共查询到20条相似文献,搜索用时 31 毫秒
1.
We give the formulas of two-pion Hanbury-Brown-Twiss (HBT) correlation function for a partially coherent evolution pion-emitting source,using quantum probability amplitudes in a path-integral formalism.The multiple scattering of the particles in the source is taken into consideration based on Glauber scattering theory.Two-pion interferometry with effects of the multiple scattering and source collective expansion is examined for a partially coherent source of hadronic gas with a finite baryon density and evolving hydrodynamically.We do not find observable effect of either the multiple scattering or the source collective expansion on HBT chaotic parameter. 相似文献
2.
We examine the two-pion Hanbury-Brown-Twiss (HBT) interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy. The source evolution is described by relativistic hydrodynamics with three kinds of equations of state for chemical equilibrium (CE), chemical freeze-out (CFO), and partial chemical equilibrium (PCE) models, respectively. We investigate the effects of particle decay, multiple scattering, and source collective expansion on the two-pion interferometry results. We find that the HBT radii of the evolution source for the CFO and PCE models are smaller than that for the CE model. The HBT lifetime for the CFO model is smaller than those for the PCE and CE models. The particle decay increases the HBT radius and lifetime while the source 相似文献
3.
We examine the two-pion Hanbury-Brown-Twiss (HBT) interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy. The source evolution is described by relativistic hydrodynamics with three kinds of equations of state for chemical equilibrium (CE), chemical freeze-out (CFO),and partial chemical equilibrium (PCE) models, respectively. We investigate the effects of particle decay,multiple scattering, and source collective expansion on the two-pion interferometry results. We find that the HBT radii of the evolution source for the CFO and PCE models are smaller than that for the CE model.The HBT lifetime for the CFO model is smaller than those for the PCE and CE models. The particle decay increases the HBT radius and lifetime while the source expansion decreases the HBT radius. The multiple scattering effect on the HBT results can be neglected based on our model calculations. 相似文献
4.
本文对Bjorken柱形夸克-胶子等离子体演化膨胀源进行了2π Hanbury-Brown-Twiss (HBT)干涉学分析.利用量子几率振幅的路径积分公式计算2π HBT关联函数并得到对膨胀和静态源的HBT半径. 研究发现,在冻结发射情况下的HBT半径要明显大于没有考虑多重散射吸收情况下的结果,源的膨胀速度导致HBT半径变小.对相变温度宽度为零的Bjorken柱形源,膨胀速度的影响要小于对应的球形源的结果. 相似文献
5.
The scattering of a partially coherent electromagnetic beam by a dielectric sphere is described. Two methods are presented: a coherent mode representation and a spherical harmonics expansion. In the case of a distant blackbody source, the coherent modes are plane waves and the scattered intensity is obtained by a convolution of the classical Mie results over the source surface. 相似文献
6.
应用量子路径积分的方法,分析了高能重离子碰撞产生的高重子数密度粒子发射源的2K和2π干涉学(hanbury Brown Twiss,HBT关联)。利用相对论流体动力学描述源的演化,采用的状态方程包含QGP到强子相的一级相变和对强子气体的体积修正。在2π关联的计算中考虑了激发态粒子衰变和多重散射效应,并将其HBT关联半径和寿命与传统热冻结模型的结果进行了对比。计算表明,早期化学冻结产生的K介子的HBT关联半径比2π关联的HBT关联半径小。激发态粒子的衰变使HBT关联半径和寿命增加,而多重散射对HBT关联的结果几乎没有影响。Using quantum path integral formulae, we examined the two kaon and two pion Hanbury Brown Twiss (HBT) interferometry for the particle emitting source with high baryon density. The evolution of the source is described by relativistic hydrodynamics. We use an equation of state of first order transition from QGP to hadronic phase and consider a volume correction for the hadronic gas. The two pion HBT results with effects of excited particle decay and multiple scattering were investigated and compared with those for conventional thermal freeze out (TFO) model. We found that the two kaon HBT radius was smaller than those of the two pion interferometry. The particle decay increases the HBT radius and lifetime, while the effect of multiple scattering on HBT results can be neglected. 相似文献
7.
LI ShuXia SUN PuNan & XIAO DeHang College of Physical Science Technology Heilongjiang University Harbin China 《中国科学:物理学 力学 天文学(英文版)》2011,(5)
We examine two-pion Bose-Einstein correlations for partially coherent particle-emitting sources within quantum statistical formalism, where the sources are treated as classical currents with chaotic and coherent components. The two-pion correlation functions of the partially coherent sources contain a phase which is sensitive to the asymmetry of the source emission function. We investigate the influence of source opacity and expansion in high energy heavy ion collisions on the phase by Monte Carlo calculati... 相似文献
8.
V.L. Kuzmin 《Optics Communications》2007,273(2):307-310
Based on an expansion of the Bethe-Salpeter equation in scattering orders a semi-analytic approach for simulation of coherent phenomena of multiple scattering in random media has been developed. We found that for scalar field the manifestation of these phenomena, observed as temporal field correlation function and coherent backscattering, are universal and well agreed with the results predicted by diffusion approximation. For the electromagnetic field the temporal correlation function and coherent backscattering are noticeably differ from those found for the scalar field, depending strongly on the scattering anisotropy. The obtained numerical results, for the first time to our knowledge, are compared directly with the known generalizations of the Milne solution. 相似文献
9.
