We introduce a quantum Monte Carlo inspired reweighting scheme to accurately compute energies from optimally short quantum circuits. This effectively hybrid quantum-classical approach features both entanglement provided by a short quantum circuit, and the presence of an effective nonunitary operator at the same time. The functional form of this projector is borrowed from classical computation and is able to filter out high-energy components generated by a suboptimal variational quantum heuristic Ansatz. The accuracy of this approach is demonstrated numerically in finding energies of entangled ground states of many-body lattice models. We demonstrate a practical implementation on IBM quantum hardware up to an 8-qubit circuit.

We provide a new hydrodynamic framework to describe out-of-equilibrium integrable systems with space-time inhomogeneous interactions. Our result builds up on the recently introduced generalized hydrodynamics (GHD). The method allows us to analytically describe the dynamics during generic space-time-dependent smooth modulations of the interactions. As a proof of concept, we study experimentally motivated interaction quenches in the trapped interacting Bose gas, which cannot be treated with current analytical or numerical methods. We also benchmark our results in the $XXZ$ spin chain and in the classical sinh-Gordon model.

The Kibble-Zurek mechanism predicts the formation of topological defects and other excitations that quantify how much a quantum system driven across a quantum critical point fails to be adiabatic. We point out that, thanks to the divergent linear susceptibility at the critical point, even a tiny symmetry breaking bias can restore the adiabaticity. The minimal required bias scales like ${\tau }_Q^{-\beta \delta /(1+z\nu )}$, where $\beta$, $\delta$, $z$, $\nu$ are the critical exponents and ${\tau }_Q$ is a quench time. We test this prediction by DMRG simulations of the quantum Ising chain. It is directly applicable to the recent emulation of quantum phase transition dynamics in the Ising chain with ultracold Rydberg atoms.

We propose a self-consistency equation for the $\beta$ functions for theories with a large number of flavors, $N$, that exploits all the available information in the Wilson-Fisher critical exponent, $\omega$, truncated at a fixed order in $1/N$. We show that singularities appearing in critical exponents do not necessarily imply singularities in the $\beta$ function. We apply our method to (non-)Abelian gauge theory, where $\omega$ features a negative singularity. The singularities in the $\beta$ function and in the fermion mass anomalous dimension are simultaneously removed providing no hint for a UV fixed point in the large-$N$ limit.

We present a derivation of the holographic dual of logarithmic negativity in ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$ that was recently conjectured in Phys. Rev. D 99, 106014 (2019). This is given by the area of an extremal cosmic brane that terminates on the boundary of the entanglement wedge. The derivation consists of relating the recently introduced Rényi reflected entropy to the logarithmic negativity in holographic conformal field theories. Furthermore, we clarify previously mysterious aspects of negativity at a large central charge seen in conformal blocks and comment on generalizations to generic dimensions, dynamical settings, and quantum corrections.

We show that the Deep Underground Neutrino Experiment (DUNE), with significant but feasible new efforts, has the potential to deliver world-leading results in solar neutrinos. With a $100\mathrm{kton}\text{−}\mathrm{yr}$ exposure, DUNE could detect $\gtrsim {10}^5$ signal events above 5 MeV electron energy. Separate precision measurements of neutrino-mixing parameters and the ${}^8\mathrm{B}$ flux could be made using two detection channels (${\nu }_e+{}^{40}\mathrm{Ar}$ and ${\nu }_{e,\mu ,\tau }+e^{-}$) and the day-night effect ($>10\sigma$). New particle physics may be revealed through the comparison of solar neutrinos (with matter effects) and reactor neutrinos (without), which is discrepant by $\sim 2\sigma$ (and could become $5.6\sigma$). New astrophysics may be revealed through the most precise measurement of the ${}^8\mathrm{B}$ flux (to 2.5%) and the first detection of the hep flux (to 11%). DUNE is required: No other experiment, even proposed, has been shown capable of fully realizing these discovery opportunities.

