The Experts below are selected from a list of 11046 Experts worldwide ranked by ideXlab platform
Naoki Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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linear open quantum systems with passive hamiltonians and a single local Dissipative Process
Automatica, 2021Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:Abstract We consider linear open quantum systems with passive Hamiltonians and a single, local Dissipative Process. Generally speaking, these systems are easier to implement than systems with active Hamiltonians and non-local Dissipative Processes. We parametrize the set of all covariance matrices corresponding to pure Gaussian steady states that can be achieved by this type of quantum system. Given such pure states, we parametrize the corresponding linear quantum systems with passive Hamiltonians and a single, local Dissipative Process that generate them.
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pure gaussian states from quantum harmonic oscillator chains with a single local Dissipative Process
Journal of Physics A, 2017Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We study the preparation of entangled pure Gaussian states via reservoir engineering. In particular, we consider a chain consisting of quantum harmonic oscillators where the central oscillator of the chain is coupled to a single reservoir. We then completely parametrize the class of -mode pure Gaussian states that can be prepared by this type of quantum harmonic oscillator chain. This parametrization allows us to determine the steady-state entanglement properties of such quantum harmonic oscillator chains.
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pure gaussian states from quantum harmonic oscillator chains with a single local Dissipative Process
arXiv: Quantum Physics, 2016Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We study the preparation of entangled pure Gaussian states via reservoir engineering. In particular, we consider a chain consisting of $(2\aleph+1)$ quantum harmonic oscillators where the central oscillator of the chain is coupled to a single reservoir. We then completely parametrize the class of $(2\aleph+1)$-mode pure Gaussian states that can be prepared by this type of quantum harmonic oscillator chain. This parametrization allows us to determine the steady-state entanglement properties of such quantum harmonic oscillator chains.
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pure gaussian quantum states from passive hamiltonians and an active local Dissipative Process
arXiv: Quantum Physics, 2016Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We investigate the problem of preparing a pure Gaussian state via reservoir engineering. In particular, we consider a linear quantum system with a passive Hamiltonian and with a single reservoir which acts only on a single site of the system. We then give a full parametrization of the pure Gaussian states that can be prepared by this type of quantum system.
Alberto Salvadori - One of the best experts on this subject based on the ideXlab platform.
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fracture propagation in brittle materials as a standard Dissipative Process effective crack tracking algorithms based on a viscous regularization
Journal of The Mechanics and Physics of Solids, 2019Co-Authors: Alberto Salvadori, Paul A Wawrzynek, Francesca FantoniAbstract:Abstract Cracks propagation in brittle materials was framed into the theory of standard Dissipative Processes by several authors in many publications. Although the theoretical setting is sound, the derived crack tracking methods suffered from a major drawback that limited the interest in the method to its theoretical content. Specifically, the need of currently unavailable accurate approximations for weight functions made the approach numerically of minor interest. Such a drawback is overcome in the present note, where a viscous regularization of the fracture propagation in brittle materials as a standard Dissipative Process is formulated. Rate-dependency provided a simple and effective approximation of the crack front velocity, thus allowing to formulate crack tracking algorithms that seem to show promising potential.
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fracture propagation in brittle materials as a standard Dissipative Process general theorems and crack tracking algorithms
Journal of The Mechanics and Physics of Solids, 2016Co-Authors: Alberto Salvadori, Francesca FantoniAbstract:Abstract The present work frames the problem of three-dimensional quasi-static crack propagation in brittle materials into the theory of standard Dissipative Processes. Variational formulations are stated. They characterize the three dimensional crack front “quasi-static velocity” as minimizer of constrained quadratic functionals. An implicit in time crack tracking algorithm that computationally handles the constraint via the penalty method algorithm is introduced and proof of concept is provided.
Francesca Fantoni - One of the best experts on this subject based on the ideXlab platform.
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fracture propagation in brittle materials as a standard Dissipative Process effective crack tracking algorithms based on a viscous regularization
Journal of The Mechanics and Physics of Solids, 2019Co-Authors: Alberto Salvadori, Paul A Wawrzynek, Francesca FantoniAbstract:Abstract Cracks propagation in brittle materials was framed into the theory of standard Dissipative Processes by several authors in many publications. Although the theoretical setting is sound, the derived crack tracking methods suffered from a major drawback that limited the interest in the method to its theoretical content. Specifically, the need of currently unavailable accurate approximations for weight functions made the approach numerically of minor interest. Such a drawback is overcome in the present note, where a viscous regularization of the fracture propagation in brittle materials as a standard Dissipative Process is formulated. Rate-dependency provided a simple and effective approximation of the crack front velocity, thus allowing to formulate crack tracking algorithms that seem to show promising potential.
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fracture propagation in brittle materials as a standard Dissipative Process general theorems and crack tracking algorithms
Journal of The Mechanics and Physics of Solids, 2016Co-Authors: Alberto Salvadori, Francesca FantoniAbstract:Abstract The present work frames the problem of three-dimensional quasi-static crack propagation in brittle materials into the theory of standard Dissipative Processes. Variational formulations are stated. They characterize the three dimensional crack front “quasi-static velocity” as minimizer of constrained quadratic functionals. An implicit in time crack tracking algorithm that computationally handles the constraint via the penalty method algorithm is introduced and proof of concept is provided.
A C M Correia - One of the best experts on this subject based on the ideXlab platform.
