55.7). For estimates at locations having concentrations in the upper 10th percentile, the optimal-removal order preserved average estimated concentrations better than random- or least-optimal-removal orders (P < 0.01). However, estimated average concentrations using an optimal-removal were not statistically different than random-removal when averaged over the entire facility. No statistical difference was observed for optimal- and random-removal methods for RMCs that were less variable in time and space than PNCs. Optimized removal performed better than random-removal in preserving high temporal variability and accuracy of hazard map for PNC, but not for the more spatially homogeneous RMC. These results can be used to reduce the number of locations used in a network of static sensors for long-term monitoring of hazards in the workplace, without sacrificing prediction performance.

New constraints on modelling the random magnetic field of the MW

NASA Astrophysics Data System (ADS)

Beck, Marcus C.; Beck, Alexander M.; Beck, Rainer; Dolag, Klaus; Strong, Andrew W.; Nielaba, Peter

2016-05-01

We extend the description of the isotropic and anisotropic random component of the small-scale magnetic field within the existing magnetic field model of the Milky Way from Jansson & Farrar, by including random realizations of the small-scale component. Using a magnetic-field power spectrum with Gaussian random fields, the NE2001 model for the thermal electrons and the Galactic cosmic-ray electron distribution from the current GALPROP model we derive full-sky maps for the total and polarized synchrotron intensity as well as the Faraday rotation-measure distribution. While previous work assumed that small-scale fluctuations average out along the line-of-sight or which only computed ensemble averages of random fields, we show that these fluctuations need to be carefully taken into account. Comparing with observational data we obtain not only good agreement with 408 MHz total and WMAP7 22 GHz polarized intensity emission maps, but also an improved agreement with Galactic foreground rotation-measure maps and power spectra, whose amplitude and shape strongly depend on the parameters of the random field. We demonstrate that a correlation length of 0≈22 pc (05 pc being a 5σ lower limit) is needed to match the slope of the observed power spectrum of Galactic foreground rotation-measure maps. Using multiple realizations allows us also to infer errors on individual observables. We find that previously-used amplitudes for random and anisotropic random magnetic field components need to be rescaled by factors of ≈0.3 and 0.6 to account for the new small-scale contributions. Our model predicts a rotation measure of -2.8±7.1 rad/m2 and 04.4±11. rad/m2 for the north and south Galactic poles respectively, in good agreement with observations. Applying our model to deflections of ultra-high-energy cosmic rays we infer a mean deflection of ≈3.5±1.1 degree for 60 EeV protons arriving from CenA.

QuickMap: a public tool for large-scale gene therapy vector insertion site mapping and analysis.

PubMed

Appelt, J-U; Giordano, F A; Ecker, M; Roeder, I; Grund, N; Hotz-Wagenblatt, A; Opelz, G; Zeller, W J; Allgayer, H; Fruehauf, S; Laufs, S

2009-07-01

Several events of insertional mutagenesis in pre-clinical and clinical gene therapy studies have created intense interest in assessing the genomic insertion profiles of gene therapy vectors. For the construction of such profiles, vector-flanking sequences detected by inverse PCR, linear amplification-mediated-PCR or ligation-mediated-PCR need to be mapped to the host cell's genome and compared to a reference set. Although remarkable progress has been achieved in mapping gene therapy vector insertion sites, public reference sets are lacking, as are the possibilities to quickly detect non-random patterns in experimental data. We developed a tool termed QuickMap, which uniformly maps and analyzes human and murine vector-flanking sequences within seconds (available at www.gtsg.org). Besides information about hits in chromosomes and fragile sites, QuickMap automatically determines insertion frequencies in +/- 250 kb adjacency to genes, cancer genes, pseudogenes, transcription factor and (post-transcriptional) miRNA binding sites, CpG islands and repetitive elements (short interspersed nuclear elements (SINE), long interspersed nuclear elements (LINE), Type II elements and LTR elements). Additionally, all experimental frequencies are compared with the data obtained from a reference set, containing 1 000 000 random integrations ('random set'). Thus, for the first time a tool allowing high-throughput profiling of gene therapy vector insertion sites is available. It provides a basis for large-scale insertion site analyses, which is now urgently needed to discover novel gene therapy vectors with 'safe' insertion profiles.

Accelerated 1 H MRSI using randomly undersampled spiral-based k-space trajectories.

PubMed

Chatnuntawech, Itthi; Gagoski, Borjan; Bilgic, Berkin; Cauley, Stephen F; Setsompop, Kawin; Adalsteinsson, Elfar

2014-07-30

To develop and evaluate the performance of an acquisition and reconstruction method for accelerated MR spectroscopic imaging (MRSI) through undersampling of spiral trajectories. A randomly undersampled spiral acquisition and sensitivity encoding (SENSE) with total variation (TV) regularization, random SENSE+TV, is developed and evaluated on single-slice numerical phantom, in vivo single-slice MRSI, and in vivo three-dimensional (3D)-MRSI at 3 Tesla. Random SENSE+TV was compared with five alternative methods for accelerated MRSI. For the in vivo single-slice MRSI, random SENSE+TV yields up to 2.7 and 2 times reduction in root-mean-square error (RMSE) of reconstructed N-acetyl aspartate (NAA), creatine, and choline maps, compared with the denoised fully sampled and uniformly undersampled SENSE+TV methods with the same acquisition time, respectively. For the in vivo 3D-MRSI, random SENSE+TV yields up to 1.6 times reduction in RMSE, compared with uniform SENSE+TV. Furthermore, by using random SENSE+TV, we have demonstrated on the in vivo single-slice and 3D-MRSI that acceleration factors of 4.5 and 4 are achievable with the same quality as the fully sampled data, as measured by RMSE of reconstructed NAA map, respectively. With the same scan time, random SENSE+TV yields lower RMSEs of metabolite maps than other methods evaluated. Random SENSE+TV achieves up to 4.5-fold acceleration with comparable data quality as the fully sampled acquisition. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

The Effectiveness of Conflict Maps and the V-Shape Teaching Method in Science Conceptual Change among Eighth-Grade Students in Jordan

ERIC Educational Resources Information Center

Bawaneh, Ali Khalid Ali; Zain, Ahmad Nurulazam Md; Ghazali, Munirah

2010-01-01

The purpose of the present study is to investigate the effectiveness of Conflict Maps and the V-Shape method as teaching methods in bringing about conceptual change in science among primary eighth-grade students in Jordan. A randomly selected sample (N = 63) from the Bani Kenana region North of Jordan was randomly assigned to the two teaching…

Recent forest cover changes (2002-2015) in the Southern Carpathians: A case study of the Iezer Mountains, Romania.

PubMed

Mihai, Bogdan; Săvulescu, Ionuț; Rujoiu-Mare, Marina; Nistor, Constantin

2017-12-01

The paper explores the dynamics of the forest cover change in the Iezer Mountains, part of Southern Carpathians, in the context of the forest ownership recovery and deforestation processes, combined with the effects of biotic and abiotic disturbances. The aim of the study is to map and evaluate the typology and the spatial extension of changes in the montane forest cover between 700 and 2462m a.s.l., sampling all the representative Carpathian ecosystems, from the European beech zone up to the spruce-fir zone and the subalpine-alpine pastures. The methodology uses a change detection analysis of satellite imagery with Landsat ETM+/OLI and Sentinel-2 MSI data. The workflow started with a complete calibration of multispectral data from 2002, before the massive forest restitution to private owners, after the Law 247/2005 empowerment, and 2015, the intensification of deforestation process. For the data classification, a Maximum Likelihood supervised classification algorithm was utilized. The forest change map was developed after combining the classifications in a unitary formula using image difference. The principal outcome of the research identifies the type of forest cover change using a quantitative formula. This information can be integrated in the future decision-making strategies for forest stand management and sustainable development. Copyright © 2017 Elsevier B.V. All rights reserved.

What is the optimal way to prepare a Bell state using measurement and feedback?

NASA Astrophysics Data System (ADS)

Martin, Leigh; Sayrafi, Mahrud; Whaley, K. Birgitta

2017-12-01

Recent work has shown that the use of quantum feedback can significantly enhance both the speed and success rate of measurement-based remote entanglement generation, but it is generally unknown what feedback protocols are optimal for these tasks. Here we consider two common measurements that are capable of projecting into pairwise entangled states, namely half- and full-parity measurements of two qubits, and determine in each case a globally optimal protocol for generation of entanglement. For the half-parity measurement, we rederive a previously described protocol using more general methods and prove that it is globally optimal for several figures of merit, including maximal concurrence or fidelity and minimal time to reach a specified concurrence or fidelity. For the full-parity measurement, we derive a protocol for rapid entanglement generation related to that of (Hill, Ralph, Phys. Rev. A 77, 014305), and then map the dynamics of the concurrence of the state to the Bloch vector length of an effective qubit. This mapping allows us to prove several optimality results for feedback protocols with full-parity measurements. We further show that our full-parity protocol transfers entanglement optimally from one qubit to the other amongst all measurement-based schemes. The methods developed here will be useful for deriving feedback protocols and determining their optimality properties in many other quantum systems subject to measurement and unitary operations.

Mapping grey matter reductions in schizophrenia: an anatomical likelihood estimation analysis of voxel-based morphometry studies.

PubMed

Fornito, A; Yücel, M; Patti, J; Wood, S J; Pantelis, C

2009-03-01

Voxel-based morphometry (VBM) is a popular tool for mapping neuroanatomical changes in schizophrenia patients. Several recent meta-analyses have identified the brain regions in which patients most consistently show grey matter reductions, although they have not examined whether such changes reflect differences in grey matter concentration (GMC) or grey matter volume (GMV). These measures assess different aspects of grey matter integrity, and may therefore reflect different pathological processes. In this study, we used the Anatomical Likelihood Estimation procedure to analyse significant differences reported in 37 VBM studies of schizophrenia patients, incorporating data from 1646 patients and 1690 controls, and compared the findings of studies using either GMC or GMV to index grey matter differences. Analysis of all studies combined indicated that grey matter reductions in a network of frontal, temporal, thalamic and striatal regions are among the most frequently reported in literature. GMC reductions were generally larger and more consistent than GMV reductions, and were more frequent in the insula, medial prefrontal, medial temporal and striatal regions. GMV reductions were more frequent in dorso-medial frontal cortex, and lateral and orbital frontal areas. These findings support the primacy of frontal, limbic, and subcortical dysfunction in the pathophysiology of schizophrenia, and suggest that the grey matter changes observed with MRI may not necessarily result from a unitary pathological process.

Construction of optimal resources for concatenated quantum protocols

NASA Astrophysics Data System (ADS)

Pirker, A.; Wallnöfer, J.; Briegel, H. J.; Dür, W.

2017-06-01

We consider the explicit construction of resource states for measurement-based quantum information processing. We concentrate on special-purpose resource states that are capable to perform a certain operation or task, where we consider unitary Clifford circuits as well as non-trace-preserving completely positive maps, more specifically probabilistic operations including Clifford operations and Pauli measurements. We concentrate on 1 →m and m →1 operations, i.e., operations that map one input qubit to m output qubits or vice versa. Examples of such operations include encoding and decoding in quantum error correction, entanglement purification, or entanglement swapping. We provide a general framework to construct optimal resource states for complex tasks that are combinations of these elementary building blocks. All resource states only contain input and output qubits, and are hence of minimal size. We obtain a stabilizer description of the resulting resource states, which we also translate into a circuit pattern to experimentally generate these states. In particular, we derive recurrence relations at the level of stabilizers as key analytical tool to generate explicit (graph) descriptions of families of resource states. This allows us to explicitly construct resource states for encoding, decoding, and syndrome readout for concatenated quantum error correction codes, code switchers, multiple rounds of entanglement purification, quantum repeaters, and combinations thereof (such as resource states for entanglement purification of encoded states).

A Numerical Study of New Logistic Map

NASA Astrophysics Data System (ADS)

Khmou, Youssef

In this paper, we propose a new logistic map based on the relation of the information entropy, we study the bifurcation diagram comparatively to the standard logistic map. In the first part, we compare the obtained diagram, by numerical simulations, with that of the standard logistic map. It is found that the structures of both diagrams are similar where the range of the growth parameter is restricted to the interval [0,e]. In the second part, we present an application of the proposed map in traffic flow using macroscopic model. It is found that the bifurcation diagram is an exact model of the Greenberg’s model of traffic flow where the growth parameter corresponds to the optimal velocity and the random sequence corresponds to the density. In the last part, we present a second possible application of the proposed map which consists of random number generation. The results of the analysis show that the excluded initial values of the sequences are (0,1).

A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.

PubMed

Mascaro, Joseph; Asner, Gregory P; Knapp, David E; Kennedy-Bowdoin, Ty; Martin, Roberta E; Anderson, Christopher; Higgins, Mark; Chadwick, K Dana

2014-01-01

Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including--in the latter case--x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called "out-of-bag"), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha(-1) when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation.

A Tale of Two “Forests”: Random Forest Machine Learning Aids Tropical Forest Carbon Mapping

PubMed Central

Mascaro, Joseph; Asner, Gregory P.; Knapp, David E.; Kennedy-Bowdoin, Ty; Martin, Roberta E.; Anderson, Christopher; Higgins, Mark; Chadwick, K. Dana

2014-01-01

Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including—in the latter case—x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called “out-of-bag”), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha−1 when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation. PMID:24489686

Model Deformation and Optical Angle of Attack Measurement System in the NASA Ames Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Kushner, Laura K.; Drain, Bethany A.; Schairer, Edward T.; Heineck, James T.; Bell, James H.

2017-01-01

Both AoA and MDM measurements can be made using an optical system that relies on photogrammetry. Optical measurements are being requested by customers in wind tunnels with increasing frequency due to their non-intrusive nature and recent hardware and software advances that allow measurements to become near real time. The NASA Ames Research Center Unitary Plan Wind Tunnel is currently developing a system based on photogrammetry to measure model deformation and model angle of attack. This paper describes the new system, its development, its use on recent tests and plans to further develop the system.

Results of a jet plume effects test on Rockwell International integrated space shuttle vehicle using a vehicle 5 configuration 0.02-scale model (88-OTS) in the 11 by 11 foot leg of the NASA/Ames Research Center unitary plan wind tunnel (IA19), volume 1

NASA Technical Reports Server (NTRS)

Nichols, M. E.

1975-01-01

Results are presented of jet plume effects test IA19 using a vehicle 5 configuration integrated space shuttle vehicle 0.02-scale model in the NASA/Ames Research Center 11 x 11-foot leg of the unitary plan wind tunnel. The jet plume power effects on the integrated vehicle static pressure distribution were determined along with elevon, main propulsion system nozzle, and solid rocket booster nozzle effectiveness and elevon hinge moments.

