Intrinsically Gapless Topological Phases
- URL: http://arxiv.org/abs/2008.06638v1
- Date: Sat, 15 Aug 2020 03:37:05 GMT
- Title: Intrinsically Gapless Topological Phases
- Authors: Ryan Thorngren, Ashvin Vishwanath, Ruben Verresen
- Abstract summary: Topology in quantum matter is typically associated with gapped phases.
Intrinsically gapless SPT phases have no gapped counterpart.
On-site symmetries act in an anomalous fashion at low energies.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Topology in quantum matter is typically associated with gapped phases. For
example, in symmetry protected topological (SPT) phases, the bulk energy gap
localizes edge modes near the boundary. In this work we identify a new
mechanism that leads to topological phases which are not only gapless but where
the absence of a gap is essential. These `intrinsically gapless SPT phases'
have no gapped counterpart and are hence also distinct from recently discovered
examples of gapless SPT phases. The essential ingredient of these phases is
that on-site symmetries act in an anomalous fashion at low energies.
Intrinsically gapless SPT phases are found to display several unique properties
including (i) protected edge modes that are impossible to realize in a gapped
system with the same symmetries, (ii) string order parameters that are likewise
forbidden in gapped phases, and (iii) constraints on the phase diagram obtained
upon perturbing the phase. We verify predictions of the general theory in a
specific realization protected by $\mathbb Z_4$ symmetry, the one dimensional
Ising-Hubbard chain, using both numerical simulations and effective field
theory. We also discuss extensions to higher dimensions and possible
experimental realizations.
Related papers
- Geometric Phase of a Transmon in a Dissipative Quantum Circuit [44.99833362998488]
We study the geometric phases acquired by a paradigmatic setup: a transmon coupled to a superconductor resonating cavity.
In the dissipative model, the non-unitary effects arise from dephasing, relaxation, and decay of the transmon coupled to its environment.
Our approach enables a comparison of the geometric phases obtained in these models, leading to a thorough understanding of the corrections introduced by the presence of the environment.
arXiv Detail & Related papers (2024-01-22T16:41:00Z) - Gapless symmetry-protected topological phases and generalized deconfined critical points from gauging a finite subgroup [0.6675805308519986]
Gauging a finite subgroup of a global symmetry can map conventional phases and phase transitions to unconventional ones.
In this work, we study an emergent $mathbbZ$-gauged system with global $U(1)$.
We also discuss the stability of these phases and the critical points to small perturbations and their potential experimental realizations.
arXiv Detail & Related papers (2024-01-22T05:46:49Z) - 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) - Boundary deconfined quantum criticality at transitions between symmetry-protected topological chains [0.0]
This work highlights the rich unexplored physics of criticality between nontrivial topological phases.
It provides insights into the burgeoning field of gapless topological phases.
arXiv Detail & Related papers (2022-08-25T17:59:26Z) - Noise-resilient Edge Modes on a Chain of Superconducting Qubits [103.93329374521808]
Inherent symmetry of a quantum system may protect its otherwise fragile states.
We implement the one-dimensional kicked Ising model which exhibits non-local Majorana edge modes (MEMs) with $mathbbZ$ parity symmetry.
MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism.
arXiv Detail & Related papers (2022-04-24T22:34:15Z) - Hidden Single-Qubit Topological Phase Transition without Gap Closing in
Anisotropic Light-Matter Interactions [0.0]
Conventionally the occurrence of topological phase transitions (TPTs) requires gap closing, whereas there are also unconventional cases without need of gap closing.
A sign for the unconventional TPT is unveiled via the transition from amplitude squeezing to phase squeezing in the gapped phase.
arXiv Detail & Related papers (2021-12-25T17:54:34Z) - Unsupervised Learning of Symmetry Protected Topological Phase
Transitions [0.0]
In particular, we show that the phase transitions associated with these phases can be detected in different bosonic and fermionic models in one dimension.
Our approach serves as an inexpensive computational method for detecting topological phases transitions associated with SPT systems.
arXiv Detail & Related papers (2021-11-16T19:34:16Z) - Experimentally Detecting Quantized Zak Phases without Chiral Symmetry in
Photonic Lattices [14.450949607717437]
We experimentally realize an extended Su-Schrieffer-Heeger model with broken chiral symmetry.
Our results demonstrate that inversion symmetry protects the quantized Zak phase, but edge states can disappear in the topological nontrivial phase.
Our photonic lattice provides a useful platform to study the interplay among topological phases, symmetries, and the bulk-boundary correspondence.
arXiv Detail & Related papers (2021-09-28T13:35:44Z) - Quotient symmetry protected topological phenomena [0.0]
We show that topological phenomena can be stable over a large part of parameter space even when the bulk is strictly speaking in a trivial phase of matter.
Although the Haldane phase is then adiabatically connected to a product state, we show that characteristic phenomena -- edge modes, entanglement degeneracies and bulk phase transitions -- remain parametrically stable.
arXiv Detail & Related papers (2021-02-17T19:00:04Z) - Quantum anomalous Hall phase in synthetic bilayers via twistless
twistronics [58.720142291102135]
We propose quantum simulators of "twistronic-like" physics based on ultracold atoms and syntheticdimensions.
We show that our system exhibits topologicalband structures under appropriate conditions.
arXiv Detail & Related papers (2020-08-06T19:58:05Z) - Dynamical solitons and boson fractionalization in cold-atom topological
insulators [110.83289076967895]
We study the $mathbbZ$ Bose-Hubbard model at incommensurate densities.
We show how defects in the $mathbbZ$ field can appear in the ground state, connecting different sectors.
Using a pumping argument, we show that it survives also for finite interactions.
arXiv Detail & Related papers (2020-03-24T17:31:34Z)
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.