Search

In this work, we consider four $f(R)$ gravity models -- the Hu-Sawicki, Starobinsky, Exponential and Tsujikawa models -- and use a range of cosmological data, together with Markov Chain Monte Carlo sampling techniques, to constrain the associated model parameters. Our main aim is to compare the results we get when $\Omega_{k,0}$ is treated as a free parameter with their counterparts in a spatially flat scenario. The bounds we obtain for $\Omega_{k,0}$ in the former case are compatible with a flat geometry. It appears, however, that a higher value of the Hubble constant $H_0$ allows for more curvature. Indeed, upon including in our analysis a Gaussian likelihood constructed from the local measurement of $H_0$, we find that the results favor an open universe at a little over $1\sigma$. This is perhaps not statistically significant, but it underlines the important implications of the Hubble tension for the assumptions commonly made about spatial curvature. We note that the late-time deviation of the Hubble parameter from its $\Lambda$CDM equivalent is comparable across all four models, especially in the non-flat case. When $\Omega_{k,0}=0$, the Hu-Sawicki model admits a smaller mean value for $\Omega_{\text{cdm},0}h^2$, which increases the said deviation at redshifts higher than unity. We also study the effect of a change in scale by evaluating the growth rate at two different wavenumbers $k_\dagger$. Any changes are, on the whole, negligible, although a smaller $k_\dagger$ does result in a slightly larger average value for the deviation parameter $b$., Comment: 21 pages, 11 figures, 8 tables

International audience; We consider non-Fermi liquids in which the inelastic scattering rate has an intrinsic particle-hole asymmetry and obeys ω/T scaling. We show that, in contrast to Fermi liquids, this asymmetry influences the low-temperature behavior of the thermopower even when the impurity scattering dominates. Implications for the unconventional sign and temperature dependence of the thermopower in cuprates in the strange metal (Planckian) regime are emphasized.

We study the superradiance transition of a two-component three-dimensional Fermi gas interacting with a single-mode light field of Dicke-type coupling. We find that for a noninteracting gas, due to the Fermi blocking, a unique superradiant state with a superradiant outer shell surrounding an inner Fermi sea may appear, and the critical atom-light coupling strength ${g}_{c}$ to trigger the superradiance approaches $\sqrt{{\ensuremath{\omega}}_{c}{E}_{F}/3}$ even for a vanishing transition frequency between a two-spin state (${\ensuremath{\omega}}_{a}\ensuremath{\rightarrow}0$), in contrast to ${g}_{c}\ensuremath{\sim}\sqrt{{\ensuremath{\omega}}_{c}{\ensuremath{\omega}}_{a}}\ensuremath{\rightarrow}0$ for a bosonic or spin system. When the atom-atom attraction is included, we find that the atomic superfluid would compete with the superradiance directly and both orders cannot coexist, giving rise to an interesting ground-state phase diagram with a tricritical point. The resultant phases and phase transitions are characterized by the unique fluctuation spectrum beyond the mean-field level. We further analyze the effects caused by the decay of the light field, which is inevitable for a possible realization in a cavity with a cold atom system. Our results would be beneficial for the understanding of the interplay between Fermi superfluid and superradiance.

Spectrum of the low-lying ${\mathrm{\ensuremath{\Omega}}}_{cc}$ resonances with negative parity, which are assumed to be dominated by $sccq\overline{q}$ pentaquark components, is investigated using the chiral constituent quark model. Energies of the ${\mathrm{\ensuremath{\Omega}}}_{cc}$ resonances are obtained by considering the hyperfine interaction between quarks by exchanging a Goldstone boson. Possible $sccq\overline{q}$ configurations with spin-parity $1/{2}^{\ensuremath{-}}$, $3/{2}^{\ensuremath{-}}$, and $5/{2}^{\ensuremath{-}}$ are taken into account. Numerical results show that the lowest ${\mathrm{\ensuremath{\Omega}}}_{cc}$ resonances with negative parity may lie at $4050\ifmmode\pm\else\textpm\fi{}100\text{ }\text{ }\mathrm{MeV}$. In addition, the transitions of the ${\mathrm{\ensuremath{\Omega}}}_{cc}$ resonance to a pseudoscalar meson and a ground baryon state are also investigated within the chiral Lagrangian approach. We expect that these ${\mathrm{\ensuremath{\Omega}}}_{cc}$ resonances could be observed in the $D{\mathrm{\ensuremath{\Xi}}}_{c}$ channel by future experiments.

We theoretically investigate the ellipticity dependence of high-order harmonic generation in graphene driven by the midinfrared laser field. The ellipticity dependence of the harmonic yield in the experiment [N. Yoshikawa, T. Tamaya, and K. Tanaka, Science 356, 736 (2017)] is reproduced perfectly by solving the semiconductor Bloch equations in the Houston basis under the tight-binding approximation. Based on the semiclassical recollision model, it is found that the recollision distance of the electron-hole pair excited from the zone $0.5{\ensuremath{\omega}}_{0}\ensuremath{\leqslant}\mathrm{\ensuremath{\Delta}}E\ensuremath{\leqslant}2.5{\ensuremath{\omega}}_{0}$ instead of the Dirac points can reach a minimum value at finite ellipticity, which enhances the harmonic yield. In addition, the ellipticity dependence of harmonics can be controlled by varying the chemical potential of graphene. When the chemical potential is decreased to $\ensuremath{-}1.52\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$, the ellipticity dependence of harmonics can transit into the normal behavior. This work uncovers the microscopic mechanism of the ellipticity dependence of the harmonics in graphene and constructs a clear physical picture to understand the unique ellipticity-dependent behaviors in graphene.

We apply a hydrodynamic theory to study transverse magnetosonic resonances in a viscous two-dimensional electron fluid under an in-plane Stern-Gerlach force (SGF), a perpendicular magnetic field with cyclotron frequency ${\ensuremath{\omega}}_{c}$, and an alternating electric field with frequency $\ensuremath{\omega}$. The SGF leads to a splitting in the dispersion curve of the transverse magnetosound wave and hinders the long-wavelength plasmonic excitation. The effective diagonal viscosity coefficient can be enhanced by about one order of magnitude due to the SGF. The variation of absorption power $Y$ with ${\ensuremath{\omega}}_{c}$ exhibits a viscoelastic (VE) resonance at ${\ensuremath{\omega}}_{c}=\ensuremath{\omega}/2$ and transverse magnetosound resonances. The SGF can raise the heights of all resonant peaks and leave the peak positions almost completely unchanged. The most substantial magnetosonic resonant peak, much weaker than the VE peak in the absence of SGF, can be tuned by the SGF to be well above the VE peak. Our results indicate that the SGF can be used to tune the VE resonance and transverse magnetosound resonances, which is relevant to the manipulation of photoresistance and photovoltaic effects in viscous electron fluids.

Using Subaru Hyper Suprime-Cam (HSC) year 1 data, we perform the first $k$-cut cosmic shear analysis constraining both $\Lambda$CDM and $f(R)$ Hu-Sawicki modified gravity. To generate the $f(R)$ cosmic shear theory vector, we use the matter power spectrum emulator trained on COLA (COmoving Lagrangian Acceleration) simulations. The $k$-cut method is used to significantly down-weight sensitivity to small scale ($k > 1 \ h {\rm Mpc }^{-1}$) modes in the matter power spectrum where the emulator is less accurate, while simultaneously ensuring our results are robust to baryonic feedback model uncertainty. We have also developed a test to ensure that the effects of poorly modeled small scales are nulled as intended. For $\Lambda$CDM we find $S_8 = \sigma_8 (\Omega_m / 0.3) ^ {0.5} = 0.789 ^{+0.039}_{-0.022}$, while the constraints on the $f(R)$ modified gravity parameters are prior dominated. In the future, the $k$-cut method could be used to constrain a large number of theories of gravity where computational limitations make it infeasible to model the matter power spectrum down to extremely small scales.

