A scheme to utilize atomlike emitters coupled to nanophotonic waveguides is proposed for the generation of many-body entangled states and for the reversible mapping of these states of matter to photonic states of an optical pulse in the waveguide. Our protocol makes use of decoherence-free subspaces (DFSs) for the atomic emitters with coherent evolution within the DFSs enforced by strong dissipative coupling to the waveguide. By switching from subradiant to superradiant states, entangled atomic states are mapped to photonic states with high fidelity. An implementation using ultracold atoms coupled to a photonic crystal waveguide is discussed.

Synchronization of many coupled oscillators is widely found in nature and has the potential to revolutionize timing technologies. Here, we demonstrate synchronization in arrays of silicon nitride micromechanical oscillators coupled in an all-to-all configuration purely through an optical radiation field. We show that the phase noise of the synchronized oscillators can be improved by almost 10 dB below the phase noise limit for each individual oscillator. These results open a practical route towards synchronized oscillator networks.

Combining classical molecular dynamics simulations and density functional theory calculations, we find that cations block water flow through narrow (6,6)-type carbon nanotubes (CNTs) because of interactions between cations and aromatic rings in CNTs. In wide CNTs, these interactions trap the cations in the interior of the CNT, inducing unexpected open or closed state switching of ion transfer under a strong electric field, which is consistent with experiments. These findings will help to develop new methods to facilitate water and ion transport across CNTs.

We analyze a microscopic mechanism behind the coexistence of a heavy Fermi liquid and geometric frustration in Kondo lattices. We consider a geometrically frustrated periodic Anderson model and demonstrate how orbital fluctuations lead to a Kondo-screened phase in the limit of extreme strong frustration when only local singlet states participate in the low-energy physics. We also propose a setup to realize and study this exotic state with $SU(3)$-symmetric alkaline-earth cold atoms.

We demonstrate that laser excitations can coherently induce a novel Kondo effect in ultracold atoms in optical lattices. Using a model of alkaline-earth fermions with two orbitals, it is shown that the optically coupled two internal states are dynamically entangled to form the Kondo-singlet state, overcoming the heating effect due to the irradiation. Furthermore, a lack of $\mathrm{SU}(N)$ symmetry in the optical coupling provides a peculiar feature in the Kondo effect, which results in spin-selective renormalization of effective masses. We also discuss the effects of interorbital exchange interactions, and reveal that they induce novel crossover or reentrant behavior of the Kondo effect owing to control of the coupling anisotropy. The laser-induced Kondo effect is highly controllable by tuning the laser strength and the frequency, and thus offers a versatile platform to study the Kondo physics using ultracold atoms.

We report the first observation of the polar phase of superfluid ${}^3\mathrm{He}$. This phase appears in ${}^3\mathrm{He}$ confined in a new type of aerogel with a nearly parallel arrangement of strands which play the role of ordered impurities. Our experiments qualitatively agree with theoretical predictions and suggest that in other systems with unconventional Cooper pairing (e.g., in unconventional superconductors) similar phenomena may be found in the presence of anisotropic impurities.

The geometry of electronic bands in a solid can drastically alter single-particle charge and spin transport. We show here that collective optical excitations arising from Coulomb interactions also exhibit unique signatures of Berry curvature and quantum geometric tensor. A nonzero Berry curvature mixes and lifts the degeneracy of $l\ne 0$ states, leading to a time-reversal-symmetric analog of the orbital Zeeman effect. The quantum geometric tensor, on the other hand, leads to $l$-dependent shifts of exciton states that is analogous to the Lamb shift. Our results provide an explanation for the nonhydrogenic exciton spectrum recently calculated for transition-metal dichalcogenides. Numerically, we find a Berry curvature induced splitting of $\sim 10\mathrm{meV}$ between the $2p_x\pm i2p_y$ states of ${\mathrm{WSe}}_2$.

By quantizing the semiclassical motion of excitons, we show that the Berry curvature can cause an energy splitting between exciton states with opposite angular momentum. This splitting is determined by the Berry curvature flux through the $\mathit{k}$-space area spanned by the relative motion of the electron-hole pair in the exciton wave function. Using the gapped two-dimensional Dirac equation as a model, we show that this splitting can be understood as an effective spin-orbit coupling effect. In addition, there is also an energy shift caused by other “relativistic” terms. Our result reveals the limitation of the venerable hydrogenic model of excitons, and it highlights the importance of the Berry curvature in the effective mass approximation.

We report on an exact diagonalization study of fractional quantum Hall states at a filling factor of $\nu =2/3$ in a system with a fourfold degenerate $n=0$ Landau level and SU(4) symmetric Coulomb interactions. Our investigation reveals previously unidentified SU(3) and SU(4) singlet ground states which appear at a flux quantum shift 2 when a spherical geometry is employed and lie outside the established composite-fermion or multicomponent Halperin state patterns. We evaluate the two-particle correlation functions of these states and discuss quantum phase transitions in graphene between singlet states with a different number of components as the magnetic field strength is increased.