Electromagnetic radiation with angular frequency equal to half the axion mass stimulates the decay of cold dark matter axions and produces an echo, i.e., faint electromagnetic radiation traveling in the opposite direction. We propose to search for axion dark matter by sending out to space a powerful beam of microwave radiation and listening for its echo. We estimate the sensitivity of this technique in the isothermal and caustic ring models of the Milky Way halo and find it to be a promising approach to axion, or axionlike, dark matter detection.

The $\mathrm{\Lambda }$ ($\overline{\mathrm{\Lambda }}$) hyperon polarization along the beam direction has been measured in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$, for the first time in heavy-ion collisions. The polarization dependence on the hyperons’ emission angle relative to the elliptic flow plane exhibits a second harmonic sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction, expected due to elliptic flow. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum ($p_T$) dependence at $p_T$ greater than $1\mathrm{GeV}/c$. The magnitude of the signal is about 5 times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, the kinematic vorticity calculations in the blast-wave model tuned to reproduce particle spectra, elliptic flow, and the azimuthal dependence of the Gaussian source radii measured with the Hanbury Brown–Twiss intensity interferometry technique reproduce well the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the polarization signal.

We report on the first measurements of $J/\psi$ production at very low transverse momentum ($p_T<0.2\mathrm{GeV}/c$) in hadronic $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ and $\mathrm{U}+\mathrm{U}$ collisions at $\sqrt{s_{NN}}=193\mathrm{GeV}$. Remarkably, the inferred nuclear modification factor of $J/\psi$ at midrapidity in $\mathrm{Au}+\mathrm{Au}$ ($\mathrm{U}+\mathrm{U}$) collisions reaches about 24 (52) for $p_T<0.05\mathrm{GeV}/c$ in the 60%–80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the $dN/dt$ distribution of $J/\psi$ for the very low $p_T$ range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of $J/\psi$ yield observed at extremely low $p_T$ originates from coherent photon-nucleus interactions. In particular, coherently produced $J/\psi$’s in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.

We propose an attosecond extreme ultraviolet pump IR-probe photoionization protocol that employs pairs of counterrotating consecutive harmonics and angularly resolved photoelectron detection, thereby providing a direct measurement of ionization phases. The present method, which we call circular holographic ionization-phase meter, gives also access to the phase of photoemission amplitudes of even-parity continuum states from a single time-delay measurement since the relative phase of one- and two-photon ionization pathways is imprinted in the photoemission anisotropy. The method is illustrated with ab initio simulations of photoionization via autoionizing resonances in helium. The rapid phase excursion in the transition amplitude to both the dipole-allowed $(2s2p){{}^{1}P}^{\mathrm{o}}$ and the dipole-forbidden $(2p^2){{}^{1}D}^{\mathrm{e}}$ states are faithfully reproduced.

Atomic sensing is, at large, based on measuring energy differences. Specifically, magnetometry is typically performed by using a superposition of two quantum states, the energy difference of which depends linearly on the magnetic field due to the Zeeman effect. The magnetic field is then evaluated from repeated measurements of the accumulated dynamic phase between the two Zeeman states. Here we show that atomic clock states, with an energy separation that is independent of the magnetic field, can nevertheless acquire a phase that is magnetic field dependent. We experimentally demonstrate this on an ensemble of optically trapped ${}^{87}\mathrm{Rb}$ atoms. Finally, we use this effect to propose a magnetic field sensing method for static and time-dependent magnetic fields and analyze its sensitivity, showing it essentially allows for high-sensitivity magnetometery.

We consider a binary bosonic condensate with weak mean-field (MF) residual repulsion, loaded in an array of nearly one-dimensional traps coupled by transverse hopping. With the MF force balanced by the effectively one-dimensional attraction, induced in each trap by the Lee-Hung-Yang correction (produced by quantum fluctuations around the MF state), stable on-site- and intersite-centered semidiscrete quantum droplets (QDs) emerge in the array, as fundamental ones and self-trapped vortices, with winding numbers, at least, up to five, in both tightly bound and quasicontinuum forms. The application of a relatively strong trapping potential leads to squeezing transitions, which increase the number of sites in fundamental QDs and eventually replace vortex modes by fundamental or dipole ones. The results provide the first realization of stable semidiscrete vortex QDs, including ones with multiple vorticity.

