摘要：
We investigate the effect of virtual photon processes (due to the antirotating terms in the Hamiltonian) on the time-dependent physical spectrum emitted by a two-level atom interacting with a single-mode quantized field in a perfect cavity. By means of a Heisenberg operator perturbative technique, a generalized emission spectrum is obtained which includes a contribution from the phase-dependent quantum interference between the real and virtual photons. The spectrum is phase sensitive. The effects of different statistics of the initial cavity mode are reported. For the cavity mode in a coherent state, one of the sidebands in the atomic emission spectrum can be reduced whilst the other can be enhanced due to the virtual photon transitions. The effect can be significant, and may be detected using a highly excited Rydberg atom in a microwave cavity with a high quality factor.
作者机构：
[胡响明; 汪德新] Institute of Applied Physics, Huazhong Normal University, Wuhan 430070, China;Department of Physics, Huazhong Normal University, Wuhan 430070, China
通讯机构：
Institute of Applied Physics, Huazhong Normal University, China
作者机构：
[胡响明; 彭金生] Institute of Applied Physics, Huazhong Normal University, Wuhan 430070, China;Department of Physics, Huazhong Normal University, Wuhan 430070, China
通讯机构：
Institute of Applied Physics, Huazhong Normal University, China
摘要：
A spectral representation for two-point Green function for arbitrary composite field operators is derived in Thermo Field Dynamics (;TFD). The application to two-to-two scattering at finite temperature shows that the corresponding cross section is of the form sigma=sigma(d)-sigma(i) for two bosons or two fermions, which is similar to the decay rate Gamma=Gamma(d)-Gamma(i) for single boson. The cross section sigma(d) for the scattering process and sigma(i) for the corresponding inverse process determine the rate of approaching to equilibrium of the particle distribution function.
期刊：
EUROPEAN PHYSICAL JOURNAL A,1997年358(3):337-351 ISSN：1434-6001
通讯作者：
Adamovich, MI
作者机构：
INST HIGH ENERGY PHYS,ALMATY,KAZAKHSTAN.;ACAD SINICA,INST HIGH ENERGY PHYS,BEIJING,PEOPLES R CHINA.;PANJAB UNIV,DEPT PHYS,CHANDIGARH 160014,INDIA.;HUNAN EDUC INST,DEPT PHYS,CHANGSHA,PEOPLES R CHINA.;JOINT INST NUCL RES,LAB COMP TECH,DUBNA,RUSSIA.
摘要：
Complex analysis of Gold interaction with photoemulsion nuclei at 10.7 GeV/nucleon has been performed. The data obtained were compared with a modified FRITIOF model which allowance is made for exitation of nuclear residuals (after interaction). A comparison was also made with cascade-evaporation model. Experimental data contradict the CEM supposition of fast resonance decay and complete cascading. The modified FRITIOF model fairly well reproduces experimental observations. According to the model the production mechanism of charged particles must remain unchangable in the 4-200 GeV/n energy range.
期刊：
Chinese Astronomy and Astrophysics,1997年21(4):405-414 ISSN：0275-1062
通讯作者：
Liu, X.-Y.
作者机构：
[YangPi-bo; LiuXiao-yong; YangLan-tian] Institute of Astrophysics, Central China Normal University, Wuhan, 430079, China;[ChenShao-li] Wuhan College of Textile Industry, Wuhan, China
通讯机构：
[Liu, X.-Y.] I;Institute of Astrophysics, Central China Normal University, China
摘要：
Considering nonthermal e±-pair production, this paper is focused on the radial structure of hot one-temperature accretion flows with advection under the condition of small viscous parameter (α = 0.1) and low mass-accretion rates. Self-similar relations of hot flow with advection have been adopted. The authors have used a scheme, in which the two regions of accretion flow are calculated separately and then joined together. Some typical features of hot flow with advection have been confirmed, and several new results obtained: there exists a critical radius rcr; the local cooling rate is inversely proportional to the square of the mass of the central object; the e±-pair process affects significantly the radiation of hot flows with advection.