Robust Assignment Of Eigensystems For Flexible Structures

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Lim, Kyong B.; Junkins, John L.

1992-01-01

Improved method for placement of eigenvalues and eigenvectors of closed-loop control system by use of either state or output feedback. Applied to reduced-order finite-element mathematical model of NASA's MAST truss beam structure. Model represents deployer/retractor assembly, inertial properties of Space Shuttle, and rigid platforms for allocation of sensors and actuators. Algorithm formulated in real arithmetic for efficient implementation. Choice of open-loop eigenvector matrix and its closest unitary matrix believed suitable for generating well-conditioned eigensystem with small control gains. Implication of this approach is that element of iterative search for "optimal" unitary matrix appears unnecessary in practice for many test problems.

Langley Research Center's Unitary Plan Wind Tunnel: Testing Capabilities and Recent Modernization Activities

NASA Technical Reports Server (NTRS)

Micol, John R.

2001-01-01

Description, capabilities, initiatives, and utilization of the NASA Langley Research Center's Unitary Plan Wind Tunnel are presented. A brief overview of the facility's operational capabilities and testing techniques is provided. A recent Construction of Facilities (CoF) project to improve facility productivity and efficiency through facility automation has been completed and is discussed. Several new and maturing thrusts are underway that include systematic efforts to provide credible assessment for data quality, modifications to the new automation control system for increased compatibility with the Modern Design Of Experiments (MDOE) testing methodology, and process improvements for better test coordination, planning, and execution.

Langley Research Center's Unitary Plan Wind Tunnel: Testing Capabilities and Recent Modernization Activities

NASA Technical Reports Server (NTRS)

Micol, John R.

2001-01-01

Description, capabilities, initiatives, and utilization of the NASA Langley Research Center's Unitary Plan Wind Tunnel are presented. A brief overview of the facility's operational capabilities and testing techniques is provided. A recent Construction of Facilities (Car) project to improve facility productivity and efficiency through facility automation has been completed and is discussed. Several new and maturing thrusts are underway that include systematic efforts to provide credible assessment for data quality, modifications to the new automation control system for increased compatibility with the Modern Design of Experiments (MDOE) testing methodology, and process improvements for better test coordination, planning, and execution.

Feasibility study of transit photon correlation anemometer for Ames Research Center unitary wind tunnel plan

NASA Technical Reports Server (NTRS)

Mayo, W. T., Jr.; Smart, A. E.

1979-01-01

A laser transit anemometer measured a two-dimensional vector velocity, using the transit time of scattering particles between two focused and parallel laser beams. The objectives were: (1) the determination of the concentration levels and light scattering efficiencies of naturally occurring, submicron particles in the NASA/Ames unitary wind tunnel and (2) the evaluation based on these measured data of a laser transit anemometer with digital correlation processing for nonintrusive velocity measurement in this facility. The evaluation criteria were the speeds at which point velocity measurements could be realized with this technique (as determined from computer simulations) for given accuracy requirements.

Results of a Pressure Loads Investigation on a 0.030-scale Model (47-OTS) of the Integrated Space Shuttle Vehicle Configuration 5 in the NASA Ames Research Center 11 by 11 Foot Leg of the Unitary Plan Wind Tunnel (IA81A), Volume 1

NASA Technical Reports Server (NTRS)

Chee, E.

1975-01-01

Results of wind tunnel tests on a 0.030-scale model of the integrated space shuttle vehicle configuration 5 are presented. Testing was conducted in the NASA Ames Research Center 11 x 11 foot leg of the Unitary Plan Wind Tunnel to investigate pressure distributions for airloads analyses at Mach numbers from 0.9 through 1.4. Angles of attack and sideslip were varied from -6 to +6 degrees.

N = 2 supersymmetry and Bailey pairs

NASA Astrophysics Data System (ADS)

Berkovich, Alexander; McCoy, Barry M.; Schilling, Anne

1996-02-01

We demonstrate that the Bailey pair formulation of Rogers-Ramanujan identities unifies the calculations of the characters of N = 1 and N = 2 supersymmetric conformal field theories with the counterpart theory with no supersymmetry. We illustrate this construction for the M(3,4) (Ising) model where the Bailey pairs have been given by Slater. We then present the general unitary case. We demonstrate that the model M( p,p + 1) is derived from M( p - 1, p) by a Bailey renormalization flow and conclude by obtaining the N = 1 model SM( p,p + 2) and the unitary N = 2 model with central charge c = 3(1 - 2/ p).

Strong Unitary and Overlap Uncertainty Relations: Theory and Experiment

NASA Astrophysics Data System (ADS)

Bong, Kok-Wei; Tischler, Nora; Patel, Raj B.; Wollmann, Sabine; Pryde, Geoff J.; Hall, Michael J. W.

2018-06-01

We derive and experimentally investigate a strong uncertainty relation valid for any n unitary operators, which implies the standard uncertainty relation and others as special cases, and which can be written in terms of geometric phases. It is saturated by every pure state of any n -dimensional quantum system, generates a tight overlap uncertainty relation for the transition probabilities of any n +1 pure states, and gives an upper bound for the out-of-time-order correlation function. We test these uncertainty relations experimentally for photonic polarization qubits, including the minimum uncertainty states of the overlap uncertainty relation, via interferometric measurements of generalized geometric phases.

A nursing theory-guided framework for genetic and epigenetic research.

PubMed

Maki, Katherine A; DeVon, Holli A

2018-04-01

The notion that genetics, through natural selection, determines innate traits has led to much debate and divergence of thought on the impact of innate traits on the human phenotype. The purpose of this synthesis was to examine how innate theory informs genetic research and how understanding innate theory through the lens of Martha Rogers' theory of unitary human beings can offer a contemporary view of how innate traits can inform epigenetic and genetic research. We also propose a new conceptual model for genetic and epigenetic research. The philosophical, theoretical, and research literatures were examined for this synthesis. We have merged philosophical and conceptual phenomena from innate theory with the theory of unitary beings into the University of Illinois at Chicago model for genetic and epigenetic research. Innate traits are the cornerstone of the framework but may be modified epigenetically by biological, physiological, psychological, and social determinants as they are transcribed. These modifiers serve as important links between the concept of innate traits and epigenetic modifications, and, like the theory of unitary human beings, the process is understood in the context of individual and environmental interaction that has the potential to evolve as the determinants change. © 2018 John Wiley & Sons Ltd.

Probing CP violation with non-unitary mixing in long-baseline neutrino oscillation experiments: DUNE as a case study

DOE PAGES

Escrihuela, F. J.; Forero, D. V.; Miranda, O. G.; ...

2017-09-08

When neutrino masses arise from the exchange of neutral heavy leptons, as in most seesaw schemes, the effective lepton mixing matrix N describing neutrino propagation is non-unitary, hence neutrinos are not exactly orthonormal. New CP violation phases appear in N that could be confused with the standard phasemore » $${\\delta }_{\\mathrm{CP}}$$ characterizing the three neutrino paradigm.We study the potential of the long-baseline neutrino experiment DUNE in probing CP violation induced by the standard CP phase in the presence of non-unitarity. In order to accomplish this we develop our previous formalism, so as to take into account the neutrino interactions with the medium, important in long baseline experiments such as DUNE. In this study we find that the expected CP sensitivity of DUNE is somewhat degraded with respect to that characterizing the standard unitary case. However the effect is weaker than might have been expected thanks mainly to the wide neutrino beam. We also investigate the sensitivity of DUNE to the parameters characterizing non-unitarity. In this case we find that there is no improvement expected with respect to the current situation, unless the near detector setup is revamped.« less

Unique Fock quantization of a massive fermion field in a cosmological scenario

NASA Astrophysics Data System (ADS)

Cortez, Jerónimo; Elizaga Navascués, Beatriz; Martín-Benito, Mercedes; Mena Marugán, Guillermo A.; Velhinho, José M.

2016-04-01

It is well known that the Fock quantization of field theories in general spacetimes suffers from an infinite ambiguity, owing to the inequivalent possibilities in the selection of a representation of the canonical commutation or anticommutation relations, but also owing to the freedom in the choice of variables to describe the field among all those related by linear time-dependent transformations, including the dependence through functions of the background. In this work we remove this ambiguity (up to unitary equivalence) in the case of a massive Dirac free field propagating in a spacetime with homogeneous and isotropic spatial sections of spherical topology. Two physically reasonable conditions are imposed in order to arrive at this result: (a) The invariance of the vacuum under the spatial isometries of the background, and (b) the unitary implementability of the dynamical evolution that dictates the Dirac equation. We characterize the Fock quantizations with a nontrivial fermion dynamics that satisfy these two conditions. Then, we provide a complete proof of the unitary equivalence of the representations in this class under very mild requirements on the time variation of the background, once a criterion to discern between particles and antiparticles has been set.

Characterization of separability and entanglement in (2xD)- and (3xD)-dimensional systems by single-qubit and single-qutrit unitary transformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giampaolo, Salvatore M.; CNR-INFM Coherentia, Naples; CNISM Unita di Salerno and INFN Sezione di Napoli, Gruppo collegato di Salerno, Baronissi

2007-10-15

We investigate the geometric characterization of pure state bipartite entanglement of (2xD)- and (3xD)-dimensional composite quantum systems. To this aim, we analyze the relationship between states and their images under the action of particular classes of local unitary operations. We find that invariance of states under the action of single-qubit and single-qutrit transformations is a necessary and sufficient condition for separability. We demonstrate that in the (2xD)-dimensional case the von Neumann entropy of entanglement is a monotonic function of the minimum squared Euclidean distance between states and their images over the set of single qubit unitary transformations. Moreover, both inmore » the (2xD)- and in the (3xD)-dimensional cases the minimum squared Euclidean distance exactly coincides with the linear entropy [and thus as well with the tangle measure of entanglement in the (2xD)-dimensional case]. These results provide a geometric characterization of entanglement measures originally established in informational frameworks. Consequences and applications of the formalism to quantum critical phenomena in spin systems are discussed.« less

Nonlinear QR code based optical image encryption using spiral phase transform, equal modulus decomposition and singular value decomposition

NASA Astrophysics Data System (ADS)

Kumar, Ravi; Bhaduri, Basanta; Nishchal, Naveen K.

2018-01-01

In this study, we propose a quick response (QR) code based nonlinear optical image encryption technique using spiral phase transform (SPT), equal modulus decomposition (EMD) and singular value decomposition (SVD). First, the primary image is converted into a QR code and then multiplied with a spiral phase mask (SPM). Next, the product is spiral phase transformed with particular spiral phase function, and further, the EMD is performed on the output of SPT, which results into two complex images, Z 1 and Z 2. Among these, Z 1 is further Fresnel propagated with distance d, and Z 2 is reserved as a decryption key. Afterwards, SVD is performed on Fresnel propagated output to get three decomposed matrices i.e. one diagonal matrix and two unitary matrices. The two unitary matrices are modulated with two different SPMs and then, the inverse SVD is performed using the diagonal matrix and modulated unitary matrices to get the final encrypted image. Numerical simulation results confirm the validity and effectiveness of the proposed technique. The proposed technique is robust against noise attack, specific attack, and brutal force attack. Simulation results are presented in support of the proposed idea.

Stochastic local operations and classical communication (SLOCC) and local unitary operations (LU) classifications of n qubits via ranks and singular values of the spin-flipping matrices

NASA Astrophysics Data System (ADS)

Li, Dafa

2018-06-01

We construct ℓ -spin-flipping matrices from the coefficient matrices of pure states of n qubits and show that the ℓ -spin-flipping matrices are congruent and unitary congruent whenever two pure states of n qubits are SLOCC and LU equivalent, respectively. The congruence implies the invariance of ranks of the ℓ -spin-flipping matrices under SLOCC and then permits a reduction of SLOCC classification of n qubits to calculation of ranks of the ℓ -spin-flipping matrices. The unitary congruence implies the invariance of singular values of the ℓ -spin-flipping matrices under LU and then permits a reduction of LU classification of n qubits to calculation of singular values of the ℓ -spin-flipping matrices. Furthermore, we show that the invariance of singular values of the ℓ -spin-flipping matrices Ω 1^{(n)} implies the invariance of the concurrence for even n qubits and the invariance of the n-tangle for odd n qubits. Thus, the concurrence and the n-tangle can be used for LU classification and computing the concurrence and the n-tangle only performs additions and multiplications of coefficients of states.

Probing CP violation with non-unitary mixing in long-baseline neutrino oscillation experiments: DUNE as a case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escrihuela, F. J.; Forero, D. V.; Miranda, O. G.

When neutrino masses arise from the exchange of neutral heavy leptons, as in most seesaw schemes, the effective lepton mixing matrix N describing neutrino propagation is non-unitary, hence neutrinos are not exactly orthonormal. New CP violation phases appear in N that could be confused with the standard phasemore » $${\\delta }_{\\mathrm{CP}}$$ characterizing the three neutrino paradigm.We study the potential of the long-baseline neutrino experiment DUNE in probing CP violation induced by the standard CP phase in the presence of non-unitarity. In order to accomplish this we develop our previous formalism, so as to take into account the neutrino interactions with the medium, important in long baseline experiments such as DUNE. In this study we find that the expected CP sensitivity of DUNE is somewhat degraded with respect to that characterizing the standard unitary case. However the effect is weaker than might have been expected thanks mainly to the wide neutrino beam. We also investigate the sensitivity of DUNE to the parameters characterizing non-unitarity. In this case we find that there is no improvement expected with respect to the current situation, unless the near detector setup is revamped.« less

Regarding the unitary theory of agonist and antagonist action at presynaptic adrenoceptors.

PubMed

Kalsner, S; Abdali, S A

2001-06-01

1. The linkage between potentiation of field stimulation-induced noradrenaline release and blockade of the presynaptic inhibitory effect of exogenous noradrenaline by a presynaptic antagonist was examined in superfused rabbit aorta preparations. 2. Rauwolscine clearly potentiated the release of noradrenaline in response to 100 pulses at 2 Hz but reduced the capacity of noradrenaline to inhibit transmitter release to a questionable extent, and then only when comparisons were made with untreated, rather then to rauwolscine-treated, controls. 3. Aortic preparations exposed for 60 min to rauwolscine followed by superfusion with antagonist-free Krebs for 60 min retained the potentiation of stimulation-induced transmitter release but no antagonism of the noradrenaline-induced inhibition could be detected at either of two noradrenaline concentrations when comparisons were made with rauwolscine treated controls. 4. Comparisons of the inhibitory effect of exogenous noradrenaline (1.8 x 10-6 M) on transmitter efflux in the presence and absence of rauwolscine pretreatment revealed that the antagonist enhanced rather than antagonized the presynaptic inhibition by noradrenaline. 5 It is concluded that the unitary hypothesis that asserts that antagonist enhancement of transmitter release and its blockade of noradrenaline induced inhibition are manifestations of a unitary event are not supportable.

