1,630 research outputs found
Simulating 2+1d Lattice QED with dynamical matter using ultracold atoms
We suggest a method to simulate lattice compact Quantum Electrodynamics
(cQED) using ultracold atoms in optical lattices, which includes dynamical
Dirac fermions in 2+1 dimensions. This allows to test dynamical effects of
confinement as well as 2d flux loops deformations and breaking, and to observe
Wilson-loop area-law.Comment: Includes supplementary material. Added references, minor
modification
Linear dynamics of a stably-neutrally stratified ocean
Linear dynamics of stably-neutrally stratified fluid consisting of the stably stratified upper layer and the homogeneous lower layer is studied with and without rotation. The density and other fields are continuous at the interface between the layers. A special feature of this configuration is existence of the wave mode related to the homogeneous layer. In non-rotating fluid this is the homogeneous layer vortex mode characterized by a stationary three-dimensional velocity field confined to the lower layer. In the presence of rotation, the mode turns into the gyroscopic waves. Besides the mode, the wave spectrum contains internal waves and the zero frequency horizontal vortex mode with zero vertical velocity. In non-rotating fluid, the vertical velocity consists of the dispersive internal waves and of a steady component in the homogeneous layer. With increasing time the internal waves decay at a fixed point because of dispersion, and the vertical velocity decays in the upper layer and becomes stationary in the lower layer. A non-stationary boundary layer develops near the interface in the stratified layer at large times. In rotating fluid we examined the wave spectrum not using the traditional and hydrostatic approximations, and found the spectrum consists of the super-inertial internal waves, the sub-inertial gyroscopic waves and the sub- and super-inertial internal inertio-gravity waves. In the case of strong stratification f/N \u3c\u3c 1(f is the inertial frequency and N is the stratified layer buoyancy frequency) and for the long wave scales f2/N2 \u3c\u3c H/L \u3c\u3c 1(H and L are the fluid depth and the horizontal scale), the internal and the super-inertial inertio-gravity waves freely penetrate into the lower layer, and the gyroscopic waves are localized in the lower layer and are close to the inertial oscillations. Any long-wave field of the vertical velocity is split into the internal waves, and the inertial oscillations (long gyroscopic waves) confined to the lower layer. With time, the internal waves decay because of dispersion, and the vertical velocity goes to zero in the upper layer and in the lower layer only the inertial oscillations remain
Structure, dynamics and bifurcations of discrete solitons in trapped ion crystals
We study discrete solitons (kinks) accessible in state-of-the-art trapped ion
experiments, considering zigzag crystals and quasi-3D configurations, both
theoretically and experimentally. We first extend the theoretical understanding
of different phenomena predicted and recently experimentally observed in the
structure and dynamics of these topological excitations. Employing tools from
topological degree theory, we analyze bifurcations of crystal configurations in
dependence on the trapping parameters, and investigate the formation of kink
configurations and the transformations of kinks between different structures.
This allows us to accurately define and calculate the effective potential
experienced by solitons within the Wigner crystal, and study how this
(so-called Peierls-Nabarro) potential gets modified to a nonperiodic globally
trapping potential in certain parameter regimes. The kinks' rest mass (energy)
and spectrum of modes are computed and the dynamics of linear and nonlinear
kink oscillations are analyzed. We also present novel, experimentally observed,
configurations of kinks incorporating a large-mass defect realized by an
embedded molecular ion, and of pairs of interacting kinks stable for long
times, offering the perspective for exploring and exploiting complex collective
nonlinear excitations, controllable on the quantum level.Comment: 25 pages, 10 figures, v2 corrects Fig. 2 and adds some text and
reference
Critical and noncritical long range entanglement in the Klein-Gordon field
We investigate the entanglement between two separated segments in the vacuum
state of a free 1D Klein-Gordon field, where explicit computations are
performed in the continuum limit of the linear harmonic chain. We show that the
entanglement, which we measure by the logarithmic negativity, is finite with no
further need for renormalization. We find that the quantum correlations decay
much faster than the classical correlations as in the critical limit long range
entanglement decays exponentially for separations larger than the size of the
segments. As the segments become closer to each other the entanglement diverges
as a power law. The noncritical regime manifests richer behavior, as the
entanglement depends both on the size of the segments and on their separation.
In correspondence with the von Neumann entropy long-range entanglement also
distinguishes critical from noncritical systems
Topological Wilson-loop area law manifested using a superposition of loops
We introduce a new topological effect involving interference of two meson
loops, manifesting a path-independent topological area dependence. The effect
also draws a connection between quark confinement, Wilson-loops and topological
interference effects. Although this is only a gedanken experiment in the
context of particle physics, such an experiment may be realized and used as a
tool to test confinement effects and phase transitions in quantum simulation of
dynamic gauge theories.Comment: Superceding arXiv:1206.2021v1 [quant-ph
Reforming backgrounds of the state financial inspection
Relevance of the topic. Financial and economy security of Ukraine is one of the most important elements of the national security of the State. The high level of financial and economy security allow to assist (promote) the stable functioning of the economy, ensuring favorable financial conditions for the activity subject’s economy managements and creating positive financial climate in general. To ensure that directed activity of several government agencies. For today lots of these agencies are reformed. State Financial Inspection ,and from
October 2015 State Audit Office is one of such agencies, whose activities assigned to ensuring financial and economic security of the State and realize the financial control of the financial assets of State and activity of disponents of budget funds
Superfast Cooling
Currently laser cooling schemes are fundamentally based on the weak coupling
regime. This requirement sets the trap frequency as an upper bound to the
cooling rate. In this work we present a numerical study that shows the
feasibility of cooling in the strong coupling regime which then allows cooling
rates that are faster than the trap frequency with state of the art
experimental parameters. The scheme we present can work for trapped atoms or
ions as well as mechanical oscillators. It can also cool medium size ions
chains close to the ground state.Comment: 5 pages 4 figure
Reforming backgrounds of the state financial inspection
Relevance of the topic. Financial and economy security of Ukraine is one of the most important elements of the national security of the State. The high level of financial and economy security allow to assist (promote) the stable functioning of the economy, ensuring favorable financial conditions for the activity subject’s economy managements and creating positive financial climate in general. To ensure that directed activity of several government agencies. For today lots of these agencies are reformed. State Financial Inspection ,and from
October 2015 State Audit Office is one of such agencies, whose activities assigned to ensuring financial and economic security of the State and realize the financial control of the financial assets of State and activity of disponents of budget funds
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