We investigate the anomalous Hall effect in perpendicularly magnetized ferrimagnet $\mathrm{Ni}{\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ epitaxial films 3 to 30 nm thick. We find that the anomalous Hall conductivity ${\ensuremath{\sigma}}_{\mathrm{AHE}}$ has complex relations with the longitudinal electrical conductivity ${\ensuremath{\sigma}}_{\mathrm{xx}}$. When the ${\ensuremath{\sigma}}_{\mathrm{xx}}$ is relatively large (larger than ${10}^{3}\phantom{\rule{0.16em}{0ex}}{\mathrm{\ensuremath{\Omega}}}^{--1}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{--1}$), the ${\ensuremath{\sigma}}_{\mathrm{AHE}}$ is almost independent of the ${\ensuremath{\sigma}}_{\mathrm{xx}}$, but scales with the magnetization. This unique scaling behavior of ${\ensuremath{\sigma}}_{\mathrm{AHE}}$ indicates that the anomalous Hall effect is of intrinsic origin dominated by the Berry curvature of occupied electronic states. On the other hand, when the ${\ensuremath{\sigma}}_{\mathrm{xx}}$ is lowered, the scaling relation is changed to ${\ensuremath{\sigma}}_{\mathrm{AHE}}\ensuremath{\sim}{\ensuremath{\sigma}}_{\mathrm{xx}}^{1.6}$, indicating a crossover of the dominant contribution to ${\ensuremath{\sigma}}_{\mathrm{AHE}}$, from the intrinsic Berry phase to the impurity scatterings. Our results show the intrinsic contribution from Berry curvature plays a crucial role in the anomalous Hall effect in $\mathrm{Ni}{\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ films.

We introduce an axion-inflation model embedded in the left-right symmetric extension of the Standard Model in which ${W}_{R}$ is coupled to the axion. This model merges three milestones of modern cosmology, i.e., inflation, cold dark matter, and baryon asymmetry. Thus, it can naturally explain the observed coincidences among cosmological parameters, i.e., ${\ensuremath{\eta}}_{\mathsf{B}}\ensuremath{\approx}{P}_{\ensuremath{\zeta}}$ and ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{DM}}\ensuremath{\simeq}5{\mathrm{\ensuremath{\Omega}}}_{\mathsf{B}}$. The source of asymmetry is spontaneous $CP$ violation in the physics of inflation, and the lightest right-handed neutrino is the cold dark matter candidate with mass ${m}_{{N}_{1}}\ensuremath{\sim}1\text{ }\text{ }\mathrm{GeV}$. The introduced mechanism does not rely on the largeness of the unconstrained $CP$-violating phases in the neutrino sector or fine-tuned masses for the heaviest right-handed neutrinos. It has two unknown fundamental scales, i.e., scale of inflation ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{inf}}=\sqrt{H{M}_{\mathrm{Pl}}}$ and left-right symmetry breaking ${\mathrm{\ensuremath{\Lambda}}}_{F}$. Sufficient matter asymmetry demands that ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{inf}}\ensuremath{\approx}{\mathrm{\ensuremath{\Lambda}}}_{F}$. Baryon asymmetry and dark matter today are remnants of a pure quantum effect (chiral anomaly) in inflation, which, thanks to flavor effects, has been memorized by cosmic evolution.

We reanalyze the problems in the assignment of $3^{3}{S}_{1}$ and $4^{3}{S}_{1}$ light mesons, which have not yet been well established with the $q\overline{q}$ quark model. Regge trajectories and the $^{3}{P}_{0}$ decay model are used, respectively, to study the mass and width of the observed states and predict the missing ones. By comparing our calculations with the latest experiments, we suggest that the inconsistent data of $\ensuremath{\rho}(2150)$ may include two similar structures, $\ensuremath{\rho}(4{^{3}S}_{1})$ and $\ensuremath{\omega}(4{^{3}S}_{1})$. In addition, the problem of the ${K}^{*}(2{^{3}S}_{1})$ assignment, with two observed states ${K}^{*}(1410)$ and ${K}^{*}(1680)$, is investigated, with several possible explanations.

By using frustration-preserving hard-spin mean-field theory, we investigated the phase-transition dynamics in the three-dimensional field-free $\ifmmode\pm\else\textpm\fi{} J$ Ising spin-glass model. As the temperature $T$ is decreased from paramagnetic phase at high temperatures, with a rate $\ensuremath{\omega}=\ensuremath{-}dT/dt$ in time $t$, the critical temperature depends on the cooling rate through a clear power law ${\ensuremath{\omega}}^{a}$. With increasing antiferromagnetic bond fraction $p$, the exponent $a$ increases for the transition into the ferromagnetic case for $pl{p}_{\text{c}}$ and decreases for the transition into the spin-glass phase for $pg{p}_{\text{c}}$, signaling the ferromagnetic -- spin-glass phase transition at ${p}_{\text{c}}\ensuremath{\approx}0.22$. The relaxation time is also investigated in the adiabatic case $\ensuremath{\omega}=0$ and the dynamic exponent $z\ensuremath{\nu}$ is found to increase with increasing $p$.

We show that photon spheres of supermassive black holes generate high-frequency stochastic gravitational waves through photon-graviton conversion. Remarkably, the frequency is universally determined as ${m}_{e}\sqrt{{m}_{e}/{m}_{p}}\ensuremath{\simeq}{10}^{20}\text{ }\text{ }\mathrm{Hz}$ in terms of the proton mass ${m}_{p}$ and the electron mass ${m}_{e}$. It turns out that the density parameter of the stochastic gravitational waves ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{gw}}$ could be ${10}^{\ensuremath{-}12}$. Since the existence of the gravitational waves from photon spheres is robust, it is worth seeking methods of detecting high-frequency gravitational waves around ${10}^{20}\text{ }\text{ }\mathrm{Hz}$.

Circular dichroism in photoelectron angular distributions of general biharmonic (i.e., $n\ensuremath{\omega}+m\ensuremath{\omega}$) atomic ionization is analyzed theoretically and given along with ``experimental guidelines'' on how it can be steered towards its maximum. It is shown that such a maximum circular dichroism can always be achieved for the ionization of an arbitrary atom and for any incident fundamental photon energy by fine control of only two experimental parameters: the relative flux and phase difference of the two components of the radiation field. In this Letter, we provide a simple analytical description of the circular dichroism as well as a set of rules which enables full control over its magnitude. Our findings are demonstrated explicitly for the ionization of helium with a two-color field composing a fundamental beam and its second harmonic.

We parameterize the second post-Newtonian (2PN) metric for a gravitating system of fluids in the generalized harmonic gauge, and find that there are only three independent 2PN parameters (i.e. $\omega$, $\delta$ and $\delta_2$) for satisfying some conservation laws including the conservations of energy, momentum, angular-momentum and the uniform motion of the center-of-mass., Comment: 17 pages

Surface impedance of type-II superconductors is determined by their local optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega})$. Standard BCS-like theoretical descriptions of $\ensuremath{\sigma}(\ensuremath{\omega})$, due to Mattis and Bardeen [Phys. Rev. 111, 412 (1958)] or Zimmermann et al. [Physica C 183, 99 (1991)], do not take pair-breaking processes into account. Therefore they do not provide a quantitative explanation of the microwave response, and in particular, they cannot predict the magnitude of the coherence peak. Here, based on the recently developed concept of Dynes superconductors, which does take also the pair-breaking scattering into account, we provide a simple but complete description of the microwave response of type-II superconductors, concentrating on the unexpected properties of clean superconductors which are often used as cavity materials.

