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Ultrafast photoexcitation stabilizes new states of matter with rich out-of-equilibrium behaviours. Here, Lantzet al. report a transient non-thermal phase developing immediately after photoexcitation in V₂O₃, shedding a light on optical manipulation of strongly correlated systems.

A several-fold reduction in temperature is accomplished using a neutral-atom Hubbard quantum simulator by transforming a low-entropy product state into strongly correlated states of interest via dynamic control of the model parameters.

Strongly interacting interlayer excitons and the interplay between excitons and electronic states have recently been studied in moire superlattices. Here the authors study moire WS₂/WSe₂ heterobilayer with tuneable electron and exciton populations and find signatures of an excitonic Mott insulating state.

The realization of dipolar quantum solids with an ultracold gas of magnetic atoms in an optical lattice ushers in quantum simulation of many-body systems with long-range anisotropic interactions.

The magnetic phases of the geometrically frustrated triangular lattice Hubbard model are directly investigated using ultracold fermionic atoms, indicating a possible transition to ferromagnetism at a filling of 1.2.

The goal of quantum simulation is to probe many-body phenomena in controlled systems, but Fermi-Hubbard phenomena are typically hard to simulate in cold atomic. Here, the authors simulate them with subsurface dopants in silicon, achieving a low effective temperature and reading out spin states with STM.

Emergence of Nagaoka polarons and kinetic magnetism is observed in a Hubbard system realized with strongly interacting fermions trapped in a triangular optical lattice.

Spin liquids are states of matter that reside outside the regime where the Landau paradigm for classifying phases can be applied. This makes them interesting, but also hard to find, as no conventional order parameters exist. The authors demonstrate that topologically ordered spin-liquid phases can be identified by numerically evaluating a measure known as topological entanglement entropy.

A new platform comprising large-scale 2D arrays of quantum dots patterned with sub-nanometre precision, with each quantum dot defined by tens of phosphorus atoms doped into silicon, allows for analogue simulation of quantum materials on arbitrary lattices.

Ultracold atomic gases in optical lattices potentially offer simulations of condensed-matter phenomena beyond what theory and computations can access; compensated optical lattice techniques applied to the Hubbard model now enable unprecedented low temperatures to be reached for fermions — only 1.4 times that of the antiferromagnetic phase transition, approaching the limits of present modelling techniques.

Recent experiments have identified the underlying model of one-dimensional cuprate chains as the extended Hubbard model with attractive near-neighbor interactions. Here, the authors use many-body calculations to create an exact ground-state phase diagram of this model, demonstrating a rich diversity of exotic quantum states, and providing valuable guidance for realizing unconventional superconductivity in the system.

The electronic behaviour of complex oxides such as LaNiO₃ depends on many intrinsic and extrinsic factors, making it challenging to identify microscopic mechanisms. Here the authors demonstrate the influence of oxygen vacancies on the thickness-dependent metal-insulator transition of LaNiO₃ films.

Unconventional quasiparticles carrying spin but not electric charge emerge in quantum spin liquid phases. The Kondo interaction of these spinon quasiparticles with magnetic impurities may now have been observed.

Controlling electron spin states with light is vital for quantum technologies but requires electronic excitations with net spin. Now a molecular diradical with two trityl radical groups coupled via a meta-linked fluorene bridge has been developed that features luminescent singlet and triplet excitons. The spins in the ground state can be written and read using photons, giving rise to broad magnetic and microwave modulation of the photoluminescence.

Fluctuations arising from Heisenberg's uncertainty principle enable quantum systems to exhibit phase transitions even at zero temperature. For example, a superfluid-to-insulator transition has been observed for weakly interacting bosonic atomic gases. Here the authors report a novel type of quantum phase transition in a strongly interacting, one-dimensional quantum gas of bosonic caesium atoms. The results open up the experimental study of ultracold gases in a new regime.

Magnetic excitations in infinite-layer cuprates have been intensively studied. Here the authors use resonant inelastic x-ray scattering and theoretical calculations to study magnons in thin films of SrCuO₂, finding distinct magnon dispersion attributed to renormalization due to quantum fluctuations.

A new class of moiré materials based on monolayers with triangular lattices and low-energy states at the M points of the Brillouin zone is introduced, demonstrating emergent momentum-space non-symmorphic symmetries, a kagome plane-wave lattice structure, and potential quasi-one-dimensionality.

Abrupt changes, or kinks, in electron dispersion, caused by the coupling of electronic excitations to collective modes, could provide insights into the superconducting pairing mechanism. Here the authors report dispersion kinks driven by electronic correlations in the normal state of an iron-based superconductor.

Superconductivity induced on a topological insulator’s surface may realize Majorana modes. Here, Herbrych et al. predict that a large Coulomb interaction helps develop a spiral spin order, which is a topological state at the edge of a canonical superconductor with orbital degrees of freedom.

