The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Viraht Sahni - One of the best experts on this subject based on the ideXlab platform.
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generalized hohenberg kohn theorems in electrostatic and Magnetostatic Fields
2016Co-Authors: Viraht SahniAbstract:The Hohenberg-Kohn theorems for a system of N electrons in an external electrostatic field are generalized to the added presence of a uniform Magnetostatic field. The theorems are proved for Hamiltonians of both spinless electrons and electrons with spin. It is thereby shown that the basic variables in each case are the nondegenerate ground state density \(\rho ({\mathbf {r}})\) and physical current density \({\mathbf {j}} ({\mathbf {r}})\), i.e. knowledge of \(\{ \rho ({\mathbf {r}}), {\mathbf {j}} ({\mathbf {r}}) \}\) uniquely determines the external scalar \(v ({\mathbf {r}})\) and vector \({\mathbf {A}} ({\mathbf {r}})\) potentials to within a constant and the gradient of a scalar function, respectively. The proofs differ from the original HK proof because the relationship between the potentials \(\{v ({\mathbf {r}}), {\mathbf {A}} ({\mathbf {r}}) \}\) and the nondegenerate ground state wave function is no longer one-to-one but many-to-one. Further, in addition to the constraint in the original HK proof of fixed electron number N, the constraint of fixed canonical orbital angular momentum \({\mathbf {L}}\) (for spin less electrons) and the added constraint of fixed spin angular momentum \({\mathbf {S}}\) (for electrons with spin) is required. The consequence of these proofs to the existing spin and current density functional theories is remarked upon.
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hohenberg kohn theorems in electrostatic and uniform Magnetostatic Fields
Journal of Chemical Physics, 2015Co-Authors: Xiaoyin Pan, Viraht SahniAbstract:The Hohenberg-Kohn (HK) theorems of bijectivity between the external scalar potential and the gauge invariant nondegenerate ground state density, and the consequent Euler variational principle for the density, are proved for arbitrary electrostatic field and the constraint of fixed electron number. The HK theorems are generalized for spinless electrons to the added presence of an external uniform Magnetostatic field by introducing the new constraint of fixed canonical orbital angular momentum. Thereby, a bijective relationship between the external scalar and vector potentials, and the gauge invariant nondegenerate ground state density and physical current density, is proved. A corresponding Euler variational principle in terms of these densities is also developed. These theorems are further generalized to electrons with spin by imposing the added constraint of fixed canonical orbital and spin angular momenta. The proofs differ from the original HK proof and explicitly account for the many-to-one relationship between the potentials and the nondegenerate ground state wave function. A Percus-Levy-Lieb constrained-search proof expanding the domain of validity to N-representable functions, and to degenerate states, again for fixed electron number and angular momentum, is also provided.
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hohenberg kohn theorems in electrostatic and uniform Magnetostatic Fields
arXiv: Strongly Correlated Electrons, 2015Co-Authors: Xiaoyin Pan, Viraht SahniAbstract:The Hohenberg-Kohn (HK) theorems of bijectivity between the external scalar potential and the gauge invariant nondegenerate ground state density, and the consequent Euler variational principle for the density, are proved for arbitrary electrostatic field and the constraint of fixed electron number. The HK theorems are generalized for spinless electrons to the added presence of an external uniform Magnetostatic field by introducing the new constraint of fixed canonical orbital angular momentum. Thereby a bijective relationship between the external scalar and vector potentials, and the gauge invariant nondegenerate ground state density and physical current density, is proved. A corresponding Euler variational principle in terms of these densities is also developed. These theorems are further generalized to electrons with spin by imposing the added constraint of fixed canonical orbital and spin angular momentum. The proofs differ from the original HK proof, and explicitly account for the many-to-one relationship between the potentials and the nondegenerate ground state wave function.
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Wave function for harmonically confined electrons in time-dependent electric and Magnetostatic Fields.
The Journal of chemical physics, 2014Co-Authors: Hong-ming Zhu, Xiaoyin Pan, Jin-wang Chen, Viraht SahniAbstract:We derive via the interaction “representation” the many-body wave function for harmonically confined electrons in the presence of a Magnetostatic field and perturbed by a spatially homogeneous time-dependent electric field—the Generalized Kohn Theorem (GKT) wave function. In the absence of the harmonic confinement – the uniform electron gas – the GKT wave function reduces to the Kohn Theorem wave function. Without the Magnetostatic field, the GKT wave function is the Harmonic Potential Theorem wave function. We further prove the validity of the connection between the GKT wave function derived and the system in an accelerated frame of reference. Finally, we provide examples of the application of the GKT wave function.
Xiaoyin Pan - One of the best experts on this subject based on the ideXlab platform.