Conditional Bounds on Polarization Transfer

NASA Astrophysics Data System (ADS)

Nielsen, N. C.; Sorensen, O. W.

The implications of constraints on unitary transformations of spin operators with respect to the accessible regions of Liouville space are analyzed. Specifically, the effects of spin-permutation symmetry on the unitary propagators are investigated. The influence of S2 and S3 propagator symmetry on two-dimensional bounds for F z = Σ Ni=1 I iz ↔ G z = Σ Mj=1 S jz polarization transfer in IS and I 2S spin- {1}/{2} systems is examined in detail. One result is that the maximum achievable F z ↔ G z polarization transfer is not reduced by permutation symmetry among the spins. For I 2S spin systems, S3 symmetry in the unitary propagator is shown to significantly reduce the accessible region in the 2D F z-S z Liouville subspace compared to the case restricted by unitarity alone. That result is compared with transformations under symmetric dipolar and scalar J coupling as well as shift and RF interactions. An important practical implication is that the refined spin thermodynamic theory of Levitt, Suter, and Ernst ( J. Chem. Phys.84, 4243, 1986) for cross polarization in solid-state NMR does not predict experimental outcomes incompatible with constraints of unitarity and spin-permutation symmetry.

Nonunitary Lagrangians and Unitary Non-Lagrangian Conformal Field Theories.

PubMed

Buican, Matthew; Laczko, Zoltan

2018-02-23

In various dimensions, we can sometimes compute observables of interacting conformal field theories (CFTs) that are connected to free theories via the renormalization group (RG) flow by computing protected quantities in the free theories. On the other hand, in two dimensions, it is often possible to algebraically construct observables of interacting CFTs using free fields without the need to explicitly construct an underlying RG flow. In this Letter, we begin to extend this idea to higher dimensions by showing that one can compute certain observables of an infinite set of unitary strongly interacting four-dimensional N=2 superconformal field theories (SCFTs) by performing simple calculations involving sets of nonunitary free four-dimensional hypermultiplets. These free fields are distant cousins of the Majorana fermion underlying the two-dimensional Ising model and are not obviously connected to our interacting theories via an RG flow. Rather surprisingly, this construction gives us Lagrangians for particular observables in certain subsectors of many "non-Lagrangian" SCFTs by sacrificing unitarity while preserving the full N=2 superconformal algebra. As a by-product, we find relations between characters in unitary and nonunitary affine Kac-Moody algebras. We conclude by commenting on possible generalizations of our construction.

A Unitary ESPRIT Scheme of Joint Angle Estimation for MOTS MIMO Radar

PubMed Central

Wen, Chao; Shi, Guangming

2014-01-01

The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme. PMID:25106023

Direction of Arrival Estimation for MIMO Radar via Unitary Nuclear Norm Minimization

PubMed Central

Wang, Xianpeng; Huang, Mengxing; Wu, Xiaoqin; Bi, Guoan

2017-01-01

In this paper, we consider the direction of arrival (DOA) estimation issue of noncircular (NC) source in multiple-input multiple-output (MIMO) radar and propose a novel unitary nuclear norm minimization (UNNM) algorithm. In the proposed method, the noncircular properties of signals are used to double the virtual array aperture, and the real-valued data are obtained by utilizing unitary transformation. Then a real-valued block sparse model is established based on a novel over-complete dictionary, and a UNNM algorithm is formulated for recovering the block-sparse matrix. In addition, the real-valued NC-MUSIC spectrum is used to design a weight matrix for reweighting the nuclear norm minimization to achieve the enhanced sparsity of solutions. Finally, the DOA is estimated by searching the non-zero blocks of the recovered matrix. Because of using the noncircular properties of signals to extend the virtual array aperture and an additional real structure to suppress the noise, the proposed method provides better performance compared with the conventional sparse recovery based algorithms. Furthermore, the proposed method can handle the case of underdetermined DOA estimation. Simulation results show the effectiveness and advantages of the proposed method. PMID:28441770

Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, paranoid personality disorder diagnosis: a unitary or a two-dimensional construct?

PubMed

Falkum, Erik; Pedersen, Geir; Karterud, Sigmund

2009-01-01

This article examines reliability and validity aspects of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) paranoid personality disorder (PPD) diagnosis. Patients with personality disorders (n = 930) from the Norwegian network of psychotherapeutic day hospitals, of which 114 had PPD, were included in the study. Frequency distribution, chi(2), correlations, reliability statistics, exploratory, and confirmatory factor analyses were performed. The distribution of PPD criteria revealed no distinct boundary between patients with and without PPD. Diagnostic category membership was obtained in 37 of 64 theoretically possible ways. The PPD criteria formed a separate factor in a principal component analysis, whereas a confirmatory factor analysis indicated that the DSM-IV PPD construct consists of 2 separate dimensions as follows: suspiciousness and hostility. The reliability of the unitary PPD scale was only 0.70, probably partly due to the apparent 2-dimensionality of the construct. Persistent unwarranted doubts about the loyalty of friends had the highest diagnostic efficiency, whereas unwarranted accusations of infidelity of partner had particularly poor indicator properties. The reliability and validity of the unitary PPD construct may be questioned. The 2-dimensional PPD model should be further explored.

A unitary ESPRIT scheme of joint angle estimation for MOTS MIMO radar.

PubMed

Wen, Chao; Shi, Guangming

2014-08-07

The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme.

Nonunitary Lagrangians and Unitary Non-Lagrangian Conformal Field Theories

NASA Astrophysics Data System (ADS)

Buican, Matthew; Laczko, Zoltan

2018-02-01

In various dimensions, we can sometimes compute observables of interacting conformal field theories (CFTs) that are connected to free theories via the renormalization group (RG) flow by computing protected quantities in the free theories. On the other hand, in two dimensions, it is often possible to algebraically construct observables of interacting CFTs using free fields without the need to explicitly construct an underlying RG flow. In this Letter, we begin to extend this idea to higher dimensions by showing that one can compute certain observables of an infinite set of unitary strongly interacting four-dimensional N =2 superconformal field theories (SCFTs) by performing simple calculations involving sets of nonunitary free four-dimensional hypermultiplets. These free fields are distant cousins of the Majorana fermion underlying the two-dimensional Ising model and are not obviously connected to our interacting theories via an RG flow. Rather surprisingly, this construction gives us Lagrangians for particular observables in certain subsectors of many "non-Lagrangian" SCFTs by sacrificing unitarity while preserving the full N =2 superconformal algebra. As a by-product, we find relations between characters in unitary and nonunitary affine Kac-Moody algebras. We conclude by commenting on possible generalizations of our construction.

PyCCF: Python Cross Correlation Function for reverberation mapping studies

NASA Astrophysics Data System (ADS)

Sun, Mouyuan; Grier, C. J.; Peterson, B. M.

2018-05-01

PyCCF emulates a Fortran program written by B. Peterson for use with reverberation mapping. The code cross correlates two light curves that are unevenly sampled using linear interpolation and measures the peak and centroid of the cross-correlation function. In addition, it is possible to run Monto Carlo iterations using flux randomization and random subset selection (RSS) to produce cross-correlation centroid distributions to estimate the uncertainties in the cross correlation results.

A general framework for complete positivity

NASA Astrophysics Data System (ADS)

Dominy, Jason M.; Shabani, Alireza; Lidar, Daniel A.

2016-01-01

Complete positivity of quantum dynamics is often viewed as a litmus test for physicality; yet, it is well known that correlated initial states need not give rise to completely positive evolutions. This observation spurred numerous investigations over the past two decades attempting to identify necessary and sufficient conditions for complete positivity. Here, we describe a complete and consistent mathematical framework for the discussion and analysis of complete positivity for correlated initial states of open quantum systems. This formalism is built upon a few simple axioms and is sufficiently general to contain all prior methodologies going back to Pechakas (Phys Rev Lett 73:1060-1062, 1994). The key observation is that initial system-bath states with the same reduced state on the system must evolve under all admissible unitary operators to system-bath states with the same reduced state on the system, in order to ensure that the induced dynamical maps on the system are well defined. Once this consistency condition is imposed, related concepts such as the assignment map and the dynamical maps are uniquely defined. In general, the dynamical maps may not be applied to arbitrary system states, but only to those in an appropriately defined physical domain. We show that the constrained nature of the problem gives rise to not one but three inequivalent types of complete positivity. Using this framework, we elucidate the limitations of recent attempts to provide conditions for complete positivity using quantum discord and the quantum data processing inequality. In particular, we correct the claim made by two of us (Shabani and Lidar in Phys Rev Lett 102:100402-100404, 2009) that vanishing discord is necessary for complete positivity, and explain that it is valid only for a particular class of initial states. The problem remains open, and may require fresh perspectives and new mathematical tools. The formalism presented herein may be one step in that direction.

Brick tunnel randomization and the momentum of the probability mass.

PubMed

Kuznetsova, Olga M

2015-12-30

The allocation space of an unequal-allocation permuted block randomization can be quite wide. The development of unequal-allocation procedures with a narrower allocation space, however, is complicated by the need to preserve the unconditional allocation ratio at every step (the allocation ratio preserving (ARP) property). When the allocation paths are depicted on the K-dimensional unitary grid, where allocation to the l-th treatment is represented by a step along the l-th axis, l = 1 to K, the ARP property can be expressed in terms of the center of the probability mass after i allocations. Specifically, for an ARP allocation procedure that randomizes subjects to K treatment groups in w1 :⋯:wK ratio, w1 +⋯+wK =1, the coordinates of the center of the mass are (w1 i,…,wK i). In this paper, the momentum with respect to the center of the probability mass (expected imbalance in treatment assignments) is used to compare ARP procedures in how closely they approximate the target allocation ratio. It is shown that the two-arm and three-arm brick tunnel randomizations (BTR) are the ARP allocation procedures with the tightest allocation space among all allocation procedures with the same allocation ratio; the two-arm BTR is the minimum-momentum two-arm ARP allocation procedure. Resident probabilities of two-arm and three-arm BTR are analytically derived from the coordinates of the center of the probability mass; the existence of the respective transition probabilities is proven. Probability of deterministic assignments with BTR is found generally acceptable. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Topographic Independent Component Analysis reveals random scrambling of orientation in visual space

PubMed Central

Martinez-Garcia, Marina; Martinez, Luis M.

2017-01-01

Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space. There is an active debate on the origin of these locally continuous maps. While most of the existing descriptions take purely geometric/mechanistic approaches which disregard the network function, a clear exception to this trend in the literature is the original approach of Hyvärinen and Hoyer based on infomax and Topographic Independent Component Analysis (TICA). Although TICA successfully addresses a number of other properties of V1 simple and complex cells, in this work we question the validity of the orientation maps obtained from TICA. We argue that the maps predicted by TICA can be analyzed in the retinal space, and when doing so, it is apparent that they lack the required continuity and retinotopy. Here we show that in the orientation maps reported in the TICA literature it is easy to find examples of violation of the continuity between similarly tuned mechanisms in the retinal space, which suggest a random scrambling incompatible with the maps in primates. The new experiments in the retinal space presented here confirm this guess: TICA basis vectors actually follow a random salt-and-pepper organization back in the image space. Therefore, the interesting clusters found in the TICA topology cannot be interpreted as the actual cortical orientation maps found in cats, primates or humans. In conclusion, Topographic ICA does not reproduce cortical orientation maps. PMID:28640816

Topographic Independent Component Analysis reveals random scrambling of orientation in visual space.

PubMed

Martinez-Garcia, Marina; Martinez, Luis M; Malo, Jesús

2017-01-01

Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space. There is an active debate on the origin of these locally continuous maps. While most of the existing descriptions take purely geometric/mechanistic approaches which disregard the network function, a clear exception to this trend in the literature is the original approach of Hyvärinen and Hoyer based on infomax and Topographic Independent Component Analysis (TICA). Although TICA successfully addresses a number of other properties of V1 simple and complex cells, in this work we question the validity of the orientation maps obtained from TICA. We argue that the maps predicted by TICA can be analyzed in the retinal space, and when doing so, it is apparent that they lack the required continuity and retinotopy. Here we show that in the orientation maps reported in the TICA literature it is easy to find examples of violation of the continuity between similarly tuned mechanisms in the retinal space, which suggest a random scrambling incompatible with the maps in primates. The new experiments in the retinal space presented here confirm this guess: TICA basis vectors actually follow a random salt-and-pepper organization back in the image space. Therefore, the interesting clusters found in the TICA topology cannot be interpreted as the actual cortical orientation maps found in cats, primates or humans. In conclusion, Topographic ICA does not reproduce cortical orientation maps.

Randomly chosen chaotic maps can give rise to nearly ordered behavior

NASA Astrophysics Data System (ADS)

Boyarsky, Abraham; Góra, Paweł; Islam, Md. Shafiqul

2005-10-01

Parrondo’s paradox [J.M.R. Parrondo, G.P. Harmer, D. Abbott, New paradoxical games based on Brownian ratchets, Phys. Rev. Lett. 85 (2000), 5226-5229] (see also [O.E. Percus, J.K. Percus, Can two wrongs make a right? Coin-tossing games and Parrondo’s paradox, Math. Intelligencer 24 (3) (2002) 68-72]) states that two losing gambling games when combined one after the other (either deterministically or randomly) can result in a winning game: that is, a losing game followed by a losing game = a winning game. Inspired by this paradox, a recent study [J. Almeida, D. Peralta-Salas, M. Romera, Can two chaotic systems give rise to order? Physica D 200 (2005) 124-132] asked an analogous question in discrete time dynamical system: can two chaotic systems give rise to order, namely can they be combined into another dynamical system which does not behave chaotically? Numerical evidence is provided in [J. Almeida, D. Peralta-Salas, M. Romera, Can two chaotic systems give rise to order? Physica D 200 (2005) 124-132] that two chaotic quadratic maps, when composed with each other, create a new dynamical system which has a stable period orbit. The question of what happens in the case of random composition of maps is posed in [J. Almeida, D. Peralta-Salas, M. Romera, Can two chaotic systems give rise to order? Physica D 200 (2005) 124-132] but left unanswered. In this note we present an example of a dynamical system where, at each iteration, a map is chosen in a probabilistic manner from a collection of chaotic maps. The resulting random map is proved to have an infinite absolutely continuous invariant measure (acim) with spikes at two points. From this we show that the dynamics behaves in a nearly ordered manner. When the foregoing maps are applied one after the other, deterministically as in [O.E. Percus, J.K. Percus, Can two wrongs make a right? Coin-tossing games and Parrondo’s paradox, Math. Intelligencer 24 (3) (2002) 68-72], the resulting composed map has a periodic orbit which is stable.

