4,408 research outputs found
Critical point of QCD from lattice simulations in the canonical ensemble
A canonical ensemble algorithm is employed to study the phase diagram of QCD using lattice simulations. We lock in the desired quark number sector
using an exact Fourier transform of the fermion determinant. We scan the phase
space below and look for an S-shape structure in the chemical potential,
which signals the coexistence phase of a first order phase transition in finite
volume. Applying Maxwell construction, we determine the boundaries of the
coexistence phase at three temperatures and extrapolate them to locate the
critical point. Using an improved gauge action and improved Wilson fermions on
lattices with a spatial extent of 1.8 \fm and quark masses close to that of
the strange, we find the critical point at and baryon
chemical potential .Comment: 5 pages, 7 figures, references added, published versio
Finite density phase transition of QCD with and using canonical ensemble method
In a progress toward searching for the QCD critical point, we study the
finite density phase transition of and 2 lattice QCD at finite
temperature with the canonical ensemble approach. We develop a winding number
expansion method to accurately project out the particle number from the fermion
determinant which greatly extends the applicable range of baryon number sectors
to make the study feasible. Our lattice simulation was carried out with the
clover fermions and improved gauge action. For a given temperature, we
calculate the baryon chemical potential from the canonical approach to look for
the mixed phase as a signal for the first order phase transition. In the case
of , we observe an "S-shape" structure in the chemical potential-density
plane due to the surface tension of the mixed phase in a finite volume which is
a signal for the first order phase transition. We use the Maxwell construction
to determine the phase boundaries for three temperatures below . The
intersecting point of the two extrapolated boundaries turns out to be at the
expected first order transition point at with . This serves as a
check for our method of identifying the critical point. We also studied the
case, but do not see a signal of the mixed phase for temperature as
low as 0.83 .Comment: 28 pages, 11 figures,references added, final versio
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A new understanding of El Niño's impact over East Asia: dominance of the ENSO combination mode
Previous studies have shown that the Indo-Pacific atmospheric response to ENSO comprises two dominant modes of variability: a meridionally quasi-symmetric response (independent from the annual cycle) and an anti-symmetric response (arising from the nonlinear atmospheric interaction between ENSO variability and the annual cycle), referred to as the combination mode (C-Mode). This study demonstrates that the direct El Niño signal over the tropics is confined to the equatorial region and has no significant impact on the atmospheric response over East Asia. The El Niño-associated equatorial anomalies can be expanded towards off-equatorial regions by the C-Mode through ENSO’s interaction with the annual cycle. The C-Mode is the prime driver for the development of an anomalous low-level anticyclone over the western North Pacific (WNP) during the El Niño decay phase, which usually transports more moisture to East Asia and thereby causes more precipitation over southern China. We use an Atmospheric General Circulation Model that well reproduces the WNP anticyclonic anomalies when both El Niño sea surface temperature (SST) anomalies as well as the SST annual cycle are prescribed as boundary conditions. However, no significant WNP anticyclonic circulation anomaly appears during the El Niño decay phase when excluding the SST annual cycle. Our analyses of observational data and model experiments suggest that the annual cycle plays a key role in the East Asian climate anomalies associated with El Niño through their nonlinear atmospheric interaction. Hence, a realistic simulation of the annual cycle is crucial in order to correctly capture the ENSO-associated climate anomalies over East Asia
Stability of Strutinsky Shell Correction Energy in Relativistic Mean Field Theory
The single-particle spectrum obtained from the relativistic mean field (RMF)
theory is used to extract the shell correction energy with the Strutinsky
method. Considering the delicate balance between the plateau condition in the
Strutinsky smoothing procedure and the convergence for the total binding
energy, the proper space sizes used in solving the RMF equations are
investigated in detail by taking 208Pb as an example. With the proper space
sizes, almost the same shell correction energies are obtained by solving the
RMF equations either on basis space or in coordinate space.Comment: 9 pages, 4 figure
