Upcoming Seminars

Date/Place Jun. 12th (Tue.) 15:30-16:30 / H711
Name Motoi Endo (KEK)
Title Revisiting TeV-scale SUSY
Abstract Although no new particles have been discovered in the LHC experiments, SUSY has been one of the most attractive scenarios of physics beyond the SM. In this talk, we overview the status and prospects of SUSY in a TeV scale. In particular, we will show that some of the flavor anomalies are (still) explained well by the scenarios without conflicting with the LHC and other constraints.


Date/Place Jun. 19th (Tue.) 15:30-16:30 / H711
Name Koji Umemoto (YITP)
Title Entanglement of Purification in Holography and its Multipartite Generalization
Abstract It has been more than 10 years since a connection between quantum information theory and quantum gravity was found in the context of AdS/ CFT correspondence. There it was conjectured that the entanglement entropy in holographic CFTs is equal to the minimal geometrical area of certain codimention-2 surfaces in the bulk AdS. This is now called Ryu- Takayanagi or holographic entanglement entropy formula and has passed substantial tests. Since the entanglement entropy represents an amount of quantum entanglement for pure states, this formula motivate us to investigate the potential relationship between boundary entanglement and bulky geometry. However, one problem here is that one can not use the entanglement entropy as a measure of entanglement for mixed states: the entanglement entropy loose its meaning of “entanglement” for mixed states and becomes just a von Neumann entropy of considered subsystem. Such mixed states naturally appear in AdS/CFT e.g. when one considers bipartite subsystems on the boundary, or black hole geometry itself is also mixed. In this seminar, we talk about a generalization of the holographic entanglement entropy formula which is applicable for mixed states. We propose that the entanglement of purification, which is a generalization of entanglement entropy for mixed states capturing both quantum entanglement and classical correlations, has a gravitational counterpart expressed by a certain minimal area of codimension-2 surface in the entanglement wedge. We show that known properties of entanglement of purification are indeed satisfied by the conjectured holographic counterpart, and also give a heuristic explanation why this relation happens based on the tensor network description. On the other hand, another problem is that in multipartite systems (such as 3 qubits) we have to deal with multipartite entanglement to know the detailed structure of quantum states. Again the entanglement entropy can not be used for this purpose. Then we also generalize the holographic entanglement of purification conjecture to multipartite setups and test its validity. We define a multipartite generalization of entanglement of purification and that of holographic counterpart, and then prove their properties independently. We confirm that these two quantity indeed share all the properties we concerned. These agreements support the multipartite (including bipartite) holographic entanglement of purification conjecture.


Date/Place Jun. 22nd (Fri.) 12:10-13:10 / H711
Name Hermann Nicolai (Max Planck Institute)
Title The Conformal Standard Model
Abstract The Conformal Standard Model (CSM) is a minimal extension of the Standard Model of Particle Physics based on the assumed absence of large intermediate scales between the TeV scale and the Planck scale, which incorporates only right-chiral neutrinos and a new complex scalar in addition to the usual SM degrees of freedom, but no other features such as supersymmetric partners. In this talk I will present an overview and argue that all outstanding issues of particle physics proper can in principle be solved ‘in one go’ within this framework. The main testable prediction of the model is a new and almost sterile scalar boson that would manifest itself as a narrow resonance in the TeV region.


Date/Place Jul. 3th (Tue.) 15:30-16:30 / H711
Name Takao Suyama (KEK)
Title \theta=\pi in SU(N)/Z_N Theory
Abstract In SU(N) gauge theory, it is argued recently that there exists a "mixed anomaly" between the CP symmetry and the 1-form ZN symmetry at θ=π, and the anomaly matching requires CP to be spontaneously broken at θ=π if the system is in the confining phase. In this paper, we elaborate on this discussion by examining the large volume behavior of the partition functions of the SU(N)/ZN theory on T4 a la 't Hooft. The periodicity of the partition function in θ, which is not 2π due to fractional instanton numbers, suggests the presence of a phase transition at θ=π. We propose lattice simulations to study the distribution of the instanton number in SU(N)/ZN theories. A characteristic shape of the distribution is predicted when the system is in the confining phase. The measurements of the distribution may be useful in understanding the phase structure of the theory.


Past Seminars