Evaluating the Variations in the Flood Susceptibility Maps Accuracies due to the Alterations in the Type and Extent of the Flood Inventory

NASA Astrophysics Data System (ADS)

Tehrany, M. Sh.; Jones, S.

2017-10-01

This paper explores the influence of the extent and density of the inventory data on the final outcomes. This study aimed to examine the impact of different formats and extents of the flood inventory data on the final susceptibility map. An extreme 2011 Brisbane flood event was used as the case study. LR model was applied using polygon and point formats of the inventory data. Random points of 1000, 700, 500, 300, 100 and 50 were selected and susceptibility mapping was undertaken using each group of random points. To perform the modelling Logistic Regression (LR) method was selected as it is a very well-known algorithm in natural hazard modelling due to its easily understandable, rapid processing time and accurate measurement approach. The resultant maps were assessed visually and statistically using Area under Curve (AUC) method. The prediction rates measured for susceptibility maps produced by polygon, 1000, 700, 500, 300, 100 and 50 random points were 63 %, 76 %, 88 %, 80 %, 74 %, 71 % and 65 % respectively. Evidently, using the polygon format of the inventory data didn't lead to the reasonable outcomes. In the case of random points, raising the number of points consequently increased the prediction rates, except for 1000 points. Hence, the minimum and maximum thresholds for the extent of the inventory must be set prior to the analysis. It is concluded that the extent and format of the inventory data are also two of the influential components in the precision of the modelling.

A population 'consensus', partial linkage map of Picea abies Karst. based on RAPD markers

Treesearch

G. Bucci; Thomas L. Kubisiak; W.L. Nance; P. Menozzi

1997-01-01

The authors built a "consensus" partial linkage map based on RAPD markers using 48 sibships of eight megagametophytes each from a natural population of Norway spruce. A RAPD linkage map for a single individual from the same population had previously been constructed. Using 30 random decamers that had yielded 83 RAPD markers in the single-tree map, eight...

Random-breakage mapping method applied to human DNA sequences

NASA Technical Reports Server (NTRS)

Lobrich, M.; Rydberg, B.; Cooper, P. K.; Chatterjee, A. (Principal Investigator)

1996-01-01

The random-breakage mapping method [Game et al. (1990) Nucleic Acids Res., 18, 4453-4461] was applied to DNA sequences in human fibroblasts. The methodology involves NotI restriction endonuclease digestion of DNA from irradiated calls, followed by pulsed-field gel electrophoresis, Southern blotting and hybridization with DNA probes recognizing the single copy sequences of interest. The Southern blots show a band for the unbroken restriction fragments and a smear below this band due to radiation induced random breaks. This smear pattern contains two discontinuities in intensity at positions that correspond to the distance of the hybridization site to each end of the restriction fragment. By analyzing the positions of those discontinuities we confirmed the previously mapped position of the probe DXS1327 within a NotI fragment on the X chromosome, thus demonstrating the validity of the technique. We were also able to position the probes D21S1 and D21S15 with respect to the ends of their corresponding NotI fragments on chromosome 21. A third chromosome 21 probe, D21S11, has previously been reported to be close to D21S1, although an uncertainty about a second possible location existed. Since both probes D21S1 and D21S11 hybridized to a single NotI fragment and yielded a similar smear pattern, this uncertainty is removed by the random-breakage mapping method.

Qualitatively Assessing Randomness in SVD Results

NASA Astrophysics Data System (ADS)

Lamb, K. W.; Miller, W. P.; Kalra, A.; Anderson, S.; Rodriguez, A.

2012-12-01

Singular Value Decomposition (SVD) is a powerful tool for identifying regions of significant co-variability between two spatially distributed datasets. SVD has been widely used in atmospheric research to define relationships between sea surface temperatures, geopotential height, wind, precipitation and streamflow data for myriad regions across the globe. A typical application for SVD is to identify leading climate drivers (as observed in the wind or pressure data) for a particular hydrologic response variable such as precipitation, streamflow, or soil moisture. One can also investigate the lagged relationship between a climate variable and the hydrologic response variable using SVD. When performing these studies it is important to limit the spatial bounds of the climate variable to reduce the chance of random co-variance relationships being identified. On the other hand, a climate region that is too small may ignore climate signals which have more than a statistical relationship to a hydrologic response variable. The proposed research seeks to identify a qualitative method of identifying random co-variability relationships between two data sets. The research identifies the heterogeneous correlation maps from several past results and compares these results with correlation maps produced using purely random and quasi-random climate data. The comparison identifies a methodology to determine if a particular region on a correlation map may be explained by a physical mechanism or is simply statistical chance.

Linkage analysis by genotyping of sibling populations: a genetic map for the potato cyst nematode constructed using a "pseudo-F2" mapping strategy.

PubMed

Rouppe van der Voort, J N; van Eck, H J; van Zandvoort, P M; Overmars, H; Helder, J; Bakker, J

1999-07-01

A mapping strategy is described for the construction of a linkage map of a non-inbred species in which individual offspring genotypes are not amenable to marker analysis. After one extra generation of random mating, the segregating progeny was propagated, and bulked populations of offspring were analyzed. Although the resulting population structure is different from that of commonly used mapping populations, we show that the maximum likelihood formula for a normal F2 is applicable for the estimation of recombination. This "pseudo-F2" mapping strategy, in combination with the development of an AFLP assay for single cysts, facilitated the construction of a linkage map for the potato cyst nematode Globodera rostochiensis. Using 12 pre-selected AFLP primer combinations, a total of 66 segregating markers were identified, 62 of which were mapped to nine linkage groups. These 62 AFLP markers are randomly distributed and cover about 65% of the genome. An estimate of the physical size of the Globodera genome was obtained from comparisons of the number of AFLP fragments obtained with the values for Caenorhabditis elegans. The methodology presented here resulted in the first genomic map for a cyst nematode. The low value of the kilobase/centimorgan (kb/cM) ratio for the Globodera genome will facilitate map-based cloning of genes that mediate the interaction between the nematode and its host plant.

Unitary scintillation detector and system

DOEpatents

McElhaney, Stephanie A.; Chiles, Marion M.

1994-01-01

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations.

Hidden Entanglement and Unitarity at the Planck Scale

NASA Astrophysics Data System (ADS)

Arzano, Michele; Hamma, Alioscia; Severini, Simone

Attempts to go beyond the framework of local quantum field theory include scenarios in which the action of external symmetries on the quantum fields Hilbert space is deformed. We show how the Fock spaces of such theories exhibit a richer structure in their multi-particle sectors. When the deformation scale is proportional to the Planck energy, such new structure leads to the emergence of a "planckian" mode-entanglement, invisible to an observer that cannot probe the Planck scale. To the same observer, certain unitary processes would appear non-unitary. We show how entanglement transfer to the additional degrees of freedom can provide a potential way out of the black hole information paradox.

Berry phase and entanglement of three qubits in a new Yang-Baxter system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu Taotao; Xue Kang; Wu Chunfeng

2009-08-15

In this paper we construct a new 8x8M matrix from the 4x4M matrix, where M/M is the image of the braid group representation. The 8x8M matrix and the 4x4M matrix both satisfy extraspecial 2-group algebra relations. By Yang-Baxteration approach, we derive a unitary R({theta},{phi}) matrix from the M matrix with parameters {phi} and {theta}. Three-qubit entangled states can be generated by using the R({theta},{phi}) matrix. A Hamiltonian for three qubits is constructed from the unitary R({theta},{phi}) matrix. We then study the entanglement and Berry phase of the Yang-Baxter system.

Quantum Standard Teleportation Based on the Generic Measurement Bases

NASA Astrophysics Data System (ADS)

Hao, San-Ru; Hou, Bo-Yu; Xi, Xiao-Qiang; Yue, Rui-Hong

2003-10-01

We study the quantum standard teleportation based on the generic measurement bases. It is shown that the quantum standard teleportation does not depend on the explicit expression of the measurement bases. We have given the correspondence relation between the measurement performed by Alice and the unitary transformation performed by Bob. We also prove that the single particle unknown states and the two-particle unknown cat-like states can be exactly transmitted by means of the generic measurement bases and the correspondence unitary transformations. The project supported in part by National Natural Science Foundation of China, the Hunan Provincial Natural Science Foundation of China, and the Scientific Research Fund of Hunan Provincial Education Department

Probabilistic Teleportation of One-Particle State of S-level

NASA Astrophysics Data System (ADS)

Yan, Feng-Li; Bai, Yan-Kui

2003-09-01

A scheme for probabilistically teleporting an unknown one-particle state of S-level by a group of pairs of partially entangled 2-level particle state is proposed. In this scheme unitary transformation and local measurement take the place of Bell state measurement, then proper unitary transformation and the measurement on an auxiliary qubit with the aid of classical communication are performed. In this way the unknown one-particle state of S-level can be transferred onto a group of remote 2-level particles with certain probability. Furthermore, the receiver can recover the initial signal state on an S-level particle at his hand. The project supported by Natural Science Foundation of Hebei Province of China

Distilling Gaussian states with Gaussian operations is impossible.

PubMed

Eisert, J; Scheel, S; Plenio, M B

2002-09-23

We show that no distillation protocol for Gaussian quantum states exists that relies on (i) arbitrary local unitary operations that preserve the Gaussian character of the state and (ii) homodyne detection together with classical communication and postprocessing by means of local Gaussian unitary operations on two symmetric identically prepared copies. This is in contrast to the finite-dimensional case, where entanglement can be distilled in an iterative protocol using two copies at a time. The ramifications for the distribution of Gaussian states over large distances will be outlined. We also comment on the generality of the approach and sketch the most general form of a Gaussian local operation with classical communication in a bipartite setting.

3d expansions of 5d instanton partition functions

NASA Astrophysics Data System (ADS)

Nieri, Fabrizio; Pan, Yiwen; Zabzine, Maxim

2018-04-01

We propose a set of novel expansions of Nekrasov's instanton partition functions. Focusing on 5d supersymmetric pure Yang-Mills theory with unitary gauge group on C_{q,{t}^{-1}}^2× S^1 , we show that the instanton partition function admits expansions in terms of partition functions of unitary gauge theories living on the 3d subspaces C_q× S^1 , C_{t^{-1}}× S^1 and their intersection along S^1 . These new expansions are natural from the BPS/CFT viewpoint, as they can be matched with W q,t correlators involving an arbitrary number of screening charges of two kinds. Our constructions generalize and interpolate existing results in the literature.

Entropic cohering power in quantum operations

NASA Astrophysics Data System (ADS)

Xi, Zhengjun; Hu, Ming-Liang; Li, Yongming; Fan, Heng

2018-02-01

Coherence is a basic feature of quantum systems and a common necessary condition for quantum correlations. It is also an important physical resource in quantum information processing. In this paper, using relative entropy, we consider a more general definition of the cohering power of quantum operations. First, we calculate the cohering power of unitary quantum operations and show that the amount of distributed coherence caused by non-unitary quantum operations cannot exceed the quantum-incoherent relative entropy between system of interest and its environment. We then find that the difference between the distributed coherence and the cohering power is larger than the quantum-incoherent relative entropy. As an application, we consider the distributed coherence caused by purification.

Extracting observables from lattice data in the three-particle sector

NASA Astrophysics Data System (ADS)

Rusetsky, Akaki; Hammer, Hans-Werner; Pang, Jin-Yi

2018-03-01

The three-particle quantization condition is derived, using the particle-dimer picture in the non-relativistic effective field theory. The procedure for the extraction of various observables in the three-particle sector (the particle-dimer scattering amplitudes, breakup amplitudes, etc.) from the finite-volume lattice spectrum is discussed in detail. As an illustration of the general formalism, the expression for the finite-volume energy shift of the three-body bound-state in the unitary limit is re-derived. The role of the threebody force, which is essential for the renormalization, is highlighted, and the extension of the result beyond the unitary limit is studied. Comparison with other approaches, known in the literature, is carried out.

Supersonic Retropropulsion CFD Validation with Ames Unitary Plan Wind Tunnel Test Data

NASA Technical Reports Server (NTRS)

Schauerhamer, Daniel G.; Zarchi, Kerry A.; Kleb, William L.; Edquist, Karl T.

2013-01-01

A validation study of Computational Fluid Dynamics (CFD) for Supersonic Retropropulsion (SRP) was conducted using three Navier-Stokes flow solvers (DPLR, FUN3D, and OVERFLOW). The study compared results from the CFD codes to each other and also to wind tunnel test data obtained in the NASA Ames Research Center 90 70 Unitary PlanWind Tunnel. Comparisons include surface pressure coefficient as well as unsteady plume effects, and cover a range of Mach numbers, levels of thrust, and angles of orientation. The comparisons show promising capability of CFD to simulate SRP, and best agreement with the tunnel data exists for the steadier cases of the 1-nozzle and high thrust 3-nozzle configurations.

Results of the NASA/MSFC FA-23 plume technology test program performed in the NASA/Ames unitary wind tunnels

NASA Technical Reports Server (NTRS)

Hendershot, K. C.

1977-01-01

A 2.25% scale model of the space shuttle external tank and solid rocket boosters was tested in the NASA/Ames Unitary 11 x 11 foot transonic and 9 x 7 foot supersonic tunnels to obtain base pressure data with firing solid propellant exhaust plumes. Data system difficulties prevented the acquisition of any useful data in the 9 x 7 tunnel. However, 28 successful rocket test firings were made in the 11 x 11 tunnel, providing base pressure data at Mach numbers of 0.5, 0.9, 1.05, 1.2, and 1.3 and at plume pressure ratios ranging from 11 to 89.

On the debate about teleology in biology: the notion of "teleological obstacle".

PubMed

Ribeiro, Manuel Gustavo Leitão; Larentis, Ariane Leites; Caldas, Lúcio Ayres; Garcia, Tomás Coelho; Terra, Letícia Labati; Herbst, Marcelo Hawrylak; Almeida, Rodrigo Volcan

2015-12-01

Among the epistemological obstacles described by Gaston Bachelard, we contend that unitary and pragmatic knowledge is correlated to the teleological categories of Ernst Mayr and is the basis for prevailing debate on the notion of "function" in biology. Given the proximity of the aspects highlighted by these authors, we propose to associate the role of teleological thinking in biology and the notion of unitary and pragmatic knowledge as an obstacle to scientific knowledge. Thus, teleological thinking persists acting as an epistemological obstacle in biology, according to Bachelardian terminology. Our investigation led us to formulate the "teleological obstacle," which we consider important for the future of biology and possibly other sciences.