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hohenberg kohn theorems in electrostatic and uniform Magnetostatic Fields
Journal of Chemical Physics, 2015Co-Authors: Xiaoyin Pan, Viraht SahniAbstract:The Hohenberg-Kohn (HK) theorems of bijectivity between the external scalar potential and the gauge invariant nondegenerate ground state density, and the consequent Euler variational principle for the density, are proved for arbitrary electrostatic field and the constraint of fixed electron number. The HK theorems are generalized for spinless electrons to the added presence of an external uniform Magnetostatic field by introducing the new constraint of fixed canonical orbital angular momentum. Thereby, a bijective relationship between the external scalar and vector potentials, and the gauge invariant nondegenerate ground state density and physical current density, is proved. A corresponding Euler variational principle in terms of these densities is also developed. These theorems are further generalized to electrons with spin by imposing the added constraint of fixed canonical orbital and spin angular momenta. The proofs differ from the original HK proof and explicitly account for the many-to-one relationship between the potentials and the nondegenerate ground state wave function. A Percus-Levy-Lieb constrained-search proof expanding the domain of validity to N-representable functions, and to degenerate states, again for fixed electron number and angular momentum, is also provided.
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hohenberg kohn theorems in electrostatic and uniform Magnetostatic Fields
arXiv: Strongly Correlated Electrons, 2015Co-Authors: Xiaoyin Pan, Viraht SahniAbstract:The Hohenberg-Kohn (HK) theorems of bijectivity between the external scalar potential and the gauge invariant nondegenerate ground state density, and the consequent Euler variational principle for the density, are proved for arbitrary electrostatic field and the constraint of fixed electron number. The HK theorems are generalized for spinless electrons to the added presence of an external uniform Magnetostatic field by introducing the new constraint of fixed canonical orbital angular momentum. Thereby a bijective relationship between the external scalar and vector potentials, and the gauge invariant nondegenerate ground state density and physical current density, is proved. A corresponding Euler variational principle in terms of these densities is also developed. These theorems are further generalized to electrons with spin by imposing the added constraint of fixed canonical orbital and spin angular momentum. The proofs differ from the original HK proof, and explicitly account for the many-to-one relationship between the potentials and the nondegenerate ground state wave function.
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Wave function for harmonically confined electrons in time-dependent electric and Magnetostatic Fields.
The Journal of chemical physics, 2014Co-Authors: Hong-ming Zhu, Xiaoyin Pan, Jin-wang Chen, Viraht SahniAbstract:We derive via the interaction “representation” the many-body wave function for harmonically confined electrons in the presence of a Magnetostatic field and perturbed by a spatially homogeneous time-dependent electric field—the Generalized Kohn Theorem (GKT) wave function. In the absence of the harmonic confinement – the uniform electron gas – the GKT wave function reduces to the Kohn Theorem wave function. Without the Magnetostatic field, the GKT wave function is the Harmonic Potential Theorem wave function. We further prove the validity of the connection between the GKT wave function derived and the system in an accelerated frame of reference. Finally, we provide examples of the application of the GKT wave function.
L. Hurd - One of the best experts on this subject based on the ideXlab platform.
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Self-generated surface magnetic Fields inhibit laser-driven sheath acceleration of high-energy protons
Nature Communications, 2018Co-Authors: M. Nakatsutsumi, Y. Sentoku, A. Korzhimanov, S. Chen, S. Buffechoux, A. Kon, B. Atherton, P. Audebert, M. Geissel, L. HurdAbstract:High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric Fields around the target. The proton beams accelerated in such Fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that Magnetostatic Fields self-generated on the target surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those Fields can be strong enough (~10$^5$ T at laser intensities ~10$^{21}$ W cm$^{–2}$) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire.
M Baillygrandvaux - One of the best experts on this subject based on the ideXlab platform.
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laser driven strong Magnetostatic Fields with applications to charged beam transport and magnetized high energy density physics
Physics of Plasmas, 2018Co-Authors: J J Santos, M Baillygrandvaux, Dimitri Batani, M Ehret, Alexey Arefiev, F N Beg, A Calisti, S FerriAbstract:Powerful nanosecond laser-plasma processes are explored to generate discharge currents of a few 100 kA in coil targets, yielding Magnetostatic Fields (B-Fields) in excess of 0.5 kT. The quasi-static currents are provided from hot electron ejection from the laser-irradiated surface. According to our model, which describes the evolution of the discharge current, the major control parameter is the laser irradiance Ilasλlas2. The space-time evolution of the B-Fields is experimentally characterized by high-frequency bandwidth B-dot probes and proton-deflectometry measurements. The magnetic pulses, of ns-scale, are long enough to magnetize secondary targets through resistive diffusion. We applied it in experiments of laser-generated relativistic electron transport through solid dielectric targets, yielding an unprecedented 5-fold enhancement of the energy-density flux at 60 μm depth, compared to unmagnetized transport conditions. These studies pave the ground for magnetized high-energy density physics investigations, related to laser-generated secondary sources of radiation and/or high-energy particles and their transport, to high-gain fusion energy schemes, and to laboratory astrophysics.Powerful nanosecond laser-plasma processes are explored to generate discharge currents of a few 100 kA in coil targets, yielding Magnetostatic Fields (B-Fields) in excess of 0.5 kT. The quasi-static currents are provided from hot electron ejection from the laser-irradiated surface. According to our model, which describes the evolution of the discharge current, the major control parameter is the laser irradiance Ilasλlas2. The space-time evolution of the B-Fields is experimentally characterized by high-frequency bandwidth B-dot probes and proton-deflectometry measurements. The magnetic pulses, of ns-scale, are long enough to magnetize secondary targets through resistive diffusion. We applied it in experiments of laser-generated relativistic electron transport through solid dielectric targets, yielding an unprecedented 5-fold enhancement of the energy-density flux at 60 μm depth, compared to unmagnetized transport conditions. These studies pave the ground for magnetized high-energy density physics investig...
