28 Nov
2017
28 Nov
'17
1:14 p.m.
ITAMP Lunch Seminar
Speaker: Adrian Feiguin, (Northeastern University)
Date: Thursday, November 30th
Time: 12:00-1:00 pm
Includes Pizza.
Title: Spin incoherent behavior in strongly correlated low dimensional systems
Abstract: When electrons (or other quantum particles with an internal ``spin" degree
of freedom) are confined in one spatial dimension, they loose their identity as individual
particles. The excitations become collective modes carrying spin, and charge, with each
degree of freedom being characterized by a different energy scale. While the basic
theoretical understanding of spin-charge separation in one-dimension, known as ``Luttinger
liquid theory'', has existed for some time, recently a previously unidentified
regime of strongly interacting one-dimensional systems at finite temperature came to
light: The ``spin-incoherent Luttinger liquid". This occurs when the temperature is
larger than the characteristic spin energy scale. The key to establishing both Luttinger
liquid behavior and spin-incoherent Luttinger liquid behavior in experiment is detailed
knowledge of the spectral properties.
I will present a numerical study of the finite-temperature spectral properties of a
one-dimensional fermionic gas in the spin-incoherent regime using the time-dependent
density matrix renormalization group method. This approach enables us to quantitatively
handle the experimentally relevant and theoretically challenging ``crossover" regime
between the Luttinger liquid and spin-incoherent Luttinger liquid limits. Finally, I will
show that spin-incoherent behavior can be realized in the *ground-state* of model
Hamiltonians, such as Hubbard ladders, and the Kondo lattice.
Location: B-106 @ Center for Astrophysics (60 Garden Street)
Directions: After entering the lobby of the CfA, turn right to enter the hallway of the B
building. In the hallway, turn right again, B-106 will be at the end of the hallway on the
left side.