Heat, particle, and chiral currents in a boundary driven bosonic ladder in the presence of a gauge field

Abstract

We consider a bosonic two-legged ladder whose two-band energy spectrum can be tuned in the presence of a uniform gauge field, to four distinct scenarios: degenerate or non-degenerate ground states with gapped or gapless energy bands. We couple the ladder to two baths at different temperatures and chemical potentials and analyze the efficiency and power generated in the linear as well as nonlinear response regime. Our results, obtained with the Green's function method, show that the maximum performance efficiency and generated power are strongly dependent on the type of the underlying energy spectrum. We also show that the ideal scenario for efficient energy conversion, as well as power generation, corresponds to the case in which the spectrum has a gap between the bands, and the bands are narrower.

Non-equilibrium boundary driven quantum systems: models, methods and properties

“…This system has been studied both theoretically (also for interacting bosons) and experimentally for a number of years with different analytical and numerical techniques, and different experimental setups (Atala et al, 2014;Denniston and Tang, 1995;Donohue and Giamarchi, 2001;Granato, 1990;Kardar, 1986;Nishiyama, 2000;Orignac and Giamarchi, 2001;van Oudenaarden and Mooij, 1996). However, only recently the effects of the phase transition on the boundary driven transport properties have been explored Poletti, 2016, 2017a;Rivas and Martin-Delgado, 2017;Xing et al, 2020).…”

“…( 35) in Sec.II.C.2], and showed the robustness of the chiral, heat and particle currents versus the presence of disorder, thus showing the importance of the underlying Meissner phase. In (Xing et al, 2020) the authors used a non-equilibrium Green's functions approach, which unlike global GKSL is an exact method, to study chiral, heat and particle current for a broad range of system parameters. They showed how these three currents are significantly different depending on whether the underlying ground state is in the Meissner or vortex phase, and on the presence or absence of a gap between the two bands of the energy spectrum of the system.…”

“…( 19) to induce a current, one observes that the bosonic ladder shows a sharp change in the conductance at this transition. For thermal baths, see (Rivas and Martin-Delgado, 2017;Xing et al, 2020), there are no sharp changes in the conductance, but one can still observe changes in the magnitude and patterns in the current due to the presence of ground state and excited states QPTs, and even changes in its thermoelectric-like properties (Xing et al, 2021).…”

Robust nonequilibrium edge currents with and without band topology

“…This effect was recently reported in Refs. [14,45] for bosonic lattices governed by the Hofstadter Hamiltonian. Now, we can see that the key requisite for this behavior is not the nontrivial band topology of the lattice, but rather the nonzero Berry curvature in a regime of sufficiently weak system-bath coupling [Fig.…”

Robust nonequilibrium surface currents in the 3D Hofstadter model

“…This exotic edge current, which has also been observed in other 2D models [28] (see Refs. [29][30][31] for quasi-one-dimensional studies), is robustly protected by symmetry properties with respect to the presence of point-like defects, and remains stable for a wide range of reservoir coupling strengths [28]. Such crosscurrents were first thought to be an intrinsically onedimensional phenomenon.…”