Topological and non-topological features of generalized Su-Schrieffer-Heeger models

• URL: http://arxiv.org/abs/2004.11050v1
• Date: Thu, 23 Apr 2020 10:08:00 GMT
• Title: Topological and non-topological features of generalized Su-Schrieffer-Heeger models
• Authors: N. Ahmadi, J. Abouie, and D. Baeriswyl
• Abstract summary: The Su-Schrieffer-Heeger Hamiltonian is studied at half filling for an even number of sites. We find a variety of topologically non-trivial phases, characterized by different numbers of edge states. We study specifically next-nearest-neighbor hopping with amplitudes $t_a$ and $t_b$ for the $A$ and $B$ sublattices, respectively.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The (one-dimensional) Su-Schrieffer-Heeger Hamiltonian, augmented by spin-orbit coupling and longer-range hopping, is studied at half filling for an even number of sites. The ground-state phase diagram depends sensitively on the symmetry of the model. Charge-conjugation (particle-hole) symmetry is conserved if hopping is only allowed between the two sublattices of even and odd sites. In this case (of BDI symmetry) we find a variety of topologically non-trivial phases, characterized by different numbers of edge states (or, equivalently, different quantized Zak phases). The transitions between these phases are clearly signalled by the entanglement entropy. Charge-conjugation symmetry is broken if hopping within the sublattices is admitted (driving the system into the AI symmetry class). We study specifically next-nearest-neighbor hopping with amplitudes $t_a$ and $t_b$ for the $A$ and $B$ sublattices, respectively. For $t_a=t_b$ parity is conserved, and also the quantized Zak phases remain unchanged in the gapped regions of the phase diagram. However, metallic patches appear due to the overlap between conduction and valence bands in some regions of parameter space. The case of alternating next-nearest neighbor hopping, $t_a=-t_b$, is also remarkable, as it breaks both charge-conjugation $C$ and parity $P$ but conserves the product $CP$. Both the Zak phase and the entanglement spectrum still provide relevant information, in particular about the broken parity. Thus the Zak phase for small values of $t_a$ measures the disparity between bond strengths on $A$ and $B$ sublattices, in close analogy to the proportionality between the Zak phase and the polarization in the case of the related Aubry-Andr\'e model.

Related papers

• Mobility edges in pseudo-unitary quasiperiodic quantum walks [0.0]
  Floquet quasicrystal simulates the motion of Bloch electrons in a homogeneous magnetic field in discrete time steps. We show that the model is still pseudo-unitary'' For the first time, we observe a second transition that appears to be unique to the discrete-time setting.
  arXiv  Detail & Related papers  (2024-11-25T19:00:01Z)
• Exactly solvable models for fermionic symmetry-enriched topological phases and fermionic 't Hooft anomaly [33.49184078479579]
  The interplay between symmetry and topological properties plays a very important role in modern physics. How to realize all these fermionic SET (fSET) phases in lattice models remains to be a difficult open problem.
  arXiv  Detail & Related papers  (2024-10-24T19:52:27Z)
• Topological phase transition in fluctuating imaginary gauge fields [0.0]
  We investigate the exact solvability and point-gap topological phase transitions in non-Hermitian lattice models. By employing suitable imaginary gauge transformations, it is revealed that a lattice characterized by any given $g_n$ is spectrally equivalent to a lattice devoid of fields.
  arXiv  Detail & Related papers  (2024-06-11T07:10:03Z)
• Dissipative phase transition: from qubits to qudits [0.0]
  We investigate the fate of dissipative phase transitions in quantum many-body systems when the individual constituents are qudits instead of qubits. Considering qudits instead of qubits opens new perspectives on accessing rich phase diagrams in open many-body systems.
  arXiv  Detail & Related papers  (2024-05-02T12:08:28Z)
• Emergence of non-Abelian SU(2) invariance in Abelian frustrated fermionic ladders [37.69303106863453]
  We consider a system of interacting spinless fermions on a two-leg triangular ladder with $pi/2$ magnetic flux per triangular plaquette. Microscopically, the system exhibits a U(1) symmetry corresponding to the conservation of total fermionic charge, and a discrete $mathbbZ$ symmetry. At the intersection of the three phases, the system features a critical point with an emergent SU(2) symmetry.
  arXiv  Detail & Related papers  (2023-05-11T15:57:27Z)
• A hybrid quantum algorithm to detect conical intersections [39.58317527488534]
  We show that for real molecular Hamiltonians, the Berry phase can be obtained by tracing a local optimum of a variational ansatz along the chosen path. We demonstrate numerically the application of our algorithm on small toy models of the formaldimine molecule.
  arXiv  Detail & Related papers  (2023-04-12T18:00:01Z)
• Theory of free fermions under random projective measurements [43.04146484262759]
  We develop an analytical approach to the study of one-dimensional free fermions subject to random projective measurements of local site occupation numbers. We derive a non-linear sigma model (NLSM) as an effective field theory of the problem.
  arXiv  Detail & Related papers  (2023-04-06T15:19:33Z)
• Exact solution of a non-Hermitian $\mathscr{PT}$-symmetric Heisenberg spin chain [0.0]
  We construct the exact solution of a non-Hermitian $mathscrPT$-symmetric isotropic Heisenberg spin chain with integrable boundary fields. We find that both $A$ and $B$ type phases can be further divided into sub-phases which exhibit different ground states.
  arXiv  Detail & Related papers  (2023-01-15T02:32:44Z)
• Superdiffusion in random two dimensional system with time-reversal symmetry and long-range hopping [45.873301228345696]
  localization problem in the crossover regime for the dimension $d=2$ and hopping $V(r) propto r-2$ is not resolved yet. We show that for the hopping determined by two-dimensional anisotropic dipole-dipole interactions there exist two distinguishable phases at weak and strong disorder.
  arXiv  Detail & Related papers  (2022-05-29T16:53:20Z)
• Discrete Scale-Invariant Boson-Fermion Duality in One Dimension [0.0]
  We introduce models of one-dimensional $n(geq3)$-body problems that undergo phase transition from a continuous scale-invariant phase to a discrete scale-invariant phase. Thanks to the boson-fermion duality, these results can be applied equally well to both bosons and fermions.
  arXiv  Detail & Related papers  (2021-10-19T04:00:00Z)
• Anisotropy-mediated reentrant localization [62.997667081978825]
  We consider a 2d dipolar system, $d=2$, with the generalized dipole-dipole interaction $sim r-a$, and the power $a$ controlled experimentally in trapped-ion or Rydberg-atom systems. We show that the spatially homogeneous tilt $beta$ of the dipoles giving rise to the anisotropic dipole exchange leads to the non-trivial reentrant localization beyond the locator expansion.
  arXiv  Detail & Related papers  (2020-01-31T19:00:01Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.