In this paper we study the consequences of the introduction of a flat boundary on a four-dimensional (4D) covariant rank-2 gauge theory described by a linear combination of linearized gravity and covariant fracton theory. We show that this theory gives rise to a Maxwell-Chern-Simons-like theory of two rank-2 traceless symmetric tensor fields. This induced three-dimensional (3D) theory can be physically traced back to the traceless scalar charge theory of fractons, where the Chern-Simons-like term plays the role of a matter contribution. By further imposing time reversal invariance on the boundary, the Chern-Simons-like term disappears. Importantly, on the boundary of our 4D gauge theory we find a generalized U(1) Kaç-Moody algebra and the induced 3D theory is characterized by the conservation of the dipole moment.

We derive novel recursion relations for all loop amplitude integrands of planar, maximally supersymmetric Yang-Mills theory in terms of unitarity-like “cuts” obtained via sequences of BCFW deformations in momentum-twistor space.

We consider a modified gravity model that we call “dynamical Henneaux-Teitelboim gravity” because of its close relationship with the Henneaux-Teitelboim formulation of unimodular gravity. The latter is a fully diffeomorphism-invariant formulation of unimodular gravity, where full diffeomorphism invariance is achieved by introducing two additional nondynamical fields: a scalar, which plays the role of a cosmological constant, and a three-form whose exterior derivative is the spacetime volume element. Dynamical Henneaux-Teitelboim gravity is a generalization of this model that includes kinetic terms for both the scalar and the three-form with arbitrary couplings. We study the field equations for the cases of spherically symmetric and homogeneous, isotropic configurations. In the spherically symmetric case, we solve the field equations analytically for small values of the coupling to obtain an approximate black hole solution. In the homogeneous and isotropic case, we perturb around de Sitter space to find an approximate cosmological background for our model.

In this paper, we carry out a systematic study of the prospect of testing general relativity with the inspiral signal of black hole binaries that could be detected with TianQin. The study is based on the parametrized post-Einsteinian (ppE) waveform, so that many modified gravity theories can be covered simultaneously. We consider black hole binaries with total masses ranging from $10M_{\odot }\sim {10}^7{M}_{\odot }$ and ppE corrections at post-Newtonian (PN) orders ranging from $-4\mathrm{PN}$ to 2PN. Compared to the current ground-based detectors, TianQin can improve the constraints on the ppE phase parameter $\beta$ by orders of magnitude. For example, the improvement at the $-4\mathrm{PN}$ and 2PN orders can be about 13 and 3 orders of magnitude (compared to the results from GW150914), respectively. Compared to future ground-based detectors, such as ET, TianQin is expected to be superior below the $-1\mathrm{PN}$ order, and for corrections above the $-0.5\mathrm{PN}$ order, TianQin is still competitive near the large-mass end of the low-mass range [$10M_{\odot },{10}^3{M}_{\odot }$]. Compared to the future space-based detector LISA, TianQin can be competitive in the lower-mass end as the PN order is increased. For example, at the $-4\mathrm{PN}$ order, LISA is always superior for sources more massive than about $30M_{\odot }$, while at the 2PN order, TianQin becomes competitive for sources less massive than about ${10}^4{M}_{\odot }$. We also study the scientific potentials of detector networks involving TianQin, LISA, and ET, and discuss the constraints on specific theories such as the dynamic Chern-Simons theory and the Einstein-dilaton Gauss-Bonnet theory.

We investigate the linear stability of scalarized black holes (BHs) and neutron stars (NSs) in the Einstein-scalar-Gauss-Bonnet (GB) theories against the odd- and even-parity perturbations including the higher multipole modes. We show that the angular propagation speeds in the even-parity perturbations in the $\ell \to \infty$ limit, with $\ell$ being the angular multipole moments, become imaginary and hence scalarized BH solutions suffer from the gradient instability. We show that such an instability appears irrespective of the structure of the higher-order terms in the GB coupling function and is caused purely due to the existence of the leading quadratic term and the boundary condition that the value of the scalar field vanishes at the spatial infinity. This indicates that the gradient instability appears at the point in the mass-charge diagram where the scalarized branches bifurcate from the Schwarzschild branch. We also show that scalarized BH solutions realized in a nonlinear scalarization model also suffer from the gradient instability in the even-parity perturbations. Our result also suggests the gradient instability of the exterior solutions of the static and spherically-symmetric scalarized NS solutions induced by the same GB coupling functions.

