INVITADO:Sanjoy Sarker 
University of Alabama,US

Date:8 de mayo, 2013 
Time:14:30 
Place:3rd floor seminar lecture room. Dpt. Física Teórica I. Facultad de Ciencias Físicas UCM.

ABSTRACT.

 The"origin"of"the"highly"unusual"behavior"of"a cuprate"superconductor"is thought"to"be"due"to"its"proximity"to"the"Mott"insulator."Anderson argued"quite"early"that"spin"structure"of"the"doped"region"is"intimately connected"to"that"of"the"insulator."However,"attempts"to construct"a"theory"based"on"such a"connection"have"run"into"serious difficulties."I"will"discuss"some"recent"progress"made"in"this direction."Specifically,"we"have"derived"a"renormalized"Hamiltonian"from the"parent"tZJ"model,"which"is"charaterized"by"a"spin"gap. The"model"is"analyzed"by"continuing"the"known"spin"states"from"the insulator,"which"constraints"the"theory."This"leads"to"the"correct"phase diagram:"a"strange"metal,"a"pseudogap"metal"and"a"dZwave" superconductor. These"results"follow"directly" from"the"symmetry"of"the" known valenceZbond""vacuum""which"is"continued"from"half"filling."Not" much calculation"is"needed."Additionally,"the"twoZdimensional"nature"of" the metallic"state"emerges"from"the"theory.