The exchange coupling between quantum mechanical spins lies at the origin of magnetism. We report on observation nearest-neighbor magnetic spin correlations emerging in many-body state a thermalized Fermi gas an optical lattice. key to obtaining short-range order is local redistribution entropy within lattice structure. This achieved tunable-geometry lattice, which also enables detection correlations. load low-temperature two-component with repulsive interactions into either dimerized or...

We employ a quantum Liouville equation with relaxation to model the recently observed anomalous Hall effect in graphene irradiated by an ultrafast pulse of circularly polarized light. In weak-field regime, we demonstrate that originates from asymmetric population photocarriers Dirac bands. By contrast, strong-field system is driven into non-equilibrium steady state well-described topologically non-trivial Floquet-Bloch Here, current combination imbalance these dressed bands together smaller...

Far and mid infrared optical pulses have been shown to induce non-equilibrium unconventional orders in complex materials, including photo-induced ferroelectricity quantum paraelectrics, magnetic polarization antiferromagnets transient superconducting correlations the normal state of cuprates organic conductors. In case superconductivity, femtosecond drives generally resulted electronic properties that disappear immediately after excitation, evidencing a lacks intrinsic rigidity. Here, we...

We create an artificial graphene system with tunable interactions and study the crossover from metallic to Mott insulating regimes, both in isolated coupled two-dimensional honeycomb layers. The consists of a two-component spin mixture ultracold atomic Fermi gas loaded into hexagonal optical lattice. For strong repulsive interactions, we observe suppression double occupancy measure gapped excitation spectrum. present quantitative comparison between our measurements theory, making use novel...

We demonstrate a versatile method for creating state-dependent optical lattices by applying magnetic field gradient modulated in time. This allows tuning the relative amplitude and sign of tunneling different internal states. observe substantially momentum distributions depending on spin state fermionic ^{40}K atoms. Using dipole oscillations, we probe spin-dependent band structure find good agreement with theory. In situ expansion dynamics that one can be completely localized while others...

We investigate the topological properties of Floquet-engineered twisted bilayer graphene above magic angle driven by circularly polarized laser pulses. Employing a full Moir\'e-unit-cell tight-binding Hamiltonian based on first-principles electronic structure we show that band topology in bilayer, at twisting angles 1.05$^\circ$, essentially corresponds to one single-layer graphene. However, ability open topologically trivial gaps this system bias voltage between layers enables phase diagram...

Abstract Photo-excitation at terahertz and mid-infrared frequencies has emerged as an effective way to manipulate functionalities in quantum materials, some cases creating non-equilibrium phases that have no equilibrium analogue. In K 3 C 60 , a metastable zero-resistance phase was observed optical properties, nonlinear electrical transport pressure dependencies compatible with high-temperature superconductivity. Here we demonstrate two-orders-of-magnitude increase photo-susceptibility near...

Abstract Coherent optical driving in quantum solids is emerging as a research frontier, with many reports of interesting non-equilibrium phases 1–4 and transient photo-induced functional phenomena such ferroelectricity 5,6 , magnetism 7–10 superconductivity 11–14 . In high-temperature cuprate superconductors, coherent certain phonon modes has resulted state superconducting-like properties, observed far above their transition temperature T c throughout the pseudogap phase 15–18 However,...

We report on the observation of anti-ferromagnetic correlations ultracold fermions in a variety optical lattice geometries that are well described by Hubbard model, including dimers, 1D chains, ladders, isolated and coupled honeycomb planes, as square cubic lattices. The dependence strength spin specific geometry is experimentally studied measuring along different tunneling links, where redistribution between links observed. By crossover distinct geometries, we demonstrate an effective...

We realize and study the ionic Hubbard model using an interacting two-component gas of fermionic atoms loaded into optical lattice. The bipartite lattice has a honeycomb geometry with staggered energy offset that explicitly breaks inversion symmetry. Distinct density-ordered phases are identified noise correlation measurements atomic momentum distribution. For weak interactions induces charge density wave. strong repulsive we detect suppression doubly occupied sites, as expected for Mott...

We demonstrate how the properties of light-induced electronic Floquet states in solids impact natural physical observables, such as transport properties, by capturing environmental influence on electrons. include environment dissipative processes, inter-band decay and dephasing, often ignored predictions. These processes determine band occupations emergent steady state, balancing out optical driving force. In order to benchmark illustrate our framework for physics a realistic solid, we...

Near-resonant periodic driving of quantum systems promises the implementation a large variety novel states, though their preparation and measurement remains challenging. We address these aspects in model system consisting interacting fermions periodically driven array double wells created by an optical lattice. The singlet triplet fractions occupancy Floquet states are measured behavior as function interaction strength is analyzed high- low-frequency regimes. demonstrate full control state...

Using two-frequency driving in two dimensions opens up new possibilities for Floquet engineering, which range from controlling specific symmetries to tuning the properties of resonant gaps. In this work, we study two-band lattice models subject two-tone and analyze resulting effective band structures both numerically analytically. On one hand, extend methodology Sandholzer et al. [Phys. Rev. Res. 4, 013056 (2022)] find competing topological phases a simple Bravais when drives at...

We study the anisotropic 3D Hubbard model with increased nearest-neighbor tunneling amplitudes along one direction using dynamical cluster approximation and compare results to a quantum simulation experiment of ultracold fermions in an optical lattice. find that short-range spin correlations are significantly enhanced stronger amplitudes. Our agree experimental observations show temperature is lower than strong amplitude. characterize system by examining beyond neighboring sites determine...

We propose and analyze a general scheme to create chiral topological edge modes within the bulk of two-dimensional engineered quantum systems. Our method is based on implementation interfaces, designed system, where topologically-protected localize freely propagate in unidirectional manner. This illustrated through an optical-lattice realization Haldane model for cold atoms, additional spatially-varying lattice potential induces distinct phases separated regions space. present two realistic...

Resonant optical excitation of certain molecular vibrations in κ-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Br has been shown to induce transient superconductinglike properties at temperatures far above equilibrium T_{c}. Here, we report experiments across the bandwidth-tuned phase diagram this class materials, and study Mott insulator κ-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Cl metallic compound κ-(BEDT-TTF)_{2}Cu(NCS)_{2}. We find nonequilibrium photoinduced superconductivity only κ-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Br,...

We propose a novel nonequilibrium phenomenon, through which prompt quench from metal to transient superconducting state can induce large oscillations of the order parameter amplitude. argue that this oscillating mode acts as source parametric amplification incident radiation. report experimental results on optically driven K3C60 are consistent with these predictions. The effect is found disappear when onset excitation becomes slower than Higgs-mode period, theory proposed here. These open...

We study low-frequency linearly polarized laser-dressing in materials with valley (graphene and hexagonal-Boron-Nitride) topological (Dirac- Weyl-semimetals) properties. In Dirac-like dispersing bands, the laser substantially moves Dirac nodes away from their original position, movement direction can be fully controlled by rotating polarization. prove that this effect originates band nonlinearities nodes. further demonstrate physical mechanism is widely applicable move positions of minima...