Description and calibration of the Langley unitary plan wind tunnel

NASA Technical Reports Server (NTRS)

Jackson, C. M., Jr.; Corlett, W. A.; Monta, W. J.

1981-01-01

The two test sections of the Langley Unitary Plan Wind Tunnel were calibrated over the operating Mach number range from 1.47 to 4.63. The results of the calibration are presented along with a a description of the facility and its operational capability. The calibrations include Mach number and flow angularity distributions in both test sections at selected Mach numbers and tunnel stagnation pressures. Calibration data are also presented on turbulence, test-section boundary layer characteristics, moisture effects, blockage, and stagnation-temperature distributions. The facility is described in detail including dimensions and capacities where appropriate, and example of special test capabilities are presented. The operating parameters are fully defined and the power consumption characteristics are discussed.

Unitary easy quantum groups: Geometric aspects

NASA Astrophysics Data System (ADS)

Banica, Teodor

2018-03-01

We discuss the classification problem for the unitary easy quantum groups, under strong axioms, of noncommutative geometric nature. Our main results concern the intermediate easy quantum groups ON ⊂ G ⊂ UN+ . To any such quantum group we associate its Schur-Weyl twist G ¯ , two noncommutative spheres S , S ¯ , a noncommutative torus T, and a quantum reflection group K. Studying (S , S ¯ , T , K , G , G ¯) leads then to some natural axioms, which can be used in order to investigate G itself. We prove that the main examples are covered by our formalism, and we conjecture that in what concerns the case UN ⊂ G ⊂ UN+ , our axioms should restrict the list of known examples.

Unitary scintillation detector and system

DOEpatents

McElhaney, S.A.; Chiles, M.M.

1994-05-31

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations. 10 figs.

Object-based random forest classification of Landsat ETM+ and WorldView-2 satellite imagery for mapping lowland native grassland communities in Tasmania, Australia

NASA Astrophysics Data System (ADS)

Melville, Bethany; Lucieer, Arko; Aryal, Jagannath

2018-04-01

This paper presents a random forest classification approach for identifying and mapping three types of lowland native grassland communities found in the Tasmanian Midlands region. Due to the high conservation priority assigned to these communities, there has been an increasing need to identify appropriate datasets that can be used to derive accurate and frequently updateable maps of community extent. Therefore, this paper proposes a method employing repeat classification and statistical significance testing as a means of identifying the most appropriate dataset for mapping these communities. Two datasets were acquired and analysed; a Landsat ETM+ scene, and a WorldView-2 scene, both from 2010. Training and validation data were randomly subset using a k-fold (k = 50) approach from a pre-existing field dataset. Poa labillardierei, Themeda triandra and lowland native grassland complex communities were identified in addition to dry woodland and agriculture. For each subset of randomly allocated points, a random forest model was trained based on each dataset, and then used to classify the corresponding imagery. Validation was performed using the reciprocal points from the independent subset that had not been used to train the model. Final training and classification accuracies were reported as per class means for each satellite dataset. Analysis of Variance (ANOVA) was undertaken to determine whether classification accuracy differed between the two datasets, as well as between classifications. Results showed mean class accuracies between 54% and 87%. Class accuracy only differed significantly between datasets for the dry woodland and Themeda grassland classes, with the WorldView-2 dataset showing higher mean classification accuracies. The results of this study indicate that remote sensing is a viable method for the identification of lowland native grassland communities in the Tasmanian Midlands, and that repeat classification and statistical significant testing can be used to identify optimal datasets for vegetation community mapping.

A method to estimate the effect of deformable image registration uncertainties on daily dose mapping

PubMed Central

Murphy, Martin J.; Salguero, Francisco J.; Siebers, Jeffrey V.; Staub, David; Vaman, Constantin

2012-01-01

Purpose: To develop a statistical sampling procedure for spatially-correlated uncertainties in deformable image registration and then use it to demonstrate their effect on daily dose mapping. Methods: Sequential daily CT studies are acquired to map anatomical variations prior to fractionated external beam radiotherapy. The CTs are deformably registered to the planning CT to obtain displacement vector fields (DVFs). The DVFs are used to accumulate the dose delivered each day onto the planning CT. Each DVF has spatially-correlated uncertainties associated with it. Principal components analysis (PCA) is applied to measured DVF error maps to produce decorrelated principal component modes of the errors. The modes are sampled independently and reconstructed to produce synthetic registration error maps. The synthetic error maps are convolved with dose mapped via deformable registration to model the resulting uncertainty in the dose mapping. The results are compared to the dose mapping uncertainty that would result from uncorrelated DVF errors that vary randomly from voxel to voxel. Results: The error sampling method is shown to produce synthetic DVF error maps that are statistically indistinguishable from the observed error maps. Spatially-correlated DVF uncertainties modeled by our procedure produce patterns of dose mapping error that are different from that due to randomly distributed uncertainties. Conclusions: Deformable image registration uncertainties have complex spatial distributions. The authors have developed and tested a method to decorrelate the spatial uncertainties and make statistical samples of highly correlated error maps. The sample error maps can be used to investigate the effect of DVF uncertainties on daily dose mapping via deformable image registration. An initial demonstration of this methodology shows that dose mapping uncertainties can be sensitive to spatial patterns in the DVF uncertainties. PMID:22320766

Dense genetic linkage maps of three Populus species (Populus deltoides, P. nigra and P. trichocarpa) based on AFLP and microsatellite markers.

PubMed

Cervera, M T; Storme, V; Ivens, B; Gusmão, J; Liu, B H; Hostyn, V; Van Slycken, J; Van Montagu, M; Boerjan, W

2001-06-01

Populus deltoides, P. nigra, and P. trichocarpa are the most important species for poplar breeding programs worldwide. In addition, Populus has become a model for fundamental research on trees. Linkage maps were constructed for these three species by analyzing progeny of two controlled crosses sharing the same female parent, Populus deltoides cv. S9-2 x P. nigra cv. Ghoy and P. deltoides cv. S9-2 x P. trichocarpa cv. V24. The two-way pseudotestcross mapping strategy was used to construct the maps. Amplified fragment length polymorphism (AFLP) markers that segregated 1:1 were used to form the four parental maps. Microsatellites and sequence-tagged sites were used to align homoeologous groups between the maps and to merge linkage groups within the individual maps. Linkage analysis and alignment of the homoeologous groups resulted in 566 markers distributed over 19 groups for P. deltoides covering 86% of the genome, 339 markers distributed over 19 groups for P. trichocarpa covering 73%, and 369 markers distributed over 28 groups for P. nigra covering 61%. Several tests for randomness showed that the AFLP markers were randomly distributed over the genome.

Dense genetic linkage maps of three Populus species (Populus deltoides, P. nigra and P. trichocarpa) based on AFLP and microsatellite markers.

PubMed Central

Cervera, M T; Storme, V; Ivens, B; Gusmão, J; Liu, B H; Hostyn, V; Van Slycken, J; Van Montagu, M; Boerjan, W

2001-01-01

Populus deltoides, P. nigra, and P. trichocarpa are the most important species for poplar breeding programs worldwide. In addition, Populus has become a model for fundamental research on trees. Linkage maps were constructed for these three species by analyzing progeny of two controlled crosses sharing the same female parent, Populus deltoides cv. S9-2 x P. nigra cv. Ghoy and P. deltoides cv. S9-2 x P. trichocarpa cv. V24. The two-way pseudotestcross mapping strategy was used to construct the maps. Amplified fragment length polymorphism (AFLP) markers that segregated 1:1 were used to form the four parental maps. Microsatellites and sequence-tagged sites were used to align homoeologous groups between the maps and to merge linkage groups within the individual maps. Linkage analysis and alignment of the homoeologous groups resulted in 566 markers distributed over 19 groups for P. deltoides covering 86% of the genome, 339 markers distributed over 19 groups for P. trichocarpa covering 73%, and 369 markers distributed over 28 groups for P. nigra covering 61%. Several tests for randomness showed that the AFLP markers were randomly distributed over the genome. PMID:11404342

Quantum simulation from the bottom up: the case of rebits

NASA Astrophysics Data System (ADS)

Enshan Koh, Dax; Yuezhen Niu, Murphy; Yoder, Theodore J.

2018-05-01

Typically, quantum mechanics is thought of as a linear theory with unitary evolution governed by the Schrödinger equation. While this is technically true and useful for a physicist, with regards to computation it is an unfortunately narrow point of view. Just as a classical computer can simulate highly nonlinear functions of classical states, so too can the more general quantum computer simulate nonlinear evolutions of quantum states. We detail one particular simulation of nonlinearity on a quantum computer, showing how the entire class of -unitary evolutions (on n qubits) can be simulated using a unitary, real-amplitude quantum computer (consisting of n  +  1 qubits in total). These operators can be represented as the sum of a linear and antilinear operator, and add an intriguing new set of nonlinear quantum gates to the toolbox of the quantum algorithm designer. Furthermore, a subgroup of these nonlinear evolutions, called the -Cliffords, can be efficiently classically simulated, by making use of the fact that Clifford operators can simulate non-Clifford (in fact, non-linear) operators. This perspective of using the physical operators that we have to simulate non-physical ones that we do not is what we call bottom-up simulation, and we give some examples of its broader implications.

Realization of the three-qubit quantum controlled gate based on matching Hermitian generators

NASA Astrophysics Data System (ADS)

Gautam, Kumar; Rawat, Tarun Kumar; Parthasarathy, Harish; Sharma, Navneet; Upadhyaya, Varun

2017-05-01

This paper deals with the design of quantum unitary gate by matching the Hermitian generators. A given complicated quantum controlled gate is approximated by perturbing a simple quantum system with a small time-varying potential. The basic idea is to evaluate the generator H_φ of the perturbed system approximately using first-order perturbation theory in the interaction picture. H_φ depends on a modulating signal φ(t){:} 0≤t≤T which modulates a known potential V. The generator H_φ of the given gate U_g is evaluated using H_g=ι log U_g. The optimal modulating signal φ(t) is chosen so that \\Vert H_g - H_φ \\Vert is a minimum. The simple quantum system chosen for our simulation is harmonic oscillator with charge perturbed by an electric field that is a constant in space but time varying and is controlled externally. This is used to approximate the controlled unitary gate obtained by perturbing the oscillator with an anharmonic term proportional to q^3. Simulations results show significantly small noise-to-signal ratio. Finally, we discuss how the proposed method is particularly suitable for designing some commonly used unitary gates. Another example was chosen to illustrate this method of gate design is the ion-trap model.

First unitary, then divided: the temporal dynamics of dividing attention.

PubMed

Jefferies, Lisa N; Witt, Joseph B

2018-04-24

Whether focused visual attention can be divided has been the topic of much investigation, and there is a compelling body of evidence showing that, at least under certain conditions, attention can be divided and deployed as two independent foci. Three experiments were conducted to examine whether attention can be deployed in divided form from the outset, or whether it is first deployed as a unitary focus before being divided. To test this, we adapted the methodology of Jefferies, Enns, and Di Lollo (Journal of Experimental Psychology: Human Perception and Performance 40: 465, 2014), who used a dual-stream Attentional Blink paradigm and two letter-pair targets. One aspect of the AB, Lag-1 sparing, has been shown to occur only if the second target pair appears within the focus of attention. By presenting the second target pair at various spatial locations and assessing the magnitude of Lag-1 sparing, we probed the spatial distribution of attention. By systematically manipulating the stimulus-onset-asynchrony between the targets, we also tracked changes to the spatial distribution of attention over time. The results showed that even under conditions which encourage the division of attention, the attentional focus is first deployed in unitary form before being divided. It is then maintained in divided form only briefly before settling on a single location.

Prototype muon detectors for the AMIGA component of the Pierre Auger Observatory

DOE PAGES

Aab, Alexander

2016-02-17

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to extend its range of detection and to directly measure the muon content of the particle showers. It consists of an infill of surface water-Cherenkov detectors accompanied by buried scintillator detectors used for muon counting. The main objectives of the AMIGA engineering array, referred to as the Unitary Cell, are to identify and resolve all engineering issues as well as to understand the muon-number counting uncertainties related to the design of the detector. The mechanical design, fabrication and deployment processes of the muonmore » counters of the Unitary Cell are described in this document. These muon counters modules comprise sealed PVC casings containing plastic scintillation bars, wavelength-shifter optical fibers, 64 pixel photomultiplier tubes, and acquisition electronics. The modules are buried approximately 2.25 m below ground level in order to minimize contamination from electromagnetic shower particles. The mechanical setup, which allows access to the electronics for maintenance, is also described in addition to tests of the modules' response and integrity. As a result, the completed Unitary Cell has measured a number of air showers of which a first analysis of a sample event is included here.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernando, Sudarshan; Günaydin, Murat

We study the minimal unitary representation (minrep) of SO(5, 2), obtained by quantization of its geometric quasiconformal action, its deformations and supersymmetric extensions. The minrep of SO(5, 2) describes a massless conformal scalar field in five dimensions and admits a unique “deformation” which describes a massless conformal spinor. Scalar and spinor minreps of SO(5, 2) are the 5d analogs of Dirac’s singletons of SO(3, 2). We then construct the minimal unitary representation of the unique 5d supercon-formal algebra F(4) with the even subalgebra SO(5, 2) ×SU(2). The minrep of F(4) describes a massless conformal supermultiplet consisting of two scalar andmore » one spinor fields. We then extend our results to the construction of higher spin AdS 6/CFT 5 (super)-algebras. The Joseph ideal of the minrep of SO(5, 2) vanishes identically as operators and hence its enveloping algebra yields the AdS 6/CFT 5 bosonic higher spin algebra directly. The enveloping algebra of the spinor minrep defines a “deformed” higher spin algebra for which a deformed Joseph ideal vanishes identically as operators. These results are then extended to the construction of the unique higher spin AdS 6/CFT 5 superalgebra as the enveloping algebra of the minimal unitary realization of F(4) obtained by the quasiconformal methods.« less

The supersymmetric method in random matrix theory and applications to QCD

NASA Astrophysics Data System (ADS)

Verbaarschot, Jacobus

2004-12-01

The supersymmetric method is a powerful method for the nonperturbative evaluation of quenched averages in disordered systems. Among others, this method has been applied to the statistical theory of S-matrix fluctuations, the theory of universal conductance fluctuations and the microscopic spectral density of the QCD Dirac operator. We start this series of lectures with a general review of Random Matrix Theory and the statistical theory of spectra. An elementary introduction of the supersymmetric method in Random Matrix Theory is given in the second and third lecture. We will show that a Random Matrix Theory can be rewritten as an integral over a supermanifold. This integral will be worked out in detail for the Gaussian Unitary Ensemble that describes level correlations in systems with broken time-reversal invariance. We especially emphasize the role of symmetries. As a second example of the application of the supersymmetric method we discuss the calculation of the microscopic spectral density of the QCD Dirac operator. This is the eigenvalue density near zero on the scale of the average level spacing which is known to be given by chiral Random Matrix Theory. Also in this case we use symmetry considerations to rewrite the generating function for the resolvent as an integral over a supermanifold. The main topic of the second last lecture is the recent developments on the relation between the supersymmetric partition function and integrable hierarchies (in our case the Toda lattice hierarchy). We will show that this relation is an efficient way to calculate superintegrals. Several examples that were given in previous lectures will be worked out by means of this new method. Finally, we will discuss the quenched QCD Dirac spectrum at nonzero chemical potential. Because of the nonhermiticity of the Dirac operator the usual supersymmetric method has not been successful in this case. However, we will show that the supersymmetric partition function can be evaluated by means of the replica limit of the Toda lattice equation.

