Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice

Abstract

We investigate the transport properties of neutral, fermionic atoms passing through a onedimensional quantum wire containing a mesoscopic lattice. The lattice is realized by projecting individually controlled, thin optical barriers on top of a ballistic conductor. Building an increasingly longer lattice, one site after another, we observe and characterize the emergence of a band insulating phase, demonstrating control over quantum-coherent transport. We explore the influence of atom-atom interactions and show that the insulating state persists as contact interactions are tuned from moderately to strongly attractive. Using bosonization and classical Monte-Carlo simulations we analyze such a model of interacting fermions and find good qualitative agreement with the data. The robustness of the insulating state supports the existence of a Luther-Emery liquid in the one-dimensional wire. Our work realizes a tunable, site-controlled lattice Fermi gas strongly coupled to reservoirs, which is an ideal test bed for non-equilibrium many-body physics. PACS numbers:arXiv:1708.01250v3 [cond-mat.quant-gas]

Open Bose-Hubbard chain: Pseudoclassical approach

“…Transport phenomena with neutral atoms is an active area of research in the experimental cold-atom physics. This includes Josephson oscillations of Bose atoms in a double-well potential [1,2], atomic Bloch oscillations in quasi one-dimensional optical lattices [3,4], refill dynamics in the presence of the induced losses [5,6], quantized current in the engineered transport channel [7][8][9] -to mention a few of phenomena under scrutiny. From the theoretical viewpoint these experiments refer to (or even are aimed to realize) some paradigm models of the many-body physics that, on the one hand, are complex enough to capture the physics of the discussed phenomenon but, on the other hand, are simple enough to admit an analytical treatment.…”

Quantized Conductance through a Spin-Selective Atomic Point Contact

“…Our work demonstrates how transport measurements are sensitive to minute interaction effects occurring on the scale of the Fermi wavelength from the integration of a weak transport signal. Our capability to spinengineer potentials can be readily extended to more complex structures [24] and opens avenues for exploring the transport dynamics of strongly-correlated systems, where novel nonequilibrium spin and heat transport [28,29] and exotic phases of matter [5] could be observed.…”

Drude weight increase by orbital and repulsive interactions in fermionic ladders

“…Interesting perspectives concern the geometrical interpretation of the effects discussed in this work [60] and the study of the interplay of quantum impurities and bulk interactions in such systems [31,61]. Moreover, it is completely open for investigation how the interactions studied in this paper affect a setup in which energy and mass transport are induced by biased reservoirs [62][63][64][65][66][67]. In this case, interactions are not expected to affect the mass conductance [68], but only the thermal conductance, leading to the violation of the Wiedemann-Franz law [66].…”