48,391 research outputs found
New transformation of Wigner operator in phase space quantum mechanics for the two-mode entangled case
As a natural extension of Fan's paper (arXiv: 0903.1769vl [quant-ph]) by
employing the formula of operators' Weyl ordering expansion and the bipartite
entangled state representation we find new two-fold complex integration
transformation about the Wigner operator (in its entangled form) in phase space
quantum mechanics and its inverse transformation. In this way, some operator
ordering problems can be solved and the contents of phase space quantum
mechanics can be enriched.Comment: 8 pages, 0 figure
Entangled Husimi distribution and Complex Wavelet transformation
Based on the proceding Letter [Int. J. Theor. Phys. 48, 1539 (2009)], we
expand the relation between wavelet transformation and Husimi distribution
function to the entangled case. We find that the optical complex wavelet
transformation can be used to study the entangled Husimi distribution function
in phase space theory of quantum optics. We prove that the entangled Husimi
distribution function of a two-mode quantum state |phi> is just the modulus
square of the complex wavelet transform of exp{-(|eta|^2)/2} with phi(eta)being
the mother wavelet up to a Gaussian function.Comment: 7 page
Wigner functions of thermo number state, photon subtracted and added thermo vacuum state at finite temperature
Based on Takahashi-Umezawa thermo field dynamics and the order-invariance of
Weyl ordered operators under similar transformations, we present a new approach
to deriving the exact Wigner functions of thermo number state, photon
subtracted and added thermo vacuum state. We find that these Wigner functions
are related to the Gaussian-Laguerre type functions of temperature, whose
statistical properties are then analysed.Comment: 10 pages and 2 figure
Quantum mechanical photon-count formula derived by entangled state representation
By introducing the thermo entangled state representation, we derived four new
photocount distribution formulas for a given density operator of light field.
It is shown that these new formulas, which is convenient to calculate the
photocount, can be expressed as such integrations over Laguree-Gaussian
function with characteristic function, Wigner function, Q-function, and
P-function, respectively.Comment: 5 pages, no figur
Spontaneous Transport Barriers Quench Turbulent Resistivity in 2D MHD
This Letter identifies the physical mechanism for the quench of turbulent
resistivity in 2D MHD. Without an imposed, ordered magnetic field, a
multi-scale, blob-and-barrier structure of magnetic potential forms
spontaneously. Magnetic energy is concentrated in thin, linear barriers,
located at the interstices between blobs. The barriers quench the transport and
kinematic decay of magnetic energy. The local transport bifurcation underlying
barrier formation is linked to the inverse cascade of and
negative resistivity, which induce local bistability. For small scale forcing,
spontaneous layering of the magnetic potential occurs, with barriers located at
the interstices between layers. This structure is effectively a magnetic
staircase
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Hydrodynamic Analysis of Binary Immiscible Metallurgical Flow in a Novel Mixing Process: Rheomixing
This paper presents a hydrodynamic analysis of binary immiscible metallurgical flow by a numerical simulation of the rheomixing process. The concept of multi-controll is proposed for classifying complex processes and identifying individual processes in an immiscible alloy system in order to perform simulations. A brief review of fabrication methods for immiscible alloys is given, and fluid flow aspects of a novel fabrication method – rheomixing by twin-screw extruder (TSE) are analysed. Fundamental hydrodynamic micro-mechanisms in a TSE are simulated by a piecewise linear (PLIC) volume-of-fluid (VOF) method coupled with the continuum surface force (CFS) algorithm. This revealed that continuous reorientation in the TSE process could produce fine droplets and the best mixing efficiency. It is verified that TSE is a better mixing device than single screw extruder (SSE) and can achieve finer droplets. Numerical results show good qualitative agreement with experimental results. It is concluded that rheomixing by a TSE can be successfully employed for casting immiscible engineering alloys due to its unique characteristics of reorientation and surface renewal
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Numerical analysis of the hydrodynamic behaviour of immiscible metallic alloys in twin-screw rheomixing process
A numerical analysis by a VOF method is presented for studying the hydrodynamic mechanisms of the rheomixing process by a twin-screw extruder (TSE). The simplified flow field is established based on a systematic analysis of flow features of immiscible alloys in TSE rheomixing process. The studies focus on the fundamental microstructure mechanisms of rheological behaviour in shear-induced turbulent flows. It is noted that the microstructure of immiscible alloys in the mixing process is strongly influenced by the interaction between droplets, which is controlled by shearing forces, viscosity ratio, turbulence, and shearing time. The numerical results show a good qualitative agreement with the experimental results, and are useful for further optimisation design of prototypical rheomixing processes
The Radio and Gamma-Ray Luminosities of Blazars
Based on the -ray data of blazars in the third EGRET catalog and
radio data at 5 GHz, we studied the correlation between the radio and
-ray luminosities using two statistical methods. The first method was
the partial correlation analysis method, which indicates that there exist
correlations between the radio and -ray luminosities in both high and
low states as well as in the average case.
The second method involved a comparison of expected -ray luminosity
distribution with the observed data using the Kolmogorov--
Smirnov (KS) test. In the second method, we assumed that there is a
correlation between the radio and -ray luminosities and that the
-ray luminosity function is proportional to the radio luminosity
function. The KS test indicates that the expected gamma-ray luminosity
distributions are consistent with the observed data in a reasonable parameter
range. Finally, we used different -ray luminosity functions to estimate
the possible 'observed'
-ray luminosity distributions by GLAST.Comment: 8 pages, 4 figures, one table, PASJ, 53 (2001
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