Differential recruitment of executive resources during mind wandering.

PubMed

Kam, Julia W Y; Handy, Todd C

2014-05-01

Recent research has shown that mind wandering recruits executive resources away from the external task towards inner thoughts. No studies however have determined whether executive functions are drawn away in a unitary manner during mind wandering episodes, or whether there is variation in specific functions impacted. Accordingly, we examined whether mind wandering differentially modulates three core executive functions-response inhibition, updating of working memory, and mental set shifting. In three experiments, participants performed one of these three executive function tasks and reported their attentional state as either on-task or mind wandering at random intervals. We found that mind wandering led to poorer performance in the response inhibition and working memory tasks, but not the set-shifting task. These findings suggest that mind wandering does not recruit executive functions in a monolithic manner. Rather, it appears to selectively engage certain executive functions, which may reflect the adaptive maintenance of ongoing task performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Blending Determinism with Evolutionary Computing: Applications to the Calculation of the Molecular Electronic Structure of Polythiophene.

PubMed

Sarkar, Kanchan; Sharma, Rahul; Bhattacharyya, S P

2010-03-09

A density matrix based soft-computing solution to the quantum mechanical problem of computing the molecular electronic structure of fairly long polythiophene (PT) chains is proposed. The soft-computing solution is based on a "random mutation hill climbing" scheme which is modified by blending it with a deterministic method based on a trial single-particle density matrix [P((0))(R)] for the guessed structural parameters (R), which is allowed to evolve under a unitary transformation generated by the Hamiltonian H(R). The Hamiltonian itself changes as the geometrical parameters (R) defining the polythiophene chain undergo mutation. The scale (λ) of the transformation is optimized by making the energy [E(λ)] stationary with respect to λ. The robustness and the performance levels of variants of the algorithm are analyzed and compared with those of other derivative free methods. The method is further tested successfully with optimization of the geometry of bipolaron-doped long PT chains.

Quantum subsystems: Exploring the complementarity of quantum privacy and error correction

NASA Astrophysics Data System (ADS)

Jochym-O'Connor, Tomas; Kribs, David W.; Laflamme, Raymond; Plosker, Sarah

2014-09-01

This paper addresses and expands on the contents of the recent Letter [Phys. Rev. Lett. 111, 030502 (2013), 10.1103/PhysRevLett.111.030502] discussing private quantum subsystems. Here we prove several previously presented results, including a condition for a given random unitary channel to not have a private subspace (although this does not mean that private communication cannot occur, as was previously demonstrated via private subsystems) and algebraic conditions that characterize when a general quantum subsystem or subspace code is private for a quantum channel. These conditions can be regarded as the private analog of the Knill-Laflamme conditions for quantum error correction, and we explore how the conditions simplify in some special cases. The bridge between quantum cryptography and quantum error correction provided by complementary quantum channels motivates the study of a new, more general definition of quantum error-correcting code, and we initiate this study here. We also consider the concept of complementarity for the general notion of a private quantum subsystem.

Real-Time Imaging Reveals Properties of Glutamate-Induced Arc/Arg 3.1 Translation in Neuronal Dendrites.

PubMed

Na, Youn; Park, Sungjin; Lee, Changhee; Kim, Dong-Kyu; Park, Joo Min; Sockanathan, Shanthini; Huganir, Richard L; Worley, Paul F

2016-08-03

The immediate early gene Arc (also Arg3.1) produces rapid changes in synaptic properties that are linked to de novo translation. Here we develop a novel translation reporter that exploits the rapid maturation and "flash" kinetics of Gaussia luciferase (Gluc) to visualize Arc translation. Following glutamate stimulation, discrete Arc-Gluc bioluminescent flashes representing sites of de novo translation are detected within 15 s at distributed sites in dendrites, but not spines. Flashes are episodic, lasting ∼20 s, and may be unitary or repeated at ∼minute intervals at the same sites. Analysis of flash amplitudes suggests they represent the quantal product of one or more polyribosomes, while inter-flash intervals appear random, suggesting they arise from a stochastic process. Surprisingly, glutamate-induced translation is dependent on Arc open reading frame. Combined observations support a model in which stalled ribosomes are reactivated to rapidly generate Arc protein. Copyright © 2016 Elsevier Inc. All rights reserved.

Process, System, Causality, and Quantum Mechanics: A Psychoanalysis of Animal Faith

NASA Astrophysics Data System (ADS)

Etter, Tom; Noyes, H. Pierre

We shall argue in this paper that a central piece of modern physics does not really belong to physics at all but to elementary probability theory. Given a joint probability distribution J on a set of random variables containing x and y, define a link between x and y to be the condition x=y on J. Define the {\\it state} D of a link x=y as the joint probability distribution matrix on x and y without the link. The two core laws of quantum mechanics are the Born probability rule, and the unitary dynamical law whose best known form is the Schrodinger's equation. Von Neumann formulated these two laws in the language of Hilbert space as prob(P) = trace(PD) and D'T = TD respectively, where P is a projection, D and D' are (von Neumann) density matrices, and T is a unitary transformation. We'll see that if we regard link states as density matrices, the algebraic forms of these two core laws occur as completely general theorems about links. When we extend probability theory by allowing cases to count negatively, we find that the Hilbert space framework of quantum mechanics proper emerges from the assumption that all D's are symmetrical in rows and columns. On the other hand, Markovian systems emerge when we assume that one of every linked variable pair has a uniform probability distribution. By representing quantum and Markovian structure in this way, we see clearly both how they differ, and also how they can coexist in natural harmony with each other, as they must in quantum measurement, which we'll examine in some detail. Looking beyond quantum mechanics, we see how both structures have their special places in a much larger continuum of formal systems that we have yet to look for in nature.

Mapping of medical acronyms and initialisms to Medical Subject Headings (MeSH) across selected systems

PubMed Central

Shultz, Mary

2006-01-01

Introduction: Given the common use of acronyms and initialisms in the health sciences, searchers may be entering these abbreviated terms rather than full phrases when searching online systems. The purpose of this study is to evaluate how various MEDLINE Medical Subject Headings (MeSH) interfaces map acronyms and initialisms to the MeSH vocabulary. Methods: The interfaces used in this study were: the PubMed MeSH database, the PubMed Automatic Term Mapping feature, the NLM Gateway Term Finder, and Ovid MEDLINE. Acronyms and initialisms were randomly selected from 2 print sources. The test data set included 415 randomly selected acronyms and initialisms whose related meanings were found to be MeSH terms. Each acronym and initialism was entered into each MEDLINE MeSH interface to determine if it mapped to the corresponding MeSH term. Separately, 46 commonly used acronyms and initialisms were tested. Results: While performance differed widely, the success rates were low across all interfaces for the randomly selected terms. The common acronyms and initialisms tested at higher success rates across the interfaces, but the differences between the interfaces remained. Conclusion: Online interfaces do not always map medical acronyms and initialisms to their corresponding MeSH phrases. This may lead to inaccurate results and missed information if acronyms and initialisms are used in search strategies. PMID:17082832

Improved predictive mapping of indoor radon concentrations using ensemble regression trees based on automatic clustering of geological units.

PubMed

Kropat, Georg; Bochud, Francois; Jaboyedoff, Michel; Laedermann, Jean-Pascal; Murith, Christophe; Palacios Gruson, Martha; Baechler, Sébastien

2015-09-01

According to estimations around 230 people die as a result of radon exposure in Switzerland. This public health concern makes reliable indoor radon prediction and mapping methods necessary in order to improve risk communication to the public. The aim of this study was to develop an automated method to classify lithological units according to their radon characteristics and to develop mapping and predictive tools in order to improve local radon prediction. About 240 000 indoor radon concentration (IRC) measurements in about 150 000 buildings were available for our analysis. The automated classification of lithological units was based on k-medoids clustering via pair-wise Kolmogorov distances between IRC distributions of lithological units. For IRC mapping and prediction we used random forests and Bayesian additive regression trees (BART). The automated classification groups lithological units well in terms of their IRC characteristics. Especially the IRC differences in metamorphic rocks like gneiss are well revealed by this method. The maps produced by random forests soundly represent the regional difference of IRCs in Switzerland and improve the spatial detail compared to existing approaches. We could explain 33% of the variations in IRC data with random forests. Additionally, the influence of a variable evaluated by random forests shows that building characteristics are less important predictors for IRCs than spatial/geological influences. BART could explain 29% of IRC variability and produced maps that indicate the prediction uncertainty. Ensemble regression trees are a powerful tool to model and understand the multidimensional influences on IRCs. Automatic clustering of lithological units complements this method by facilitating the interpretation of radon properties of rock types. This study provides an important element for radon risk communication. Future approaches should consider taking into account further variables like soil gas radon measurements as well as more detailed geological information. Copyright © 2015 Elsevier Ltd. All rights reserved.

CYP3A4 and CYP3A5 polymorphisms and blood pressure response to amlodipine among African-American men and women with early hypertensive renal disease.

PubMed

Bhatnagar, Vibha; Garcia, Erin P; O'Connor, Daniel T; Brophy, Victoria H; Alcaraz, John; Richard, Erin; Bakris, George L; Middleton, John P; Norris, Keith C; Wright, Jackson; Hiremath, Leena; Contreras, Gabriel; Appel, Lawrence J; Lipkowitz, Michael S

2010-01-01

To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164). Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of < or =107 mm Hg by CYP3A4 (A-392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response. Women randomized to a usual MAP goal with an A allele at CYP3A4 A-392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20-9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17-3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response. Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study. Copyright (c) 2009 S. Karger AG, Basel.

CYP3A4 and CYP3A5 Polymorphisms and Blood Pressure Response to Amlodipine among African-American Men and Women with Early Hypertensive Renal Disease

PubMed Central

Bhatnagar, Vibha; Garcia, Erin P.; O’Connor, Daniel T.; Brophy, Victoria H.; Alcaraz, John; Richard, Erin; Bakris, George L.; Middleton, John P.; Norris, Keith C.; Wright, Jackson; Hiremath, Leena; Contreras, Gabriel; Appel, Lawrence J.; Lipkowitz, Michael S.

2010-01-01

Purpose To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164). Methods Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of ≤107 mm Hg by CYP3A4 (A–392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response. Results Women randomized to a usual MAP goal with an A allele at CYP3A4 A–392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20–9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17–3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response. Conclusions Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study. PMID:19907160

Pore dimensions and the role of occupancy in unitary conductance of Shaker K channels

PubMed Central

Díaz-Franulic, Ignacio; Sepúlveda, Romina V.; Navarro-Quezada, Nieves; González-Nilo, Fernando

2015-01-01

K channels mediate the selective passage of K+ across the plasma membrane by means of intimate interactions with ions at the pore selectivity filter located near the external face. Despite high conservation of the selectivity filter, the K+ transport properties of different K channels vary widely, with the unitary conductance spanning a range of over two orders of magnitude. Mutation of Pro475, a residue located at the cytoplasmic entrance of the pore of the small-intermediate conductance K channel Shaker (Pro475Asp (P475D) or Pro475Gln (P475Q)), increases Shaker’s reported ∼20-pS conductance by approximately six- and approximately threefold, respectively, without any detectable effect on its selectivity. These findings suggest that the structural determinants underlying the diversity of K channel conductance are distinct from the selectivity filter, making P475D and P475Q excellent probes to identify key determinants of the K channel unitary conductance. By measuring diffusion-limited unitary outward currents after unilateral addition of 2 M sucrose to the internal solution to increase its viscosity, we estimated a pore internal radius of capture of ∼0.82 Å for all three Shaker variants (wild type, P475D, and P475Q). This estimate is consistent with the internal entrance of the Kv1.2/2.1 structure if the effective radius of hydrated K+ is set to ∼4 Å. Unilateral exposure to sucrose allowed us to estimate the internal and external access resistances together with that of the inner pore. We determined that Shaker resistance resides mainly in the inner cavity, whereas only ∼8% resides in the selectivity filter. To reduce the inner resistance, we introduced additional aspartate residues into the internal vestibule to favor ion occupancy. No aspartate addition raised the maximum unitary conductance, measured at saturating [K+], beyond that of P475D, suggesting an ∼200-pS conductance ceiling for Shaker. This value is approximately one third of the maximum conductance of the large conductance K (BK) channel (the K channel of highest conductance), reducing the energy gap between their K+ transport rates to ∼1 kT. Thus, although Shaker’s pore sustains ion translocation as the BK channel’s does, higher energetic costs of ion stabilization or higher friction with the ion’s rigid hydration cage in its narrower aqueous cavity may entail higher resistance. PMID:26216859

Unitary IPSPs evoked by interneurons at the stratum radiatum-stratum lacunosum-moleculare border in the CA1 area of the rat hippocampus in vitro