Simultaneous measurements of neutron star masses and radii can be used to constrain deviations from general relativity (GR) as was recently demonstrated for the spontaneous scalarization model of Damour and Esposito-Farèse (DEF). Here, we investigate the general applicability of the same procedure beyond this single example. We first show that a simple variation of the DEF model renders the same mass-radius measurements ineffective for obtaining constraints. On the other hand, a recently popular and distinct model of scalarization that arises in scalar-Gauss-Bonnet theory can be constrained similarly to the original DEF model, albeit due to a slightly different underlying mechanism. These establish that using the mass-radius data can potentially constrain various theories of gravity, but the method also has limitations.

Gravitational waves (GWs) from merging binary black holes (BHs) enable unprecedented tests of gravitational theories beyond Einstein’s general relativity (GR) in highly nonlinear, dynamical regimes. Such GW measurements require an accurate description of GW signatures that may arise in alternative gravitational models. In this work, we focus on a class of higher-curvature extensions of GR, the scalar-Gauss-Bonnet theories, where BHs can develop scalar hair. In an inspiraling binary system, this leads to scalar-induced tidal effects in the dynamics and radiation. We calculate the dominant adiabatic dipolar tidal effects via an approximation scheme based on expansions in post-Newtonian, higher-curvature, and tidal corrections. The tidal effects depend on a characteristic scalar Love number, which we compute using BH perturbation theory, and have the same scaling with GW frequency as the higher-curvature corrections. We perform case studies to characterize the net size and parameter dependencies of these effects, showing that at low frequencies, tidal effects dominate over the higher-curvature contributions for small couplings within current bounds, regardless of the total BH mass, while at high frequencies they are subdominant. We further consider prospects observing both of these regimes, which would be interesting for breaking parameter degeneracies, with multiband detections of LISA and ground-based detectors or the Einstein Telescope alone. We also assess the frequency range of the transition between these regimes by numerically solving the energy balance law. Our results highlight the importance of the dipolar scalar tidal effects for BHs with scalar hair, which arise in several beyond-GR paradigms, and provide ready-to-use inputs for improved GW constraints on Gauss-Bonnet theories.

We find that QCD can create the cosmological matter abundance via out-of-equilibrium processes during the QCD phase transition, that is what we call the QCD preheating, where the dynamic transition of the QCD vacuum characterized by the quark condensate takes place instantaneously. This mechanism works when the Universe undergoes subsequent supercooled QCD transition. We also find that the QCD preheating can work to create the baryon asymmetry of the Universe if there is the new physics communicated with QCD. These are new pictures of the thermal history around the QCD-phase transition epoch, and thus the dynamic aspect of the QCD vacuum opens a new frontier to explore low-scale matter generation such as baryogenesis. Pursuing the QCD reheating era would also help deeply understanding the subatomic-scale physics in the thermal history of the Universe.

The aim of this paper is to highlight the challenges and potential gains surrounding a coherent description of physics from the high-energy scales of inflation down to the lower energy scales probed in particle-physics experiments. As an example, we revisit the way inflation can be realized within an effective minimal supersymmetric standard model (eMSSM), in which the $LLe$ and $udd$ flat directions are lifted by the combined effect of soft-supersymmetric-breaking masses already present in the MSSM, together with the addition of effective nonrenormalizable operators. We clarify some features of the model and address the question of the one-loop renormalization group improvement of the inflationary potential, discussing its impact on the fine-tuning of the model. We also compare the parameter space that is compatible with current observations (in particular the amplitude, $A_{\mathrm{S}}$, and the spectral index, $n_{\mathrm{S}}$, of the primordial cosmological fluctuations) at tree level and at one loop, and discuss the role of reheating. Finally we perform combined fits of particle and cosmological observables (mainly $A_{\mathrm{S}}$, $n_{\mathrm{S}}$, the Higgs mass, and the cold-dark-matter energy density) with the one-loop inflationary potential applied to some examples of dark-matter annihilation channels (Higgs-funnel, Higgsinos and A-funnel), and discuss the status of the ensuing MSSM spectra with respect to the LHC searches.

Unresolved sources of gravitational waves can create a stochastic gravitational wave background (SGWB) which may have intrinsic or extrinsic anisotropies. The angular power spectrum is a well-suited estimator for characterizing diffuse anisotropic distributions in the sky. Here we estimate the first model-independent all-sky all-frequency SGWB angular power spectra in the 20–1726 Hz frequency range from the third observing run (O3) of the Advanced LIGO and Advanced Virgo detectors. We develop a method to use the spectrum’s signal-to-noise ratio as the detection statistic and show that the shape of the distribution of the statistic obtained from the data agrees with the analytical model with a modified value of the parameter. Since we find the data to be consistent with noise, 95% confidence Bayesian upper limits are set on the angular power spectra, ranging from $C_{\ell }^{1/2}\le (3.0\times {10}^{-9}–0.73){\mathrm{sr}}^{-1}$. We also introduce a method to combine the narrow band angular power spectra to obtain estimators for broadband SGWB. These results can directly constrain theoretical models that predict the SGWB angular power spectra and for estimating or constraining the corresponding parameters. In addition, the results and the techniques introduced in this work can be useful for performing correlation-based searches, for instance, with electromagnetic observations.

