36,809 research outputs found
Opportunistic Relaying in Time Division Broadcast Protocol with Incremental Relaying
In this paper, we investigate the performance of time division broadcast protocol (TDBC) with incremental relaying (IR) when there are multiple available relays. Opportunistic relaying (OR), i.e., the “best” relay is select for transmission to minimize the system’s outage probability, is proposed. Two OR schemes are presented. The first scheme, termed TDBC-OIR-I, selects the “best” relay from the set of relays that can decode both flows of signal from the two sources successfully. The second one, termed TDBC-OIR-II, selects two “best” relays from two respective sets of relays that can decode successfully each flow of signal. The performance, in terms of outage probability, expected rate (ER), and diversity-multiplexing tradeoff (DMT), of the two schemes are analyzed and compared with two TDBC schemes that have no IR but OR (termed TDBC-OR-I and TDBC-OR-II accordingly) and two other benchmark OR schemes that have no direct link transmission between the two sources
High-pressure study of the basal-plane anisotropy of the upper critical field of the topological superconductor SrxBi2Se3
We report a high-pressure transport study of the upper-critical field,
, of the topological superconductor SrBiSe ( K). was measured for magnetic fields directed along two
orthogonal directions, and , in the trigonal basal plane. While
superconductivity is rapidly suppressed at the critical pressure
GPa, the pronounced two-fold basal-plane anisotropy at K, recently reported at ambient pressure (Pan et al., 2016), is
reinforced and attains a value of at the highest pressure (2.2 GPa).
The data reveal that the unconventional superconducting state with broken
rotational symmetry is robust under pressure
Superconductivity and magnetic order in the non-centrosymmetric Half Heusler compound ErPdBi
We report superconductivity at K and magnetic order at K in the semi-metallic noncentrosymmetric Half Heusler compound ErPdBi.
The upper critical field, , has an unusual quasi-linear temperature
variation and reaches a value of 1.6 T for . Magnetic order is
found below and is suppressed at T for . Since , the interaction of superconductivity and magnetism
is expected to give rise to a complex ground state. Moreover, electronic
structure calculations show ErPdBi has a topologically nontrivial band
inversion and thus may serve as a new platform to study the interplay of
topological states, superconductivity and magnetic order.Comment: 6 pages, 5 figures; accepted for publication in Europhysics Letter
Chimera order in spin systems
Homogeneous populations of oscillators have recently been shown to exhibit
stable coexistence of coherent and incoherent regions. Generalizing the concept
of chimera states to the context of order-disorder transition in systems at
thermal equilibrium, we show analytically that such complex ordering can appear
in a system of Ising spins, possibly the simplest physical system exhibiting
this phenomenon. We also show numerically the existence of chimera ordering in
3-dimensional spin systems that model layered magnetic materials, suggesting
possible means of experimentally observing such states.Comment: 5 pages, 3 figure
Josephson scanning tunneling microscopy
We propose a set of scanning tunneling microscopy experiments in which the
surface of superconductor is scanned by a superconducting tip. Potential
capabilities of such experimental setup are discussed. Most important
anticipated results of such an experiment include the position-resolved
measurement of the superconducting order parameter and the possibility to
determine the nature of the secondary component of the order parameter at the
surface. The theoretical description based on the tunneling Hamiltonian
formalism is presented.Comment: 6 pages, 7 figures, submitted to Phys. Rev.
An improved generalization of mesh-connected computers with multiple buses
©2001 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Mesh-connected computers (MCCs) are a class of important parallel architectures due to their simple and regular interconnections. However, their performances are restricted by their large diameters. Various augmenting mechanisms have been proposed to enhance the communication efficiency of MCCs. One major approach is to add nonconfigurable buses for improved broadcasting. A typical example is the mesh-connected computer with multiple buses (MMB). We propose a new class of generalized MMBs, the improved generalized MMBs (IMMBs). We compare IMMBs with MMBs and a class of previously proposed generalized MMBs (GMMBs). We show the power of IMMBs by considering semigroup and prefix computations. Specifically, as our main result we show that for any constant 0<ϵ<1, one can construct an N½×N½ square IMMB using which semigroup and prefix computations on N operands can be carried out in O(Nϵ) time, while maintaining O(1) broadcasting time. Compared with the previous best complexities O(N⅛) and O(N&frac116;) achieved on a rectangular MMB and GMMB, respectively, for the same computations, our results show that IMMBs are more powerful than MMBs and GMMBsYi Pen; Zheng, S.Q.; Keqin Li; Hong She
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