Intriguingly, conducting perovskite interfaces between ordinary band insulators are widely explored, whereas similar interfaces with Mott insulators are still not quite understood. Here, we address the (001), (110), and (111) interfaces between the ${\mathrm{LaTiO}}_3$ Mott, and large band gap ${\mathrm{KTaO}}_3$ insulators. Based on first-principles calculations, we reveal a mechanism of interfacial conductivity, which is distinct from a formerly studied one applicable to interfaces between polar wideband insulators. Here, the key factor causing conductivity is the matching of oxygen octahedra tilting in ${\mathrm{KTaO}}_3$ and ${\mathrm{LaTiO}}_3$ which, due to a small gap in the ${\mathrm{LaTiO}}_3$ results in its sensitivity to the crystal structure, yields metallization of its overlayer and following charge transfer from Ti to Ta. Our findings, also applicable to other Mott insulators interfaces, shed light on the emergence of conductivity observed in ${\mathrm{LaTiO}}_3/{\mathrm{KTaO}}_3$ (110) where the “polar” arguments are not applicable and on the emergence of superconductivity in these structures.

A mobility edge (ME), representing the critical energy that distinguishes between extended and localized states, is a key concept in understanding the transition between extended (metallic) and localized (insulating) states in disordered and quasiperiodic systems. Here we explore the impact of dissipation on a quasiperiodic system featuring MEs by calculating steady-state density matrix and analyzing quench dynamics with sudden introduction of dissipation. We demonstrate that dissipation can lead the system into specific states predominantly characterized by either extended or localized states, irrespective of the initial state. Our results establish the use of dissipation as a new avenue for inducing transitions between extended and localized states and for manipulating dynamic behaviors of particles.

Anyons are particles intermediate between fermions and bosons, characterized by a nontrivial exchange phase, yielding remarkable braiding statistics. Recent experiments have shown that anyonic braiding has observable consequences on edge transport in the fractional quantum Hall effect (FQHE). Here, we study transport signatures of anyonic braiding when the anyons have a finite width. We show that the width of the anyons, even when extremely small, can have a tremendous impact on transport properties and braiding signatures. In particular, we find that taking the finite width into account allows us to explain recent experimental results on the FQHE at filling factor $2/5$ [M. Ruelle et al., Phys. Rev. X 13, 011031 (2023)]. Our work shows that the finite width of anyons crucially influences setups involving anyonic braiding, especially when the exchange phase is larger than $\pi /2$.

We report an efficient temperature modulation of thermal emissivity near room temperature using quantum dots. The quantum confinement effects result in a unique feature that resembles a quasi-two-level electronic system (QTLES). The QTLES’s dielectric function $ϵ(\omega )$ is shown to be dependent on the electron population difference $\delta \rho (T)$, which exhibits strong temperature dependence and can be tuned by adjusting the Fermi-level of the solid. Experiments with the ${\mathrm{Ag}}_2\mathrm{Se}$ quantum dots confirm the theory and showcase a modulate rate $\mathrm{d}\epsilon /\mathrm{d}T\approx 1.5\times {10}^{-3}{\mathrm{K}}^{-1}$ that meets the requirements for engineering applications. This study demonstrates an exciting new avenue for temperature modulation of thermal emission and may open up new possibilities for applications like energy harvesting, thermal camouflage, thermal rectifications, and many others.

Biological tissues transform between solid- and liquidlike states in many fundamental physiological events. Recent experimental observations further suggest that in two-dimensional epithelial tissues these solid-liquid transformations can happen via intermediate states akin to the intermediate hexatic phases observed in equilibrium two-dimensional melting. The hexatic phase is characterized by quasi-long-range (power-law) orientational order but no translational order, thus endowing some structure to an otherwise structureless fluid. While it has been shown that hexatic order in tissue models can be induced by motility and thermal fluctuations, the role of cell division and apoptosis (birth and death) has remained poorly understood, despite its fundamental biological role. Here we study the effect of cell division and apoptosis on global hexatic order within the framework of the self-propelled Voronoi model of tissue. Although cell division naively destroys order and active motility facilitates deformations, we show that their combined action drives a liquid-hexatic-liquid transformation as the motility increases. The hexatic phase is accessed by the delicate balance of dislocation defect generation from cell division and the active binding of disclination-antidisclination pairs from motility. We formulate a mean-field model to elucidate this competition between cell division and motility and the consequent development of hexatic order.

