2,853 research outputs found
Level Set Dynamics and the Non-blowup of the 2D Quasi-geostrophic Equation
In this article we apply the technique proposed in Deng-Hou-Yu (Comm. PDE,
2005) to study the level set dynamics of the 2D quasi-geostrophic equation.
Under certain assumptions on the local geometric regularity of the level sets
of , we obtain global regularity results with improved growth estimate
on . We further perform numerical simulations to
study the local geometric properties of the level sets near the region of
maximum . The numerical results indicate that the
assumptions on the local geometric regularity of the level sets of in
our theorems are satisfied. Therefore these theorems provide a good explanation
of the double exponential growth of observed in this
and past numerical simulations.Comment: 25 pages, 10 figures. Corrected a few typo
Deterministic spin-wave interferometer based on Rydberg blockade
The spin-wave (SW) NOON state is an -particle Fock state with two atomic
spin-wave modes maximally entangled. Attributed to the property that the phase
is sensitive to collective atomic motion, the SW NOON state can be utilized as
a novel atomic interferometer and has promising application in quantum enhanced
measurement. In this paper we propose an efficient protocol to
deterministically produce the atomic SW NOON state by employing Rydberg
blockade. Possible errors in practical manipulations are analyzed. A feasible
experimental scheme is suggested. Our scheme is far more efficient than the
recent experimentally demonstrated one, which only creates a heralded
second-order SW NOON state.Comment: 5 pages, 2 figure
Remote information concentration and multipartite entanglement in multilevel systems
Remote information concentration (RIC) in -level systems (qudits) is
studied. It is shown that the quantum information initially distributed in
three spatially separated qudits can be remotely and deterministically
concentrated to a single qudit via an entangled channel without performing any
global operations. The entangled channel can be different types of genuine
multipartite pure entangled states which are inequivalent under local
operations and classical communication. The entangled channel can also be a
mixed entangled state, even a bound entangled state which has a similar form to
the Smolin state, but has different features from the Smolin state. A common
feature of all these pure and mixed entangled states is found, i.e., they have
common commuting stabilizers. The differences of qudit-RIC and qubit-RIC
() are also analyzed.Comment: 10 pages, 3 figure
(1H-Benzimidazole-5-carboxylic acid-κN 3)(1H-benzimidazole-6-carboxylic acid-κN 3)silver(I) perchlorate
The reaction of 1H-benzimidazole-5-carboxylic acid with silver nitrate in the presence of perchloric acid under hydrothermal conditions yielded the title complex, [Ag(C8H6N2O2)2]ClO4, which comprises of an [Ag(C8H6N2O2)2] mononuclear cation and a perchlorate anion. The AgI ion is coordinated by two N atoms from two different neutral 1H-benzimidazole-5-carboxylic acid ligands with an N—Ag—N bond angle of 163.21 (14)°, forming an [Ag(C8H6N2O2)2] mononuclear cation. Although both ligands in the mononuclear cation are monodentate with one N atom coordinated to the metal ion, they are different: one is N3 coordinated to the Ag I ion and the N1 atom protonated, the other with the N1 coordinated to the Ag I ion and the N3 atom protonated (and thus formally a 1H-benzimidazole-6-carboxylic acid rather than a 1H-benzimidazole-5-carboxylic acid ligand). The planes of the two planar ligands are roughly perpendicular, making a dihedral angle of 84.97 (2)°. The packing of the ions is stablized by extensive O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, and by remote Ag⋯O interactions [3.002 (3), 3.581 (5) and 3.674 (5) Å]
Tall offshore steel wind turbine towers under wind, current and wave loading:an experimental and numerical study
A PAWL for Enhancing Strength and Endurance during Walking Using Interaction Force and Dynamical Information
Imaginary polarization as a way to surmount the sign problem in ab initio calculations of spin-imbalanced Fermi gases
From ultracold atoms to quantum chromodynamics, reliable ab initio studies of
strongly interacting fermions require numerical methods, typically in some form
of quantum Monte Carlo calculation. Unfortunately, (non)relativistic systems at
finite density (spin polarization) generally have a sign problem, such that
those ab initio calculations are impractical. It is well-known, however, that
in the relativistic case imaginary chemical potentials solve this problem,
assuming the data can be analytically continued to the real axis. Is this
feasible for nonrelativistic systems? Are the interesting features of the phase
diagram accessible in this manner? By introducing complex chemical potentials,
for real total particle number and imaginary polarization, the sign problem is
avoided in the nonrelativistic case. To give a first answer to the above
questions, we perform a mean-field study of the finite-temperature phase
diagram of spin-1/2 fermions with imaginary polarization.Comment: 5 pages, 2 figures; published versio
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