A search for $CP$ violation in charmless three-body $\Xi_b^- \to p K^- K^-$ decays is performed using $pp$ collision data recorded with the LHCb detector, corresponding to integrated luminosities of $1\,\text{fb}^{-1}$ at a centre-of-mass energy $\sqrt{s} = 7\,\text{TeV}$, $2\,\text{fb}^{-1}$ at $\sqrt{s} = 8\,\text{TeV}$ and $2\,\text{fb}^{-1}$ at $\sqrt{s} = 13\,\text{TeV}$. A good description of the phase-space distribution is obtained with an amplitude model containing contributions from $\Sigma(1385)$, $\Lambda(1405)$, $\Lambda(1520)$, $\Lambda(1670)$, $\Sigma(1775)$ and $\Sigma(1915)$ resonances. The model allows for $CP$-violation effects, which are found to be consistent with zero. The branching fractions of $\Xi_b^- \to \Sigma(1385) K^-$, $\Xi_b^- \to \Lambda(1405) K^-$, $\Xi_b^- \to \Lambda(1520) K^-$, $\Xi_b^- \to \Lambda(1670) K^-$, $\Xi_b^- \to \Sigma(1775) K^-$ and $\Xi_b^- \to \Sigma(1915) K^-$ decays are also reported. In addition, an upper limit is placed on the product of ratios of $\Omega_b^-$ and $\Xi_b^-$ fragmentation fractions and the $\Omega_b^- \to p K^- K^-$ and $\Xi_b^- \to p K^- K^-$ branching fractions.

Transition metal doped ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ with high mobility can be used as a transparent conductor with enhanced transparency spectral window. In this work, we carried out a comprehensive study on the electrical and optical properties of ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ doped with several transition metal (TM) species (${\mathrm{In}}_{2}{\mathrm{O}}_{3}:\mathrm{TM}$) including W, Zr, Mo, and Ti. Detailed optical properties obtained by spectroscopic ellipsometry (SE) are correlated with electrical properties obtained by Hall effect measurements. We find that the mobility of ${\mathrm{In}}_{2}{\mathrm{O}}_{3}:\mathrm{TM}$ thin films lies in the range of $50\text{--}75\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\text{\ensuremath{-}}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\text{\ensuremath{-}}1}$, much higher than the typical mobility of $30\text{--}40\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\text{\ensuremath{-}}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\text{\ensuremath{-}}1}$ for conventional ITO. The complex dielectric functions of the thin films reveal remarkable carrier density dependent changes in the optical properties. SE analyses show that the electron effective mass of ${\mathrm{In}}_{2}{\mathrm{O}}_{3}:\mathrm{TM}$ at the bottom of the conduction band ${m}_{o}^{*}$ ($0.11\text{--}0.14{m}_{o}$) is much smaller than the reported ${m}_{o}^{*}\ensuremath{\sim}0.18\ensuremath{-}0.30{m}_{o}$ for ITO, which directly results in their higher mobility. This low ${m}_{o}^{*}$ is consistent with recent theoretical studies which proposed that $4d$ donor states of the TMs are resonance in the CB. For films with comparably low resistivity of $1\text{--}2\ifmmode\times\else\texttimes\fi{}{10}^{\text{\ensuremath{-}}4}\phantom{\rule{0.16em}{0ex}}\mathrm{\ensuremath{\Omega}}\phantom{\rule{0.16em}{0ex}}\mathrm{cm}$, we find that ${\mathrm{In}}_{2}{\mathrm{O}}_{3}:\mathrm{TM}$ films have \ensuremath{\sim}4--10 times lower absorption coefficient at $\ensuremath{\lambda}=1300\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$ due to free carrier absorption and have their plasma reflection edge extended to \ensuremath{\sim}1.7 \ensuremath{\mu}m compared to \ensuremath{\sim}1.2--1.4 \ensuremath{\mu}m for ITO. Hence, using TM doping we have achieved transparent conductors with conductivity comparable to ITO but with transmission extended to g1600 nm. These materials will be potentially important as transparent conductors for optoelectronic devices utilizing NIR photons.

Finding minimum energy distribution of $N$ charges on a sphere is known as the Thomson problem. Here, we study the vibrational properties of the $N$ charges in the lowest energy state within the harmonic approximation for $10\le N\le 200$ and for selected sizes up to $N=372$. The maximum frequency $\omega_{\rm max}$ increases with $N^{3/4}$, which is rationalized by studying the lattice dynamics of a two-dimensional triangular lattice. The $N$-dependence of $\omega_{\rm max}$ identifies magic numbers of $N=12, 32, 72, 132, 192, 212, 272, 282$, and 372, reflecting both a strong degeneracy of one-particle energies and an icosahedral structure that the $N$ charges form. $N=122$ is not identified as a magic number for $\omega_{\rm max}$ because the former condition is not satisfied. The magic number concept can hold even when an average of high frequencies is considered. The maximum frequency mode at the magic numbers has no anomalously large oscillation amplitude (i.e., not a defect mode)., Comment: 7 pages, 5 figures

The discovery of the hydrodynamic electron liquid (HEL) in graphene [D. Bandurin et al., Science 351, 1055 (2016) and J. Crossno et al., Science 351, 1058 (2016)] has marked the birth of the solid-state HEL which can be probed near room temperature in a table-top setup. Here we examine the terahertz (THz) magneto-optical (MO) properties of a graphene HEL. Considering the case where the magnetic length ${l}_{B}=\sqrt{\ensuremath{\hbar}/eB}$ is comparable to the mean-free path ${l}_{ee}$ for electron-electron interaction in graphene, the MO conductivities are obtained by taking a momentum balance equation approach on the basis of the Boltzmann equation. We find that when ${l}_{B}\ensuremath{\sim}{l}_{ee}$, the viscous effect in a HEL can weaken significantly the THz MO effects such as cyclotron resonance and Faraday rotation. The upper hybrid and cyclotron resonance magnetoplasmon modes ${\ensuremath{\omega}}_{\ifmmode\pm\else\textpm\fi{}}$ are also obtained through the RPA dielectric function. The magnetoplasmons of graphene HEL at large wave-vector regime are affected by the viscous effect, and results in red-shifts of the magnetoplasmon frequencies. We predict that the viscosity in graphene HEL can affect strongly the magneto-optical and magnetoplasmonic properties, which can be verified experimentally.

Using terahertz spectroscopy, we investigate resonant transmission through a dielectric slab with a conducting layer of varied mobility on one side. We observe the well-known Fabry-P\'erot resonances in the transmission. Two fundamentally different regimes of the electrodynamic response of the system are established. In the clean limit, when the radiation frequency exceeds the carrier relaxation rate, $\ensuremath{\omega}\ensuremath{\tau}\ensuremath{\gg}1$, the system exhibits a plasmonic response. As a result, there is a continuous shift in the Fabry-P\'erot resonances with respect to the system parameters. By contrast, in the dirty regime, when $\ensuremath{\omega}\ensuremath{\tau}\ensuremath{\ll}1$, there is an abrupt $\ensuremath{\pi}$ shift in the resonance frequency, as the renormalized film resistance matches the impedance of free space. We find that under this condition, Fabry-P\'erot oscillations disappear entirely over a broad frequency range. Such a matching effect might be of interest in various terahertz applications, for example, involving broadband filters or absorbers.

In this work, we propose the $4S\text{\ensuremath{-}}3D$ mixing scheme to assign the $\mathrm{\ensuremath{\Upsilon}}(10753)$ into the conventional bottomonium family. Under this interpretation, we further study its hidden-bottom hadronic decays with a ${\ensuremath{\eta}}^{(\ensuremath{'})}$ or $\ensuremath{\omega}$ emission, which include $\mathrm{\ensuremath{\Upsilon}}(10753)\ensuremath{\rightarrow}\mathrm{\ensuremath{\Upsilon}}(1S){\ensuremath{\eta}}^{(\ensuremath{'})}$, $\mathrm{\ensuremath{\Upsilon}}(10753)\ensuremath{\rightarrow}{h}_{b}(1P)\ensuremath{\eta}$, and $\mathrm{\ensuremath{\Upsilon}}(10753)\ensuremath{\rightarrow}{\ensuremath{\chi}}_{bJ}\ensuremath{\omega}$ ($J=0$, 1, 2) processes. Since the $\mathrm{\ensuremath{\Upsilon}}(10753)$ is above the $B\overline{B}$ threshold, the coupled-channel effect cannot be ignored; thus, when calculating partial decay widths of these $\mathrm{\ensuremath{\Upsilon}}(10753)$ hidden-bottom decays, we apply the hadronic loop mechanism. Our result shows that these discussed decay processes own considerable branching fractions with an order of magnitude of ${10}^{\ensuremath{-}4}--{10}^{\ensuremath{-}3}$, which can be accessible at Belle II and other future experiments.

