Conformal field theories (CFT) play an important role in quantum field theories as they allow for exact studies that are hard to access without the conformal symmetries in place. A remarkable recent development is the application of conformal field theory to periodically driven systems, the so-called Floquet-driven CFTs. A number of recent works have found that there are classes of periodically driven ($1+1$)-dimensional CFTs that can be analytically solved, and that show both heating and nonheating phases, as well as unusual properties in terms of information scrambling. Hitherto, most results have focused on the dynamics of such models at stroboscopic times, i.e., samples taken at each period of the time evolution. In this paper, we consider time evolution at arbitrary real times and derive formulas for the exact time propagation of heating and nonheating classes of Floquet-driven CFTs. This requires a subtle treatment of nonstroboscopic time that leads to different interpretations in terms of curved space-time dynamics in these systems compared to previous results in the literature.

The formalism relating the relativistic three-particle infinite-volume scattering amplitude to the finite-volume spectrum has been developed thus far only for identical or degenerate particles. We provide the generalization to the case of three nondegenerate scalar particles with arbitrary masses. A key quantity in this formalism is the quantization condition, which relates the spectrum to an intermediate K matrix. We derive three versions of this quantization condition, each a natural generalization of the corresponding results for identical particles. In each case we also determine the integral equations relating the intermediate K matrix to the three-particle scattering amplitude, ${\mathcal{M}}_3$. The version that is likely to be most practical involves a single Lorentz-invariant intermediate K matrix, ${\tilde{\mathcal{K}}}_{\mathrm{df},3}$. The other versions involve a matrix of K matrices, with elements distinguished by the choice of which initial and final particles are the spectators. Our approach should allow a straightforward generalization of the relativistic approach to all other three-particle systems of interest.

We present the first determination of the hadronic decays of the lightest exotic $J^{PC}=1^{-+}$ resonance in lattice QCD. Working with SU(3) flavor symmetry, where the up, down and strange-quark masses approximately match the physical strange-quark mass giving $m_{\pi }\sim 700\mathrm{MeV}$, we compute finite-volume spectra on six lattice volumes which constrain a scattering system featuring eight coupled channels. Analytically continuing the scattering amplitudes into the complex-energy plane, we find a pole singularity corresponding to a narrow resonance which shows relatively weak coupling to the open pseudoscalar–pseudoscalar, vector–pseudoscalar and vector–vector decay channels, but large couplings to at least one kinematically closed axial-vector–pseudoscalar channel. Attempting a simple extrapolation of the couplings to physical light-quark mass suggests a broad ${\pi }_1$ resonance decaying dominantly through the $b_1\pi$ mode with much smaller decays into $f_1\pi$, $\rho \pi$, ${\eta }^{\prime }\pi$ and $\eta \pi$. A large total width is potentially in agreement with the experimental ${\pi }_1(1564)$ candidate state observed in $\eta \pi$, ${\eta }^{\prime }\pi$, which we suggest may be heavily suppressed decay channels.

Following an explicit example, we present the chain of steps required for an event-by-event description of hadron production in high energy hadronic and nuclear collisions. We start from incoming nuclei, described in the color glass condensate effective theory, whose collision creates the gluon fields of the glasma. Individual gluons are then sampled from the gluon fields’ Husimi (smeared Wigner) distributions and clustered using a new spacetime based algorithm. Clusters are fed into the Herwig event generator, which performs the hadronization, conserving energy and momentum. We discuss the physical implications of smearing and problems with the quasiparticle picture for the studied processes. We compute spectra of charged hadrons and identified particles and their azimuthal momentum anisotropies, and address systematic uncertainties on observables, resulting from the general lack of detailed knowledge of the hadronization mechanism.

Inspired by the recent report of the exotic states $X_0(2900)$ and $X_1(2900)$ with four different quark flavors in the $D^{-}{K}^{+}$ invariant-mass distributions of the decay process $B^{+}\to D^{+}{D}^{-}{K}^{+}$ by the LHCb Collaboration, we systematically investigate the tetraquarks composed of $ud\overline{s}\overline{c}$ with meson-meson and diquark-antidiquark structures in the quark delocalization color-screening model. We find that the $X_0(2900)$ can be interpreted as the molecular state $\overline{D}{}^{*}{K}^{*}$ with $I{J}^P=00^{+}$. Moreover, two bound states are obtained by the channel coupling calculation, with energies 2341.2 MeV for $I{J}^P=00^{+}$ and 2489.7 MeV for $I{J}^P=01^{+}$, respectively. We also extend our study to the $uc\overline{d}\overline{s}$ systems and find that there is no $S$-wave bound state, so the $D_{s0}(2317)$ cannot be identified as the $DK$ molecular state in the present calculation. Besides, several resonance states with the diquark-antidiquark configuration are possible in both $ud\overline{s}\overline{c}$ and $uc\overline{d}\overline{s}$ systems. The states composed of $ud\overline{s}\overline{b}$ are also possible open bottom tetraquark candidates. All of these open charm and open bottom bound states and resonances are worth investigating in future experiments.