The authors study epitaxial thin films of the pyrochlore-sublattice compound LiTi2O4 by RIXS and ARPES. They observe cooperation between strong electron correlations and strong electron-phonon coupling, giving rise to a mobile polaronic ground state in which charge motion and lattice distortions are coupled.

Quantum Fisher information is a measure of entanglement that has been previously extracted from equilibrium spectra of quantum materials. Here the authors extend this approach to non-equilibrium systems probed by time-resolved resonant inelastic x-ray scattering measurements.

Some quantum spin liquids are expected to have an effective Fermi surface of fractionalized spinon excitations. The two-dimensional spin liquid candidate 1T-TaSe₂ has charge density modulations that may be caused by an unstable spinon Fermi surface.

A Mott insulator forms when strong interactions between particles cause them to become localized. A cold atom simulator has now been used to realize a selective Mott insulator in which atoms are localized or propagating depending on their spin state.

Using particle-by-particle assembly and adiabatic manipulation of disorder, low-entropy, strongly correlated quantum fluids of light are constructed, opening up new possibilities for the preparation of exotic phases of synthetic matter.

Quantum simulation offers an unparalleled computational resource, but realizing it for fermionic systems is challenging due to their particle statistics. Here the authors report on the time evolutions of fermionic interactions implemented with digital techniques on a nine-qubit superconducting circuit.

Transition metal dichalcogenide heterostructures with layers of localized and itinerant electrons are candidates for heavy fermion lattices. The authors report delocalization of Mott electrons in a monolayer of 1T-TaS₂ on a bulk metallic 2H-TaS₂ substrate, indicating the formation of a coherent Kondo lattice.

Metallic surface states on CoO₂ and Pd terminated surfaces due to electronic reconstruction have been observed in the CoO₂-based delafossites. In contrast, here the authors report an interesting insulating state on the CrO₂ terminated surface of PdCrO₂ due to charge-disproportionation.

A detailed resonant inelastic X-ray scattering (RIXS) study of a series of well-known cuprate superconductors reveals a correlation between the number of apical oxygens in these systems, and the strength of their in-plane exchange interaction.

The emergence of quasiparticles in a doped Mott insulator is the key to understanding high Tc cuprate superconductivity - a major quest in condensed matter physics. Here, the authors investigate the angle-resolved photoemission spectroscopy in the cuprates and observe how the quasiparticle emerges from the Mott insulating regime.

At the microscopic level, the localized spins arise due to the electron-electron interactions. Here, the authors show how a topological phase of the Haldane spin chain emerges in a two-orbital Hubbard model with increasing interaction strength.

Zig-Zag graphene nanoribbons have edge states that are predicted to be spin-polarized, however, measurement of these spin-polarized states has proved elusive. Here, Brede et al overcome this challenge by growing graphene nanoribbons on ferromagnetic GdAu2, allowing for the direct observation of the spin-polarized edge states.

An Fe^III/V redox mechanism in Li₄FeSbO₆ on delithiation without Fe^IV or oxygen formation with resistance to aging, high operating potential and low voltage hysteresis is demonstrated, with implications for Fe-based high-voltage applications.

Evidence for metal–insulator transitions in dilute 2D electron gases has sparked controversy and debate. A new model suggests such behaviour could arise from strong correlations driven by non-local Coulomb interactions, providing an alternative view to that which considers disorder to be the over-riding influence.

Precision-engineered devices consisting of a linear array of ten quantum dots are used to realize both the trivial and topological phases of the many-body Su–Schrieffer–Heeger model.

The pseudogap phase exhibited by the cuprates is almost as enigmatic as superconductivity in these materials itself. A time-resolved study performed by Cilento et al. suggests that this state can be photoexcited into a transient non-equilibrium state that is more conductive than the equilibrium state.

The optical properties of nanoalloys are complex and difficult to describe. Here, the authors use density functional and Mie theory to calculate the extinction of Au-Co and other nanoalloys of interest for quantum optics, magnetooptics, catalysis, and metamaterials.

Open-shell nanographenes are used to fabricate length-controlled antiferromagnetic spin-1/2 Heisenberg chains. It is revealed that the spin excitation spectra evolve from gapped to gapless following a power-law dependence on chain length, along with the visualization of the standing waves of confined single spinons.

Chiral spin liquids, a topological phase in frustrated quantum spin systems, have been recently very sought-after. Here, Bauer et al.present a model for a Mott insulator on the Kagome lattice with broken time-reversal symmetry exhibiting such a topological phase.

1T-TaS2 possesses complex electronic phase behaviors in transition-metal di-chalcogenides, undergoing several charge-ordered phases before finally into an insulating state of unknown origin. Here, the authors determine its electronic and structural properties experimentally, revealing its origin.

The nature of the relationship between the spin-ordered and superconducting states of the cuprates is a longstanding puzzle. X-ray measurements conducted by Guarise et al. suggest that a continuum model rather than overdamped magnon model provides a more complete picture of the spin spectrum of Bi₂Sr₂CaCu₂O_8+δ.