We use QCD sum rules to study the mass spectra of $P$-wave charmed baryons of the $SU(3)$ flavor ${\mathbf{6}}_{F}$. We also use light cone sum rules to study their $S$- and $D$-wave decays into ground-state charmed baryons together with light pseudoscalar and vector mesons. We work within the framework of heavy quark effective theory, and we also consider the mixing effect. Our results can explain many excited charmed baryons as a whole, including the ${\mathrm{\ensuremath{\Sigma}}}_{c}(2800{)}^{0}$, ${\mathrm{\ensuremath{\Xi}}}_{c}(2923{)}^{0}$, ${\mathrm{\ensuremath{\Xi}}}_{c}(2939{)}^{0}$, ${\mathrm{\ensuremath{\Xi}}}_{c}(2965{)}^{0}$, ${\mathrm{\ensuremath{\Omega}}}_{c}(3000{)}^{0}$, ${\mathrm{\ensuremath{\Omega}}}_{c}(3050{)}^{0}$, ${\mathrm{\ensuremath{\Omega}}}_{c}(3066{)}^{0}$, ${\mathrm{\ensuremath{\Omega}}}_{c}(3090{)}^{0}$, and ${\mathrm{\ensuremath{\Omega}}}_{c}(3119{)}^{0}$. Their masses, mass splittings within the same multiplets, and decay properties are extracted for future experimental searches.

Statistical modeling of experimental and simulation databases has enabled the development of an accurate predictive capability for deuterium-tritium layered cryogenic implosions at the OMEGA laser [V. Gopalaswamy et al.,Nature 565, 581 (2019)10.1038/s41586-019-0877-0]. In this letter, a physics-based statistical mapping framework is described and used to uncover the dependencies of the fusion yield. This model is used to identify and quantify the degradation mechanisms of the fusion yield in direct-drive implosions on OMEGA. The yield is found to be reduced by the ratio of laser beam to target radius, the asymmetry in inferred ion temperatures from the ℓ=1 mode, the time span over which tritium fuel has decayed, and parameters related to the implosion hydrodynamic stability. When adjusted for tritium decay and ℓ=1 mode, the highest yield in OMEGA cryogenic implosions is predicted to exceed 2×10^{14} fusion reactions.

We revisit the experimental and theoretical status of $B \to \rho l \bar{\nu}$ and $B \to \omega l \bar{\nu}$ decays. We perform a combined fit of averaged spectra from Belle and Babar measurements with prior light cone sum rule calculations, in order to obtain more precise predictions over the full $q^2$ range. The extracted values of $|V_{ub}|$ from these combined fits exhibit smaller uncertainty compared to previous extractions from $B \to \rho l \bar{\nu}$ and $B \to \omega l \bar{\nu}$ decays and the central values are found to be smaller than values extracted from $B \to \pi l \nu$ or inclusive measurements. We use our fit results to obtain more precise predictions in and beyond the Standard Model for the lepton universality ratios $R(\rho)$ and $R(\omega)$, as well as several angular observables that are sensitive to the full $q^2$ distribution, such as the longitudinal polarization of the vector meson, the $\tau$ polarization, and its forward-backward asymmetry.

We evaluate the cross section for the $pp\ensuremath{\rightarrow}pp{f}_{1}(1285)$ and $p\overline{p}\ensuremath{\rightarrow}p\overline{p}{f}_{1}(1285)$ reactions at near threshold energies relevant for the HADES and PANDA experiments at GSI-FAIR. We assume that at energies close to the threshold the $\ensuremath{\omega}\ensuremath{\omega}\ensuremath{\rightarrow}{f}_{1}(1285)$ and ${\ensuremath{\rho}}^{0}{\ensuremath{\rho}}^{0}\ensuremath{\rightarrow}{f}_{1}(1285)$ fusion processes are the dominant production mechanisms. The vertex for the $VV\ensuremath{\rightarrow}{f}_{1}$ coupling is derived from an effective coupling Lagrangian. The ${g}_{\ensuremath{\rho}\ensuremath{\rho}{f}_{1}}$ coupling constant is extracted from the decay rate of ${f}_{1}(1285)\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}\ensuremath{\gamma}$ using the vector-meson-dominance ansatz. We assume ${g}_{\ensuremath{\omega}\ensuremath{\omega}{f}_{1}}={g}_{\ensuremath{\rho}\ensuremath{\rho}{f}_{1}}$, equality of these two coupling constants, based on arguments from the naive quark model and vector-meson dominance. The amplitude for the $VV\ensuremath{\rightarrow}{f}_{1}$ fusion, supplemented by phenomenological vertex form factors for the process, is given. The differential cross sections at energies close to the threshold are calculated. In order to determine the parameters of the model the $\ensuremath{\gamma}p\ensuremath{\rightarrow}{f}_{1}(1285)p$ reaction is discussed in addition and results are compared with the CLAS data. The possibility of a measurement by HADES@GSI is presented and discussed. We perform a Monte Carlo feasibility simulation of the $pp\ensuremath{\rightarrow}pp{f}_{1}$ reaction for $\sqrt{s}=3.46\text{ }\text{ }\mathrm{GeV}$ with the ${f}_{1}$ decaying into the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ (not shown explicitly) and ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\eta}(\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0})$ final states using the PLUTO event generator. The latter ${f}_{1}$ decay is especially promising as a peak in the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\eta}$ mass distribution should be observable by HADES.

We describe and explain two competing regimes of ac magnetic response in current-carrying type-II superconducting wires which were observed experimentally. In the usual regime, voltage $V(t)$, induced by vortex motion across the wire, is ``in phase'' with the external magnetic field $H(t)\ensuremath{\propto}sin(\ensuremath{\omega}t)$. However, as frequency $\ensuremath{\omega}$ grows up or transport current $I$ decreases, an anomalous, ``out-of-phase'' peak in $V(t)$ appears. If these two regimes coexist, then two peaks in voltage are observed per half period of $H(t)$ in both experiment and numerical simulations. At certain combinations of $\ensuremath{\omega}, I$ and the amplitude of the external field, the out-of-phase mechanism even overwhelms the usual, in-phase one. It is shown that the out-of-phase maximum in $V(t)$ is due to the inhibition effect of zero-field (annihilation) lines on flux motion. Such lines, if present in the sample, significantly decelerate magnetic relaxation and dramatically affect the induced voltage. A phase diagram enabling one to distinguish between the in-phase and out-of-phase regimes is constructed.

In this work, we argue that the observed differences in the value of the vector coupling constant extracted from the decays $\rho\to \pi\pi$ ($g_{\rho} = 6.0$), $\rho\to l^+l^-$ ($g_{\rho} = 5.0 $) and $\omega\to l^+ l^-$ ($g_{\rho} = 5.7$), where $l=e,\mu $, are an indication of the important role played by the $1/N_c$ corrections in the description of these processes. We show that an emission of a photon by charged meson loops in the $\rho^0, \omega,\phi\to\gamma$ transitions is a key process that allows to describe above vector meson decays into two leptons with a single value $g_\rho = 6.0$. Our result supports the idea of universality of neutral vector mesons and clarifies the role of accounting of $1/N_c$ corrections to its fulfilment., Comment: 9 pages, 2 figuras, the version accepted for publication in Physical Review D

We analyze dispersion relations of magnons in ferromagnetic nanostructures with uniaxial anisotropy taking into account inertial terms, i.e., magnetic nutation. Inertial effects are parametrized by the damping-independent parameter $\ensuremath{\beta}$, which allows for an unambiguous discrimination of inertial effects from Gilbert damping parameter $\ensuremath{\alpha}$. The analysis of magnon dispersion relation shows its two branches are modified by the inertial effect, albeit in different ways. The upper nutation branch starts at $\ensuremath{\omega}=1/\ensuremath{\beta}$, the lower branch coincides with ferromagnetic resonance (FMR) in the long-wavelength limit and deviates from the zero-inertia parabolic dependence $\ensuremath{\simeq}{\ensuremath{\omega}}_{\text{FMR}}+D{k}^{2}$ of the exchange magnon. Taking a realistic experimental geometry of magnetic thin films, nanowires, and nanodiscs, magnon eigenfrequencies, eigenvectors, and $Q$-factors are found to depend on the shape anisotropy. The possibility of phase-matched magnetoelastic excitation of nutation magnons is discussed and the condition was found to depend on $\ensuremath{\beta}$, exchange stiffness $D$, and the acoustic velocity.

