The Experts below are selected from a list of 52242 Experts worldwide ranked by ideXlab platform
S. Attallah - One of the best experts on this subject based on the ideXlab platform.
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VTC Spring - Speeding up Noise Subspace Estimation Algorithms using an Optimal Diagonal Matrix Step-Size Strategy for MC-CDMA Application
VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008Co-Authors: Lu Yang, S. AttallahAbstract:In this paper, we propose a new optimal Diagonal-Matrix step-size strategy for some noise subspace estimation algorithms. The proposed step-sizes control the decoupled subspace vectors individually as compared to conventional methods where all the subspace vectors are multiplied by the same step-size value. Simulation results show that this optimal Diagonal- Matrix step-size strategy outperforms the original algorithms as it offers faster convergence rate, smaller steady state error and similar orthogonality error simultaneously. Finally, the algorithms with the proposed step-size strategy are used for blind channel estimation in MC-CDMA system.
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SiPS - Adaptive Noise Subspace Estimation Algorithm with an Optimal Diagonal-Matrix Step-Size
2007 IEEE Workshop on Signal Processing Systems, 2007Co-Authors: Lu Yang, S. AttallahAbstract:In this paper, we propose a new optimal Diagonal-Matrix step-size for the fast data projection method (FDPM) algorithm. The proposed step-sizes control the decoupled subspace vectors individually as compared to conventional methods where all the subspace vectors are multiplied by the same step-size value (scalar case). Simulation results show that FDPM with this optimal Diagonal-Matrix step-size outperforms the original algorithm as it offers faster convergence rate, smaller steady state error and smaller orthogonality error simultaneously. The proposed method can easily be applied to other subspace algorithms as well.
Marcos Rigol - One of the best experts on this subject based on the ideXlab platform.
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Low-frequency behavior of off-Diagonal Matrix elements in the integrable XXZ chain and in a locally perturbed quantum-chaotic XXZ chain
Physical Review B, 2020Co-Authors: Marlon Brenes, John Goold, Marcos RigolAbstract:We study the Matrix elements of local operators in the eigenstates of the integrable XXZ chain and of the quantum-chaotic model obtained by locally perturbing the XXZ chain with a magnetic impurity. We show that, at frequencies that are polynomially small in the system size, the behavior of the variances of the off-Diagonal Matrix elements can be starkly different depending on the operator. In the integrable model we find that, as the frequency $\omega\rightarrow0$, the variances are either nonvanishing (generic behavior) or vanishing (for a special class of operators). In the quantum-chaotic model, on the other hand, we find the variances to be nonvanishing as $\omega\rightarrow0$ and to indicate diffusive dynamics. We highlight which properties of the Matrix elements of local operators are different between the integrable and quantum-chaotic models independently of the specific operator selected.
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eigenstate thermalization in the two dimensional transverse field ising model ii off Diagonal Matrix elements of observables
Physical Review E, 2017Co-Authors: Rubem Mondaini, Marcos RigolAbstract:: We study the Matrix elements of few-body observables, focusing on the off-Diagonal ones, in the eigenstates of the two-dimensional transverse field Ising model. By resolving all symmetries, we relate the onset of quantum chaos to the structure of the Matrix elements. In particular, we show that a general result of the theory of random matrices, namely, the value 2 of the ratio of variances (Diagonal to off-Diagonal) of the Matrix elements of Hermitian operators, occurs in the quantum chaotic regime. Furthermore, we explore the behavior of the off-Diagonal Matrix elements of observables as a function of the eigenstate energy differences and show that it is in accordance with the eigenstate thermalization hypothesis ansatz.
G Wunner - One of the best experts on this subject based on the ideXlab platform.