PubMed Central

Vida, Imre; Halasy, Katalin; Szinyei, Csaba; Somogyi, Peter; Buhl, Eberhard H

1998-01-01

Hippocampal non-principal neurons at the stratum radiatum-stratum lacunosum-moleculare border (R-LM interneurons) of the CA1 area may constitute several cell classes and have been implicated in the generation of GABAergic unitary IPSPs. Using biocytin-filled electrodes we recorded R-LM interneurons intracellularly in vitro and determined their postsynaptic effects in concomitantly recorded pyramidal cells. Light microscopic analysis revealed four populations of R-LM interneurons with distinct axons: (1) basket cells (n= 4) with axons predominantly ramifying in the pyramidal cell layer; (2) Schaffer collateral/commissural pathway-associated interneurons (n= 10) stratifying in stratum radiatum and, to a lesser extent, stratum oriens; (3) perforant pathway-associated interneurons (n= 6) innervating the perforant path termination zone in stratum lacunosum-moleculare of the CA1 area as well as equivalent portions of the dentate gyrus and subiculum; and (4) neurogliaform interneurons (n= 2) characterized by their dense, compact axonal and dendritic arbour. Random electron microscopic sampling of synaptic targets revealed a preponderance of pyramidal neurons as postsynaptic elements. Basket cells had a synaptic target preference for somata and proximal dendrites, whereas the remainder of R-LM interneurons innervated dendritic shafts and spines. The axon of dendrite-targeting cells formed up to six putative contacts with individual postsynaptic pyramidal cells. Anatomically recovered R-LM interneurons (n= 22) had a mean resting membrane potential of -56.7 ± 3.6 mV, a membrane time constant of 12.9 ± 7.7 ms and an input resistance of 86.4 ± 29.2 MΩ. Depolarizing current pulses generally elicited overshooting action potentials (70.8 ± 6.9 mV) which had a mean duration, when measured at half-amplitude, of 0.7 ± 0.1 ms. In response to prolonged (> 200 ms) depolarizing current pulses all R-LM interneurons displayed (a varying degree of) spike frequency adaptation. Basket cells, Schaffer-associated and neurogliaform interneurons elicited small-amplitude (< 2 mV), short-latency IPSPs in postsynaptic pyramids (n= 5, 13 and 1, respectively). Those interactions in which an effect was elicited with the repetitive activation of the presynaptic neuron (n= 13) showed a substantial degree of postsynaptic response summation. Unitary IPSPs had fast kinetics and, whenever tested (n= 5; 1 basket cell and 4 Schaffer-associated interneurons), were abolished by the GABAA receptor antagonist bicuculline. Thus, R-LM interneurons comprise several distinct populations which evoke fast GABAA receptor-mediated IPSPs. The domain-specific innervation of postsynaptic pyramidal cells suggests functionally diverse effects on the integration of afferent information in functionally non-equivalent compartments of pyramidal cells. PMID:9503336

Effective Reading Comprehension in EFL Contexts: Individual and Collaborative Concept Mapping Strategies

ERIC Educational Resources Information Center

Riahi, Zahra; Pourdana, Natasha

2017-01-01

The present study attempted to investigate the possible impacts of Individual Concept Mapping (ICM) and Collaborative Concept Mapping (CCM) strategies on Iranian EFL learners' reading comprehension. For this purpose, 90 pre-intermediate female language learners ranged between 12 to 17 years of age were selected to randomly assign into ICM, CCM and…

Effects of Speech Practice on Fast Mapping in Monolingual and Bilingual Speakers

ERIC Educational Resources Information Center

Kan, Pui Fong; Sadagopan, Neeraja; Janich, Lauren; Andrade, Marixa

2014-01-01

Purpose: This study examines the effects of the levels of speech practice on fast mapping in monolingual and bilingual speakers. Method: Participants were 30 English-speaking monolingual and 30 Spanish-English bilingual young adults. Each participant was randomly assigned to 1 of 3 practice conditions prior to the fast-mapping task: (a) intensive…

Depth image super-resolution via semi self-taught learning framework

NASA Astrophysics Data System (ADS)

Zhao, Furong; Cao, Zhiguo; Xiao, Yang; Zhang, Xiaodi; Xian, Ke; Li, Ruibo

2017-06-01

Depth images have recently attracted much attention in computer vision and high-quality 3D content for 3DTV and 3D movies. In this paper, we present a new semi self-taught learning application framework for enhancing resolution of depth maps without making use of ancillary color images data at the target resolution, or multiple aligned depth maps. Our framework consists of cascade random forests reaching from coarse to fine results. We learn the surface information and structure transformations both from a small high-quality depth exemplars and the input depth map itself across different scales. Considering that edge plays an important role in depth map quality, we optimize an effective regularized objective that calculates on output image space and input edge space in random forests. Experiments show the effectiveness and superiority of our method against other techniques with or without applying aligned RGB information

Random waves in the brain: Symmetries and defect generation in the visual cortex

NASA Astrophysics Data System (ADS)

Schnabel, M.; Kaschube, M.; Löwel, S.; Wolf, F.

2007-06-01

How orientation maps in the visual cortex of the brain develop is a matter of long standing debate. Experimental and theoretical evidence suggests that their development represents an activity-dependent self-organization process. Theoretical analysis [1] exploring this hypothesis predicted that maps at an early developmental stage are realizations of Gaussian random fields exhibiting a rigorous lower bound for their densities of topological defects, called pinwheels. As a consequence, lower pinwheel densities, if observed in adult animals, are predicted to develop through the motion and annihilation of pinwheel pairs. Despite of being valid for a large class of developmental models this result depends on the symmetries of the models and thus of the predicted random field ensembles. In [1] invariance of the orientation map's statistical properties under independent space rotations and orientation shifts was assumed. However, full rotation symmetry appears to be broken by interactions of cortical neurons, e.g. selective couplings between groups of neurons with collinear orientation preferences [2]. A recently proposed new symmetry, called shift-twist symmetry [3], stating that spatial rotations have to occur together with orientation shifts in order to be an appropriate symmetry transformation, is more consistent with this organization. Here we generalize our random field approach to this important symmetry class. We propose a new class of shift-twist symmetric Gaussian random fields and derive the general correlation functions of this ensemble. It turns out that despite strong effects of the shift-twist symmetry on the structure of the correlation functions and on the map layout the lower bound on the pinwheel densities remains unaffected, predicting pinwheel annihilation in systems with low pinwheel densities.

Ensembles of physical states and random quantum circuits on graphs

NASA Astrophysics Data System (ADS)

Hamma, Alioscia; Santra, Siddhartha; Zanardi, Paolo

2012-11-01

In this paper we continue and extend the investigations of the ensembles of random physical states introduced in Hamma [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.040502 109, 040502 (2012)]. These ensembles are constructed by finite-length random quantum circuits (RQC) acting on the (hyper)edges of an underlying (hyper)graph structure. The latter encodes for the locality structure associated with finite-time quantum evolutions generated by physical, i.e., local, Hamiltonians. Our goal is to analyze physical properties of typical states in these ensembles; in particular here we focus on proxies of quantum entanglement as purity and α-Renyi entropies. The problem is formulated in terms of matrix elements of superoperators which depend on the graph structure, choice of probability measure over the local unitaries, and circuit length. In the α=2 case these superoperators act on a restricted multiqubit space generated by permutation operators associated to the subsets of vertices of the graph. For permutationally invariant interactions the dynamics can be further restricted to an exponentially smaller subspace. We consider different families of RQCs and study their typical entanglement properties for finite time as well as their asymptotic behavior. We find that area law holds in average and that the volume law is a typical property (that is, it holds in average and the fluctuations around the average are vanishing for the large system) of physical states. The area law arises when the evolution time is O(1) with respect to the size L of the system, while the volume law arises as is typical when the evolution time scales like O(L).

New quantum number for the many-electron Dirac-Coulomb Hamiltonian

NASA Astrophysics Data System (ADS)

Komorovsky, Stanislav; Repisky, Michal; Bučinský, Lukáš

2016-11-01

By breaking the spin symmetry in the relativistic domain, a powerful tool in physical sciences was lost. In this work, we examine an alternative of spin symmetry for systems described by the many-electron Dirac-Coulomb Hamiltonian. We show that the square of many-electron operator K+, defined as a sum of individual single-electron time-reversal (TR) operators, is a linear Hermitian operator which commutes with the Dirac-Coulomb Hamiltonian in a finite Fock subspace. In contrast to the square of a standard unitary many-electron TR operator K , the K+2 has a rich eigenspectrum having potential to substitute spin symmetry in the relativistic domain. We demonstrate that K+ is connected to K through an exponential mapping, in the same way as spin operators are mapped to the spin rotational group. Consequently, we call K+ the generator of the many-electron TR symmetry. By diagonalizing the operator K+2 in the basis of Kramers-restricted Slater determinants, we introduce the relativistic variant of configuration state functions (CSF), denoted as Kramers CSF. A new quantum number associated with K+2 has potential to be used in many areas, for instance, (a) to design effective spin Hamiltonians for electron spin resonance spectroscopy of heavy-element containing systems; (b) to increase efficiency of methods for the solution of many-electron problems in relativistic computational chemistry and physics; (c) to define Kramers contamination in unrestricted density functional and Hartree-Fock theory as a relativistic analog of the spin contamination in the nonrelativistic domain.

A Pause-then-Cancel model of stopping: evidence from basal ganglia neurophysiology

PubMed Central

Berke, Joshua D.

2017-01-01

Many studies have implicated the basal ganglia in the suppression of action impulses (‘stopping’). Here, we discuss recent neurophysiological evidence that distinct hypothesized processes involved in action preparation and cancellation can be mapped onto distinct basal ganglia cell types and pathways. We examine how movement-related activity in the striatum is related to a ‘Go’ process and how going may be modulated by brief epochs of beta oscillations. We then describe how, rather than a unitary ‘Stop’ process, there appear to be separate, complementary ‘Pause’ and ‘Cancel’ mechanisms. We discuss the implications of these stopping subprocesses for the interpretation of the stop-signal reaction time—in particular, some activity that seems too slow to causally contribute to stopping when assuming a single Stop processes may actually be fast enough under a Pause-then-Cancel model. Finally, we suggest that combining complementary neural mechanisms that emphasize speed or accuracy respectively may serve more generally to optimize speed–accuracy trade-offs. This article is part of the themed issue ‘Movement suppression: brain mechanisms for stopping and stillness’. PMID:28242736

A Pause-then-Cancel model of stopping: evidence from basal ganglia neurophysiology.

PubMed

Schmidt, Robert; Berke, Joshua D

2017-04-19

Many studies have implicated the basal ganglia in the suppression of action impulses ('stopping'). Here, we discuss recent neurophysiological evidence that distinct hypothesized processes involved in action preparation and cancellation can be mapped onto distinct basal ganglia cell types and pathways. We examine how movement-related activity in the striatum is related to a 'Go' process and how going may be modulated by brief epochs of beta oscillations. We then describe how, rather than a unitary 'Stop' process, there appear to be separate, complementary 'Pause' and 'Cancel' mechanisms. We discuss the implications of these stopping subprocesses for the interpretation of the stop-signal reaction time-in particular, some activity that seems too slow to causally contribute to stopping when assuming a single Stop processes may actually be fast enough under a Pause-then-Cancel model. Finally, we suggest that combining complementary neural mechanisms that emphasize speed or accuracy respectively may serve more generally to optimize speed-accuracy trade-offs.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'. © 2017 The Author(s).

Two Coincidence Detectors for Spike Timing-Dependent Plasticity in Somatosensory Cortex

PubMed Central

Bender, Vanessa A.; Bender, Kevin J.; Brasier, Daniel J.; Feldman, Daniel E.

2011-01-01

Many cortical synapses exhibit spike timing-dependent plasticity (STDP) in which the precise timing of presynaptic and postsynaptic spikes induces synaptic strengthening [long-term potentiation (LTP)] or weakening [long-term depression (LTD)]. Standard models posit a single, postsynaptic, NMDA receptor-based coincidence detector for LTP and LTD components of STDP. We show instead that STDP at layer 4 to layer 2/3 synapses in somatosensory (S1) cortex involves separate calcium sources and coincidence detection mechanisms for LTP and LTD. LTP showed classical NMDA receptor dependence. LTD was independent of postsynaptic NMDA receptors and instead required group I metabotropic glutamate receptors and calcium from voltage-sensitive channels and IP3 receptor-gated stores. Downstream of postsynaptic calcium, LTD required retrograde endocannabinoid signaling, leading to presynaptic LTD expression, and also required activation of apparently presynaptic NMDA receptors. These LTP and LTD mechanisms detected firing coincidence on ~25 and ~125 ms time scales, respectively, and combined to implement the overall STDP rule. These findings indicate that STDP is not a unitary process and suggest that endocannabinoid-dependent LTD may be relevant to cortical map plasticity. PMID:16624937

Conical Shock-Strength Determination on a Low-Sonic-Boom Aircraft Model by Doppler Global Velocimetry

NASA Technical Reports Server (NTRS)

Herring, Gregory C.; Meyers, James F.

2011-01-01

A nonintrusive technique Doppler global velocimetry (DGV) was used to determine conical shock strengths on a supersonic-cruise low-boom aircraft model. The work was performed at approximately Mach 2 in the Unitary Plan Wind Tunnel. Water is added to the wind tunnel flow circuit, generating small ice particles used as seed particles for the laser-based velocimetry. DGV generates two-dimensional (2-D) maps of three components of velocity that span the oblique shock. Shock strength (i.e. fractional pressure increase) is determined from observation of the flow deflection angle across the shock in combination with the standard shock relations. Although DGV had conveniently and accurately determined shock strengths from the homogenous velocity fields behind 2-D planar shocks, the inhomogeneous 3-D velocity fields behind the conical shocks presented additional challenges. Shock strength measurements for the near-field conical nose shock were demonstrated and compared with previously-published static pressure probe data for the same model in the same wind tunnel. Fair agreement was found between the two sets of results.

Wavefront shaping to correct intraocular scattering

NASA Astrophysics Data System (ADS)

Artal, Pablo; Arias, Augusto; Fernández, Enrique

2018-02-01

Cataracts is a common ocular pathology that increases the amount of intraocular scattering. It degrades the quality of vision by both blur and contrast reduction of the retinal images. In this work, we propose a non-invasive method, based on wavefront shaping (WS), to minimize cataract effects. For the experimental demonstration of the method, a liquid crystal on silicon (LCoS) spatial light modulator was used for both reproduction and reduction of the realistic cataracts effects. The LCoS area was separated in two halves conjugated with the eye's pupil by a telescope with unitary magnification. Thus, while the phase maps that induced programmable amounts of intraocular scattering (related to cataract severity) were displayed in a one half of the LCoS, sequentially testing wavefronts were displayed in the second one. Results of the imaging improvements were visually evaluated by subjects with no known ocular pathology seeing through the instrument. The diffracted intensity of exit pupil is analyzed for the feedback of the implemented algorithms in search for the optimum wavefront. Numerical and experimental results of the imaging improvements are presented and discussed.

A Protocol for Advanced Psychometric Assessment of Surveys

PubMed Central

Squires, Janet E.; Hayduk, Leslie; Hutchinson, Alison M.; Cranley, Lisa A.; Gierl, Mark; Cummings, Greta G.; Norton, Peter G.; Estabrooks, Carole A.

