The precision of a quantum sensor can overcome its classical counterpart when its constituents are entangled. In Gaussian squeezed states, quantum correlations lead to a reduction of the quantum projection noise below the shot noise limit. However, the most sensitive states involve complex non-Gaussian quantum fluctuations, making the required measurement protocol challenging. Here we measure the sensitivity of nonclassical states of the electronic spin $J=8$ of dysprosium atoms, created using light-induced nonlinear spin coupling. Magnetic sublevel resolution enables us to reach the optimal sensitivity of non-Gaussian (oversqueezed) states, well above the capability of squeezed states and about half the Heisenberg limit.

The first ($v_1^{\mathrm{fluc}}$), second ($v_2$), and third ($v_3$) harmonic coefficients of the azimuthal particle distribution at midrapidity are extracted for charged hadrons and studied as a function of transverse momentum ($p_T$) and mean charged particle multiplicity density $⟨N_{\mathrm{ch}}⟩$ in $U+U$ ($\sqrt{s_{NN}}=193\mathrm{GeV}$), $\mathrm{Au}+\mathrm{Au}$, $\mathrm{Cu}+\text{Au}$, $\mathrm{Cu}+\mathrm{Cu}$, $d+\mathrm{Au}$, and $p+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ with the STAR detector. For the same $⟨N_{\mathrm{ch}}⟩$, the $v_1^{\mathrm{fluc}}$ and $v_3$ coefficients are observed to be independent of the collision system, while $v_2$ exhibits such a scaling only when normalized by the initial-state eccentricity (${ϵ}_2$). The data also show that $\ln (v_2/{ϵ}_2)$ scales linearly with $⟨N_{\mathrm{ch}}{⟩}^{-1/3}$. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on $v_n$ from small to large collision systems.

In the tensor network representation, a deformed $Z_2$ topological ground state wave function is proposed and its norm can be exactly mapped to the two-dimensional solvable Ashkin-Teller model. Then the topological (toric code) phase with anyonic excitations corresponds to the partial order phase of the Ashkin-Teller model, and possible topological phase transitions are precisely determined. With the electric-magnetic self-duality, a novel gapless Coulomb state with quasi-long-range order is obtained via a quantum Kosterlitz-Thouless phase transition. The corresponding ground state is a condensate of pairs of logarithmically confined electric charges and magnetic fluxes, and the scaling behavior of various anyon correlations can be exactly derived, revealing the effective interaction between anyons and their condensation. Deformations away from the self-duality drive the Coulomb state into either the gapped Higgs phase or the confining phase.

We report an experimental implementation of tripartite controlled quantum teleportation on quantum optical devices. The protocol is performed through bi- and tripartite entangled channels of discrete variables and qubits encoded in the polarization of individual photons. The experimental results demonstrate successful controlled quantum teleportation with a fidelity around 83%, well above the classical limit. By realizing the controlled quantum teleportation through a biseparable state, we show that tripartite entanglement is not a necessary resource for controlled quantum teleportation, and the controller’s capability to allow or prohibit the teleportation cannot be considered to be a manifestation of tripartite entanglement. These results open new possibilities for further application of controlled quantum teleportation by lowering the teleportation channel’s requirements.

A recent experiment in the Rydberg atom chain observed unusual oscillatory quench dynamics with a charge density wave initial state, and theoretical works identified a set of many-body “scar states” showing nonthermal behavior in the Hamiltonian as potentially responsible for the atypical dynamics. In the same nonintegrable Hamiltonian, we discover several eigenstates at an infinite temperature that can be represented exactly as matrix product states with a finite bond dimension, for both periodic boundary conditions (two exact $E=0$ states) and open boundary conditions (two $E=0$ states and one each $E=\pm \sqrt{2}$). This discovery explicitly demonstrates the violation of the strong eigenstate thermalization hypothesis in this model and uncovers exact quantum many-body scar states. These states show signatures of translational symmetry breaking with a period-2 bond-centered pattern, despite being in one dimension at an infinite temperature. We show that the nearby many-body scar states can be well approximated as “quasiparticle excitations” on top of our exact $E=0$ scar states and propose a quasiparticle explanation of the strong oscillations observed in experiments.

Consider a chaotic dynamical system generating diffusionlike Brownian motion. Consider a second, nonchaotic system in which all particles localize. Let a particle experience a random combination of both systems by sampling between them in time. What type of diffusion is exhibited by this random dynamical system? We show that the resulting dynamics can generate anomalous diffusion, where in contrast to Brownian normal diffusion the mean square displacement of an ensemble of particles increases nonlinearly in time. Randomly mixing simple deterministic walks on the line, we find anomalous dynamics characterized by aging, weak ergodicity breaking, breaking of self-averaging, and infinite invariant densities. This result holds for general types of noise and for perturbing nonlinear dynamics in bifurcation scenarios.

The combination of strong spin-orbit coupling and correlations, e.g., in ruthenates and iridates, has been proposed as a means to realize quantum materials with nontrivial topological properties. We discuss here Mott insulators where on-site spin-orbit coupling favors a local $J_{\mathrm{tot}}=0$ singlet ground state. We investigate excitations into a low-lying triplet, triplons, and find them to acquire nontrivial band topology in a magnetic field. We also comment on magnetic states resulting from triplon condensation, where we find, in addition to the same ordered phases known from the $J_{\mathrm{tot}}=\frac{1}{2}$ Kitaev-Heisenberg model, a triplon liquid taking the parameter space of Kitaev’s spin liquid.