Quanta splitting is an essential generator of Gaussian entanglement, exemplified by Einstein-Podolsky-Rosen states and apparently the most commonly occurring form of entanglement. In general, it results from the strong pumping of a nonlinear process with a highly coherent and low-noise external drive. In contrast, recent experiments involving efficient trilinear processes in trapped ions and superconducting circuits have opened the complementary possibility to test the splitting of a few thermal quanta. Stimulated by such small thermal energy, a strong degenerate trilinear coupling generates large amounts of nonclassicality, detectable by more than 3 dB of distillable quadrature squeezing. Substantial entanglement can be generated via frequent passive linear coupling to a third mode present in parallel with the trilinear coupling. This new form of entanglement, outside any Gaussian approximation, surprisingly grows with the mean number of split thermal quanta; a quality absent from Gaussian entanglement. Using distillable squeezing we shed light on this new entanglement mechanism for nonlinear bosonic systems.

Motivated by an experiment on a superconducting quantum processor [X. Mi et al., Science 378, 785 (2022).], we study level pairings in the many-body spectrum of the random-field Floquet quantum Ising model. The pairings derive from Majorana zero and $\pi$ modes when writing the spin model in Jordan-Wigner fermions. Both splittings have log-normal distributions with random transverse fields. In contrast, random longitudinal fields affect the zero and $\pi$ splittings in drastically different ways. While zero pairings are rapidly lifted, the $\pi$ pairings are remarkably robust, or even strengthened, up to vastly larger disorder strengths. We explain our results within a self-consistent Floquet perturbation theory and study implications for boundary spin correlations. The robustness of $\pi$ pairings against longitudinal disorder may be useful for quantum information processing.

Armed with quantum correlations, quantum sensors in a network have shown the potential to outclass their classical counterparts in distributed sensing tasks such as clock synchronization and reference frame alignment. On the other hand, this analysis was done for simple and idealized networks, whereas the correlation shared within a practical quantum network, captured by the notion of network states, is much more complex. Here, we prove a general bound that limits the performance of using quantum network states to estimate a global parameter, establishing the necessity of genuine multipartite entanglement for achieving a quantum advantage. The bound can also serve as an entanglement witness in networks and can be generalized to states generated by shallow circuits. Moreover, while our bound prohibits local network states from achieving the Heisenberg limit, we design a probabilistic protocol that, once successful, attains this ultimate limit of quantum metrology and preserves the privacy of involved parties. Our work establishes both the limitation and the possibility of quantum metrology within quantum networks.

We study out-of-thermodynamic-equilibrium effects in neutron-star mergers with 3D general-relativistic neutrino-radiation large-eddy simulations. During mergers, the cores of the neutron stars remain cold ($T\sim$ a few MeV) and out of thermodynamic equilibrium with trapped neutrinos originating from the hot collisional interface between the stars. However, within $\sim 2$ to 3 ms matter and neutrinos reach equilibrium everywhere in the remnant massive neutron star. Our results show that dissipative effects, such as bulk viscosity, if present, are only active for a short window of time after the merger.

New calculations for the kinematics of photon decay to fermions in vacuo under an isotropic violation of Lorentz invariance (LV), parametrized by the standard-model extension, are presented in this Letter and used to interpret prompt photon production in LHC data. The measurement of inclusive prompt photon production at the LHC Run 2, with photons observed up to a transverse energy of 2.5 TeV, provides the lower bound ${\tilde{\kappa }}_{\mathrm{tr}}>-1.06\times {10}^{-13}$ on the isotropic coefficient ${\tilde{\kappa }}_{\mathrm{tr}}$ at 95% confidence level. This result improves over the previous bound from hadron colliders by a factor of 55. The calculations for the kinematics of photon decay have further potential use to constrain LV coefficients from the appearance of fermion pairs.

An advanced cooling scheme, incorporating entropy engineering, is vital for isolated artificial quantum systems designed to emulate the low-temperature physics of strongly correlated electron systems. This study theoretically demonstrates a cooling method employing multicomponent Fermi gases with $\mathrm{SU}(\mathcal{N})$-symmetric interactions, focusing on the case of ${}^{173}\mathrm{Yb}$ atoms in a two-dimensional optical lattice. Adiabatically introducing a nonuniform state-selective laser gives rise to two distinct subsystems: a central low-entropy region, exclusively composed of two specific spin components, acts as a quantum simulator for strongly correlated electron systems, while the surrounding $\mathcal{N}$-component mixture retains a significant portion of the entropy of the system. The total particle numbers for each component are good quantum numbers, creating a sharp boundary for the two-component region. The cooling efficiency is assessed through extensive finite-temperature Lanczos calculations. The results lay the foundation for quantum simulations of two-dimensional systems of Hubbard or Heisenberg type, offering crucial insights into intriguing low-temperature phenomena in condensed-matter physics.

