The Experts below are selected from a list of 32616 Experts worldwide ranked by ideXlab platform
Hugo Reinhardt - One of the best experts on this subject based on the ideXlab platform.
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Variational approach to Yang–Mills theory with non-Gaussian Wave functionals
Progress in Particle and Nuclear Physics, 2012Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:Abstract A general method for treating non-Gaussian Wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang–Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum Wave functional. The three-gluon and ghost–gluon vertices are calculated using the propagators found in the variational approach with a Gaussian trial Wave functional as input.
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Variational Approach to Yang‐Mills Theory with non‐Gaussian Wave Functionals
2011Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:A general method for treating non‐Gaussian Wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang‐Mills theory in Coulomb gauge in order to include a three‐gluon kernel in the exponential of the vacuum Wave functional. The three‐gluon vertex is calculated using the propagators found in the variational approach with a Gaussian trial Wave functional as input.
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non Gaussian Wave functionals in coulomb gauge yang mills theory
Physical Review D, 2010Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:A general method to treat non-Gaussian vacuum Wave functionals in the Hamiltonian formulation of a quantum field theory is presented. By means of Dyson-Schwinger techniques, the static Green functions are expressed in terms of the kernels arising in the Taylor expansion of the exponent of the vacuum Wave functional. These kernels are then determined by minimizing the vacuum expectation value of the Hamiltonian. The method is applied to Yang-Mills theory in Coulomb gauge, using a vacuum Wave functional whose exponent contains up to quartic terms in the gauge field. An estimate of the cubic and quartic interaction kernels is given using as input the gluon and ghost propagators found with a Gaussian Wave functional.
Davide R. Campagnari - One of the best experts on this subject based on the ideXlab platform.
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Variational approach to Yang–Mills theory with non-Gaussian Wave functionals
Progress in Particle and Nuclear Physics, 2012Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:Abstract A general method for treating non-Gaussian Wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang–Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum Wave functional. The three-gluon and ghost–gluon vertices are calculated using the propagators found in the variational approach with a Gaussian trial Wave functional as input.
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Variational Approach to Yang‐Mills Theory with non‐Gaussian Wave Functionals
2011Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:A general method for treating non‐Gaussian Wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang‐Mills theory in Coulomb gauge in order to include a three‐gluon kernel in the exponential of the vacuum Wave functional. The three‐gluon vertex is calculated using the propagators found in the variational approach with a Gaussian trial Wave functional as input.
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non Gaussian Wave functionals in coulomb gauge yang mills theory
Physical Review D, 2010Co-Authors: Davide R. Campagnari, Hugo ReinhardtAbstract:A general method to treat non-Gaussian vacuum Wave functionals in the Hamiltonian formulation of a quantum field theory is presented. By means of Dyson-Schwinger techniques, the static Green functions are expressed in terms of the kernels arising in the Taylor expansion of the exponent of the vacuum Wave functional. These kernels are then determined by minimizing the vacuum expectation value of the Hamiltonian. The method is applied to Yang-Mills theory in Coulomb gauge, using a vacuum Wave functional whose exponent contains up to quartic terms in the gauge field. An estimate of the cubic and quartic interaction kernels is given using as input the gluon and ghost propagators found with a Gaussian Wave functional.
Günter Wunner - One of the best experts on this subject based on the ideXlab platform.
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Time propagation of constrained coupled Gaussian Wave packets.
The Journal of chemical physics, 2008Co-Authors: Tomaž Fabčič, Jörg Main, Günter WunnerAbstract:The dynamics of quantum systems can be approximated by the time propagation of Gaussian Wave packets. Applying a time dependent variational principle, the time evolution of the parameters of the coupled Gaussian Wave packets can be calculated from a set of ordinary differential equations. Unfortunately, the set of equations is ill behaved in most practical applications, depending on the number of propagated Gaussian Wave packets, and methods for regularization are needed. We present a general method for regularization based on applying adequate nonholonomic inequality constraints to the evolution of the parameters, keeping the equations of motion well behaved. The power of the method is demonstrated for a nonintegrable system with two degrees of freedom.
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Gaussian Wave Packet Dynamics in the Diamagnetic H-Atom
2007Co-Authors: Tomaž Fabčič, Günter WunnerAbstract:The method of Gaussian Wave packet (GWP) propagation introduced by Heller is a popular tool for doing time dependent quantum mechanical calculations in particular in molecular and nuclear physics. We show that this method is also applicable to atomic systems. We concentrate on the H-atom in a strong magnetic field, where a well-known regularization is used to remove the singularity. The Coulomb potential is transformed to a harmonic potential making GWP especially suitable. All equations of motion are obtained in analytic form. The matrix singularity problem encountered in the equations of motion derived from a time dependent variational principle is overcome by using a singular value decomposition (SVD).
David P. Tew - One of the best experts on this subject based on the ideXlab platform.
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A Gaussian Wave packet phase-space representation of quantum canonical statistics
The Journal of chemical physics, 2015Co-Authors: David J. Coughtrie, David P. TewAbstract:We present a mapping of quantum canonical statistical averages onto a phase-space average over thawed Gaussian Wave-packet (GWP) parameters, which is exact for harmonic systems at all temperatures. The mapping invokes an effective potential surface, experienced by the Wave packets, and a temperature-dependent phase-space integrand, to correctly transition from the GWP average at low temperature to classical statistics at high temperature. Numerical tests on weakly and strongly anharmonic model systems demonstrate that thermal averages of the system energy and geometric properties are accurate to within 1% of the exact quantum values at all temperatures.
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The Nosé-Hoover looped chain thermostat for low temperature thawed Gaussian Wave-packet dynamics.
The Journal of chemical physics, 2014Co-Authors: David J. Coughtrie, David P. TewAbstract:We have used a generalised coherent state resolution of the identity to map the quantum canonical statistical average for a general system onto a phase-space average over the centre and width parameters of a thawed Gaussian Wave packet. We also propose an artificial phase-space density that has the same behaviour as the canonical phase-space density in the low-temperature limit, and have constructed a novel Nose–Hoover looped chain thermostat that generates this density in conjunction with variational thawed Gaussian Wave-packet dynamics. This forms a new platform for evaluating statistical properties of quantum condensed-phase systems that has an explicit connection to the time-dependent Schrodinger equation, whilst retaining many of the appealing features of path-integral molecular dynamics.
Fabricio Toscano - One of the best experts on this subject based on the ideXlab platform.
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Semiclassical propagation of Gaussian Wave packets.
Physical review letters, 2008Co-Authors: Raphael N. P. Maia, F. Nicacio, Raúl O. Vallejos, Fabricio ToscanoAbstract:We analyze the semiclassical evolution of Gaussian Wave packets in chaotic systems. We show that after some short time a Gaussian Wave packet becomes a primitive WKB state. From then on, the state can be propagated using the standard time-dependent WKB scheme. Complex trajectories are not necessary to account for the long-time propagation. The Wigner function of the evolving state develops the structure of a classical filament plus quantum oscillations, with phase and amplitude being determined by geometric properties of a classical manifold.