We study chiral algebras associated with Argyres-Douglas theories engineered from M5 branes. For the theory engineered using 6D (2,0) type $J$ theory on a sphere with a single irregular singularity (without mass parameter), its chiral algebra is the minimal model of W algebra of $J$ type. For the theory engineered using an irregular singularity and a regular full singularity, its chiral algebra is the affine Kac-Moody algebra of $J$ type. We can obtain the Schur index of these theories by computing the vacua character of the corresponding chiral algebra.

The general relativistic Poynting-Robertson effect is a dissipative and nonlinear dynamical system obtained by perturbing through radiation processes the geodesic motion of test particles orbiting around a spinning compact object, described by the Kerr metric. Using the Melnikov method, we find that in a suitable range of parameters, chaotic behavior is present in the motion of a test particle driven by the Poynting-Robertson effect in the Kerr equatorial plane.

Dynamical capture is a possible formation channel for binary black hole (BBH) mergers leading to highly eccentric merger dynamics and to gravitational wave (GW) signals that are morphologically different from those of quasicircular mergers. The future detection of these mergers by ground- or space-based GW interferometers can provide invaluable insights on astrophysical black holes, but it requires precise predictions and dedicated waveform models for the analysis. We present a state of the art effective-one-body (EOB) model for the multipolar merger-ringdown waveform from dynamical capture black hole mergers with arbitrary mass-ratio and nonprecessing spins. The model relies on analytical descriptions of the radiation reaction and waveform along generic orbits that are obtained by incorporating generic Newtonian prefactors in the expressions used in the quasicircular case. We demonstrate that the model reliably accounts for the rich phenomenology of dynamical captures, from direct plunge to successive close encounters up to merger. The parameter space is fully characterized in terms of the initial energy and angular momentum. Our model reproduces to a few percent the scattering angle from ten equal-mass, nonspinning, hyperbolic encounter numerical-relativity (NR) simulations. The agreement can be further improved by incorporating sixth post-Newtonian results in one of the EOB potentials while tuning currently unknown analytical parameters. Our results suggest that NR simulations of hyperbolic encounters (and dynamical captures) can be used to inform EOB waveform models for generic BBH mergers and encounters for present and future GW detectors.

The higher multipoles of gravitational wave signals from coalescing compact binaries play a vital role in the accurate reconstruction of source properties, bringing about a deeper and nuanced understanding of fundamental physics and astrophysics. Their effect is most pronounced in systems with asymmetric masses having an orbital geometry that is not face-on. The detection of higher multipoles of gravitational wave signals from any single, isolated merger event is challenging, as there is much less power in comparison to the dominant quadrupole mode. In this paper, we present a new method for their detection by combining multiple events observed in interferometric gravitational wave detectors. Sub-dominant modes present in (the inspiral part of) the signal from separate events are stacked using time-frequency spectrogram of the data. We demonstrate that this procedure enhances the signal-to-noise ratio of the higher-multipole components and thereby leads to increased chances of their detection. From Monte Carlo simulations we estimate that a combination of $\sim 100$ events observed in two-detector coincidence can lead to the detection of the higher-multipole components with a $\ge 95\%$ detection probability. The Advanced LIGO detectors are expected to record these many binary black hole merger events within a month of operation at design sensitivity. We also present results from the analysis of data from first and second observing runs containing previously detected events using our new method.

We study the influence of lepton flavor asymmetries on the formation and the mass spectrum of primordial black holes. We estimate the detectability of their mergers with LIGO/Virgo and show that the currently published gravitational wave events may actually be described by a primordial black hole spectrum from nonzero asymmetries. We suggest to use gravitational-wave astronomy as a novel tool to probe how lepton flavor asymmetric the Universe has been before the onset of neutrino oscillations.

We model the quiescent luminosity of accreting neutron stars with several equation of states (EOSs), including the effect of pion condensation and superfluidity. As a consequence of comparison with the observations, we show that the results with Togashi EOS (the strong direct Urca process is forbidden) and TM1e EOS (mass at direct Urca process is $2.06M_{\odot }$) can explain the observations well by considering pion condensation and the effect of superfluidity, while LS220 EOS and TM1 EOS can explain the observations well by considering the baryon direct Urca process and the effect of superfluidity. Besides, we compare the results with the observations of a neutron star RX J0812.4-3114 which has the low average mass accretion rate ($⟨\dot{M}⟩\sim (4–15)\times {10}^{-12}{M}_{\odot }{\mathrm{yr}}^{-1}$) but high thermal luminosity ($L_q^{\infty }\sim (0.6–3)\times {10}^{33}\mathrm{erg}{\mathrm{s}}^{-1}$), and we suggest that a low-mass neutron star ($<1M_{\odot }$) with minimum cooling can explain the lower limit of the observation of thermal luminosity of RX J0812.4-3114, which is qualitatively consistent with the previous work [Zhao et al., Soft excess in the quiescent Be/X-ray pulsar RX J0812.4-3114, Mon. Not. R. Astron. Soc. 488, 4427 (2019)]. However, to explain its upper limit, some other heating mechanisms besides standard deep crustal heating may be needed.