The strong coupling between spin, lattice, and electronic degrees of freedom in magnetic materials can produce interesting phenomena, including multiferroic and magnetodielectric (MD) behavior, and exotic coupled excitations, such as electromagnons. We present a temperature- and magnetic field–dependent inelastic light (Raman) scattering study that reveals the emergence of vibronic modes, i.e., coupled vibrational and crystal-electric-field (CEF) electronic excitations, in the unconventional rare-earth MD material ${\mathrm{Ce}}_2{\mathrm{O}}_3$. The energies and intensities of these emergent vibronic modes are indicative of enhanced vibronic coupling and increased modulation of the dielectric susceptibility in the Néel state ($T_{\mathrm{N}}\approx 6.2\mathrm{K}$). The field dependences of the energies and intensities of these vibronic modes are consistent with a decrease of both the vibronic coupling and the dielectric fluctuations associated with these modes below $T_N$. These results suggest a distinctive mechanism for MD behavior in ${\mathrm{Ce}}_2{\mathrm{O}}_3$ that is associated with a field-tunable coupling between CEF and phonon states.

Measurement-device-independent quantum key distribution (MDI-QKD) can eliminate all detector side channels and it is practical with current technology. Previous implementations of MDI-QKD all used two symmetric channels with similar losses. However, the secret key rate is severely limited when different channels have different losses. Here we report the results of the first high-rate MDI-QKD experiment over asymmetric channels. By using the recent 7-intensity optimization approach, we $\text{demonstrate}>10\times \text{higher}$ key rate than the previous best-known protocols for MDI-QKD in the situation of large channel asymmetry, and extend the secure transmission distance by more than 20–50 km in standard telecom fiber. The results have moved MDI-QKD towards widespread applications in practical network settings, where the channel losses are asymmetric and user nodes could be dynamically added or deleted.

We present an experimental scheme to measure the full distribution of many-body observables in spin systems, both in and out of equilibrium, using an auxiliary qubit as a probe. We focus on the determination of the magnetization and the kink number statistics at thermal equilibrium. The corresponding characteristic functions are related to the analytically continued partition function. Thus, both distributions can be directly extracted from experimental measurements of the coherence of a probe qubit that is coupled to an Ising-type bath, as reported in [X. Peng et al., Phys. Rev. Lett. 114, 010601 (2015)] for the detection of Lee-Yang zeros.

We report on the first computation of the strong running coupling at the physical point (physical pion mass) from the ghost-gluon vertex, computed from lattice simulations with three flavors of domain wall fermions. We find ${\alpha }_{\overline{\mathrm{MS}}}(m_Z^2)=0.1172(11)$, in remarkably good agreement with the world-wide average. Our computational bridge to this value is the Taylor-scheme strong coupling, which has been revealed of great interest by itself because it can be directly related to the quark-gluon interaction kernel in continuum approaches to the QCD bound-state problem.

A recent laser spectroscopy experiment [J. Thielking , Nature, (London) 556, 321 (2018)] has determined for the first time the magnetic dipole moment of the 7.8 eV isomeric state ${}^{229m}\mathrm{Th}$. The measured value differs by a factor of approximately 5 from previous nuclear theory predictions based on the Nilsson model, raising questions about our understanding of the underlying nuclear structure. Here, we present a new theoretical prediction based on a nuclear model with coupled collective quadrupole-octupole and single-particle motions. Our calculations yield an isomer magnetic dipole moment of ${\mu }_{\mathrm{IS}}=-0.35{\mu }_N$ in surprisingly good agreement with the experimentally determined value of $-0.37(6){\mu }_N$, while overestimating the ground state dipole moment by a factor 1.4. The model provides further information on the role and strength of the Coriolis mixing and the most probable value of the gyromagnetic ratio $g_R$ and its consequences for the transition probability $B(M1)$. The key role of the magnetic moment values as constraints in the determination of the isomer decay rates is discussed.

Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at $\sim 250\mathrm{MeV}/\mathrm{nucleon}$ are measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons as compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting, contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei.

The impact of a spherical projectile on an evened-out granular bed generates a uniform ejecta of material and a crater with a raised circular rim. Recently, Sabuwala et al. [Phys. Rev. Lett. 120, 264501 (2018)] found that the uniform blanket of ejecta changes to a set of radial streaks when a spherical body impacts on an undulated granular surface, being a plausible explanation to the enigmatic ray systems on planetary bodies. Here, we show that ray systems can also be generated by the impact of nonspherical projectiles on a flat granular surface. This is a reasonable explanation considering that meteorites are rarely spherical. Moreover, by impacting bodies of different geometries, we show that the crater size follows the same power-law scaling with the impact energy found for spherical projectiles, and the crater rim becomes circular as the impact energy is increased regardless of the projectile shape, which helps to understand why most impact craters in nature are rounded.

An insulator differs from a metal because of a different organization of the electrons in their ground state. In recent years this feature has been probed by means of a geometrical property, the quantum metric tensor, which addresses the system as a whole, and is therefore limited to macroscopically homogenous samples. Here we show that an analogous approach leads to a localization marker, which can detect the metallic versus insulating character of a given sample region using as the sole ingredient the ground state electron distribution, even in the Anderson case (where the spectrum is gapless). When applied to an insulator with a nonzero Chern invariant, our marker is capable of discriminating the insulating nature of the bulk from the conducting nature of the boundary. Simulations (both model Hamiltonian and first principles) on several test cases validate our theory.