ELFT HÍRADÓ

[tcsaba <tcsaba AT eik.bme.hu>]

                   M E G H Í V Ó - I N V I T A T I O N

    Seminar Series of the Department of Theoretical Physics at the
           Budapest University of Technology and Economics


                            Gábor Halász
                        (Oxford University)

   Hole dynamics in exactly solvable gapped and gapless spin liquids

We present a controlled microscopic study of hole dynamics in both a 
gapped and a gapless spin liquid. Our approach is complementary to 
previous phenomenological works as we introduce mobile holes into the 
spin liquid ground state of the exactly solvable Kitaev honeycomb model. 
In the gapped phase of the model, we address the single-particle 
properties of individual holes (such as their particle statistics and 
hopping properties) and the multi-particle ground state at a finite 
density of holes. Our main result is that the holes possess internal 
degrees of freedom as they can bind the fractional excitations of the 
spin liquid and that the resulting composite holes with different 
excitations bound are distinct fractional particles with fundamentally 
different single-particle properties and different experimental 
signatures in the multi-particle ground state. In the gapless phase of 
the model, we consider a single hole and address the possibility of a 
coherent quasiparticle description by investigating its spectral 
function. We employ a variational treatment and also study a simplified 
one-dimensional problem to argue that a mobile hole has a finite 
quasiparticle weight which vanishes in the stationary limit.


Időpont: 2016. május 20. péntek, 10:15
Helyszín: BME Fizikai Intézet, Elméleti Fizika Tanszék,
Budafoki út 8. F-épület, III lépcsőház, szemináriumi szoba