Recently, the BESIII Collaboration reported a resonance $Y(2040)$ with $M=2034\ifmmode\pm\else\textpm\fi{}13\ifmmode\pm\else\textpm\fi{}9\text{ }\text{ }\mathrm{MeV}$ and $\mathrm{\ensuremath{\Gamma}}=234\ifmmode\pm\else\textpm\fi{}30\ifmmode\pm\else\textpm\fi{}25\text{ }\text{ }\mathrm{MeV}$ in the process of ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0}$. In addition, new measurements with much higher precision for the $\ensuremath{\rho}(1900)$ and $\ensuremath{\rho}(2150)$ states are obtained by the BESIII and BABAR Collaborations. In this work, we perform a systematic study on the mass spectrum of the excited $\ensuremath{\rho}$ resonances using the modified Godfrey-Isgur model, and the strong decays of $Y(2040)$, $\ensuremath{\rho}(1900)$, and $\ensuremath{\rho}(2150)$ within the $^{3}{P}_{0}$ model. We find that $Y(2040)$, $\ensuremath{\rho}(1900)$, and $\ensuremath{\rho}(2150)$ can be interpreted as the $\ensuremath{\rho}(2{^{3}D}_{1})$, $\ensuremath{\rho}(3{^{3}S}_{1})$, and $\ensuremath{\rho}(4{^{3}S}_{1})$ states, respectively. Meanwhile, the mass and strong decays of the $\ensuremath{\rho}(3{^{3}D}_{1})$ state are predicted as well, which could be helpful to search for this state in the future.

This paper reports diffused metal-insulator transitions (MITs) in an oxide with disorder that undergoes a Mott transition. The investigation was carried out in the multilayer film ${\text{NdNiO}}_{3}/{\text{BaTiO}}_{3}/{\text{SrTiO}}_{3}$ (NNO/BTO/STO), where a large mismatch of lattice constants of NNO with those of BTO leads to strain relaxation and creation of quenched disorder in the NNO film. NNO film in the NNO/BTO/STO multilayer structure shows a broad Mott-type MIT at a temperature ${T}_{\text{MI}}=160\phantom{\rule{0.16em}{0ex}}\text{K}$ from a high-temperature bad metallic phase ($\frac{1}{{\ensuremath{\rho}}_{\text{DC}}}\frac{d{\ensuremath{\rho}}_{\text{DC}}}{dT}l0$) with a high value of resistivity ${\ensuremath{\rho}}_{\text{DC}}\ensuremath{\approx}70 \mathrm{m}\mathrm{\ensuremath{\Omega}}$ cm at 300 K to a low temperature insulating phase. Using noise spectroscopy and impedance spectroscopy which can probe the dynamics of the coexisting phases near the MIT, it was observed that in addition to the MIT at ${T}_{\text{MI}}=160\phantom{\rule{0.16em}{0ex}}\text{K}$, there exists a characteristic temperature ${T}_{G}\ensuremath{\approx}230\phantom{\rule{0.16em}{0ex}}\text{K}$ well above the ${T}_{\text{MI}}$, where large low-frequency correlated fluctuations appear, signifying the appearance of a phase with slow dynamics. ${T}_{G}$ signals the onset of a temperature region ${T}_{\text{MI}}lTl{T}_{G}$ with coexisting phases that have been corroborated by the impedance spectroscopy and AC conductivity measurements. It is suggested that the temperature ${T}_{G}$ may signify the onset of an electronic Griffiths phase that has been theoretically proposed for Mott transitions with disorder.

The $R$-matrix analysis of $A=5$ nuclear systems has been partially validated by applying the technique to the $^{5}\mathrm{Li}$ system and comparing the predicted $\ensuremath{\gamma}$-ray spectrum with historical data. $R$-matrix analysis of the similar $^{5}\mathrm{He}$ system was then used to predict the $\ensuremath{\gamma}$-ray spectral shape for the deuterium-tritium (DT) reaction. The resulting spectra have been used in the analysis of DT implosions on the Omega laser where the $\ensuremath{\gamma}$-ray interaction rate was measured by a gas Cherenkov detector. Comparison of predictions to experiment confirmed the presence of both 16.75 and $\ensuremath{\approx}13$ MeV $\ensuremath{\gamma}$-ray contributions; analysis, using $R$-matrix spectra, yielded a ratio of $\ensuremath{\gamma}$-ray emission from a transition to the intermediate excited state to that from a transition to the ground state of $(2.1\ifmmode\pm\else\textpm\fi{}0.4):1$, substantiating the first spectral measurement of the DT fusion $\ensuremath{\gamma}$ ray in an inertial fusion environment.

In this work we have reexamined the shape isomer in $^{235}\mathrm{U}$. Reanalyzing data from a previous experiment gave a half-life of ${T}_{1/2}=(11\ifmmode\pm\else\textpm\fi{}3)\phantom{\rule{4pt}{0ex}}\mathrm{ms}$ and a cross section for populating the isomer of ${\ensuremath{\sigma}}_{\mathrm{iso}}=(12\ifmmode\pm\else\textpm\fi{}1)\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{b}$. Combining these new results with measured properties of fission fragments from the reaction $^{234}\mathrm{U}(n,f)$ allowed extracting parameters describing the outer fission barrier. The deduced barrier parameters are ${E}_{B}=(5.7\ifmmode\pm\else\textpm\fi{}0.6)$ MeV and $\ensuremath{\hbar}{\ensuremath{\omega}}_{B}=(0.5\ifmmode\pm\else\textpm\fi{}0.1)$ MeV for the height and curvature, respectively, as well as the energy of the superdeformed ground state ${E}_{II}=(2.4\ifmmode\pm\else\textpm\fi{}0.6)$ MeV. Separate barrier parameters for the standard-1 and standard-2 fission modes have been estimated, too. Finally, the results obtained in this work have been successfully tested for their plausibility.

Laser-direct-drive symmetric implosions on OMEGA illuminate a target with 60 laser beams and are designed to produce spherical implosions. Each beam is smoothed using orthogonal polarizations obtained by passing the laser beams through distributed polarization rotators (DPRs). Observations of light scattered from OMEGA implosions do not show the expected symmetry and have much larger variation than standard predictions. For the first time, we have quantified the scattered-light nonuniformity from individual beams and identified the DPRs as the source of the enhanced nonuniformity. An instrument was invented that isolated and measured the variation in the intensity and polarization of the light scattered from each OMEGA beam. The asymmetric intensity and polarization measurements are explained when the on-target offsets between the two orthogonal polarizations produced by the DPRs are modeled using a 3D cross-beam energy transfer (CBET) code that tracks the polarizations of each beam. The time-integrated nonuniformity in laser absorption and scattered light due to CBET and the DPR polarization offsets during high-performance OMEGA implosions is predicted to be significant and dominated by low spherical harmonic mode numbers. The nonuniformity is predicted to be greatly reduced by replacing the DPRs with new optics that create smaller offsets.

