scholarly journals Ground state degeneracy of the Pauli–Fierz Hamiltonian with spin

2001 ◽  
Vol 5 (6) ◽  
pp. 1091-1104 ◽  
Author(s):  
F. Hiroshima ◽  
H. Spohn
Keyword(s):  
Ground State ◽  
Ground State Degeneracy

Anyon representation of the ground-state degeneracy of the quantum frustratedXYmodel

1992 ◽  
Vol 45 (10) ◽  
pp. 5737-5739 ◽  
Author(s):  
Maria Cristina Diamantini ◽  
Pasquale Sodano
Keyword(s):  
Ground State ◽  
Ground State Degeneracy

scholarly journals Boundary states for chiral symmetries in two dimensions

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Philip Boyle Smith ◽  
David Tong
Keyword(s):  
Boundary Conditions ◽  
Ground State ◽  
Zero Mode ◽  
Central Charge ◽  
Two Dimensions ◽  
Dirac Fermions ◽  
Chiral Symmetries ◽  
Boundary States ◽  
Ground State Degeneracy ◽  
Left And Right

Abstract We study boundary states for Dirac fermions in d = 1 + 1 dimensions that preserve Abelian chiral symmetries, meaning that the left- and right-moving fermions carry different charges. We derive simple expressions, in terms of the fermion charge assignments, for the boundary central charge and for the ground state degeneracy of the system when two different boundary conditions are imposed at either end of an interval. We show that all such boundary states fall into one of two classes, related to SPT phases supported by (−1)F , which are characterised by the existence of an unpaired Majorana zero mode.

scholarly journals Screw dislocations in the X-cube fracton model

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Nandagopal Manoj ◽  
Kevin Slagle ◽  
Wilbur Shirley ◽  
Xie Chen
Keyword(s):  
Screw Dislocation ◽  
Layered Structure ◽  
Ground State ◽  
The Other ◽  
Screw Dislocations ◽  
Topological States ◽  
Ground State Degeneracy ◽  
Induced Motion ◽  
D Model

The X-cube model, a prototypical gapped fracton model, was shown in Ref. [1] to have a foliation structure. That is, inside the 3+1 D model, there are hidden layers of 2+1 D gapped topological states. A screw dislocation in a 3+1 D lattice can often reveal nontrivial features associated with a layered structure. In this paper, we study the X-cube model on lattices with screw dislocations. In particular, we find that a screw dislocation results in a finite change in the logarithm of the ground state degeneracy of the model. Part of the change can be traced back to the effect of screw dislocations in a simple stack of 2+1 D topological states, hence corroborating the foliation structure in the model. The other part of the change comes from the induced motion of fractons or sub-dimensional excitations along the dislocation, a feature absent in the stack of 2+1D layers.

scholarly journals Continuous ground-state degeneracy of classical dipoles on regular lattices

2019 ◽  
Vol 100 (1) ◽  
Author(s):  
Dominik Schildknecht ◽  
Michael Schütt ◽  
Laura J. Heyderman ◽  
Peter M. Derlet
Keyword(s):  
Ground State ◽  
Ground State Degeneracy ◽  
Regular Lattices
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