10,908 research outputs found
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Kleshchev's decomposition numbers and branching coefficients in the Fock space
10.1090/S0002-9947-07-04202-XTransactions of the American Mathematical Society36031179-119
High Dynamic Range RF Front End with Noise Cancellation and Linearization for WiMAX Receivers
This research deals with verification of the high dynamic range for a heterodyne radio frequency (RF) front end. A 2.6 GHz RF front end is designed and implemented in a hybrid microwave integrated circuit (HMIC) for worldwide interoperability for microwave access (WiMAX) receivers. The heterodyne RF front end consists of a low-noise amplifier (LNA) with noise cancellation, an RF bandpass filter (BPF), a downconverter with linearization, and an intermediate frequency (IF) BPF. A noise canceling technique used in the low-noise amplifier eliminates a thermal noise and then reduces the noise figure (NF) of the RF front end by 0.9 dB. Use of a downconverter with diode linearizer also compensates for gain compression, which increases the input-referred third-order intercept point (IIP3) of the RF front end by 4.3 dB. The proposed method substantially increases the spurious-free dynamic range (DRf) of the RF front end by 3.5 dB
Property testing of unitary operators
In this paper, we systematically study property testing of unitary operators.
We first introduce a distance measure that reflects the average difference
between unitary operators. Then we show that, with respect to this distance
measure, the orthogonal group, quantum juntas (i.e. unitary operators that only
nontrivially act on a few qubits of the system) and Clifford group can be all
efficiently tested. In fact, their testing algorithms have query complexities
independent of the system's size and have only one-sided error. Then we give an
algorithm that tests any finite subset of the unitary group, and demonstrate an
application of this algorithm to the permutation group. This algorithm also has
one-sided error and polynomial query complexity, but it is unknown whether it
can be efficiently implemented in general
Parallelotope tilings and q-decomposition numbers
We provide closed formulas for a large subset of the canonical basis vectors of the Fock space representation of Uq(slₑ). These formulas arise from parallelotopes which assemble to form polytopal complexes. The subgraphs of the Ext¹ -quivers of v-Schur algebras at complex e-th roots of unity generated by simple modules corresponding to these canonical basis vectors are given by the 1-skeletons of the polytopal complexes
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A v-analogue of Peel's theorem
We compute the v-decomposition numbers dλμ(v) for λ being a hook partition, and μ e-regular
Implementation of a three-quantum-bit search algorithm
We report the experimental implementation of Grover's quantum search
algorithm on a quantum computer with three quantum bits. The computer consists
of molecules of C-labeled CHFBr, in which the three weakly coupled
spin-1/2 nuclei behave as the bits and are initialized, manipulated, and read
out using magnetic resonance techniques. This quantum computation is made
possible by the introduction of two techniques which significantly reduce the
complexity of the experiment and by the surprising degree of cancellation of
systematic errors which have previously limited the total possible number of
quantum gates.Comment: Published in Applied Physics Letters, vol. 76, no. 5, 31 January
2000, p.646-648, after minor revisions. (revtex, mypsfig2.sty, 3 figures
Ground-state configuration space heterogeneity of random finite-connectivity spin glasses and random constraint satisfaction problems
We demonstrate through two case studies, one on the p-spin interaction model
and the other on the random K-satisfiability problem, that a heterogeneity
transition occurs to the ground-state configuration space of a random
finite-connectivity spin glass system at certain critical value of the
constraint density. At the transition point, exponentially many configuration
communities emerge from the ground-state configuration space, making the
entropy density s(q) of configuration-pairs a non-concave function of
configuration-pair overlap q. Each configuration community is a collection of
relatively similar configurations and it forms a stable thermodynamic phase in
the presence of a suitable external field. We calculate s(q) by the
replica-symmetric and the first-step replica-symmetry-broken cavity methods,
and show by simulations that the configuration space heterogeneity leads to
dynamical heterogeneity of particle diffusion processes because of the entropic
trapping effect of configuration communities. This work clarifies the fine
structure of the ground-state configuration space of random spin glass models,
it also sheds light on the glassy behavior of hard-sphere colloidal systems at
relatively high particle volume fraction.Comment: 26 pages, 9 figures, submitted to Journal of Statistical Mechanic
A Numerical Simulator for Three-Dimensional Flows Through Vibrating Blade Rows
The three-dimensional, multi-stage, unsteady, turbomachinery analysis, TURBO, has been extended to predict the aeroelastic and aeroacoustic response behaviors of a single blade row operating within a cylindrical annular duct. In particular, a blade vibration capability has been incorporated so that the TURBO analysis can be applied over a solution domain that deforms with a vibratory blade motion. Also, unsteady far-field conditions have been implemented to render the computational boundaries at inlet and exit transparent to outgoing unsteady disturbances. The modified TURBO analysis is applied herein to predict unsteady subsonic and transonic flows. The intent is to partially validate this nonlinear analysis for blade flutter applications, via numerical results for benchmark unsteady flows, and to demonstrate the analysis for a realistic fan rotor. For these purposes, we have considered unsteady subsonic flows through a 3D version of the 10th Standard Cascade, and unsteady transonic flows through the first stage rotor of the NASA Lewis, Rotor 67, two-stage fan
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