At large virtuality $Q^2$, the coupling to the $\rho$ meson production channels provides us with a natural explanation of the surprisingly large cross section of the $\omega$, as well as the $\pi^+$, meson electroproduction recently measured at backward angles, without destroying the good agreement between the Regge pole model and the data at the real photon point. Together with elastic re-scattering of the outgoing meson it also provides us with a way to explain why the node, that appears at $u\sim -0.15$ GeV$^2$ at the real photon point, disappears at moderate virtuality $Q^2$. Predictions are given for the electroproduction of the $\pi^0$ meson., Comment: 14 pages, 19 figures. Version in press in Phys. Rev. C. A few slips corrected. Figure 11 frame customized References 10 and 14 corrected

Gravitational wave echoes from black holes have been suggested as a crucial observable to probe the spacetime in the vicinity of the horizon. In particular, it was speculated that the echoes are closely connected with specific characteristics of the exotic compact objects, and moreover, possibly provide an access to the quantum nature of gravity. Recently, it was shown that the discontinuity in the black hole metric substantially modifies the asymptotical behavior of quasinormal frequencies. In the present study, we proceed further and argue that a discontinuity planted into the metric furnishes an alternative mechanism for the black hole echoes. Physically, the latter may correspond to an uneven matter distribution inside the surrounding halo. To demonstrate the results, we first numerically investigate the temporal evolution of the scalar perturbations around a black hole that possesses a nonsmooth effective potential. It is shown that the phenomenon persists even though the discontinuity can be located further away from the horizon with rather insignificant strength. Besides, we show that the echoes in the present model can be derived analytically based on the modified pole structure of the associated Green function. The asymptotical properties of the quasinormal mode spectrum and the echoes are found to be closely connected, as both features can be attributed to the same origin. In particular, the period of the echoes in the time domain $T$ is shown to be related to the asymptotic spacing between successive poles along the real axis in the frequency domain $\mathrm{\ensuremath{\Delta}}(\ensuremath{\mathfrak{R}}\ensuremath{\omega})$ by a simple relation ${\mathrm{lim}}_{\ensuremath{\mathfrak{R}}\ensuremath{\omega}\ensuremath{\rightarrow}+\ensuremath{\infty}}\mathrm{\ensuremath{\Delta}}(\ensuremath{\mathfrak{R}}\ensuremath{\omega})=2\ensuremath{\pi}/T$. Moreover, we discuss possible distinguishment between different echo mechanisms. The potential astrophysical implications of the present findings are also addressed.

The recently updated parity doublet structures in $^{223}\mathrm{Th}$ are investigated by using the reflection-asymmetric triaxial particle rotor model. The calculated results well reproduce the available data of the energy spectra and the $B(E1)/B(E2)$ ratios for both medium spin region and the newly established higher spin region, as well as the average value of $B(M1)/B(E2)$ for spins $9/2\ensuremath{\hbar}$ and $11/2\ensuremath{\hbar}$ in the positive-parity band. The main components of the intrinsic wave functions are analyzed to investigate the intrinsic wave functions and their evolutions with spin. The parity doublet bands are mainly based on a single neutron configuration, in which the largest component of the intrinsic wave function is $\ensuremath{\nu}({g}_{9/2},{j}_{15/2})[\mathrm{\ensuremath{\Omega}}=5/2]$ and the second largest one is $\ensuremath{\nu}({g}_{9/2},{j}_{15/2})[\mathrm{\ensuremath{\Omega}}=3/2]$. The amplitude of the largest component decreases whereas the second largest one increases with increasing spin, and the signature splitting behavior for the parity doublet bands could be understood by the variation of these main components with spin.

A Dirac-Fermi liquid (DFL)--a doped system with Dirac spectrum--is an important example of a non-Galilean-invariant Fermi liquid (FL). Real-life realizations of a DFL include, e.g., doped graphene, surface states of three-dimensional (3D) topological insulators, and 3D Dirac/Weyl metals. We study the optical conductivity of a DFL arising from intraband electron-electron scattering. It is shown that the effective current relaxation rate behaves as $1/\tau_{J}\propto \left(\omega^2+4\pi^2 T^2\right)\left(3\omega^2+8\pi^2 T^2\right)$ for $\max\{\omega, T\}\ll \mu$, where $\mu$ is the chemical potential, with an additional logarithmic factor in two dimensions. In graphene, the quartic form of $1/\tau_{J}$ competes with a small FL-like term, $\propto\omega^2+4\pi^2 T^2$, due to trigonal warping of the Fermi surface. We also calculated the dynamical charge susceptibility, $\chi_\mathrm{c}({\bf q},\omega)$, outside the particle-hole continua and to one-loop order in the dynamically screened Coulomb interaction. For a 2D DFL, the imaginary part of $\chi_\mathrm{c}({\bf q},\omega)$ scales as $q^2\omega\ln|\omega|$ and $q^4/\omega^3$ for frequencies larger and smaller than the plasmon frequency at given $q$, respectively. The small-$q$ limit of $\mathrm{Im} \chi_\mathrm{c}({\bf q},\omega)$ reproduces our result for the conductivity via the Einstein relation., Comment: 28 pages, 10 figures

We calculate the density-density response function of biased twisted bilayer graphene (BTBG) and study its plasmon dispersion within the random phase approximation (RPA). At long wavelengths ($q\ensuremath{\rightarrow}0$), plasmon dispersion shows local classical behavior $\ensuremath{\omega}={\ensuremath{\omega}}_{0}\sqrt{q}$. Unlike the situation in conventional two-dimensional electron gas (2DEG), where the density dependence of the plasmon energy is of the form ${\ensuremath{\omega}}_{0}\ensuremath{\propto}\sqrt{n}$ ($n$ is the carrier concentration), the plasmon energy ${\ensuremath{\omega}}_{0}$ is independent of the carrier concentration ($n$) in biased twisted bilayer graphene. Furthermore, the plasmon energy (${\ensuremath{\omega}}_{0}$) is also independent of the Fermi energy ($\ensuremath{\mu}$) which is decided by the carrier concentration ($n$).

We use the functional renormalization approach for quantum spin systems developed by Krieg and Kopietz [Phys. Rev. B $\mathbf{99}$, 060403(R) (2019)] to calculate the spin-spin correlation function $G (\boldsymbol{k}, \omega )$ of quantum Heisenberg magnets at infinite temperature. For small wavevectors $\boldsymbol{k} $ and frequencies $\omega$ we find that $G ( \boldsymbol{k}, \omega )$ assumes in dimensions $d > 2$ the diffusive form predicted by hydrodynamics. In three dimensions our result for the spin-diffusion coefficient ${\cal{D}}$ is somewhat smaller than previous theoretical predictions based on the extrapolation of the short-time expansion, but is still about $30 \%$ larger than the measured high-temperature value of ${\cal{D}}$ in the Heisenberg ferromagnet Rb$_2$CuBr$_4\cdot$2H$_2$O. In reduced dimensions $d \leq 2$ we find superdiffusion characterized by a frequency-dependent complex spin-diffusion coefficient ${\cal{D}} ( \omega )$ which diverges logarithmically in $d=2$, and as a power-law ${\cal{D}} ( \omega ) \propto \omega^{-1/3}$ in $d=1$. Our result in one dimension implies scaling with dynamical exponent $z =3/2$, in agreement with recent calculations for integrable spin chains. Our approach is not restricted to the hydrodynamic regime and allows us to calculate the dynamic structure factor $S ( \boldsymbol{k} , \omega )$ for all wavevectors. We show how the short-wavelength behavior of $S ( \boldsymbol{k}, \omega )$ at high temperatures reflects the relative sign and strength of competing exchange interactions., Comment: 30 pages, 11 figures

The transverse momentum spectra of seven identified hadrons produced in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{{s}_{NN}}=2.76$ and 5.02 TeV at the CERN Large Hadron Collider have been investigated in the framework of the recombination model (RM). Soft, semihard, and hard partons all play important roles in our model and are uniformly treated for all hadrons produced. The investigation has been extended to noncentral collisions and the parameters controlling the momentum degradation of semihard partons have been tuned. Our study shows good agreement between theoretical results and experimental data. To be able to provide a coherent explanation for the production of all identified hadrons ($\ensuremath{\pi}, p, K, \mathrm{\ensuremath{\Lambda}}, \ensuremath{\phi}, \mathrm{\ensuremath{\Xi}}, \mathrm{\ensuremath{\Omega}}$) for transverse momenta as high as 14 $\mathrm{GeV}/c$ (for $\ensuremath{\pi}, p$, and $K$), and for all centralities, is an unprecedented achievement that supports the RM as a sensible model to combine various mechanisms of parton production with a universal scheme of hadronization.

