上海交通大学物理系.ppt

随机相互作用下原子核结构 研究的新进展,上海交通大学物理系,赵玉民,提纲,随机相互作用原子核低激发态主要结果 最近其他研究组几个工作 我们最近的工作 展望,Part I,随机相互作用下原子核的 规则结构的主要结果,Wigner introduced Gaussian orthogonal ensemble of random matrices (GOE) in understanding the spacings of energy levels observed in resonances of slow neutron scattering on heavy nuclei. Ref: Ann. Math. 67, 325 (1958) 1970s French, Wong, Bohigas, Flores introduced two-body random ensemble (TBRE) Ref: Rev. Mod. Phys. 53, 385 (1981); Phys. Rep. 299, (1998); Phys. Rep. 347, 223 (2001). Original References: J. B. French and S.S.M.Wong, Phys. Lett. B33, 449(1970); O. Bohigas and J. Flores, Phys. Lett. B34, 261 (1970). Other applications: complicated systems (e.g., quantum chaos),Two-body Random ensemble (TBRE),What does 0 g.s. dominance mean ? In 1998, Johnson, Bertsch, and Dean discovered that spin parity =0+ ground state dominance can be obtained by using random two-body interactions. This result is called the 0 g.s. dominance. Similar phenomenon was found in other systems, say, sd-boson systems. C. W. Johnson et al., PRL80, 2749 (1998); R. Bijker et al., PRL84, 420 (2000); L. Kaplan et al., PRB65, 235120 (2002).,One usually choose Gaussian distribution for two-body random interactions There are some people who use other distributions, for example, A uniform distribution between -1 and 1. For our study, it is found that these different distribution present similar statistics.,Two-body random ensemble（）,A Simple example,Where this result is interesting?,Available Results,Empircal method Zhao off-diagonal matrix elements for I=0 states Drozdz et al. (2001) Highest symmetry &Time Reveral Otsuka&Shimizu(2004-2007) Spectral Radius Papenbrock & Weidenmueller (2004-2007) Semi-empirical formula Yoshinaga, Arima and Zhao(2006-2007),References after Johnson, Bertsch and Dean,R. Bijker, A. Frank, and S. Pittel, Phys. Rev. C60, 021302(1999); D. Mulhall, A. Volya, and V. Zelevinsky, Phys. Rev. Lett.85, 4016(2000); Nucl. Phys. A682, 229c(2001); V. Zelevinsky, D. Mulhall, and A. Volya, Yad. Fiz. 64, 579(2001); D. Kusnezov, Phys. Rev. Lett. 85, 3773(2000); ibid. 87, 029202 (2001); L. Kaplan and T. Papenbrock, Phys. Rev. Lett. 84, 4553(2000); R.Bijker and A.Frank, Phys. Rev. Lett.87, 029201(2001); S. Drozdz and M. Wojcik, Physica A301, 291(2001); L. Kaplan, T. Papenbrock, and C. W. Johnson, Phys. Rev. C63, 014307(2001); R. Bijker and A. Frank, Phys. Rev. C64, (R)061303(2001); R. Bijker and A. Frank, Phys. Rev. C65, 044316(2002); P.H-T.Chau, A. Frank, N.A.Smirnova, and P.V.Isacker, Phys. Rev. C66, 061301 (2002); L. Kaplan, T.Papenbrock, and G.F. Bertsch, Phys. Rev. B65, 235120(2002); L. F. Santos, D. Kusnezov, and P. Jacquod, Phys. Lett. B537, 62(2002); T. Papenbrock and H. A. Weidenmueller, Phys. Rev. Lett. 93, 132503 (2004); T. Papenbrock and H. A. Weidenmueller, Phys. Rev. C 73 014311 (2006); Y.M. Zhao and A. Arima, Phys. Rev.C64, (R)041301(2001); A. Arima, N. Yoshinaga, and Y.M. Zhao, Eur.J.Phys. A13, 105(2002); N. Yoshinaga, A. Arima, and Y.M. Zhao, J. Phys. A35, 8575(2002); Y. M. Zhao, A. Arima, and N. Yoshinaga, Phys. Rev.C66, 034302(2002); Y. M. Zhao, A. Arima, and N. Yoshinaga, Phys. Rev. C66, 064322(2002); Y.M.Zhao, A. Arima, N. Yoshinaga, Phys.Rev.C66, 064323 (2002); Y. M. Zhao, S. Pittel, R. Bijker, A. Frank, and A. Arima, Phys. Rev. C66, R41301 (2002); Y. M. Zhao, A. Arima, G. J. Ginocchio, and N. Yoshinaga, Phys. Rev. C66,034320(2003); Y. M. Zhao, A. Arima, N. Yoshinga, Phys. Rev. C68, 14322 (2003); Y. M. Zhao, A. Arima, N. Shimizu, K. Ogawa, N. Yoshinaga, O. Scholten, Phys. Rev. C70, 054322 (2004); Y.M.Zhao, A. Arima, K. Ogawa, Phys. Rev. C71, 017304 (2005); Y. M. Zhao, A. Arima, N. Yoshida, K. Ogawa, N. Yoshinaga, and V.K.B.Kota , Phys. Rev. C72, 064314 (2005); N. Yoshinaga, A. Arima, and Y. M. Zhao, Phys. Rev. C73, 017303 (2006); Y. M. Zhao, J. L. Ping, A. Arima, Phys. Rev. C76, 054318 (2007); J. J. Shen, Y. M. Zhao, A. Arima, N. Yoshinaga, Physic. Rev. C77, 054312 (2008); J. J. Shen, A. Arima, Y. M. Zhao, N. Yoshinagan, Phys. Rev. C78, in press (2008); etc. Review paper： Y.M. Zhao , A. Arima, and N. Yoshinaga, Physics Reports 400, 1 (2004).,Phenomenological method by our group (Zhao, Arima and Yoshinaga): reasonably applicable to all systems Mean field method by Bijker and Frank group: sd, sp boson systems (Kusnezov also considered sp bosons in a similar way) Geometric method suggested by Chau, Frank, Smirnova, and Isacker goes along the same line of our method (provided a foundation of our method for simple systems in which eigenvalues are in linear combinations of two-body interactions).,Applications of our method to realistic systems,Spin Imax Ground state probabilities,By using our phenomenological method, one can trace back what interactions, not only monopole pairing interaction but also some other terms with specific features, are responsible for 0 g.s. dominance. We understand that the Imax g.s. probability comes from the Jmax pairing interaction for single-j shell (also for bosons). The phenomenology also predicts spin I g.s. probabilities well. On the other hand, the reason of success of this method is not fully understood at a deep level, i.e., starting from a fundamental symmetry. Bijker-Frank mean field applies very well to sp bosons and reasonably well to sd bosons. Geometry method Chau, Frank, Sminova and Isacker is applicable to simple systems.,Summary of understanding of the 0 g.s. dominance,Time reversal invariance Zuker et al. (2002); Time reversal invariance? Bijker off-diagonal matrix elements for I=0 states Drozdz et al. (2001), Highest symmetry hypothesis Otsuka&Shimizu(2004), Spectral Radius by Papenbrock & Weidenmueller (2004-2006) Semi-empirical formula by Yoshinaga, Arima and Zhao(2006).,Other works,2. Energy centroids of spin I states under random interactions,Other works on energy centroids,Mulhall, Volya, and Zelevinsky, PRL(2000) Kota, PRC(2005) YMZ, AA, Yoshida, Ogawa, Yoshinaga, and Kota, PRC(2005) YMZ, AA, and Ogawa PRC(2005),3. Collective motion in the presence of random interactions,Collectivity in the IBM under random interactions,Taken from PRC62,014303(2000), by R. Bijker and A. Frank,Taken from PRL84,420(2000), by R. Bijker and A. Frank,Shell model: Horoi, Zelevinsky, Volya, PRC, PRL; Velazquez, Zuker, Frank, PRC; Dean et al., PRC; IBM: Kusnezov, Casten, et al., PRL; Geometric model: Zhang, Casten, PRC;,Other works,Part II. Recent efforts on nuclei under random interactions,Recent efforts on 0 g.s. dominance,Highest symmetry &Time Reveral Otsuka & Shimizu(2004-2007) Spectral Radius Papenbrock & Weidenmueller (2004-2007) Semi-empirical formula Yoshinaga, Arima and Zhao(2006-2007),YMZ, Pittel, Bijker, Frank, and AA, PRC66, 041301 (2002). (By using usual SD pairs) YMZ, J. L. Ping, and AA, PRC76, 054318 (2007). (By using symmetry dictated pairs-FDSM) Calvin W. Johnson, Hai Ah Nam, PRC75, 047305 (2007). Shell model calculations,集体运动模式,(A) Both protons and neutrons are in the shell which corresponds to nuclei with both proton number Z and neutron number N 40; (B) Protons in the shell and neutrons in the shell which correspond to nuclei with Z40 and N50; (C) Both protons and neutrons are in the shell which correspond to nuclei with Z and N82; (D) Protons in the shell and neutrons in the shell which correspond to nuclei with Z50 and N82.,随机相互作用下宇称分布规律,The worst case is P(+)=67%，the best case is 99.9%。On average P(+)86%。 No counter example has been found so far！,Physical Review C, in press,Part III. 我们最近的工作,我们最近的工作(1)：矩阵的本征值问题 (最低本征值和所有本征值),“Lowest Eigenvalues of Random Hamiltonians”(2008). J. J. Shen, Y. M. Zhao, A. Arima, and N. Yoshinaga, Physical Review C77, 054312. “Strong Linear Correlation Between Eigenvalues and Diagonal Matrix elements”, J. J. Shen, A. Arima, Y. M. Zhao, and N. Yoshinaga, Physical Review C(2008). N. Yoshinaga, A. Arima, J. J. Shen, and Y. M. Zhao, “Functional Dependence of eignevalues an