本文对球形演化的夸克–胶子等离子体膨胀源进行了2π干涉学分析.夸克–胶子等离子体的演化由相对论流体力学和熵密度的物态方程描述,而2πHanbury-Brown-Twiss(HBT)关联函数由量子几率振幅的路径积分公式计算.研究结果表明,由2π干涉学得到的源的空间参量敏感地依赖于π介子发射源的相空间分布,源的膨胀速度导致HBT半径变小,并会改变HBT半径与冻结温度之间的关系. 相似文献
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12.
This paper describes a change in optical spectrum on propagation in free space for a particular class of spatially partially coherent fields emanating from a polychromatic secondary source. A rectangular opening aperture in an opaque screen, illuminated with an extended incoherent polychromatic primary source, works as the secondary source. The spectral change is explored in detail theoretically and experimentally in association with spatial coherence in the secondary source as well as dispersive diffraction by the secondary source. The peak shift of the spectrum is associated with the coherence area for characterizing the secondary source. The peak shift becomes maximum if the secondary source is spatially coherent, but no shift occurs if the secondary source is spatially incoherent. 相似文献
13.
By using an expansion of the correlation function of partially coherent fields, the relation between the coherent components at the object and image planes has been analyzed. Also, in order to establish a one-to-one correspondence between these coherent components at both planes, a new expansion of the correlation function of the source at the object plane has been obtained. 相似文献
14.
Propagation and coherence properties of higher order partially coherent dark hollow beams in turbulence 总被引:3,自引:1,他引:2
Halil Tanyer Eyyubolu 《Optics & Laser Technology》2008,40(1):156-166
We formulate and evaluate in terms of graphical outputs, source and receiver plane expressions, the complex degree of coherence, beam size variation and power in bucket performance for higher order partially coherent dark hollow beams propagating in turbulent atmosphere. Our formulation is able to cover square, rectangular, circular, elliptical geometries for dark hollow and flat-topped beams in one single expression. From the graphical outputs of the receiver plane, it is observed that higher order partially coherent dark hollow beams will initially develop an outer ring around a central lobe, but will eventually evolve towards a Gaussian shape as the propagation distance is extended. It is further observed that stronger turbulence levels and greater partial coherence have similar effects on beam profile. During propagation, modulus of complex degree of coherence of partially coherent dark hollow beams appears to rise above that of the source plane values, reaching as high as near unity. Beam size analysis shows that, among the types examined, (nearly) flat-topped beam experiences the least beam expansion. Power in bucket analysis indicates that lowest order square fully coherent dark beam offers the best power capturing. 相似文献
15.
E. Ikonen 《Physics of Particles and Nuclei Letters》2011,8(9):1004-1006
Use of three-particle correlations provides a unique tool for studying partial coherence in relativistic heavy-ion collisions.
Here a theory is presented for multiple coherent source components of partially coherent pion radiation. Results are given
for the relative probabilities of emission of one, two, or three pions. The calculations on the relation between two- and
three-pion correlators give some evidence, when compared with available experimental data, for the existence of partial coherence
and multiple coherent components in heavy-ion collisions. 相似文献
16.
We investigate the effect of pump phase noise on the collective backscattering of light by a cold, collisionless atomic gas. We show that for a partially coherent pump field, the growth rate of the backscattered field is reduced relative to that for a coherent pump, but the backscattered intensity can be increased. Our results demonstrate that fluctuations and noise can play a counterintuitive role in nonlocally coupled many-body systems. 相似文献
17.
We previously demonstrated that Mie scattering of stationary partially coherent light by dielectric spheres generates coherence vortices. In this Letter, we demonstrate that a lattice of coherence vortices can be generated by Mie scattering of partially coherent electromagnetic waves by a system of three coplanar dielectric spheres. Spontaneous coherence-vortex creation and destruction is observed in our computer modeling of this system. 相似文献
18.
We have extended the exploration of microscopic dynamics of supercooled liquids to small wave numbers Q corresponding to the scale of intermediate range order, by developing a new experimental approach for precise data correction for multiple scattering noise in inelastic coherent neutron scattering. Our results in supercooled Ca0.4K0.6(NO3)(1.4) reveal the first direct experimental evidence, after a decade of controversy, that the so-called picosecond process around the glass transition corresponds to a predicted first, faster stage of the structural relaxation. In addition, they show that this process takes the spatial form of fast heterogeneous collective flow of correlated groups of atoms. 相似文献
19.
Franco Gori Vittorio Bagini Massimo Santarsiero Fabrizio Frezza Giuseppe Schettini Giuseppe Schirripa Spagnolo 《Optical Review》1994,1(2):143-145
We present coherent and partially coherent beams that exhibit transverse pattern expansion and rotation upon free propagation. Coherent twisting beams may be generated by a suitable superposition of Laguerre-Gauss modes, while a model for partially coherent twisting beams is given by a continuous incoherent superposition of lowest order modes. 相似文献