In multiphoton ionization of atoms, elliptical dichroism may arise in the photoelectron angular distributions due to the interference of the possible ionization pathways. We here consider the interaction of atoms with an elliptically polarized biharmonic ($\ensuremath{\omega} + 2\ensuremath{\omega}$) field which simultaneously allows one- and two-photon ionization of the atoms. The interference between these two ionization pathways introduces contributions to the elliptical dichroism in addition to the dichroism that arises from the two-photon ionization alone. We show that these additional dichroism contributions can lead to a stronger dichroism in comparison to the one arising from two-photon ionization only. We present a relativistic analysis of the corresponding photoelectron angular distributions and discuss individual contributions to the dichroic phenomena. Detailed computations have been performed for biharmonic ionization of neutral helium atoms.

The masses of ground and excited states of ${\mathrm{\ensuremath{\Omega}}}_{c}^{0}$, ${\mathrm{\ensuremath{\Omega}}}_{cc}^{+}$, and ${\mathrm{\ensuremath{\Omega}}}_{ccc}^{*++}$ baryons are calculated within the framework of Regge phenomenology. Here our attempt is to assign a possible spin parity to these obtained masses. Our calculated masses in the $(J,{M}^{2})$ plane with both natural (${J}^{P}=1/{2}^{+},3/{2}^{\ensuremath{-}},5/{2}^{+},\dots{}$) and unnatural (${J}^{P}=3/{2}^{+},5/{2}^{\ensuremath{-}},7/{2}^{+},\dots{}$) spin parities are in agreement with the experimental observations where available and reasonably close to other theoretical predictions. Further, we fix the slope and intercept of each Regge line in the $(n,{M}^{2})$ plane and estimate the masses of higher excited states of these baryons. The obtained mass relations and the mass value predictions could provide useful information in future experimental searches and the spin-parity assignment of these states.

In this study, we investigate the cyclotron resonance effect in the first-order ac current, magnetic ratchet effect, and second harmonic generation in phosphorene in the presence of a steady tilted magnetic field and under THz laser radiation. We establish that various cyclotron resonances exist in the deduced currents based on the angular frequency of the incoming light. These resonances are dependent on the ${\ensuremath{\omega}}_{{c}_{+}}$ value, a function of the carrier charge, the perpendicular magnetic field, and the effective masses along the armchair or zigzag edges. We discuss the direction and the magnitude of the deduced currents for various radiation polarizations. We compare the results with a zero perpendicular magnetic field. Cyclotron resonance for the first-order ac current occurs at $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}{\ensuremath{\omega}}_{{c}_{+}}$. The deduced current declines if the perpendicular magnetic field is zero. Meanwhile, for the ratchet current, cyclotron resonances occur at $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}{\ensuremath{\omega}}_{{c}_{+}}$, $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}2{\ensuremath{\omega}}_{{c}_{+}}$, and radiation helicity affects the deduced current for circularly polarized light. Cyclotron resonance for the second harmonic generation current occurs at $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}{\ensuremath{\omega}}_{{c}_{+}}$, $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}2{\ensuremath{\omega}}_{{c}_{+}}$, and $\ensuremath{\omega}=\ifmmode\pm\else\textpm\fi{}{\ensuremath{\omega}}_{{c}_{+}}/2$, and the current is stronger compared to the case with no perpendicular magnetic field. As the magnetic field rotates in the plane of anisotropic phosphorene, separate directions are predicted for the second harmonic generation--related current. It is noteworthy that the magnitude of the ratchet and second harmonic generation current are within the same range and comparable to the magnetic ratchet current in monolayer graphene, $\ensuremath{\mu}\text{A/cm}$.

The dynamic magnetic susceptibility, $\ensuremath{\chi}(\ensuremath{\omega})$, of a model ferrofluid at a very low concentration (volume fraction, approximately $0.05%$), and with a range of dipolar coupling constants ($1\ensuremath{\le}\ensuremath{\lambda}\ensuremath{\le}8$), is examined using Brownian dynamics simulations. With increasing $\ensuremath{\lambda}$, the structural motifs in the system change from unclustered particles, through chains, to rings. This gives rise to a nonmonotonic dependence of the static susceptibility $\ensuremath{\chi}(0)$ on $\ensuremath{\lambda}$ and qualitative changes to the frequency spectrum. The behavior of $\ensuremath{\chi}(0)$ is already understood, and the simulation results are compared to an existing theory. The single-particle rotational dynamics are characterized by the Brownian time, ${\ensuremath{\tau}}_{B}$, which depends on the particle size, carrier-liquid viscosity, and temperature. With $\ensuremath{\lambda}\ensuremath{\le}5.5$, the imaginary part of the spectrum, ${\ensuremath{\chi}}^{\ensuremath{'}\ensuremath{'}}(\ensuremath{\omega})$, shows a single peak near $\ensuremath{\omega}\ensuremath{\sim}{\ensuremath{\tau}}_{B}^{\ensuremath{-}1}$, characteristic of single particles. With $\ensuremath{\lambda}\ensuremath{\ge}5.75$, the spectrum is dominated by the low-frequency response of chains. With $\ensuremath{\lambda}\ensuremath{\ge}7$, new features appear at high frequency, which correspond to intracluster motions of dipoles within chains and rings. The peak frequency corresponding to these intracluster motions can be computed accurately using a simple theory.

Optical microcavities and metallic nanostructures have been shown to significantly modulate the dynamics and spectroscopic response of molecular systems. We present a study of the nonlinear optics of a model consisting of $N$ anharmonic multilevel systems (e.g., Morse oscillators) undergoing collective strong coupling with a resonant infrared microcavity. We find that, under experimentally accessible conditions, molecular systems in microcavities may have nonlinear phenomena significantly intensified due to the high quality of polariton resonances and the enhanced microcavity electromagnetic energy density relative to free space. Particularly large enhancement of multiphoton absorption happens when multipolariton states are resonant with bare molecule multiphoton transitions. In particular, our model predicts two-photon absorption cross-section enhancements by several orders of magnitude relative to free space when the Rabi splitting ${\mathrm{\ensuremath{\Omega}}}_{R}$ is approximately equal to the molecular anharmonic shift $2\mathrm{\ensuremath{\Delta}}$. Our results provide rough upper bounds to resonant nonlinear-response enhancement factors as relaxation to dark states is treated phenomenologically. Notably, ensembles of two-level systems undergoing strong coupling with a cavity (described by the Tavis-Cummings model) show no such optical nonlinearity enhancements, highlighting the rich phenomenology afforded by multilevel anharmonic systems. Similar conclusions are expected to hold for excitonic systems that share features with our model (e.g., molecular dyes with accessible ${S}_{0}\ensuremath{\rightarrow}{S}_{1}\ensuremath{\rightarrow}{S}_{2}$ transitions) and strongly interact with a UV-visible cavity.