We apply statistical inference on the Pierre Auger Open Data to discern the mass composition of cosmic rays at different energies. Working with longitudinal electromagnetic profiles of cosmic ray showers, in particular their peaking depths $X_{\max }$, we employ central moments of the $X_{\max }$ distributions to discriminate between different shower compositions. We find that already the first few moments entail the most relevant information to infer the primary cosmic ray mass spectrum. Our approach, based on an unbinned likelihood, allows us to consistently account for sources of statistical uncertainties due to finite datasets, both measured and simulated, as well as systematic effects. Finally, we provide a quantitative comparison of different high energy hadronic interaction models available in the atmospheric shower simulation codes.

We propose a new framework for quantum field theory (QFT) studies that allows us to represent field excitations as quantum channels. We demonstrate the inner workings of the proposed scheme for three universal states: a regularized vacuum state, a thermal state of a one-dimensional QFT system, and the lattice-regulated thermofield double state of two identical free QFTs. We investigate the actions of unitary and nonunitary bosonic Gaussian channels (including Petz recovery maps). To evaluate and quantify the character of the channel static action and channel-induced dynamics, we calculate quantum entropies and fidelities.

In this work we study the role of the $f_0(980)$ and $a_0(980)$ resonances in the low $K^{+}{K}^{-}$ and $K^0{\overline{K}}^0$ invariant-mass region of the $B^{-}\to {\pi }^{-}{K}^{+}{K}^{-}$ and $B^{-}\to {\pi }^{-}{K}^0{\overline{K}}^0$ reactions. The amplitudes are calculated by using the chiral unitary SU(3) formalism, in which these two resonances are dynamically generated from the unitary pseudoscalar-pseudoscalar coupled-channel approach. The amplitudes are then used as input in the evaluation of the mass distributions with respect to the $K^{+}{K}^{-}$ and $K^0{\overline{K}}^0$ invariant masses, where the contributions coming from the $I=0$ and $I=1$ components are explicitly assessed. Furthermore, the contribution of the $K^{*}(892{)}^0{K}^{-}$ production and its influence on the ${\pi }^{-}{K}^{+}$ and $K^{+}{K}^{-}$ systems are also evaluated, showing that there is no significant strength for small $K^{+}{K}^{-}$ invariant mass. Finally, the final distributions of $M_{\mathrm{inv}}^2(K^{\pm }{K}^{\mp })$ for the $B^{\mp }\to {\pi }^{\mp }{K}^{\pm }{K}^{\mp }$ reactions are estimated and compared with the LHCb data. Our results indicate that the $I=0$ component tied to the $f_0(980)$ excitation generates the dominant contribution in the range of low $K^{+}{K}^{-}$ invariant mass.

We study in detail the dynamics of unstable two-level quantum systems by adopting the Bloch-sphere formalism of qubits. By employing the Bloch-vector representation for such unstable qubit systems, we identify a novel class of critical scenarios in which the so-called energy-level and decay-width vectors, $\mathbf{E}$ and $\mathbf{\Gamma }$, are orthogonal to one another, and the parameter $r=|\mathbf{\Gamma }|/(2|\mathbf{E}|)$ is less than 1. Most remarkably, we find that critical unstable qubit systems exhibit atypical behaviors like coherence-decoherence oscillations when analyzed in an appropriately defined codecaying frame of the system. In the same frame, a unit Bloch vector $\mathbf{b}$ describing a pure critical qubit will sweep out unequal areas during equal intervals of time, while rotating about the vector $\mathbf{E}$. These phenomena emerge beyond the usual oscillatory pattern due to the energy-level difference of the two-level quantum system. Interestingly enough, we observe that these new features will persist even for quasicritical scenarios, in which the vectors $\mathbf{E}$ and $\mathbf{\Gamma }$ are not perfectly orthogonal to each other. Applications of our results to quantum information and to unstable meson-antimeson and other systems are discussed.

