Robust nonequilibrium edge currents with and without band topology
arXiv:2106.05988 · doi:10.1103/PhysRevLett.128.120403
Abstract
We study two-dimensional bosonic and fermionic lattice systems under nonequilibrium conditions corresponding to a sharp gradient of temperature imposed by two thermal baths. In particular, we consider a lattice model with broken time-reversal symmetry that exhibits both topologically trivial and nontrivial phases. Using a nonperturbative Green function approach, we characterize the nonequilibrium current distribution in different parameter regimes. For both bosonic and fermionic systems, we find chiral edge currents that are robust against coupling to reservoirs and to the presence of defects on the boundary or in the bulk. This robustness not only originates from topological effects at zero temperature but, remarkably, also persists as a result of dissipative symmetries in regimes where band topology plays no role. Chirality of the edge currents implies that energy locally flows against the temperature gradient without any external work input. In the fermionic case, there is also a regime with topologically protected boundary currents, which nonetheless do not circulate around all system edges.
v1: 5+4 pages, 4+2 figures. Comments welcome. v2: Final author version
References in corpus (8)
- Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
- Quantum Spin Hall Insulator State in HgTe Quantum Wells
- Measuring the Chern number of Hofstadter bands with ultracold bosonic atoms
- Performance of a quantum heat engine at strong reservoir coupling
- Dissipative preparation of Chern insulators
- Emerging dissipative phases in a superradiant quantum gas with tunable decay
- Topology by Dissipation: Majorana Bosons in Metastable Quadratic Markovian Dynamics
- Thermal Instability of Protected End States in a 1-D Topological Insulator