In the present work, $k_T$-factorization formalism is applied to compute the exclusive dilepton production by timelike Compton scattering (TCS) in $eA$, $pA$, and $AA$ collisions. The nuclear effects are investigated considering heavy and light ions. The production cross section in terms of the invariant mass and rapidity distribution of the lepton pair is shown. The analysis is done for electron-ion collisions at the Large Hadron-Electron Collider (LHeC), its high-energy upgrade (HE-LHeC), and at the Future Circular Collider (FCC) in lepton-hadron mode. Additionally, ultraperipheral heavy ion collisions at future runs of the Large Hadron Collider (LHC) and at the FCC (hadron-hadron mode) are also considered.

In this work, we investigate the reaction of $\gamma \gamma \to D\overline{D}$, taking into account the $S$-wave $D\overline{D}$ final state interaction. By fitting to the $D\overline{D}$ invariant mass distributions measured by the Belle and BABAR Collaborations, we obtain a good reproduction of the data by means of a $D\overline{D}$ amplitude that produces a bound $D\overline{D}$ state with isospin $I=0$ close to threshold. The error bands of the fits indicate, however, that more precise data on this reaction are needed to be more assertive about the position and width of such a state.

We present a systematic method to expand the quantum complexity of interacting theory in a series of coupling constants. The complexity is evaluated by the operator approach in which the transformation matrix between the second quantization operators of the reference state and the target state defines the quantum gate. We start with two coupled oscillators and perturbatively evaluate the geodesic length of the associated group manifold of the gate matrix. Next, we generalize the analysis to $N$ coupled oscillators, which describes the lattice $\lambda {\varphi }^4$ theory. Especially, we introduce simple diagrams to represent the perturbative series and construct simple rules to efficiently calculate the complexity. General formulas are obtained for the higher-order complexity of excited states. We present several diagrams to illuminate the properties of complexity and show that the interaction correction to complexity may be positive or negative depending on the magnitude of the reference-state frequency.

We discuss dynamics of massive Klein-Gordon fields in two-dimensional anti-de Sitter spacetimes (${\mathrm{AdS}}_2$), in particular conserved quantities and nonmodal instability on the future Poincaré horizon called, respectively, the Aretakis constants and the Aretakis instability. We find out the geometrical meaning of the Aretakis constants and instability in a parallel-transported frame along a null geodesic; i.e., some components of the higher-order covariant derivatives of the field in the parallel-transported frame are constant or unbounded at the late time. Because ${\mathrm{AdS}}_2$ is maximally symmetric, any null hypersurfaces have the same geometrical properties. Thus, if we prepare parallel-transported frames along any null hypersurfaces, we can show that the same instability emerges not only on the future Poincaré horizon but also on any null hypersurfaces. This implies that the Aretakis instability in ${\mathrm{AdS}}_2$ is the result of singular behaviors of the higher-order covariant derivatives of the fields on the whole AdS infinity, rather than a blowup on a specific null hypersurface. It is also discussed that the Aretakis constants and instability are related to the conformal Killing tensors. We further explicitly demonstrate that the Aretakis constants can be derived from ladder operators constructed from the spacetime conformal symmetry.

We study the post-Minkowskian (PM) and post-Newtonian (PN) expansions of the gravitational three-body effective potential. At order 2PM a formal result is given in terms of a differential operator acting on the maximal generalized cut of the one-loop triangle integral. We compute the integral in all kinematic regions and show that the leading terms in the PN expansion are reproduced. We then perform the PN expansion unambiguously at the level of the integrand. Finding agreement with the 2PN three-body potential after integration, we explicitly present new $G^2{v}^4$-contributions at order 3PN and outline the generalization to $G^2{v}^{2n}$. The integrals that represent the essential input for these results are obtained by applying the recent Yangian bootstrap directly to their $\epsilon$-expansion around three dimensions. The coordinate space Yangian generator that we employ to obtain these integrals can be understood as a special conformal symmetry in a dual momentum space.

We perform an off-shell treatment of asymptotically decelerating spatially flat Friedmann-Robertson-Walker (FRW) spacetimes at future null infinity. We obtain supertranslation and superrotationlike asymptotic diffeomorphisms which are consistent with the global symmetries of FRW, and we compute how the asymptotic data are transformed under them. Further, we study in detail the effect of these diffeomorphisms on some simple backgrounds including unperturbed FRW and Sultana-Dyer black hole. In particular, we investigate how these transformations act on several cosmologically perturbed backgrounds.