Involving Low-Pressure Plasma for Surface Pre-Treatment and Post Print Sintering of Silver Tracks on Polymer Substrates
A method of production conductive silver tracks on thermally sensitive polymer (BOPP) was offered,
involving plasma for preprint polymer surface activation to enable better adhesion properties and postprint
selective etching to reduce amounts of polymer and raise electroconductivity. Inkjet, spin coating,
and roll-blade coating were the methods of application of silver nanoparticle inks. We report to achieve two
magnitudes lower sheet resistance of silver thin film with no effect on polymer substrate. This method with
little modification could be adopted for production of flexible electronics on highly thermally sensitive polymers.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3539
Non-Abelian Medium Effects in Quark-Gluon Plasma
Based on the kinetic theory, the non-Abelian medium property of hot
Quark-Gluon Plasma is investigated. The nonlinearity of the plasma comes from
two aspects: The nonlinear wave-wave interaction and self-interaction of color
field. The non-Abelian color permittivity is obtained by expanding the kinetic
equations to third order. As an application, the nonlinear Landau damping rate
and the nonlinear eigenfrequency shift are calculated in the longwave length
limit.Comment: 12 pages(Revtex), no figure
Symmetry breaking and manipulation of nonlinear optical modes in an asymmetric double-channel waveguide
We study light-beam propagation in a nonlinear coupler with an asymmetric
double-channel waveguide and derive various analytical forms of optical modes.
The results show that the symmetry-preserving modes in a symmetric
double-channel waveguide are deformed due to the asymmetry of the two-channel
waveguide, yet such a coupler supports the symmetry-breaking modes. The
dispersion relations reveal that the system with self-focusing nonlinear
response supports the degenerate modes, while for self-defocusingmedium the
degenerate modes do not exist. Furthermore, nonlinear manipulation is
investigated by launching optical modes supported in double-channel waveguide
into a nonlinear uniform medium.Comment: 10 page
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The annual-cycle modulation of meridional asymmetry in ENSO’s atmospheric response and its dependence on ENSO zonal structure
Previous studies documented that a distinct southward shift of central-Pacific low-level wind anomalies occurring during the ENSO decaying phase, is caused by an interaction between the Western Pacific annual cycle and El Niño-Southern Oscillation (ENSO) variability. The present study finds that the meridional movement of the central-Pacific wind anomalies appears only during traditional Eastern-Pacific (or EP) El Niño events rather than in Central-Pacific (CP) El Niño events in which sea surface temperature (SST) anomalies are confined to the central Pacific. The zonal structure of ENSO-related SST anomalies therefore has an important effect on meridional asymmetry in the associated atmospheric response and its modulation by the annual cycle. In contrast to EP El Niño events, the SST anomalies of CP El Niño events extend further west towards to the warm pool region with its climatological warm SSTs. In the warm pool region, relatively small SST anomalies thus are able to excite convection anomalies on both sides of the equator, even with a meridionally asymmetric SST background state. Therefore, almost meridionally symmetric precipitation and wind anomalies are observed over the central Pacific during the decaying phase of CP El Niño events. The SST anomaly pattern of La Niña events is similar to CP El Niño events with a reversed sign. Accordingly, no distinct southward displacement of the atmospheric response occurs over the central Pacific during the La Niña decaying phase. These results have important implications for ENSO climate impacts over East Asia, since the anomalous low-level anticyclone over the western North Pacific is an integral part of the annual cycle-modulated ENSO response
A Note on Normal Forms of Quantum States and Separability
We study the normal form of multipartite density matrices. It is shown that
the correlation matrix (CM) separability criterion can be improved from the
normal form we obtained under filtering transformations. Based on CM criterion
the entanglement witness is further constructed in terms of local orthogonal
observables for both bipartite and multipartite systems.Comment: 8 page
On Estimation of Fully Entangled Fraction
We study the fully entangled fraction (FEF) of arbitrary mixed states. New
upper bounds of FEF are derived. These upper bounds make complements on the
estimation of the value of FEF. For weakly mixed quantum states, an upper bound
is shown to be very tight to the exact value of FEF.Comment: 8 pages, 2 figure
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