The condensation of Rubisco holoenzymes and linker proteins into “pyrenoids,” a crucial supercharger of photosynthesis in algae, is qualitatively understood in terms of “sticker-and-spacer” theory. We derive semianalytical partition sums for small Rubisco-linker aggregates, which enable the calculation of both dilute-phase titration curves and dimerization diagrams. By fitting the titration curves to surface plasmon resonance and single-molecule fluorescence microscopy data, we extract the molecular properties needed to predict dimerization diagrams. We use these to estimate typical concentrations for condensation, and successfully compare these to microscopy observations.

Cosmology offers opportunities to test dark matter independently of its interactions with the standard model. We study the imprints of long-range forces acting solely in the dark sector on the distribution of galaxies, the so-called large scale structure (LSS). We derive the strongest constraint on such forces from a combination of Planck and BOSS data. Along the way we consistently develop, for the first time, the effective field theory of LSS in the presence of new dynamics in the dark sector. We forecast that future surveys will improve the current bound by an order of magnitude.

Angular correlations between heavy quarks provide a unique probe of the quark-gluon plasma created in ultrarelativistic heavy-ion collisions. Results are presented of a measurement of the azimuthal angle correlations between muons originating from semileptonic decays of heavy quarks produced in 5.02 TeV $\mathrm{Pb}+\mathrm{Pb}$ and $pp$ collisions at the LHC. The muons are measured with transverse momenta and pseudorapidities satisfying $p_{\mathrm{T}}^{\mu }>4\mathrm{GeV}$ and $|{\eta }^{\mu }|<2.4$, respectively. The distributions of azimuthal angle separation $\mathrm{\Delta }\varphi$ for muon pairs having pseudorapidity separation $|\mathrm{\Delta }\eta |>0.8$, are measured in different $\mathrm{Pb}+\mathrm{Pb}$ centrality intervals and compared to the same distribution measured in $pp$ collisions at the same center-of-mass energy. Results are presented separately for muon pairs with opposite-sign charges, same-sign charges, and all pairs. A clear peak is observed in all $\mathrm{\Delta }\varphi$ distributions at $\mathrm{\Delta }\varphi \sim \pi$, consistent with the parent heavy-quark pairs being produced via hard-scattering processes. The widths of that peak, characterized using Cauchy-Lorentz fits to the $\mathrm{\Delta }\varphi$ distributions, are found to not vary significantly as a function of $\mathrm{Pb}+\mathrm{Pb}$ collision centrality and are similar for $pp$ and $\mathrm{Pb}+\mathrm{Pb}$ collisions. This observation will provide important constraints on theoretical descriptions of heavy-quark interactions with the quark-gluon plasma.

Harmonic oscillators belong to the most fundamental concepts in physics and are central to many current research fields such as circuit QED, cavity optomechanics, and photon pressure systems. Here, we engineer a microwave mode in a superconducting LC circuit that mimics the dynamics of a negative mass oscillator, and couple it via photon pressure to a second low-frequency circuit. We demonstrate that the effective negative mass dynamics lead to an inversion of dynamical backaction and to sideband cooling of the low-frequency circuit by a blue-detuned pump field, which can be intuitively understood by the inverted energy ladder of a negative mass oscillator.

Non-Hermitian systems can exhibit unique quantum phases without any Hermitian counterparts. For example, the latest theoretical studies predict a new surprising phenomenon that bulk bands can localize and dissipate prominently at the system boundary, which is dubbed the non-Hermitian edge burst effect. Here we realize a one-dimensional non-Hermitian Su-Schrieffer-Heeger lattice with bulk translation symmetry implemented with a photonic quantum walk. Employing time-resolved single-photon detection to characterize the chiral motion and boundary localization of bulk bands, we determine experimentally that the dynamics underlying the non-Hermitian edge burst effect is due to the interplay of non-Hermitian skin effect and imaginary band gap closing. This new non-Hermitian physical effect deepens our understanding of quantum dynamics in open quantum systems.