Matrix elements of observables in eigenstates of generic Hamiltonians are described by the Srednicki ansatz within the eigenstate thermalization hypothesis (ETH). We study a quantum chaotic spin-fermion model in a one-dimensional lattice, which consists of a spin-1/2 XX chain coupled to a single itinerant fermion. In our study, we focus on translationally invariant observables including the charge and energy current, thereby also connecting the ETH with transport properties. Considering observables with a Hilbert-Schmidt norm of one, we first perform a comprehensive analysis of ETH in the model taking into account latest developments. A particular emphasis is on the analysis of the structure of the offdiagonal matrix elements $|\langle \alpha | \hat O | \beta \rangle|^2$ in the limit of small eigenstate energy differences $\omega = E_\beta - E_\alpha$. Removing the dominant exponential suppression of $|\langle \alpha | \hat O | \beta \rangle|^2$, we find that: (i) the current matrix elements exhibit a system-size dependence that is different from other observables under investigation, (ii) matrix elements of several other observables exhibit a Drude-like structure with a Lorentzian frequency dependence. We then show how this information can be extracted from the autocorrelation functions as well. Finally, our study is complemented by a numerical analysis of the fluctuation-dissipation relation for eigenstates in the bulk of the spectrum. We identify the regime of $\omega$ in which the well-known fluctuation-dissipation relation is valid with high accuracy for finite systems., Comment: v3: Data shown in figures now available as ancillary files

It was observed recently [Shigekawa et al., PNAS 116, 2470 (2019)] that while monolayer iron chalcigenide FeSe on a ${\text{SrTiO}}_{3}$ (STO) substrate has a very high critical temperature, its chemical and structural twin material FeS/STO has a very low ${T}_{c}$, if any. To explain this, the substrate interfacial phonon model of superconductivity in iron chalcogenides is further developed. The main glue is the oxygen ion ${\mathrm{\ensuremath{\Omega}}}_{s}=60\phantom{\rule{0.16em}{0ex}}\text{meV}$ vibrations longitudinal optical (LO) mode. The mode propagates mainly in the ${\text{TiO}}_{2}$ layer adjacent to the monolayer (and also generally present in similar highly polarized ionic crystals like ${\text{BaTiO}}_{3},$ rutile, and anatase). It has stronger electron-phonon coupling to electron gas in FeSe than a well-known ${\mathrm{\ensuremath{\Omega}}}_{h}=100\phantom{\rule{0.16em}{0ex}}\text{meV}$ harder LO mode. It is shown that while (taking into account screened Coulomb repulsion effects) the critical temperature of FeSe on STO and ${\text{TiO}}_{2}$ is above $65\phantom{\rule{0.16em}{0ex}}\text{K}$, it becomes less than $5\phantom{\rule{0.16em}{0ex}}\text{K}$ for FeS due to two factors suppressing the electron-phonon coupling. The effective mass in the latter is twice smaller and, in addition, the distance between the electron gas in FeSe to the vibrating substrate oxygen atoms is 15% smaller than in FeS, reducing the central peak in electron-phonon interaction. The theory is extended to other ionic insulating substrates.

$\ensuremath{\gamma}$-ray emission from $^{12}\mathrm{C}$ and $^{13}\mathrm{C}$ samples irradiated with deuterium-tritium fusion neutrons was experimentally measured at the Omega Laser Facility and at the Ohio University Edwards Accelerator Laboratory. The intent of these measurements was to determine the feasibility of using $^{13}\mathrm{C}$-based plastic ablators with embedded $^{12}\mathrm{C}$ layers for ``dark mix'' diagnosis of inertial confinement fusion implosions. Spectrally resolved measurements at Ohio University identified significant 4.44-MeV $\ensuremath{\gamma}$-ray emission from the $^{13}\mathrm{C}(n,2n\ensuremath{\gamma})^{12}\mathrm{C}$-L1 reaction channel. The recorded 4.44-MeV $^{13}\mathrm{C}$ signal was compared against emission from an identically irradiated $^{12}\mathrm{C}$ target with known $^{12}\mathrm{C}$($n,{n}^{\ensuremath{'}}\ensuremath{\gamma})^{12}\mathrm{C}$-L1 cross section, which resulted in an average $^{13}\mathrm{C}(n,2n\ensuremath{\gamma})^{12}\mathrm{C}$-L1 cross section of 117 $\ifmmode\pm\else\textpm\fi{}$ 17 mb over the incident neutron energy distribution range from 14.4 to 15.8 MeV. Integrated $^{13}\mathrm{C}$ $\ensuremath{\gamma}$-ray signals above 2.9 MeV recorded with the Gas Cherenkov Detector at Omega exceeded MCNP6.1 predictions by a factor of 3. The additional signal was attributed to 4.44-MeV $\ensuremath{\gamma}\mathrm{s}$ resulting in an inferred $^{13}\mathrm{C}(n,2n\ensuremath{\gamma})^{12}\mathrm{C}$-L1 cross section of $95\ifmmode\pm\else\textpm\fi{}11$ mb at 14.1-MeV average incident neutron energy. As a result, the $^{13}\mathrm{C}$-based ``dark mix'' diagnostic concept was deemed infeasible.

We propose a novel method to detect cosmic magnification signals by cross-correlating foreground convergence fields constructed from galaxy shear measurements with background galaxy positional distributions, namely shear-number density correlation. We apply it to the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) survey data. With 27 non-independent data points and their full covariance, $\chi_0^2\approx 34.1$ and $\chi_T^2\approx 24.0$ with respect to the null and the cosmological model with the parameters from HSC shear correlation analyses in Hamana et al. 2020 (arXiv:1906.06041), respectively. The Bayes factor of the two is $\log_{10}B_{T0}\approx 2.2$ assuming equal model probabilities of null and HSC cosmology, showing a clear detection of the magnification signals. Theoretically, the ratio of the shear-number density and shear-shear correlations can provide a constraint on the effective multiplicative shear bias $\bar m$ using internal data themselves. We demonstrate the idea with the signals from our HSC-SSP mock simulations and rescaling the statistical uncertainties to a survey of $15000\deg^2$. For two-bin analyses with background galaxies brighter than $m_{lim}=23$, the combined analyses lead to a forecasted constraint of $\sigma(\bar m) \sim 0.032$, $2.3$ times tighter than that of using the shear-shear correlation alone. Correspondingly, $\sigma(S_8)$ with $S_8=\sigma_8(\Omega_\mathrm{m}/0.3)^{0.5}$ is tightened by $\sim 2.1$ times. Importantly, the joint constraint on $\bar m$ is nearly independent of cosmological parameters. Our studies therefore point to the importance of including the shear-number density correlation in weak lensing analyses, which can provide valuable consistency tests of observational data, and thus to solidify the derived cosmological constraints., Comment: 9 pages, 4 figures; Accepted for publication in PRD

The natural conductivity of as-grown ZnO is $n$-type. It has been challenging to produce stable $p$-type material, which has delayed possible technological applications. In this work, the conductivity transformation from $n$- to $p$-type ZnO films deposited by sputtering was followed as a function of copper and tellurium concentrations and of the substrate temperature during growth (room temperature, $150{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}, 250{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$, and $350{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$). The nominal codopant concentrations ranged from 1 to 12 at %. For the minimum concentration, compensation effects yielded highly resistive ZnO. Nonetheless, by tailoring the concentration of Cu and Te, it was possible to vary the resistivity $({10}^{3}--{10}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}\mathrm{\ensuremath{\Omega}}\phantom{\rule{0.16em}{0ex}}\mathrm{cm})$, mobility $(\ensuremath{\sim}{10}^{\ensuremath{-}2}--{10}^{\ensuremath{\circ}}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}/\mathrm{V}\phantom{\rule{0.16em}{0ex}}\mathrm{s})$, and free-hole density $({10}^{15}--{10}^{20}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3})$ of $p$-type ZnO grown at $250{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. Besides modifying the electrical properties, codoping changed the host band structure significantly, producing a band-gap renormalization from 3.2 eV (UV) to 1.8 eV (red). This control over the band gap is advantageous for applications where controllable photon absorption or emission are sought. Experimentally, films were stable for a period of at least six months. Band-gap engineered $p$-type ZnO:(Cu+Te) films open the possibility for the fabrication of all-ZnO optoelectronic devices such as homojunction solar cells and/or light-emitting diodes.