Results 81 to 90 of about 17,286,981 (307)

Change in Hamiltonian General Relativity from the Lack of a Time-like Killing Vector Field [PDF]

open access: yes, 2013
In General Relativity in Hamiltonian form, change has seemed to be missing, defined only asymptotically, or otherwise obscured at best, because the Hamiltonian is a sum of first-class constraints and a boundary term and thus supposedly generates gauge ...
Pitts, J. Brian, J. Brian Pitts
core  

A First Class Constraint Generates Not a Gauge Transformation, But a Bad Physical Change: The Case of Electromagnetism [PDF]

open access: yes, 2013
In Dirac-Bergmann constrained dynamics, a first-class constraint typically does not _alone_ generate a gauge transformation. By direct calculation it is found that each first-class constraint in Maxwell's theory generates a change in the electric field ...
Pitts, J. Brian, J. Brian Pitts
core   +2 more sources

Trions as Fundamental Species in Chemically Doped Polymer Semiconductors

open access: yesAdvanced Materials, EarlyView.
This work shows that exciton–charge carrier coupling in doped polymer semiconductors gives rise to multi‐particle states, including trions—quasiparticles consisting of two holes and one electron under p‐doping—and bound exciton‐hole pairs, as identified through spectroscopic and theoretical analysis.
Hongmo Li   +23 more
wiley   +1 more source

Non-hyperbolic P-Invariant Closed Characteristics on Partially Symmetric Compact Convex Hypersurfaces

open access: yesAdvanced Nonlinear Studies, 2018
Let n≥2{n\geq 2} be an integer, P=diag⁢(-In-κ,Iκ,-In-κ,Iκ){P=\mathrm{diag}(-I_{n-\kappa},I_{\kappa},-I_{n-\kappa},I_{\kappa})} for some integer κ∈[0,n]{\kappa\in[0,n]}, and let Σ⊂ℝ2⁢n{\Sigma\subset{\mathbb{R}}^{2n}} be a partially symmetric compact ...
Liu Hui, Zhu Gaosheng
doaj   +1 more source

Weak In‐Plane Ferromagnetism and Electronic Nematicity in the Distorted Triple‐Q Magnetic Phase of Co1/3TaS2

open access: yesAdvanced Materials, EarlyView.
Co1/3TaS2${\rm Co}_{1/3}{\rm TaS}_{2}$ hosts a triple‐Q noncoplanar antiferromagnetic state with coexisting Z3${\rm Z}_3$ electronic nematicity. We report rotational hysteresis observed in both magnetoresistance and magnetic torque, revealing strongly pinned in‐plane weak ferromagnetic moments in the triple‐Q phase and the magnetism‐driven nature of ...
Joonyoung Choi   +5 more
wiley   +1 more source

Existence of a ground-state solution for a quasilinear Schrödinger system

open access: yesFrontiers in Physics
In this paper, we consider the following quasilinear Schrödinger system.−Δu+u+k2Δ|u|2u=2αα+β|u|α−2u|v|β,x∈RN,−Δv+v+k2Δ|v|2v=2βα+β|u|α|v|β−2v,x∈RN,where k < 0 is a real constant, α > 1, β > 1, and α + β < 2*.
Xue Zhang   +3 more
doaj   +1 more source

Time-Dependent Hamiltonian Reconstruction Using Continuous Weak Measurements

open access: yesPRX Quantum, 2023
Reconstructing the Hamiltonian of a quantum system is an essential task for characterizing and certifying quantum processors and simulators. Existing techniques either rely on projective measurements of the system before and after coherent time evolution
Karthik Siva   +11 more
doaj   +1 more source

Ferromagnetism of Molecular Beam Epitaxy‐grown Ultra‐thin Cr2Ge2Te6 Films Down to the Monolayer Limit on Si Substrates

open access: yesAdvanced Materials, EarlyView.
Uniform monolayer Cr2Ge2Te6 films are achieved on Si substrates by molecular beam epitaxy. Intrinsic ferromagnetism with perpendicular magnetic anisotropy is established in the films by anomalous Hall effect and superconducting quantum interference device measurements, albeit with strong magnetic fluctuations characteristic of its 2D nature.
Pengfei Ji   +15 more
wiley   +1 more source

Aging in an infinite-range Hamiltonian system of coupled rotators [PDF]

open access: yes, 2003
The slow relaxation dynamics of a long-range Hamiltonian system through its aging dynamics was characterized. The existence of aging in the Hamiltonian was observed, and further characterized by scaling properties reminiscent of spin glass dynamics. This
Montemurro M. A.   +5 more
core   +1 more source

Chiral Altermagnetic Magnetoelectrics

open access: yesAdvanced Materials, EarlyView.
In this work, we introduce a previously unexplored class of magnetoelectric materials, which we term chiral altermagnetic magnetoelectrics, in which structural chirality and Néel‐vector‐driven polarization are intrinsically coupled in nonpolar altermagnetic systems.
Chengwu Xie   +8 more
wiley   +1 more source

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