AdS(AdS, duality and Strings) semianr
Student No.:50
Time:Thursday 13:30-15:00, 2017-2-23~2017-7-13
Instructor:Babak Haghighat, Hai Lin, Wei Song, Qiang Wen, Jianfei Xu  
Place:Conference room 3, Floor 2, Jin Chun Yuan West Building
Starting Date:2017-2-23
Ending Date:2017-7-13



This is a weekly seminar of the string theory group at YMSC



Date: 2017-03-30        




Speaker: Shaokai Jian (IAS, THU)    



Time: 2017-03-30 13:30-15:00  



Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU     



Title: Solvable SYK models in higher dimensions: a new type of many-body localizationtransition



Abstract: Many aspects of many-body localization (MBL) transitions remain elusive so far. Here, we propose a higher-dimensional generalization of the Sachdev-Ye-Kitaev (SYK) model and show that itexhibits an MBL transition. The model on a bipartite lattice has N Majorana fermions with SYKinteractions on each site of A-sublattice and M free Majorana fermions on each site of B-sublattice.For rM/N <rc=1, it describes a diffusive metal exhibiting maximal chaos. Remarkably, its diffusive constant D vanishes as rrc [D(rc −r)1/2], implying a dynamical transition to an MBL phase.It is further supported by numerical calculations of level statistics which changes from Wigner-Dyson(r<rc) to Poisson (r>rc) distributions. Note that no subdiffusive phase intervenes between diffusive and MBL phases. Moreover, the critical exponent ν=0, violating the Harris criterion. Ourhigher-dimensional SYK model may provide a promising arena to explore exotic MBL transitions.




Date: 2017-03-23         


Speaker: Dmitry Polyakov (Sichuan U.)    


Time: 2017-03-23 13:30-15:00   


Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU    


Title: An Analytic Formula for Numbers of Restricted Partitions from Conformal Field Theory







Date: 2017-03-15         


Speaker: Hossein Yavartanoo (ITP)    


Time: 2017-03-15 13:30-15:00  



Place: Conf. room 4, Floor 2, Jin Chun Yuan West B., THU    


Title: Combing the Horizon Fluff: Logarithmic corrections to black hole entropy from horizon fluff proposal


Abstract: According to the horizon fluff proposal microstates of a generic black hole is a certain subset ofnear horizon soft hairs that cannot be extended to beyond the near horizon region. Previously we have discussed how horizon fluff proposal works for AdS3 black holes. In this talk I will clarify furtherthe picture for BTZ black holes and their microstates arising from the proposal. In particular, I will show that BTZ black hole microstates are in general among the set of conic defects or theirVirasoro descendants and that a BTZ black hole may be viewed as a condensate, solitonicstates, of AdS3 particles. I will also provide canonical and microcanonical descriptions of statisticalmechanical system associated with BTZ black holes and their microstates and that how thetwo are related. Using the latter and as a further non-trivial check, we will se how the horizon fluffproposal precisely reproduces the logarithmic corrections to the BTZ entropy, as expected fromthe logarithmic corrections to the Cardy formula.




Date: 2017-03-16        



Speaker: Zhibin Li (IHEP)    


Time: 2017-03-16 13:30-15:00  


Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU     



Title: Mutual information of two intervals in AdS3/CFT2



Abstract: We consider the (Renyi) mutual information of two intervals in AdS3/CFT2. In CFT side we calculate the RMI and MI from the OPE of twist operators. For the dual AdS we need to use the partition function of handlebody. We also consider the contributions of W3 and W4 operators.





Date: 2017-03-09       


Speaker: Hui-Huang Chen (IHEP)    


Time: 2017-03-09 13:30-15:00  


Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU    


Title: γ-deformed ABJM theory and Y-system


Abstract: In this talk I will show some of the integrable aspects of the planar γ-deformed ABJM theory and propose the twisted asymptotic Bethe ansatz equations. A more general method through a twisted generating functional is discussed, based on which, the asymptotic large L solution of Y-system is modified in order to match the asymptotic Bethe ansatz equations. Several applications of our method in the sl(2)-like sector and some important examples in β-deformed ABJM are presented as well.



Date: 2017-03-02         

Speaker: Ling-Yan Hung (Fudan U.)    


Time: 2017-03-02 13:30-15:00  


Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU    


Title: Exploring the tensor network/ ads correspondence -- bulk operator reconstruction


Abstract: I will discuss some recent developments in exploring the similarities between tensor networks and the ads/cft correspondence. In this talk, we will focus particularly on the bulk operator reconstruction from the boundary. We find some very interesting parallels between the tensor network and the HKLL formula in the ads/cft dictionary. We also discuss the realization of global symmetries in the form of gauge symmetries in the tensor network bulk. We illustrate some of these ideas using the p-adic ads/cft as a toy example.




Date: 2017-02-23  


Speaker: Mei Huang (IHEP)   


Time: 2017-02-23 13:30-15:00  


Place: Conf. room 3, Floor 2, Jin Chun Yuan West B., THU   


Title: Dynamical holographic QCD model