Erwin Schrödinger Center for Quantum Science & Technology (ESQ)

The competition and interplay between superfluid and magnetic behaviours is a fundamental question in many-body physics, magnetization (spin polarization) and superfluidity (pairing) being two types of order parameter mutually incompatible. A special situation in fermionic systems with spin imbalance is the exotic Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) superfluid state in which the pairs have finite momenta, and the regions of paired fermions with alternating signs of the order parameter are separated by spin-polarized domain walls consisting of majority spins. In this Discovery project we propose to realize experiments with a single layer of 1D array of Fermi gases, where we can directly observe single tubes. We aim to confirm the FFLO state by establishing spatially resolved, local measurements of the superfluid order parameter for 1D Fermi gases. Our experimental approaches include correlation measurements to characterize the superfluid state, to perform molecule projection to realize boson interference and reveal the phase modulation of the order parameter, and to observe phase sensitive tunnelling or a Josephson junction.