作者机构：
Department of Physics, Central China Normal University, Wuhan, China;Department of Solid State Electronics, Huazhong University of Science and Techndogy, Wuhan, China;[Li, YP] Department of Physics, University of Science and Technology of China, Hefei, China;[Huang, XT; Qi, SR; Li, XJ] Department of Physics, Central China Normal University, Wuhan, China<&wdkj&>Department of Solid State Electronics, Huazhong University of Science and Techndogy, Wuhan, China
通讯机构：
[Huang, XT] C;CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN 430070,PEOPLES R CHINA.
摘要：
<正> Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy （STM） system, and the problems have attracted almost all STM scientists’ attention. In 1992, Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-
作者机构：
HIGH ENERGY PHYS INST, ALMA ATA, KAZAKHSTAN.;ACAD SINICA, INST HIGH ENERGY PHYS, BEIJING, PEOPLES R CHINA.;INST GRAVIATAT & SPACE RES, BUCHAREST, ROMANIA.;PANJAB UNIV, DEPT PHYS, CHANDIGARH 160014, INDIA.;HUNAN EDUC INST, DEPT PHYS, CHANGSHA, HUNAN, PEOPLES R CHINA.
摘要：
Results on charged particle multiplicities, densities and fluctuations from central Pb+Pb interactions at 158 A GeV are presented and discussed. (C) 1997 Elsevier Science B.V.
期刊：
EUROPEAN PHYSICAL JOURNAL C,1997年76(4):659-663 ISSN：1434-6044
通讯作者：
Adamovich, MI
作者机构：
PN Lebedev Phys Inst, Moscow 117924, Russia.;Inst High Energy Phys, KZ-480082 Alma Ata 82, Kazakhstan.;Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China.;Inst Gravitat & Space Res, Bucharest, Romania.;Panjab Univ, Dept Phys, Chandigarh 160014, India.
摘要：
The anomalous behavior of 2-dimensional scaled factorial moments for charged hadrons in nucleus-nucleus collisions is studied in some detail using both mini-bias and central collision data of O-16- and Au-197-Em interactions from EMU01 experiment. The analysis is carried out in terms of Hurst exponents, suggesting the necessity of different partitions in pseudo-rapidity and azimuthal angle. The results can be interpreted tentatively as due to the superposition effect in nucleus-nucleus collisions.
期刊：
EUROPEAN PHYSICAL JOURNAL A,1997年359(3):277-290 ISSN：1434-6001
通讯作者：
Adamovich, MI
作者机构：
ACAD SINICA, INST HIGH ENERGY PHYS, BEIJING, PEOPLES R CHINA.;INST GRAVITAT & SPACE RES, BUCHAREST, ROMANIA.;PANJAB UNIV, DEPT PHYS, CHANDIGARH 160014, INDIA.;HUNAN EDUC INST, DEPT PHYS, CHANGSHA, HUNAN, PEOPLES R CHINA.;JOINT NUCL RES INST, LAB COMP TECHN, DUBNA, RUSSIA.
通讯机构：
[Adamovich, MI] I;INST HIGH ENERGY PHYS, Alma Ata, KAZAKHSTAN.
摘要：
Recent results from the EMU-01/12 collaboration are presented for 10.7 GeV/nucleon gold nuclei interactions in emulsion. The distributions of ''bound'' charge (Z(bound;)Z(b3)), multiplicity distributions, fragment correlations and fluctuations are discussed. The data are compared to similar results obtained on the ALADIN setup at 600 MeV/nucleon. It is shown that multifragmentation of gold nuclei at high and intermediate energies has common features. It is also obtained that the IMFs have reduced multiplicity at high energies. The data are analyzed within the scope of the statistical model of multifragmentation. This model requires the following predetermined model ingredients: mass, charge and excitation energy of nuclear residuals. The simple estimation method of these characteristics is proposed in the framework of the Glauber approach. It is shown that the multifragmentation model reproduces qualitatively the present data. A dramatic discrepancy between the predicted and experimental yield of two charged fragments is found. The evolution of transverse momentum of fragments as a function of Z(bound) is presented. It is shown that the model greatly underpredicts the transverse momentum of fragments. It is interpreted as evidence of a strong radial flow of spectator fragments.