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SEMICLASSICAL SPECTRA AND Diagonal Matrix ELEMENTS BY HARMONIC INVERSION OF CROSS-CORRELATED PERIODIC ORBIT SUMS
Physical Review E, 1999Co-Authors: J Main, K Weibert, V A Mandelshtam, G WunnerAbstract:Semiclassical spectra weighted with products of Diagonal Matrix elements of operators A(alpha), i.e., g(alphaalpha')(E)= summation operator(n) /(E-E(n)), are obtained by harmonic inversion of a cross-correlation signal constructed of classical periodic orbits. The method provides highly resolved semiclassical spectra even in situations of nearly degenerate states, and opens the way to reducing the required signal lengths to shorter than the Heisenberg time. This implies a significant reduction of the number of orbits required for periodic orbit quantization by harmonic inversion.
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Semiclassical spectra and Diagonal Matrix elements by harmonic inversion of cross-correlated periodic orbit sums.
Physical review. E Statistical physics plasmas fluids and related interdisciplinary topics, 1999Co-Authors: J Main, K Weibert, V A Mandelshtam, G WunnerAbstract:Semiclassical spectra weighted with products of Diagonal Matrix elements of operators A(alpha), i.e., g(alphaalpha')(E)= summation operator(n)
Lu Yang - One of the best experts on this subject based on the ideXlab platform.
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VTC Spring - Speeding up Noise Subspace Estimation Algorithms using an Optimal Diagonal Matrix Step-Size Strategy for MC-CDMA Application
VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008Co-Authors: Lu Yang, S. AttallahAbstract:In this paper, we propose a new optimal Diagonal-Matrix step-size strategy for some noise subspace estimation algorithms. The proposed step-sizes control the decoupled subspace vectors individually as compared to conventional methods where all the subspace vectors are multiplied by the same step-size value. Simulation results show that this optimal Diagonal- Matrix step-size strategy outperforms the original algorithms as it offers faster convergence rate, smaller steady state error and similar orthogonality error simultaneously. Finally, the algorithms with the proposed step-size strategy are used for blind channel estimation in MC-CDMA system.
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SiPS - Adaptive Noise Subspace Estimation Algorithm with an Optimal Diagonal-Matrix Step-Size
2007 IEEE Workshop on Signal Processing Systems, 2007Co-Authors: Lu Yang, S. AttallahAbstract:In this paper, we propose a new optimal Diagonal-Matrix step-size for the fast data projection method (FDPM) algorithm. The proposed step-sizes control the decoupled subspace vectors individually as compared to conventional methods where all the subspace vectors are multiplied by the same step-size value (scalar case). Simulation results show that FDPM with this optimal Diagonal-Matrix step-size outperforms the original algorithm as it offers faster convergence rate, smaller steady state error and smaller orthogonality error simultaneously. The proposed method can easily be applied to other subspace algorithms as well.
J Main - One of the best experts on this subject based on the ideXlab platform.
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SEMICLASSICAL SPECTRA AND Diagonal Matrix ELEMENTS BY HARMONIC INVERSION OF CROSS-CORRELATED PERIODIC ORBIT SUMS
Physical Review E, 1999Co-Authors: J Main, K Weibert, V A Mandelshtam, G WunnerAbstract:Semiclassical spectra weighted with products of Diagonal Matrix elements of operators A(alpha), i.e., g(alphaalpha')(E)= summation operator(n) /(E-E(n)), are obtained by harmonic inversion of a cross-correlation signal constructed of classical periodic orbits. The method provides highly resolved semiclassical spectra even in situations of nearly degenerate states, and opens the way to reducing the required signal lengths to shorter than the Heisenberg time. This implies a significant reduction of the number of orbits required for periodic orbit quantization by harmonic inversion.
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Semiclassical spectra and Diagonal Matrix elements by harmonic inversion of cross-correlated periodic orbit sums.
Physical review. E Statistical physics plasmas fluids and related interdisciplinary topics, 1999Co-Authors: J Main, K Weibert, V A Mandelshtam, G WunnerAbstract:Semiclassical spectra weighted with products of Diagonal Matrix elements of operators A(alpha), i.e., g(alphaalpha')(E)= summation operator(n)