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the harps search for southern extra solar planets xix characterization and dynamics of the gj 876 planetary system
Astronomy and Astrophysics, 2010Co-Authors: A C M Correia, J Couetdic, Jacques Laskar, X Bonfils, M Mayor, Jeanloup Bertaux, F Bouchy, X Delfosse, T ForveilleAbstract:Precise radial-velocity measurements for data acquired with the HARPS spectrograph infer that three planets orbit the M4 dwarf star GJ876. In particular, we confirm the existence of planet d, which orbits every 1.93785 days. We find that its orbit may have significant eccentricity (e = 0.14), and deduce a more accurate estimate of its minimum mass of 6.3 M⊕. Dynamical modeling of the HARPS measurements combined with literature velocities from the Keck Observatory strongly constrain the orbital inclinations of the b and c planets. We find that ib = 48.9 ◦ ± 1.0 ◦ and ic = 48.1 ◦ ± 2.1 ◦ , which infers the true planet masses of Mb = 2.64 ± 0.04 MJup and Mc = 0.83 ± 0.03 MJup, respectively. Radial velocities alone, in this favorable case, can therefore fully determine the orbital architecture of a multi-planet system, without the input from astrometry or transits. The orbits of the two giant planets are nearly coplanar, and their 2:1 mean motion resonance ensures stability over at least 5 Gyr. The libration amplitude is smaller than 2 ◦ , suggesting that it was damped by some Dissipative Process during planet formation. The system has space for a stable fourth planet in a 4:1 mean motion resonance with planet b, with a period around 15 days. The radial velocity measurements constrain the mass of this possible additional planet to be at most that of the Earth.
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the harps search for southern extra solar planets xix characterization and dynamics of the gj876 planetary system
arXiv: Earth and Planetary Astrophysics, 2010Co-Authors: A C M Correia, J Couetdic, Jacques Laskar, X Bonfils, M Mayor, Jeanloup Bertaux, F Bouchy, X Delfosse, T Forveille, C LovisAbstract:Precise radial-velocity measurements for data acquired with the HARPS spectrograph infer that three planets orbit the M4 dwarf star GJ876. In particular, we confirm the existence of planet "d", which orbits every 1.93785 days. We find that its orbit may have significant eccentricity (e=0.14), and deduce a more accurate estimate of its minimum mass of 6.3 Earth masses. Dynamical modeling of the HARPS measurements combined with literature velocities from the Keck Observatory strongly constrain the orbital inclinations of the "b" and "c" planets. We find that i_b = 48.9 degrees and i_c = 48.1 degrees, which infers the true planet masses of M_b = 2.64 Jupiter masses and M_c = 0.83 Jupiter masses, respectively. Radial velocities alone, in this favorable case, can therefore fully determine the orbital architecture of a multi-planet system, without the input from astrometry or transits. The orbits of the two giant planets are nearly coplanar, and their 2:1 mean motion resonance ensures stability over at least 5 Gyr. The libration amplitude is smaller than 2 degrees, suggesting that it was damped by some Dissipative Process during planet formation. The system has space for a stable fourth planet in a 4:1 mean motion resonance with planet "b", with a period around 15 days. The radial velocity measurements constrain the mass of this possible additional planet to be at most that of the Earth.
Matthew J Woolley - One of the best experts on this subject based on the ideXlab platform.
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linear open quantum systems with passive hamiltonians and a single local Dissipative Process
Automatica, 2021Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:Abstract We consider linear open quantum systems with passive Hamiltonians and a single, local Dissipative Process. Generally speaking, these systems are easier to implement than systems with active Hamiltonians and non-local Dissipative Processes. We parametrize the set of all covariance matrices corresponding to pure Gaussian steady states that can be achieved by this type of quantum system. Given such pure states, we parametrize the corresponding linear quantum systems with passive Hamiltonians and a single, local Dissipative Process that generate them.
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pure gaussian states from quantum harmonic oscillator chains with a single local Dissipative Process
Journal of Physics A, 2017Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We study the preparation of entangled pure Gaussian states via reservoir engineering. In particular, we consider a chain consisting of quantum harmonic oscillators where the central oscillator of the chain is coupled to a single reservoir. We then completely parametrize the class of -mode pure Gaussian states that can be prepared by this type of quantum harmonic oscillator chain. This parametrization allows us to determine the steady-state entanglement properties of such quantum harmonic oscillator chains.
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pure gaussian states from quantum harmonic oscillator chains with a single local Dissipative Process
arXiv: Quantum Physics, 2016Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We study the preparation of entangled pure Gaussian states via reservoir engineering. In particular, we consider a chain consisting of $(2\aleph+1)$ quantum harmonic oscillators where the central oscillator of the chain is coupled to a single reservoir. We then completely parametrize the class of $(2\aleph+1)$-mode pure Gaussian states that can be prepared by this type of quantum harmonic oscillator chain. This parametrization allows us to determine the steady-state entanglement properties of such quantum harmonic oscillator chains.
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pure gaussian quantum states from passive hamiltonians and an active local Dissipative Process
arXiv: Quantum Physics, 2016Co-Authors: Matthew J Woolley, Ian R Petersen, Naoki YamamotoAbstract:We investigate the problem of preparing a pure Gaussian state via reservoir engineering. In particular, we consider a linear quantum system with a passive Hamiltonian and with a single reservoir which acts only on a single site of the system. We then give a full parametrization of the pure Gaussian states that can be prepared by this type of quantum system.