57,285 research outputs found

    The spectrum of the S^5 compactification of the chiral N=2, D=10 supergravity and the unitary supermultiplets of U(2,2/4)

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    The authors calculate the spectrum of the S^5 compactification of the chiral N=2, D=10 supergravity theory. The modes on S^5 fall into unitary irreducible representations of the D=5, N=8 anti-de Sitter supergroup U(2,2/4). These unitary supermultiplets involve field of spin <or=2 with quantised 'mass' eigenvalues. The massless multiplet contains fifteen vector fields, six self-dual and six anti-self-dual anti-symmetric tensor fields. The fields of the massless multiplet are expected to be those of a gauged N=8 theory in D=5 with a local gauge group SU(4)

    Bluetooth low energy for autonomous human-robot interaction

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    © 2017 Copyright held by the owner/author(s).This demonstration shows how inexpensive, off-the-shelf, and unobtrusive Bluetooth Low Energy (BLE) devices can be utilized for enabling robots to recognize touch gestures, to perceive proximity information, and to distinguish between interacting individuals autonomously. The received signal strength (RSS) between the BLE device attached to the robot and BLE devices attached to the interacting individuals is used to achieve this. Almost no software configuration is needed and the setup can be applied to most everyday environments and robot platforms

    Cluster algebras in scattering amplitudes with special 2D kinematics

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    We study the cluster algebra of the kinematic configuration space Confn(P3)Conf_n(\mathbb{P}^3) of a n-particle scattering amplitude restricted to the special 2D kinematics. We found that the n-points two loop MHV remainder function found in special 2D kinematics depend on a selection of \XX-coordinates that are part of a special structure of the cluster algebra related to snake triangulations of polygons. This structure forms a necklace of hypercubes beads in the corresponding Stasheff polytope. Furthermore in n=12n = 12, the cluster algebra and the selection of \XX-coordinates in special 2D kinematics replicates the cluster algebra and the selection of \XX-coordinates of n=6n=6 two loop MHV amplitude in 4D kinematics.Comment: 22 page

    Snake States in Graphene p-n Junctions

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    We investigate transport in locally-gated graphene devices, where carriers are injected and collected along, rather than across, the gate edge. Tuning densities into the p-n regime significantly reduces resistance along the p-n interface, while resistance across the interface increases. This provides an experimental signature of snake states, which zig-zag along the p-n interface and remain stable as applied perpendicular magnetic field approaches zero. Snake states appear as a peak in transverse resistance measured along the p-n interface. The generic role of snake states disordered graphene is also discussed.Comment: supplemental material available at http://marcuslab.harvard.edu/papers/Williams_SnakesSupp.pd

    Collisional broadening and spectral line shape of an entire rotational band

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    The impact approximation is applied to the classical binary collision operator making it possible to derive an expression for the dipole correlation function for real systems in a form which is computationally tractable and contains no adjustable parameters. Trajectory calculations are performed (in order to evaluate the microscopic expression for the relaxation parameter in the correlation function) for the system CO in dense Ar gas. Comparison is made with experimental data and excellent agreement is found for certain densities when a quantum correction is included. At higher densities (i.e., ρ^(−1/3)< "the range of the potential") one approximation is not valid and comparison with experiment illustrates this point

    Regulation of tissue crosstalk by skeletal muscle-derived myonectin and other myokines.

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    The integrated control of animal physiology requires intimate tissue crosstalk, a vital task mediated by circulating humoral factors. As one type of these factors, adipose tissue-derived adipokines have recently garnered attention as important regulators of systemic insulin sensitivity and metabolic homeostasis. However, the realization that skeletal muscle also secretes a variety of biologically and metabolically active polypeptide factors (collectively called myokines) has provided a new conceptual framework to understand the critical role skeletal muscle plays in coordinating whole-body energy balance. Here, we highlight recent progress made in the myokine field and discuss possible roles of myonectin, which we have recently identified as a potential postprandial signal derived from skeletal muscle to integrate metabolic processes in other tissues, such as adipose and liver; one of its roles is to promote fatty acid uptake into cells. Myonectin is also likely an important mediator in inter-tissue crosstalk

    The role of vibrational–rotational coupling in V–V and V–R,T energy transfer

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    The effect of neglecting vibrational–rotational coupling in energy transfer calculations is studied for collisions of HF (v=1–7) with HF (v=0). An analog of a "classical path" method is considered in which rigid-rotor trajectories are used to determine a time-dependent forcing term on the vibrational motion of each molecule. The results are compared with our quasiclassical calculations in which no such approximation was used. At higher vibrational states the rigid-rotor forced-oscillator model is found to predict substantially smaller V–R,T rate constants than those found in the exact study

    Bound states in the one-dimensional two-particle Hubbard model with an impurity

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    We investigate bound states in the one-dimensional two-particle Bose-Hubbard model with an attractive (V>0V> 0) impurity potential. This is a one-dimensional, discrete analogy of the hydrogen negative ion H^- problem. There are several different types of bound states in this system, each of which appears in a specific region. For given VV, there exists a (positive) critical value Uc1U_{c1} of UU, below which the ground state is a bound state. Interestingly, close to the critical value (UUc1U\lesssim U_{c1}), the ground state can be described by the Chandrasekhar-type variational wave function, which was initially proposed for H^-. For U>Uc1U>U_{c1}, the ground state is no longer a bound state. However, there exists a second (larger) critical value Uc2U_{c2} of UU, above which a molecule-type bound state is established and stabilized by the repulsion. We have also tried to solve for the eigenstates of the model using the Bethe ansatz. The model possesses a global \Zz_2-symmetry (parity) which allows classification of all eigenstates into even and odd ones. It is found that all states with odd-parity have the Bethe form, but none of the states in the even-parity sector. This allows us to identify analytically two odd-parity bound states, which appear in the parameter regions 2V<U<V-2V<U<-V and V<U<0-V<U<0, respectively. Remarkably, the latter one can be \textit{embedded} in the continuum spectrum with appropriate parameters. Moreover, in part of these regions, there exists an even-parity bound state accompanying the corresponding odd-parity bound state with almost the same energy.Comment: 18 pages, 18 figure
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