Wednesday, March 7, 2018

180303 Topological quantum phase transitions in Haldane spin chains

Title:
Topological quantum phase transitions in Haldane spin chains


Time:
03/03 (Sat.) 11 am PDT, 12 pm MDT, 1 pm CDT, 2 pm EDT
03/04 (Sun.) 2 am Taiwan


Abstract:
I will give some introductions to the 2016 Nobel price in physics, particular in the Topological phases and Topological quantum phase transitions in one-dimensional quantum spin chains. In quantum mechanics, the volume of the spin can only be half-odd-integer (S=1/2, 3/2, 5/2,...) or integer. (S=1,2,3,...) When the spins are aligned into a 1D array, by their spin-spin interactions, the behaviors are very different between half-odd-integer spin chain and integer spin chain. This is the so-called "Haldane conjecture" which was made by D.Haldane in 1980's. Nowadays we further know the odd-integer (S=1,3,5,...) spin chains belong to the Symmetry-Protected-Topological phase, and the even-integer (S=2,4,6,...) spin chains are connected with trivial phases. Haldane won the Nobel price in 2016 for his contributions to ​the ​ theoretical discoveries of topological phase transitions and topological phases of matter.

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