We revisit the bottom and $\tau$ Yukawa coupling unification in the supersymmetric 4-2-2 model and present for the first time the sbottom-neutralino coannihilation scenario consistent with the bottom and $\tau$ Yukawa coupling unification. In addition, we present gluino-neutralino, stop-neutralino, stau-neutralino, chargino-neutralino, and A-resonance scenario and show that all such solutions are consistent with existing experimental collider constraints, Planck 2018 dark matter relic density bounds as well as direct and indirect bounds on neutralino-nucleons scattering cross sections. It is shown that in the sbottom-neutralino coannihilation scenario, the sbottom mass is between 1.2 to 3.5 TeV, whereas in the case of gluino-neutralino, stop-neutralino, the gluino mass can be between 1 to 3 TeV and the stop mass in the range of 1 to 3.5 TeV. Moreover, in the case of a coannihilation scenario, the stau and chargino masses can be as heavy as 3.5 TeV, while the A-resonance solutions are in the range of 0.5 to 3.5 TeV. We anticipate that some part of the parameter space will be accessible in the supersymmetry searches at LHC run 3 and beyond.

We analyze scaling functions in the 3D $Z(2)$, $O(2)$, and $O(4)$ universality classes and their finite-size dependence using Monte Carlo simulations of improved ${\varphi }^4$ models. Results for the scaling functions are fitted to the Widom-Griffiths form, using a parametrization also used in analytic calculations. We find good agreement on the level of scaling functions and the location of maxima in the universal part of susceptibilities. We also find that an earlier parametrization of the $O(4)$ scaling function, using 14 parameters, is well reproduced when using the Widom-Griffiths form with only three parameters. We furthermore show that finite-size corrections to the scaling functions are distinctively different in the $Z(2)$ and $O(N)$ universality classes and determine the volume dependence of the peak locations in order parameter and mixed susceptibilities.

We numerically study the phase structure of the two-flavor Schwinger model with matrix product states, focusing on the ($1+1$)-dimensional analog of the $CP$-violating Dashen phase in QCD. We simulate the two-flavor Schwinger model around the point where the positive mass of one fermion flavor corresponds to the negative mass of the other fermion flavor, which is a sign-problem afflicted regime for conventional Monte Carlo techniques. Our results indicate that the model undergoes a $CP$-violating Dashen phase transition at this point, which manifests itself in abrupt changes of the average electric field and the analog of the pion condensate in the model. Studying the scaling of the bipartite entanglement entropy as a function of the volume, we find clear indications that this transition is not of first order.

A search is performed for narrow resonances decaying to final states of two jets, with at least one jet originating from a $b$ quark, in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$. The data set corresponds to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ collected with the CMS detector at the LHC. Jets originating from energetic $b$ hadrons are identified through a $b$-tagging algorithm that utilizes a deep neural network or the presence of a muon inside a jet. The invariant mass spectrum of jet pairs is well described by a smooth parametrization and no evidence for the production of new particles is observed. Upper limits on the production cross section are set for excited $b$ quarks and other resonances decaying to dijet final states containing $b$ quarks. These limits exclude at 95% confidence level models of $Z^{\prime }$ bosons with masses from 1.8 TeV to 2.4 TeV and of excited $b$ quarks with masses from 1.8 TeV to 4.0 TeV. This is the most stringent exclusion of excited $b$ quarks to date.

Measurements of $CP$ asymmetries in charmless three-body decays of $B^{\pm }$ mesons are reported using proton-proton collision data collected by the LHCb detector, corresponding to an integrated luminosity of $5.9{\mathrm{fb}}^{-1}$. The previously observed $CP$ asymmetry in $B^{\pm }\to {\pi }^{\pm }{K}^{+}{K}^{-}$ decays is confirmed, and $CP$ asymmetries are observed with a significance of more than five standard deviations in the $B^{\pm }\to {\pi }^{\pm }{\pi }^{+}{\pi }^{-}$ and $B^{\pm }\to K^{\pm }{K}^{+}{K}^{-}$ decays, while the $CP$ asymmetry of $B^{\pm }\to K^{\pm }{\pi }^{+}{\pi }^{-}$ decays is confirmed to be compatible with zero. The distributions of these asymmetries are also studied as a function of the three-body phase space and suggest contributions from rescattering and resonance interference processes. An indication of the presence of the decays $B^{\pm }\to {\pi }^{\pm }{\chi }_{c0}(1P)$ in both $B^{\pm }\to {\pi }^{\pm }{\pi }^{+}{\pi }^{-}$ and $B^{\pm }\to {\pi }^{\pm }{K}^{+}{K}^{-}$ decays is observed, as is $CP$ violation involving these amplitudes.