We introduce a new class of stable light bullets that form in twisted waveguide arrays pumped with ultrashort pulses, where twisting offers a powerful knob to tune the properties of localized states. We find that, above a critical twist, three-dimensional wave packets are unambiguously stabilized, with no minimum energy threshold. As a consequence, when the higher-order perturbations that accompany ultrashort pulse propagation are at play, the bullets dynamically adjust and sweep along stable branches. Therefore, they are predicted to feature an unprecedented experimental robustness.

A wide class of physical systems exhibit scale invariance. While the statistical properties of such behavior can often be investigated by theoretical and experimental means, its dynamics are notoriously hard to parse. We investigate scale-invariant dynamics through an unstable periodic orbit. This orbit coexists with turbulence of an incompressible fluid and yields a significant Kolmogorov energy spectrum. We identify events of intense energy transfer across spatial scales and relate them to vortical dynamics. The results support a recently proposed mechanism for turbulent energy transfer.

The organizing of magnetic skyrmions shows several forms similar to atomic arrays of solid states. Using Lorentz transmission electron microscopy, we report the first direct observation of a stable liquid-crystalline structure of skyrmions in chiral magnet ${\mathrm{Co}}_{8.5}{\mathrm{Zn}}_{7.5}{\mathrm{Mn}}_4(110)$ thin film, caused by magnetic anisotropy and chiral surface twist. Elongated skyrmions are oriented and periodically arranged only in the $⟨110⟩$ directions, whereas they exhibit short-range order along the $⟨001⟩$ directions, indicating a smectic skyrmion state. In addition, skyrmions possess anisotropic interaction with an opposite sign depending on the crystal orientation, in contrast to existing isotropic interaction.

The electric-current stabilized semimetallic state in the quasi-two-dimensional Mott insulator ${\mathrm{Ca}}_2{\mathrm{RuO}}_4$ exhibits an exceptionally strong diamagnetism. Through a comprehensive study using neutron and x-ray diffraction, we show that this nonequilibrium phase assumes a crystal structure distinct from those of equilibrium metallic phases realized in the ruthenates by chemical doping, high pressure, and epitaxial strain, which in turn leads to a distinct electronic band structure. Dynamical mean field theory calculations based on the crystallographically refined atomic coordinates and realistic Coulomb repulsion parameters indicate a semimetallic state with partially gapped Fermi surface. Our neutron diffraction data show that the nonequilibrium behavior is homogeneous, with antiferromagnetic long-range order completely suppressed. These results provide a new basis for theoretical work on the origin of the unusual nonequilibrium diamagnetism in ${\mathrm{Ca}}_2{\mathrm{RuO}}_4$.

We study the orientation statistics of spheroidal, axisymmetric microswimmers, with shapes ranging from disks to rods, swimming in chaotic, moderately turbulent flows. Numerical simulations show that rodlike active particles preferentially align with the flow velocity. To explain the underlying mechanism, we solve a statistical model via the perturbation theory. We show that such an alignment is caused by correlations of fluid velocity and its gradients along particle paths combined with fore-aft symmetry breaking due to both swimming and particle nonsphericity. Remarkably, the discovered alignment is found to be a robust kinematical effect, independent of the underlying flow evolution. We discuss its possible relevance for aquatic ecology.

An integrable model subjected to a periodic driving gives rise generally to a nonintegrable Floquet Hamiltonian. Here we show that the Floquet Hamiltonian of the integrable Lieb-Liniger model in the presence of a linear potential with a periodic time-dependent strength is instead integrable and its quasienergies can be determined using the Bethe ansatz approach. We discuss various aspects of the dynamics of the system at stroboscopic times and we also propose a possible experimental realization of the periodically driven tilting in terms of a shaken rotated ring potential.

We propose that stable boson stars generically fall within an infinite-parameter family of solutions that oscillate on any number of noncommensurate frequencies. We numerically construct two-frequency solutions and explore their parameter space. These solutions merge with the standard boson star family in the limit where the nondominating frequencies are turned off. We find that, for a fixed energy, these two-frequency solutions can differ considerably in size from standard boson stars.