1,721,014 research outputs found
Interaction-Induced Fractionalization and Topological Superconductivity in the Polar Molecules Anisotropic t-J Model
Full text linkWe show that the interplay between antiferromagnetic interaction and hole motion gives rise to a topological superconducting phase. This is captured by the one dimensional anisotropic t-J model which can be experimentally achieved with ultracold polar molecules trapped onto an optical lattice. As a function of the anisotropy strength we find that different quantum phases appear, ranging from a gapless Luttinger liquid to spin gapped conducting and superconducting regimes. In the presence of appropriate z anisotropy, we also prove that a phase characterized by nontrivial topological order takes place. The latter is described uniquely by a finite nonlocal string parameter and presents robust edge spin fractionalization. These results allow us to explore quantum phases of matter where topological superconductivity is induced by the interaction.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe
Homogeneous and domain-wall topological Haldane conductors with dressed Rydberg atoms
Full text linkThe interplay between antiferromagnetic interaction and hole motion is capable of inducing conducting Haldane phases with topological features described by a finite nonlocal string order parameter. Here we show that these states of matter are captured by the one-dimensional
t
−
J
z
model, which can be experimentally realized with dressed Rydberg atoms trapped onto a one-dimensional optical lattice. In the sector with vanishing total magnetization, exact calculations associated with the bosonization technique allow us to predict that both metallic and superconducting topological Haldane states can be achieved. With the addition of an appropriate magnetic field, the system enters a domain-wall structure with finite total magnetization. In this regime, the conducting Haldane states are confined in domains separated by regions where a fully polarized Luttinger liquid occurs. A procedure to dynamically stabilize such topological phases starting from a confined Ising state is also described
Detecting the tunneling rates for strongly interacting fermions on optical lattices
No full textinfo:eu-repo/semantics/publishe
Quantum bright solitons in the Bose-Hubbard model with site-dependent repulsive interactions
No full textWe introduce a one-dimensional spatially inhomogeneous Bose-Hubbard model (BHM) with the strength of the onsite repulsive interactions growing, with the discrete coordinate z(j), as vertical bar z(j)vertical bar(alpha) with alpha > 0. Recently, the analysis of the mean-field (MF) counterpart of this system has demonstrated self-trapping of robust unstaggered discrete solitons, under the condition alpha > 1. By using the numerically implemented method of the density matrix renormalization group, we demonstrate that, in a certain range of the interaction, the BHM also features self-trapping of the ground state into a soliton-like configuration, at alpha > 1, and remains weakly localized at alpha < 1. An essential quantum feature found in the BHM is a residual quasi-constant density of the background surrounding the soliton-like peak in the ground state, while in theMF limit the finite-density background is absent. Very strong onsite repulsion eventually destroys soliton-like states, driving the system, at integer densities, into the Mott phase with a spatially uniform density
Phase diagram of imbalanced strongly interacting fermions on a one-dimensional optical lattice
No full textinfo:eu-repo/semantics/publishe
Quantum bright solitons in a quasi-one-dimensional optical lattice
Full text linkWe study a quasi-one-dimensional attractive Bose gas confined in an optical lattice with a superimposed harmonic potential by analyzing the one-dimensional Bose-Hubbard Hamiltonian of the system. Starting from the three-dimensional many-body quantum Hamiltonian, we derive strong inequalities involving the transverse degrees of freedom under which the one-dimensional Bose-Hubbard Hamiltonian can be safely used. To have a reliable description of the one-dimensional ground state, which we call a quantum bright soliton, we use the density-matrix-renormalization-group (DMRG) technique. By comparing DMRG results with mean-field (MF) ones, we find that beyond-mean-field effects become relevant by increasing the attraction between bosons or by decreasing the frequency of the harmonic confinement. In particular, we find that, contrary to the MF predictions based on the discrete nonlinear Schrödinger equation, average density profiles of quantum bright solitons are not shape-invariant. We also use the time-evolving-block-decimation method to investigate the dynamical properties of bright solitons when the frequency of the harmonic potential is suddenly increased. This quantum quench induces a breathing mode whose period crucially depends on the final strength of the superimposed harmonic confinement
Non-local order parameters as a probe for phase transitions in the extended Fermi-Hubbard model
No full textThe Extended Fermi-Hubbard model is a rather studied Hamiltonian due to both its many applications and a rich phase diagram. Here we prove that all the phase transitions encoded in its one dimensional version are detectable via non-local operators related to charge and spin fluctuations. The main advantage in using them is that, in contrast to usual local operators, their asymptotic average value is finite only in the appropriate gapped phases. This makes them powerful and accurate probes to detect quantum phases. Our results indeed confirm that they are able to properly capture both the nature and the location of the transitions. Relevantly, this happens also for conducting phases with a spin gap, thus providing an order parameter for the identification of superconducting and paired superfluid phases
Hidden magnetism in periodically modulated one dimensional dipolar fermions
Full text linkThe experimental realization of time-dependent ultracold lattice systems has paved the way towards the implementation of new Hubbard-like Hamiltonians. We show that in a one-dimensional two-components lattice dipolar Fermi gas the competition between long range repulsion and correlated hopping induced by periodically modulated on-site interaction allows for the formation of hidden magnetic phases, with degenerate protected edge modes. The magnetism, characterized solely by string-like nonlocal order parameters, manifests in the charge and/or in the spin degrees of freedom. Such behavior is enlighten by employing Luttinger liquid theory and numerical methods. The range of parameters for which hidden magnetism is present can be reached by means of the currently available experimental setups and probes
Long-time rigidity to flux-induced symmetry breaking in quantum quench dynamics
Full text linkWe investigate how the breaking of charge conjugation symmetry C impacts on the dynamics of a half-filled fermionic lattice system after global quenches. We show that, when the initial state is insulating and the C symmetry is broken nonlocally by a constant magnetic flux, local observables, and correlations behave as if the symmetry were unbroken for a time interval proportional to the system size L. In particular, the local particle density of a quenched dimerized insulator remains pinned to 1/2 in each lattice site for an extensively long time, while it starts to significantly fluctuate only afterwards. Due to its qualitative resemblance to the sudden arrival of rapidly rising ocean waves, we dub this phenomenon the “tsunami effect.” Notably, it occurs even though the chiral symmetry is dynamically broken right after the quench. Furthermore, we identify a way to quantify the amount of symmetry breaking in the quantum state, showing that in insulators perturbed by a flux, it is exponentially suppressed as a function of the system size, while it is only algebraically suppressed in metals and in insulators with locally broken C symmetry. The robustness of the tsunami effect to weak disorder and interactions is demonstrated, and possible experimental realizations are propose
Frustrated magnets without geometrical frustration in bosonic flux ladders
Full text linkWe propose a scheme to realize a frustrated Bose-Hubbard model with ultracold
atoms in an optical lattice that comprises the frustrated spin-1/2 quantum XX
model. Our approach is based on a square ladder of magnetic flux close to
with one real and one synthetic spin dimension. Although this system does not
have geometrical frustration, we show that at low energies it maps into an
effective triangular ladder with staggered fluxes for specific values of the
synthetic tunneling. We numerically investigate its rich phase diagram and show
that it contains bond-ordered-wave and chiral superfluid phases. Our scheme
gives access to minimal instances of frustrated magnets without the need for
real geometrical frustration, in a setup of minimal experimental complexity.Comment: Main text: 5 pages + references, 3 figures; supplemental material: 10
pages + references, 2 figure
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