2013-01-01

Background and Purpose. In this paper, we present a protocol for advanced psychometric assessments of surveys based on the Standards for Educational and Psychological Testing. We use the Alberta Context Tool (ACT) as an exemplar survey to which this protocol can be applied. Methods. Data mapping, acceptability, reliability, and validity are addressed. Acceptability is assessed with missing data frequencies and the time required to complete the survey. Reliability is assessed with internal consistency coefficients and information functions. A unitary approach to validity consisting of accumulating evidence based on instrument content, response processes, internal structure, and relations to other variables is taken. We also address assessing performance of survey data when aggregated to higher levels (e.g., nursing unit). Discussion. In this paper we present a protocol for advanced psychometric assessment of survey data using the Alberta Context Tool (ACT) as an exemplar survey; application of the protocol to the ACT survey is underway. Psychometric assessment of any survey is essential to obtaining reliable and valid research findings. This protocol can be adapted for use with any nursing survey. PMID:23401759

The inhibitory microcircuit of the substantia nigra provides feedback gain control of the basal ganglia output.

PubMed

Brown, Jennifer; Pan, Wei-Xing; Dudman, Joshua Tate

2014-05-21

Dysfunction of the basal ganglia produces severe deficits in the timing, initiation, and vigor of movement. These diverse impairments suggest a control system gone awry. In engineered systems, feedback is critical for control. By contrast, models of the basal ganglia highlight feedforward circuitry and ignore intrinsic feedback circuits. In this study, we show that feedback via axon collaterals of substantia nigra projection neurons control the gain of the basal ganglia output. Through a combination of physiology, optogenetics, anatomy, and circuit mapping, we elaborate a general circuit mechanism for gain control in a microcircuit lacking interneurons. Our data suggest that diverse tonic firing rates, weak unitary connections and a spatially diffuse collateral circuit with distinct topography and kinetics from feedforward input is sufficient to implement divisive feedback inhibition. The importance of feedback for engineered systems implies that the intranigral microcircuit, despite its absence from canonical models, could be essential to basal ganglia function. DOI: http://dx.doi.org/10.7554/eLife.02397.001. Copyright © 2014, Brown et al.

Mapping the Braiding Properties of Non-Abelian FQHE Liquids.

NASA Astrophysics Data System (ADS)

Prodan, Emil; Haldane, F. D. M.

2007-03-01

Non-Abelian FQHE (NAFQHE) states have elementary excitations that cannot be individually locally-created. When widely separated, they give rise to topological (quasi-)degeneracy of the quantum states; braiding of such non-Abelian quasiparticles (NAQP's) implements unitary transformations among the degenerate states that may be useful for ``topological quantum computing'' (TQC). We have developed a new technique for explicit computation of NAQP braiding in models exhibiting ideal NAFQHE behavior (where the topological degeneracy is exact), in particular the Moore-Read ν = 5/2 state. For systems of small numbers of NAQP's on a sphere, we have computed the non-Abelian Berry curvature and Hilbert space metric, as one NAQP is moved relative to a fixed configuration of the others, showing how the topological properties develop as the system size (NAQP separation) increases. We also studied the effect of perturbations (Coulomb interaction and substrate potentials) that lift the exact degeneracy, and become the dominant corrections when NAQP's are brought together so that quantum measurements can be made; these effects are likely to be crucial in determining whether TQC is viable in NAFQHE systems.

Communicating infectious disease prevalence through graphics: Results from an international survey.

PubMed

Fagerlin, Angela; Valley, Thomas S; Scherer, Aaron M; Knaus, Megan; Das, Enny; Zikmund-Fisher, Brian J

2017-07-13

Graphics are increasingly used to represent the spread of infectious diseases (e.g., influenza, Zika, Ebola); however, the impact of using graphics to adequately inform the general population is unknown. To examine whether three ways of visually presenting data (heat map, dot map, or picto-trendline)-all depicting the same information regarding the spread of a hypothetical outbreak of influenza-influence intent to vaccinate, risk perception, and knowledge. Survey with participants randomized to receive a simulated news article accompanied by one of the three graphics that communicated prevalence of influenza and number of influenza-related deaths. International online survey. 16,510 adults living in 11 countries selected using stratified random sampling based on age and gender. After reading the article and viewing the presented graphic, participants completed a survey that measured interest in vaccination, perceived risk of contracting disease, knowledge gained, interest in additional information about the disease, and perception of the graphic. Heat maps and picto-trendlines were evaluated more positively than dot maps. Heat maps were more effective than picto-trendlines and no different from dot maps at increasing interest in vaccination, perceived risk of contracting disease, and interest in additional information about the disease. Heat maps and picto-trendlines were more successful at conveying knowledge than dot maps. Overall, heat maps were the only graphic to be superior in every outcome. Results are based on a hypothetical scenario. Heat maps are a viable option to promote interest in and concern about infectious diseases. Published by Elsevier Ltd.

Stability of the Zagreb realization of the Carnegie-Mellon-Berkeley coupled-channels unitary model

NASA Astrophysics Data System (ADS)

Osmanović, H.; Ceci, S.; Švarc, A.; Hadžimehmedović, M.; Stahov, J.

2011-09-01

In Hadžimehmedović [Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.84.035204 84, 035204 (2011)] we have used the Zagreb realization of Carnegie-Melon-Berkeley coupled-channel, unitary model as a tool for extracting pole positions from the world collection of partial-wave data, with the aim of eliminating model dependence in pole-search procedures. In order that the method is sensible, we in this paper discuss the stability of the method with respect to the strong variation of different model ingredients. We show that the Zagreb CMB procedure is very stable with strong variation of the model assumptions and that it can reliably predict the pole positions of the fitted partial-wave amplitudes.

Wave functions of the Q .Q interaction in terms of unitary 9-j coefficients

NASA Astrophysics Data System (ADS)

Zamick, Larry; Harper, Matthew

2015-03-01

We obtain wave functions for two protons and two neutrons in the g9 /2 shell expressed as column vectors with amplitudes D (Jp,Jn) . When we use a quadrupole-quadrupole interaction (Q .Q ) we get, in many cases, a very strong overlap with wave functions given by a single set of unitary 9-j coefficients—U 9 j =<(jj ) 2 j(jjJB|(jj ) Jp(jj ) Jn) I> . Here JB=9 for even I T =0 states. For both even and odd T =1 states we take JB equal to 8 whilst for odd I ,T =0 we take JB to be 7. We compare the Q .Q results with those of a more realistic interaction.

Multi-Hop Teleportation of an Unknown Qubit State Based on W States

NASA Astrophysics Data System (ADS)

Zhou, Xiang-Zhen; Yu, Xu-Tao; Zhang, Zai-Chen

2018-04-01

Quantum teleportation is important in quantum communication networks. Considering that quantum state information is also transmitted between two distant nodes, intermediated nodes are employed and two multi-hop teleportation protocols based on W state are proposed. One is hop-by-hop teleportation protocol and the other is the improved multi-hop teleportation protocol with centralized unitary transformation. In hop-by-hop protocol, the transmitted quantum state needs to be recovered at every node on the route. In improved multi-hop teleportation protocol with centralized unitary transformation, intermediate nodes need not to recover the transmitted quantum state. Compared to the hop-by-hop protocol, the improved protocol can reduce the transmission delay and improve the transmission efficiency.

Practical Unitary Simulator for Non-Markovian Complex Processes

NASA Astrophysics Data System (ADS)

Binder, Felix C.; Thompson, Jayne; Gu, Mile

2018-06-01

Stochastic processes are as ubiquitous throughout the quantitative sciences as they are notorious for being difficult to simulate and predict. In this Letter, we propose a unitary quantum simulator for discrete-time stochastic processes which requires less internal memory than any classical analogue throughout the simulation. The simulator's internal memory requirements equal those of the best previous quantum models. However, in contrast to previous models, it only requires a (small) finite-dimensional Hilbert space. Moreover, since the simulator operates unitarily throughout, it avoids any unnecessary information loss. We provide a stepwise construction for simulators for a large class of stochastic processes hence directly opening the possibility for experimental implementations with current platforms for quantum computation. The results are illustrated for an example process.

Design for a Unitary Graphite Composite Instrument Boom

NASA Technical Reports Server (NTRS)

Alexander, Wes; Carlos, Rene; Sturm, James; Rossoni, Peter

2004-01-01

This paper describes development of a Unitary graphite composite instrument boom that incorporates carpenter-tape like hinges for stowage. While light and stiff, graphite composite is not ordinarily thought of as a flexible material. This design has taken advantage of the stiffness of the composite in tubular geometry, yet leveraged its thin- section behavior to place flexibility at the required locations. Key is the proprietary layup, which results in a tough yet flexible hinge capable of rotating over 90 degrees in each direction. When the boom deploys, there is enough torque to overcome parasitic resistance from harness, etc. It will snap to the fully extended, rigid shape. The design has addressed materials issues such as out-of-plane bending, edge cracking, and interlaminar ply separation.

Unitary limit of two-nucleon interactions in strong magnetic fields

DOE PAGES

Detmold, William; Orginos, Kostas; Parreño, Assumpta; ...

2016-03-14

In this study, two-nucleon systems are shown to exhibit large scattering lengths in strong magnetic fields at unphysical quark masses, and the trends toward the physical values indicate that such features may exist in nature. Lattice QCD calculations of the energies of one and two nucleons systems are performed at pion masses of m π ~ 450 and 806 MeV in uniform, time-independent magnetic fields of strength |B| ~ 10 19 – 10 20 Gauss to determine the response of these hadronic systems to large magnetic fields. Fields of this strength may exist inside magnetars and in peripheral relativistic heavymore » ion collisions, and the unitary behavior at large scattering lengths may have important consequences for these systems.« less

Vapor-screen technique for flow visualization in the Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Morris, O. A.; Corlett, W. A.; Wassum, D. L.; Babb, C. D.

1985-01-01

The vapor-screen technique for flow visualization, as developed for the Langley Unitary Plan Wind Tunnel, is described with evaluations of light sources and photographic equipment. Test parameters including dew point, pressure, and temperature were varied to determine optimum conditions for obtaining high-quality vapor-screen photographs. The investigation was conducted in the supersonic speed range for Mach numbers from 1.47 to 4.63 at model angles of attack up to 35 deg. Vapor-screen photographs illustrating various flow patterns are presented for several missile and aircraft configurations. Examples of vapor-screen results that have contributed to the understanding of complex flow fields and provided a basis for the development of theoretical codes are presented with reference to other research.

Effect of Map-vaccination in ewes on body condition score, weight and Map-shedding.

PubMed

Hüttner, Klim; Krämer, Ulla; Kleist, Petra

2012-01-01

Vaccination against Mycobacterium avium subspecies paratuberculosis (Map) in sheep receives growing attention worldwide, particularly in countries with national Map control strategies. A field study was conducted, investigating the effect of GUDAIR on body condition, weight and Map-shedding in a professionally managed but largely Map-affected suffolk flock prior and after vaccination. For this, 80 ewes out of 1000 animals were randomly sampled. In the univariate analysis body condition scores of ewes twelve months after vaccination improved significantly compared to those sampled prior to vaccination. At the same time the rate of ewes shedding Map was reduced by 37%.

The use of crop rotation for mapping soil organic content in farmland

NASA Astrophysics Data System (ADS)

Yang, Lin; Song, Min; Zhu, A.-Xing; Qin, Chengzhi

2017-04-01

Most of the current digital soil mapping uses natural environmental covariates. However, human activities have significantly impacted the development of soil properties since half a century, and therefore become an important factor affecting soil spatial variability. Many researches have done field experiments to show how soil properties are impacted and changed by human activities, however, spatial variation data of human activities as environmental covariates have been rarely used in digital soil mapping. In this paper, we took crop rotation as an example of agricultural activities, and explored its effectiveness in characterizing and mapping the spatial variability of soil. The cultivated area of Xuanzhou city and Langxi County in Anhui Province was chosen as the study area. Three main crop rotations,including double-rice, wheat-rice,and oilseed rape-cotton were observed through field investigation in 2010. The spatial distribution of the three crop rotations in the study area was obtained by multi-phase remote sensing image interpretation using a supervised classification method. One-way analysis of variance (ANOVA) for topsoil organic content in the three crop rotation groups was performed. Factor importance of seven natural environmental covariates, crop rotation, Land use and NDVI were generated by variable importance criterion of Random Forest. Different combinations of environmental covariates were selected according to the importance rankings of environmental covariates for predicting SOC using Random Forest and Soil Landscape Inference Model (SOLIM). A cross validation was generated to evaluated the mapping accuracies. The results showed that there were siginificant differences of topsoil organic content among the three crop rotation groups. The crop rotation is more important than parent material, land use or NDVI according to the importance ranking calculated by Random Forest. In addition, crop rotation improved the mapping accuracy, especially for the flat clutivated area. This study demonstrates the usefulness of human activities in digital soil mapping and thus indicates the necessity for human activity factors in digital soil mapping studies.

Mapping forest vegetation for the western United States using modified random forests imputation of FIA forest plots

Treesearch

Karin Riley; Isaac C. Grenfell; Mark A. Finney

2016-01-01

Maps of the number, size, and species of trees in forests across the western United States are desirable for many applications such as estimating terrestrial carbon resources, predicting tree mortality following wildfires, and for forest inventory. However, detailed mapping of trees for large areas is not feasible with current technologies, but statistical...

The Effects of Concept Mapping and Academic Self-Efficacy on Mastery Goals and Reading Comprehension Achievement

ERIC Educational Resources Information Center

Wilson, Andrew; Kim, Wonsun

2016-01-01

The purpose of the study is to investigate the effects of concept mapping on mastery goal orientation and academic self-efficacy in a collaborative learning environment. The current study employed a randomized controlled pretest-posttest group design to examine if learning strategies such as concept mapping can help students with both reading…

PSO algorithm enhanced with Lozi Chaotic Map - Tuning experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pluhacek, Michal; Senkerik, Roman; Zelinka, Ivan

2015-03-10

In this paper it is investigated the effect of tuning of control parameters of the Lozi Chaotic Map employed as a chaotic pseudo-random number generator for the particle swarm optimization algorithm. Three different benchmark functions are selected from the IEEE CEC 2013 competition benchmark set. The Lozi map is extensively tuned and the performance of PSO is evaluated.

Improved diagonal queue medical image steganography using Chaos theory, LFSR, and Rabin cryptosystem.

PubMed

Jain, Mamta; Kumar, Anil; Choudhary, Rishabh Charan

2017-06-01

In this article, we have proposed an improved diagonal queue medical image steganography for patient secret medical data transmission using chaotic standard map, linear feedback shift register, and Rabin cryptosystem, for improvement of previous technique (Jain and Lenka in Springer Brain Inform 3:39-51, 2016). The proposed algorithm comprises four stages, generation of pseudo-random sequences (pseudo-random sequences are generated by linear feedback shift register and standard chaotic map), permutation and XORing using pseudo-random sequences, encryption using Rabin cryptosystem, and steganography using the improved diagonal queues. Security analysis has been carried out. Performance analysis is observed using MSE, PSNR, maximum embedding capacity, as well as by histogram analysis between various Brain disease stego and cover images.