Topological phases of matter is an active research area of condensed matter physics. Among vario us topics\, the bosonic symmetry protected topological (BSPT) states have attracted enormous theoretical interest in the last few years. BSPT states are bosonic analogs of topological insulators. The Haldane phase of spin- 1 chains is one famous example. I will talk about our recent proposal to r ealize two-dimensional BSPT states in the twisted bilayer graphene with st rong magnetic field\, as well as numerical simulations of the lattice mode l in various parameter regimes. The proposed BSPT state is a quantum spin Hall insulator with bosonic boundary modes only. The bosonic modes are spi n and charge collective excitations of electrons. The quantum phase transi tion between the topological and the trivial phases happens by closing the gap of bosonic modes in the bulk\, without closing the single particle ga p of electrons\, which is fundamentally different from all the well-known topological transitions in free fermion topological insulators. On the the ory side\, the phase transition is related to topics of deconfined critica lity and duality of (2+1)D conformal field theories. The theoretical\, num erical and experimental studies will deepen our understanding of quantum p hase transitions.

\n\n**THE RECEPTION WILL BE HELD AT 3:00PM IN ROOM 313**

\n DTSTART:20170216T203000Z LOCATION:Physics Building\, Room 204 SUMMARY:Bosonic Symmetry Protected Topological States: Theory\, Numerics\, and Experimental Platform END:VEVENT END:VCALENDAR