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guiding of relativistic electron beams in dense matter by laser driven Magnetostatic Fields
Nature Communications, 2018Co-Authors: M Baillygrandvaux, P Forestiercolleoni, R Bouillaud, Dimitri Batani, J. J. Honrubia, S Fujioka, J J Santos, Lauren Giuffrida, C Bellei, Michael ChevrotAbstract:Intense lasers interacting with dense targets accelerate relativistic electron beams, which transport part of the laser energy into the target depth. However, the overall laser-to-target energy coupling efficiency is impaired by the large divergence of the electron beam, intrinsic to the laser–plasma interaction. Here we demonstrate that an efficient guiding of MeV electrons with about 30 MA current in solid matter is obtained by imposing a laser-driven longitudinal Magnetostatic field of 600 T. In the magnetized conditions the transported energy density and the peak background electron temperature at the 60-μm-thick target's rear surface rise by about a factor of five, as unfolded from benchmarked simulations. Such an improvement of energy-density flux through dense matter paves the ground for advances in laser-driven intense sources of energetic particles and radiation, driving matter to extreme temperatures, reaching states relevant for planetary or stellar science as yet inaccessible at the laboratory scale and achieving high-gain laser-driven thermonuclear fusion. Efficient energy transport by laser-driven relativistic electron beams is crucial in many applications including inertial confinement fusion, and particle acceleration. Here the authors demonstrate relativistic electron beam guiding in dense plasma with an externally imposed high magnetic field.
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laser driven strong Magnetostatic Fields with applications to charged beam transport and magnetized high energy density physics
arXiv: Plasma Physics, 2017Co-Authors: J J Santos, M Baillygrandvaux, Dimitri Batani, M Ehret, Alexey Arefiev, F N Beg, A Calisti, S FerriAbstract:Powerful laser-plasma processes are explored to generate discharge currents of a few $100\,$kA in coil targets, yielding Magnetostatic Fields (B-Fields) in excess of $0.5\,$kT. The quasi-static currents are provided from hot electron ejection from the laser-irradiated surface. According to our model, describing qualitatively the evolution of the discharge current, the major control parameter is the laser irradiance $I_{\mathrm{las}}\lambda_{\mathrm{las}}^2$. The space-time evolution of the B-Fields is experimentally characterized by high-frequency bandwidth B-dot probes and by proton-deflectometry measurements. The magnetic pulses, of ns-scale, are long enough to magnetize secondary targets through resistive diffusion. We applied it in experiments of laser-generated relativistic electron transport into solid dielectric targets, yielding an unprecedented 5-fold enhancement of the energy-density flux at $60 \,\mathrm{\mu m}$ depth, compared to unmagnetized transport conditions. These studies pave the ground for magnetized high-energy density physics investigations, related to laser-generated secondary sources of radiation and/or high-energy particles and their transport, to high-gain fusion energy schemes and to laboratory astrophysics.
D Altbir - One of the best experts on this subject based on the ideXlab platform.
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Synchronization of two spin-transfer-driven nano-oscillators coupled via Magnetostatic Fields.
Physical review. E, 2019Co-Authors: D Mancilla-almonacid, Alejandro O Leon, R E Arias, S Allende, D AltbirAbstract:The magnetization dynamics of nano-oscillators may be excited by both magnetic Fields and spin-polarized currents. While the dynamics of single oscillators has been well characterized, the synchronization of several ones is not fully understood yet. An analytical and numerical study of the nonlinear dynamics of two Magnetostatically coupled spin valves driven by spin-transfer torques is presented under the macrospin approximation. The oscillators interact via Magnetostatic Fields and exhibit a robust synchronized magnetization motion. We describe the magnetization dynamics of the system using the Landau-Lifshitz-Gilbert-Slonczewski equation. Using a modal decomposition technique, we describe the dynamics, synchronization, and competition of oscillatory modes as a function of the current density, and the geometrical parameters of the setup. Simulations of the Landau-Lifshitz-Gilbert-Slonczewski equation show good agreement with an approximate analytic solution.