${\text{YbMgGaO}}_4$, a structurally perfect two-dimensional triangular lattice with an odd number of electrons per unit cell and spin-orbit entangled effective spin-$1/2$ local moments for the ${\mathrm{Yb}}^{3+}$ ions, is likely to experimentally realize the quantum spin liquid ground state. We report the first experimental characterization of single-crystal ${\text{YbMgGaO}}_4$ samples. Because of the spin-orbit entanglement, the interaction between the neighboring ${\mathrm{Yb}}^{3+}$ moments depends on the bond orientations and is highly anisotropic in the spin space. We carry out thermodynamic and the electron spin resonance measurements to confirm the anisotropic nature of the spin interaction as well as to quantitatively determine the couplings. Our result is a first step towards the theoretical understanding of the possible quantum spin liquid ground state in this system and sheds new light on the search for quantum spin liquids in strong spin-orbit coupled insulators.

The iridate ${\mathrm{Na}}_2{\mathrm{IrO}}_3$ was proposed to be a realization of the Kitaev model with a quantum spin liquid ground state. Experiments have now established that this material hosts a zigzag antiferromagnetic order. However, the previous assignment of the ordered moment direction to the $\mathit{a}$ axis is controversial. We examine the magnetic moment direction of ${\mathrm{Na}}_2{\mathrm{IrO}}_3$ using the local spin density approximation plus spin orbit coupling+U calculations. Our calculations reveal that the total energy is minimized when the zigzag-ordered moments are aligned along $\mathit{g}\approx \mathit{a}+\mathit{c}$ direction. The dependence of the total energy on moment directions can be explained by adding anisotropic interactions to the nearest-neighbor Kitaev-Heisenberg model, on which the spin-wave spectrum is also calculated. The revision of ordered moments is very important to understanding and achieving possible exotic electronic phases in this compound.

We discuss general Maxwell identities relating a macromolecule’s charge, the forces acting at its surface, and the osmotic pressure of the solution in which it sits. The identities are closely related to the contact value relations that hold for certain special geometries, but are more general. In particular, the Maxwell identities can be applied to any macromolecule geometry, and they hold both within and outside of mean-field theory. Examples illustrate that combining the identities with approximate treatments of screening can often return simple, accurate osmotic pressure estimates.

Failure of amorphous solids is fundamental to various phenomena, including landslides and earthquakes. Recent experiments indicate that highly plastic regions form elongated structures that are especially apparent near the maximal shear stress ${\mathrm{\Sigma }}_{\max }$ where failure occurs. This observation suggested that ${\mathrm{\Sigma }}_{\max }$ acts as a critical point where the length scale of those structures diverges, possibly causing macroscopic transient shear bands. Here, we argue instead that the entire solid phase ($\mathrm{\Sigma }<{\mathrm{\Sigma }}_{\max }$) is critical, that plasticity always involves system-spanning events, and that their magnitude diverges at ${\mathrm{\Sigma }}_{\max }$ independently of the presence of shear bands. We relate the statistics and fractal properties of these rearrangements to an exponent $\theta$ that captures the stability of the material, which is observed to vary continuously with stress, and we confirm our predictions in elastoplastic models.

Time-periodic perturbations due to classical electromagnetic fields are useful to engineer the topological properties of matter using the Floquet theory. Here we investigate the effect of quantized electromagnetic fields by focusing on the quantized light-matter interaction on the edge state of a quantum spin Hall insulator. A Dicke-type superradiant phase transition occurs at arbitrary weak coupling, the electronic spectrum acquires a finite gap, and the resulting ground-state manifold is topological with a Chern number of $\pm 1$. When the total number of excitations is conserved, a photocurrent is generated along the edge, being pseudoquantized as $\omega \ln (1/\omega )$ in the low-frequency limit and decaying as $1/\omega$ for high frequencies with $\omega$ the photon frequency. The photon spectral function exhibits a clean Goldstone mode, a Higgs-like collective mode at the optical gap and the polariton continuum.

The flavor composition of high-energy astrophysical neutrinos can reveal the physics governing their production, propagation, and interaction. The IceCube Collaboration has published the first experimental determination of the ratio of the flux in each flavor to the total. We present, as a theoretical counterpart, new results for the allowed ranges of flavor ratios at Earth for arbitrary flavor ratios in the sources. Our results will allow IceCube to more quickly identify when their data imply standard physics, a general class of new physics with arbitrary (incoherent) combinations of mass eigenstates, or new physics that goes beyond that, e.g., with terms that dominate the Hamiltonian at high energy.

Astrophysical neutrinos are powerful tools for investigating the fundamental properties of particle physics through their flavor content. In this Letter, we perform the first general new physics study on ultrahigh energy neutrino flavor content by introducing effective operators. We find that, at the current limits on these operators, new physics terms cause maximal effects on the flavor content; however, the flavor content on the Earth is confined to a region related to the assumed initial flavor content. Furthermore, we conclude that a precise measure of the flavor content on the Earth will provide orders of magnitude improvement on new physics bounds. Finally, we discuss the current best fits of flavor content of the IceCube data and their interplay with new physics scenarios.

We present a fully perturbative mechanism that naturally generates mass hierarchies for the standard model (SM) fermions in a flavor-blind sector. The dynamics generating the mass hierarchies can therefore be independent from the source of flavor violation, and hence this dynamics may operate at a much lower scale. This mechanism works by dynamically enforcing simultaneous diagonalization—alignment—among a set of flavor-breaking spurions, as well as generating highly singular spectra for them. It also has general applications in model building beyond the SM, wherever alignment between exotic and SM sources of flavor violation is desired.